1 /* 2 * Copyright (c) 2014 Google, Inc 3 * 4 * SPDX-License-Identifier: GPL-2.0+ 5 */ 6 7 #include <common.h> 8 #include <dm.h> 9 #include <errno.h> 10 #include <fdtdec.h> 11 #include <i2c.h> 12 #include <malloc.h> 13 #include <dm/device-internal.h> 14 #include <dm/lists.h> 15 16 DECLARE_GLOBAL_DATA_PTR; 17 18 #define I2C_MAX_OFFSET_LEN 4 19 20 /* Useful debugging function */ 21 void i2c_dump_msgs(struct i2c_msg *msg, int nmsgs) 22 { 23 int i; 24 25 for (i = 0; i < nmsgs; i++) { 26 struct i2c_msg *m = &msg[i]; 27 28 printf(" %s %x len=%x", m->flags & I2C_M_RD ? "R" : "W", 29 msg->addr, msg->len); 30 if (!(m->flags & I2C_M_RD)) 31 printf(": %x", m->buf[0]); 32 printf("\n"); 33 } 34 } 35 36 /** 37 * i2c_setup_offset() - Set up a new message with a chip offset 38 * 39 * @chip: Chip to use 40 * @offset: Byte offset within chip 41 * @offset_buf: Place to put byte offset 42 * @msg: Message buffer 43 * @return 0 if OK, -EADDRNOTAVAIL if the offset length is 0. In that case the 44 * message is still set up but will not contain an offset. 45 */ 46 static int i2c_setup_offset(struct dm_i2c_chip *chip, uint offset, 47 uint8_t offset_buf[], struct i2c_msg *msg) 48 { 49 int offset_len; 50 51 msg->addr = chip->chip_addr; 52 msg->flags = chip->flags & DM_I2C_CHIP_10BIT ? I2C_M_TEN : 0; 53 msg->len = chip->offset_len; 54 msg->buf = offset_buf; 55 if (!chip->offset_len) 56 return -EADDRNOTAVAIL; 57 assert(chip->offset_len <= I2C_MAX_OFFSET_LEN); 58 offset_len = chip->offset_len; 59 while (offset_len--) 60 *offset_buf++ = offset >> (8 * offset_len); 61 62 return 0; 63 } 64 65 static int i2c_read_bytewise(struct udevice *dev, uint offset, 66 uint8_t *buffer, int len) 67 { 68 struct dm_i2c_chip *chip = dev_get_parent_platdata(dev); 69 struct udevice *bus = dev_get_parent(dev); 70 struct dm_i2c_ops *ops = i2c_get_ops(bus); 71 struct i2c_msg msg[2], *ptr; 72 uint8_t offset_buf[I2C_MAX_OFFSET_LEN]; 73 int ret; 74 int i; 75 76 for (i = 0; i < len; i++) { 77 if (i2c_setup_offset(chip, offset + i, offset_buf, msg)) 78 return -EINVAL; 79 ptr = msg + 1; 80 ptr->addr = chip->chip_addr; 81 ptr->flags = msg->flags | I2C_M_RD; 82 ptr->len = 1; 83 ptr->buf = &buffer[i]; 84 ptr++; 85 86 ret = ops->xfer(bus, msg, ptr - msg); 87 if (ret) 88 return ret; 89 } 90 91 return 0; 92 } 93 94 static int i2c_write_bytewise(struct udevice *dev, uint offset, 95 const uint8_t *buffer, int len) 96 { 97 struct dm_i2c_chip *chip = dev_get_parent_platdata(dev); 98 struct udevice *bus = dev_get_parent(dev); 99 struct dm_i2c_ops *ops = i2c_get_ops(bus); 100 struct i2c_msg msg[1]; 101 uint8_t buf[I2C_MAX_OFFSET_LEN + 1]; 102 int ret; 103 int i; 104 105 for (i = 0; i < len; i++) { 106 if (i2c_setup_offset(chip, offset + i, buf, msg)) 107 return -EINVAL; 108 buf[msg->len++] = buffer[i]; 109 110 ret = ops->xfer(bus, msg, 1); 111 if (ret) 112 return ret; 113 } 114 115 return 0; 116 } 117 118 int dm_i2c_read(struct udevice *dev, uint offset, uint8_t *buffer, int len) 119 { 120 struct dm_i2c_chip *chip = dev_get_parent_platdata(dev); 121 struct udevice *bus = dev_get_parent(dev); 122 struct dm_i2c_ops *ops = i2c_get_ops(bus); 123 struct i2c_msg msg[2], *ptr; 124 uint8_t offset_buf[I2C_MAX_OFFSET_LEN]; 125 int msg_count; 126 127 if (!ops->xfer) 128 return -ENOSYS; 129 if (chip->flags & DM_I2C_CHIP_RD_ADDRESS) 130 return i2c_read_bytewise(dev, offset, buffer, len); 131 ptr = msg; 132 if (!i2c_setup_offset(chip, offset, offset_buf, ptr)) 133 ptr++; 134 135 if (len) { 136 ptr->addr = chip->chip_addr; 137 ptr->flags = chip->flags & DM_I2C_CHIP_10BIT ? I2C_M_TEN : 0; 138 ptr->flags |= I2C_M_RD; 139 ptr->len = len; 140 ptr->buf = buffer; 141 ptr++; 142 } 143 msg_count = ptr - msg; 144 145 return ops->xfer(bus, msg, msg_count); 146 } 147 148 int dm_i2c_write(struct udevice *dev, uint offset, const uint8_t *buffer, 149 int len) 150 { 151 struct dm_i2c_chip *chip = dev_get_parent_platdata(dev); 152 struct udevice *bus = dev_get_parent(dev); 153 struct dm_i2c_ops *ops = i2c_get_ops(bus); 154 struct i2c_msg msg[1]; 155 156 if (!ops->xfer) 157 return -ENOSYS; 158 159 if (chip->flags & DM_I2C_CHIP_WR_ADDRESS) 160 return i2c_write_bytewise(dev, offset, buffer, len); 161 /* 162 * The simple approach would be to send two messages here: one to 163 * set the offset and one to write the bytes. However some drivers 164 * will not be expecting this, and some chips won't like how the 165 * driver presents this on the I2C bus. 166 * 167 * The API does not support separate offset and data. We could extend 168 * it with a flag indicating that there is data in the next message 169 * that needs to be processed in the same transaction. We could 170 * instead add an additional buffer to each message. For now, handle 171 * this in the uclass since it isn't clear what the impact on drivers 172 * would be with this extra complication. Unfortunately this means 173 * copying the message. 174 * 175 * Use the stack for small messages, malloc() for larger ones. We 176 * need to allow space for the offset (up to 4 bytes) and the message 177 * itself. 178 */ 179 if (len < 64) { 180 uint8_t buf[I2C_MAX_OFFSET_LEN + len]; 181 182 i2c_setup_offset(chip, offset, buf, msg); 183 msg->len += len; 184 memcpy(buf + chip->offset_len, buffer, len); 185 186 return ops->xfer(bus, msg, 1); 187 } else { 188 uint8_t *buf; 189 int ret; 190 191 buf = malloc(I2C_MAX_OFFSET_LEN + len); 192 if (!buf) 193 return -ENOMEM; 194 i2c_setup_offset(chip, offset, buf, msg); 195 msg->len += len; 196 memcpy(buf + chip->offset_len, buffer, len); 197 198 ret = ops->xfer(bus, msg, 1); 199 free(buf); 200 return ret; 201 } 202 } 203 204 int dm_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs) 205 { 206 struct udevice *bus = dev_get_parent(dev); 207 struct dm_i2c_ops *ops = i2c_get_ops(bus); 208 209 if (!ops->xfer) 210 return -ENOSYS; 211 212 return ops->xfer(bus, msg, nmsgs); 213 } 214 215 int dm_i2c_reg_read(struct udevice *dev, uint offset) 216 { 217 uint8_t val; 218 int ret; 219 220 ret = dm_i2c_read(dev, offset, &val, 1); 221 if (ret < 0) 222 return ret; 223 224 return val; 225 } 226 227 int dm_i2c_reg_write(struct udevice *dev, uint offset, uint value) 228 { 229 uint8_t val = value; 230 231 return dm_i2c_write(dev, offset, &val, 1); 232 } 233 234 /** 235 * i2c_probe_chip() - probe for a chip on a bus 236 * 237 * @bus: Bus to probe 238 * @chip_addr: Chip address to probe 239 * @flags: Flags for the chip 240 * @return 0 if found, -ENOSYS if the driver is invalid, -EREMOTEIO if the chip 241 * does not respond to probe 242 */ 243 static int i2c_probe_chip(struct udevice *bus, uint chip_addr, 244 enum dm_i2c_chip_flags chip_flags) 245 { 246 struct dm_i2c_ops *ops = i2c_get_ops(bus); 247 struct i2c_msg msg[1]; 248 int ret; 249 250 if (ops->probe_chip) { 251 ret = ops->probe_chip(bus, chip_addr, chip_flags); 252 if (!ret || ret != -ENOSYS) 253 return ret; 254 } 255 256 if (!ops->xfer) 257 return -ENOSYS; 258 259 /* Probe with a zero-length message */ 260 msg->addr = chip_addr; 261 msg->flags = chip_flags & DM_I2C_CHIP_10BIT ? I2C_M_TEN : 0; 262 msg->len = 0; 263 msg->buf = NULL; 264 265 return ops->xfer(bus, msg, 1); 266 } 267 268 static int i2c_bind_driver(struct udevice *bus, uint chip_addr, uint offset_len, 269 struct udevice **devp) 270 { 271 struct dm_i2c_chip *chip; 272 char name[30], *str; 273 struct udevice *dev; 274 int ret; 275 276 snprintf(name, sizeof(name), "generic_%x", chip_addr); 277 str = strdup(name); 278 if (!str) 279 return -ENOMEM; 280 ret = device_bind_driver(bus, "i2c_generic_chip_drv", str, &dev); 281 debug("%s: device_bind_driver: ret=%d\n", __func__, ret); 282 if (ret) 283 goto err_bind; 284 285 /* Tell the device what we know about it */ 286 chip = dev_get_parent_platdata(dev); 287 chip->chip_addr = chip_addr; 288 chip->offset_len = offset_len; 289 ret = device_probe(dev); 290 debug("%s: device_probe: ret=%d\n", __func__, ret); 291 if (ret) 292 goto err_probe; 293 294 *devp = dev; 295 return 0; 296 297 err_probe: 298 /* 299 * If the device failed to probe, unbind it. There is nothing there 300 * on the bus so we don't want to leave it lying around 301 */ 302 device_unbind(dev); 303 err_bind: 304 free(str); 305 return ret; 306 } 307 308 int i2c_get_chip(struct udevice *bus, uint chip_addr, uint offset_len, 309 struct udevice **devp) 310 { 311 struct udevice *dev; 312 313 debug("%s: Searching bus '%s' for address %02x: ", __func__, 314 bus->name, chip_addr); 315 for (device_find_first_child(bus, &dev); dev; 316 device_find_next_child(&dev)) { 317 struct dm_i2c_chip *chip = dev_get_parent_platdata(dev); 318 int ret; 319 320 if (chip->chip_addr == chip_addr) { 321 ret = device_probe(dev); 322 debug("found, ret=%d\n", ret); 323 if (ret) 324 return ret; 325 *devp = dev; 326 return 0; 327 } 328 } 329 debug("not found\n"); 330 return i2c_bind_driver(bus, chip_addr, offset_len, devp); 331 } 332 333 int i2c_get_chip_for_busnum(int busnum, int chip_addr, uint offset_len, 334 struct udevice **devp) 335 { 336 struct udevice *bus; 337 int ret; 338 339 ret = uclass_get_device_by_seq(UCLASS_I2C, busnum, &bus); 340 if (ret) { 341 debug("Cannot find I2C bus %d\n", busnum); 342 return ret; 343 } 344 ret = i2c_get_chip(bus, chip_addr, offset_len, devp); 345 if (ret) { 346 debug("Cannot find I2C chip %02x on bus %d\n", chip_addr, 347 busnum); 348 return ret; 349 } 350 351 return 0; 352 } 353 354 int dm_i2c_probe(struct udevice *bus, uint chip_addr, uint chip_flags, 355 struct udevice **devp) 356 { 357 int ret; 358 359 *devp = NULL; 360 361 /* First probe that chip */ 362 ret = i2c_probe_chip(bus, chip_addr, chip_flags); 363 debug("%s: bus='%s', address %02x, ret=%d\n", __func__, bus->name, 364 chip_addr, ret); 365 if (ret) 366 return ret; 367 368 /* The chip was found, see if we have a driver, and probe it */ 369 ret = i2c_get_chip(bus, chip_addr, 1, devp); 370 debug("%s: i2c_get_chip: ret=%d\n", __func__, ret); 371 372 return ret; 373 } 374 375 int dm_i2c_set_bus_speed(struct udevice *bus, unsigned int speed) 376 { 377 struct dm_i2c_ops *ops = i2c_get_ops(bus); 378 struct dm_i2c_bus *i2c = dev_get_uclass_priv(bus); 379 int ret; 380 381 /* 382 * If we have a method, call it. If not then the driver probably wants 383 * to deal with speed changes on the next transfer. It can easily read 384 * the current speed from this uclass 385 */ 386 if (ops->set_bus_speed) { 387 ret = ops->set_bus_speed(bus, speed); 388 if (ret) 389 return ret; 390 } 391 i2c->speed_hz = speed; 392 393 return 0; 394 } 395 396 int dm_i2c_get_bus_speed(struct udevice *bus) 397 { 398 struct dm_i2c_ops *ops = i2c_get_ops(bus); 399 struct dm_i2c_bus *i2c = dev_get_uclass_priv(bus); 400 401 if (!ops->get_bus_speed) 402 return i2c->speed_hz; 403 404 return ops->get_bus_speed(bus); 405 } 406 407 int i2c_set_chip_flags(struct udevice *dev, uint flags) 408 { 409 struct udevice *bus = dev->parent; 410 struct dm_i2c_chip *chip = dev_get_parent_platdata(dev); 411 struct dm_i2c_ops *ops = i2c_get_ops(bus); 412 int ret; 413 414 if (ops->set_flags) { 415 ret = ops->set_flags(dev, flags); 416 if (ret) 417 return ret; 418 } 419 chip->flags = flags; 420 421 return 0; 422 } 423 424 int i2c_get_chip_flags(struct udevice *dev, uint *flagsp) 425 { 426 struct dm_i2c_chip *chip = dev_get_parent_platdata(dev); 427 428 *flagsp = chip->flags; 429 430 return 0; 431 } 432 433 int i2c_set_chip_offset_len(struct udevice *dev, uint offset_len) 434 { 435 struct dm_i2c_chip *chip = dev_get_parent_platdata(dev); 436 437 if (offset_len > I2C_MAX_OFFSET_LEN) 438 return -EINVAL; 439 chip->offset_len = offset_len; 440 441 return 0; 442 } 443 444 int i2c_get_chip_offset_len(struct udevice *dev) 445 { 446 struct dm_i2c_chip *chip = dev_get_parent_platdata(dev); 447 448 return chip->offset_len; 449 } 450 451 int i2c_deblock(struct udevice *bus) 452 { 453 struct dm_i2c_ops *ops = i2c_get_ops(bus); 454 455 /* 456 * We could implement a software deblocking here if we could get 457 * access to the GPIOs used by I2C, and switch them to GPIO mode 458 * and then back to I2C. This is somewhat beyond our powers in 459 * driver model at present, so for now just fail. 460 * 461 * See https://patchwork.ozlabs.org/patch/399040/ 462 */ 463 if (!ops->deblock) 464 return -ENOSYS; 465 466 return ops->deblock(bus); 467 } 468 469 #if CONFIG_IS_ENABLED(OF_CONTROL) 470 int i2c_chip_ofdata_to_platdata(const void *blob, int node, 471 struct dm_i2c_chip *chip) 472 { 473 chip->offset_len = fdtdec_get_int(gd->fdt_blob, node, 474 "u-boot,i2c-offset-len", 1); 475 chip->flags = 0; 476 chip->chip_addr = fdtdec_get_int(gd->fdt_blob, node, "reg", -1); 477 if (chip->chip_addr == -1) { 478 debug("%s: I2C Node '%s' has no 'reg' property\n", __func__, 479 fdt_get_name(blob, node, NULL)); 480 return -EINVAL; 481 } 482 483 return 0; 484 } 485 #endif 486 487 static int i2c_post_probe(struct udevice *dev) 488 { 489 #if CONFIG_IS_ENABLED(OF_CONTROL) 490 struct dm_i2c_bus *i2c = dev_get_uclass_priv(dev); 491 492 i2c->speed_hz = fdtdec_get_int(gd->fdt_blob, dev->of_offset, 493 "clock-frequency", 100000); 494 495 return dm_i2c_set_bus_speed(dev, i2c->speed_hz); 496 #else 497 return 0; 498 #endif 499 } 500 501 static int i2c_child_post_bind(struct udevice *dev) 502 { 503 #if CONFIG_IS_ENABLED(OF_CONTROL) 504 struct dm_i2c_chip *plat = dev_get_parent_platdata(dev); 505 506 if (dev->of_offset == -1) 507 return 0; 508 509 return i2c_chip_ofdata_to_platdata(gd->fdt_blob, dev->of_offset, plat); 510 #else 511 return 0; 512 #endif 513 } 514 515 UCLASS_DRIVER(i2c) = { 516 .id = UCLASS_I2C, 517 .name = "i2c", 518 .flags = DM_UC_FLAG_SEQ_ALIAS, 519 #if CONFIG_IS_ENABLED(OF_CONTROL) 520 .post_bind = dm_scan_fdt_dev, 521 #endif 522 .post_probe = i2c_post_probe, 523 .per_device_auto_alloc_size = sizeof(struct dm_i2c_bus), 524 .per_child_platdata_auto_alloc_size = sizeof(struct dm_i2c_chip), 525 .child_post_bind = i2c_child_post_bind, 526 }; 527 528 UCLASS_DRIVER(i2c_generic) = { 529 .id = UCLASS_I2C_GENERIC, 530 .name = "i2c_generic", 531 }; 532 533 U_BOOT_DRIVER(i2c_generic_chip_drv) = { 534 .name = "i2c_generic_chip_drv", 535 .id = UCLASS_I2C_GENERIC, 536 }; 537