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/module.h> 18 #include <linux/mutex.h> 19 #include <linux/nvmem-provider.h> 20 #include <linux/pm_runtime.h> 21 #include <linux/property.h> 22 #include <linux/regmap.h> 23 #include <linux/regulator/consumer.h> 24 #include <linux/slab.h> 25 26 /* Address pointer is 16 bit. */ 27 #define AT24_FLAG_ADDR16 BIT(7) 28 /* sysfs-entry will be read-only. */ 29 #define AT24_FLAG_READONLY BIT(6) 30 /* sysfs-entry will be world-readable. */ 31 #define AT24_FLAG_IRUGO BIT(5) 32 /* Take always 8 addresses (24c00). */ 33 #define AT24_FLAG_TAKE8ADDR BIT(4) 34 /* Factory-programmed serial number. */ 35 #define AT24_FLAG_SERIAL BIT(3) 36 /* Factory-programmed mac address. */ 37 #define AT24_FLAG_MAC BIT(2) 38 /* Does not auto-rollover reads to the next slave address. */ 39 #define AT24_FLAG_NO_RDROL BIT(1) 40 41 /* 42 * I2C EEPROMs from most vendors are inexpensive and mostly interchangeable. 43 * Differences between different vendor product lines (like Atmel AT24C or 44 * MicroChip 24LC, etc) won't much matter for typical read/write access. 45 * There are also I2C RAM chips, likewise interchangeable. One example 46 * would be the PCF8570, which acts like a 24c02 EEPROM (256 bytes). 47 * 48 * However, misconfiguration can lose data. "Set 16-bit memory address" 49 * to a part with 8-bit addressing will overwrite data. Writing with too 50 * big a page size also loses data. And it's not safe to assume that the 51 * conventional addresses 0x50..0x57 only hold eeproms; a PCF8563 RTC 52 * uses 0x51, for just one example. 53 * 54 * Accordingly, explicit board-specific configuration data should be used 55 * in almost all cases. (One partial exception is an SMBus used to access 56 * "SPD" data for DRAM sticks. Those only use 24c02 EEPROMs.) 57 * 58 * So this driver uses "new style" I2C driver binding, expecting to be 59 * told what devices exist. That may be in arch/X/mach-Y/board-Z.c or 60 * similar kernel-resident tables; or, configuration data coming from 61 * a bootloader. 62 * 63 * Other than binding model, current differences from "eeprom" driver are 64 * that this one handles write access and isn't restricted to 24c02 devices. 65 * It also handles larger devices (32 kbit and up) with two-byte addresses, 66 * which won't work on pure SMBus systems. 67 */ 68 69 struct at24_data { 70 /* 71 * Lock protects against activities from other Linux tasks, 72 * but not from changes by other I2C masters. 73 */ 74 struct mutex lock; 75 76 unsigned int write_max; 77 unsigned int num_addresses; 78 unsigned int offset_adj; 79 80 u32 byte_len; 81 u16 page_size; 82 u8 flags; 83 84 struct nvmem_device *nvmem; 85 struct regulator *vcc_reg; 86 void (*read_post)(unsigned int off, char *buf, size_t count); 87 88 /* 89 * Some chips tie up multiple I2C addresses; dummy devices reserve 90 * them for us. 91 */ 92 u8 bank_addr_shift; 93 struct regmap *client_regmaps[] __counted_by(num_addresses); 94 }; 95 96 /* 97 * This parameter is to help this driver avoid blocking other drivers out 98 * of I2C for potentially troublesome amounts of time. With a 100 kHz I2C 99 * clock, one 256 byte read takes about 1/43 second which is excessive; 100 * but the 1/170 second it takes at 400 kHz may be quite reasonable; and 101 * at 1 MHz (Fm+) a 1/430 second delay could easily be invisible. 102 * 103 * This value is forced to be a power of two so that writes align on pages. 104 */ 105 static unsigned int at24_io_limit = 128; 106 module_param_named(io_limit, at24_io_limit, uint, 0); 107 MODULE_PARM_DESC(at24_io_limit, "Maximum bytes per I/O (default 128)"); 108 109 /* 110 * Specs often allow 5 msec for a page write, sometimes 20 msec; 111 * it's important to recover from write timeouts. 112 */ 113 static unsigned int at24_write_timeout = 25; 114 module_param_named(write_timeout, at24_write_timeout, uint, 0); 115 MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)"); 116 117 struct at24_chip_data { 118 u32 byte_len; 119 u8 flags; 120 u8 bank_addr_shift; 121 void (*read_post)(unsigned int off, char *buf, size_t count); 122 }; 123 124 #define AT24_CHIP_DATA(_name, _len, _flags) \ 125 static const struct at24_chip_data _name = { \ 126 .byte_len = _len, .flags = _flags, \ 127 } 128 129 #define AT24_CHIP_DATA_CB(_name, _len, _flags, _read_post) \ 130 static const struct at24_chip_data _name = { \ 131 .byte_len = _len, .flags = _flags, \ 132 .read_post = _read_post, \ 133 } 134 135 #define AT24_CHIP_DATA_BS(_name, _len, _flags, _bank_addr_shift) \ 136 static const struct at24_chip_data _name = { \ 137 .byte_len = _len, .flags = _flags, \ 138 .bank_addr_shift = _bank_addr_shift \ 139 } 140 141 static void at24_read_post_vaio(unsigned int off, char *buf, size_t count) 142 { 143 int i; 144 145 if (capable(CAP_SYS_ADMIN)) 146 return; 147 148 /* 149 * Hide VAIO private settings to regular users: 150 * - BIOS passwords: bytes 0x00 to 0x0f 151 * - UUID: bytes 0x10 to 0x1f 152 * - Serial number: 0xc0 to 0xdf 153 */ 154 for (i = 0; i < count; i++) { 155 if ((off + i <= 0x1f) || 156 (off + i >= 0xc0 && off + i <= 0xdf)) 157 buf[i] = 0; 158 } 159 } 160 161 /* needs 8 addresses as A0-A2 are ignored */ 162 AT24_CHIP_DATA(at24_data_24c00, 128 / 8, AT24_FLAG_TAKE8ADDR); 163 /* old variants can't be handled with this generic entry! */ 164 AT24_CHIP_DATA(at24_data_24c01, 1024 / 8, 0); 165 AT24_CHIP_DATA(at24_data_24cs01, 16, 166 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 167 AT24_CHIP_DATA(at24_data_24c02, 2048 / 8, 0); 168 AT24_CHIP_DATA(at24_data_24cs02, 16, 169 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 170 AT24_CHIP_DATA(at24_data_24mac402, 48 / 8, 171 AT24_FLAG_MAC | AT24_FLAG_READONLY); 172 AT24_CHIP_DATA(at24_data_24mac602, 64 / 8, 173 AT24_FLAG_MAC | AT24_FLAG_READONLY); 174 AT24_CHIP_DATA(at24_data_24aa025e48, 48 / 8, 175 AT24_FLAG_READONLY); 176 AT24_CHIP_DATA(at24_data_24aa025e64, 64 / 8, 177 AT24_FLAG_READONLY); 178 /* spd is a 24c02 in memory DIMMs */ 179 AT24_CHIP_DATA(at24_data_spd, 2048 / 8, 180 AT24_FLAG_READONLY | AT24_FLAG_IRUGO); 181 /* 24c02_vaio is a 24c02 on some Sony laptops */ 182 AT24_CHIP_DATA_CB(at24_data_24c02_vaio, 2048 / 8, 183 AT24_FLAG_READONLY | AT24_FLAG_IRUGO, 184 at24_read_post_vaio); 185 AT24_CHIP_DATA(at24_data_24c04, 4096 / 8, 0); 186 AT24_CHIP_DATA(at24_data_24cs04, 16, 187 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 188 /* 24rf08 quirk is handled at i2c-core */ 189 AT24_CHIP_DATA(at24_data_24c08, 8192 / 8, 0); 190 AT24_CHIP_DATA(at24_data_24cs08, 16, 191 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 192 AT24_CHIP_DATA(at24_data_24c16, 16384 / 8, 0); 193 AT24_CHIP_DATA(at24_data_24cs16, 16, 194 AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 195 AT24_CHIP_DATA(at24_data_24c32, 32768 / 8, AT24_FLAG_ADDR16); 196 /* M24C32-D Additional Write lockable page (M24C32-D order codes) */ 197 AT24_CHIP_DATA(at24_data_24c32d_wlp, 32, AT24_FLAG_ADDR16); 198 AT24_CHIP_DATA(at24_data_24cs32, 16, 199 AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 200 AT24_CHIP_DATA(at24_data_24c64, 65536 / 8, AT24_FLAG_ADDR16); 201 /* M24C64-D Additional Write lockable page (M24C64-D order codes) */ 202 AT24_CHIP_DATA(at24_data_24c64d_wlp, 32, AT24_FLAG_ADDR16); 203 AT24_CHIP_DATA(at24_data_24cs64, 16, 204 AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY); 205 AT24_CHIP_DATA(at24_data_24c128, 131072 / 8, AT24_FLAG_ADDR16); 206 AT24_CHIP_DATA(at24_data_24c256, 262144 / 8, AT24_FLAG_ADDR16); 207 /* M24256E Additional Write lockable page (M24256E-F order codes) */ 208 AT24_CHIP_DATA(at24_data_24256e_wlp, 64, AT24_FLAG_ADDR16); 209 AT24_CHIP_DATA(at24_data_24c512, 524288 / 8, AT24_FLAG_ADDR16); 210 AT24_CHIP_DATA(at24_data_24c1024, 1048576 / 8, AT24_FLAG_ADDR16); 211 AT24_CHIP_DATA_BS(at24_data_24c1025, 1048576 / 8, AT24_FLAG_ADDR16, 2); 212 AT24_CHIP_DATA(at24_data_24c2048, 2097152 / 8, AT24_FLAG_ADDR16); 213 /* identical to 24c08 ? */ 214 AT24_CHIP_DATA(at24_data_INT3499, 8192 / 8, 0); 215 216 static const struct i2c_device_id at24_ids[] = { 217 { .name = "24c00", .driver_data = (kernel_ulong_t)&at24_data_24c00 }, 218 { .name = "24c01", .driver_data = (kernel_ulong_t)&at24_data_24c01 }, 219 { .name = "24cs01", .driver_data = (kernel_ulong_t)&at24_data_24cs01 }, 220 { .name = "24c02", .driver_data = (kernel_ulong_t)&at24_data_24c02 }, 221 { .name = "24cs02", .driver_data = (kernel_ulong_t)&at24_data_24cs02 }, 222 { .name = "24mac402", .driver_data = (kernel_ulong_t)&at24_data_24mac402 }, 223 { .name = "24mac602", .driver_data = (kernel_ulong_t)&at24_data_24mac602 }, 224 { .name = "24aa025e48", .driver_data = (kernel_ulong_t)&at24_data_24aa025e48 }, 225 { .name = "24aa025e64", .driver_data = (kernel_ulong_t)&at24_data_24aa025e64 }, 226 { .name = "spd", .driver_data = (kernel_ulong_t)&at24_data_spd }, 227 { .name = "24c02-vaio", .driver_data = (kernel_ulong_t)&at24_data_24c02_vaio }, 228 { .name = "24c04", .driver_data = (kernel_ulong_t)&at24_data_24c04 }, 229 { .name = "24cs04", .driver_data = (kernel_ulong_t)&at24_data_24cs04 }, 230 { .name = "24c08", .driver_data = (kernel_ulong_t)&at24_data_24c08 }, 231 { .name = "24cs08", .driver_data = (kernel_ulong_t)&at24_data_24cs08 }, 232 { .name = "24c16", .driver_data = (kernel_ulong_t)&at24_data_24c16 }, 233 { .name = "24cs16", .driver_data = (kernel_ulong_t)&at24_data_24cs16 }, 234 { .name = "24c32", .driver_data = (kernel_ulong_t)&at24_data_24c32 }, 235 { .name = "24c32d-wl", .driver_data = (kernel_ulong_t)&at24_data_24c32d_wlp }, 236 { .name = "24cs32", .driver_data = (kernel_ulong_t)&at24_data_24cs32 }, 237 { .name = "24c64", .driver_data = (kernel_ulong_t)&at24_data_24c64 }, 238 { .name = "24c64-wl", .driver_data = (kernel_ulong_t)&at24_data_24c64d_wlp }, 239 { .name = "24cs64", .driver_data = (kernel_ulong_t)&at24_data_24cs64 }, 240 { .name = "24c128", .driver_data = (kernel_ulong_t)&at24_data_24c128 }, 241 { .name = "24c256", .driver_data = (kernel_ulong_t)&at24_data_24c256 }, 242 { .name = "24256e-wl", .driver_data = (kernel_ulong_t)&at24_data_24256e_wlp }, 243 { .name = "24c512", .driver_data = (kernel_ulong_t)&at24_data_24c512 }, 244 { .name = "24c1024", .driver_data = (kernel_ulong_t)&at24_data_24c1024 }, 245 { .name = "24c1025", .driver_data = (kernel_ulong_t)&at24_data_24c1025 }, 246 { .name = "24c2048", .driver_data = (kernel_ulong_t)&at24_data_24c2048 }, 247 { .name = "at24", .driver_data = 0 }, 248 { /* END OF LIST */ } 249 }; 250 MODULE_DEVICE_TABLE(i2c, at24_ids); 251 252 static const struct of_device_id at24_of_match[] = { 253 { .compatible = "atmel,24c00", .data = &at24_data_24c00 }, 254 { .compatible = "atmel,24c01", .data = &at24_data_24c01 }, 255 { .compatible = "atmel,24cs01", .data = &at24_data_24cs01 }, 256 { .compatible = "atmel,24c02", .data = &at24_data_24c02 }, 257 { .compatible = "atmel,24cs02", .data = &at24_data_24cs02 }, 258 { .compatible = "atmel,24mac402", .data = &at24_data_24mac402 }, 259 { .compatible = "atmel,24mac602", .data = &at24_data_24mac602 }, 260 { .compatible = "atmel,spd", .data = &at24_data_spd }, 261 { .compatible = "atmel,24c04", .data = &at24_data_24c04 }, 262 { .compatible = "atmel,24cs04", .data = &at24_data_24cs04 }, 263 { .compatible = "atmel,24c08", .data = &at24_data_24c08 }, 264 { .compatible = "atmel,24cs08", .data = &at24_data_24cs08 }, 265 { .compatible = "atmel,24c16", .data = &at24_data_24c16 }, 266 { .compatible = "atmel,24cs16", .data = &at24_data_24cs16 }, 267 { .compatible = "atmel,24c32", .data = &at24_data_24c32 }, 268 { .compatible = "atmel,24c32d-wl", .data = &at24_data_24c32d_wlp }, 269 { .compatible = "atmel,24cs32", .data = &at24_data_24cs32 }, 270 { .compatible = "atmel,24c64", .data = &at24_data_24c64 }, 271 { .compatible = "atmel,24c64d-wl", .data = &at24_data_24c64d_wlp }, 272 { .compatible = "atmel,24cs64", .data = &at24_data_24cs64 }, 273 { .compatible = "atmel,24c128", .data = &at24_data_24c128 }, 274 { .compatible = "atmel,24c256", .data = &at24_data_24c256 }, 275 { .compatible = "atmel,24c512", .data = &at24_data_24c512 }, 276 { .compatible = "atmel,24c1024", .data = &at24_data_24c1024 }, 277 { .compatible = "atmel,24c1025", .data = &at24_data_24c1025 }, 278 { .compatible = "atmel,24c2048", .data = &at24_data_24c2048 }, 279 { .compatible = "microchip,24aa025e48", .data = &at24_data_24aa025e48 }, 280 { .compatible = "microchip,24aa025e64", .data = &at24_data_24aa025e64 }, 281 { .compatible = "st,24256e-wl", .data = &at24_data_24256e_wlp }, 282 { /* END OF LIST */ }, 283 }; 284 MODULE_DEVICE_TABLE(of, at24_of_match); 285 286 static const struct acpi_device_id at24_acpi_ids[] = { 287 { "INT3499", (kernel_ulong_t)&at24_data_INT3499 }, 288 { "TPF0001", (kernel_ulong_t)&at24_data_24c1024 }, 289 { /* END OF LIST */ } 290 }; 291 MODULE_DEVICE_TABLE(acpi, at24_acpi_ids); 292 293 /* 294 * This routine supports chips which consume multiple I2C addresses. It 295 * computes the addressing information to be used for a given r/w request. 296 * Assumes that sanity checks for offset happened at sysfs-layer. 297 * 298 * Slave address and byte offset derive from the offset. Always 299 * set the byte address; on a multi-master board, another master 300 * may have changed the chip's "current" address pointer. 301 */ 302 static struct regmap *at24_translate_offset(struct at24_data *at24, 303 unsigned int *offset) 304 { 305 unsigned int i; 306 307 if (at24->flags & AT24_FLAG_ADDR16) { 308 i = *offset >> 16; 309 *offset &= 0xffff; 310 } else { 311 i = *offset >> 8; 312 *offset &= 0xff; 313 } 314 315 return at24->client_regmaps[i]; 316 } 317 318 static struct device *at24_base_client_dev(struct at24_data *at24) 319 { 320 return regmap_get_device(at24->client_regmaps[0]); 321 } 322 323 static size_t at24_adjust_read_count(struct at24_data *at24, 324 unsigned int offset, size_t count) 325 { 326 unsigned int bits; 327 size_t remainder; 328 329 /* 330 * In case of multi-address chips that don't rollover reads to 331 * the next slave address: truncate the count to the slave boundary, 332 * so that the read never straddles slaves. 333 */ 334 if (at24->flags & AT24_FLAG_NO_RDROL) { 335 bits = (at24->flags & AT24_FLAG_ADDR16) ? 16 : 8; 336 remainder = BIT(bits) - offset; 337 if (count > remainder) 338 count = remainder; 339 } 340 341 if (count > at24_io_limit) 342 count = at24_io_limit; 343 344 return count; 345 } 346 347 static ssize_t at24_regmap_read(struct at24_data *at24, char *buf, 348 unsigned int offset, size_t count) 349 { 350 unsigned long timeout, read_time; 351 struct regmap *regmap; 352 int ret; 353 354 regmap = at24_translate_offset(at24, &offset); 355 count = at24_adjust_read_count(at24, offset, count); 356 357 /* adjust offset for mac and serial read ops */ 358 offset += at24->offset_adj; 359 360 timeout = jiffies + msecs_to_jiffies(at24_write_timeout); 361 do { 362 /* 363 * The timestamp shall be taken before the actual operation 364 * to avoid a premature timeout in case of high CPU load. 365 */ 366 read_time = jiffies; 367 368 ret = regmap_bulk_read(regmap, offset, buf, count); 369 dev_dbg(regmap_get_device(regmap), "read %zu@%d --> %d (%ld)\n", 370 count, offset, ret, jiffies); 371 if (!ret) 372 return count; 373 374 usleep_range(1000, 1500); 375 } while (time_before(read_time, timeout)); 376 377 return -ETIMEDOUT; 378 } 379 380 /* 381 * Note that if the hardware write-protect pin is pulled high, the whole 382 * chip is normally write protected. But there are plenty of product 383 * variants here, including OTP fuses and partial chip protect. 384 * 385 * We only use page mode writes; the alternative is sloooow. These routines 386 * write at most one page. 387 */ 388 389 static size_t at24_adjust_write_count(struct at24_data *at24, 390 unsigned int offset, size_t count) 391 { 392 unsigned int next_page; 393 394 /* write_max is at most a page */ 395 if (count > at24->write_max) 396 count = at24->write_max; 397 398 /* Never roll over backwards, to the start of this page */ 399 next_page = roundup(offset + 1, at24->page_size); 400 if (offset + count > next_page) 401 count = next_page - offset; 402 403 return count; 404 } 405 406 static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf, 407 unsigned int offset, size_t count) 408 { 409 unsigned long timeout, write_time; 410 struct regmap *regmap; 411 int ret; 412 413 regmap = at24_translate_offset(at24, &offset); 414 count = at24_adjust_write_count(at24, offset, count); 415 timeout = jiffies + msecs_to_jiffies(at24_write_timeout); 416 417 do { 418 /* 419 * The timestamp shall be taken before the actual operation 420 * to avoid a premature timeout in case of high CPU load. 421 */ 422 write_time = jiffies; 423 424 ret = regmap_bulk_write(regmap, offset, buf, count); 425 dev_dbg(regmap_get_device(regmap), "write %zu@%d --> %d (%ld)\n", 426 count, offset, ret, jiffies); 427 if (!ret) 428 return count; 429 430 usleep_range(1000, 1500); 431 } while (time_before(write_time, timeout)); 432 433 return -ETIMEDOUT; 434 } 435 436 static int at24_read(void *priv, unsigned int off, void *val, size_t count) 437 { 438 struct at24_data *at24; 439 struct device *dev; 440 char *buf = val; 441 int i, ret; 442 443 at24 = priv; 444 dev = at24_base_client_dev(at24); 445 446 if (unlikely(!count)) 447 return count; 448 449 if (off + count > at24->byte_len) 450 return -EINVAL; 451 452 ret = pm_runtime_resume_and_get(dev); 453 if (ret) 454 return ret; 455 /* 456 * Read data from chip, protecting against concurrent updates 457 * from this host, but not from other I2C masters. 458 */ 459 mutex_lock(&at24->lock); 460 461 for (i = 0; count; i += ret, count -= ret) { 462 ret = at24_regmap_read(at24, buf + i, off + i, count); 463 if (ret < 0) { 464 mutex_unlock(&at24->lock); 465 pm_runtime_put(dev); 466 return ret; 467 } 468 } 469 470 mutex_unlock(&at24->lock); 471 472 pm_runtime_put(dev); 473 474 if (unlikely(at24->read_post)) 475 at24->read_post(off, buf, i); 476 477 return 0; 478 } 479 480 static int at24_write(void *priv, unsigned int off, void *val, size_t count) 481 { 482 struct at24_data *at24; 483 struct device *dev; 484 char *buf = val; 485 int ret; 486 487 at24 = priv; 488 dev = at24_base_client_dev(at24); 489 490 if (unlikely(!count)) 491 return -EINVAL; 492 493 if (off + count > at24->byte_len) 494 return -EINVAL; 495 496 ret = pm_runtime_resume_and_get(dev); 497 if (ret) 498 return ret; 499 /* 500 * Write data to chip, protecting against concurrent updates 501 * from this host, but not from other I2C masters. 502 */ 503 mutex_lock(&at24->lock); 504 505 while (count) { 506 ret = at24_regmap_write(at24, buf, off, count); 507 if (ret < 0) { 508 mutex_unlock(&at24->lock); 509 pm_runtime_put(dev); 510 return ret; 511 } 512 buf += ret; 513 off += ret; 514 count -= ret; 515 } 516 517 mutex_unlock(&at24->lock); 518 519 pm_runtime_put(dev); 520 521 return 0; 522 } 523 524 static int at24_make_dummy_client(struct at24_data *at24, unsigned int index, 525 struct i2c_client *base_client, 526 struct regmap_config *regmap_config) 527 { 528 struct i2c_client *dummy_client; 529 struct regmap *regmap; 530 531 dummy_client = devm_i2c_new_dummy_device(&base_client->dev, 532 base_client->adapter, 533 base_client->addr + 534 (index << at24->bank_addr_shift)); 535 if (IS_ERR(dummy_client)) 536 return PTR_ERR(dummy_client); 537 538 regmap = devm_regmap_init_i2c(dummy_client, regmap_config); 539 if (IS_ERR(regmap)) 540 return PTR_ERR(regmap); 541 542 at24->client_regmaps[index] = regmap; 543 544 return 0; 545 } 546 547 static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len) 548 { 549 if (flags & AT24_FLAG_MAC) { 550 /* EUI-48 starts from 0x9a, EUI-64 from 0x98 */ 551 return 0xa0 - byte_len; 552 } else if (flags & AT24_FLAG_SERIAL && flags & AT24_FLAG_ADDR16) { 553 /* 554 * For 16 bit address pointers, the word address must contain 555 * a '10' sequence in bits 11 and 10 regardless of the 556 * intended position of the address pointer. 557 */ 558 return 0x0800; 559 } else if (flags & AT24_FLAG_SERIAL) { 560 /* 561 * Otherwise the word address must begin with a '10' sequence, 562 * regardless of the intended address. 563 */ 564 return 0x0080; 565 } else { 566 return 0; 567 } 568 } 569 570 static void at24_probe_temp_sensor(struct i2c_client *client) 571 { 572 struct at24_data *at24 = i2c_get_clientdata(client); 573 struct i2c_board_info info = { .type = "jc42" }; 574 int ret; 575 u8 val; 576 577 /* 578 * Byte 2 has value 11 for DDR3, earlier versions don't 579 * support the thermal sensor present flag 580 */ 581 ret = at24_read(at24, 2, &val, 1); 582 if (ret || val != 11) 583 return; 584 585 /* Byte 32, bit 7 is set if temp sensor is present */ 586 ret = at24_read(at24, 32, &val, 1); 587 if (ret || !(val & BIT(7))) 588 return; 589 590 info.addr = 0x18 | (client->addr & 7); 591 592 i2c_new_client_device(client->adapter, &info); 593 } 594 595 static int at24_probe(struct i2c_client *client) 596 { 597 struct regmap_config regmap_config = { }; 598 struct nvmem_config nvmem_config = { }; 599 u32 byte_len, page_size, flags, addrw; 600 const struct at24_chip_data *cdata; 601 struct device *dev = &client->dev; 602 bool i2c_fn_i2c, i2c_fn_block; 603 unsigned int i, num_addresses; 604 struct at24_data *at24; 605 bool full_power; 606 struct regmap *regmap; 607 bool writable; 608 u8 test_byte; 609 int err; 610 611 i2c_fn_i2c = i2c_check_functionality(client->adapter, I2C_FUNC_I2C); 612 i2c_fn_block = i2c_check_functionality(client->adapter, 613 I2C_FUNC_SMBUS_WRITE_I2C_BLOCK); 614 615 cdata = i2c_get_match_data(client); 616 if (!cdata) 617 return -ENODEV; 618 619 err = device_property_read_u32(dev, "pagesize", &page_size); 620 if (err) 621 /* 622 * This is slow, but we can't know all eeproms, so we better 623 * play safe. Specifying custom eeprom-types via device tree 624 * or properties is recommended anyhow. 625 */ 626 page_size = 1; 627 628 flags = cdata->flags; 629 if (device_property_present(dev, "read-only")) 630 flags |= AT24_FLAG_READONLY; 631 if (device_property_present(dev, "no-read-rollover")) 632 flags |= AT24_FLAG_NO_RDROL; 633 634 err = device_property_read_u32(dev, "address-width", &addrw); 635 if (!err) { 636 switch (addrw) { 637 case 8: 638 if (flags & AT24_FLAG_ADDR16) 639 dev_warn(dev, 640 "Override address width to be 8, while default is 16\n"); 641 flags &= ~AT24_FLAG_ADDR16; 642 break; 643 case 16: 644 flags |= AT24_FLAG_ADDR16; 645 break; 646 default: 647 dev_warn(dev, "Bad \"address-width\" property: %u\n", 648 addrw); 649 } 650 } 651 652 err = device_property_read_u32(dev, "size", &byte_len); 653 if (err) 654 byte_len = cdata->byte_len; 655 656 if (!i2c_fn_i2c && !i2c_fn_block) 657 page_size = 1; 658 659 if (!page_size) 660 return dev_err_probe(dev, -EINVAL, "page_size must not be 0!\n"); 661 662 if (!is_power_of_2(page_size)) 663 dev_warn(dev, "page_size looks suspicious (no power of 2)!\n"); 664 665 err = device_property_read_u32(dev, "num-addresses", &num_addresses); 666 if (err) { 667 if (flags & AT24_FLAG_TAKE8ADDR) 668 num_addresses = 8; 669 else 670 num_addresses = DIV_ROUND_UP(byte_len, 671 (flags & AT24_FLAG_ADDR16) ? 65536 : 256); 672 } 673 674 if ((flags & AT24_FLAG_SERIAL) && (flags & AT24_FLAG_MAC)) 675 return dev_err_probe(dev, -EINVAL, 676 "invalid device data - cannot have both AT24_FLAG_SERIAL & AT24_FLAG_MAC."); 677 678 regmap_config.val_bits = 8; 679 regmap_config.reg_bits = (flags & AT24_FLAG_ADDR16) ? 16 : 8; 680 regmap_config.disable_locking = true; 681 682 regmap = devm_regmap_init_i2c(client, ®map_config); 683 if (IS_ERR(regmap)) 684 return PTR_ERR(regmap); 685 686 at24 = devm_kzalloc(dev, struct_size(at24, client_regmaps, num_addresses), 687 GFP_KERNEL); 688 if (!at24) 689 return -ENOMEM; 690 691 mutex_init(&at24->lock); 692 at24->byte_len = byte_len; 693 at24->page_size = page_size; 694 at24->flags = flags; 695 at24->read_post = cdata->read_post; 696 at24->bank_addr_shift = cdata->bank_addr_shift; 697 at24->num_addresses = num_addresses; 698 at24->offset_adj = at24_get_offset_adj(flags, byte_len); 699 at24->client_regmaps[0] = regmap; 700 701 at24->vcc_reg = devm_regulator_get(dev, "vcc"); 702 if (IS_ERR(at24->vcc_reg)) 703 return PTR_ERR(at24->vcc_reg); 704 705 writable = !(flags & AT24_FLAG_READONLY); 706 if (writable) { 707 at24->write_max = min_t(unsigned int, 708 page_size, at24_io_limit); 709 if (!i2c_fn_i2c && at24->write_max > I2C_SMBUS_BLOCK_MAX) 710 at24->write_max = I2C_SMBUS_BLOCK_MAX; 711 } 712 713 /* use dummy devices for multiple-address chips */ 714 for (i = 1; i < num_addresses; i++) { 715 err = at24_make_dummy_client(at24, i, client, ®map_config); 716 if (err) 717 return err; 718 } 719 720 /* 721 * We initialize nvmem_config.id to NVMEM_DEVID_AUTO even if the 722 * label property is set as some platform can have multiple eeproms 723 * with same label and we can not register each of those with same 724 * label. Failing to register those eeproms trigger cascade failure 725 * on such platform. 726 */ 727 nvmem_config.id = NVMEM_DEVID_AUTO; 728 729 if (device_property_present(dev, "label")) { 730 err = device_property_read_string(dev, "label", 731 &nvmem_config.name); 732 if (err) 733 return err; 734 } else { 735 nvmem_config.name = dev_name(dev); 736 } 737 738 nvmem_config.type = NVMEM_TYPE_EEPROM; 739 nvmem_config.dev = dev; 740 nvmem_config.read_only = !writable; 741 nvmem_config.root_only = !(flags & AT24_FLAG_IRUGO); 742 nvmem_config.owner = THIS_MODULE; 743 nvmem_config.compat = true; 744 nvmem_config.base_dev = dev; 745 nvmem_config.reg_read = at24_read; 746 nvmem_config.reg_write = at24_write; 747 nvmem_config.priv = at24; 748 nvmem_config.stride = 1; 749 nvmem_config.word_size = 1; 750 nvmem_config.size = byte_len; 751 752 i2c_set_clientdata(client, at24); 753 754 full_power = acpi_dev_state_d0(&client->dev); 755 if (full_power) { 756 err = regulator_enable(at24->vcc_reg); 757 if (err) 758 return dev_err_probe(dev, err, "Failed to enable vcc regulator\n"); 759 760 pm_runtime_set_active(dev); 761 } 762 pm_runtime_enable(dev); 763 764 /* 765 * Perform a one-byte test read to verify that the chip is functional, 766 * unless powering on the device is to be avoided during probe (i.e. 767 * it's powered off right now). 768 */ 769 if (full_power) { 770 err = at24_read(at24, 0, &test_byte, 1); 771 if (err) { 772 pm_runtime_disable(dev); 773 if (!pm_runtime_status_suspended(dev)) 774 regulator_disable(at24->vcc_reg); 775 return -ENODEV; 776 } 777 } 778 779 at24->nvmem = devm_nvmem_register(dev, &nvmem_config); 780 if (IS_ERR(at24->nvmem)) { 781 pm_runtime_disable(dev); 782 if (!pm_runtime_status_suspended(dev)) 783 regulator_disable(at24->vcc_reg); 784 return dev_err_probe(dev, PTR_ERR(at24->nvmem), 785 "failed to register nvmem\n"); 786 } 787 788 /* If this a SPD EEPROM, probe for DDR3 thermal sensor */ 789 if (cdata == &at24_data_spd) 790 at24_probe_temp_sensor(client); 791 792 pm_runtime_idle(dev); 793 794 if (writable) 795 dev_info(dev, "%u byte %s EEPROM, writable, %u bytes/write\n", 796 byte_len, client->name, at24->write_max); 797 else 798 dev_info(dev, "%u byte %s EEPROM, read-only\n", 799 byte_len, client->name); 800 801 return 0; 802 } 803 804 static void at24_remove(struct i2c_client *client) 805 { 806 struct at24_data *at24 = i2c_get_clientdata(client); 807 808 pm_runtime_disable(&client->dev); 809 if (acpi_dev_state_d0(&client->dev)) { 810 if (!pm_runtime_status_suspended(&client->dev)) 811 regulator_disable(at24->vcc_reg); 812 pm_runtime_set_suspended(&client->dev); 813 } 814 } 815 816 static int __maybe_unused at24_suspend(struct device *dev) 817 { 818 struct i2c_client *client = to_i2c_client(dev); 819 struct at24_data *at24 = i2c_get_clientdata(client); 820 821 return regulator_disable(at24->vcc_reg); 822 } 823 824 static int __maybe_unused at24_resume(struct device *dev) 825 { 826 struct i2c_client *client = to_i2c_client(dev); 827 struct at24_data *at24 = i2c_get_clientdata(client); 828 829 return regulator_enable(at24->vcc_reg); 830 } 831 832 static const struct dev_pm_ops at24_pm_ops = { 833 SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, 834 pm_runtime_force_resume) 835 SET_RUNTIME_PM_OPS(at24_suspend, at24_resume, NULL) 836 }; 837 838 static struct i2c_driver at24_driver = { 839 .driver = { 840 .name = "at24", 841 .pm = &at24_pm_ops, 842 .of_match_table = at24_of_match, 843 .acpi_match_table = at24_acpi_ids, 844 }, 845 .probe = at24_probe, 846 .remove = at24_remove, 847 .id_table = at24_ids, 848 .flags = I2C_DRV_ACPI_WAIVE_D0_PROBE, 849 }; 850 851 static int __init at24_init(void) 852 { 853 if (!at24_io_limit) { 854 pr_err("at24: at24_io_limit must not be 0!\n"); 855 return -EINVAL; 856 } 857 858 at24_io_limit = rounddown_pow_of_two(at24_io_limit); 859 return i2c_add_driver(&at24_driver); 860 } 861 module_init(at24_init); 862 863 static void __exit at24_exit(void) 864 { 865 i2c_del_driver(&at24_driver); 866 } 867 module_exit(at24_exit); 868 869 MODULE_DESCRIPTION("Driver for most I2C EEPROMs"); 870 MODULE_AUTHOR("David Brownell and Wolfram Sang"); 871 MODULE_LICENSE("GPL"); 872