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