/* * Copyright © 2009 Keith Packard * * Permission to use, copy, modify, distribute, and sell this software and its * documentation for any purpose is hereby granted without fee, provided that * the above copyright notice appear in all copies and that both that copyright * notice and this permission notice appear in supporting documentation, and * that the name of the copyright holders not be used in advertising or * publicity pertaining to distribution of the software without specific, * written prior permission. The copyright holders make no representations * about the suitability of this software for any purpose. It is provided "as * is" without express or implied warranty. * * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE * OF THIS SOFTWARE. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include "drm_crtc_helper_internal.h" struct dp_aux_backlight { struct backlight_device *base; struct drm_dp_aux *aux; struct drm_edp_backlight_info info; bool enabled; }; /** * DOC: dp helpers * * These functions contain some common logic and helpers at various abstraction * levels to deal with Display Port sink devices and related things like DP aux * channel transfers, EDID reading over DP aux channels, decoding certain DPCD * blocks, ... */ /* Helpers for DP link training */ static u8 dp_link_status(const u8 link_status[DP_LINK_STATUS_SIZE], int r) { return link_status[r - DP_LANE0_1_STATUS]; } static u8 dp_get_lane_status(const u8 link_status[DP_LINK_STATUS_SIZE], int lane) { int i = DP_LANE0_1_STATUS + (lane >> 1); int s = (lane & 1) * 4; u8 l = dp_link_status(link_status, i); return (l >> s) & 0xf; } bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE], int lane_count) { u8 lane_align; u8 lane_status; int lane; lane_align = dp_link_status(link_status, DP_LANE_ALIGN_STATUS_UPDATED); if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0) return false; for (lane = 0; lane < lane_count; lane++) { lane_status = dp_get_lane_status(link_status, lane); if ((lane_status & DP_CHANNEL_EQ_BITS) != DP_CHANNEL_EQ_BITS) return false; } return true; } EXPORT_SYMBOL(drm_dp_channel_eq_ok); bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE], int lane_count) { int lane; u8 lane_status; for (lane = 0; lane < lane_count; lane++) { lane_status = dp_get_lane_status(link_status, lane); if ((lane_status & DP_LANE_CR_DONE) == 0) return false; } return true; } EXPORT_SYMBOL(drm_dp_clock_recovery_ok); u8 drm_dp_get_adjust_request_voltage(const u8 link_status[DP_LINK_STATUS_SIZE], int lane) { int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); int s = ((lane & 1) ? DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT : DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT); u8 l = dp_link_status(link_status, i); return ((l >> s) & 0x3) << DP_TRAIN_VOLTAGE_SWING_SHIFT; } EXPORT_SYMBOL(drm_dp_get_adjust_request_voltage); u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SIZE], int lane) { int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); int s = ((lane & 1) ? DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT : DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT); u8 l = dp_link_status(link_status, i); return ((l >> s) & 0x3) << DP_TRAIN_PRE_EMPHASIS_SHIFT; } EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis); /* DP 2.0 128b/132b */ u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], int lane) { int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); int s = ((lane & 1) ? DP_ADJUST_TX_FFE_PRESET_LANE1_SHIFT : DP_ADJUST_TX_FFE_PRESET_LANE0_SHIFT); u8 l = dp_link_status(link_status, i); return (l >> s) & 0xf; } EXPORT_SYMBOL(drm_dp_get_adjust_tx_ffe_preset); u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], unsigned int lane) { unsigned int offset = DP_ADJUST_REQUEST_POST_CURSOR2; u8 value = dp_link_status(link_status, offset); return (value >> (lane << 1)) & 0x3; } EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor); void drm_dp_link_train_clock_recovery_delay(const struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { unsigned long rd_interval = dpcd[DP_TRAINING_AUX_RD_INTERVAL] & DP_TRAINING_AUX_RD_MASK; if (rd_interval > 4) drm_dbg_kms(aux->drm_dev, "%s: AUX interval %lu, out of range (max 4)\n", aux->name, rd_interval); if (rd_interval == 0 || dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14) rd_interval = 100; else rd_interval *= 4 * USEC_PER_MSEC; usleep_range(rd_interval, rd_interval * 2); } EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay); static void __drm_dp_link_train_channel_eq_delay(const struct drm_dp_aux *aux, unsigned long rd_interval) { if (rd_interval > 4) drm_dbg_kms(aux->drm_dev, "%s: AUX interval %lu, out of range (max 4)\n", aux->name, rd_interval); if (rd_interval == 0) rd_interval = 400; else rd_interval *= 4 * USEC_PER_MSEC; usleep_range(rd_interval, rd_interval * 2); } void drm_dp_link_train_channel_eq_delay(const struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { __drm_dp_link_train_channel_eq_delay(aux, dpcd[DP_TRAINING_AUX_RD_INTERVAL] & DP_TRAINING_AUX_RD_MASK); } EXPORT_SYMBOL(drm_dp_link_train_channel_eq_delay); void drm_dp_lttpr_link_train_clock_recovery_delay(void) { usleep_range(100, 200); } EXPORT_SYMBOL(drm_dp_lttpr_link_train_clock_recovery_delay); static u8 dp_lttpr_phy_cap(const u8 phy_cap[DP_LTTPR_PHY_CAP_SIZE], int r) { return phy_cap[r - DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER1]; } void drm_dp_lttpr_link_train_channel_eq_delay(const struct drm_dp_aux *aux, const u8 phy_cap[DP_LTTPR_PHY_CAP_SIZE]) { u8 interval = dp_lttpr_phy_cap(phy_cap, DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER1) & DP_TRAINING_AUX_RD_MASK; __drm_dp_link_train_channel_eq_delay(aux, interval); } EXPORT_SYMBOL(drm_dp_lttpr_link_train_channel_eq_delay); u8 drm_dp_link_rate_to_bw_code(int link_rate) { switch (link_rate) { case 1000000: return DP_LINK_BW_10; case 1350000: return DP_LINK_BW_13_5; case 2000000: return DP_LINK_BW_20; default: /* Spec says link_bw = link_rate / 0.27Gbps */ return link_rate / 27000; } } EXPORT_SYMBOL(drm_dp_link_rate_to_bw_code); int drm_dp_bw_code_to_link_rate(u8 link_bw) { switch (link_bw) { case DP_LINK_BW_10: return 1000000; case DP_LINK_BW_13_5: return 1350000; case DP_LINK_BW_20: return 2000000; default: /* Spec says link_rate = link_bw * 0.27Gbps */ return link_bw * 27000; } } EXPORT_SYMBOL(drm_dp_bw_code_to_link_rate); #define AUX_RETRY_INTERVAL 500 /* us */ static inline void drm_dp_dump_access(const struct drm_dp_aux *aux, u8 request, uint offset, void *buffer, int ret) { const char *arrow = request == DP_AUX_NATIVE_READ ? "->" : "<-"; if (ret > 0) drm_dbg_dp(aux->drm_dev, "%s: 0x%05x AUX %s (ret=%3d) %*ph\n", aux->name, offset, arrow, ret, min(ret, 20), buffer); else drm_dbg_dp(aux->drm_dev, "%s: 0x%05x AUX %s (ret=%3d)\n", aux->name, offset, arrow, ret); } /** * DOC: dp helpers * * The DisplayPort AUX channel is an abstraction to allow generic, driver- * independent access to AUX functionality. Drivers can take advantage of * this by filling in the fields of the drm_dp_aux structure. * * Transactions are described using a hardware-independent drm_dp_aux_msg * structure, which is passed into a driver's .transfer() implementation. * Both native and I2C-over-AUX transactions are supported. */ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request, unsigned int offset, void *buffer, size_t size) { struct drm_dp_aux_msg msg; unsigned int retry, native_reply; int err = 0, ret = 0; memset(&msg, 0, sizeof(msg)); msg.address = offset; msg.request = request; msg.buffer = buffer; msg.size = size; mutex_lock(&aux->hw_mutex); /* * The specification doesn't give any recommendation on how often to * retry native transactions. We used to retry 7 times like for * aux i2c transactions but real world devices this wasn't * sufficient, bump to 32 which makes Dell 4k monitors happier. */ for (retry = 0; retry < 32; retry++) { if (ret != 0 && ret != -ETIMEDOUT) { usleep_range(AUX_RETRY_INTERVAL, AUX_RETRY_INTERVAL + 100); } ret = aux->transfer(aux, &msg); if (ret >= 0) { native_reply = msg.reply & DP_AUX_NATIVE_REPLY_MASK; if (native_reply == DP_AUX_NATIVE_REPLY_ACK) { if (ret == size) goto unlock; ret = -EPROTO; } else ret = -EIO; } /* * We want the error we return to be the error we received on * the first transaction, since we may get a different error the * next time we retry */ if (!err) err = ret; } drm_dbg_kms(aux->drm_dev, "%s: Too many retries, giving up. First error: %d\n", aux->name, err); ret = err; unlock: mutex_unlock(&aux->hw_mutex); return ret; } /** * drm_dp_dpcd_read() - read a series of bytes from the DPCD * @aux: DisplayPort AUX channel (SST or MST) * @offset: address of the (first) register to read * @buffer: buffer to store the register values * @size: number of bytes in @buffer * * Returns the number of bytes transferred on success, or a negative error * code on failure. -EIO is returned if the request was NAKed by the sink or * if the retry count was exceeded. If not all bytes were transferred, this * function returns -EPROTO. Errors from the underlying AUX channel transfer * function, with the exception of -EBUSY (which causes the transaction to * be retried), are propagated to the caller. */ ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset, void *buffer, size_t size) { int ret; /* * HP ZR24w corrupts the first DPCD access after entering power save * mode. Eg. on a read, the entire buffer will be filled with the same * byte. Do a throw away read to avoid corrupting anything we care * about. Afterwards things will work correctly until the monitor * gets woken up and subsequently re-enters power save mode. * * The user pressing any button on the monitor is enough to wake it * up, so there is no particularly good place to do the workaround. * We just have to do it before any DPCD access and hope that the * monitor doesn't power down exactly after the throw away read. */ if (!aux->is_remote) { ret = drm_dp_dpcd_access(aux, DP_AUX_NATIVE_READ, DP_DPCD_REV, buffer, 1); if (ret != 1) goto out; } if (aux->is_remote) ret = drm_dp_mst_dpcd_read(aux, offset, buffer, size); else ret = drm_dp_dpcd_access(aux, DP_AUX_NATIVE_READ, offset, buffer, size); out: drm_dp_dump_access(aux, DP_AUX_NATIVE_READ, offset, buffer, ret); return ret; } EXPORT_SYMBOL(drm_dp_dpcd_read); /** * drm_dp_dpcd_write() - write a series of bytes to the DPCD * @aux: DisplayPort AUX channel (SST or MST) * @offset: address of the (first) register to write * @buffer: buffer containing the values to write * @size: number of bytes in @buffer * * Returns the number of bytes transferred on success, or a negative error * code on failure. -EIO is returned if the request was NAKed by the sink or * if the retry count was exceeded. If not all bytes were transferred, this * function returns -EPROTO. Errors from the underlying AUX channel transfer * function, with the exception of -EBUSY (which causes the transaction to * be retried), are propagated to the caller. */ ssize_t drm_dp_dpcd_write(struct drm_dp_aux *aux, unsigned int offset, void *buffer, size_t size) { int ret; if (aux->is_remote) ret = drm_dp_mst_dpcd_write(aux, offset, buffer, size); else ret = drm_dp_dpcd_access(aux, DP_AUX_NATIVE_WRITE, offset, buffer, size); drm_dp_dump_access(aux, DP_AUX_NATIVE_WRITE, offset, buffer, ret); return ret; } EXPORT_SYMBOL(drm_dp_dpcd_write); /** * drm_dp_dpcd_read_link_status() - read DPCD link status (bytes 0x202-0x207) * @aux: DisplayPort AUX channel * @status: buffer to store the link status in (must be at least 6 bytes) * * Returns the number of bytes transferred on success or a negative error * code on failure. */ int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux, u8 status[DP_LINK_STATUS_SIZE]) { return drm_dp_dpcd_read(aux, DP_LANE0_1_STATUS, status, DP_LINK_STATUS_SIZE); } EXPORT_SYMBOL(drm_dp_dpcd_read_link_status); /** * drm_dp_dpcd_read_phy_link_status - get the link status information for a DP PHY * @aux: DisplayPort AUX channel * @dp_phy: the DP PHY to get the link status for * @link_status: buffer to return the status in * * Fetch the AUX DPCD registers for the DPRX or an LTTPR PHY link status. The * layout of the returned @link_status matches the DPCD register layout of the * DPRX PHY link status. * * Returns 0 if the information was read successfully or a negative error code * on failure. */ int drm_dp_dpcd_read_phy_link_status(struct drm_dp_aux *aux, enum drm_dp_phy dp_phy, u8 link_status[DP_LINK_STATUS_SIZE]) { int ret; if (dp_phy == DP_PHY_DPRX) { ret = drm_dp_dpcd_read(aux, DP_LANE0_1_STATUS, link_status, DP_LINK_STATUS_SIZE); if (ret < 0) return ret; WARN_ON(ret != DP_LINK_STATUS_SIZE); return 0; } ret = drm_dp_dpcd_read(aux, DP_LANE0_1_STATUS_PHY_REPEATER(dp_phy), link_status, DP_LINK_STATUS_SIZE - 1); if (ret < 0) return ret; WARN_ON(ret != DP_LINK_STATUS_SIZE - 1); /* Convert the LTTPR to the sink PHY link status layout */ memmove(&link_status[DP_SINK_STATUS - DP_LANE0_1_STATUS + 1], &link_status[DP_SINK_STATUS - DP_LANE0_1_STATUS], DP_LINK_STATUS_SIZE - (DP_SINK_STATUS - DP_LANE0_1_STATUS) - 1); link_status[DP_SINK_STATUS - DP_LANE0_1_STATUS] = 0; return 0; } EXPORT_SYMBOL(drm_dp_dpcd_read_phy_link_status); static bool is_edid_digital_input_dp(const struct edid *edid) { return edid && edid->revision >= 4 && edid->input & DRM_EDID_INPUT_DIGITAL && (edid->input & DRM_EDID_DIGITAL_TYPE_MASK) == DRM_EDID_DIGITAL_TYPE_DP; } /** * drm_dp_downstream_is_type() - is the downstream facing port of certain type? * @dpcd: DisplayPort configuration data * @port_cap: port capabilities * @type: port type to be checked. Can be: * %DP_DS_PORT_TYPE_DP, %DP_DS_PORT_TYPE_VGA, %DP_DS_PORT_TYPE_DVI, * %DP_DS_PORT_TYPE_HDMI, %DP_DS_PORT_TYPE_NON_EDID, * %DP_DS_PORT_TYPE_DP_DUALMODE or %DP_DS_PORT_TYPE_WIRELESS. * * Caveat: Only works with DPCD 1.1+ port caps. * * Returns: whether the downstream facing port matches the type. */ bool drm_dp_downstream_is_type(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4], u8 type) { return drm_dp_is_branch(dpcd) && dpcd[DP_DPCD_REV] >= 0x11 && (port_cap[0] & DP_DS_PORT_TYPE_MASK) == type; } EXPORT_SYMBOL(drm_dp_downstream_is_type); /** * drm_dp_downstream_is_tmds() - is the downstream facing port TMDS? * @dpcd: DisplayPort configuration data * @port_cap: port capabilities * @edid: EDID * * Returns: whether the downstream facing port is TMDS (HDMI/DVI). */ bool drm_dp_downstream_is_tmds(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4], const struct edid *edid) { if (dpcd[DP_DPCD_REV] < 0x11) { switch (dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK) { case DP_DWN_STRM_PORT_TYPE_TMDS: return true; default: return false; } } switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) { case DP_DS_PORT_TYPE_DP_DUALMODE: if (is_edid_digital_input_dp(edid)) return false; fallthrough; case DP_DS_PORT_TYPE_DVI: case DP_DS_PORT_TYPE_HDMI: return true; default: return false; } } EXPORT_SYMBOL(drm_dp_downstream_is_tmds); /** * drm_dp_send_real_edid_checksum() - send back real edid checksum value * @aux: DisplayPort AUX channel * @real_edid_checksum: real edid checksum for the last block * * Returns: * True on success */ bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux, u8 real_edid_checksum) { u8 link_edid_read = 0, auto_test_req = 0, test_resp = 0; if (drm_dp_dpcd_read(aux, DP_DEVICE_SERVICE_IRQ_VECTOR, &auto_test_req, 1) < 1) { drm_err(aux->drm_dev, "%s: DPCD failed read at register 0x%x\n", aux->name, DP_DEVICE_SERVICE_IRQ_VECTOR); return false; } auto_test_req &= DP_AUTOMATED_TEST_REQUEST; if (drm_dp_dpcd_read(aux, DP_TEST_REQUEST, &link_edid_read, 1) < 1) { drm_err(aux->drm_dev, "%s: DPCD failed read at register 0x%x\n", aux->name, DP_TEST_REQUEST); return false; } link_edid_read &= DP_TEST_LINK_EDID_READ; if (!auto_test_req || !link_edid_read) { drm_dbg_kms(aux->drm_dev, "%s: Source DUT does not support TEST_EDID_READ\n", aux->name); return false; } if (drm_dp_dpcd_write(aux, DP_DEVICE_SERVICE_IRQ_VECTOR, &auto_test_req, 1) < 1) { drm_err(aux->drm_dev, "%s: DPCD failed write at register 0x%x\n", aux->name, DP_DEVICE_SERVICE_IRQ_VECTOR); return false; } /* send back checksum for the last edid extension block data */ if (drm_dp_dpcd_write(aux, DP_TEST_EDID_CHECKSUM, &real_edid_checksum, 1) < 1) { drm_err(aux->drm_dev, "%s: DPCD failed write at register 0x%x\n", aux->name, DP_TEST_EDID_CHECKSUM); return false; } test_resp |= DP_TEST_EDID_CHECKSUM_WRITE; if (drm_dp_dpcd_write(aux, DP_TEST_RESPONSE, &test_resp, 1) < 1) { drm_err(aux->drm_dev, "%s: DPCD failed write at register 0x%x\n", aux->name, DP_TEST_RESPONSE); return false; } return true; } EXPORT_SYMBOL(drm_dp_send_real_edid_checksum); static u8 drm_dp_downstream_port_count(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { u8 port_count = dpcd[DP_DOWN_STREAM_PORT_COUNT] & DP_PORT_COUNT_MASK; if (dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE && port_count > 4) port_count = 4; return port_count; } static int drm_dp_read_extended_dpcd_caps(struct drm_dp_aux *aux, u8 dpcd[DP_RECEIVER_CAP_SIZE]) { u8 dpcd_ext[DP_RECEIVER_CAP_SIZE]; int ret; /* * Prior to DP1.3 the bit represented by * DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT was reserved. * If it is set DP_DPCD_REV at 0000h could be at a value less than * the true capability of the panel. The only way to check is to * then compare 0000h and 2200h. */ if (!(dpcd[DP_TRAINING_AUX_RD_INTERVAL] & DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT)) return 0; ret = drm_dp_dpcd_read(aux, DP_DP13_DPCD_REV, &dpcd_ext, sizeof(dpcd_ext)); if (ret < 0) return ret; if (ret != sizeof(dpcd_ext)) return -EIO; if (dpcd[DP_DPCD_REV] > dpcd_ext[DP_DPCD_REV]) { drm_dbg_kms(aux->drm_dev, "%s: Extended DPCD rev less than base DPCD rev (%d > %d)\n", aux->name, dpcd[DP_DPCD_REV], dpcd_ext[DP_DPCD_REV]); return 0; } if (!memcmp(dpcd, dpcd_ext, sizeof(dpcd_ext))) return 0; drm_dbg_kms(aux->drm_dev, "%s: Base DPCD: %*ph\n", aux->name, DP_RECEIVER_CAP_SIZE, dpcd); memcpy(dpcd, dpcd_ext, sizeof(dpcd_ext)); return 0; } /** * drm_dp_read_dpcd_caps() - read DPCD caps and extended DPCD caps if * available * @aux: DisplayPort AUX channel * @dpcd: Buffer to store the resulting DPCD in * * Attempts to read the base DPCD caps for @aux. Additionally, this function * checks for and reads the extended DPRX caps (%DP_DP13_DPCD_REV) if * present. * * Returns: %0 if the DPCD was read successfully, negative error code * otherwise. */ int drm_dp_read_dpcd_caps(struct drm_dp_aux *aux, u8 dpcd[DP_RECEIVER_CAP_SIZE]) { int ret; ret = drm_dp_dpcd_read(aux, DP_DPCD_REV, dpcd, DP_RECEIVER_CAP_SIZE); if (ret < 0) return ret; if (ret != DP_RECEIVER_CAP_SIZE || dpcd[DP_DPCD_REV] == 0) return -EIO; ret = drm_dp_read_extended_dpcd_caps(aux, dpcd); if (ret < 0) return ret; drm_dbg_kms(aux->drm_dev, "%s: DPCD: %*ph\n", aux->name, DP_RECEIVER_CAP_SIZE, dpcd); return ret; } EXPORT_SYMBOL(drm_dp_read_dpcd_caps); /** * drm_dp_read_downstream_info() - read DPCD downstream port info if available * @aux: DisplayPort AUX channel * @dpcd: A cached copy of the port's DPCD * @downstream_ports: buffer to store the downstream port info in * * See also: * drm_dp_downstream_max_clock() * drm_dp_downstream_max_bpc() * * Returns: 0 if either the downstream port info was read successfully or * there was no downstream info to read, or a negative error code otherwise. */ int drm_dp_read_downstream_info(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE], u8 downstream_ports[DP_MAX_DOWNSTREAM_PORTS]) { int ret; u8 len; memset(downstream_ports, 0, DP_MAX_DOWNSTREAM_PORTS); /* No downstream info to read */ if (!drm_dp_is_branch(dpcd) || dpcd[DP_DPCD_REV] == DP_DPCD_REV_10) return 0; /* Some branches advertise having 0 downstream ports, despite also advertising they have a * downstream port present. The DP spec isn't clear on if this is allowed or not, but since * some branches do it we need to handle it regardless. */ len = drm_dp_downstream_port_count(dpcd); if (!len) return 0; if (dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE) len *= 4; ret = drm_dp_dpcd_read(aux, DP_DOWNSTREAM_PORT_0, downstream_ports, len); if (ret < 0) return ret; if (ret != len) return -EIO; drm_dbg_kms(aux->drm_dev, "%s: DPCD DFP: %*ph\n", aux->name, len, downstream_ports); return 0; } EXPORT_SYMBOL(drm_dp_read_downstream_info); /** * drm_dp_downstream_max_dotclock() - extract downstream facing port max dot clock * @dpcd: DisplayPort configuration data * @port_cap: port capabilities * * Returns: Downstream facing port max dot clock in kHz on success, * or 0 if max clock not defined */ int drm_dp_downstream_max_dotclock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4]) { if (!drm_dp_is_branch(dpcd)) return 0; if (dpcd[DP_DPCD_REV] < 0x11) return 0; switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) { case DP_DS_PORT_TYPE_VGA: if ((dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE) == 0) return 0; return port_cap[1] * 8000; default: return 0; } } EXPORT_SYMBOL(drm_dp_downstream_max_dotclock); /** * drm_dp_downstream_max_tmds_clock() - extract downstream facing port max TMDS clock * @dpcd: DisplayPort configuration data * @port_cap: port capabilities * @edid: EDID * * Returns: HDMI/DVI downstream facing port max TMDS clock in kHz on success, * or 0 if max TMDS clock not defined */ int drm_dp_downstream_max_tmds_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4], const struct edid *edid) { if (!drm_dp_is_branch(dpcd)) return 0; if (dpcd[DP_DPCD_REV] < 0x11) { switch (dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK) { case DP_DWN_STRM_PORT_TYPE_TMDS: return 165000; default: return 0; } } switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) { case DP_DS_PORT_TYPE_DP_DUALMODE: if (is_edid_digital_input_dp(edid)) return 0; /* * It's left up to the driver to check the * DP dual mode adapter's max TMDS clock. * * Unfortunately it looks like branch devices * may not fordward that the DP dual mode i2c * access so we just usually get i2c nak :( */ fallthrough; case DP_DS_PORT_TYPE_HDMI: /* * We should perhaps assume 165 MHz when detailed cap * info is not available. But looks like many typical * branch devices fall into that category and so we'd * probably end up with users complaining that they can't * get high resolution modes with their favorite dongle. * * So let's limit to 300 MHz instead since DPCD 1.4 * HDMI 2.0 DFPs are required to have the detailed cap * info. So it's more likely we're dealing with a HDMI 1.4 * compatible* device here. */ if ((dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE) == 0) return 300000; return port_cap[1] * 2500; case DP_DS_PORT_TYPE_DVI: if ((dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE) == 0) return 165000; /* FIXME what to do about DVI dual link? */ return port_cap[1] * 2500; default: return 0; } } EXPORT_SYMBOL(drm_dp_downstream_max_tmds_clock); /** * drm_dp_downstream_min_tmds_clock() - extract downstream facing port min TMDS clock * @dpcd: DisplayPort configuration data * @port_cap: port capabilities * @edid: EDID * * Returns: HDMI/DVI downstream facing port min TMDS clock in kHz on success, * or 0 if max TMDS clock not defined */ int drm_dp_downstream_min_tmds_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4], const struct edid *edid) { if (!drm_dp_is_branch(dpcd)) return 0; if (dpcd[DP_DPCD_REV] < 0x11) { switch (dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK) { case DP_DWN_STRM_PORT_TYPE_TMDS: return 25000; default: return 0; } } switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) { case DP_DS_PORT_TYPE_DP_DUALMODE: if (is_edid_digital_input_dp(edid)) return 0; fallthrough; case DP_DS_PORT_TYPE_DVI: case DP_DS_PORT_TYPE_HDMI: /* * Unclear whether the protocol converter could * utilize pixel replication. Assume it won't. */ return 25000; default: return 0; } } EXPORT_SYMBOL(drm_dp_downstream_min_tmds_clock); /** * drm_dp_downstream_max_bpc() - extract downstream facing port max * bits per component * @dpcd: DisplayPort configuration data * @port_cap: downstream facing port capabilities * @edid: EDID * * Returns: Max bpc on success or 0 if max bpc not defined */ int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4], const struct edid *edid) { if (!drm_dp_is_branch(dpcd)) return 0; if (dpcd[DP_DPCD_REV] < 0x11) { switch (dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK) { case DP_DWN_STRM_PORT_TYPE_DP: return 0; default: return 8; } } switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) { case DP_DS_PORT_TYPE_DP: return 0; case DP_DS_PORT_TYPE_DP_DUALMODE: if (is_edid_digital_input_dp(edid)) return 0; fallthrough; case DP_DS_PORT_TYPE_HDMI: case DP_DS_PORT_TYPE_DVI: case DP_DS_PORT_TYPE_VGA: if ((dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE) == 0) return 8; switch (port_cap[2] & DP_DS_MAX_BPC_MASK) { case DP_DS_8BPC: return 8; case DP_DS_10BPC: return 10; case DP_DS_12BPC: return 12; case DP_DS_16BPC: return 16; default: return 8; } break; default: return 8; } } EXPORT_SYMBOL(drm_dp_downstream_max_bpc); /** * drm_dp_downstream_420_passthrough() - determine downstream facing port * YCbCr 4:2:0 pass-through capability * @dpcd: DisplayPort configuration data * @port_cap: downstream facing port capabilities * * Returns: whether the downstream facing port can pass through YCbCr 4:2:0 */ bool drm_dp_downstream_420_passthrough(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4]) { if (!drm_dp_is_branch(dpcd)) return false; if (dpcd[DP_DPCD_REV] < 0x13) return false; switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) { case DP_DS_PORT_TYPE_DP: return true; case DP_DS_PORT_TYPE_HDMI: if ((dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE) == 0) return false; return port_cap[3] & DP_DS_HDMI_YCBCR420_PASS_THROUGH; default: return false; } } EXPORT_SYMBOL(drm_dp_downstream_420_passthrough); /** * drm_dp_downstream_444_to_420_conversion() - determine downstream facing port * YCbCr 4:4:4->4:2:0 conversion capability * @dpcd: DisplayPort configuration data * @port_cap: downstream facing port capabilities * * Returns: whether the downstream facing port can convert YCbCr 4:4:4 to 4:2:0 */ bool drm_dp_downstream_444_to_420_conversion(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4]) { if (!drm_dp_is_branch(dpcd)) return false; if (dpcd[DP_DPCD_REV] < 0x13) return false; switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) { case DP_DS_PORT_TYPE_HDMI: if ((dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE) == 0) return false; return port_cap[3] & DP_DS_HDMI_YCBCR444_TO_420_CONV; default: return false; } } EXPORT_SYMBOL(drm_dp_downstream_444_to_420_conversion); /** * drm_dp_downstream_rgb_to_ycbcr_conversion() - determine downstream facing port * RGB->YCbCr conversion capability * @dpcd: DisplayPort configuration data * @port_cap: downstream facing port capabilities * @color_spc: Colorspace for which conversion cap is sought * * Returns: whether the downstream facing port can convert RGB->YCbCr for a given * colorspace. */ bool drm_dp_downstream_rgb_to_ycbcr_conversion(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4], u8 color_spc) { if (!drm_dp_is_branch(dpcd)) return false; if (dpcd[DP_DPCD_REV] < 0x13) return false; switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) { case DP_DS_PORT_TYPE_HDMI: if ((dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE) == 0) return false; return port_cap[3] & color_spc; default: return false; } } EXPORT_SYMBOL(drm_dp_downstream_rgb_to_ycbcr_conversion); /** * drm_dp_downstream_mode() - return a mode for downstream facing port * @dev: DRM device * @dpcd: DisplayPort configuration data * @port_cap: port capabilities * * Provides a suitable mode for downstream facing ports without EDID. * * Returns: A new drm_display_mode on success or NULL on failure */ struct drm_display_mode * drm_dp_downstream_mode(struct drm_device *dev, const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4]) { u8 vic; if (!drm_dp_is_branch(dpcd)) return NULL; if (dpcd[DP_DPCD_REV] < 0x11) return NULL; switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) { case DP_DS_PORT_TYPE_NON_EDID: switch (port_cap[0] & DP_DS_NON_EDID_MASK) { case DP_DS_NON_EDID_720x480i_60: vic = 6; break; case DP_DS_NON_EDID_720x480i_50: vic = 21; break; case DP_DS_NON_EDID_1920x1080i_60: vic = 5; break; case DP_DS_NON_EDID_1920x1080i_50: vic = 20; break; case DP_DS_NON_EDID_1280x720_60: vic = 4; break; case DP_DS_NON_EDID_1280x720_50: vic = 19; break; default: return NULL; } return drm_display_mode_from_cea_vic(dev, vic); default: return NULL; } } EXPORT_SYMBOL(drm_dp_downstream_mode); /** * drm_dp_downstream_id() - identify branch device * @aux: DisplayPort AUX channel * @id: DisplayPort branch device id * * Returns branch device id on success or NULL on failure */ int drm_dp_downstream_id(struct drm_dp_aux *aux, char id[6]) { return drm_dp_dpcd_read(aux, DP_BRANCH_ID, id, 6); } EXPORT_SYMBOL(drm_dp_downstream_id); /** * drm_dp_downstream_debug() - debug DP branch devices * @m: pointer for debugfs file * @dpcd: DisplayPort configuration data * @port_cap: port capabilities * @edid: EDID * @aux: DisplayPort AUX channel * */ void drm_dp_downstream_debug(struct seq_file *m, const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4], const struct edid *edid, struct drm_dp_aux *aux) { bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE; int clk; int bpc; char id[7]; int len; uint8_t rev[2]; int type = port_cap[0] & DP_DS_PORT_TYPE_MASK; bool branch_device = drm_dp_is_branch(dpcd); seq_printf(m, "\tDP branch device present: %s\n", branch_device ? "yes" : "no"); if (!branch_device) return; switch (type) { case DP_DS_PORT_TYPE_DP: seq_puts(m, "\t\tType: DisplayPort\n"); break; case DP_DS_PORT_TYPE_VGA: seq_puts(m, "\t\tType: VGA\n"); break; case DP_DS_PORT_TYPE_DVI: seq_puts(m, "\t\tType: DVI\n"); break; case DP_DS_PORT_TYPE_HDMI: seq_puts(m, "\t\tType: HDMI\n"); break; case DP_DS_PORT_TYPE_NON_EDID: seq_puts(m, "\t\tType: others without EDID support\n"); break; case DP_DS_PORT_TYPE_DP_DUALMODE: seq_puts(m, "\t\tType: DP++\n"); break; case DP_DS_PORT_TYPE_WIRELESS: seq_puts(m, "\t\tType: Wireless\n"); break; default: seq_puts(m, "\t\tType: N/A\n"); } memset(id, 0, sizeof(id)); drm_dp_downstream_id(aux, id); seq_printf(m, "\t\tID: %s\n", id); len = drm_dp_dpcd_read(aux, DP_BRANCH_HW_REV, &rev[0], 1); if (len > 0) seq_printf(m, "\t\tHW: %d.%d\n", (rev[0] & 0xf0) >> 4, rev[0] & 0xf); len = drm_dp_dpcd_read(aux, DP_BRANCH_SW_REV, rev, 2); if (len > 0) seq_printf(m, "\t\tSW: %d.%d\n", rev[0], rev[1]); if (detailed_cap_info) { clk = drm_dp_downstream_max_dotclock(dpcd, port_cap); if (clk > 0) seq_printf(m, "\t\tMax dot clock: %d kHz\n", clk); clk = drm_dp_downstream_max_tmds_clock(dpcd, port_cap, edid); if (clk > 0) seq_printf(m, "\t\tMax TMDS clock: %d kHz\n", clk); clk = drm_dp_downstream_min_tmds_clock(dpcd, port_cap, edid); if (clk > 0) seq_printf(m, "\t\tMin TMDS clock: %d kHz\n", clk); bpc = drm_dp_downstream_max_bpc(dpcd, port_cap, edid); if (bpc > 0) seq_printf(m, "\t\tMax bpc: %d\n", bpc); } } EXPORT_SYMBOL(drm_dp_downstream_debug); /** * drm_dp_subconnector_type() - get DP branch device type * @dpcd: DisplayPort configuration data * @port_cap: port capabilities */ enum drm_mode_subconnector drm_dp_subconnector_type(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4]) { int type; if (!drm_dp_is_branch(dpcd)) return DRM_MODE_SUBCONNECTOR_Native; /* DP 1.0 approach */ if (dpcd[DP_DPCD_REV] == DP_DPCD_REV_10) { type = dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK; switch (type) { case DP_DWN_STRM_PORT_TYPE_TMDS: /* Can be HDMI or DVI-D, DVI-D is a safer option */ return DRM_MODE_SUBCONNECTOR_DVID; case DP_DWN_STRM_PORT_TYPE_ANALOG: /* Can be VGA or DVI-A, VGA is more popular */ return DRM_MODE_SUBCONNECTOR_VGA; case DP_DWN_STRM_PORT_TYPE_DP: return DRM_MODE_SUBCONNECTOR_DisplayPort; case DP_DWN_STRM_PORT_TYPE_OTHER: default: return DRM_MODE_SUBCONNECTOR_Unknown; } } type = port_cap[0] & DP_DS_PORT_TYPE_MASK; switch (type) { case DP_DS_PORT_TYPE_DP: case DP_DS_PORT_TYPE_DP_DUALMODE: return DRM_MODE_SUBCONNECTOR_DisplayPort; case DP_DS_PORT_TYPE_VGA: return DRM_MODE_SUBCONNECTOR_VGA; case DP_DS_PORT_TYPE_DVI: return DRM_MODE_SUBCONNECTOR_DVID; case DP_DS_PORT_TYPE_HDMI: return DRM_MODE_SUBCONNECTOR_HDMIA; case DP_DS_PORT_TYPE_WIRELESS: return DRM_MODE_SUBCONNECTOR_Wireless; case DP_DS_PORT_TYPE_NON_EDID: default: return DRM_MODE_SUBCONNECTOR_Unknown; } } EXPORT_SYMBOL(drm_dp_subconnector_type); /** * drm_dp_set_subconnector_property - set subconnector for DP connector * @connector: connector to set property on * @status: connector status * @dpcd: DisplayPort configuration data * @port_cap: port capabilities * * Called by a driver on every detect event. */ void drm_dp_set_subconnector_property(struct drm_connector *connector, enum drm_connector_status status, const u8 *dpcd, const u8 port_cap[4]) { enum drm_mode_subconnector subconnector = DRM_MODE_SUBCONNECTOR_Unknown; if (status == connector_status_connected) subconnector = drm_dp_subconnector_type(dpcd, port_cap); drm_object_property_set_value(&connector->base, connector->dev->mode_config.dp_subconnector_property, subconnector); } EXPORT_SYMBOL(drm_dp_set_subconnector_property); /** * drm_dp_read_sink_count_cap() - Check whether a given connector has a valid sink * count * @connector: The DRM connector to check * @dpcd: A cached copy of the connector's DPCD RX capabilities * @desc: A cached copy of the connector's DP descriptor * * See also: drm_dp_read_sink_count() * * Returns: %True if the (e)DP connector has a valid sink count that should * be probed, %false otherwise. */ bool drm_dp_read_sink_count_cap(struct drm_connector *connector, const u8 dpcd[DP_RECEIVER_CAP_SIZE], const struct drm_dp_desc *desc) { /* Some eDP panels don't set a valid value for the sink count */ return connector->connector_type != DRM_MODE_CONNECTOR_eDP && dpcd[DP_DPCD_REV] >= DP_DPCD_REV_11 && dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT && !drm_dp_has_quirk(desc, DP_DPCD_QUIRK_NO_SINK_COUNT); } EXPORT_SYMBOL(drm_dp_read_sink_count_cap); /** * drm_dp_read_sink_count() - Retrieve the sink count for a given sink * @aux: The DP AUX channel to use * * See also: drm_dp_read_sink_count_cap() * * Returns: The current sink count reported by @aux, or a negative error code * otherwise. */ int drm_dp_read_sink_count(struct drm_dp_aux *aux) { u8 count; int ret; ret = drm_dp_dpcd_readb(aux, DP_SINK_COUNT, &count); if (ret < 0) return ret; if (ret != 1) return -EIO; return DP_GET_SINK_COUNT(count); } EXPORT_SYMBOL(drm_dp_read_sink_count); /* * I2C-over-AUX implementation */ static u32 drm_dp_i2c_functionality(struct i2c_adapter *adapter) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | I2C_FUNC_10BIT_ADDR; } static void drm_dp_i2c_msg_write_status_update(struct drm_dp_aux_msg *msg) { /* * In case of i2c defer or short i2c ack reply to a write, * we need to switch to WRITE_STATUS_UPDATE to drain the * rest of the message */ if ((msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_I2C_WRITE) { msg->request &= DP_AUX_I2C_MOT; msg->request |= DP_AUX_I2C_WRITE_STATUS_UPDATE; } } #define AUX_PRECHARGE_LEN 10 /* 10 to 16 */ #define AUX_SYNC_LEN (16 + 4) /* preamble + AUX_SYNC_END */ #define AUX_STOP_LEN 4 #define AUX_CMD_LEN 4 #define AUX_ADDRESS_LEN 20 #define AUX_REPLY_PAD_LEN 4 #define AUX_LENGTH_LEN 8 /* * Calculate the duration of the AUX request/reply in usec. Gives the * "best" case estimate, ie. successful while as short as possible. */ static int drm_dp_aux_req_duration(const struct drm_dp_aux_msg *msg) { int len = AUX_PRECHARGE_LEN + AUX_SYNC_LEN + AUX_STOP_LEN + AUX_CMD_LEN + AUX_ADDRESS_LEN + AUX_LENGTH_LEN; if ((msg->request & DP_AUX_I2C_READ) == 0) len += msg->size * 8; return len; } static int drm_dp_aux_reply_duration(const struct drm_dp_aux_msg *msg) { int len = AUX_PRECHARGE_LEN + AUX_SYNC_LEN + AUX_STOP_LEN + AUX_CMD_LEN + AUX_REPLY_PAD_LEN; /* * For read we expect what was asked. For writes there will * be 0 or 1 data bytes. Assume 0 for the "best" case. */ if (msg->request & DP_AUX_I2C_READ) len += msg->size * 8; return len; } #define I2C_START_LEN 1 #define I2C_STOP_LEN 1 #define I2C_ADDR_LEN 9 /* ADDRESS + R/W + ACK/NACK */ #define I2C_DATA_LEN 9 /* DATA + ACK/NACK */ /* * Calculate the length of the i2c transfer in usec, assuming * the i2c bus speed is as specified. Gives the the "worst" * case estimate, ie. successful while as long as possible. * Doesn't account the the "MOT" bit, and instead assumes each * message includes a START, ADDRESS and STOP. Neither does it * account for additional random variables such as clock stretching. */ static int drm_dp_i2c_msg_duration(const struct drm_dp_aux_msg *msg, int i2c_speed_khz) { /* AUX bitrate is 1MHz, i2c bitrate as specified */ return DIV_ROUND_UP((I2C_START_LEN + I2C_ADDR_LEN + msg->size * I2C_DATA_LEN + I2C_STOP_LEN) * 1000, i2c_speed_khz); } /* * Determine how many retries should be attempted to successfully transfer * the specified message, based on the estimated durations of the * i2c and AUX transfers. */ static int drm_dp_i2c_retry_count(const struct drm_dp_aux_msg *msg, int i2c_speed_khz) { int aux_time_us = drm_dp_aux_req_duration(msg) + drm_dp_aux_reply_duration(msg); int i2c_time_us = drm_dp_i2c_msg_duration(msg, i2c_speed_khz); return DIV_ROUND_UP(i2c_time_us, aux_time_us + AUX_RETRY_INTERVAL); } /* * FIXME currently assumes 10 kHz as some real world devices seem * to require it. We should query/set the speed via DPCD if supported. */ static int dp_aux_i2c_speed_khz __read_mostly = 10; module_param_unsafe(dp_aux_i2c_speed_khz, int, 0644); MODULE_PARM_DESC(dp_aux_i2c_speed_khz, "Assumed speed of the i2c bus in kHz, (1-400, default 10)"); /* * Transfer a single I2C-over-AUX message and handle various error conditions, * retrying the transaction as appropriate. It is assumed that the * &drm_dp_aux.transfer function does not modify anything in the msg other than the * reply field. * * Returns bytes transferred on success, or a negative error code on failure. */ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) { unsigned int retry, defer_i2c; int ret; /* * DP1.2 sections 2.7.7.1.5.6.1 and 2.7.7.1.6.6.1: A DP Source device * is required to retry at least seven times upon receiving AUX_DEFER * before giving up the AUX transaction. * * We also try to account for the i2c bus speed. */ int max_retries = max(7, drm_dp_i2c_retry_count(msg, dp_aux_i2c_speed_khz)); for (retry = 0, defer_i2c = 0; retry < (max_retries + defer_i2c); retry++) { ret = aux->transfer(aux, msg); if (ret < 0) { if (ret == -EBUSY) continue; /* * While timeouts can be errors, they're usually normal * behavior (for instance, when a driver tries to * communicate with a non-existent DisplayPort device). * Avoid spamming the kernel log with timeout errors. */ if (ret == -ETIMEDOUT) drm_dbg_kms_ratelimited(aux->drm_dev, "%s: transaction timed out\n", aux->name); else drm_dbg_kms(aux->drm_dev, "%s: transaction failed: %d\n", aux->name, ret); return ret; } switch (msg->reply & DP_AUX_NATIVE_REPLY_MASK) { case DP_AUX_NATIVE_REPLY_ACK: /* * For I2C-over-AUX transactions this isn't enough, we * need to check for the I2C ACK reply. */ break; case DP_AUX_NATIVE_REPLY_NACK: drm_dbg_kms(aux->drm_dev, "%s: native nack (result=%d, size=%zu)\n", aux->name, ret, msg->size); return -EREMOTEIO; case DP_AUX_NATIVE_REPLY_DEFER: drm_dbg_kms(aux->drm_dev, "%s: native defer\n", aux->name); /* * We could check for I2C bit rate capabilities and if * available adjust this interval. We could also be * more careful with DP-to-legacy adapters where a * long legacy cable may force very low I2C bit rates. * * For now just defer for long enough to hopefully be * safe for all use-cases. */ usleep_range(AUX_RETRY_INTERVAL, AUX_RETRY_INTERVAL + 100); continue; default: drm_err(aux->drm_dev, "%s: invalid native reply %#04x\n", aux->name, msg->reply); return -EREMOTEIO; } switch (msg->reply & DP_AUX_I2C_REPLY_MASK) { case DP_AUX_I2C_REPLY_ACK: /* * Both native ACK and I2C ACK replies received. We * can assume the transfer was successful. */ if (ret != msg->size) drm_dp_i2c_msg_write_status_update(msg); return ret; case DP_AUX_I2C_REPLY_NACK: drm_dbg_kms(aux->drm_dev, "%s: I2C nack (result=%d, size=%zu)\n", aux->name, ret, msg->size); aux->i2c_nack_count++; return -EREMOTEIO; case DP_AUX_I2C_REPLY_DEFER: drm_dbg_kms(aux->drm_dev, "%s: I2C defer\n", aux->name); /* DP Compliance Test 4.2.2.5 Requirement: * Must have at least 7 retries for I2C defers on the * transaction to pass this test */ aux->i2c_defer_count++; if (defer_i2c < 7) defer_i2c++; usleep_range(AUX_RETRY_INTERVAL, AUX_RETRY_INTERVAL + 100); drm_dp_i2c_msg_write_status_update(msg); continue; default: drm_err(aux->drm_dev, "%s: invalid I2C reply %#04x\n", aux->name, msg->reply); return -EREMOTEIO; } } drm_dbg_kms(aux->drm_dev, "%s: Too many retries, giving up\n", aux->name); return -EREMOTEIO; } static void drm_dp_i2c_msg_set_request(struct drm_dp_aux_msg *msg, const struct i2c_msg *i2c_msg) { msg->request = (i2c_msg->flags & I2C_M_RD) ? DP_AUX_I2C_READ : DP_AUX_I2C_WRITE; if (!(i2c_msg->flags & I2C_M_STOP)) msg->request |= DP_AUX_I2C_MOT; } /* * Keep retrying drm_dp_i2c_do_msg until all data has been transferred. * * Returns an error code on failure, or a recommended transfer size on success. */ static int drm_dp_i2c_drain_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *orig_msg) { int err, ret = orig_msg->size; struct drm_dp_aux_msg msg = *orig_msg; while (msg.size > 0) { err = drm_dp_i2c_do_msg(aux, &msg); if (err <= 0) return err == 0 ? -EPROTO : err; if (err < msg.size && err < ret) { drm_dbg_kms(aux->drm_dev, "%s: Partial I2C reply: requested %zu bytes got %d bytes\n", aux->name, msg.size, err); ret = err; } msg.size -= err; msg.buffer += err; } return ret; } /* * Bizlink designed DP->DVI-D Dual Link adapters require the I2C over AUX * packets to be as large as possible. If not, the I2C transactions never * succeed. Hence the default is maximum. */ static int dp_aux_i2c_transfer_size __read_mostly = DP_AUX_MAX_PAYLOAD_BYTES; module_param_unsafe(dp_aux_i2c_transfer_size, int, 0644); MODULE_PARM_DESC(dp_aux_i2c_transfer_size, "Number of bytes to transfer in a single I2C over DP AUX CH message, (1-16, default 16)"); static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) { struct drm_dp_aux *aux = adapter->algo_data; unsigned int i, j; unsigned transfer_size; struct drm_dp_aux_msg msg; int err = 0; dp_aux_i2c_transfer_size = clamp(dp_aux_i2c_transfer_size, 1, DP_AUX_MAX_PAYLOAD_BYTES); memset(&msg, 0, sizeof(msg)); for (i = 0; i < num; i++) { msg.address = msgs[i].addr; drm_dp_i2c_msg_set_request(&msg, &msgs[i]); /* Send a bare address packet to start the transaction. * Zero sized messages specify an address only (bare * address) transaction. */ msg.buffer = NULL; msg.size = 0; err = drm_dp_i2c_do_msg(aux, &msg); /* * Reset msg.request in case in case it got * changed into a WRITE_STATUS_UPDATE. */ drm_dp_i2c_msg_set_request(&msg, &msgs[i]); if (err < 0) break; /* We want each transaction to be as large as possible, but * we'll go to smaller sizes if the hardware gives us a * short reply. */ transfer_size = dp_aux_i2c_transfer_size; for (j = 0; j < msgs[i].len; j += msg.size) { msg.buffer = msgs[i].buf + j; msg.size = min(transfer_size, msgs[i].len - j); err = drm_dp_i2c_drain_msg(aux, &msg); /* * Reset msg.request in case in case it got * changed into a WRITE_STATUS_UPDATE. */ drm_dp_i2c_msg_set_request(&msg, &msgs[i]); if (err < 0) break; transfer_size = err; } if (err < 0) break; } if (err >= 0) err = num; /* Send a bare address packet to close out the transaction. * Zero sized messages specify an address only (bare * address) transaction. */ msg.request &= ~DP_AUX_I2C_MOT; msg.buffer = NULL; msg.size = 0; (void)drm_dp_i2c_do_msg(aux, &msg); return err; } static const struct i2c_algorithm drm_dp_i2c_algo = { .functionality = drm_dp_i2c_functionality, .master_xfer = drm_dp_i2c_xfer, }; static struct drm_dp_aux *i2c_to_aux(struct i2c_adapter *i2c) { return container_of(i2c, struct drm_dp_aux, ddc); } static void lock_bus(struct i2c_adapter *i2c, unsigned int flags) { mutex_lock(&i2c_to_aux(i2c)->hw_mutex); } static int trylock_bus(struct i2c_adapter *i2c, unsigned int flags) { return mutex_trylock(&i2c_to_aux(i2c)->hw_mutex); } static void unlock_bus(struct i2c_adapter *i2c, unsigned int flags) { mutex_unlock(&i2c_to_aux(i2c)->hw_mutex); } static const struct i2c_lock_operations drm_dp_i2c_lock_ops = { .lock_bus = lock_bus, .trylock_bus = trylock_bus, .unlock_bus = unlock_bus, }; static int drm_dp_aux_get_crc(struct drm_dp_aux *aux, u8 *crc) { u8 buf, count; int ret; ret = drm_dp_dpcd_readb(aux, DP_TEST_SINK, &buf); if (ret < 0) return ret; WARN_ON(!(buf & DP_TEST_SINK_START)); ret = drm_dp_dpcd_readb(aux, DP_TEST_SINK_MISC, &buf); if (ret < 0) return ret; count = buf & DP_TEST_COUNT_MASK; if (count == aux->crc_count) return -EAGAIN; /* No CRC yet */ aux->crc_count = count; /* * At DP_TEST_CRC_R_CR, there's 6 bytes containing CRC data, 2 bytes * per component (RGB or CrYCb). */ ret = drm_dp_dpcd_read(aux, DP_TEST_CRC_R_CR, crc, 6); if (ret < 0) return ret; return 0; } static void drm_dp_aux_crc_work(struct work_struct *work) { struct drm_dp_aux *aux = container_of(work, struct drm_dp_aux, crc_work); struct drm_crtc *crtc; u8 crc_bytes[6]; uint32_t crcs[3]; int ret; if (WARN_ON(!aux->crtc)) return; crtc = aux->crtc; while (crtc->crc.opened) { drm_crtc_wait_one_vblank(crtc); if (!crtc->crc.opened) break; ret = drm_dp_aux_get_crc(aux, crc_bytes); if (ret == -EAGAIN) { usleep_range(1000, 2000); ret = drm_dp_aux_get_crc(aux, crc_bytes); } if (ret == -EAGAIN) { drm_dbg_kms(aux->drm_dev, "%s: Get CRC failed after retrying: %d\n", aux->name, ret); continue; } else if (ret) { drm_dbg_kms(aux->drm_dev, "%s: Failed to get a CRC: %d\n", aux->name, ret); continue; } crcs[0] = crc_bytes[0] | crc_bytes[1] << 8; crcs[1] = crc_bytes[2] | crc_bytes[3] << 8; crcs[2] = crc_bytes[4] | crc_bytes[5] << 8; drm_crtc_add_crc_entry(crtc, false, 0, crcs); } } /** * drm_dp_remote_aux_init() - minimally initialise a remote aux channel * @aux: DisplayPort AUX channel * * Used for remote aux channel in general. Merely initialize the crc work * struct. */ void drm_dp_remote_aux_init(struct drm_dp_aux *aux) { INIT_WORK(&aux->crc_work, drm_dp_aux_crc_work); } EXPORT_SYMBOL(drm_dp_remote_aux_init); /** * drm_dp_aux_init() - minimally initialise an aux channel * @aux: DisplayPort AUX channel * * If you need to use the drm_dp_aux's i2c adapter prior to registering it with * the outside world, call drm_dp_aux_init() first. For drivers which are * grandparents to their AUX adapters (e.g. the AUX adapter is parented by a * &drm_connector), you must still call drm_dp_aux_register() once the connector * has been registered to allow userspace access to the auxiliary DP channel. * Likewise, for such drivers you should also assign &drm_dp_aux.drm_dev as * early as possible so that the &drm_device that corresponds to the AUX adapter * may be mentioned in debugging output from the DRM DP helpers. * * For devices which use a separate platform device for their AUX adapters, this * may be called as early as required by the driver. * */ void drm_dp_aux_init(struct drm_dp_aux *aux) { mutex_init(&aux->hw_mutex); mutex_init(&aux->cec.lock); INIT_WORK(&aux->crc_work, drm_dp_aux_crc_work); aux->ddc.algo = &drm_dp_i2c_algo; aux->ddc.algo_data = aux; aux->ddc.retries = 3; aux->ddc.lock_ops = &drm_dp_i2c_lock_ops; } EXPORT_SYMBOL(drm_dp_aux_init); /** * drm_dp_aux_register() - initialise and register aux channel * @aux: DisplayPort AUX channel * * Automatically calls drm_dp_aux_init() if this hasn't been done yet. This * should only be called once the parent of @aux, &drm_dp_aux.dev, is * initialized. For devices which are grandparents of their AUX channels, * &drm_dp_aux.dev will typically be the &drm_connector &device which * corresponds to @aux. For these devices, it's advised to call * drm_dp_aux_register() in &drm_connector_funcs.late_register, and likewise to * call drm_dp_aux_unregister() in &drm_connector_funcs.early_unregister. * Functions which don't follow this will likely Oops when * %CONFIG_DRM_DP_AUX_CHARDEV is enabled. * * For devices where the AUX channel is a device that exists independently of * the &drm_device that uses it, such as SoCs and bridge devices, it is * recommended to call drm_dp_aux_register() after a &drm_device has been * assigned to &drm_dp_aux.drm_dev, and likewise to call * drm_dp_aux_unregister() once the &drm_device should no longer be associated * with the AUX channel (e.g. on bridge detach). * * Drivers which need to use the aux channel before either of the two points * mentioned above need to call drm_dp_aux_init() in order to use the AUX * channel before registration. * * Returns 0 on success or a negative error code on failure. */ int drm_dp_aux_register(struct drm_dp_aux *aux) { int ret; WARN_ON_ONCE(!aux->drm_dev); if (!aux->ddc.algo) drm_dp_aux_init(aux); aux->ddc.class = I2C_CLASS_DDC; aux->ddc.owner = THIS_MODULE; aux->ddc.dev.parent = aux->dev; strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev), sizeof(aux->ddc.name)); ret = drm_dp_aux_register_devnode(aux); if (ret) return ret; ret = i2c_add_adapter(&aux->ddc); if (ret) { drm_dp_aux_unregister_devnode(aux); return ret; } return 0; } EXPORT_SYMBOL(drm_dp_aux_register); /** * drm_dp_aux_unregister() - unregister an AUX adapter * @aux: DisplayPort AUX channel */ void drm_dp_aux_unregister(struct drm_dp_aux *aux) { drm_dp_aux_unregister_devnode(aux); i2c_del_adapter(&aux->ddc); } EXPORT_SYMBOL(drm_dp_aux_unregister); #define PSR_SETUP_TIME(x) [DP_PSR_SETUP_TIME_ ## x >> DP_PSR_SETUP_TIME_SHIFT] = (x) /** * drm_dp_psr_setup_time() - PSR setup in time usec * @psr_cap: PSR capabilities from DPCD * * Returns: * PSR setup time for the panel in microseconds, negative * error code on failure. */ int drm_dp_psr_setup_time(const u8 psr_cap[EDP_PSR_RECEIVER_CAP_SIZE]) { static const u16 psr_setup_time_us[] = { PSR_SETUP_TIME(330), PSR_SETUP_TIME(275), PSR_SETUP_TIME(220), PSR_SETUP_TIME(165), PSR_SETUP_TIME(110), PSR_SETUP_TIME(55), PSR_SETUP_TIME(0), }; int i; i = (psr_cap[1] & DP_PSR_SETUP_TIME_MASK) >> DP_PSR_SETUP_TIME_SHIFT; if (i >= ARRAY_SIZE(psr_setup_time_us)) return -EINVAL; return psr_setup_time_us[i]; } EXPORT_SYMBOL(drm_dp_psr_setup_time); #undef PSR_SETUP_TIME /** * drm_dp_start_crc() - start capture of frame CRCs * @aux: DisplayPort AUX channel * @crtc: CRTC displaying the frames whose CRCs are to be captured * * Returns 0 on success or a negative error code on failure. */ int drm_dp_start_crc(struct drm_dp_aux *aux, struct drm_crtc *crtc) { u8 buf; int ret; ret = drm_dp_dpcd_readb(aux, DP_TEST_SINK, &buf); if (ret < 0) return ret; ret = drm_dp_dpcd_writeb(aux, DP_TEST_SINK, buf | DP_TEST_SINK_START); if (ret < 0) return ret; aux->crc_count = 0; aux->crtc = crtc; schedule_work(&aux->crc_work); return 0; } EXPORT_SYMBOL(drm_dp_start_crc); /** * drm_dp_stop_crc() - stop capture of frame CRCs * @aux: DisplayPort AUX channel * * Returns 0 on success or a negative error code on failure. */ int drm_dp_stop_crc(struct drm_dp_aux *aux) { u8 buf; int ret; ret = drm_dp_dpcd_readb(aux, DP_TEST_SINK, &buf); if (ret < 0) return ret; ret = drm_dp_dpcd_writeb(aux, DP_TEST_SINK, buf & ~DP_TEST_SINK_START); if (ret < 0) return ret; flush_work(&aux->crc_work); aux->crtc = NULL; return 0; } EXPORT_SYMBOL(drm_dp_stop_crc); struct dpcd_quirk { u8 oui[3]; u8 device_id[6]; bool is_branch; u32 quirks; }; #define OUI(first, second, third) { (first), (second), (third) } #define DEVICE_ID(first, second, third, fourth, fifth, sixth) \ { (first), (second), (third), (fourth), (fifth), (sixth) } #define DEVICE_ID_ANY DEVICE_ID(0, 0, 0, 0, 0, 0) static const struct dpcd_quirk dpcd_quirk_list[] = { /* Analogix 7737 needs reduced M and N at HBR2 link rates */ { OUI(0x00, 0x22, 0xb9), DEVICE_ID_ANY, true, BIT(DP_DPCD_QUIRK_CONSTANT_N) }, /* LG LP140WF6-SPM1 eDP panel */ { OUI(0x00, 0x22, 0xb9), DEVICE_ID('s', 'i', 'v', 'a', 'r', 'T'), false, BIT(DP_DPCD_QUIRK_CONSTANT_N) }, /* Apple panels need some additional handling to support PSR */ { OUI(0x00, 0x10, 0xfa), DEVICE_ID_ANY, false, BIT(DP_DPCD_QUIRK_NO_PSR) }, /* CH7511 seems to leave SINK_COUNT zeroed */ { OUI(0x00, 0x00, 0x00), DEVICE_ID('C', 'H', '7', '5', '1', '1'), false, BIT(DP_DPCD_QUIRK_NO_SINK_COUNT) }, /* Synaptics DP1.4 MST hubs can support DSC without virtual DPCD */ { OUI(0x90, 0xCC, 0x24), DEVICE_ID_ANY, true, BIT(DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) }, /* Apple MacBookPro 2017 15 inch eDP Retina panel reports too low DP_MAX_LINK_RATE */ { OUI(0x00, 0x10, 0xfa), DEVICE_ID(101, 68, 21, 101, 98, 97), false, BIT(DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS) }, }; #undef OUI /* * Get a bit mask of DPCD quirks for the sink/branch device identified by * ident. The quirk data is shared but it's up to the drivers to act on the * data. * * For now, only the OUI (first three bytes) is used, but this may be extended * to device identification string and hardware/firmware revisions later. */ static u32 drm_dp_get_quirks(const struct drm_dp_dpcd_ident *ident, bool is_branch) { const struct dpcd_quirk *quirk; u32 quirks = 0; int i; u8 any_device[] = DEVICE_ID_ANY; for (i = 0; i < ARRAY_SIZE(dpcd_quirk_list); i++) { quirk = &dpcd_quirk_list[i]; if (quirk->is_branch != is_branch) continue; if (memcmp(quirk->oui, ident->oui, sizeof(ident->oui)) != 0) continue; if (memcmp(quirk->device_id, any_device, sizeof(any_device)) != 0 && memcmp(quirk->device_id, ident->device_id, sizeof(ident->device_id)) != 0) continue; quirks |= quirk->quirks; } return quirks; } #undef DEVICE_ID_ANY #undef DEVICE_ID /** * drm_dp_read_desc - read sink/branch descriptor from DPCD * @aux: DisplayPort AUX channel * @desc: Device descriptor to fill from DPCD * @is_branch: true for branch devices, false for sink devices * * Read DPCD 0x400 (sink) or 0x500 (branch) into @desc. Also debug log the * identification. * * Returns 0 on success or a negative error code on failure. */ int drm_dp_read_desc(struct drm_dp_aux *aux, struct drm_dp_desc *desc, bool is_branch) { struct drm_dp_dpcd_ident *ident = &desc->ident; unsigned int offset = is_branch ? DP_BRANCH_OUI : DP_SINK_OUI; int ret, dev_id_len; ret = drm_dp_dpcd_read(aux, offset, ident, sizeof(*ident)); if (ret < 0) return ret; desc->quirks = drm_dp_get_quirks(ident, is_branch); dev_id_len = strnlen(ident->device_id, sizeof(ident->device_id)); drm_dbg_kms(aux->drm_dev, "%s: DP %s: OUI %*phD dev-ID %*pE HW-rev %d.%d SW-rev %d.%d quirks 0x%04x\n", aux->name, is_branch ? "branch" : "sink", (int)sizeof(ident->oui), ident->oui, dev_id_len, ident->device_id, ident->hw_rev >> 4, ident->hw_rev & 0xf, ident->sw_major_rev, ident->sw_minor_rev, desc->quirks); return 0; } EXPORT_SYMBOL(drm_dp_read_desc); /** * drm_dp_dsc_sink_max_slice_count() - Get the max slice count * supported by the DSC sink. * @dsc_dpcd: DSC capabilities from DPCD * @is_edp: true if its eDP, false for DP * * Read the slice capabilities DPCD register from DSC sink to get * the maximum slice count supported. This is used to populate * the DSC parameters in the &struct drm_dsc_config by the driver. * Driver creates an infoframe using these parameters to populate * &struct drm_dsc_pps_infoframe. These are sent to the sink using DSC * infoframe using the helper function drm_dsc_pps_infoframe_pack() * * Returns: * Maximum slice count supported by DSC sink or 0 its invalid */ u8 drm_dp_dsc_sink_max_slice_count(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE], bool is_edp) { u8 slice_cap1 = dsc_dpcd[DP_DSC_SLICE_CAP_1 - DP_DSC_SUPPORT]; if (is_edp) { /* For eDP, register DSC_SLICE_CAPABILITIES_1 gives slice count */ if (slice_cap1 & DP_DSC_4_PER_DP_DSC_SINK) return 4; if (slice_cap1 & DP_DSC_2_PER_DP_DSC_SINK) return 2; if (slice_cap1 & DP_DSC_1_PER_DP_DSC_SINK) return 1; } else { /* For DP, use values from DSC_SLICE_CAP_1 and DSC_SLICE_CAP2 */ u8 slice_cap2 = dsc_dpcd[DP_DSC_SLICE_CAP_2 - DP_DSC_SUPPORT]; if (slice_cap2 & DP_DSC_24_PER_DP_DSC_SINK) return 24; if (slice_cap2 & DP_DSC_20_PER_DP_DSC_SINK) return 20; if (slice_cap2 & DP_DSC_16_PER_DP_DSC_SINK) return 16; if (slice_cap1 & DP_DSC_12_PER_DP_DSC_SINK) return 12; if (slice_cap1 & DP_DSC_10_PER_DP_DSC_SINK) return 10; if (slice_cap1 & DP_DSC_8_PER_DP_DSC_SINK) return 8; if (slice_cap1 & DP_DSC_6_PER_DP_DSC_SINK) return 6; if (slice_cap1 & DP_DSC_4_PER_DP_DSC_SINK) return 4; if (slice_cap1 & DP_DSC_2_PER_DP_DSC_SINK) return 2; if (slice_cap1 & DP_DSC_1_PER_DP_DSC_SINK) return 1; } return 0; } EXPORT_SYMBOL(drm_dp_dsc_sink_max_slice_count); /** * drm_dp_dsc_sink_line_buf_depth() - Get the line buffer depth in bits * @dsc_dpcd: DSC capabilities from DPCD * * Read the DSC DPCD register to parse the line buffer depth in bits which is * number of bits of precision within the decoder line buffer supported by * the DSC sink. This is used to populate the DSC parameters in the * &struct drm_dsc_config by the driver. * Driver creates an infoframe using these parameters to populate * &struct drm_dsc_pps_infoframe. These are sent to the sink using DSC * infoframe using the helper function drm_dsc_pps_infoframe_pack() * * Returns: * Line buffer depth supported by DSC panel or 0 its invalid */ u8 drm_dp_dsc_sink_line_buf_depth(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE]) { u8 line_buf_depth = dsc_dpcd[DP_DSC_LINE_BUF_BIT_DEPTH - DP_DSC_SUPPORT]; switch (line_buf_depth & DP_DSC_LINE_BUF_BIT_DEPTH_MASK) { case DP_DSC_LINE_BUF_BIT_DEPTH_9: return 9; case DP_DSC_LINE_BUF_BIT_DEPTH_10: return 10; case DP_DSC_LINE_BUF_BIT_DEPTH_11: return 11; case DP_DSC_LINE_BUF_BIT_DEPTH_12: return 12; case DP_DSC_LINE_BUF_BIT_DEPTH_13: return 13; case DP_DSC_LINE_BUF_BIT_DEPTH_14: return 14; case DP_DSC_LINE_BUF_BIT_DEPTH_15: return 15; case DP_DSC_LINE_BUF_BIT_DEPTH_16: return 16; case DP_DSC_LINE_BUF_BIT_DEPTH_8: return 8; } return 0; } EXPORT_SYMBOL(drm_dp_dsc_sink_line_buf_depth); /** * drm_dp_dsc_sink_supported_input_bpcs() - Get all the input bits per component * values supported by the DSC sink. * @dsc_dpcd: DSC capabilities from DPCD * @dsc_bpc: An array to be filled by this helper with supported * input bpcs. * * Read the DSC DPCD from the sink device to parse the supported bits per * component values. This is used to populate the DSC parameters * in the &struct drm_dsc_config by the driver. * Driver creates an infoframe using these parameters to populate * &struct drm_dsc_pps_infoframe. These are sent to the sink using DSC * infoframe using the helper function drm_dsc_pps_infoframe_pack() * * Returns: * Number of input BPC values parsed from the DPCD */ int drm_dp_dsc_sink_supported_input_bpcs(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE], u8 dsc_bpc[3]) { int num_bpc = 0; u8 color_depth = dsc_dpcd[DP_DSC_DEC_COLOR_DEPTH_CAP - DP_DSC_SUPPORT]; if (color_depth & DP_DSC_12_BPC) dsc_bpc[num_bpc++] = 12; if (color_depth & DP_DSC_10_BPC) dsc_bpc[num_bpc++] = 10; if (color_depth & DP_DSC_8_BPC) dsc_bpc[num_bpc++] = 8; return num_bpc; } EXPORT_SYMBOL(drm_dp_dsc_sink_supported_input_bpcs); /** * drm_dp_read_lttpr_common_caps - read the LTTPR common capabilities * @aux: DisplayPort AUX channel * @caps: buffer to return the capability info in * * Read capabilities common to all LTTPRs. * * Returns 0 on success or a negative error code on failure. */ int drm_dp_read_lttpr_common_caps(struct drm_dp_aux *aux, u8 caps[DP_LTTPR_COMMON_CAP_SIZE]) { int ret; ret = drm_dp_dpcd_read(aux, DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV, caps, DP_LTTPR_COMMON_CAP_SIZE); if (ret < 0) return ret; WARN_ON(ret != DP_LTTPR_COMMON_CAP_SIZE); return 0; } EXPORT_SYMBOL(drm_dp_read_lttpr_common_caps); /** * drm_dp_read_lttpr_phy_caps - read the capabilities for a given LTTPR PHY * @aux: DisplayPort AUX channel * @dp_phy: LTTPR PHY to read the capabilities for * @caps: buffer to return the capability info in * * Read the capabilities for the given LTTPR PHY. * * Returns 0 on success or a negative error code on failure. */ int drm_dp_read_lttpr_phy_caps(struct drm_dp_aux *aux, enum drm_dp_phy dp_phy, u8 caps[DP_LTTPR_PHY_CAP_SIZE]) { int ret; ret = drm_dp_dpcd_read(aux, DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER(dp_phy), caps, DP_LTTPR_PHY_CAP_SIZE); if (ret < 0) return ret; WARN_ON(ret != DP_LTTPR_PHY_CAP_SIZE); return 0; } EXPORT_SYMBOL(drm_dp_read_lttpr_phy_caps); static u8 dp_lttpr_common_cap(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE], int r) { return caps[r - DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV]; } /** * drm_dp_lttpr_count - get the number of detected LTTPRs * @caps: LTTPR common capabilities * * Get the number of detected LTTPRs from the LTTPR common capabilities info. * * Returns: * -ERANGE if more than supported number (8) of LTTPRs are detected * -EINVAL if the DP_PHY_REPEATER_CNT register contains an invalid value * otherwise the number of detected LTTPRs */ int drm_dp_lttpr_count(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]) { u8 count = dp_lttpr_common_cap(caps, DP_PHY_REPEATER_CNT); switch (hweight8(count)) { case 0: return 0; case 1: return 8 - ilog2(count); case 8: return -ERANGE; default: return -EINVAL; } } EXPORT_SYMBOL(drm_dp_lttpr_count); /** * drm_dp_lttpr_max_link_rate - get the maximum link rate supported by all LTTPRs * @caps: LTTPR common capabilities * * Returns the maximum link rate supported by all detected LTTPRs. */ int drm_dp_lttpr_max_link_rate(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]) { u8 rate = dp_lttpr_common_cap(caps, DP_MAX_LINK_RATE_PHY_REPEATER); return drm_dp_bw_code_to_link_rate(rate); } EXPORT_SYMBOL(drm_dp_lttpr_max_link_rate); /** * drm_dp_lttpr_max_lane_count - get the maximum lane count supported by all LTTPRs * @caps: LTTPR common capabilities * * Returns the maximum lane count supported by all detected LTTPRs. */ int drm_dp_lttpr_max_lane_count(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]) { u8 max_lanes = dp_lttpr_common_cap(caps, DP_MAX_LANE_COUNT_PHY_REPEATER); return max_lanes & DP_MAX_LANE_COUNT_MASK; } EXPORT_SYMBOL(drm_dp_lttpr_max_lane_count); /** * drm_dp_lttpr_voltage_swing_level_3_supported - check for LTTPR vswing3 support * @caps: LTTPR PHY capabilities * * Returns true if the @caps for an LTTPR TX PHY indicate support for * voltage swing level 3. */ bool drm_dp_lttpr_voltage_swing_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]) { u8 txcap = dp_lttpr_phy_cap(caps, DP_TRANSMITTER_CAPABILITY_PHY_REPEATER1); return txcap & DP_VOLTAGE_SWING_LEVEL_3_SUPPORTED; } EXPORT_SYMBOL(drm_dp_lttpr_voltage_swing_level_3_supported); /** * drm_dp_lttpr_pre_emphasis_level_3_supported - check for LTTPR preemph3 support * @caps: LTTPR PHY capabilities * * Returns true if the @caps for an LTTPR TX PHY indicate support for * pre-emphasis level 3. */ bool drm_dp_lttpr_pre_emphasis_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]) { u8 txcap = dp_lttpr_phy_cap(caps, DP_TRANSMITTER_CAPABILITY_PHY_REPEATER1); return txcap & DP_PRE_EMPHASIS_LEVEL_3_SUPPORTED; } EXPORT_SYMBOL(drm_dp_lttpr_pre_emphasis_level_3_supported); /** * drm_dp_get_phy_test_pattern() - get the requested pattern from the sink. * @aux: DisplayPort AUX channel * @data: DP phy compliance test parameters. * * Returns 0 on success or a negative error code on failure. */ int drm_dp_get_phy_test_pattern(struct drm_dp_aux *aux, struct drm_dp_phy_test_params *data) { int err; u8 rate, lanes; err = drm_dp_dpcd_readb(aux, DP_TEST_LINK_RATE, &rate); if (err < 0) return err; data->link_rate = drm_dp_bw_code_to_link_rate(rate); err = drm_dp_dpcd_readb(aux, DP_TEST_LANE_COUNT, &lanes); if (err < 0) return err; data->num_lanes = lanes & DP_MAX_LANE_COUNT_MASK; if (lanes & DP_ENHANCED_FRAME_CAP) data->enhanced_frame_cap = true; err = drm_dp_dpcd_readb(aux, DP_PHY_TEST_PATTERN, &data->phy_pattern); if (err < 0) return err; switch (data->phy_pattern) { case DP_PHY_TEST_PATTERN_80BIT_CUSTOM: err = drm_dp_dpcd_read(aux, DP_TEST_80BIT_CUSTOM_PATTERN_7_0, &data->custom80, sizeof(data->custom80)); if (err < 0) return err; break; case DP_PHY_TEST_PATTERN_CP2520: err = drm_dp_dpcd_read(aux, DP_TEST_HBR2_SCRAMBLER_RESET, &data->hbr2_reset, sizeof(data->hbr2_reset)); if (err < 0) return err; } return 0; } EXPORT_SYMBOL(drm_dp_get_phy_test_pattern); /** * drm_dp_set_phy_test_pattern() - set the pattern to the sink. * @aux: DisplayPort AUX channel * @data: DP phy compliance test parameters. * @dp_rev: DP revision to use for compliance testing * * Returns 0 on success or a negative error code on failure. */ int drm_dp_set_phy_test_pattern(struct drm_dp_aux *aux, struct drm_dp_phy_test_params *data, u8 dp_rev) { int err, i; u8 link_config[2]; u8 test_pattern; link_config[0] = drm_dp_link_rate_to_bw_code(data->link_rate); link_config[1] = data->num_lanes; if (data->enhanced_frame_cap) link_config[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN; err = drm_dp_dpcd_write(aux, DP_LINK_BW_SET, link_config, 2); if (err < 0) return err; test_pattern = data->phy_pattern; if (dp_rev < 0x12) { test_pattern = (test_pattern << 2) & DP_LINK_QUAL_PATTERN_11_MASK; err = drm_dp_dpcd_writeb(aux, DP_TRAINING_PATTERN_SET, test_pattern); if (err < 0) return err; } else { for (i = 0; i < data->num_lanes; i++) { err = drm_dp_dpcd_writeb(aux, DP_LINK_QUAL_LANE0_SET + i, test_pattern); if (err < 0) return err; } } return 0; } EXPORT_SYMBOL(drm_dp_set_phy_test_pattern); static const char *dp_pixelformat_get_name(enum dp_pixelformat pixelformat) { if (pixelformat < 0 || pixelformat > DP_PIXELFORMAT_RESERVED) return "Invalid"; switch (pixelformat) { case DP_PIXELFORMAT_RGB: return "RGB"; case DP_PIXELFORMAT_YUV444: return "YUV444"; case DP_PIXELFORMAT_YUV422: return "YUV422"; case DP_PIXELFORMAT_YUV420: return "YUV420"; case DP_PIXELFORMAT_Y_ONLY: return "Y_ONLY"; case DP_PIXELFORMAT_RAW: return "RAW"; default: return "Reserved"; } } static const char *dp_colorimetry_get_name(enum dp_pixelformat pixelformat, enum dp_colorimetry colorimetry) { if (pixelformat < 0 || pixelformat > DP_PIXELFORMAT_RESERVED) return "Invalid"; switch (colorimetry) { case DP_COLORIMETRY_DEFAULT: switch (pixelformat) { case DP_PIXELFORMAT_RGB: return "sRGB"; case DP_PIXELFORMAT_YUV444: case DP_PIXELFORMAT_YUV422: case DP_PIXELFORMAT_YUV420: return "BT.601"; case DP_PIXELFORMAT_Y_ONLY: return "DICOM PS3.14"; case DP_PIXELFORMAT_RAW: return "Custom Color Profile"; default: return "Reserved"; } case DP_COLORIMETRY_RGB_WIDE_FIXED: /* and DP_COLORIMETRY_BT709_YCC */ switch (pixelformat) { case DP_PIXELFORMAT_RGB: return "Wide Fixed"; case DP_PIXELFORMAT_YUV444: case DP_PIXELFORMAT_YUV422: case DP_PIXELFORMAT_YUV420: return "BT.709"; default: return "Reserved"; } case DP_COLORIMETRY_RGB_WIDE_FLOAT: /* and DP_COLORIMETRY_XVYCC_601 */ switch (pixelformat) { case DP_PIXELFORMAT_RGB: return "Wide Float"; case DP_PIXELFORMAT_YUV444: case DP_PIXELFORMAT_YUV422: case DP_PIXELFORMAT_YUV420: return "xvYCC 601"; default: return "Reserved"; } case DP_COLORIMETRY_OPRGB: /* and DP_COLORIMETRY_XVYCC_709 */ switch (pixelformat) { case DP_PIXELFORMAT_RGB: return "OpRGB"; case DP_PIXELFORMAT_YUV444: case DP_PIXELFORMAT_YUV422: case DP_PIXELFORMAT_YUV420: return "xvYCC 709"; default: return "Reserved"; } case DP_COLORIMETRY_DCI_P3_RGB: /* and DP_COLORIMETRY_SYCC_601 */ switch (pixelformat) { case DP_PIXELFORMAT_RGB: return "DCI-P3"; case DP_PIXELFORMAT_YUV444: case DP_PIXELFORMAT_YUV422: case DP_PIXELFORMAT_YUV420: return "sYCC 601"; default: return "Reserved"; } case DP_COLORIMETRY_RGB_CUSTOM: /* and DP_COLORIMETRY_OPYCC_601 */ switch (pixelformat) { case DP_PIXELFORMAT_RGB: return "Custom Profile"; case DP_PIXELFORMAT_YUV444: case DP_PIXELFORMAT_YUV422: case DP_PIXELFORMAT_YUV420: return "OpYCC 601"; default: return "Reserved"; } case DP_COLORIMETRY_BT2020_RGB: /* and DP_COLORIMETRY_BT2020_CYCC */ switch (pixelformat) { case DP_PIXELFORMAT_RGB: return "BT.2020 RGB"; case DP_PIXELFORMAT_YUV444: case DP_PIXELFORMAT_YUV422: case DP_PIXELFORMAT_YUV420: return "BT.2020 CYCC"; default: return "Reserved"; } case DP_COLORIMETRY_BT2020_YCC: switch (pixelformat) { case DP_PIXELFORMAT_YUV444: case DP_PIXELFORMAT_YUV422: case DP_PIXELFORMAT_YUV420: return "BT.2020 YCC"; default: return "Reserved"; } default: return "Invalid"; } } static const char *dp_dynamic_range_get_name(enum dp_dynamic_range dynamic_range) { switch (dynamic_range) { case DP_DYNAMIC_RANGE_VESA: return "VESA range"; case DP_DYNAMIC_RANGE_CTA: return "CTA range"; default: return "Invalid"; } } static const char *dp_content_type_get_name(enum dp_content_type content_type) { switch (content_type) { case DP_CONTENT_TYPE_NOT_DEFINED: return "Not defined"; case DP_CONTENT_TYPE_GRAPHICS: return "Graphics"; case DP_CONTENT_TYPE_PHOTO: return "Photo"; case DP_CONTENT_TYPE_VIDEO: return "Video"; case DP_CONTENT_TYPE_GAME: return "Game"; default: return "Reserved"; } } void drm_dp_vsc_sdp_log(const char *level, struct device *dev, const struct drm_dp_vsc_sdp *vsc) { #define DP_SDP_LOG(fmt, ...) dev_printk(level, dev, fmt, ##__VA_ARGS__) DP_SDP_LOG("DP SDP: %s, revision %u, length %u\n", "VSC", vsc->revision, vsc->length); DP_SDP_LOG(" pixelformat: %s\n", dp_pixelformat_get_name(vsc->pixelformat)); DP_SDP_LOG(" colorimetry: %s\n", dp_colorimetry_get_name(vsc->pixelformat, vsc->colorimetry)); DP_SDP_LOG(" bpc: %u\n", vsc->bpc); DP_SDP_LOG(" dynamic range: %s\n", dp_dynamic_range_get_name(vsc->dynamic_range)); DP_SDP_LOG(" content type: %s\n", dp_content_type_get_name(vsc->content_type)); #undef DP_SDP_LOG } EXPORT_SYMBOL(drm_dp_vsc_sdp_log); /** * drm_dp_get_pcon_max_frl_bw() - maximum frl supported by PCON * @dpcd: DisplayPort configuration data * @port_cap: port capabilities * * Returns maximum frl bandwidth supported by PCON in GBPS, * returns 0 if not supported. */ int drm_dp_get_pcon_max_frl_bw(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4]) { int bw; u8 buf; buf = port_cap[2]; bw = buf & DP_PCON_MAX_FRL_BW; switch (bw) { case DP_PCON_MAX_9GBPS: return 9; case DP_PCON_MAX_18GBPS: return 18; case DP_PCON_MAX_24GBPS: return 24; case DP_PCON_MAX_32GBPS: return 32; case DP_PCON_MAX_40GBPS: return 40; case DP_PCON_MAX_48GBPS: return 48; case DP_PCON_MAX_0GBPS: default: return 0; } return 0; } EXPORT_SYMBOL(drm_dp_get_pcon_max_frl_bw); /** * drm_dp_pcon_frl_prepare() - Prepare PCON for FRL. * @aux: DisplayPort AUX channel * @enable_frl_ready_hpd: Configure DP_PCON_ENABLE_HPD_READY. * * Returns 0 if success, else returns negative error code. */ int drm_dp_pcon_frl_prepare(struct drm_dp_aux *aux, bool enable_frl_ready_hpd) { int ret; u8 buf = DP_PCON_ENABLE_SOURCE_CTL_MODE | DP_PCON_ENABLE_LINK_FRL_MODE; if (enable_frl_ready_hpd) buf |= DP_PCON_ENABLE_HPD_READY; ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_1, buf); return ret; } EXPORT_SYMBOL(drm_dp_pcon_frl_prepare); /** * drm_dp_pcon_is_frl_ready() - Is PCON ready for FRL * @aux: DisplayPort AUX channel * * Returns true if success, else returns false. */ bool drm_dp_pcon_is_frl_ready(struct drm_dp_aux *aux) { int ret; u8 buf; ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_TX_LINK_STATUS, &buf); if (ret < 0) return false; if (buf & DP_PCON_FRL_READY) return true; return false; } EXPORT_SYMBOL(drm_dp_pcon_is_frl_ready); /** * drm_dp_pcon_frl_configure_1() - Set HDMI LINK Configuration-Step1 * @aux: DisplayPort AUX channel * @max_frl_gbps: maximum frl bw to be configured between PCON and HDMI sink * @frl_mode: FRL Training mode, it can be either Concurrent or Sequential. * In Concurrent Mode, the FRL link bring up can be done along with * DP Link training. In Sequential mode, the FRL link bring up is done prior to * the DP Link training. * * Returns 0 if success, else returns negative error code. */ int drm_dp_pcon_frl_configure_1(struct drm_dp_aux *aux, int max_frl_gbps, u8 frl_mode) { int ret; u8 buf; ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_LINK_CONFIG_1, &buf); if (ret < 0) return ret; if (frl_mode == DP_PCON_ENABLE_CONCURRENT_LINK) buf |= DP_PCON_ENABLE_CONCURRENT_LINK; else buf &= ~DP_PCON_ENABLE_CONCURRENT_LINK; switch (max_frl_gbps) { case 9: buf |= DP_PCON_ENABLE_MAX_BW_9GBPS; break; case 18: buf |= DP_PCON_ENABLE_MAX_BW_18GBPS; break; case 24: buf |= DP_PCON_ENABLE_MAX_BW_24GBPS; break; case 32: buf |= DP_PCON_ENABLE_MAX_BW_32GBPS; break; case 40: buf |= DP_PCON_ENABLE_MAX_BW_40GBPS; break; case 48: buf |= DP_PCON_ENABLE_MAX_BW_48GBPS; break; case 0: buf |= DP_PCON_ENABLE_MAX_BW_0GBPS; break; default: return -EINVAL; } ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_1, buf); if (ret < 0) return ret; return 0; } EXPORT_SYMBOL(drm_dp_pcon_frl_configure_1); /** * drm_dp_pcon_frl_configure_2() - Set HDMI Link configuration Step-2 * @aux: DisplayPort AUX channel * @max_frl_mask : Max FRL BW to be tried by the PCON with HDMI Sink * @frl_type : FRL training type, can be Extended, or Normal. * In Normal FRL training, the PCON tries each frl bw from the max_frl_mask * starting from min, and stops when link training is successful. In Extended * FRL training, all frl bw selected in the mask are trained by the PCON. * * Returns 0 if success, else returns negative error code. */ int drm_dp_pcon_frl_configure_2(struct drm_dp_aux *aux, int max_frl_mask, u8 frl_type) { int ret; u8 buf = max_frl_mask; if (frl_type == DP_PCON_FRL_LINK_TRAIN_EXTENDED) buf |= DP_PCON_FRL_LINK_TRAIN_EXTENDED; else buf &= ~DP_PCON_FRL_LINK_TRAIN_EXTENDED; ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_2, buf); if (ret < 0) return ret; return 0; } EXPORT_SYMBOL(drm_dp_pcon_frl_configure_2); /** * drm_dp_pcon_reset_frl_config() - Re-Set HDMI Link configuration. * @aux: DisplayPort AUX channel * * Returns 0 if success, else returns negative error code. */ int drm_dp_pcon_reset_frl_config(struct drm_dp_aux *aux) { int ret; ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_1, 0x0); if (ret < 0) return ret; return 0; } EXPORT_SYMBOL(drm_dp_pcon_reset_frl_config); /** * drm_dp_pcon_frl_enable() - Enable HDMI link through FRL * @aux: DisplayPort AUX channel * * Returns 0 if success, else returns negative error code. */ int drm_dp_pcon_frl_enable(struct drm_dp_aux *aux) { int ret; u8 buf = 0; ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_LINK_CONFIG_1, &buf); if (ret < 0) return ret; if (!(buf & DP_PCON_ENABLE_SOURCE_CTL_MODE)) { drm_dbg_kms(aux->drm_dev, "%s: PCON in Autonomous mode, can't enable FRL\n", aux->name); return -EINVAL; } buf |= DP_PCON_ENABLE_HDMI_LINK; ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_1, buf); if (ret < 0) return ret; return 0; } EXPORT_SYMBOL(drm_dp_pcon_frl_enable); /** * drm_dp_pcon_hdmi_link_active() - check if the PCON HDMI LINK status is active. * @aux: DisplayPort AUX channel * * Returns true if link is active else returns false. */ bool drm_dp_pcon_hdmi_link_active(struct drm_dp_aux *aux) { u8 buf; int ret; ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_TX_LINK_STATUS, &buf); if (ret < 0) return false; return buf & DP_PCON_HDMI_TX_LINK_ACTIVE; } EXPORT_SYMBOL(drm_dp_pcon_hdmi_link_active); /** * drm_dp_pcon_hdmi_link_mode() - get the PCON HDMI LINK MODE * @aux: DisplayPort AUX channel * @frl_trained_mask: pointer to store bitmask of the trained bw configuration. * Valid only if the MODE returned is FRL. For Normal Link training mode * only 1 of the bits will be set, but in case of Extended mode, more than * one bits can be set. * * Returns the link mode : TMDS or FRL on success, else returns negative error * code. */ int drm_dp_pcon_hdmi_link_mode(struct drm_dp_aux *aux, u8 *frl_trained_mask) { u8 buf; int mode; int ret; ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_POST_FRL_STATUS, &buf); if (ret < 0) return ret; mode = buf & DP_PCON_HDMI_LINK_MODE; if (frl_trained_mask && DP_PCON_HDMI_MODE_FRL == mode) *frl_trained_mask = (buf & DP_PCON_HDMI_FRL_TRAINED_BW) >> 1; return mode; } EXPORT_SYMBOL(drm_dp_pcon_hdmi_link_mode); /** * drm_dp_pcon_hdmi_frl_link_error_count() - print the error count per lane * during link failure between PCON and HDMI sink * @aux: DisplayPort AUX channel * @connector: DRM connector * code. **/ void drm_dp_pcon_hdmi_frl_link_error_count(struct drm_dp_aux *aux, struct drm_connector *connector) { u8 buf, error_count; int i, num_error; struct drm_hdmi_info *hdmi = &connector->display_info.hdmi; for (i = 0; i < hdmi->max_lanes; i++) { if (drm_dp_dpcd_readb(aux, DP_PCON_HDMI_ERROR_STATUS_LN0 + i, &buf) < 0) return; error_count = buf & DP_PCON_HDMI_ERROR_COUNT_MASK; switch (error_count) { case DP_PCON_HDMI_ERROR_COUNT_HUNDRED_PLUS: num_error = 100; break; case DP_PCON_HDMI_ERROR_COUNT_TEN_PLUS: num_error = 10; break; case DP_PCON_HDMI_ERROR_COUNT_THREE_PLUS: num_error = 3; break; default: num_error = 0; } drm_err(aux->drm_dev, "%s: More than %d errors since the last read for lane %d", aux->name, num_error, i); } } EXPORT_SYMBOL(drm_dp_pcon_hdmi_frl_link_error_count); /* * drm_dp_pcon_enc_is_dsc_1_2 - Does PCON Encoder supports DSC 1.2 * @pcon_dsc_dpcd: DSC capabilities of the PCON DSC Encoder * * Returns true is PCON encoder is DSC 1.2 else returns false. */ bool drm_dp_pcon_enc_is_dsc_1_2(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]) { u8 buf; u8 major_v, minor_v; buf = pcon_dsc_dpcd[DP_PCON_DSC_VERSION - DP_PCON_DSC_ENCODER]; major_v = (buf & DP_PCON_DSC_MAJOR_MASK) >> DP_PCON_DSC_MAJOR_SHIFT; minor_v = (buf & DP_PCON_DSC_MINOR_MASK) >> DP_PCON_DSC_MINOR_SHIFT; if (major_v == 1 && minor_v == 2) return true; return false; } EXPORT_SYMBOL(drm_dp_pcon_enc_is_dsc_1_2); /* * drm_dp_pcon_dsc_max_slices - Get max slices supported by PCON DSC Encoder * @pcon_dsc_dpcd: DSC capabilities of the PCON DSC Encoder * * Returns maximum no. of slices supported by the PCON DSC Encoder. */ int drm_dp_pcon_dsc_max_slices(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]) { u8 slice_cap1, slice_cap2; slice_cap1 = pcon_dsc_dpcd[DP_PCON_DSC_SLICE_CAP_1 - DP_PCON_DSC_ENCODER]; slice_cap2 = pcon_dsc_dpcd[DP_PCON_DSC_SLICE_CAP_2 - DP_PCON_DSC_ENCODER]; if (slice_cap2 & DP_PCON_DSC_24_PER_DSC_ENC) return 24; if (slice_cap2 & DP_PCON_DSC_20_PER_DSC_ENC) return 20; if (slice_cap2 & DP_PCON_DSC_16_PER_DSC_ENC) return 16; if (slice_cap1 & DP_PCON_DSC_12_PER_DSC_ENC) return 12; if (slice_cap1 & DP_PCON_DSC_10_PER_DSC_ENC) return 10; if (slice_cap1 & DP_PCON_DSC_8_PER_DSC_ENC) return 8; if (slice_cap1 & DP_PCON_DSC_6_PER_DSC_ENC) return 6; if (slice_cap1 & DP_PCON_DSC_4_PER_DSC_ENC) return 4; if (slice_cap1 & DP_PCON_DSC_2_PER_DSC_ENC) return 2; if (slice_cap1 & DP_PCON_DSC_1_PER_DSC_ENC) return 1; return 0; } EXPORT_SYMBOL(drm_dp_pcon_dsc_max_slices); /* * drm_dp_pcon_dsc_max_slice_width() - Get max slice width for Pcon DSC encoder * @pcon_dsc_dpcd: DSC capabilities of the PCON DSC Encoder * * Returns maximum width of the slices in pixel width i.e. no. of pixels x 320. */ int drm_dp_pcon_dsc_max_slice_width(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]) { u8 buf; buf = pcon_dsc_dpcd[DP_PCON_DSC_MAX_SLICE_WIDTH - DP_PCON_DSC_ENCODER]; return buf * DP_DSC_SLICE_WIDTH_MULTIPLIER; } EXPORT_SYMBOL(drm_dp_pcon_dsc_max_slice_width); /* * drm_dp_pcon_dsc_bpp_incr() - Get bits per pixel increment for PCON DSC encoder * @pcon_dsc_dpcd: DSC capabilities of the PCON DSC Encoder * * Returns the bpp precision supported by the PCON encoder. */ int drm_dp_pcon_dsc_bpp_incr(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]) { u8 buf; buf = pcon_dsc_dpcd[DP_PCON_DSC_BPP_INCR - DP_PCON_DSC_ENCODER]; switch (buf & DP_PCON_DSC_BPP_INCR_MASK) { case DP_PCON_DSC_ONE_16TH_BPP: return 16; case DP_PCON_DSC_ONE_8TH_BPP: return 8; case DP_PCON_DSC_ONE_4TH_BPP: return 4; case DP_PCON_DSC_ONE_HALF_BPP: return 2; case DP_PCON_DSC_ONE_BPP: return 1; } return 0; } EXPORT_SYMBOL(drm_dp_pcon_dsc_bpp_incr); static int drm_dp_pcon_configure_dsc_enc(struct drm_dp_aux *aux, u8 pps_buf_config) { u8 buf; int ret; ret = drm_dp_dpcd_readb(aux, DP_PROTOCOL_CONVERTER_CONTROL_2, &buf); if (ret < 0) return ret; buf |= DP_PCON_ENABLE_DSC_ENCODER; if (pps_buf_config <= DP_PCON_ENC_PPS_OVERRIDE_EN_BUFFER) { buf &= ~DP_PCON_ENCODER_PPS_OVERRIDE_MASK; buf |= pps_buf_config << 2; } ret = drm_dp_dpcd_writeb(aux, DP_PROTOCOL_CONVERTER_CONTROL_2, buf); if (ret < 0) return ret; return 0; } /** * drm_dp_pcon_pps_default() - Let PCON fill the default pps parameters * for DSC1.2 between PCON & HDMI2.1 sink * @aux: DisplayPort AUX channel * * Returns 0 on success, else returns negative error code. */ int drm_dp_pcon_pps_default(struct drm_dp_aux *aux) { int ret; ret = drm_dp_pcon_configure_dsc_enc(aux, DP_PCON_ENC_PPS_OVERRIDE_DISABLED); if (ret < 0) return ret; return 0; } EXPORT_SYMBOL(drm_dp_pcon_pps_default); /** * drm_dp_pcon_pps_override_buf() - Configure PPS encoder override buffer for * HDMI sink * @aux: DisplayPort AUX channel * @pps_buf: 128 bytes to be written into PPS buffer for HDMI sink by PCON. * * Returns 0 on success, else returns negative error code. */ int drm_dp_pcon_pps_override_buf(struct drm_dp_aux *aux, u8 pps_buf[128]) { int ret; ret = drm_dp_dpcd_write(aux, DP_PCON_HDMI_PPS_OVERRIDE_BASE, &pps_buf, 128); if (ret < 0) return ret; ret = drm_dp_pcon_configure_dsc_enc(aux, DP_PCON_ENC_PPS_OVERRIDE_EN_BUFFER); if (ret < 0) return ret; return 0; } EXPORT_SYMBOL(drm_dp_pcon_pps_override_buf); /* * drm_dp_pcon_pps_override_param() - Write PPS parameters to DSC encoder * override registers * @aux: DisplayPort AUX channel * @pps_param: 3 Parameters (2 Bytes each) : Slice Width, Slice Height, * bits_per_pixel. * * Returns 0 on success, else returns negative error code. */ int drm_dp_pcon_pps_override_param(struct drm_dp_aux *aux, u8 pps_param[6]) { int ret; ret = drm_dp_dpcd_write(aux, DP_PCON_HDMI_PPS_OVRD_SLICE_HEIGHT, &pps_param[0], 2); if (ret < 0) return ret; ret = drm_dp_dpcd_write(aux, DP_PCON_HDMI_PPS_OVRD_SLICE_WIDTH, &pps_param[2], 2); if (ret < 0) return ret; ret = drm_dp_dpcd_write(aux, DP_PCON_HDMI_PPS_OVRD_BPP, &pps_param[4], 2); if (ret < 0) return ret; ret = drm_dp_pcon_configure_dsc_enc(aux, DP_PCON_ENC_PPS_OVERRIDE_EN_BUFFER); if (ret < 0) return ret; return 0; } EXPORT_SYMBOL(drm_dp_pcon_pps_override_param); /* * drm_dp_pcon_convert_rgb_to_ycbcr() - Configure the PCon to convert RGB to Ycbcr * @aux: displayPort AUX channel * @color_spc: Color-space/s for which conversion is to be enabled, 0 for disable. * * Returns 0 on success, else returns negative error code. */ int drm_dp_pcon_convert_rgb_to_ycbcr(struct drm_dp_aux *aux, u8 color_spc) { int ret; u8 buf; ret = drm_dp_dpcd_readb(aux, DP_PROTOCOL_CONVERTER_CONTROL_2, &buf); if (ret < 0) return ret; if (color_spc & DP_CONVERSION_RGB_YCBCR_MASK) buf |= (color_spc & DP_CONVERSION_RGB_YCBCR_MASK); else buf &= ~DP_CONVERSION_RGB_YCBCR_MASK; ret = drm_dp_dpcd_writeb(aux, DP_PROTOCOL_CONVERTER_CONTROL_2, buf); if (ret < 0) return ret; return 0; } EXPORT_SYMBOL(drm_dp_pcon_convert_rgb_to_ycbcr); /** * drm_edp_backlight_set_level() - Set the backlight level of an eDP panel via AUX * @aux: The DP AUX channel to use * @bl: Backlight capability info from drm_edp_backlight_init() * @level: The brightness level to set * * Sets the brightness level of an eDP panel's backlight. Note that the panel's backlight must * already have been enabled by the driver by calling drm_edp_backlight_enable(). * * Returns: %0 on success, negative error code on failure */ int drm_edp_backlight_set_level(struct drm_dp_aux *aux, const struct drm_edp_backlight_info *bl, u16 level) { int ret; u8 buf[2] = { 0 }; if (bl->lsb_reg_used) { buf[0] = (level & 0xff00) >> 8; buf[1] = (level & 0x00ff); } else { buf[0] = level; } ret = drm_dp_dpcd_write(aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB, buf, sizeof(buf)); if (ret != sizeof(buf)) { drm_err(aux->drm_dev, "%s: Failed to write aux backlight level: %d\n", aux->name, ret); return ret < 0 ? ret : -EIO; } return 0; } EXPORT_SYMBOL(drm_edp_backlight_set_level); static int drm_edp_backlight_set_enable(struct drm_dp_aux *aux, const struct drm_edp_backlight_info *bl, bool enable) { int ret; u8 buf; /* The panel uses something other then DPCD for enabling its backlight */ if (!bl->aux_enable) return 0; ret = drm_dp_dpcd_readb(aux, DP_EDP_DISPLAY_CONTROL_REGISTER, &buf); if (ret != 1) { drm_err(aux->drm_dev, "%s: Failed to read eDP display control register: %d\n", aux->name, ret); return ret < 0 ? ret : -EIO; } if (enable) buf |= DP_EDP_BACKLIGHT_ENABLE; else buf &= ~DP_EDP_BACKLIGHT_ENABLE; ret = drm_dp_dpcd_writeb(aux, DP_EDP_DISPLAY_CONTROL_REGISTER, buf); if (ret != 1) { drm_err(aux->drm_dev, "%s: Failed to write eDP display control register: %d\n", aux->name, ret); return ret < 0 ? ret : -EIO; } return 0; } /** * drm_edp_backlight_enable() - Enable an eDP panel's backlight using DPCD * @aux: The DP AUX channel to use * @bl: Backlight capability info from drm_edp_backlight_init() * @level: The initial backlight level to set via AUX, if there is one * * This function handles enabling DPCD backlight controls on a panel over DPCD, while additionally * restoring any important backlight state such as the given backlight level, the brightness byte * count, backlight frequency, etc. * * Note that certain panels, while supporting brightness level controls over DPCD, may not support * having their backlights enabled via the standard %DP_EDP_DISPLAY_CONTROL_REGISTER. On such panels * &drm_edp_backlight_info.aux_enable will be set to %false, this function will skip the step of * programming the %DP_EDP_DISPLAY_CONTROL_REGISTER, and the driver must perform the required * implementation specific step for enabling the backlight after calling this function. * * Returns: %0 on success, negative error code on failure. */ int drm_edp_backlight_enable(struct drm_dp_aux *aux, const struct drm_edp_backlight_info *bl, const u16 level) { int ret; u8 dpcd_buf, new_dpcd_buf; ret = drm_dp_dpcd_readb(aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf); if (ret != 1) { drm_dbg_kms(aux->drm_dev, "%s: Failed to read backlight mode: %d\n", aux->name, ret); return ret < 0 ? ret : -EIO; } new_dpcd_buf = dpcd_buf; if ((dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK) != DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD) { new_dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK; new_dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD; if (bl->pwmgen_bit_count) { ret = drm_dp_dpcd_writeb(aux, DP_EDP_PWMGEN_BIT_COUNT, bl->pwmgen_bit_count); if (ret != 1) drm_dbg_kms(aux->drm_dev, "%s: Failed to write aux pwmgen bit count: %d\n", aux->name, ret); } } if (bl->pwm_freq_pre_divider) { ret = drm_dp_dpcd_writeb(aux, DP_EDP_BACKLIGHT_FREQ_SET, bl->pwm_freq_pre_divider); if (ret != 1) drm_dbg_kms(aux->drm_dev, "%s: Failed to write aux backlight frequency: %d\n", aux->name, ret); else new_dpcd_buf |= DP_EDP_BACKLIGHT_FREQ_AUX_SET_ENABLE; } if (new_dpcd_buf != dpcd_buf) { ret = drm_dp_dpcd_writeb(aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER, new_dpcd_buf); if (ret != 1) { drm_dbg_kms(aux->drm_dev, "%s: Failed to write aux backlight mode: %d\n", aux->name, ret); return ret < 0 ? ret : -EIO; } } ret = drm_edp_backlight_set_level(aux, bl, level); if (ret < 0) return ret; ret = drm_edp_backlight_set_enable(aux, bl, true); if (ret < 0) return ret; return 0; } EXPORT_SYMBOL(drm_edp_backlight_enable); /** * drm_edp_backlight_disable() - Disable an eDP backlight using DPCD, if supported * @aux: The DP AUX channel to use * @bl: Backlight capability info from drm_edp_backlight_init() * * This function handles disabling DPCD backlight controls on a panel over AUX. Note that some * panels have backlights that are enabled/disabled by other means, despite having their brightness * values controlled through DPCD. On such panels &drm_edp_backlight_info.aux_enable will be set to * %false, this function will become a no-op (and we will skip updating * %DP_EDP_DISPLAY_CONTROL_REGISTER), and the driver must take care to perform it's own * implementation specific step for disabling the backlight. * * Returns: %0 on success or no-op, negative error code on failure. */ int drm_edp_backlight_disable(struct drm_dp_aux *aux, const struct drm_edp_backlight_info *bl) { int ret; ret = drm_edp_backlight_set_enable(aux, bl, false); if (ret < 0) return ret; return 0; } EXPORT_SYMBOL(drm_edp_backlight_disable); static inline int drm_edp_backlight_probe_max(struct drm_dp_aux *aux, struct drm_edp_backlight_info *bl, u16 driver_pwm_freq_hz, const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE]) { int fxp, fxp_min, fxp_max, fxp_actual, f = 1; int ret; u8 pn, pn_min, pn_max; ret = drm_dp_dpcd_readb(aux, DP_EDP_PWMGEN_BIT_COUNT, &pn); if (ret != 1) { drm_dbg_kms(aux->drm_dev, "%s: Failed to read pwmgen bit count cap: %d\n", aux->name, ret); return -ENODEV; } pn &= DP_EDP_PWMGEN_BIT_COUNT_MASK; bl->max = (1 << pn) - 1; if (!driver_pwm_freq_hz) return 0; /* * Set PWM Frequency divider to match desired frequency provided by the driver. * The PWM Frequency is calculated as 27Mhz / (F x P). * - Where F = PWM Frequency Pre-Divider value programmed by field 7:0 of the * EDP_BACKLIGHT_FREQ_SET register (DPCD Address 00728h) * - Where P = 2^Pn, where Pn is the value programmed by field 4:0 of the * EDP_PWMGEN_BIT_COUNT register (DPCD Address 00724h) */ /* Find desired value of (F x P) * Note that, if F x P is out of supported range, the maximum value or minimum value will * applied automatically. So no need to check that. */ fxp = DIV_ROUND_CLOSEST(1000 * DP_EDP_BACKLIGHT_FREQ_BASE_KHZ, driver_pwm_freq_hz); /* Use highest possible value of Pn for more granularity of brightness adjustment while * satisfying the conditions below. * - Pn is in the range of Pn_min and Pn_max * - F is in the range of 1 and 255 * - FxP is within 25% of desired value. * Note: 25% is arbitrary value and may need some tweak. */ ret = drm_dp_dpcd_readb(aux, DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN, &pn_min); if (ret != 1) { drm_dbg_kms(aux->drm_dev, "%s: Failed to read pwmgen bit count cap min: %d\n", aux->name, ret); return 0; } ret = drm_dp_dpcd_readb(aux, DP_EDP_PWMGEN_BIT_COUNT_CAP_MAX, &pn_max); if (ret != 1) { drm_dbg_kms(aux->drm_dev, "%s: Failed to read pwmgen bit count cap max: %d\n", aux->name, ret); return 0; } pn_min &= DP_EDP_PWMGEN_BIT_COUNT_MASK; pn_max &= DP_EDP_PWMGEN_BIT_COUNT_MASK; /* Ensure frequency is within 25% of desired value */ fxp_min = DIV_ROUND_CLOSEST(fxp * 3, 4); fxp_max = DIV_ROUND_CLOSEST(fxp * 5, 4); if (fxp_min < (1 << pn_min) || (255 << pn_max) < fxp_max) { drm_dbg_kms(aux->drm_dev, "%s: Driver defined backlight frequency (%d) out of range\n", aux->name, driver_pwm_freq_hz); return 0; } for (pn = pn_max; pn >= pn_min; pn--) { f = clamp(DIV_ROUND_CLOSEST(fxp, 1 << pn), 1, 255); fxp_actual = f << pn; if (fxp_min <= fxp_actual && fxp_actual <= fxp_max) break; } ret = drm_dp_dpcd_writeb(aux, DP_EDP_PWMGEN_BIT_COUNT, pn); if (ret != 1) { drm_dbg_kms(aux->drm_dev, "%s: Failed to write aux pwmgen bit count: %d\n", aux->name, ret); return 0; } bl->pwmgen_bit_count = pn; bl->max = (1 << pn) - 1; if (edp_dpcd[2] & DP_EDP_BACKLIGHT_FREQ_AUX_SET_CAP) { bl->pwm_freq_pre_divider = f; drm_dbg_kms(aux->drm_dev, "%s: Using backlight frequency from driver (%dHz)\n", aux->name, driver_pwm_freq_hz); } return 0; } static inline int drm_edp_backlight_probe_level(struct drm_dp_aux *aux, struct drm_edp_backlight_info *bl, u8 *current_mode) { int ret; u8 buf[2]; u8 mode_reg; ret = drm_dp_dpcd_readb(aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &mode_reg); if (ret != 1) { drm_dbg_kms(aux->drm_dev, "%s: Failed to read backlight mode: %d\n", aux->name, ret); return ret < 0 ? ret : -EIO; } *current_mode = (mode_reg & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK); if (*current_mode == DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD) { int size = 1 + bl->lsb_reg_used; ret = drm_dp_dpcd_read(aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB, buf, size); if (ret != size) { drm_dbg_kms(aux->drm_dev, "%s: Failed to read backlight level: %d\n", aux->name, ret); return ret < 0 ? ret : -EIO; } if (bl->lsb_reg_used) return (buf[0] << 8) | buf[1]; else return buf[0]; } /* * If we're not in DPCD control mode yet, the programmed brightness value is meaningless and * the driver should assume max brightness */ return bl->max; } /** * drm_edp_backlight_init() - Probe a display panel's TCON using the standard VESA eDP backlight * interface. * @aux: The DP aux device to use for probing * @bl: The &drm_edp_backlight_info struct to fill out with information on the backlight * @driver_pwm_freq_hz: Optional PWM frequency from the driver in hz * @edp_dpcd: A cached copy of the eDP DPCD * @current_level: Where to store the probed brightness level * @current_mode: Where to store the currently set backlight control mode * * Initializes a &drm_edp_backlight_info struct by probing @aux for it's backlight capabilities, * along with also probing the current and maximum supported brightness levels. * * If @driver_pwm_freq_hz is non-zero, this will be used as the backlight frequency. Otherwise, the * default frequency from the panel is used. * * Returns: %0 on success, negative error code on failure. */ int drm_edp_backlight_init(struct drm_dp_aux *aux, struct drm_edp_backlight_info *bl, u16 driver_pwm_freq_hz, const u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE], u16 *current_level, u8 *current_mode) { int ret; if (edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) bl->aux_enable = true; if (edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT) bl->lsb_reg_used = true; ret = drm_edp_backlight_probe_max(aux, bl, driver_pwm_freq_hz, edp_dpcd); if (ret < 0) return ret; ret = drm_edp_backlight_probe_level(aux, bl, current_mode); if (ret < 0) return ret; *current_level = ret; drm_dbg_kms(aux->drm_dev, "%s: Found backlight level=%d/%d pwm_freq_pre_divider=%d mode=%x\n", aux->name, *current_level, bl->max, bl->pwm_freq_pre_divider, *current_mode); drm_dbg_kms(aux->drm_dev, "%s: Backlight caps: pwmgen_bit_count=%d lsb_reg_used=%d aux_enable=%d\n", aux->name, bl->pwmgen_bit_count, bl->lsb_reg_used, bl->aux_enable); return 0; } EXPORT_SYMBOL(drm_edp_backlight_init); #if IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \ (IS_MODULE(CONFIG_DRM_KMS_HELPER) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE)) static int dp_aux_backlight_update_status(struct backlight_device *bd) { struct dp_aux_backlight *bl = bl_get_data(bd); u16 brightness = backlight_get_brightness(bd); int ret = 0; if (!backlight_is_blank(bd)) { if (!bl->enabled) { drm_edp_backlight_enable(bl->aux, &bl->info, brightness); bl->enabled = true; return 0; } ret = drm_edp_backlight_set_level(bl->aux, &bl->info, brightness); } else { if (bl->enabled) { drm_edp_backlight_disable(bl->aux, &bl->info); bl->enabled = false; } } return ret; } static const struct backlight_ops dp_aux_bl_ops = { .update_status = dp_aux_backlight_update_status, }; /** * drm_panel_dp_aux_backlight - create and use DP AUX backlight * @panel: DRM panel * @aux: The DP AUX channel to use * * Use this function to create and handle backlight if your panel * supports backlight control over DP AUX channel using DPCD * registers as per VESA's standard backlight control interface. * * When the panel is enabled backlight will be enabled after a * successful call to &drm_panel_funcs.enable() * * When the panel is disabled backlight will be disabled before the * call to &drm_panel_funcs.disable(). * * A typical implementation for a panel driver supporting backlight * control over DP AUX will call this function at probe time. * Backlight will then be handled transparently without requiring * any intervention from the driver. * * drm_panel_dp_aux_backlight() must be called after the call to drm_panel_init(). * * Return: 0 on success or a negative error code on failure. */ int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux) { struct dp_aux_backlight *bl; struct backlight_properties props = { 0 }; u16 current_level; u8 current_mode; u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE]; int ret; if (!panel || !panel->dev || !aux) return -EINVAL; ret = drm_dp_dpcd_read(aux, DP_EDP_DPCD_REV, edp_dpcd, EDP_DISPLAY_CTL_CAP_SIZE); if (ret < 0) return ret; if (!drm_edp_backlight_supported(edp_dpcd)) { DRM_DEV_INFO(panel->dev, "DP AUX backlight is not supported\n"); return 0; } bl = devm_kzalloc(panel->dev, sizeof(*bl), GFP_KERNEL); if (!bl) return -ENOMEM; bl->aux = aux; ret = drm_edp_backlight_init(aux, &bl->info, 0, edp_dpcd, ¤t_level, ¤t_mode); if (ret < 0) return ret; props.type = BACKLIGHT_RAW; props.brightness = current_level; props.max_brightness = bl->info.max; bl->base = devm_backlight_device_register(panel->dev, "dp_aux_backlight", panel->dev, bl, &dp_aux_bl_ops, &props); if (IS_ERR(bl->base)) return PTR_ERR(bl->base); backlight_disable(bl->base); panel->backlight = bl->base; return 0; } EXPORT_SYMBOL(drm_panel_dp_aux_backlight); #endif