summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
blob: 020422da2ae28de9c33ddce41fd3ca8eef3ed31f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
/*
 * Copyright © 2015 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */

#include "intel_display_types.h"
#include "intel_dp_aux_backlight.h"

static void set_aux_backlight_enable(struct intel_dp *intel_dp, bool enable)
{
	u8 reg_val = 0;

	/* Early return when display use other mechanism to enable backlight. */
	if (!(intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP))
		return;

	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER,
			      &reg_val) < 0) {
		DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
			      DP_EDP_DISPLAY_CONTROL_REGISTER);
		return;
	}
	if (enable)
		reg_val |= DP_EDP_BACKLIGHT_ENABLE;
	else
		reg_val &= ~(DP_EDP_BACKLIGHT_ENABLE);

	if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER,
			       reg_val) != 1) {
		DRM_DEBUG_KMS("Failed to %s aux backlight\n",
			      enable ? "enable" : "disable");
	}
}

/*
 * Read the current backlight value from DPCD register(s) based
 * on if 8-bit(MSB) or 16-bit(MSB and LSB) values are supported
 */
static u32 intel_dp_aux_get_backlight(struct intel_connector *connector)
{
	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	u8 read_val[2] = { 0x0 };
	u16 level = 0;

	if (drm_dp_dpcd_read(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
			     &read_val, sizeof(read_val)) < 0) {
		DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
			      DP_EDP_BACKLIGHT_BRIGHTNESS_MSB);
		return 0;
	}
	level = read_val[0];
	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
		level = (read_val[0] << 8 | read_val[1]);

	return level;
}

/*
 * Sends the current backlight level over the aux channel, checking if its using
 * 8-bit or 16 bit value (MSB and LSB)
 */
static void
intel_dp_aux_set_backlight(const struct drm_connector_state *conn_state, u32 level)
{
	struct intel_connector *connector = to_intel_connector(conn_state->connector);
	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	u8 vals[2] = { 0x0 };

	vals[0] = level;

	/* Write the MSB and/or LSB */
	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT) {
		vals[0] = (level & 0xFF00) >> 8;
		vals[1] = (level & 0xFF);
	}
	if (drm_dp_dpcd_write(&intel_dp->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB,
			      vals, sizeof(vals)) < 0) {
		DRM_DEBUG_KMS("Failed to write aux backlight level\n");
		return;
	}
}

/*
 * Set PWM Frequency divider to match desired frequency in vbt.
 * 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)
 */
static bool intel_dp_aux_set_pwm_freq(struct intel_connector *connector)
{
	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	int freq, fxp, fxp_min, fxp_max, fxp_actual, f = 1;
	u8 pn, pn_min, pn_max;

	/* 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.
	 */
	freq = dev_priv->vbt.backlight.pwm_freq_hz;
	DRM_DEBUG_KMS("VBT defined backlight frequency %u Hz\n", freq);
	if (!freq) {
		DRM_DEBUG_KMS("Use panel default backlight frequency\n");
		return false;
	}

	fxp = DIV_ROUND_CLOSEST(KHz(DP_EDP_BACKLIGHT_FREQ_BASE_KHZ), freq);

	/* Use highest possible value of Pn for more granularity of brightness
	 * adjustment while satifying 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.
	 */
	if (drm_dp_dpcd_readb(&intel_dp->aux,
			       DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN, &pn_min) != 1) {
		DRM_DEBUG_KMS("Failed to read pwmgen bit count cap min\n");
		return false;
	}
	if (drm_dp_dpcd_readb(&intel_dp->aux,
			       DP_EDP_PWMGEN_BIT_COUNT_CAP_MAX, &pn_max) != 1) {
		DRM_DEBUG_KMS("Failed to read pwmgen bit count cap max\n");
		return false;
	}
	pn_min &= DP_EDP_PWMGEN_BIT_COUNT_MASK;
	pn_max &= DP_EDP_PWMGEN_BIT_COUNT_MASK;

	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_DEBUG_KMS("VBT defined backlight frequency out of range\n");
		return false;
	}

	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;
	}

	if (drm_dp_dpcd_writeb(&intel_dp->aux,
			       DP_EDP_PWMGEN_BIT_COUNT, pn) < 0) {
		DRM_DEBUG_KMS("Failed to write aux pwmgen bit count\n");
		return false;
	}
	if (drm_dp_dpcd_writeb(&intel_dp->aux,
			       DP_EDP_BACKLIGHT_FREQ_SET, (u8) f) < 0) {
		DRM_DEBUG_KMS("Failed to write aux backlight freq\n");
		return false;
	}
	return true;
}

static void intel_dp_aux_enable_backlight(const struct intel_crtc_state *crtc_state,
					  const struct drm_connector_state *conn_state)
{
	struct intel_connector *connector = to_intel_connector(conn_state->connector);
	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	u8 dpcd_buf, new_dpcd_buf, edp_backlight_mode;

	if (drm_dp_dpcd_readb(&intel_dp->aux,
			DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) != 1) {
		DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
			      DP_EDP_BACKLIGHT_MODE_SET_REGISTER);
		return;
	}

	new_dpcd_buf = dpcd_buf;
	edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;

	switch (edp_backlight_mode) {
	case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM:
	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET:
	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT:
		new_dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
		new_dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
		break;

	/* Do nothing when it is already DPCD mode */
	case DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD:
	default:
		break;
	}

	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_FREQ_AUX_SET_CAP)
		if (intel_dp_aux_set_pwm_freq(connector))
			new_dpcd_buf |= DP_EDP_BACKLIGHT_FREQ_AUX_SET_ENABLE;

	if (new_dpcd_buf != dpcd_buf) {
		if (drm_dp_dpcd_writeb(&intel_dp->aux,
			DP_EDP_BACKLIGHT_MODE_SET_REGISTER, new_dpcd_buf) < 0) {
			DRM_DEBUG_KMS("Failed to write aux backlight mode\n");
		}
	}

	set_aux_backlight_enable(intel_dp, true);
	intel_dp_aux_set_backlight(conn_state, connector->panel.backlight.level);
}

static void intel_dp_aux_disable_backlight(const struct drm_connector_state *old_conn_state)
{
	set_aux_backlight_enable(enc_to_intel_dp(old_conn_state->best_encoder), false);
}

static int intel_dp_aux_setup_backlight(struct intel_connector *connector,
					enum pipe pipe)
{
	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
	struct intel_panel *panel = &connector->panel;

	if (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_BYTE_COUNT)
		panel->backlight.max = 0xFFFF;
	else
		panel->backlight.max = 0xFF;

	panel->backlight.min = 0;
	panel->backlight.level = intel_dp_aux_get_backlight(connector);

	panel->backlight.enabled = panel->backlight.level != 0;

	return 0;
}

static bool
intel_dp_aux_display_control_capable(struct intel_connector *connector)
{
	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);

	/* Check the eDP Display control capabilities registers to determine if
	 * the panel can support backlight control over the aux channel
	 */
	if (intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
	    (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP) &&
	    !(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP)) {
		DRM_DEBUG_KMS("AUX Backlight Control Supported!\n");
		return true;
	}
	return false;
}

int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector)
{
	struct intel_panel *panel = &intel_connector->panel;
	struct drm_i915_private *dev_priv = to_i915(intel_connector->base.dev);

	if (i915_modparams.enable_dpcd_backlight == 0 ||
	    (i915_modparams.enable_dpcd_backlight == -1 &&
	    dev_priv->vbt.backlight.type != INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE))
		return -ENODEV;

	if (!intel_dp_aux_display_control_capable(intel_connector))
		return -ENODEV;

	panel->backlight.setup = intel_dp_aux_setup_backlight;
	panel->backlight.enable = intel_dp_aux_enable_backlight;
	panel->backlight.disable = intel_dp_aux_disable_backlight;
	panel->backlight.set = intel_dp_aux_set_backlight;
	panel->backlight.get = intel_dp_aux_get_backlight;

	return 0;
}