/*
* 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/delay.h>
#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>
/**
* Request format for protocol v3
* byte 0 0xda (EC_COMMAND_PROTOCOL_3)
* byte 1-8 struct ec_host_request
* byte 10- response data
*/
struct ec_host_request_i2c {
/* Always 0xda to backward compatible with v2 struct */
uint8_t command_protocol;
struct ec_host_request ec_request;
} __packed;
/*
* Response format for protocol v3
* byte 0 result code
* byte 1 packet_length
* byte 2-9 struct ec_host_response
* byte 10- response data
*/
struct ec_host_response_i2c {
uint8_t result;
uint8_t packet_length;
struct ec_host_response ec_response;
} __packed;
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_pkt_xfer_i2c(struct cros_ec_device *ec_dev,
struct cros_ec_command *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];
struct ec_host_response *ec_response;
struct ec_host_request_i2c *ec_request_i2c;
struct ec_host_response_i2c *ec_response_i2c;
int request_header_size = sizeof(struct ec_host_request_i2c);
int response_header_size = sizeof(struct ec_host_response_i2c);
i2c_msg[0].addr = client->addr;
i2c_msg[0].flags = 0;
i2c_msg[1].addr = client->addr;
i2c_msg[1].flags = I2C_M_RD;
packet_len = msg->insize + response_header_size;
BUG_ON(packet_len > ec_dev->din_size);
in_buf = ec_dev->din;
i2c_msg[1].len = packet_len;
i2c_msg[1].buf = (char *) in_buf;
packet_len = msg->outsize + request_header_size;
BUG_ON(packet_len > ec_dev->dout_size);
out_buf = ec_dev->dout;
i2c_msg[0].len = packet_len;
i2c_msg[0].buf = (char *) out_buf;
/* create request data */
ec_request_i2c = (struct ec_host_request_i2c *) out_buf;
ec_request_i2c->command_protocol = EC_COMMAND_PROTOCOL_3;
ec_dev->dout++;
ret = cros_ec_prepare_tx(ec_dev, msg);
ec_dev->dout--;
/* send command to EC and read answer */
ret = i2c_transfer(client->adapter, i2c_msg, 2);
if (ret < 0) {
dev_dbg(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;
}
ec_response_i2c = (struct ec_host_response_i2c *) in_buf;
msg->result = ec_response_i2c->result;
ec_response = &ec_response_i2c->ec_response;
switch (msg->result) {
case EC_RES_SUCCESS:
break;
case EC_RES_IN_PROGRESS:
ret = -EAGAIN;
dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
msg->command);
goto done;
default:
dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
msg->command, msg->result);
/*
* When we send v3 request to v2 ec, ec won't recognize the
* 0xda (EC_COMMAND_PROTOCOL_3) and will return with status
* EC_RES_INVALID_COMMAND with zero data length.
*
* In case of invalid command for v3 protocol the data length
* will be at least sizeof(struct ec_host_response)
*/
if (ec_response_i2c->result == EC_RES_INVALID_COMMAND &&
ec_response_i2c->packet_length == 0) {
ret = -EPROTONOSUPPORT;
goto done;
}
}
if (ec_response_i2c->packet_length < sizeof(struct ec_host_response)) {
dev_err(ec_dev->dev,
"response of %u bytes too short; not a full header\n",
ec_response_i2c->packet_length);
ret = -EBADMSG;
goto done;
}
if (msg->insize < ec_response->data_len) {
dev_err(ec_dev->dev,
"response data size is too large: expected %u, got %u\n",
msg->insize,
ec_response->data_len);
ret = -EMSGSIZE;
goto done;
}
/* copy response packet payload and compute checksum */
sum = 0;
for (i = 0; i < sizeof(struct ec_host_response); i++)
sum += ((u8 *)ec_response)[i];
memcpy(msg->data,
in_buf + response_header_size,
ec_response->data_len);
for (i = 0; i < ec_response->data_len; i++)
sum += msg->data[i];
/* All bytes should sum to zero */
if (sum) {
dev_err(ec_dev->dev, "bad packet checksum\n");
ret = -EBADMSG;
goto done;
}
ret = ec_response->data_len;
done:
if (msg->command == EC_CMD_REBOOT_EC)
msleep(EC_REBOOT_DELAY_MS);
return ret;
}
static int cros_ec_cmd_xfer_i2c(struct cros_ec_device *ec_dev,
struct cros_ec_command *msg)
{
struct i2c_client *client = ec_dev->priv;
int ret = -ENOMEM;
int i;
int len;
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->insize + 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->outsize + 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->command;
out_buf[2] = msg->outsize;
/* copy message payload and compute checksum */
sum = out_buf[0] + out_buf[1] + out_buf[2];
for (i = 0; i < msg->outsize; i++) {
out_buf[3 + i] = msg->data[i];
sum += out_buf[3 + i];
}
out_buf[3 + msg->outsize] = 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 */
msg->result = i2c_msg[1].buf[0];
ret = cros_ec_check_result(ec_dev, msg);
if (ret)
goto done;
len = in_buf[1];
if (len > msg->insize) {
dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
len, msg->insize);
ret = -ENOSPC;
goto done;
}
/* copy response packet payload and compute checksum */
sum = in_buf[0] + in_buf[1];
for (i = 0; i < len; i++) {
msg->data[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 + len]) {
dev_err(ec_dev->dev, "bad packet checksum\n");
ret = -EBADMSG;
goto done;
}
ret = len;
done:
kfree(in_buf);
kfree(out_buf);
if (msg->command == EC_CMD_REBOOT_EC)
msleep(EC_REBOOT_DELAY_MS);
return ret;
}
static int cros_ec_i2c_probe(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->dev = dev;
ec_dev->priv = client;
ec_dev->irq = client->irq;
ec_dev->cmd_xfer = cros_ec_cmd_xfer_i2c;
ec_dev->pkt_xfer = cros_ec_pkt_xfer_i2c;
ec_dev->phys_name = client->adapter->name;
ec_dev->din_size = sizeof(struct ec_host_response_i2c) +
sizeof(struct ec_response_get_protocol_info);
ec_dev->dout_size = sizeof(struct ec_host_request_i2c);
err = cros_ec_register(ec_dev);
if (err) {
dev_err(dev, "cannot register EC\n");
return err;
}
return 0;
}
static int cros_ec_i2c_remove(struct i2c_client *client)
{
struct cros_ec_device *ec_dev = i2c_get_clientdata(client);
cros_ec_remove(ec_dev);
return 0;
}
#ifdef [31mCONFIG_PM_SLEEP[0m
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 of_device_id cros_ec_i2c_of_match[] = {
{ .compatible = "google,cros-ec-i2c", },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, cros_ec_i2c_of_match);
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",
.of_match_table = of_match_ptr(cros_ec_i2c_of_match),
.pm = &cros_ec_i2c_pm_ops,
},
.probe = cros_ec_i2c_probe,
.remove = cros_ec_i2c_remove,
.id_table = cros_ec_i2c_id,
};
module_i2c_driver(cros_ec_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ChromeOS EC multi function device");