![Krzysztof Kozlowski](/assets/img/avatar_default.png)
i2c_driver does not need to set an owner because i2c_register_driver() will set it. Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
367 lines
9 KiB
C
367 lines
9 KiB
C
/*
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* ChromeOS EC multi-function device (I2C)
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*
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* Copyright (C) 2012 Google, Inc
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/delay.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/interrupt.h>
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#include <linux/mfd/cros_ec.h>
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#include <linux/mfd/cros_ec_commands.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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/**
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* Request format for protocol v3
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* byte 0 0xda (EC_COMMAND_PROTOCOL_3)
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* byte 1-8 struct ec_host_request
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* byte 10- response data
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*/
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struct ec_host_request_i2c {
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/* Always 0xda to backward compatible with v2 struct */
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uint8_t command_protocol;
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struct ec_host_request ec_request;
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} __packed;
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/*
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* Response format for protocol v3
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* byte 0 result code
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* byte 1 packet_length
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* byte 2-9 struct ec_host_response
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* byte 10- response data
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*/
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struct ec_host_response_i2c {
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uint8_t result;
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uint8_t packet_length;
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struct ec_host_response ec_response;
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} __packed;
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static inline struct cros_ec_device *to_ec_dev(struct device *dev)
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{
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struct i2c_client *client = to_i2c_client(dev);
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return i2c_get_clientdata(client);
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}
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static int cros_ec_pkt_xfer_i2c(struct cros_ec_device *ec_dev,
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struct cros_ec_command *msg)
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{
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struct i2c_client *client = ec_dev->priv;
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int ret = -ENOMEM;
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int i;
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int packet_len;
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u8 *out_buf = NULL;
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u8 *in_buf = NULL;
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u8 sum;
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struct i2c_msg i2c_msg[2];
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struct ec_host_response *ec_response;
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struct ec_host_request_i2c *ec_request_i2c;
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struct ec_host_response_i2c *ec_response_i2c;
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int request_header_size = sizeof(struct ec_host_request_i2c);
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int response_header_size = sizeof(struct ec_host_response_i2c);
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i2c_msg[0].addr = client->addr;
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i2c_msg[0].flags = 0;
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i2c_msg[1].addr = client->addr;
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i2c_msg[1].flags = I2C_M_RD;
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packet_len = msg->insize + response_header_size;
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BUG_ON(packet_len > ec_dev->din_size);
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in_buf = ec_dev->din;
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i2c_msg[1].len = packet_len;
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i2c_msg[1].buf = (char *) in_buf;
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packet_len = msg->outsize + request_header_size;
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BUG_ON(packet_len > ec_dev->dout_size);
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out_buf = ec_dev->dout;
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i2c_msg[0].len = packet_len;
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i2c_msg[0].buf = (char *) out_buf;
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/* create request data */
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ec_request_i2c = (struct ec_host_request_i2c *) out_buf;
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ec_request_i2c->command_protocol = EC_COMMAND_PROTOCOL_3;
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ec_dev->dout++;
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ret = cros_ec_prepare_tx(ec_dev, msg);
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ec_dev->dout--;
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/* send command to EC and read answer */
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ret = i2c_transfer(client->adapter, i2c_msg, 2);
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if (ret < 0) {
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dev_dbg(ec_dev->dev, "i2c transfer failed: %d\n", ret);
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goto done;
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} else if (ret != 2) {
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dev_err(ec_dev->dev, "failed to get response: %d\n", ret);
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ret = -EIO;
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goto done;
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}
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ec_response_i2c = (struct ec_host_response_i2c *) in_buf;
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msg->result = ec_response_i2c->result;
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ec_response = &ec_response_i2c->ec_response;
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switch (msg->result) {
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case EC_RES_SUCCESS:
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break;
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case EC_RES_IN_PROGRESS:
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ret = -EAGAIN;
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dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
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msg->command);
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goto done;
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default:
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dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
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msg->command, msg->result);
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/*
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* When we send v3 request to v2 ec, ec won't recognize the
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* 0xda (EC_COMMAND_PROTOCOL_3) and will return with status
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* EC_RES_INVALID_COMMAND with zero data length.
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*
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* In case of invalid command for v3 protocol the data length
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* will be at least sizeof(struct ec_host_response)
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*/
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if (ec_response_i2c->result == EC_RES_INVALID_COMMAND &&
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ec_response_i2c->packet_length == 0) {
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ret = -EPROTONOSUPPORT;
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goto done;
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}
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}
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if (ec_response_i2c->packet_length < sizeof(struct ec_host_response)) {
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dev_err(ec_dev->dev,
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"response of %u bytes too short; not a full header\n",
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ec_response_i2c->packet_length);
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ret = -EBADMSG;
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goto done;
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}
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if (msg->insize < ec_response->data_len) {
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dev_err(ec_dev->dev,
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"response data size is too large: expected %u, got %u\n",
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msg->insize,
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ec_response->data_len);
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ret = -EMSGSIZE;
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goto done;
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}
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/* copy response packet payload and compute checksum */
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sum = 0;
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for (i = 0; i < sizeof(struct ec_host_response); i++)
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sum += ((u8 *)ec_response)[i];
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memcpy(msg->data,
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in_buf + response_header_size,
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ec_response->data_len);
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for (i = 0; i < ec_response->data_len; i++)
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sum += msg->data[i];
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/* All bytes should sum to zero */
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if (sum) {
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dev_err(ec_dev->dev, "bad packet checksum\n");
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ret = -EBADMSG;
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goto done;
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}
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ret = ec_response->data_len;
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done:
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if (msg->command == EC_CMD_REBOOT_EC)
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msleep(EC_REBOOT_DELAY_MS);
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return ret;
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}
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static int cros_ec_cmd_xfer_i2c(struct cros_ec_device *ec_dev,
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struct cros_ec_command *msg)
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{
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struct i2c_client *client = ec_dev->priv;
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int ret = -ENOMEM;
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int i;
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int len;
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int packet_len;
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u8 *out_buf = NULL;
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u8 *in_buf = NULL;
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u8 sum;
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struct i2c_msg i2c_msg[2];
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i2c_msg[0].addr = client->addr;
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i2c_msg[0].flags = 0;
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i2c_msg[1].addr = client->addr;
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i2c_msg[1].flags = I2C_M_RD;
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/*
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* allocate larger packet (one byte for checksum, one byte for
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* length, and one for result code)
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*/
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packet_len = msg->insize + 3;
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in_buf = kzalloc(packet_len, GFP_KERNEL);
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if (!in_buf)
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goto done;
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i2c_msg[1].len = packet_len;
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i2c_msg[1].buf = (char *)in_buf;
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/*
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* allocate larger packet (one byte for checksum, one for
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* command code, one for length, and one for command version)
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*/
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packet_len = msg->outsize + 4;
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out_buf = kzalloc(packet_len, GFP_KERNEL);
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if (!out_buf)
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goto done;
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i2c_msg[0].len = packet_len;
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i2c_msg[0].buf = (char *)out_buf;
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out_buf[0] = EC_CMD_VERSION0 + msg->version;
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out_buf[1] = msg->command;
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out_buf[2] = msg->outsize;
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/* copy message payload and compute checksum */
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sum = out_buf[0] + out_buf[1] + out_buf[2];
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for (i = 0; i < msg->outsize; i++) {
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out_buf[3 + i] = msg->data[i];
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sum += out_buf[3 + i];
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}
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out_buf[3 + msg->outsize] = sum;
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/* send command to EC and read answer */
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ret = i2c_transfer(client->adapter, i2c_msg, 2);
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if (ret < 0) {
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dev_err(ec_dev->dev, "i2c transfer failed: %d\n", ret);
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goto done;
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} else if (ret != 2) {
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dev_err(ec_dev->dev, "failed to get response: %d\n", ret);
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ret = -EIO;
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goto done;
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}
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/* check response error code */
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msg->result = i2c_msg[1].buf[0];
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ret = cros_ec_check_result(ec_dev, msg);
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if (ret)
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goto done;
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len = in_buf[1];
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if (len > msg->insize) {
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dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
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len, msg->insize);
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ret = -ENOSPC;
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goto done;
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}
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/* copy response packet payload and compute checksum */
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sum = in_buf[0] + in_buf[1];
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for (i = 0; i < len; i++) {
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msg->data[i] = in_buf[2 + i];
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sum += in_buf[2 + i];
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}
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dev_dbg(ec_dev->dev, "packet: %*ph, sum = %02x\n",
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i2c_msg[1].len, in_buf, sum);
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if (sum != in_buf[2 + len]) {
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dev_err(ec_dev->dev, "bad packet checksum\n");
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ret = -EBADMSG;
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goto done;
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}
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ret = len;
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done:
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kfree(in_buf);
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kfree(out_buf);
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if (msg->command == EC_CMD_REBOOT_EC)
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msleep(EC_REBOOT_DELAY_MS);
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return ret;
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}
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static int cros_ec_i2c_probe(struct i2c_client *client,
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const struct i2c_device_id *dev_id)
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{
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struct device *dev = &client->dev;
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struct cros_ec_device *ec_dev = NULL;
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int err;
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ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
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if (!ec_dev)
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return -ENOMEM;
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i2c_set_clientdata(client, ec_dev);
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ec_dev->dev = dev;
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ec_dev->priv = client;
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ec_dev->irq = client->irq;
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ec_dev->cmd_xfer = cros_ec_cmd_xfer_i2c;
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ec_dev->pkt_xfer = cros_ec_pkt_xfer_i2c;
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ec_dev->phys_name = client->adapter->name;
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ec_dev->din_size = sizeof(struct ec_host_response_i2c) +
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sizeof(struct ec_response_get_protocol_info);
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ec_dev->dout_size = sizeof(struct ec_host_request_i2c);
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err = cros_ec_register(ec_dev);
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if (err) {
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dev_err(dev, "cannot register EC\n");
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return err;
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}
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return 0;
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}
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static int cros_ec_i2c_remove(struct i2c_client *client)
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{
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struct cros_ec_device *ec_dev = i2c_get_clientdata(client);
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cros_ec_remove(ec_dev);
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return 0;
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}
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#ifdef CONFIG_PM_SLEEP
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static int cros_ec_i2c_suspend(struct device *dev)
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{
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struct cros_ec_device *ec_dev = to_ec_dev(dev);
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return cros_ec_suspend(ec_dev);
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}
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static int cros_ec_i2c_resume(struct device *dev)
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{
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struct cros_ec_device *ec_dev = to_ec_dev(dev);
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return cros_ec_resume(ec_dev);
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}
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#endif
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static SIMPLE_DEV_PM_OPS(cros_ec_i2c_pm_ops, cros_ec_i2c_suspend,
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cros_ec_i2c_resume);
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static const struct i2c_device_id cros_ec_i2c_id[] = {
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{ "cros-ec-i2c", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, cros_ec_i2c_id);
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static struct i2c_driver cros_ec_driver = {
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.driver = {
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.name = "cros-ec-i2c",
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.pm = &cros_ec_i2c_pm_ops,
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},
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.probe = cros_ec_i2c_probe,
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.remove = cros_ec_i2c_remove,
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.id_table = cros_ec_i2c_id,
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};
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module_i2c_driver(cros_ec_driver);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("ChromeOS EC multi function device");
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