| // SPDX-License-Identifier: GPL-2.0 |
| // I2C interface for ChromeOS Embedded Controller |
| // |
| // Copyright (C) 2012 Google, Inc |
| |
| #include <linux/acpi.h> |
| #include <linux/delay.h> |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/i2c.h> |
| #include <linux/interrupt.h> |
| #include <linux/platform_data/cros_ec_commands.h> |
| #include <linux/platform_data/cros_ec_proto.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); |
| |
| return cros_ec_unregister(ec_dev); |
| } |
| |
| #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 const struct dev_pm_ops cros_ec_i2c_pm_ops = { |
| SET_LATE_SYSTEM_SLEEP_PM_OPS(cros_ec_i2c_suspend, cros_ec_i2c_resume) |
| }; |
| |
| #ifdef CONFIG_OF |
| 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); |
| #endif |
| |
| static const struct i2c_device_id cros_ec_i2c_id[] = { |
| { "cros-ec-i2c", 0 }, |
| { } |
| }; |
| MODULE_DEVICE_TABLE(i2c, cros_ec_i2c_id); |
| |
| #ifdef CONFIG_ACPI |
| static const struct acpi_device_id cros_ec_i2c_acpi_id[] = { |
| { "GOOG0008", 0 }, |
| { /* sentinel */ } |
| }; |
| MODULE_DEVICE_TABLE(acpi, cros_ec_i2c_acpi_id); |
| #endif |
| |
| static struct i2c_driver cros_ec_driver = { |
| .driver = { |
| .name = "cros-ec-i2c", |
| .acpi_match_table = ACPI_PTR(cros_ec_i2c_acpi_id), |
| .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 v2"); |
| MODULE_DESCRIPTION("I2C interface for ChromeOS Embedded Controller"); |