drivers/i2c/i2c-uclass.c

   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 #include <dm/root.h>
  16
  17 DECLARE_GLOBAL_DATA_PTR;
  18
  19 #define I2C_MAX_OFFSET_LEN      4
  20
  21 /**
  22  * i2c_setup_offset() - Set up a new message with a chip offset
  23  *
  24  * @chip:       Chip to use
  25  * @offset:     Byte offset within chip
  26  * @offset_buf: Place to put byte offset
  27  * @msg:        Message buffer
  28  * @return 0 if OK, -EADDRNOTAVAIL if the offset length is 0. In that case the
  29  * message is still set up but will not contain an offset.
  30  */
  31 static int i2c_setup_offset(struct dm_i2c_chip *chip, uint offset,
  32                             uint8_t offset_buf[], struct i2c_msg *msg)
  33 {
  34         int offset_len;
  35
  36         msg->addr = chip->chip_addr;
  37         msg->flags = chip->flags & DM_I2C_CHIP_10BIT ? I2C_M_TEN : 0;
  38         msg->len = chip->offset_len;
  39         msg->buf = offset_buf;
  40         if (!chip->offset_len)
  41                 return -EADDRNOTAVAIL;
  42         assert(chip->offset_len <= I2C_MAX_OFFSET_LEN);
  43         offset_len = chip->offset_len;
  44         while (offset_len--)
  45                 *offset_buf++ = offset >> (8 * offset_len);
  46
  47         return 0;
  48 }
  49
  50 static int i2c_read_bytewise(struct udevice *dev, uint offset,
  51                              uint8_t *buffer, int len)
  52 {
  53         struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
  54         struct udevice *bus = dev_get_parent(dev);
  55         struct dm_i2c_ops *ops = i2c_get_ops(bus);
  56         struct i2c_msg msg[2], *ptr;
  57         uint8_t offset_buf[I2C_MAX_OFFSET_LEN];
  58         int ret;
  59         int i;
  60
  61         for (i = 0; i < len; i++) {
  62                 if (i2c_setup_offset(chip, offset + i, offset_buf, msg))
  63                         return -EINVAL;
  64                 ptr = msg + 1;
  65                 ptr->addr = chip->chip_addr;
  66                 ptr->flags = msg->flags | I2C_M_RD;
  67                 ptr->len = 1;
  68                 ptr->buf = &buffer[i];
  69                 ptr++;
  70
  71                 ret = ops->xfer(bus, msg, ptr - msg);
  72                 if (ret)
  73                         return ret;
  74         }
  75
  76         return 0;
  77 }
  78
  79 static int i2c_write_bytewise(struct udevice *dev, uint offset,
  80                              const uint8_t *buffer, int len)
  81 {
  82         struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
  83         struct udevice *bus = dev_get_parent(dev);
  84         struct dm_i2c_ops *ops = i2c_get_ops(bus);
  85         struct i2c_msg msg[1];
  86         uint8_t buf[I2C_MAX_OFFSET_LEN + 1];
  87         int ret;
  88         int i;
  89
  90         for (i = 0; i < len; i++) {
  91                 if (i2c_setup_offset(chip, offset + i, buf, msg))
  92                         return -EINVAL;
  93                 buf[msg->len++] = buffer[i];
  94
  95                 ret = ops->xfer(bus, msg, 1);
  96                 if (ret)
  97                         return ret;
  98         }
  99
 100         return 0;
 101 }
 102
 103 int dm_i2c_read(struct udevice *dev, uint offset, uint8_t *buffer, int len)
 104 {
 105         struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
 106         struct udevice *bus = dev_get_parent(dev);
 107         struct dm_i2c_ops *ops = i2c_get_ops(bus);
 108         struct i2c_msg msg[2], *ptr;
 109         uint8_t offset_buf[I2C_MAX_OFFSET_LEN];
 110         int msg_count;
 111
 112         if (!ops->xfer)
 113                 return -ENOSYS;
 114         if (chip->flags & DM_I2C_CHIP_RD_ADDRESS)
 115                 return i2c_read_bytewise(dev, offset, buffer, len);
 116         ptr = msg;
 117         if (!i2c_setup_offset(chip, offset, offset_buf, ptr))
 118                 ptr++;
 119
 120         if (len) {
 121                 ptr->addr = chip->chip_addr;
 122                 ptr->flags = chip->flags & DM_I2C_CHIP_10BIT ? I2C_M_TEN : 0;
 123                 ptr->flags |= I2C_M_RD;
 124                 ptr->len = len;
 125                 ptr->buf = buffer;
 126                 ptr++;
 127         }
 128         msg_count = ptr - msg;
 129
 130         return ops->xfer(bus, msg, msg_count);
 131 }
 132
 133 int dm_i2c_write(struct udevice *dev, uint offset, const uint8_t *buffer,
 134                  int len)
 135 {
 136         struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
 137         struct udevice *bus = dev_get_parent(dev);
 138         struct dm_i2c_ops *ops = i2c_get_ops(bus);
 139         struct i2c_msg msg[1];
 140
 141         if (!ops->xfer)
 142                 return -ENOSYS;
 143
 144         if (chip->flags & DM_I2C_CHIP_WR_ADDRESS)
 145                 return i2c_write_bytewise(dev, offset, buffer, len);
 146         /*
 147          * The simple approach would be to send two messages here: one to
 148          * set the offset and one to write the bytes. However some drivers
 149          * will not be expecting this, and some chips won't like how the
 150          * driver presents this on the I2C bus.
 151          *
 152          * The API does not support separate offset and data. We could extend
 153          * it with a flag indicating that there is data in the next message
 154          * that needs to be processed in the same transaction. We could
 155          * instead add an additional buffer to each message. For now, handle
 156          * this in the uclass since it isn't clear what the impact on drivers
 157          * would be with this extra complication. Unfortunately this means
 158          * copying the message.
 159          *
 160          * Use the stack for small messages, malloc() for larger ones. We
 161          * need to allow space for the offset (up to 4 bytes) and the message
 162          * itself.
 163          */
 164         if (len < 64) {
 165                 uint8_t buf[I2C_MAX_OFFSET_LEN + len];
 166
 167                 i2c_setup_offset(chip, offset, buf, msg);
 168                 msg->len += len;
 169                 memcpy(buf + chip->offset_len, buffer, len);
 170
 171                 return ops->xfer(bus, msg, 1);
 172         } else {
 173                 uint8_t *buf;
 174                 int ret;
 175
 176                 buf = malloc(I2C_MAX_OFFSET_LEN + len);
 177                 if (!buf)
 178                         return -ENOMEM;
 179                 i2c_setup_offset(chip, offset, buf, msg);
 180                 msg->len += len;
 181                 memcpy(buf + chip->offset_len, buffer, len);
 182
 183                 ret = ops->xfer(bus, msg, 1);
 184                 free(buf);
 185                 return ret;
 186         }
 187 }
 188
 189 /**
 190  * i2c_probe_chip() - probe for a chip on a bus
 191  *
 192  * @bus:        Bus to probe
 193  * @chip_addr:  Chip address to probe
 194  * @flags:      Flags for the chip
 195  * @return 0 if found, -ENOSYS if the driver is invalid, -EREMOTEIO if the chip
 196  * does not respond to probe
 197  */
 198 static int i2c_probe_chip(struct udevice *bus, uint chip_addr,
 199                           enum dm_i2c_chip_flags chip_flags)
 200 {
 201         struct dm_i2c_ops *ops = i2c_get_ops(bus);
 202         struct i2c_msg msg[1];
 203         int ret;
 204
 205         if (ops->probe_chip) {
 206                 ret = ops->probe_chip(bus, chip_addr, chip_flags);
 207                 if (!ret || ret != -ENOSYS)
 208                         return ret;
 209         }
 210
 211         if (!ops->xfer)
 212                 return -ENOSYS;
 213
 214         /* Probe with a zero-length message */
 215         msg->addr = chip_addr;
 216         msg->flags = chip_flags & DM_I2C_CHIP_10BIT ? I2C_M_TEN : 0;
 217         msg->len = 0;
 218         msg->buf = NULL;
 219
 220         return ops->xfer(bus, msg, 1);
 221 }
 222
 223 static int i2c_bind_driver(struct udevice *bus, uint chip_addr, uint offset_len,
 224                            struct udevice **devp)
 225 {
 226         struct dm_i2c_chip *chip;
 227         char name[30], *str;
 228         struct udevice *dev;
 229         int ret;
 230
 231         snprintf(name, sizeof(name), "generic_%x", chip_addr);
 232         str = strdup(name);
 233         ret = device_bind_driver(bus, "i2c_generic_chip_drv", str, &dev);
 234         debug("%s:  device_bind_driver: ret=%d\n", __func__, ret);
 235         if (ret)
 236                 goto err_bind;
 237
 238         /* Tell the device what we know about it */
 239         chip = dev_get_parent_platdata(dev);
 240         chip->chip_addr = chip_addr;
 241         chip->offset_len = offset_len;
 242         ret = device_probe(dev);
 243         debug("%s:  device_probe: ret=%d\n", __func__, ret);
 244         if (ret)
 245                 goto err_probe;
 246
 247         *devp = dev;
 248         return 0;
 249
 250 err_probe:
 251         /*
 252          * If the device failed to probe, unbind it. There is nothing there
 253          * on the bus so we don't want to leave it lying around
 254          */
 255         device_unbind(dev);
 256 err_bind:
 257         free(str);
 258         return ret;
 259 }
 260
 261 int i2c_get_chip(struct udevice *bus, uint chip_addr, uint offset_len,
 262                  struct udevice **devp)
 263 {
 264         struct udevice *dev;
 265
 266         debug("%s: Searching bus '%s' for address %02x: ", __func__,
 267               bus->name, chip_addr);
 268         for (device_find_first_child(bus, &dev); dev;
 269                         device_find_next_child(&dev)) {
 270                 struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
 271                 int ret;
 272
 273                 if (chip->chip_addr == chip_addr) {
 274                         ret = device_probe(dev);
 275                         debug("found, ret=%d\n", ret);
 276                         if (ret)
 277                                 return ret;
 278                         *devp = dev;
 279                         return 0;
 280                 }
 281         }
 282         debug("not found\n");
 283         return i2c_bind_driver(bus, chip_addr, offset_len, devp);
 284 }
 285
 286 int i2c_get_chip_for_busnum(int busnum, int chip_addr, uint offset_len,
 287                             struct udevice **devp)
 288 {
 289         struct udevice *bus;
 290         int ret;
 291
 292         ret = uclass_get_device_by_seq(UCLASS_I2C, busnum, &bus);
 293         if (ret) {
 294                 debug("Cannot find I2C bus %d\n", busnum);
 295                 return ret;
 296         }
 297         ret = i2c_get_chip(bus, chip_addr, offset_len, devp);
 298         if (ret) {
 299                 debug("Cannot find I2C chip %02x on bus %d\n", chip_addr,
 300                       busnum);
 301                 return ret;
 302         }
 303
 304         return 0;
 305 }
 306
 307 int dm_i2c_probe(struct udevice *bus, uint chip_addr, uint chip_flags,
 308                  struct udevice **devp)
 309 {
 310         int ret;
 311
 312         *devp = NULL;
 313
 314         /* First probe that chip */
 315         ret = i2c_probe_chip(bus, chip_addr, chip_flags);
 316         debug("%s: bus='%s', address %02x, ret=%d\n", __func__, bus->name,
 317               chip_addr, ret);
 318         if (ret)
 319                 return ret;
 320
 321         /* The chip was found, see if we have a driver, and probe it */
 322         ret = i2c_get_chip(bus, chip_addr, 1, devp);
 323         debug("%s:  i2c_get_chip: ret=%d\n", __func__, ret);
 324
 325         return ret;
 326 }
 327
 328 int i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
 329 {
 330         struct dm_i2c_ops *ops = i2c_get_ops(bus);
 331         struct dm_i2c_bus *i2c = bus->uclass_priv;
 332         int ret;
 333
 334         /*
 335          * If we have a method, call it. If not then the driver probably wants
 336          * to deal with speed changes on the next transfer. It can easily read
 337          * the current speed from this uclass
 338          */
 339         if (ops->set_bus_speed) {
 340                 ret = ops->set_bus_speed(bus, speed);
 341                 if (ret)
 342                         return ret;
 343         }
 344         i2c->speed_hz = speed;
 345
 346         return 0;
 347 }
 348
 349 /*
 350  * i2c_get_bus_speed:
 351  *
 352  *  Returns speed of selected I2C bus in Hz
 353  */
 354 int i2c_get_bus_speed(struct udevice *bus)
 355 {
 356         struct dm_i2c_ops *ops = i2c_get_ops(bus);
 357         struct dm_i2c_bus *i2c = bus->uclass_priv;
 358
 359         if (!ops->get_bus_speed)
 360                 return i2c->speed_hz;
 361
 362         return ops->get_bus_speed(bus);
 363 }
 364
 365 int i2c_set_chip_flags(struct udevice *dev, uint flags)
 366 {
 367         struct udevice *bus = dev->parent;
 368         struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
 369         struct dm_i2c_ops *ops = i2c_get_ops(bus);
 370         int ret;
 371
 372         if (ops->set_flags) {
 373                 ret = ops->set_flags(dev, flags);
 374                 if (ret)
 375                         return ret;
 376         }
 377         chip->flags = flags;
 378
 379         return 0;
 380 }
 381
 382 int i2c_get_chip_flags(struct udevice *dev, uint *flagsp)
 383 {
 384         struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
 385
 386         *flagsp = chip->flags;
 387
 388         return 0;
 389 }
 390
 391 int i2c_set_chip_offset_len(struct udevice *dev, uint offset_len)
 392 {
 393         struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
 394
 395         if (offset_len > I2C_MAX_OFFSET_LEN)
 396                 return -EINVAL;
 397         chip->offset_len = offset_len;
 398
 399         return 0;
 400 }
 401
 402 int i2c_deblock(struct udevice *bus)
 403 {
 404         struct dm_i2c_ops *ops = i2c_get_ops(bus);
 405
 406         /*
 407          * We could implement a software deblocking here if we could get
 408          * access to the GPIOs used by I2C, and switch them to GPIO mode
 409          * and then back to I2C. This is somewhat beyond our powers in
 410          * driver model at present, so for now just fail.
 411          *
 412          * See https://patchwork.ozlabs.org/patch/399040/
 413          */
 414         if (!ops->deblock)
 415                 return -ENOSYS;
 416
 417         return ops->deblock(bus);
 418 }
 419
 420 int i2c_chip_ofdata_to_platdata(const void *blob, int node,
 421                                 struct dm_i2c_chip *chip)
 422 {
 423         chip->offset_len = fdtdec_get_int(gd->fdt_blob, node,
 424                                           "u-boot,i2c-offset-len", 1);
 425         chip->flags = 0;
 426         chip->chip_addr = fdtdec_get_int(gd->fdt_blob, node, "reg", -1);
 427         if (chip->chip_addr == -1) {
 428                 debug("%s: I2C Node '%s' has no 'reg' property\n", __func__,
 429                       fdt_get_name(blob, node, NULL));
 430                 return -EINVAL;
 431         }
 432
 433         return 0;
 434 }
 435
 436 static int i2c_post_probe(struct udevice *dev)
 437 {
 438         struct dm_i2c_bus *i2c = dev->uclass_priv;
 439
 440         i2c->speed_hz = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
 441                                      "clock-frequency", 100000);
 442
 443         return i2c_set_bus_speed(dev, i2c->speed_hz);
 444 }
 445
 446 static int i2c_post_bind(struct udevice *dev)
 447 {
 448         /* Scan the bus for devices */
 449         return dm_scan_fdt_node(dev, gd->fdt_blob, dev->of_offset, false);
 450 }
 451
 452 static int i2c_child_post_bind(struct udevice *dev)
 453 {
 454         struct dm_i2c_chip *plat = dev_get_parent_platdata(dev);
 455
 456         if (dev->of_offset == -1)
 457                 return 0;
 458
 459         return i2c_chip_ofdata_to_platdata(gd->fdt_blob, dev->of_offset, plat);
 460 }
 461
 462 UCLASS_DRIVER(i2c) = {
 463         .id             = UCLASS_I2C,
 464         .name           = "i2c",
 465         .flags          = DM_UC_FLAG_SEQ_ALIAS,
 466         .post_bind      = i2c_post_bind,
 467         .post_probe     = i2c_post_probe,
 468         .per_device_auto_alloc_size = sizeof(struct dm_i2c_bus),
 469         .per_child_platdata_auto_alloc_size = sizeof(struct dm_i2c_chip),
 470         .child_post_bind = i2c_child_post_bind,
 471 };
 472
 473 UCLASS_DRIVER(i2c_generic) = {
 474         .id             = UCLASS_I2C_GENERIC,
 475         .name           = "i2c_generic",
 476 };
 477
 478 U_BOOT_DRIVER(i2c_generic_chip_drv) = {
 479         .name           = "i2c_generic_chip_drv",
 480         .id             = UCLASS_I2C_GENERIC,
 481 };