1 /* 2 * ChromeOS EC multi-function device (I2C) 3 * 4 * Copyright (C) 2012 Google, Inc 5 * 6 * This software is licensed under the terms of the GNU General Public 7 * License version 2, as published by the Free Software Foundation, and 8 * may be copied, distributed, and modified under those terms. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 */ 15 16 #include <linux/acpi.h> 17 #include <linux/delay.h> 18 #include <linux/kernel.h> 19 #include <linux/module.h> 20 #include <linux/i2c.h> 21 #include <linux/interrupt.h> 22 #include <linux/mfd/cros_ec.h> 23 #include <linux/mfd/cros_ec_commands.h> 24 #include <linux/platform_device.h> 25 #include <linux/slab.h> 26 27 /** 28 * Request format for protocol v3 29 * byte 0 0xda (EC_COMMAND_PROTOCOL_3) 30 * byte 1-8 struct ec_host_request 31 * byte 10- response data 32 */ 33 struct ec_host_request_i2c { 34 /* Always 0xda to backward compatible with v2 struct */ 35 uint8_t command_protocol; 36 struct ec_host_request ec_request; 37 } __packed; 38 39 40 /* 41 * Response format for protocol v3 42 * byte 0 result code 43 * byte 1 packet_length 44 * byte 2-9 struct ec_host_response 45 * byte 10- response data 46 */ 47 struct ec_host_response_i2c { 48 uint8_t result; 49 uint8_t packet_length; 50 struct ec_host_response ec_response; 51 } __packed; 52 53 static inline struct cros_ec_device *to_ec_dev(struct device *dev) 54 { 55 struct i2c_client *client = to_i2c_client(dev); 56 57 return i2c_get_clientdata(client); 58 } 59 60 static int cros_ec_pkt_xfer_i2c(struct cros_ec_device *ec_dev, 61 struct cros_ec_command *msg) 62 { 63 struct i2c_client *client = ec_dev->priv; 64 int ret = -ENOMEM; 65 int i; 66 int packet_len; 67 u8 *out_buf = NULL; 68 u8 *in_buf = NULL; 69 u8 sum; 70 struct i2c_msg i2c_msg[2]; 71 struct ec_host_response *ec_response; 72 struct ec_host_request_i2c *ec_request_i2c; 73 struct ec_host_response_i2c *ec_response_i2c; 74 int request_header_size = sizeof(struct ec_host_request_i2c); 75 int response_header_size = sizeof(struct ec_host_response_i2c); 76 77 i2c_msg[0].addr = client->addr; 78 i2c_msg[0].flags = 0; 79 i2c_msg[1].addr = client->addr; 80 i2c_msg[1].flags = I2C_M_RD; 81 82 packet_len = msg->insize + response_header_size; 83 BUG_ON(packet_len > ec_dev->din_size); 84 in_buf = ec_dev->din; 85 i2c_msg[1].len = packet_len; 86 i2c_msg[1].buf = (char *) in_buf; 87 88 packet_len = msg->outsize + request_header_size; 89 BUG_ON(packet_len > ec_dev->dout_size); 90 out_buf = ec_dev->dout; 91 i2c_msg[0].len = packet_len; 92 i2c_msg[0].buf = (char *) out_buf; 93 94 /* create request data */ 95 ec_request_i2c = (struct ec_host_request_i2c *) out_buf; 96 ec_request_i2c->command_protocol = EC_COMMAND_PROTOCOL_3; 97 98 ec_dev->dout++; 99 ret = cros_ec_prepare_tx(ec_dev, msg); 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 const struct i2c_device_id *dev_id) 291 { 292 struct device *dev = &client->dev; 293 struct cros_ec_device *ec_dev = NULL; 294 int err; 295 296 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); 297 if (!ec_dev) 298 return -ENOMEM; 299 300 i2c_set_clientdata(client, ec_dev); 301 ec_dev->dev = dev; 302 ec_dev->priv = client; 303 ec_dev->irq = client->irq; 304 ec_dev->cmd_xfer = cros_ec_cmd_xfer_i2c; 305 ec_dev->pkt_xfer = cros_ec_pkt_xfer_i2c; 306 ec_dev->phys_name = client->adapter->name; 307 ec_dev->din_size = sizeof(struct ec_host_response_i2c) + 308 sizeof(struct ec_response_get_protocol_info); 309 ec_dev->dout_size = sizeof(struct ec_host_request_i2c); 310 311 err = cros_ec_register(ec_dev); 312 if (err) { 313 dev_err(dev, "cannot register EC\n"); 314 return err; 315 } 316 317 return 0; 318 } 319 320 static int cros_ec_i2c_remove(struct i2c_client *client) 321 { 322 struct cros_ec_device *ec_dev = i2c_get_clientdata(client); 323 324 cros_ec_remove(ec_dev); 325 326 return 0; 327 } 328 329 #ifdef CONFIG_PM_SLEEP 330 static int cros_ec_i2c_suspend(struct device *dev) 331 { 332 struct cros_ec_device *ec_dev = to_ec_dev(dev); 333 334 return cros_ec_suspend(ec_dev); 335 } 336 337 static int cros_ec_i2c_resume(struct device *dev) 338 { 339 struct cros_ec_device *ec_dev = to_ec_dev(dev); 340 341 return cros_ec_resume(ec_dev); 342 } 343 #endif 344 345 static const struct dev_pm_ops cros_ec_i2c_pm_ops = { 346 SET_LATE_SYSTEM_SLEEP_PM_OPS(cros_ec_i2c_suspend, cros_ec_i2c_resume) 347 }; 348 349 #ifdef CONFIG_OF 350 static const struct of_device_id cros_ec_i2c_of_match[] = { 351 { .compatible = "google,cros-ec-i2c", }, 352 { /* sentinel */ }, 353 }; 354 MODULE_DEVICE_TABLE(of, cros_ec_i2c_of_match); 355 #endif 356 357 static const struct i2c_device_id cros_ec_i2c_id[] = { 358 { "cros-ec-i2c", 0 }, 359 { } 360 }; 361 MODULE_DEVICE_TABLE(i2c, cros_ec_i2c_id); 362 363 #ifdef CONFIG_ACPI 364 static const struct acpi_device_id cros_ec_i2c_acpi_id[] = { 365 { "GOOG0008", 0 }, 366 { /* sentinel */ } 367 }; 368 MODULE_DEVICE_TABLE(acpi, cros_ec_i2c_acpi_id); 369 #endif 370 371 static struct i2c_driver cros_ec_driver = { 372 .driver = { 373 .name = "cros-ec-i2c", 374 .acpi_match_table = ACPI_PTR(cros_ec_i2c_acpi_id), 375 .of_match_table = of_match_ptr(cros_ec_i2c_of_match), 376 .pm = &cros_ec_i2c_pm_ops, 377 }, 378 .probe = cros_ec_i2c_probe, 379 .remove = cros_ec_i2c_remove, 380 .id_table = cros_ec_i2c_id, 381 }; 382 383 module_i2c_driver(cros_ec_driver); 384 385 MODULE_LICENSE("GPL"); 386 MODULE_DESCRIPTION("ChromeOS EC multi function device"); 387