1// SPDX-License-Identifier: GPL-2.0-or-later 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/acpi.h> 10#include <linux/bitops.h> 11#include <linux/capability.h> 12#include <linux/delay.h> 13#include <linux/i2c.h> 14#include <linux/init.h> 15#include <linux/jiffies.h> 16#include <linux/kernel.h> 17#include <linux/mod_devicetable.h> 18#include <linux/module.h> 19#include <linux/mutex.h> 20#include <linux/nvmem-provider.h> 21#include <linux/of.h> 22#include <linux/of_device.h> 23#include <linux/pm_runtime.h> 24#include <linux/property.h> 25#include <linux/regmap.h> 26#include <linux/regulator/consumer.h> 27#include <linux/slab.h> 28 29/* Address pointer is 16 bit. */ 30#define AT24_FLAG_ADDR16 BIT(7) 31/* sysfs-entry will be read-only. */ 32#define AT24_FLAG_READONLY BIT(6) 33/* sysfs-entry will be world-readable. */ 34#define AT24_FLAG_IRUGO BIT(5) 35/* Take always 8 addresses (24c00). */ 36#define AT24_FLAG_TAKE8ADDR BIT(4) 37/* Factory-programmed serial number. */ 38#define AT24_FLAG_SERIAL BIT(3) 39/* Factory-programmed mac address. */ 40#define AT24_FLAG_MAC BIT(2) 41/* Does not auto-rollover reads to the next slave address. */ 42#define AT24_FLAG_NO_RDROL BIT(1) 43 44/* 45 * I2C EEPROMs from most vendors are inexpensive and mostly interchangeable. 46 * Differences between different vendor product lines (like Atmel AT24C or 47 * MicroChip 24LC, etc) won't much matter for typical read/write access. 48 * There are also I2C RAM chips, likewise interchangeable. One example 49 * would be the PCF8570, which acts like a 24c02 EEPROM (256 bytes). 50 * 51 * However, misconfiguration can lose data. "Set 16-bit memory address" 52 * to a part with 8-bit addressing will overwrite data. Writing with too 53 * big a page size also loses data. And it's not safe to assume that the 54 * conventional addresses 0x50..0x57 only hold eeproms; a PCF8563 RTC 55 * uses 0x51, for just one example. 56 * 57 * Accordingly, explicit board-specific configuration data should be used 58 * in almost all cases. (One partial exception is an SMBus used to access 59 * "SPD" data for DRAM sticks. Those only use 24c02 EEPROMs.) 60 * 61 * So this driver uses "new style" I2C driver binding, expecting to be 62 * told what devices exist. That may be in arch/X/mach-Y/board-Z.c or 63 * similar kernel-resident tables; or, configuration data coming from 64 * a bootloader. 65 * 66 * Other than binding model, current differences from "eeprom" driver are 67 * that this one handles write access and isn't restricted to 24c02 devices. 68 * It also handles larger devices (32 kbit and up) with two-byte addresses, 69 * which won't work on pure SMBus systems. 70 */ 71 72struct at24_data { 73 /* 74 * Lock protects against activities from other Linux tasks, 75 * but not from changes by other I2C masters. 76 */ 77 struct mutex lock; 78 79 unsigned int write_max; 80 unsigned int num_addresses; 81 unsigned int offset_adj; 82 83 u32 byte_len; 84 u16 page_size; 85 u8 flags; 86 87 struct nvmem_device *nvmem; 88 struct regulator *vcc_reg; 89 void (*read_post)(unsigned int off, char *buf, size_t count); 90 91 /* 92 * Some chips tie up multiple I2C addresses; dummy devices reserve 93 * them for us. 94 */ 95 u8 bank_addr_shift; 96 struct regmap *client_regmaps[] __counted_by(num_addresses); 97}; 98 99/* 100 * This parameter is to help this driver avoid blocking other drivers out 101 * of I2C for potentially troublesome amounts of time. With a 100 kHz I2C 102 * clock, one 256 byte read takes about 1/43 second which is excessive; 103 * but the 1/170 second it takes at 400 kHz may be quite reasonable; and 104 * at 1 MHz (Fm+) a 1/430 second delay could easily be invisible. 105 * 106 * This value is forced to be a power of two so that writes align on pages. 107 */ 108static unsigned int at24_io_limit = 128; 109module_param_named(io_limit, at24_io_limit, uint, 0); 110MODULE_PARM_DESC(at24_io_limit, "Maximum bytes per I/O (default 128)"); 111 112/* 113 * Specs often allow 5 msec for a page write, sometimes 20 msec; 114 * it's important to recover from write timeouts. 115 */ 116static unsigned int at24_write_timeout = 25; 117module_param_named(write_timeout, at24_write_timeout, uint, 0); 118MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)"); 119 120struct at24_chip_data { 121 u32 byte_len; 122 u8 flags; 123 u8 bank_addr_shift; 124 void (*read_post)(unsigned int off, char *buf, size_t count); 125}; 126 127#define AT24_CHIP_DATA(_name, _len, _flags) \ 128 static const struct at24_chip_data _name = { \ 129 .byte_len = _len, .flags = _flags, \ 130 } 131 132#define AT24_CHIP_DATA_CB(_name, _len, _flags, _read_post) \ 133 static const struct at24_chip_data _name = { \ 134 .byte_len = _len, .flags = _flags, \ 135 .read_post = _read_post, \ 136 } 137 138#define AT24_CHIP_DATA_BS(_name, _len, _flags, _bank_addr_shift) \ 139 static const struct at24_chip_data _name = { \ 140 .byte_len = _len, .flags = _flags, \ 141 .bank_addr_shift = _bank_addr_shift \ 142 } 143 144static void at24_read_post_vaio(unsigned int off, char *buf, size_t count) 145{ 146 int i; 147 148 if (capable(CAP_SYS_ADMIN)) 149 return; 150 151 /* 152 * Hide VAIO private settings to regular users: 153 * - BIOS passwords: bytes 0x00 to 0x0f 154 * - UUID: bytes 0x10 to 0x1f 155 * - Serial number: 0xc0 to 0xdf 156 */ 157 for (i = 0; i < count; i++) { 158 if ((off + i <= 0x1f) || 159 (off + i >= 0xc0 && off + i <= 0xdf)) 160 buf[i] = 0; 161 } 162} 163 164/* needs 8 addresses as A0-A2 are ignored */ 165AT24_CHIP_DATA(at24_data_24c00, 128 / 8, AT24_FLAG_TAKE8ADDR); 166/* old variants can't be handled with this generic entry! */ 167AT24_CHIP_DATA(at24_data_24c01, 1024 / 8, 0); 168AT24_CHIP_DATA(at24_data_24cs01, 16, 169 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 170AT24_CHIP_DATA(at24_data_24c02, 2048 / 8, 0); 171AT24_CHIP_DATA(at24_data_24cs02, 16, 172 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 173AT24_CHIP_DATA(at24_data_24mac402, 48 / 8, 174 AT24_FLAG_MAC | AT24_FLAG_READONLY); 175AT24_CHIP_DATA(at24_data_24mac602, 64 / 8, 176 AT24_FLAG_MAC | AT24_FLAG_READONLY); 177/* spd is a 24c02 in memory DIMMs */ 178AT24_CHIP_DATA(at24_data_spd, 2048 / 8, 179 AT24_FLAG_READONLY | AT24_FLAG_IRUGO); 180/* 24c02_vaio is a 24c02 on some Sony laptops */ 181AT24_CHIP_DATA_CB(at24_data_24c02_vaio, 2048 / 8, 182 AT24_FLAG_READONLY | AT24_FLAG_IRUGO, 183 at24_read_post_vaio); 184AT24_CHIP_DATA(at24_data_24c04, 4096 / 8, 0); 185AT24_CHIP_DATA(at24_data_24cs04, 16, 186 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 187/* 24rf08 quirk is handled at i2c-core */ 188AT24_CHIP_DATA(at24_data_24c08, 8192 / 8, 0); 189AT24_CHIP_DATA(at24_data_24cs08, 16, 190 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 191AT24_CHIP_DATA(at24_data_24c16, 16384 / 8, 0); 192AT24_CHIP_DATA(at24_data_24cs16, 16, 193 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 194AT24_CHIP_DATA(at24_data_24c32, 32768 / 8, AT24_FLAG_ADDR16); 195/* M24C32-D Additional Write lockable page (M24C32-D order codes) */ 196AT24_CHIP_DATA(at24_data_24c32d_wlp, 32, AT24_FLAG_ADDR16); 197AT24_CHIP_DATA(at24_data_24cs32, 16, 198 AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 199AT24_CHIP_DATA(at24_data_24c64, 65536 / 8, AT24_FLAG_ADDR16); 200/* M24C64-D Additional Write lockable page (M24C64-D order codes) */ 201AT24_CHIP_DATA(at24_data_24c64d_wlp, 32, AT24_FLAG_ADDR16); 202AT24_CHIP_DATA(at24_data_24cs64, 16, 203 AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 204AT24_CHIP_DATA(at24_data_24c128, 131072 / 8, AT24_FLAG_ADDR16); 205AT24_CHIP_DATA(at24_data_24c256, 262144 / 8, AT24_FLAG_ADDR16); 206AT24_CHIP_DATA(at24_data_24c512, 524288 / 8, AT24_FLAG_ADDR16); 207AT24_CHIP_DATA(at24_data_24c1024, 1048576 / 8, AT24_FLAG_ADDR16); 208AT24_CHIP_DATA_BS(at24_data_24c1025, 1048576 / 8, AT24_FLAG_ADDR16, 2); 209AT24_CHIP_DATA(at24_data_24c2048, 2097152 / 8, AT24_FLAG_ADDR16); 210/* identical to 24c08 ? */ 211AT24_CHIP_DATA(at24_data_INT3499, 8192 / 8, 0); 212 213static const struct i2c_device_id at24_ids[] = { 214 { "24c00", (kernel_ulong_t)&at24_data_24c00 }, 215 { "24c01", (kernel_ulong_t)&at24_data_24c01 }, 216 { "24cs01", (kernel_ulong_t)&at24_data_24cs01 }, 217 { "24c02", (kernel_ulong_t)&at24_data_24c02 }, 218 { "24cs02", (kernel_ulong_t)&at24_data_24cs02 }, 219 { "24mac402", (kernel_ulong_t)&at24_data_24mac402 }, 220 { "24mac602", (kernel_ulong_t)&at24_data_24mac602 }, 221 { "spd", (kernel_ulong_t)&at24_data_spd }, 222 { "24c02-vaio", (kernel_ulong_t)&at24_data_24c02_vaio }, 223 { "24c04", (kernel_ulong_t)&at24_data_24c04 }, 224 { "24cs04", (kernel_ulong_t)&at24_data_24cs04 }, 225 { "24c08", (kernel_ulong_t)&at24_data_24c08 }, 226 { "24cs08", (kernel_ulong_t)&at24_data_24cs08 }, 227 { "24c16", (kernel_ulong_t)&at24_data_24c16 }, 228 { "24cs16", (kernel_ulong_t)&at24_data_24cs16 }, 229 { "24c32", (kernel_ulong_t)&at24_data_24c32 }, 230 { "24c32d-wl", (kernel_ulong_t)&at24_data_24c32d_wlp }, 231 { "24cs32", (kernel_ulong_t)&at24_data_24cs32 }, 232 { "24c64", (kernel_ulong_t)&at24_data_24c64 }, 233 { "24c64-wl", (kernel_ulong_t)&at24_data_24c64d_wlp }, 234 { "24cs64", (kernel_ulong_t)&at24_data_24cs64 }, 235 { "24c128", (kernel_ulong_t)&at24_data_24c128 }, 236 { "24c256", (kernel_ulong_t)&at24_data_24c256 }, 237 { "24c512", (kernel_ulong_t)&at24_data_24c512 }, 238 { "24c1024", (kernel_ulong_t)&at24_data_24c1024 }, 239 { "24c1025", (kernel_ulong_t)&at24_data_24c1025 }, 240 { "24c2048", (kernel_ulong_t)&at24_data_24c2048 }, 241 { "at24", 0 }, 242 { /* END OF LIST */ } 243}; 244MODULE_DEVICE_TABLE(i2c, at24_ids); 245 246static const struct of_device_id __maybe_unused at24_of_match[] = { 247 { .compatible = "atmel,24c00", .data = &at24_data_24c00 }, 248 { .compatible = "atmel,24c01", .data = &at24_data_24c01 }, 249 { .compatible = "atmel,24cs01", .data = &at24_data_24cs01 }, 250 { .compatible = "atmel,24c02", .data = &at24_data_24c02 }, 251 { .compatible = "atmel,24cs02", .data = &at24_data_24cs02 }, 252 { .compatible = "atmel,24mac402", .data = &at24_data_24mac402 }, 253 { .compatible = "atmel,24mac602", .data = &at24_data_24mac602 }, 254 { .compatible = "atmel,spd", .data = &at24_data_spd }, 255 { .compatible = "atmel,24c04", .data = &at24_data_24c04 }, 256 { .compatible = "atmel,24cs04", .data = &at24_data_24cs04 }, 257 { .compatible = "atmel,24c08", .data = &at24_data_24c08 }, 258 { .compatible = "atmel,24cs08", .data = &at24_data_24cs08 }, 259 { .compatible = "atmel,24c16", .data = &at24_data_24c16 }, 260 { .compatible = "atmel,24cs16", .data = &at24_data_24cs16 }, 261 { .compatible = "atmel,24c32", .data = &at24_data_24c32 }, 262 { .compatible = "atmel,24c32d-wl", .data = &at24_data_24c32d_wlp }, 263 { .compatible = "atmel,24cs32", .data = &at24_data_24cs32 }, 264 { .compatible = "atmel,24c64", .data = &at24_data_24c64 }, 265 { .compatible = "atmel,24c64d-wl", .data = &at24_data_24c64d_wlp }, 266 { .compatible = "atmel,24cs64", .data = &at24_data_24cs64 }, 267 { .compatible = "atmel,24c128", .data = &at24_data_24c128 }, 268 { .compatible = "atmel,24c256", .data = &at24_data_24c256 }, 269 { .compatible = "atmel,24c512", .data = &at24_data_24c512 }, 270 { .compatible = "atmel,24c1024", .data = &at24_data_24c1024 }, 271 { .compatible = "atmel,24c1025", .data = &at24_data_24c1025 }, 272 { .compatible = "atmel,24c2048", .data = &at24_data_24c2048 }, 273 { /* END OF LIST */ }, 274}; 275MODULE_DEVICE_TABLE(of, at24_of_match); 276 277static const struct acpi_device_id __maybe_unused at24_acpi_ids[] = { 278 { "INT3499", (kernel_ulong_t)&at24_data_INT3499 }, 279 { "TPF0001", (kernel_ulong_t)&at24_data_24c1024 }, 280 { /* END OF LIST */ } 281}; 282MODULE_DEVICE_TABLE(acpi, at24_acpi_ids); 283 284/* 285 * This routine supports chips which consume multiple I2C addresses. It 286 * computes the addressing information to be used for a given r/w request. 287 * Assumes that sanity checks for offset happened at sysfs-layer. 288 * 289 * Slave address and byte offset derive from the offset. Always 290 * set the byte address; on a multi-master board, another master 291 * may have changed the chip's "current" address pointer. 292 */ 293static struct regmap *at24_translate_offset(struct at24_data *at24, 294 unsigned int *offset) 295{ 296 unsigned int i; 297 298 if (at24->flags & AT24_FLAG_ADDR16) { 299 i = *offset >> 16; 300 *offset &= 0xffff; 301 } else { 302 i = *offset >> 8; 303 *offset &= 0xff; 304 } 305 306 return at24->client_regmaps[i]; 307} 308 309static struct device *at24_base_client_dev(struct at24_data *at24) 310{ 311 return regmap_get_device(at24->client_regmaps[0]); 312} 313 314static size_t at24_adjust_read_count(struct at24_data *at24, 315 unsigned int offset, size_t count) 316{ 317 unsigned int bits; 318 size_t remainder; 319 320 /* 321 * In case of multi-address chips that don't rollover reads to 322 * the next slave address: truncate the count to the slave boundary, 323 * so that the read never straddles slaves. 324 */ 325 if (at24->flags & AT24_FLAG_NO_RDROL) { 326 bits = (at24->flags & AT24_FLAG_ADDR16) ? 16 : 8; 327 remainder = BIT(bits) - offset; 328 if (count > remainder) 329 count = remainder; 330 } 331 332 if (count > at24_io_limit) 333 count = at24_io_limit; 334 335 return count; 336} 337 338static ssize_t at24_regmap_read(struct at24_data *at24, char *buf, 339 unsigned int offset, size_t count) 340{ 341 unsigned long timeout, read_time; 342 struct regmap *regmap; 343 int ret; 344 345 regmap = at24_translate_offset(at24, &offset); 346 count = at24_adjust_read_count(at24, offset, count); 347 348 /* adjust offset for mac and serial read ops */ 349 offset += at24->offset_adj; 350 351 timeout = jiffies + msecs_to_jiffies(at24_write_timeout); 352 do { 353 /* 354 * The timestamp shall be taken before the actual operation 355 * to avoid a premature timeout in case of high CPU load. 356 */ 357 read_time = jiffies; 358 359 ret = regmap_bulk_read(regmap, offset, buf, count); 360 dev_dbg(regmap_get_device(regmap), "read %zu@%d --> %d (%ld)\n", 361 count, offset, ret, jiffies); 362 if (!ret) 363 return count; 364 365 usleep_range(1000, 1500); 366 } while (time_before(read_time, timeout)); 367 368 return -ETIMEDOUT; 369} 370 371/* 372 * Note that if the hardware write-protect pin is pulled high, the whole 373 * chip is normally write protected. But there are plenty of product 374 * variants here, including OTP fuses and partial chip protect. 375 * 376 * We only use page mode writes; the alternative is sloooow. These routines 377 * write at most one page. 378 */ 379 380static size_t at24_adjust_write_count(struct at24_data *at24, 381 unsigned int offset, size_t count) 382{ 383 unsigned int next_page; 384 385 /* write_max is at most a page */ 386 if (count > at24->write_max) 387 count = at24->write_max; 388 389 /* Never roll over backwards, to the start of this page */ 390 next_page = roundup(offset + 1, at24->page_size); 391 if (offset + count > next_page) 392 count = next_page - offset; 393 394 return count; 395} 396 397static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf, 398 unsigned int offset, size_t count) 399{ 400 unsigned long timeout, write_time; 401 struct regmap *regmap; 402 int ret; 403 404 regmap = at24_translate_offset(at24, &offset); 405 count = at24_adjust_write_count(at24, offset, count); 406 timeout = jiffies + msecs_to_jiffies(at24_write_timeout); 407 408 do { 409 /* 410 * The timestamp shall be taken before the actual operation 411 * to avoid a premature timeout in case of high CPU load. 412 */ 413 write_time = jiffies; 414 415 ret = regmap_bulk_write(regmap, offset, buf, count); 416 dev_dbg(regmap_get_device(regmap), "write %zu@%d --> %d (%ld)\n", 417 count, offset, ret, jiffies); 418 if (!ret) 419 return count; 420 421 usleep_range(1000, 1500); 422 } while (time_before(write_time, timeout)); 423 424 return -ETIMEDOUT; 425} 426 427static int at24_read(void *priv, unsigned int off, void *val, size_t count) 428{ 429 struct at24_data *at24; 430 struct device *dev; 431 char *buf = val; 432 int i, ret; 433 434 at24 = priv; 435 dev = at24_base_client_dev(at24); 436 437 if (unlikely(!count)) 438 return count; 439 440 if (off + count > at24->byte_len) 441 return -EINVAL; 442 443 ret = pm_runtime_resume_and_get(dev); 444 if (ret) 445 return ret; 446 /* 447 * Read data from chip, protecting against concurrent updates 448 * from this host, but not from other I2C masters. 449 */ 450 mutex_lock(&at24->lock); 451 452 for (i = 0; count; i += ret, count -= ret) { 453 ret = at24_regmap_read(at24, buf + i, off + i, count); 454 if (ret < 0) { 455 mutex_unlock(&at24->lock); 456 pm_runtime_put(dev); 457 return ret; 458 } 459 } 460 461 mutex_unlock(&at24->lock); 462 463 pm_runtime_put(dev); 464 465 if (unlikely(at24->read_post)) 466 at24->read_post(off, buf, i); 467 468 return 0; 469} 470 471static int at24_write(void *priv, unsigned int off, void *val, size_t count) 472{ 473 struct at24_data *at24; 474 struct device *dev; 475 char *buf = val; 476 int ret; 477 478 at24 = priv; 479 dev = at24_base_client_dev(at24); 480 481 if (unlikely(!count)) 482 return -EINVAL; 483 484 if (off + count > at24->byte_len) 485 return -EINVAL; 486 487 ret = pm_runtime_resume_and_get(dev); 488 if (ret) 489 return ret; 490 /* 491 * Write data to chip, protecting against concurrent updates 492 * from this host, but not from other I2C masters. 493 */ 494 mutex_lock(&at24->lock); 495 496 while (count) { 497 ret = at24_regmap_write(at24, buf, off, count); 498 if (ret < 0) { 499 mutex_unlock(&at24->lock); 500 pm_runtime_put(dev); 501 return ret; 502 } 503 buf += ret; 504 off += ret; 505 count -= ret; 506 } 507 508 mutex_unlock(&at24->lock); 509 510 pm_runtime_put(dev); 511 512 return 0; 513} 514 515static int at24_make_dummy_client(struct at24_data *at24, unsigned int index, 516 struct i2c_client *base_client, 517 struct regmap_config *regmap_config) 518{ 519 struct i2c_client *dummy_client; 520 struct regmap *regmap; 521 522 dummy_client = devm_i2c_new_dummy_device(&base_client->dev, 523 base_client->adapter, 524 base_client->addr + 525 (index << at24->bank_addr_shift)); 526 if (IS_ERR(dummy_client)) 527 return PTR_ERR(dummy_client); 528 529 regmap = devm_regmap_init_i2c(dummy_client, regmap_config); 530 if (IS_ERR(regmap)) 531 return PTR_ERR(regmap); 532 533 at24->client_regmaps[index] = regmap; 534 535 return 0; 536} 537 538static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len) 539{ 540 if (flags & AT24_FLAG_MAC) { 541 /* EUI-48 starts from 0x9a, EUI-64 from 0x98 */ 542 return 0xa0 - byte_len; 543 } else if (flags & AT24_FLAG_SERIAL && flags & AT24_FLAG_ADDR16) { 544 /* 545 * For 16 bit address pointers, the word address must contain 546 * a '10' sequence in bits 11 and 10 regardless of the 547 * intended position of the address pointer. 548 */ 549 return 0x0800; 550 } else if (flags & AT24_FLAG_SERIAL) { 551 /* 552 * Otherwise the word address must begin with a '10' sequence, 553 * regardless of the intended address. 554 */ 555 return 0x0080; 556 } else { 557 return 0; 558 } 559} 560 561static void at24_probe_temp_sensor(struct i2c_client *client) 562{ 563 struct at24_data *at24 = i2c_get_clientdata(client); 564 struct i2c_board_info info = { .type = "jc42" }; 565 int ret; 566 u8 val; 567 568 /* 569 * Byte 2 has value 11 for DDR3, earlier versions don't 570 * support the thermal sensor present flag 571 */ 572 ret = at24_read(at24, 2, &val, 1); 573 if (ret || val != 11) 574 return; 575 576 /* Byte 32, bit 7 is set if temp sensor is present */ 577 ret = at24_read(at24, 32, &val, 1); 578 if (ret || !(val & BIT(7))) 579 return; 580 581 info.addr = 0x18 | (client->addr & 7); 582 583 i2c_new_client_device(client->adapter, &info); 584} 585 586static int at24_probe(struct i2c_client *client) 587{ 588 struct regmap_config regmap_config = { }; 589 struct nvmem_config nvmem_config = { }; 590 u32 byte_len, page_size, flags, addrw; 591 const struct at24_chip_data *cdata; 592 struct device *dev = &client->dev; 593 bool i2c_fn_i2c, i2c_fn_block; 594 unsigned int i, num_addresses; 595 struct at24_data *at24; 596 bool full_power; 597 struct regmap *regmap; 598 bool writable; 599 u8 test_byte; 600 int err; 601 602 i2c_fn_i2c = i2c_check_functionality(client->adapter, I2C_FUNC_I2C); 603 i2c_fn_block = i2c_check_functionality(client->adapter, 604 I2C_FUNC_SMBUS_WRITE_I2C_BLOCK); 605 606 cdata = i2c_get_match_data(client); 607 if (!cdata) 608 return -ENODEV; 609 610 err = device_property_read_u32(dev, "pagesize", &page_size); 611 if (err) 612 /* 613 * This is slow, but we can't know all eeproms, so we better 614 * play safe. Specifying custom eeprom-types via device tree 615 * or properties is recommended anyhow. 616 */ 617 page_size = 1; 618 619 flags = cdata->flags; 620 if (device_property_present(dev, "read-only")) 621 flags |= AT24_FLAG_READONLY; 622 if (device_property_present(dev, "no-read-rollover")) 623 flags |= AT24_FLAG_NO_RDROL; 624 625 err = device_property_read_u32(dev, "address-width", &addrw); 626 if (!err) { 627 switch (addrw) { 628 case 8: 629 if (flags & AT24_FLAG_ADDR16) 630 dev_warn(dev, 631 "Override address width to be 8, while default is 16\n"); 632 flags &= ~AT24_FLAG_ADDR16; 633 break; 634 case 16: 635 flags |= AT24_FLAG_ADDR16; 636 break; 637 default: 638 dev_warn(dev, "Bad \"address-width\" property: %u\n", 639 addrw); 640 } 641 } 642 643 err = device_property_read_u32(dev, "size", &byte_len); 644 if (err) 645 byte_len = cdata->byte_len; 646 647 if (!i2c_fn_i2c && !i2c_fn_block) 648 page_size = 1; 649 650 if (!page_size) { 651 dev_err(dev, "page_size must not be 0!\n"); 652 return -EINVAL; 653 } 654 655 if (!is_power_of_2(page_size)) 656 dev_warn(dev, "page_size looks suspicious (no power of 2)!\n"); 657 658 err = device_property_read_u32(dev, "num-addresses", &num_addresses); 659 if (err) { 660 if (flags & AT24_FLAG_TAKE8ADDR) 661 num_addresses = 8; 662 else 663 num_addresses = DIV_ROUND_UP(byte_len, 664 (flags & AT24_FLAG_ADDR16) ? 65536 : 256); 665 } 666 667 if ((flags & AT24_FLAG_SERIAL) && (flags & AT24_FLAG_MAC)) { 668 dev_err(dev, 669 "invalid device data - cannot have both AT24_FLAG_SERIAL & AT24_FLAG_MAC."); 670 return -EINVAL; 671 } 672 673 regmap_config.val_bits = 8; 674 regmap_config.reg_bits = (flags & AT24_FLAG_ADDR16) ? 16 : 8; 675 regmap_config.disable_locking = true; 676 677 regmap = devm_regmap_init_i2c(client, ®map_config); 678 if (IS_ERR(regmap)) 679 return PTR_ERR(regmap); 680 681 at24 = devm_kzalloc(dev, struct_size(at24, client_regmaps, num_addresses), 682 GFP_KERNEL); 683 if (!at24) 684 return -ENOMEM; 685 686 mutex_init(&at24->lock); 687 at24->byte_len = byte_len; 688 at24->page_size = page_size; 689 at24->flags = flags; 690 at24->read_post = cdata->read_post; 691 at24->bank_addr_shift = cdata->bank_addr_shift; 692 at24->num_addresses = num_addresses; 693 at24->offset_adj = at24_get_offset_adj(flags, byte_len); 694 at24->client_regmaps[0] = regmap; 695 696 at24->vcc_reg = devm_regulator_get(dev, "vcc"); 697 if (IS_ERR(at24->vcc_reg)) 698 return PTR_ERR(at24->vcc_reg); 699 700 writable = !(flags & AT24_FLAG_READONLY); 701 if (writable) { 702 at24->write_max = min_t(unsigned int, 703 page_size, at24_io_limit); 704 if (!i2c_fn_i2c && at24->write_max > I2C_SMBUS_BLOCK_MAX) 705 at24->write_max = I2C_SMBUS_BLOCK_MAX; 706 } 707 708 /* use dummy devices for multiple-address chips */ 709 for (i = 1; i < num_addresses; i++) { 710 err = at24_make_dummy_client(at24, i, client, ®map_config); 711 if (err) 712 return err; 713 } 714 715 /* 716 * We initialize nvmem_config.id to NVMEM_DEVID_AUTO even if the 717 * label property is set as some platform can have multiple eeproms 718 * with same label and we can not register each of those with same 719 * label. Failing to register those eeproms trigger cascade failure 720 * on such platform. 721 */ 722 nvmem_config.id = NVMEM_DEVID_AUTO; 723 724 if (device_property_present(dev, "label")) { 725 err = device_property_read_string(dev, "label", 726 &nvmem_config.name); 727 if (err) 728 return err; 729 } else { 730 nvmem_config.name = dev_name(dev); 731 } 732 733 nvmem_config.type = NVMEM_TYPE_EEPROM; 734 nvmem_config.dev = dev; 735 nvmem_config.read_only = !writable; 736 nvmem_config.root_only = !(flags & AT24_FLAG_IRUGO); 737 nvmem_config.owner = THIS_MODULE; 738 nvmem_config.compat = true; 739 nvmem_config.base_dev = dev; 740 nvmem_config.reg_read = at24_read; 741 nvmem_config.reg_write = at24_write; 742 nvmem_config.priv = at24; 743 nvmem_config.stride = 1; 744 nvmem_config.word_size = 1; 745 nvmem_config.size = byte_len; 746 747 i2c_set_clientdata(client, at24); 748 749 full_power = acpi_dev_state_d0(&client->dev); 750 if (full_power) { 751 err = regulator_enable(at24->vcc_reg); 752 if (err) { 753 dev_err(dev, "Failed to enable vcc regulator\n"); 754 return err; 755 } 756 757 pm_runtime_set_active(dev); 758 } 759 pm_runtime_enable(dev); 760 761 at24->nvmem = devm_nvmem_register(dev, &nvmem_config); 762 if (IS_ERR(at24->nvmem)) { 763 pm_runtime_disable(dev); 764 if (!pm_runtime_status_suspended(dev)) 765 regulator_disable(at24->vcc_reg); 766 return dev_err_probe(dev, PTR_ERR(at24->nvmem), 767 "failed to register nvmem\n"); 768 } 769 770 /* 771 * Perform a one-byte test read to verify that the chip is functional, 772 * unless powering on the device is to be avoided during probe (i.e. 773 * it's powered off right now). 774 */ 775 if (full_power) { 776 err = at24_read(at24, 0, &test_byte, 1); 777 if (err) { 778 pm_runtime_disable(dev); 779 if (!pm_runtime_status_suspended(dev)) 780 regulator_disable(at24->vcc_reg); 781 return -ENODEV; 782 } 783 } 784 785 /* If this a SPD EEPROM, probe for DDR3 thermal sensor */ 786 if (cdata == &at24_data_spd) 787 at24_probe_temp_sensor(client); 788 789 pm_runtime_idle(dev); 790 791 if (writable) 792 dev_info(dev, "%u byte %s EEPROM, writable, %u bytes/write\n", 793 byte_len, client->name, at24->write_max); 794 else 795 dev_info(dev, "%u byte %s EEPROM, read-only\n", 796 byte_len, client->name); 797 798 return 0; 799} 800 801static void at24_remove(struct i2c_client *client) 802{ 803 struct at24_data *at24 = i2c_get_clientdata(client); 804 805 pm_runtime_disable(&client->dev); 806 if (acpi_dev_state_d0(&client->dev)) { 807 if (!pm_runtime_status_suspended(&client->dev)) 808 regulator_disable(at24->vcc_reg); 809 pm_runtime_set_suspended(&client->dev); 810 } 811} 812 813static int __maybe_unused at24_suspend(struct device *dev) 814{ 815 struct i2c_client *client = to_i2c_client(dev); 816 struct at24_data *at24 = i2c_get_clientdata(client); 817 818 return regulator_disable(at24->vcc_reg); 819} 820 821static int __maybe_unused at24_resume(struct device *dev) 822{ 823 struct i2c_client *client = to_i2c_client(dev); 824 struct at24_data *at24 = i2c_get_clientdata(client); 825 826 return regulator_enable(at24->vcc_reg); 827} 828 829static const struct dev_pm_ops at24_pm_ops = { 830 SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, 831 pm_runtime_force_resume) 832 SET_RUNTIME_PM_OPS(at24_suspend, at24_resume, NULL) 833}; 834 835static struct i2c_driver at24_driver = { 836 .driver = { 837 .name = "at24", 838 .pm = &at24_pm_ops, 839 .of_match_table = of_match_ptr(at24_of_match), 840 .acpi_match_table = ACPI_PTR(at24_acpi_ids), 841 }, 842 .probe = at24_probe, 843 .remove = at24_remove, 844 .id_table = at24_ids, 845 .flags = I2C_DRV_ACPI_WAIVE_D0_PROBE, 846}; 847 848static int __init at24_init(void) 849{ 850 if (!at24_io_limit) { 851 pr_err("at24: at24_io_limit must not be 0!\n"); 852 return -EINVAL; 853 } 854 855 at24_io_limit = rounddown_pow_of_two(at24_io_limit); 856 return i2c_add_driver(&at24_driver); 857} 858module_init(at24_init); 859 860static void __exit at24_exit(void) 861{ 862 i2c_del_driver(&at24_driver); 863} 864module_exit(at24_exit); 865 866MODULE_DESCRIPTION("Driver for most I2C EEPROMs"); 867MODULE_AUTHOR("David Brownell and Wolfram Sang"); 868MODULE_LICENSE("GPL"); 869