1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * at24.c - handle most I2C EEPROMs 4 * 5 * Copyright (C) 2005-2007 David Brownell 6 * Copyright (C) 2008 Wolfram Sang, Pengutronix 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/init.h> 11 #include <linux/module.h> 12 #include <linux/of_device.h> 13 #include <linux/slab.h> 14 #include <linux/delay.h> 15 #include <linux/mutex.h> 16 #include <linux/mod_devicetable.h> 17 #include <linux/log2.h> 18 #include <linux/bitops.h> 19 #include <linux/jiffies.h> 20 #include <linux/property.h> 21 #include <linux/acpi.h> 22 #include <linux/i2c.h> 23 #include <linux/nvmem-provider.h> 24 #include <linux/regmap.h> 25 #include <linux/platform_data/at24.h> 26 #include <linux/pm_runtime.h> 27 #include <linux/gpio/consumer.h> 28 29 /* 30 * I2C EEPROMs from most vendors are inexpensive and mostly interchangeable. 31 * Differences between different vendor product lines (like Atmel AT24C or 32 * MicroChip 24LC, etc) won't much matter for typical read/write access. 33 * There are also I2C RAM chips, likewise interchangeable. One example 34 * would be the PCF8570, which acts like a 24c02 EEPROM (256 bytes). 35 * 36 * However, misconfiguration can lose data. "Set 16-bit memory address" 37 * to a part with 8-bit addressing will overwrite data. Writing with too 38 * big a page size also loses data. And it's not safe to assume that the 39 * conventional addresses 0x50..0x57 only hold eeproms; a PCF8563 RTC 40 * uses 0x51, for just one example. 41 * 42 * Accordingly, explicit board-specific configuration data should be used 43 * in almost all cases. (One partial exception is an SMBus used to access 44 * "SPD" data for DRAM sticks. Those only use 24c02 EEPROMs.) 45 * 46 * So this driver uses "new style" I2C driver binding, expecting to be 47 * told what devices exist. That may be in arch/X/mach-Y/board-Z.c or 48 * similar kernel-resident tables; or, configuration data coming from 49 * a bootloader. 50 * 51 * Other than binding model, current differences from "eeprom" driver are 52 * that this one handles write access and isn't restricted to 24c02 devices. 53 * It also handles larger devices (32 kbit and up) with two-byte addresses, 54 * which won't work on pure SMBus systems. 55 */ 56 57 struct at24_client { 58 struct i2c_client *client; 59 struct regmap *regmap; 60 }; 61 62 struct at24_data { 63 /* 64 * Lock protects against activities from other Linux tasks, 65 * but not from changes by other I2C masters. 66 */ 67 struct mutex lock; 68 69 unsigned int write_max; 70 unsigned int num_addresses; 71 unsigned int offset_adj; 72 73 u32 byte_len; 74 u16 page_size; 75 u8 flags; 76 77 struct nvmem_device *nvmem; 78 79 struct gpio_desc *wp_gpio; 80 81 /* 82 * Some chips tie up multiple I2C addresses; dummy devices reserve 83 * them for us, and we'll use them with SMBus calls. 84 */ 85 struct at24_client client[]; 86 }; 87 88 /* 89 * This parameter is to help this driver avoid blocking other drivers out 90 * of I2C for potentially troublesome amounts of time. With a 100 kHz I2C 91 * clock, one 256 byte read takes about 1/43 second which is excessive; 92 * but the 1/170 second it takes at 400 kHz may be quite reasonable; and 93 * at 1 MHz (Fm+) a 1/430 second delay could easily be invisible. 94 * 95 * This value is forced to be a power of two so that writes align on pages. 96 */ 97 static unsigned int at24_io_limit = 128; 98 module_param_named(io_limit, at24_io_limit, uint, 0); 99 MODULE_PARM_DESC(at24_io_limit, "Maximum bytes per I/O (default 128)"); 100 101 /* 102 * Specs often allow 5 msec for a page write, sometimes 20 msec; 103 * it's important to recover from write timeouts. 104 */ 105 static unsigned int at24_write_timeout = 25; 106 module_param_named(write_timeout, at24_write_timeout, uint, 0); 107 MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)"); 108 109 /* 110 * Both reads and writes fail if the previous write didn't complete yet. This 111 * macro loops a few times waiting at least long enough for one entire page 112 * write to work while making sure that at least one iteration is run before 113 * checking the break condition. 114 * 115 * It takes two parameters: a variable in which the future timeout in jiffies 116 * will be stored and a temporary variable holding the time of the last 117 * iteration of processing the request. Both should be unsigned integers 118 * holding at least 32 bits. 119 */ 120 #define at24_loop_until_timeout(tout, op_time) \ 121 for (tout = jiffies + msecs_to_jiffies(at24_write_timeout), \ 122 op_time = 0; \ 123 op_time ? time_before(op_time, tout) : true; \ 124 usleep_range(1000, 1500), op_time = jiffies) 125 126 struct at24_chip_data { 127 /* 128 * these fields mirror their equivalents in 129 * struct at24_platform_data 130 */ 131 u32 byte_len; 132 u8 flags; 133 }; 134 135 #define AT24_CHIP_DATA(_name, _len, _flags) \ 136 static const struct at24_chip_data _name = { \ 137 .byte_len = _len, .flags = _flags, \ 138 } 139 140 /* needs 8 addresses as A0-A2 are ignored */ 141 AT24_CHIP_DATA(at24_data_24c00, 128 / 8, AT24_FLAG_TAKE8ADDR); 142 /* old variants can't be handled with this generic entry! */ 143 AT24_CHIP_DATA(at24_data_24c01, 1024 / 8, 0); 144 AT24_CHIP_DATA(at24_data_24cs01, 16, 145 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 146 AT24_CHIP_DATA(at24_data_24c02, 2048 / 8, 0); 147 AT24_CHIP_DATA(at24_data_24cs02, 16, 148 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 149 AT24_CHIP_DATA(at24_data_24mac402, 48 / 8, 150 AT24_FLAG_MAC | AT24_FLAG_READONLY); 151 AT24_CHIP_DATA(at24_data_24mac602, 64 / 8, 152 AT24_FLAG_MAC | AT24_FLAG_READONLY); 153 /* spd is a 24c02 in memory DIMMs */ 154 AT24_CHIP_DATA(at24_data_spd, 2048 / 8, 155 AT24_FLAG_READONLY | AT24_FLAG_IRUGO); 156 AT24_CHIP_DATA(at24_data_24c04, 4096 / 8, 0); 157 AT24_CHIP_DATA(at24_data_24cs04, 16, 158 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 159 /* 24rf08 quirk is handled at i2c-core */ 160 AT24_CHIP_DATA(at24_data_24c08, 8192 / 8, 0); 161 AT24_CHIP_DATA(at24_data_24cs08, 16, 162 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 163 AT24_CHIP_DATA(at24_data_24c16, 16384 / 8, 0); 164 AT24_CHIP_DATA(at24_data_24cs16, 16, 165 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 166 AT24_CHIP_DATA(at24_data_24c32, 32768 / 8, AT24_FLAG_ADDR16); 167 AT24_CHIP_DATA(at24_data_24cs32, 16, 168 AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 169 AT24_CHIP_DATA(at24_data_24c64, 65536 / 8, AT24_FLAG_ADDR16); 170 AT24_CHIP_DATA(at24_data_24cs64, 16, 171 AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 172 AT24_CHIP_DATA(at24_data_24c128, 131072 / 8, AT24_FLAG_ADDR16); 173 AT24_CHIP_DATA(at24_data_24c256, 262144 / 8, AT24_FLAG_ADDR16); 174 AT24_CHIP_DATA(at24_data_24c512, 524288 / 8, AT24_FLAG_ADDR16); 175 AT24_CHIP_DATA(at24_data_24c1024, 1048576 / 8, AT24_FLAG_ADDR16); 176 /* identical to 24c08 ? */ 177 AT24_CHIP_DATA(at24_data_INT3499, 8192 / 8, 0); 178 179 static const struct i2c_device_id at24_ids[] = { 180 { "24c00", (kernel_ulong_t)&at24_data_24c00 }, 181 { "24c01", (kernel_ulong_t)&at24_data_24c01 }, 182 { "24cs01", (kernel_ulong_t)&at24_data_24cs01 }, 183 { "24c02", (kernel_ulong_t)&at24_data_24c02 }, 184 { "24cs02", (kernel_ulong_t)&at24_data_24cs02 }, 185 { "24mac402", (kernel_ulong_t)&at24_data_24mac402 }, 186 { "24mac602", (kernel_ulong_t)&at24_data_24mac602 }, 187 { "spd", (kernel_ulong_t)&at24_data_spd }, 188 { "24c04", (kernel_ulong_t)&at24_data_24c04 }, 189 { "24cs04", (kernel_ulong_t)&at24_data_24cs04 }, 190 { "24c08", (kernel_ulong_t)&at24_data_24c08 }, 191 { "24cs08", (kernel_ulong_t)&at24_data_24cs08 }, 192 { "24c16", (kernel_ulong_t)&at24_data_24c16 }, 193 { "24cs16", (kernel_ulong_t)&at24_data_24cs16 }, 194 { "24c32", (kernel_ulong_t)&at24_data_24c32 }, 195 { "24cs32", (kernel_ulong_t)&at24_data_24cs32 }, 196 { "24c64", (kernel_ulong_t)&at24_data_24c64 }, 197 { "24cs64", (kernel_ulong_t)&at24_data_24cs64 }, 198 { "24c128", (kernel_ulong_t)&at24_data_24c128 }, 199 { "24c256", (kernel_ulong_t)&at24_data_24c256 }, 200 { "24c512", (kernel_ulong_t)&at24_data_24c512 }, 201 { "24c1024", (kernel_ulong_t)&at24_data_24c1024 }, 202 { "at24", 0 }, 203 { /* END OF LIST */ } 204 }; 205 MODULE_DEVICE_TABLE(i2c, at24_ids); 206 207 static const struct of_device_id at24_of_match[] = { 208 { .compatible = "atmel,24c00", .data = &at24_data_24c00 }, 209 { .compatible = "atmel,24c01", .data = &at24_data_24c01 }, 210 { .compatible = "atmel,24cs01", .data = &at24_data_24cs01 }, 211 { .compatible = "atmel,24c02", .data = &at24_data_24c02 }, 212 { .compatible = "atmel,24cs02", .data = &at24_data_24cs02 }, 213 { .compatible = "atmel,24mac402", .data = &at24_data_24mac402 }, 214 { .compatible = "atmel,24mac602", .data = &at24_data_24mac602 }, 215 { .compatible = "atmel,spd", .data = &at24_data_spd }, 216 { .compatible = "atmel,24c04", .data = &at24_data_24c04 }, 217 { .compatible = "atmel,24cs04", .data = &at24_data_24cs04 }, 218 { .compatible = "atmel,24c08", .data = &at24_data_24c08 }, 219 { .compatible = "atmel,24cs08", .data = &at24_data_24cs08 }, 220 { .compatible = "atmel,24c16", .data = &at24_data_24c16 }, 221 { .compatible = "atmel,24cs16", .data = &at24_data_24cs16 }, 222 { .compatible = "atmel,24c32", .data = &at24_data_24c32 }, 223 { .compatible = "atmel,24cs32", .data = &at24_data_24cs32 }, 224 { .compatible = "atmel,24c64", .data = &at24_data_24c64 }, 225 { .compatible = "atmel,24cs64", .data = &at24_data_24cs64 }, 226 { .compatible = "atmel,24c128", .data = &at24_data_24c128 }, 227 { .compatible = "atmel,24c256", .data = &at24_data_24c256 }, 228 { .compatible = "atmel,24c512", .data = &at24_data_24c512 }, 229 { .compatible = "atmel,24c1024", .data = &at24_data_24c1024 }, 230 { /* END OF LIST */ }, 231 }; 232 MODULE_DEVICE_TABLE(of, at24_of_match); 233 234 static const struct acpi_device_id at24_acpi_ids[] = { 235 { "INT3499", (kernel_ulong_t)&at24_data_INT3499 }, 236 { /* END OF LIST */ } 237 }; 238 MODULE_DEVICE_TABLE(acpi, at24_acpi_ids); 239 240 /* 241 * This routine supports chips which consume multiple I2C addresses. It 242 * computes the addressing information to be used for a given r/w request. 243 * Assumes that sanity checks for offset happened at sysfs-layer. 244 * 245 * Slave address and byte offset derive from the offset. Always 246 * set the byte address; on a multi-master board, another master 247 * may have changed the chip's "current" address pointer. 248 */ 249 static struct at24_client *at24_translate_offset(struct at24_data *at24, 250 unsigned int *offset) 251 { 252 unsigned int i; 253 254 if (at24->flags & AT24_FLAG_ADDR16) { 255 i = *offset >> 16; 256 *offset &= 0xffff; 257 } else { 258 i = *offset >> 8; 259 *offset &= 0xff; 260 } 261 262 return &at24->client[i]; 263 } 264 265 static struct device *at24_base_client_dev(struct at24_data *at24) 266 { 267 return &at24->client[0].client->dev; 268 } 269 270 static size_t at24_adjust_read_count(struct at24_data *at24, 271 unsigned int offset, size_t count) 272 { 273 unsigned int bits; 274 size_t remainder; 275 276 /* 277 * In case of multi-address chips that don't rollover reads to 278 * the next slave address: truncate the count to the slave boundary, 279 * so that the read never straddles slaves. 280 */ 281 if (at24->flags & AT24_FLAG_NO_RDROL) { 282 bits = (at24->flags & AT24_FLAG_ADDR16) ? 16 : 8; 283 remainder = BIT(bits) - offset; 284 if (count > remainder) 285 count = remainder; 286 } 287 288 if (count > at24_io_limit) 289 count = at24_io_limit; 290 291 return count; 292 } 293 294 static ssize_t at24_regmap_read(struct at24_data *at24, char *buf, 295 unsigned int offset, size_t count) 296 { 297 unsigned long timeout, read_time; 298 struct at24_client *at24_client; 299 struct i2c_client *client; 300 struct regmap *regmap; 301 int ret; 302 303 at24_client = at24_translate_offset(at24, &offset); 304 regmap = at24_client->regmap; 305 client = at24_client->client; 306 count = at24_adjust_read_count(at24, offset, count); 307 308 /* adjust offset for mac and serial read ops */ 309 offset += at24->offset_adj; 310 311 at24_loop_until_timeout(timeout, read_time) { 312 ret = regmap_bulk_read(regmap, offset, buf, count); 313 dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n", 314 count, offset, ret, jiffies); 315 if (!ret) 316 return count; 317 } 318 319 return -ETIMEDOUT; 320 } 321 322 /* 323 * Note that if the hardware write-protect pin is pulled high, the whole 324 * chip is normally write protected. But there are plenty of product 325 * variants here, including OTP fuses and partial chip protect. 326 * 327 * We only use page mode writes; the alternative is sloooow. These routines 328 * write at most one page. 329 */ 330 331 static size_t at24_adjust_write_count(struct at24_data *at24, 332 unsigned int offset, size_t count) 333 { 334 unsigned int next_page; 335 336 /* write_max is at most a page */ 337 if (count > at24->write_max) 338 count = at24->write_max; 339 340 /* Never roll over backwards, to the start of this page */ 341 next_page = roundup(offset + 1, at24->page_size); 342 if (offset + count > next_page) 343 count = next_page - offset; 344 345 return count; 346 } 347 348 static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf, 349 unsigned int offset, size_t count) 350 { 351 unsigned long timeout, write_time; 352 struct at24_client *at24_client; 353 struct i2c_client *client; 354 struct regmap *regmap; 355 int ret; 356 357 at24_client = at24_translate_offset(at24, &offset); 358 regmap = at24_client->regmap; 359 client = at24_client->client; 360 count = at24_adjust_write_count(at24, offset, count); 361 362 at24_loop_until_timeout(timeout, write_time) { 363 ret = regmap_bulk_write(regmap, offset, buf, count); 364 dev_dbg(&client->dev, "write %zu@%d --> %d (%ld)\n", 365 count, offset, ret, jiffies); 366 if (!ret) 367 return count; 368 } 369 370 return -ETIMEDOUT; 371 } 372 373 static int at24_read(void *priv, unsigned int off, void *val, size_t count) 374 { 375 struct at24_data *at24; 376 struct device *dev; 377 char *buf = val; 378 int ret; 379 380 at24 = priv; 381 dev = at24_base_client_dev(at24); 382 383 if (unlikely(!count)) 384 return count; 385 386 if (off + count > at24->byte_len) 387 return -EINVAL; 388 389 ret = pm_runtime_get_sync(dev); 390 if (ret < 0) { 391 pm_runtime_put_noidle(dev); 392 return ret; 393 } 394 395 /* 396 * Read data from chip, protecting against concurrent updates 397 * from this host, but not from other I2C masters. 398 */ 399 mutex_lock(&at24->lock); 400 401 while (count) { 402 ret = at24_regmap_read(at24, buf, off, count); 403 if (ret < 0) { 404 mutex_unlock(&at24->lock); 405 pm_runtime_put(dev); 406 return ret; 407 } 408 buf += ret; 409 off += ret; 410 count -= ret; 411 } 412 413 mutex_unlock(&at24->lock); 414 415 pm_runtime_put(dev); 416 417 return 0; 418 } 419 420 static int at24_write(void *priv, unsigned int off, void *val, size_t count) 421 { 422 struct at24_data *at24; 423 struct device *dev; 424 char *buf = val; 425 int ret; 426 427 at24 = priv; 428 dev = at24_base_client_dev(at24); 429 430 if (unlikely(!count)) 431 return -EINVAL; 432 433 if (off + count > at24->byte_len) 434 return -EINVAL; 435 436 ret = pm_runtime_get_sync(dev); 437 if (ret < 0) { 438 pm_runtime_put_noidle(dev); 439 return ret; 440 } 441 442 /* 443 * Write data to chip, protecting against concurrent updates 444 * from this host, but not from other I2C masters. 445 */ 446 mutex_lock(&at24->lock); 447 gpiod_set_value_cansleep(at24->wp_gpio, 0); 448 449 while (count) { 450 ret = at24_regmap_write(at24, buf, off, count); 451 if (ret < 0) { 452 gpiod_set_value_cansleep(at24->wp_gpio, 1); 453 mutex_unlock(&at24->lock); 454 pm_runtime_put(dev); 455 return ret; 456 } 457 buf += ret; 458 off += ret; 459 count -= ret; 460 } 461 462 gpiod_set_value_cansleep(at24->wp_gpio, 1); 463 mutex_unlock(&at24->lock); 464 465 pm_runtime_put(dev); 466 467 return 0; 468 } 469 470 static void at24_properties_to_pdata(struct device *dev, 471 struct at24_platform_data *chip) 472 { 473 int err; 474 u32 val; 475 476 if (device_property_present(dev, "read-only")) 477 chip->flags |= AT24_FLAG_READONLY; 478 if (device_property_present(dev, "no-read-rollover")) 479 chip->flags |= AT24_FLAG_NO_RDROL; 480 481 err = device_property_read_u32(dev, "size", &val); 482 if (!err) 483 chip->byte_len = val; 484 485 err = device_property_read_u32(dev, "pagesize", &val); 486 if (!err) { 487 chip->page_size = val; 488 } else { 489 /* 490 * This is slow, but we can't know all eeproms, so we better 491 * play safe. Specifying custom eeprom-types via platform_data 492 * is recommended anyhow. 493 */ 494 chip->page_size = 1; 495 } 496 } 497 498 static int at24_get_pdata(struct device *dev, struct at24_platform_data *pdata) 499 { 500 struct device_node *of_node = dev->of_node; 501 const struct at24_chip_data *cdata; 502 const struct i2c_device_id *id; 503 struct at24_platform_data *pd; 504 505 pd = dev_get_platdata(dev); 506 if (pd) { 507 memcpy(pdata, pd, sizeof(*pdata)); 508 return 0; 509 } 510 511 id = i2c_match_id(at24_ids, to_i2c_client(dev)); 512 513 /* 514 * The I2C core allows OF nodes compatibles to match against the 515 * I2C device ID table as a fallback, so check not only if an OF 516 * node is present but also if it matches an OF device ID entry. 517 */ 518 if (of_node && of_match_device(at24_of_match, dev)) 519 cdata = of_device_get_match_data(dev); 520 else if (id) 521 cdata = (void *)&id->driver_data; 522 else 523 cdata = acpi_device_get_match_data(dev); 524 525 if (!cdata) 526 return -ENODEV; 527 528 pdata->byte_len = cdata->byte_len; 529 pdata->flags = cdata->flags; 530 at24_properties_to_pdata(dev, pdata); 531 532 return 0; 533 } 534 535 static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len) 536 { 537 if (flags & AT24_FLAG_MAC) { 538 /* EUI-48 starts from 0x9a, EUI-64 from 0x98 */ 539 return 0xa0 - byte_len; 540 } else if (flags & AT24_FLAG_SERIAL && flags & AT24_FLAG_ADDR16) { 541 /* 542 * For 16 bit address pointers, the word address must contain 543 * a '10' sequence in bits 11 and 10 regardless of the 544 * intended position of the address pointer. 545 */ 546 return 0x0800; 547 } else if (flags & AT24_FLAG_SERIAL) { 548 /* 549 * Otherwise the word address must begin with a '10' sequence, 550 * regardless of the intended address. 551 */ 552 return 0x0080; 553 } else { 554 return 0; 555 } 556 } 557 558 static int at24_probe(struct i2c_client *client) 559 { 560 struct regmap_config regmap_config = { }; 561 struct nvmem_config nvmem_config = { }; 562 struct at24_platform_data pdata = { }; 563 struct device *dev = &client->dev; 564 bool i2c_fn_i2c, i2c_fn_block; 565 unsigned int i, num_addresses; 566 struct at24_data *at24; 567 struct regmap *regmap; 568 size_t at24_size; 569 bool writable; 570 u8 test_byte; 571 int err; 572 573 i2c_fn_i2c = i2c_check_functionality(client->adapter, I2C_FUNC_I2C); 574 i2c_fn_block = i2c_check_functionality(client->adapter, 575 I2C_FUNC_SMBUS_WRITE_I2C_BLOCK); 576 577 err = at24_get_pdata(dev, &pdata); 578 if (err) 579 return err; 580 581 if (!i2c_fn_i2c && !i2c_fn_block) 582 pdata.page_size = 1; 583 584 if (!pdata.page_size) { 585 dev_err(dev, "page_size must not be 0!\n"); 586 return -EINVAL; 587 } 588 589 if (!is_power_of_2(pdata.page_size)) 590 dev_warn(dev, "page_size looks suspicious (no power of 2)!\n"); 591 592 if (pdata.flags & AT24_FLAG_TAKE8ADDR) 593 num_addresses = 8; 594 else 595 num_addresses = DIV_ROUND_UP(pdata.byte_len, 596 (pdata.flags & AT24_FLAG_ADDR16) ? 65536 : 256); 597 598 if ((pdata.flags & AT24_FLAG_SERIAL) && (pdata.flags & AT24_FLAG_MAC)) { 599 dev_err(dev, 600 "invalid device data - cannot have both AT24_FLAG_SERIAL & AT24_FLAG_MAC."); 601 return -EINVAL; 602 } 603 604 regmap_config.val_bits = 8; 605 regmap_config.reg_bits = (pdata.flags & AT24_FLAG_ADDR16) ? 16 : 8; 606 regmap_config.disable_locking = true; 607 608 regmap = devm_regmap_init_i2c(client, ®map_config); 609 if (IS_ERR(regmap)) 610 return PTR_ERR(regmap); 611 612 at24_size = sizeof(*at24) + num_addresses * sizeof(struct at24_client); 613 at24 = devm_kzalloc(dev, at24_size, GFP_KERNEL); 614 if (!at24) 615 return -ENOMEM; 616 617 mutex_init(&at24->lock); 618 at24->byte_len = pdata.byte_len; 619 at24->page_size = pdata.page_size; 620 at24->flags = pdata.flags; 621 at24->num_addresses = num_addresses; 622 at24->offset_adj = at24_get_offset_adj(pdata.flags, pdata.byte_len); 623 at24->client[0].client = client; 624 at24->client[0].regmap = regmap; 625 626 at24->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_HIGH); 627 if (IS_ERR(at24->wp_gpio)) 628 return PTR_ERR(at24->wp_gpio); 629 630 writable = !(pdata.flags & AT24_FLAG_READONLY); 631 if (writable) { 632 at24->write_max = min_t(unsigned int, 633 pdata.page_size, at24_io_limit); 634 if (!i2c_fn_i2c && at24->write_max > I2C_SMBUS_BLOCK_MAX) 635 at24->write_max = I2C_SMBUS_BLOCK_MAX; 636 } 637 638 /* use dummy devices for multiple-address chips */ 639 for (i = 1; i < num_addresses; i++) { 640 at24->client[i].client = i2c_new_dummy(client->adapter, 641 client->addr + i); 642 if (!at24->client[i].client) { 643 dev_err(dev, "address 0x%02x unavailable\n", 644 client->addr + i); 645 err = -EADDRINUSE; 646 goto err_clients; 647 } 648 at24->client[i].regmap = devm_regmap_init_i2c( 649 at24->client[i].client, 650 ®map_config); 651 if (IS_ERR(at24->client[i].regmap)) { 652 err = PTR_ERR(at24->client[i].regmap); 653 goto err_clients; 654 } 655 } 656 657 i2c_set_clientdata(client, at24); 658 659 /* enable runtime pm */ 660 pm_runtime_set_active(dev); 661 pm_runtime_enable(dev); 662 663 /* 664 * Perform a one-byte test read to verify that the 665 * chip is functional. 666 */ 667 err = at24_read(at24, 0, &test_byte, 1); 668 pm_runtime_idle(dev); 669 if (err) { 670 err = -ENODEV; 671 goto err_clients; 672 } 673 674 nvmem_config.name = dev_name(dev); 675 nvmem_config.dev = dev; 676 nvmem_config.read_only = !writable; 677 nvmem_config.root_only = true; 678 nvmem_config.owner = THIS_MODULE; 679 nvmem_config.compat = true; 680 nvmem_config.base_dev = dev; 681 nvmem_config.reg_read = at24_read; 682 nvmem_config.reg_write = at24_write; 683 nvmem_config.priv = at24; 684 nvmem_config.stride = 1; 685 nvmem_config.word_size = 1; 686 nvmem_config.size = pdata.byte_len; 687 688 at24->nvmem = nvmem_register(&nvmem_config); 689 if (IS_ERR(at24->nvmem)) { 690 err = PTR_ERR(at24->nvmem); 691 goto err_clients; 692 } 693 694 dev_info(dev, "%u byte %s EEPROM, %s, %u bytes/write\n", 695 pdata.byte_len, client->name, 696 writable ? "writable" : "read-only", at24->write_max); 697 698 /* export data to kernel code */ 699 if (pdata.setup) 700 pdata.setup(at24->nvmem, pdata.context); 701 702 return 0; 703 704 err_clients: 705 for (i = 1; i < num_addresses; i++) 706 if (at24->client[i].client) 707 i2c_unregister_device(at24->client[i].client); 708 709 pm_runtime_disable(dev); 710 711 return err; 712 } 713 714 static int at24_remove(struct i2c_client *client) 715 { 716 struct at24_data *at24; 717 int i; 718 719 at24 = i2c_get_clientdata(client); 720 721 nvmem_unregister(at24->nvmem); 722 723 for (i = 1; i < at24->num_addresses; i++) 724 i2c_unregister_device(at24->client[i].client); 725 726 pm_runtime_disable(&client->dev); 727 pm_runtime_set_suspended(&client->dev); 728 729 return 0; 730 } 731 732 static struct i2c_driver at24_driver = { 733 .driver = { 734 .name = "at24", 735 .of_match_table = at24_of_match, 736 .acpi_match_table = ACPI_PTR(at24_acpi_ids), 737 }, 738 .probe_new = at24_probe, 739 .remove = at24_remove, 740 .id_table = at24_ids, 741 }; 742 743 static int __init at24_init(void) 744 { 745 if (!at24_io_limit) { 746 pr_err("at24: at24_io_limit must not be 0!\n"); 747 return -EINVAL; 748 } 749 750 at24_io_limit = rounddown_pow_of_two(at24_io_limit); 751 return i2c_add_driver(&at24_driver); 752 } 753 module_init(at24_init); 754 755 static void __exit at24_exit(void) 756 { 757 i2c_del_driver(&at24_driver); 758 } 759 module_exit(at24_exit); 760 761 MODULE_DESCRIPTION("Driver for most I2C EEPROMs"); 762 MODULE_AUTHOR("David Brownell and Wolfram Sang"); 763 MODULE_LICENSE("GPL"); 764