mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-11 12:28:41 +08:00
mfd: Add ChromeOS EC I2C driver
This uses an I2C bus to talk to the ChromeOS EC. The protocol is defined by the EC and is fairly simple, with a length byte, checksum, command byte and version byte (to permit easy creation of new commands). Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Che-Liang Chiou <clchiou@chromium.org> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This commit is contained in:
Simon Glass
Samuel Ortiz
parent
4ab6174e8c
commit
8996900948
@ -29,6 +29,16 @@ config MFD_CROS_EC
|
||||
You also ned to enable the driver for the bus you are using. The
|
||||
protocol for talking to the EC is defined by the bus driver.
|
||||
|
||||
config MFD_CROS_EC_I2C
|
||||
tristate "ChromeOS Embedded Controller (I2C)"
|
||||
depends on MFD_CROS_EC && I2C
|
||||
|
||||
help
|
||||
If you say Y here, you get support for talking to the ChromeOS
|
||||
EC through an I2C bus. This uses a simple byte-level protocol with
|
||||
a checksum. Failing accesses will be retried three times to
|
||||
improve reliability.
|
||||
|
||||
config MFD_88PM800
|
||||
tristate "Support Marvell 88PM800"
|
||||
depends on I2C=y && GENERIC_HARDIRQS
|
||||
|
||||
@ -9,6 +9,7 @@ obj-$(CONFIG_MFD_88PM805) += 88pm805.o 88pm80x.o
|
||||
obj-$(CONFIG_MFD_SM501) += sm501.o
|
||||
obj-$(CONFIG_MFD_ASIC3) += asic3.o tmio_core.o
|
||||
obj-$(CONFIG_MFD_CROS_EC) += cros_ec.o
|
||||
obj-$(CONFIG_MFD_CROS_EC_I2C) += cros_ec_i2c.o
|
||||
|
||||
rtsx_pci-objs := rtsx_pcr.o rts5209.o rts5229.o rtl8411.o rts5227.o
|
||||
obj-$(CONFIG_MFD_RTSX_PCI) += rtsx_pci.o
|
||||
|
||||
201
drivers/mfd/cros_ec_i2c.c
Normal file
201
drivers/mfd/cros_ec_i2c.c
Normal file
@ -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");
|
||||
Loading…
Reference in New Issue
Block a user