1 files changed, 386 insertions, 0 deletions
diff --git a/drivers/platform/chrome/cros_ec_i2c.c b/drivers/platform/chrome/cros_ec_i2c.c
new file mode 100644
index 000000000000..ef9b4763356f
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_i2c.c
@@ -0,0 +1,386 @@
+/*
+ * 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/acpi.h>
+#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 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");
+MODULE_DESCRIPTION("ChromeOS EC multi function device");