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376 lines
9.1 KiB
376 lines
9.1 KiB
// SPDX-License-Identifier: GPL-2.0 |
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// I2C interface for ChromeOS Embedded Controller |
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// |
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// Copyright (C) 2012 Google, Inc |
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#include <linux/acpi.h> |
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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/platform_data/cros_ec_commands.h> |
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#include <linux/platform_data/cros_ec_proto.h> |
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#include <linux/platform_device.h> |
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#include <linux/slab.h> |
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#include "cros_ec.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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return cros_ec_unregister(ec_dev); |
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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 const struct dev_pm_ops cros_ec_i2c_pm_ops = { |
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SET_LATE_SYSTEM_SLEEP_PM_OPS(cros_ec_i2c_suspend, cros_ec_i2c_resume) |
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}; |
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#ifdef CONFIG_OF |
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static const struct of_device_id cros_ec_i2c_of_match[] = { |
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{ .compatible = "google,cros-ec-i2c", }, |
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{ /* sentinel */ }, |
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}; |
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MODULE_DEVICE_TABLE(of, cros_ec_i2c_of_match); |
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#endif |
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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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#ifdef CONFIG_ACPI |
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static const struct acpi_device_id cros_ec_i2c_acpi_id[] = { |
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{ "GOOG0008", 0 }, |
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{ /* sentinel */ } |
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}; |
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MODULE_DEVICE_TABLE(acpi, cros_ec_i2c_acpi_id); |
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#endif |
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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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.acpi_match_table = ACPI_PTR(cros_ec_i2c_acpi_id), |
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.of_match_table = of_match_ptr(cros_ec_i2c_of_match), |
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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 v2"); |
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MODULE_DESCRIPTION("I2C interface for ChromeOS Embedded Controller");
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