| /* | 
 |  * 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 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 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"); |