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1// SPDX-License-Identifier: GPL-2.02// I2C interface for ChromeOS Embedded Controller3//4// Copyright (C) 2012 Google, Inc5 6#include <linux/acpi.h>7#include <linux/delay.h>8#include <linux/kernel.h>9#include <linux/module.h>10#include <linux/i2c.h>11#include <linux/interrupt.h>12#include <linux/platform_data/cros_ec_commands.h>13#include <linux/platform_data/cros_ec_proto.h>14#include <linux/platform_device.h>15#include <linux/slab.h>16 17#include "cros_ec.h"18 19/*20 * Request format for protocol v321 * byte 0 0xda (EC_COMMAND_PROTOCOL_3)22 * byte 1-8 struct ec_host_request23 * byte 10- response data24 */25struct ec_host_request_i2c {26 /* Always 0xda to backward compatible with v2 struct */27 uint8_t command_protocol;28 struct ec_host_request ec_request;29} __packed;30 31 32/*33 * Response format for protocol v334 * byte 0 result code35 * byte 1 packet_length36 * byte 2-9 struct ec_host_response37 * byte 10- response data38 */39struct ec_host_response_i2c {40 uint8_t result;41 uint8_t packet_length;42 struct ec_host_response ec_response;43} __packed;44 45static inline struct cros_ec_device *to_ec_dev(struct device *dev)46{47 struct i2c_client *client = to_i2c_client(dev);48 49 return i2c_get_clientdata(client);50}51 52static int cros_ec_pkt_xfer_i2c(struct cros_ec_device *ec_dev,53 struct cros_ec_command *msg)54{55 struct i2c_client *client = ec_dev->priv;56 int ret = -ENOMEM;57 int i;58 int packet_len;59 u8 *out_buf = NULL;60 u8 *in_buf = NULL;61 u8 sum;62 struct i2c_msg i2c_msg[2];63 struct ec_host_response *ec_response;64 struct ec_host_request_i2c *ec_request_i2c;65 struct ec_host_response_i2c *ec_response_i2c;66 int request_header_size = sizeof(struct ec_host_request_i2c);67 int response_header_size = sizeof(struct ec_host_response_i2c);68 69 i2c_msg[0].addr = client->addr;70 i2c_msg[0].flags = 0;71 i2c_msg[1].addr = client->addr;72 i2c_msg[1].flags = I2C_M_RD;73 74 packet_len = msg->insize + response_header_size;75 if (packet_len > ec_dev->din_size) {76 ret = -EINVAL;77 goto done;78 }79 in_buf = ec_dev->din;80 i2c_msg[1].len = packet_len;81 i2c_msg[1].buf = (char *) in_buf;82 83 packet_len = msg->outsize + request_header_size;84 if (packet_len > ec_dev->dout_size) {85 ret = -EINVAL;86 goto done;87 }88 out_buf = ec_dev->dout;89 i2c_msg[0].len = packet_len;90 i2c_msg[0].buf = (char *) out_buf;91 92 /* create request data */93 ec_request_i2c = (struct ec_host_request_i2c *) out_buf;94 ec_request_i2c->command_protocol = EC_COMMAND_PROTOCOL_3;95 96 ec_dev->dout++;97 ret = cros_ec_prepare_tx(ec_dev, msg);98 if (ret < 0)99 goto done;100 ec_dev->dout--;101 102 /* send command to EC and read answer */103 ret = i2c_transfer(client->adapter, i2c_msg, 2);104 if (ret < 0) {105 dev_dbg(ec_dev->dev, "i2c transfer failed: %d\n", ret);106 goto done;107 } else if (ret != 2) {108 dev_err(ec_dev->dev, "failed to get response: %d\n", ret);109 ret = -EIO;110 goto done;111 }112 113 ec_response_i2c = (struct ec_host_response_i2c *) in_buf;114 msg->result = ec_response_i2c->result;115 ec_response = &ec_response_i2c->ec_response;116 117 switch (msg->result) {118 case EC_RES_SUCCESS:119 break;120 case EC_RES_IN_PROGRESS:121 ret = -EAGAIN;122 dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",123 msg->command);124 goto done;125 126 default:127 dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",128 msg->command, msg->result);129 /*130 * When we send v3 request to v2 ec, ec won't recognize the131 * 0xda (EC_COMMAND_PROTOCOL_3) and will return with status132 * EC_RES_INVALID_COMMAND with zero data length.133 *134 * In case of invalid command for v3 protocol the data length135 * will be at least sizeof(struct ec_host_response)136 */137 if (ec_response_i2c->result == EC_RES_INVALID_COMMAND &&138 ec_response_i2c->packet_length == 0) {139 ret = -EPROTONOSUPPORT;140 goto done;141 }142 }143 144 if (ec_response_i2c->packet_length < sizeof(struct ec_host_response)) {145 dev_err(ec_dev->dev,146 "response of %u bytes too short; not a full header\n",147 ec_response_i2c->packet_length);148 ret = -EBADMSG;149 goto done;150 }151 152 if (msg->insize < ec_response->data_len) {153 dev_err(ec_dev->dev,154 "response data size is too large: expected %u, got %u\n",155 msg->insize,156 ec_response->data_len);157 ret = -EMSGSIZE;158 goto done;159 }160 161 /* copy response packet payload and compute checksum */162 sum = 0;163 for (i = 0; i < sizeof(struct ec_host_response); i++)164 sum += ((u8 *)ec_response)[i];165 166 memcpy(msg->data,167 in_buf + response_header_size,168 ec_response->data_len);169 for (i = 0; i < ec_response->data_len; i++)170 sum += msg->data[i];171 172 /* All bytes should sum to zero */173 if (sum) {174 dev_err(ec_dev->dev, "bad packet checksum\n");175 ret = -EBADMSG;176 goto done;177 }178 179 ret = ec_response->data_len;180 181done:182 if (msg->command == EC_CMD_REBOOT_EC)183 msleep(EC_REBOOT_DELAY_MS);184 185 return ret;186}187 188static int cros_ec_cmd_xfer_i2c(struct cros_ec_device *ec_dev,189 struct cros_ec_command *msg)190{191 struct i2c_client *client = ec_dev->priv;192 int ret = -ENOMEM;193 int i;194 int len;195 int packet_len;196 u8 *out_buf = NULL;197 u8 *in_buf = NULL;198 u8 sum;199 struct i2c_msg i2c_msg[2];200 201 i2c_msg[0].addr = client->addr;202 i2c_msg[0].flags = 0;203 i2c_msg[1].addr = client->addr;204 i2c_msg[1].flags = I2C_M_RD;205 206 /*207 * allocate larger packet (one byte for checksum, one byte for208 * length, and one for result code)209 */210 packet_len = msg->insize + 3;211 in_buf = kzalloc(packet_len, GFP_KERNEL);212 if (!in_buf)213 goto done;214 i2c_msg[1].len = packet_len;215 i2c_msg[1].buf = (char *)in_buf;216 217 /*218 * allocate larger packet (one byte for checksum, one for219 * command code, one for length, and one for command version)220 */221 packet_len = msg->outsize + 4;222 out_buf = kzalloc(packet_len, GFP_KERNEL);223 if (!out_buf)224 goto done;225 i2c_msg[0].len = packet_len;226 i2c_msg[0].buf = (char *)out_buf;227 228 out_buf[0] = EC_CMD_VERSION0 + msg->version;229 out_buf[1] = msg->command;230 out_buf[2] = msg->outsize;231 232 /* copy message payload and compute checksum */233 sum = out_buf[0] + out_buf[1] + out_buf[2];234 for (i = 0; i < msg->outsize; i++) {235 out_buf[3 + i] = msg->data[i];236 sum += out_buf[3 + i];237 }238 out_buf[3 + msg->outsize] = sum;239 240 /* send command to EC and read answer */241 ret = i2c_transfer(client->adapter, i2c_msg, 2);242 if (ret < 0) {243 dev_err(ec_dev->dev, "i2c transfer failed: %d\n", ret);244 goto done;245 } else if (ret != 2) {246 dev_err(ec_dev->dev, "failed to get response: %d\n", ret);247 ret = -EIO;248 goto done;249 }250 251 /* check response error code */252 msg->result = i2c_msg[1].buf[0];253 ret = cros_ec_check_result(ec_dev, msg);254 if (ret)255 goto done;256 257 len = in_buf[1];258 if (len > msg->insize) {259 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",260 len, msg->insize);261 ret = -ENOSPC;262 goto done;263 }264 265 /* copy response packet payload and compute checksum */266 sum = in_buf[0] + in_buf[1];267 for (i = 0; i < len; i++) {268 msg->data[i] = in_buf[2 + i];269 sum += in_buf[2 + i];270 }271 dev_dbg(ec_dev->dev, "packet: %*ph, sum = %02x\n",272 i2c_msg[1].len, in_buf, sum);273 if (sum != in_buf[2 + len]) {274 dev_err(ec_dev->dev, "bad packet checksum\n");275 ret = -EBADMSG;276 goto done;277 }278 279 ret = len;280done:281 kfree(in_buf);282 kfree(out_buf);283 if (msg->command == EC_CMD_REBOOT_EC)284 msleep(EC_REBOOT_DELAY_MS);285 286 return ret;287}288 289static int cros_ec_i2c_probe(struct i2c_client *client)290{291 struct device *dev = &client->dev;292 struct cros_ec_device *ec_dev = NULL;293 int err;294 295 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);296 if (!ec_dev)297 return -ENOMEM;298 299 i2c_set_clientdata(client, ec_dev);300 ec_dev->dev = dev;301 ec_dev->priv = client;302 ec_dev->irq = client->irq;303 ec_dev->cmd_xfer = cros_ec_cmd_xfer_i2c;304 ec_dev->pkt_xfer = cros_ec_pkt_xfer_i2c;305 ec_dev->phys_name = client->adapter->name;306 ec_dev->din_size = sizeof(struct ec_host_response_i2c) +307 sizeof(struct ec_response_get_protocol_info);308 ec_dev->dout_size = sizeof(struct ec_host_request_i2c);309 310 err = cros_ec_register(ec_dev);311 if (err) {312 dev_err(dev, "cannot register EC\n");313 return err;314 }315 316 return 0;317}318 319static void cros_ec_i2c_remove(struct i2c_client *client)320{321 struct cros_ec_device *ec_dev = i2c_get_clientdata(client);322 323 cros_ec_unregister(ec_dev);324}325 326#ifdef CONFIG_PM_SLEEP327static int cros_ec_i2c_suspend(struct device *dev)328{329 struct cros_ec_device *ec_dev = to_ec_dev(dev);330 331 return cros_ec_suspend(ec_dev);332}333 334static int cros_ec_i2c_resume(struct device *dev)335{336 struct cros_ec_device *ec_dev = to_ec_dev(dev);337 338 return cros_ec_resume(ec_dev);339}340#endif341 342static const struct dev_pm_ops cros_ec_i2c_pm_ops = {343 SET_LATE_SYSTEM_SLEEP_PM_OPS(cros_ec_i2c_suspend, cros_ec_i2c_resume)344};345 346#ifdef CONFIG_OF347static const struct of_device_id cros_ec_i2c_of_match[] = {348 { .compatible = "google,cros-ec-i2c", },349 { /* sentinel */ },350};351MODULE_DEVICE_TABLE(of, cros_ec_i2c_of_match);352#endif353 354static const struct i2c_device_id cros_ec_i2c_id[] = {355 { "cros-ec-i2c", 0 },356 { }357};358MODULE_DEVICE_TABLE(i2c, cros_ec_i2c_id);359 360#ifdef CONFIG_ACPI361static const struct acpi_device_id cros_ec_i2c_acpi_id[] = {362 { "GOOG0008", 0 },363 { /* sentinel */ }364};365MODULE_DEVICE_TABLE(acpi, cros_ec_i2c_acpi_id);366#endif367 368static struct i2c_driver cros_ec_driver = {369 .driver = {370 .name = "cros-ec-i2c",371 .acpi_match_table = ACPI_PTR(cros_ec_i2c_acpi_id),372 .of_match_table = of_match_ptr(cros_ec_i2c_of_match),373 .pm = &cros_ec_i2c_pm_ops,374 },375 .probe = cros_ec_i2c_probe,376 .remove = cros_ec_i2c_remove,377 .id_table = cros_ec_i2c_id,378};379 380module_i2c_driver(cros_ec_driver);381 382MODULE_LICENSE("GPL v2");383MODULE_DESCRIPTION("I2C interface for ChromeOS Embedded Controller");384