diff options
Diffstat (limited to 'kernel/drivers/mfd/cros_ec.c')
| -rw-r--r-- | kernel/drivers/mfd/cros_ec.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/kernel/drivers/mfd/cros_ec.c b/kernel/drivers/mfd/cros_ec.c new file mode 100644 index 000000000..c4aecc6f8 --- /dev/null +++ b/kernel/drivers/mfd/cros_ec.c @@ -0,0 +1,198 @@ +/* + * ChromeOS EC multi-function device + * + * Copyright (C) 2012 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. + * + * The ChromeOS EC multi function device is used to mux all the requests + * to the EC device for its multiple features: keyboard controller, + * battery charging and regulator control, firmware update. + */ + +#include <linux/interrupt.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/mfd/core.h> +#include <linux/mfd/cros_ec.h> +#include <linux/mfd/cros_ec_commands.h> +#include <linux/delay.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->outdata[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.command = EC_CMD_GET_COMMS_STATUS; + status_msg.insize = sizeof(*status); + + /* + * 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.indata; + if (!(status->flags & EC_COMMS_STATUS_PROCESSING)) + break; + } + } + mutex_unlock(&ec_dev->lock); + + return ret; +} +EXPORT_SYMBOL(cros_ec_cmd_xfer); + +static const struct mfd_cell cros_devs[] = { + { + .name = "cros-ec-keyb", + .id = 1, + .of_compatible = "google,cros-ec-keyb", + }, + { + .name = "cros-ec-i2c-tunnel", + .id = 2, + .of_compatible = "google,cros-ec-i2c-tunnel", + }, + { + .name = "cros-ec-ctl", + .id = 3, + }, +}; + +int cros_ec_register(struct cros_ec_device *ec_dev) +{ + struct device *dev = ec_dev->dev; + int err = 0; + + if (ec_dev->din_size) { + ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL); + if (!ec_dev->din) + return -ENOMEM; + } + if (ec_dev->dout_size) { + ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL); + if (!ec_dev->dout) + return -ENOMEM; + } + + mutex_init(&ec_dev->lock); + + err = mfd_add_devices(dev, 0, cros_devs, + ARRAY_SIZE(cros_devs), + NULL, ec_dev->irq, NULL); + if (err) { + dev_err(dev, "failed to add mfd devices\n"); + return err; + } + + dev_info(dev, "Chrome EC device registered\n"); + + return 0; +} +EXPORT_SYMBOL(cros_ec_register); + +int cros_ec_remove(struct cros_ec_device *ec_dev) +{ + mfd_remove_devices(ec_dev->dev); + + return 0; +} +EXPORT_SYMBOL(cros_ec_remove); + +#ifdef CONFIG_PM_SLEEP +int cros_ec_suspend(struct cros_ec_device *ec_dev) +{ + struct device *dev = ec_dev->dev; + + if (device_may_wakeup(dev)) + ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq); + + disable_irq(ec_dev->irq); + ec_dev->was_wake_device = ec_dev->wake_enabled; + + return 0; +} +EXPORT_SYMBOL(cros_ec_suspend); + +int cros_ec_resume(struct cros_ec_device *ec_dev) +{ + enable_irq(ec_dev->irq); + + if (ec_dev->wake_enabled) { + disable_irq_wake(ec_dev->irq); + ec_dev->wake_enabled = 0; + } + + return 0; +} +EXPORT_SYMBOL(cros_ec_resume); + +#endif + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("ChromeOS EC core driver"); |