1 // SPDX-License-Identifier: GPL-2.0+
2 // Expose an I2C passthrough to the ChromeOS EC.
8 #include <linux/i2c.h>
17  * struct ec_i2c_device - Driver data for I2C tunnel
20  * @adap: I2C adapter
22  * @remote_bus: The EC bus number we tunnel to on the other side.
39  * ec_i2c_count_message - Count bytes needed for ec_i2c_construct_message
41  * @i2c_msgs: The i2c messages to read
42  * @num: The number of i2c messages.
61  * ec_i2c_construct_message - construct a message to go to the EC
67  * @i2c_msgs: The i2c messages to read.
68  * @num: The number of i2c messages.
69  * @bus_num: The remote bus number we want to talk to.
84 	params->port = bus_num;  in ec_i2c_construct_message()
85 	params->num_msgs = num;  in ec_i2c_construct_message()
88 		struct ec_params_i2c_passthru_msg *msg = &params->msg[i];  in ec_i2c_construct_message()
90 		msg->len = i2c_msg->len;  in ec_i2c_construct_message()
91 		msg->addr_flags = i2c_msg->addr;  in ec_i2c_construct_message()
93 		if (i2c_msg->flags & I2C_M_TEN)  in ec_i2c_construct_message()
94 			return -EINVAL;  in ec_i2c_construct_message()
96 		if (i2c_msg->flags & I2C_M_RD) {  in ec_i2c_construct_message()
97 			msg->addr_flags |= EC_I2C_FLAG_READ;  in ec_i2c_construct_message()
99 			memcpy(out_data, i2c_msg->buf, msg->len);  in ec_i2c_construct_message()
100 			out_data += msg->len;  in ec_i2c_construct_message()
108  * ec_i2c_count_response - Count bytes needed for ec_i2c_parse_response
110  * @i2c_msgs: The i2c messages to fill up.
111  * @num: The number of i2c messages expected.
129  * ec_i2c_parse_response - Parse a response from the EC
134  * @i2c_msgs: The i2c messages to fill up.
135  * @num: The number of i2c messages; will be modified to include the actual
150 	if (resp->i2c_status & EC_I2C_STATUS_TIMEOUT)  in ec_i2c_parse_response()
151 		return -ETIMEDOUT;  in ec_i2c_parse_response()
152 	else if (resp->i2c_status & EC_I2C_STATUS_NAK)  in ec_i2c_parse_response()
153 		return -ENXIO;  in ec_i2c_parse_response()
154 	else if (resp->i2c_status & EC_I2C_STATUS_ERROR)  in ec_i2c_parse_response()
155 		return -EIO;  in ec_i2c_parse_response()
158 	if (resp->num_msgs > *num)  in ec_i2c_parse_response()
159 		return -EPROTO;  in ec_i2c_parse_response()
160 	*num = resp->num_msgs;  in ec_i2c_parse_response()
166 			memcpy(i2c_msg->buf, in_data, i2c_msg->len);  in ec_i2c_parse_response()
167 			in_data += i2c_msg->len;  in ec_i2c_parse_response()
177 	struct ec_i2c_device *bus = adap->algo_data;  in ec_i2c_xfer()  local
178 	struct device *dev = bus->dev;  in ec_i2c_xfer()
179 	const u16 bus_num = bus->remote_bus;  in ec_i2c_xfer()
202 		return -ENOMEM;  in ec_i2c_xfer()
204 	result = ec_i2c_construct_message(msg->data, i2c_msgs, num, bus_num);  in ec_i2c_xfer()
206 		dev_err(dev, "Error constructing EC i2c message %d\n", result);  in ec_i2c_xfer()
210 	msg->version = 0;  in ec_i2c_xfer()
211 	msg->command = EC_CMD_I2C_PASSTHRU;  in ec_i2c_xfer()
212 	msg->outsize = request_len;  in ec_i2c_xfer()
213 	msg->insize = response_len;  in ec_i2c_xfer()
215 	result = cros_ec_cmd_xfer_status(bus->ec, msg);  in ec_i2c_xfer()
217 		dev_err(dev, "Error transferring EC i2c message %d\n", result);  in ec_i2c_xfer()
221 	result = ec_i2c_parse_response(msg->data, i2c_msgs, &num);  in ec_i2c_xfer()
244 	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);  in ec_i2c_probe()
245 	struct device *dev = &pdev->dev;  in ec_i2c_probe()
246 	struct ec_i2c_device *bus = NULL;  in ec_i2c_probe()  local
250 	if (!ec->cmd_xfer) {  in ec_i2c_probe()
252 		return -EINVAL;  in ec_i2c_probe()
255 	bus = devm_kzalloc(dev, sizeof(*bus), GFP_KERNEL);  in ec_i2c_probe()
256 	if (bus == NULL)  in ec_i2c_probe()
257 		return -ENOMEM;  in ec_i2c_probe()
259 	err = device_property_read_u32(dev, "google,remote-bus", &remote_bus);  in ec_i2c_probe()
261 		dev_err(dev, "Couldn't read remote-bus property\n");  in ec_i2c_probe()
264 	bus->remote_bus = remote_bus;  in ec_i2c_probe()
266 	bus->ec = ec;  in ec_i2c_probe()
267 	bus->dev = dev;  in ec_i2c_probe()
269 	bus->adap.owner = THIS_MODULE;  in ec_i2c_probe()
270 	strscpy(bus->adap.name, "cros-ec-i2c-tunnel", sizeof(bus->adap.name));  in ec_i2c_probe()
271 	bus->adap.algo = &ec_i2c_algorithm;  in ec_i2c_probe()
272 	bus->adap.algo_data = bus;  in ec_i2c_probe()
273 	bus->adap.dev.parent = &pdev->dev;  in ec_i2c_probe()
274 	bus->adap.dev.of_node = pdev->dev.of_node;  in ec_i2c_probe()
275 	bus->adap.retries = I2C_MAX_RETRIES;  in ec_i2c_probe()
276 	ACPI_COMPANION_SET(&bus->adap.dev, ACPI_COMPANION(&pdev->dev));  in ec_i2c_probe()
278 	err = i2c_add_adapter(&bus->adap);  in ec_i2c_probe()
281 	platform_set_drvdata(pdev, bus);  in ec_i2c_probe()
288 	struct ec_i2c_device *bus = platform_get_drvdata(dev);  in ec_i2c_remove()  local
290 	i2c_del_adapter(&bus->adap);  in ec_i2c_remove()
294 	{ .compatible = "google,cros-ec-i2c-tunnel" },
309 		.name = "cros-ec-i2c-tunnel",
318 MODULE_DESCRIPTION("EC I2C tunnel driver");
319 MODULE_ALIAS("platform:cros-ec-i2c-tunnel");