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 struct at24_chip_data { 110 /* 111 * these fields mirror their equivalents in 112 * struct at24_platform_data 113 */ 114 u32 byte_len; 115 u8 flags; 116 }; 117 118 #define AT24_CHIP_DATA(_name, _len, _flags) \ 119 static const struct at24_chip_data _name = { \ 120 .byte_len = _len, .flags = _flags, \ 121 } 122 123 /* needs 8 addresses as A0-A2 are ignored */ 124 AT24_CHIP_DATA(at24_data_24c00, 128 / 8, AT24_FLAG_TAKE8ADDR); 125 /* old variants can't be handled with this generic entry! */ 126 AT24_CHIP_DATA(at24_data_24c01, 1024 / 8, 0); 127 AT24_CHIP_DATA(at24_data_24cs01, 16, 128 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 129 AT24_CHIP_DATA(at24_data_24c02, 2048 / 8, 0); 130 AT24_CHIP_DATA(at24_data_24cs02, 16, 131 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 132 AT24_CHIP_DATA(at24_data_24mac402, 48 / 8, 133 AT24_FLAG_MAC | AT24_FLAG_READONLY); 134 AT24_CHIP_DATA(at24_data_24mac602, 64 / 8, 135 AT24_FLAG_MAC | AT24_FLAG_READONLY); 136 /* spd is a 24c02 in memory DIMMs */ 137 AT24_CHIP_DATA(at24_data_spd, 2048 / 8, 138 AT24_FLAG_READONLY | AT24_FLAG_IRUGO); 139 AT24_CHIP_DATA(at24_data_24c04, 4096 / 8, 0); 140 AT24_CHIP_DATA(at24_data_24cs04, 16, 141 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 142 /* 24rf08 quirk is handled at i2c-core */ 143 AT24_CHIP_DATA(at24_data_24c08, 8192 / 8, 0); 144 AT24_CHIP_DATA(at24_data_24cs08, 16, 145 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 146 AT24_CHIP_DATA(at24_data_24c16, 16384 / 8, 0); 147 AT24_CHIP_DATA(at24_data_24cs16, 16, 148 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 149 AT24_CHIP_DATA(at24_data_24c32, 32768 / 8, AT24_FLAG_ADDR16); 150 AT24_CHIP_DATA(at24_data_24cs32, 16, 151 AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 152 AT24_CHIP_DATA(at24_data_24c64, 65536 / 8, AT24_FLAG_ADDR16); 153 AT24_CHIP_DATA(at24_data_24cs64, 16, 154 AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 155 AT24_CHIP_DATA(at24_data_24c128, 131072 / 8, AT24_FLAG_ADDR16); 156 AT24_CHIP_DATA(at24_data_24c256, 262144 / 8, AT24_FLAG_ADDR16); 157 AT24_CHIP_DATA(at24_data_24c512, 524288 / 8, AT24_FLAG_ADDR16); 158 AT24_CHIP_DATA(at24_data_24c1024, 1048576 / 8, AT24_FLAG_ADDR16); 159 AT24_CHIP_DATA(at24_data_24c2048, 2097152 / 8, AT24_FLAG_ADDR16); 160 /* identical to 24c08 ? */ 161 AT24_CHIP_DATA(at24_data_INT3499, 8192 / 8, 0); 162 163 static const struct i2c_device_id at24_ids[] = { 164 { "24c00", (kernel_ulong_t)&at24_data_24c00 }, 165 { "24c01", (kernel_ulong_t)&at24_data_24c01 }, 166 { "24cs01", (kernel_ulong_t)&at24_data_24cs01 }, 167 { "24c02", (kernel_ulong_t)&at24_data_24c02 }, 168 { "24cs02", (kernel_ulong_t)&at24_data_24cs02 }, 169 { "24mac402", (kernel_ulong_t)&at24_data_24mac402 }, 170 { "24mac602", (kernel_ulong_t)&at24_data_24mac602 }, 171 { "spd", (kernel_ulong_t)&at24_data_spd }, 172 { "24c04", (kernel_ulong_t)&at24_data_24c04 }, 173 { "24cs04", (kernel_ulong_t)&at24_data_24cs04 }, 174 { "24c08", (kernel_ulong_t)&at24_data_24c08 }, 175 { "24cs08", (kernel_ulong_t)&at24_data_24cs08 }, 176 { "24c16", (kernel_ulong_t)&at24_data_24c16 }, 177 { "24cs16", (kernel_ulong_t)&at24_data_24cs16 }, 178 { "24c32", (kernel_ulong_t)&at24_data_24c32 }, 179 { "24cs32", (kernel_ulong_t)&at24_data_24cs32 }, 180 { "24c64", (kernel_ulong_t)&at24_data_24c64 }, 181 { "24cs64", (kernel_ulong_t)&at24_data_24cs64 }, 182 { "24c128", (kernel_ulong_t)&at24_data_24c128 }, 183 { "24c256", (kernel_ulong_t)&at24_data_24c256 }, 184 { "24c512", (kernel_ulong_t)&at24_data_24c512 }, 185 { "24c1024", (kernel_ulong_t)&at24_data_24c1024 }, 186 { "24c2048", (kernel_ulong_t)&at24_data_24c2048 }, 187 { "at24", 0 }, 188 { /* END OF LIST */ } 189 }; 190 MODULE_DEVICE_TABLE(i2c, at24_ids); 191 192 static const struct of_device_id at24_of_match[] = { 193 { .compatible = "atmel,24c00", .data = &at24_data_24c00 }, 194 { .compatible = "atmel,24c01", .data = &at24_data_24c01 }, 195 { .compatible = "atmel,24cs01", .data = &at24_data_24cs01 }, 196 { .compatible = "atmel,24c02", .data = &at24_data_24c02 }, 197 { .compatible = "atmel,24cs02", .data = &at24_data_24cs02 }, 198 { .compatible = "atmel,24mac402", .data = &at24_data_24mac402 }, 199 { .compatible = "atmel,24mac602", .data = &at24_data_24mac602 }, 200 { .compatible = "atmel,spd", .data = &at24_data_spd }, 201 { .compatible = "atmel,24c04", .data = &at24_data_24c04 }, 202 { .compatible = "atmel,24cs04", .data = &at24_data_24cs04 }, 203 { .compatible = "atmel,24c08", .data = &at24_data_24c08 }, 204 { .compatible = "atmel,24cs08", .data = &at24_data_24cs08 }, 205 { .compatible = "atmel,24c16", .data = &at24_data_24c16 }, 206 { .compatible = "atmel,24cs16", .data = &at24_data_24cs16 }, 207 { .compatible = "atmel,24c32", .data = &at24_data_24c32 }, 208 { .compatible = "atmel,24cs32", .data = &at24_data_24cs32 }, 209 { .compatible = "atmel,24c64", .data = &at24_data_24c64 }, 210 { .compatible = "atmel,24cs64", .data = &at24_data_24cs64 }, 211 { .compatible = "atmel,24c128", .data = &at24_data_24c128 }, 212 { .compatible = "atmel,24c256", .data = &at24_data_24c256 }, 213 { .compatible = "atmel,24c512", .data = &at24_data_24c512 }, 214 { .compatible = "atmel,24c1024", .data = &at24_data_24c1024 }, 215 { .compatible = "atmel,24c2048", .data = &at24_data_24c2048 }, 216 { /* END OF LIST */ }, 217 }; 218 MODULE_DEVICE_TABLE(of, at24_of_match); 219 220 static const struct acpi_device_id at24_acpi_ids[] = { 221 { "INT3499", (kernel_ulong_t)&at24_data_INT3499 }, 222 { /* END OF LIST */ } 223 }; 224 MODULE_DEVICE_TABLE(acpi, at24_acpi_ids); 225 226 /* 227 * This routine supports chips which consume multiple I2C addresses. It 228 * computes the addressing information to be used for a given r/w request. 229 * Assumes that sanity checks for offset happened at sysfs-layer. 230 * 231 * Slave address and byte offset derive from the offset. Always 232 * set the byte address; on a multi-master board, another master 233 * may have changed the chip's "current" address pointer. 234 */ 235 static struct at24_client *at24_translate_offset(struct at24_data *at24, 236 unsigned int *offset) 237 { 238 unsigned int i; 239 240 if (at24->flags & AT24_FLAG_ADDR16) { 241 i = *offset >> 16; 242 *offset &= 0xffff; 243 } else { 244 i = *offset >> 8; 245 *offset &= 0xff; 246 } 247 248 return &at24->client[i]; 249 } 250 251 static struct device *at24_base_client_dev(struct at24_data *at24) 252 { 253 return &at24->client[0].client->dev; 254 } 255 256 static size_t at24_adjust_read_count(struct at24_data *at24, 257 unsigned int offset, size_t count) 258 { 259 unsigned int bits; 260 size_t remainder; 261 262 /* 263 * In case of multi-address chips that don't rollover reads to 264 * the next slave address: truncate the count to the slave boundary, 265 * so that the read never straddles slaves. 266 */ 267 if (at24->flags & AT24_FLAG_NO_RDROL) { 268 bits = (at24->flags & AT24_FLAG_ADDR16) ? 16 : 8; 269 remainder = BIT(bits) - offset; 270 if (count > remainder) 271 count = remainder; 272 } 273 274 if (count > at24_io_limit) 275 count = at24_io_limit; 276 277 return count; 278 } 279 280 static ssize_t at24_regmap_read(struct at24_data *at24, char *buf, 281 unsigned int offset, size_t count) 282 { 283 unsigned long timeout, read_time; 284 struct at24_client *at24_client; 285 struct i2c_client *client; 286 struct regmap *regmap; 287 int ret; 288 289 at24_client = at24_translate_offset(at24, &offset); 290 regmap = at24_client->regmap; 291 client = at24_client->client; 292 count = at24_adjust_read_count(at24, offset, count); 293 294 /* adjust offset for mac and serial read ops */ 295 offset += at24->offset_adj; 296 297 timeout = jiffies + msecs_to_jiffies(at24_write_timeout); 298 do { 299 /* 300 * The timestamp shall be taken before the actual operation 301 * to avoid a premature timeout in case of high CPU load. 302 */ 303 read_time = jiffies; 304 305 ret = regmap_bulk_read(regmap, offset, buf, count); 306 dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n", 307 count, offset, ret, jiffies); 308 if (!ret) 309 return count; 310 311 usleep_range(1000, 1500); 312 } while (time_before(read_time, timeout)); 313 314 return -ETIMEDOUT; 315 } 316 317 /* 318 * Note that if the hardware write-protect pin is pulled high, the whole 319 * chip is normally write protected. But there are plenty of product 320 * variants here, including OTP fuses and partial chip protect. 321 * 322 * We only use page mode writes; the alternative is sloooow. These routines 323 * write at most one page. 324 */ 325 326 static size_t at24_adjust_write_count(struct at24_data *at24, 327 unsigned int offset, size_t count) 328 { 329 unsigned int next_page; 330 331 /* write_max is at most a page */ 332 if (count > at24->write_max) 333 count = at24->write_max; 334 335 /* Never roll over backwards, to the start of this page */ 336 next_page = roundup(offset + 1, at24->page_size); 337 if (offset + count > next_page) 338 count = next_page - offset; 339 340 return count; 341 } 342 343 static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf, 344 unsigned int offset, size_t count) 345 { 346 unsigned long timeout, write_time; 347 struct at24_client *at24_client; 348 struct i2c_client *client; 349 struct regmap *regmap; 350 int ret; 351 352 at24_client = at24_translate_offset(at24, &offset); 353 regmap = at24_client->regmap; 354 client = at24_client->client; 355 count = at24_adjust_write_count(at24, offset, count); 356 timeout = jiffies + msecs_to_jiffies(at24_write_timeout); 357 358 do { 359 /* 360 * The timestamp shall be taken before the actual operation 361 * to avoid a premature timeout in case of high CPU load. 362 */ 363 write_time = jiffies; 364 365 ret = regmap_bulk_write(regmap, offset, buf, count); 366 dev_dbg(&client->dev, "write %zu@%d --> %d (%ld)\n", 367 count, offset, ret, jiffies); 368 if (!ret) 369 return count; 370 371 usleep_range(1000, 1500); 372 } while (time_before(write_time, timeout)); 373 374 return -ETIMEDOUT; 375 } 376 377 static int at24_read(void *priv, unsigned int off, void *val, size_t count) 378 { 379 struct at24_data *at24; 380 struct device *dev; 381 char *buf = val; 382 int ret; 383 384 at24 = priv; 385 dev = at24_base_client_dev(at24); 386 387 if (unlikely(!count)) 388 return count; 389 390 if (off + count > at24->byte_len) 391 return -EINVAL; 392 393 ret = pm_runtime_get_sync(dev); 394 if (ret < 0) { 395 pm_runtime_put_noidle(dev); 396 return ret; 397 } 398 399 /* 400 * Read data from chip, protecting against concurrent updates 401 * from this host, but not from other I2C masters. 402 */ 403 mutex_lock(&at24->lock); 404 405 while (count) { 406 ret = at24_regmap_read(at24, buf, off, count); 407 if (ret < 0) { 408 mutex_unlock(&at24->lock); 409 pm_runtime_put(dev); 410 return ret; 411 } 412 buf += ret; 413 off += ret; 414 count -= ret; 415 } 416 417 mutex_unlock(&at24->lock); 418 419 pm_runtime_put(dev); 420 421 return 0; 422 } 423 424 static int at24_write(void *priv, unsigned int off, void *val, size_t count) 425 { 426 struct at24_data *at24; 427 struct device *dev; 428 char *buf = val; 429 int ret; 430 431 at24 = priv; 432 dev = at24_base_client_dev(at24); 433 434 if (unlikely(!count)) 435 return -EINVAL; 436 437 if (off + count > at24->byte_len) 438 return -EINVAL; 439 440 ret = pm_runtime_get_sync(dev); 441 if (ret < 0) { 442 pm_runtime_put_noidle(dev); 443 return ret; 444 } 445 446 /* 447 * Write data to chip, protecting against concurrent updates 448 * from this host, but not from other I2C masters. 449 */ 450 mutex_lock(&at24->lock); 451 gpiod_set_value_cansleep(at24->wp_gpio, 0); 452 453 while (count) { 454 ret = at24_regmap_write(at24, buf, off, count); 455 if (ret < 0) { 456 gpiod_set_value_cansleep(at24->wp_gpio, 1); 457 mutex_unlock(&at24->lock); 458 pm_runtime_put(dev); 459 return ret; 460 } 461 buf += ret; 462 off += ret; 463 count -= ret; 464 } 465 466 gpiod_set_value_cansleep(at24->wp_gpio, 1); 467 mutex_unlock(&at24->lock); 468 469 pm_runtime_put(dev); 470 471 return 0; 472 } 473 474 static void at24_properties_to_pdata(struct device *dev, 475 struct at24_platform_data *chip) 476 { 477 int err; 478 u32 val; 479 480 if (device_property_present(dev, "read-only")) 481 chip->flags |= AT24_FLAG_READONLY; 482 if (device_property_present(dev, "no-read-rollover")) 483 chip->flags |= AT24_FLAG_NO_RDROL; 484 485 err = device_property_read_u32(dev, "address-width", &val); 486 if (!err) { 487 switch (val) { 488 case 8: 489 if (chip->flags & AT24_FLAG_ADDR16) 490 dev_warn(dev, "Override address width to be 8, while default is 16\n"); 491 chip->flags &= ~AT24_FLAG_ADDR16; 492 break; 493 case 16: 494 chip->flags |= AT24_FLAG_ADDR16; 495 break; 496 default: 497 dev_warn(dev, "Bad \"address-width\" property: %u\n", 498 val); 499 } 500 } 501 502 err = device_property_read_u32(dev, "size", &val); 503 if (!err) 504 chip->byte_len = val; 505 506 err = device_property_read_u32(dev, "pagesize", &val); 507 if (!err) { 508 chip->page_size = val; 509 } else { 510 /* 511 * This is slow, but we can't know all eeproms, so we better 512 * play safe. Specifying custom eeprom-types via platform_data 513 * is recommended anyhow. 514 */ 515 chip->page_size = 1; 516 } 517 } 518 519 static int at24_get_pdata(struct device *dev, struct at24_platform_data *pdata) 520 { 521 struct device_node *of_node = dev->of_node; 522 const struct at24_chip_data *cdata; 523 const struct i2c_device_id *id; 524 struct at24_platform_data *pd; 525 526 pd = dev_get_platdata(dev); 527 if (pd) { 528 memcpy(pdata, pd, sizeof(*pdata)); 529 return 0; 530 } 531 532 id = i2c_match_id(at24_ids, to_i2c_client(dev)); 533 534 /* 535 * The I2C core allows OF nodes compatibles to match against the 536 * I2C device ID table as a fallback, so check not only if an OF 537 * node is present but also if it matches an OF device ID entry. 538 */ 539 if (of_node && of_match_device(at24_of_match, dev)) 540 cdata = of_device_get_match_data(dev); 541 else if (id) 542 cdata = (void *)id->driver_data; 543 else 544 cdata = acpi_device_get_match_data(dev); 545 546 if (!cdata) 547 return -ENODEV; 548 549 pdata->byte_len = cdata->byte_len; 550 pdata->flags = cdata->flags; 551 at24_properties_to_pdata(dev, pdata); 552 553 return 0; 554 } 555 556 static void at24_remove_dummy_clients(struct at24_data *at24) 557 { 558 int i; 559 560 for (i = 1; i < at24->num_addresses; i++) 561 i2c_unregister_device(at24->client[i].client); 562 } 563 564 static int at24_make_dummy_client(struct at24_data *at24, unsigned int index, 565 struct regmap_config *regmap_config) 566 { 567 struct i2c_client *base_client, *dummy_client; 568 unsigned short int addr; 569 struct regmap *regmap; 570 struct device *dev; 571 572 base_client = at24->client[0].client; 573 dev = &base_client->dev; 574 addr = base_client->addr + index; 575 576 dummy_client = i2c_new_dummy(base_client->adapter, 577 base_client->addr + index); 578 if (!dummy_client) { 579 dev_err(dev, "address 0x%02x unavailable\n", addr); 580 return -EADDRINUSE; 581 } 582 583 regmap = devm_regmap_init_i2c(dummy_client, regmap_config); 584 if (IS_ERR(regmap)) { 585 i2c_unregister_device(dummy_client); 586 return PTR_ERR(regmap); 587 } 588 589 at24->client[index].client = dummy_client; 590 at24->client[index].regmap = regmap; 591 592 return 0; 593 } 594 595 static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len) 596 { 597 if (flags & AT24_FLAG_MAC) { 598 /* EUI-48 starts from 0x9a, EUI-64 from 0x98 */ 599 return 0xa0 - byte_len; 600 } else if (flags & AT24_FLAG_SERIAL && flags & AT24_FLAG_ADDR16) { 601 /* 602 * For 16 bit address pointers, the word address must contain 603 * a '10' sequence in bits 11 and 10 regardless of the 604 * intended position of the address pointer. 605 */ 606 return 0x0800; 607 } else if (flags & AT24_FLAG_SERIAL) { 608 /* 609 * Otherwise the word address must begin with a '10' sequence, 610 * regardless of the intended address. 611 */ 612 return 0x0080; 613 } else { 614 return 0; 615 } 616 } 617 618 static int at24_probe(struct i2c_client *client) 619 { 620 struct regmap_config regmap_config = { }; 621 struct nvmem_config nvmem_config = { }; 622 struct at24_platform_data pdata = { }; 623 struct device *dev = &client->dev; 624 bool i2c_fn_i2c, i2c_fn_block; 625 unsigned int i, num_addresses; 626 struct at24_data *at24; 627 struct regmap *regmap; 628 size_t at24_size; 629 bool writable; 630 u8 test_byte; 631 int err; 632 633 i2c_fn_i2c = i2c_check_functionality(client->adapter, I2C_FUNC_I2C); 634 i2c_fn_block = i2c_check_functionality(client->adapter, 635 I2C_FUNC_SMBUS_WRITE_I2C_BLOCK); 636 637 err = at24_get_pdata(dev, &pdata); 638 if (err) 639 return err; 640 641 if (!i2c_fn_i2c && !i2c_fn_block) 642 pdata.page_size = 1; 643 644 if (!pdata.page_size) { 645 dev_err(dev, "page_size must not be 0!\n"); 646 return -EINVAL; 647 } 648 649 if (!is_power_of_2(pdata.page_size)) 650 dev_warn(dev, "page_size looks suspicious (no power of 2)!\n"); 651 652 if (pdata.flags & AT24_FLAG_TAKE8ADDR) 653 num_addresses = 8; 654 else 655 num_addresses = DIV_ROUND_UP(pdata.byte_len, 656 (pdata.flags & AT24_FLAG_ADDR16) ? 65536 : 256); 657 658 if ((pdata.flags & AT24_FLAG_SERIAL) && (pdata.flags & AT24_FLAG_MAC)) { 659 dev_err(dev, 660 "invalid device data - cannot have both AT24_FLAG_SERIAL & AT24_FLAG_MAC."); 661 return -EINVAL; 662 } 663 664 regmap_config.val_bits = 8; 665 regmap_config.reg_bits = (pdata.flags & AT24_FLAG_ADDR16) ? 16 : 8; 666 regmap_config.disable_locking = true; 667 668 regmap = devm_regmap_init_i2c(client, ®map_config); 669 if (IS_ERR(regmap)) 670 return PTR_ERR(regmap); 671 672 at24_size = sizeof(*at24) + num_addresses * sizeof(struct at24_client); 673 at24 = devm_kzalloc(dev, at24_size, GFP_KERNEL); 674 if (!at24) 675 return -ENOMEM; 676 677 mutex_init(&at24->lock); 678 at24->byte_len = pdata.byte_len; 679 at24->page_size = pdata.page_size; 680 at24->flags = pdata.flags; 681 at24->num_addresses = num_addresses; 682 at24->offset_adj = at24_get_offset_adj(pdata.flags, pdata.byte_len); 683 at24->client[0].client = client; 684 at24->client[0].regmap = regmap; 685 686 at24->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_HIGH); 687 if (IS_ERR(at24->wp_gpio)) 688 return PTR_ERR(at24->wp_gpio); 689 690 writable = !(pdata.flags & AT24_FLAG_READONLY); 691 if (writable) { 692 at24->write_max = min_t(unsigned int, 693 pdata.page_size, at24_io_limit); 694 if (!i2c_fn_i2c && at24->write_max > I2C_SMBUS_BLOCK_MAX) 695 at24->write_max = I2C_SMBUS_BLOCK_MAX; 696 } 697 698 /* use dummy devices for multiple-address chips */ 699 for (i = 1; i < num_addresses; i++) { 700 err = at24_make_dummy_client(at24, i, ®map_config); 701 if (err) { 702 at24_remove_dummy_clients(at24); 703 return err; 704 } 705 } 706 707 i2c_set_clientdata(client, at24); 708 709 /* enable runtime pm */ 710 pm_runtime_set_active(dev); 711 pm_runtime_enable(dev); 712 713 /* 714 * Perform a one-byte test read to verify that the 715 * chip is functional. 716 */ 717 err = at24_read(at24, 0, &test_byte, 1); 718 pm_runtime_idle(dev); 719 if (err) { 720 err = -ENODEV; 721 goto err_clients; 722 } 723 724 nvmem_config.name = dev_name(dev); 725 nvmem_config.dev = dev; 726 nvmem_config.read_only = !writable; 727 nvmem_config.root_only = true; 728 nvmem_config.owner = THIS_MODULE; 729 nvmem_config.compat = true; 730 nvmem_config.base_dev = dev; 731 nvmem_config.reg_read = at24_read; 732 nvmem_config.reg_write = at24_write; 733 nvmem_config.priv = at24; 734 nvmem_config.stride = 1; 735 nvmem_config.word_size = 1; 736 nvmem_config.size = pdata.byte_len; 737 738 at24->nvmem = devm_nvmem_register(dev, &nvmem_config); 739 if (IS_ERR(at24->nvmem)) { 740 err = PTR_ERR(at24->nvmem); 741 goto err_clients; 742 } 743 744 dev_info(dev, "%u byte %s EEPROM, %s, %u bytes/write\n", 745 pdata.byte_len, client->name, 746 writable ? "writable" : "read-only", at24->write_max); 747 748 /* export data to kernel code */ 749 if (pdata.setup) 750 pdata.setup(at24->nvmem, pdata.context); 751 752 return 0; 753 754 err_clients: 755 at24_remove_dummy_clients(at24); 756 pm_runtime_disable(dev); 757 758 return err; 759 } 760 761 static int at24_remove(struct i2c_client *client) 762 { 763 struct at24_data *at24; 764 765 at24 = i2c_get_clientdata(client); 766 767 at24_remove_dummy_clients(at24); 768 pm_runtime_disable(&client->dev); 769 pm_runtime_set_suspended(&client->dev); 770 771 return 0; 772 } 773 774 static struct i2c_driver at24_driver = { 775 .driver = { 776 .name = "at24", 777 .of_match_table = at24_of_match, 778 .acpi_match_table = ACPI_PTR(at24_acpi_ids), 779 }, 780 .probe_new = at24_probe, 781 .remove = at24_remove, 782 .id_table = at24_ids, 783 }; 784 785 static int __init at24_init(void) 786 { 787 if (!at24_io_limit) { 788 pr_err("at24: at24_io_limit must not be 0!\n"); 789 return -EINVAL; 790 } 791 792 at24_io_limit = rounddown_pow_of_two(at24_io_limit); 793 return i2c_add_driver(&at24_driver); 794 } 795 module_init(at24_init); 796 797 static void __exit at24_exit(void) 798 { 799 i2c_del_driver(&at24_driver); 800 } 801 module_exit(at24_exit); 802 803 MODULE_DESCRIPTION("Driver for most I2C EEPROMs"); 804 MODULE_AUTHOR("David Brownell and Wolfram Sang"); 805 MODULE_LICENSE("GPL"); 806