diff options
Diffstat (limited to 'drivers/mfd/cros_ec_i2c.c')
| -rw-r--r-- | drivers/mfd/cros_ec_i2c.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/drivers/mfd/cros_ec_i2c.c b/drivers/mfd/cros_ec_i2c.c new file mode 100644 index 00000000000..123044608b6 --- /dev/null +++ b/drivers/mfd/cros_ec_i2c.c @@ -0,0 +1,201 @@ +/* + * ChromeOS EC multi-function device (I2C) + * + * 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. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/mfd/cros_ec.h> +#include <linux/mfd/cros_ec_commands.h> +#include <linux/platform_device.h> +#include <linux/slab.h> + +static inline struct cros_ec_device *to_ec_dev(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + + return i2c_get_clientdata(client); +} + +static int cros_ec_command_xfer(struct cros_ec_device *ec_dev, + struct cros_ec_msg *msg) +{ + struct i2c_client *client = ec_dev->priv; + int ret = -ENOMEM; + int i; + int packet_len; + u8 *out_buf = NULL; + u8 *in_buf = NULL; + u8 sum; + struct i2c_msg i2c_msg[2]; + + i2c_msg[0].addr = client->addr; + i2c_msg[0].flags = 0; + i2c_msg[1].addr = client->addr; + i2c_msg[1].flags = I2C_M_RD; + + /* + * allocate larger packet (one byte for checksum, one byte for + * length, and one for result code) + */ + packet_len = msg->in_len + 3; + in_buf = kzalloc(packet_len, GFP_KERNEL); + if (!in_buf) + goto done; + i2c_msg[1].len = packet_len; + i2c_msg[1].buf = (char *)in_buf; + + /* + * allocate larger packet (one byte for checksum, one for + * command code, one for length, and one for command version) + */ + packet_len = msg->out_len + 4; + out_buf = kzalloc(packet_len, GFP_KERNEL); + if (!out_buf) + goto done; + i2c_msg[0].len = packet_len; + i2c_msg[0].buf = (char *)out_buf; + + out_buf[0] = EC_CMD_VERSION0 + msg->version; + out_buf[1] = msg->cmd; + out_buf[2] = msg->out_len; + + /* copy message payload and compute checksum */ + sum = out_buf[0] + out_buf[1] + out_buf[2]; + for (i = 0; i < msg->out_len; i++) { + out_buf[3 + i] = msg->out_buf[i]; + sum += out_buf[3 + i]; + } + out_buf[3 + msg->out_len] = sum; + + /* send command to EC and read answer */ + ret = i2c_transfer(client->adapter, i2c_msg, 2); + if (ret < 0) { + dev_err(ec_dev->dev, "i2c transfer failed: %d\n", ret); + goto done; + } else if (ret != 2) { + dev_err(ec_dev->dev, "failed to get response: %d\n", ret); + ret = -EIO; + goto done; + } + + /* check response error code */ + if (i2c_msg[1].buf[0]) { + dev_warn(ec_dev->dev, "command 0x%02x returned an error %d\n", + msg->cmd, i2c_msg[1].buf[0]); + ret = -EINVAL; + goto done; + } + + /* copy response packet payload and compute checksum */ + sum = in_buf[0] + in_buf[1]; + for (i = 0; i < msg->in_len; i++) { + msg->in_buf[i] = in_buf[2 + i]; + sum += in_buf[2 + i]; + } + dev_dbg(ec_dev->dev, "packet: %*ph, sum = %02x\n", + i2c_msg[1].len, in_buf, sum); + if (sum != in_buf[2 + msg->in_len]) { + dev_err(ec_dev->dev, "bad packet checksum\n"); + ret = -EBADMSG; + goto done; + } + + ret = 0; + done: + kfree(in_buf); + kfree(out_buf); + return ret; +} + +static int cros_ec_probe_i2c(struct i2c_client *client, + const struct i2c_device_id *dev_id) +{ + struct device *dev = &client->dev; + struct cros_ec_device *ec_dev = NULL; + int err; + + ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); + if (!ec_dev) + return -ENOMEM; + + i2c_set_clientdata(client, ec_dev); + ec_dev->name = "I2C"; + ec_dev->dev = dev; + ec_dev->priv = client; + ec_dev->irq = client->irq; + ec_dev->command_xfer = cros_ec_command_xfer; + ec_dev->ec_name = client->name; + ec_dev->phys_name = client->adapter->name; + ec_dev->parent = &client->dev; + + err = cros_ec_register(ec_dev); + if (err) { + dev_err(dev, "cannot register EC\n"); + return err; + } + + return 0; +} + +static int cros_ec_remove_i2c(struct i2c_client *client) +{ + struct cros_ec_device *ec_dev = i2c_get_clientdata(client); + + cros_ec_remove(ec_dev); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int cros_ec_i2c_suspend(struct device *dev) +{ + struct cros_ec_device *ec_dev = to_ec_dev(dev); + + return cros_ec_suspend(ec_dev); +} + +static int cros_ec_i2c_resume(struct device *dev) +{ + struct cros_ec_device *ec_dev = to_ec_dev(dev); + + return cros_ec_resume(ec_dev); +} +#endif + +static SIMPLE_DEV_PM_OPS(cros_ec_i2c_pm_ops, cros_ec_i2c_suspend, + cros_ec_i2c_resume); + +static const struct i2c_device_id cros_ec_i2c_id[] = { + { "cros-ec-i2c", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, cros_ec_i2c_id); + +static struct i2c_driver cros_ec_driver = { + .driver = { + .name = "cros-ec-i2c", + .owner = THIS_MODULE, + .pm = &cros_ec_i2c_pm_ops, + }, + .probe = cros_ec_probe_i2c, + .remove = cros_ec_remove_i2c, + .id_table = cros_ec_i2c_id, +}; + +module_i2c_driver(cros_ec_driver); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("ChromeOS EC multi function device"); |