diff options
Diffstat (limited to 'drivers/platform/chrome')
| -rw-r--r-- | drivers/platform/chrome/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/platform/chrome/Makefile | 1 | ||||
| -rw-r--r-- | drivers/platform/chrome/cros_ec_proto.c | 115 |
3 files changed, 123 insertions, 2 deletions
diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig index 2a6531a5fde8..cb1329919527 100644 --- a/drivers/platform/chrome/Kconfig +++ b/drivers/platform/chrome/Kconfig @@ -40,7 +40,7 @@ config CHROMEOS_PSTORE config CROS_EC_CHARDEV tristate "Chrome OS Embedded Controller userspace device interface" - depends on MFD_CROS_EC + depends on CROS_EC_PROTO ---help--- This driver adds support to talk with the ChromeOS EC from userspace. @@ -49,7 +49,7 @@ config CROS_EC_CHARDEV config CROS_EC_LPC tristate "ChromeOS Embedded Controller (LPC)" - depends on MFD_CROS_EC && (X86 || COMPILE_TEST) + depends on MFD_CROS_EC && CROS_EC_PROTO && (X86 || COMPILE_TEST) help If you say Y here, you get support for talking to the ChromeOS EC over an LPC bus. This uses a simple byte-level protocol with a @@ -59,4 +59,9 @@ config CROS_EC_LPC To compile this driver as a module, choose M here: the module will be called cros_ec_lpc. +config CROS_EC_PROTO + bool + help + ChromeOS EC communication protocol helpers. + endif # CHROMEOS_PLATFORMS diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile index bd8d8601e875..4a11b010f5d8 100644 --- a/drivers/platform/chrome/Makefile +++ b/drivers/platform/chrome/Makefile @@ -4,3 +4,4 @@ obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o cros_ec_devs-objs := cros_ec_dev.o cros_ec_sysfs.o cros_ec_lightbar.o obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_devs.o obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpc.o +obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c new file mode 100644 index 000000000000..58e98a24fd08 --- /dev/null +++ b/drivers/platform/chrome/cros_ec_proto.c @@ -0,0 +1,115 @@ +/* + * ChromeOS EC communication protocol helper functions + * + * Copyright (C) 2015 Google, Inc + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/mfd/cros_ec.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/module.h> +#include <linux/slab.h> + +#define EC_COMMAND_RETRIES 50 + +int cros_ec_prepare_tx(struct cros_ec_device *ec_dev, + struct cros_ec_command *msg) +{ + uint8_t *out; + int csum, i; + + BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE); + out = ec_dev->dout; + out[0] = EC_CMD_VERSION0 + msg->version; + out[1] = msg->command; + out[2] = msg->outsize; + csum = out[0] + out[1] + out[2]; + for (i = 0; i < msg->outsize; i++) + csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i]; + out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = (uint8_t)(csum & 0xff); + + return EC_MSG_TX_PROTO_BYTES + msg->outsize; +} +EXPORT_SYMBOL(cros_ec_prepare_tx); + +int cros_ec_check_result(struct cros_ec_device *ec_dev, + struct cros_ec_command *msg) +{ + switch (msg->result) { + case EC_RES_SUCCESS: + return 0; + case EC_RES_IN_PROGRESS: + dev_dbg(ec_dev->dev, "command 0x%02x in progress\n", + msg->command); + return -EAGAIN; + default: + dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n", + msg->command, msg->result); + return 0; + } +} +EXPORT_SYMBOL(cros_ec_check_result); + +int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev, + struct cros_ec_command *msg) +{ + int ret; + + mutex_lock(&ec_dev->lock); + ret = ec_dev->cmd_xfer(ec_dev, msg); + if (msg->result == EC_RES_IN_PROGRESS) { + int i; + struct cros_ec_command *status_msg; + struct ec_response_get_comms_status *status; + + status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status), + GFP_KERNEL); + if (!status_msg) { + ret = -ENOMEM; + goto exit; + } + + status_msg->version = 0; + status_msg->command = EC_CMD_GET_COMMS_STATUS; + status_msg->insize = sizeof(*status); + status_msg->outsize = 0; + + /* + * Query the EC's status until it's no longer busy or + * we encounter an error. + */ + for (i = 0; i < EC_COMMAND_RETRIES; i++) { + usleep_range(10000, 11000); + + ret = ec_dev->cmd_xfer(ec_dev, status_msg); + if (ret < 0) + break; + + msg->result = status_msg->result; + if (status_msg->result != EC_RES_SUCCESS) + break; + + status = (struct ec_response_get_comms_status *) + status_msg->data; + if (!(status->flags & EC_COMMS_STATUS_PROCESSING)) + break; + } + + kfree(status_msg); + } +exit: + mutex_unlock(&ec_dev->lock); + + return ret; +} +EXPORT_SYMBOL(cros_ec_cmd_xfer); |