1 // SPDX-License-Identifier: GPL-2.0 2 // I2C interface for ChromeOS Embedded Controller 3 // 4 // Copyright (C) 2012 Google, Inc 5 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 v3 21 * byte 0 0xda (EC_COMMAND_PROTOCOL_3) 22 * byte 1-8 struct ec_host_request 23 * byte 10- response data 24 */ 25 struct 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 v3 34 * byte 0 result code 35 * byte 1 packet_length 36 * byte 2-9 struct ec_host_response 37 * byte 10- response data 38 */ 39 struct ec_host_response_i2c { 40 uint8_t result; 41 uint8_t packet_length; 42 struct ec_host_response ec_response; 43 } __packed; 44 45 static 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 52 static 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 the 131 * 0xda (EC_COMMAND_PROTOCOL_3) and will return with status 132 * EC_RES_INVALID_COMMAND with zero data length. 133 * 134 * In case of invalid command for v3 protocol the data length 135 * 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; 180 181 done: 182 if (msg->command == EC_CMD_REBOOT_EC) 183 msleep(EC_REBOOT_DELAY_MS); 184 185 return ret; 186 } 187 188 static 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 for 208 * 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 for 219 * 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; 280 done: 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 } 288 289 static 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 } 318 319 static 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_SLEEP 327 static 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 } 333 334 static 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 #endif 341 342 static 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_OF 347 static const struct of_device_id cros_ec_i2c_of_match[] = { 348 { .compatible = "google,cros-ec-i2c", }, 349 { /* sentinel */ }, 350 }; 351 MODULE_DEVICE_TABLE(of, cros_ec_i2c_of_match); 352 #endif 353 354 static const struct i2c_device_id cros_ec_i2c_id[] = { 355 { "cros-ec-i2c", 0 }, 356 { } 357 }; 358 MODULE_DEVICE_TABLE(i2c, cros_ec_i2c_id); 359 360 #ifdef CONFIG_ACPI 361 static const struct acpi_device_id cros_ec_i2c_acpi_id[] = { 362 { "GOOG0008", 0 }, 363 { /* sentinel */ } 364 }; 365 MODULE_DEVICE_TABLE(acpi, cros_ec_i2c_acpi_id); 366 #endif 367 368 static 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 }; 379 380 module_i2c_driver(cros_ec_driver); 381 382 MODULE_LICENSE("GPL v2"); 383 MODULE_DESCRIPTION("I2C interface for ChromeOS Embedded Controller"); 384