1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Driver for 93xx46 EEPROMs 4 * 5 * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de> 6 */ 7 8 #include <linux/delay.h> 9 #include <linux/device.h> 10 #include <linux/gpio/consumer.h> 11 #include <linux/kernel.h> 12 #include <linux/log2.h> 13 #include <linux/module.h> 14 #include <linux/mutex.h> 15 #include <linux/of.h> 16 #include <linux/of_device.h> 17 #include <linux/of_gpio.h> 18 #include <linux/slab.h> 19 #include <linux/spi/spi.h> 20 #include <linux/nvmem-provider.h> 21 #include <linux/eeprom_93xx46.h> 22 23 #define OP_START 0x4 24 #define OP_WRITE (OP_START | 0x1) 25 #define OP_READ (OP_START | 0x2) 26 #define ADDR_EWDS 0x00 27 #define ADDR_ERAL 0x20 28 #define ADDR_EWEN 0x30 29 30 struct eeprom_93xx46_devtype_data { 31 unsigned int quirks; 32 unsigned char flags; 33 }; 34 35 static const struct eeprom_93xx46_devtype_data at93c46_data = { 36 .flags = EE_SIZE1K, 37 }; 38 39 static const struct eeprom_93xx46_devtype_data at93c56_data = { 40 .flags = EE_SIZE2K, 41 }; 42 43 static const struct eeprom_93xx46_devtype_data at93c66_data = { 44 .flags = EE_SIZE4K, 45 }; 46 47 static const struct eeprom_93xx46_devtype_data atmel_at93c46d_data = { 48 .flags = EE_SIZE1K, 49 .quirks = EEPROM_93XX46_QUIRK_SINGLE_WORD_READ | 50 EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH, 51 }; 52 53 static const struct eeprom_93xx46_devtype_data microchip_93lc46b_data = { 54 .flags = EE_SIZE1K, 55 .quirks = EEPROM_93XX46_QUIRK_EXTRA_READ_CYCLE, 56 }; 57 58 struct eeprom_93xx46_dev { 59 struct spi_device *spi; 60 struct eeprom_93xx46_platform_data *pdata; 61 struct mutex lock; 62 struct nvmem_config nvmem_config; 63 struct nvmem_device *nvmem; 64 int addrlen; 65 int size; 66 }; 67 68 static inline bool has_quirk_single_word_read(struct eeprom_93xx46_dev *edev) 69 { 70 return edev->pdata->quirks & EEPROM_93XX46_QUIRK_SINGLE_WORD_READ; 71 } 72 73 static inline bool has_quirk_instruction_length(struct eeprom_93xx46_dev *edev) 74 { 75 return edev->pdata->quirks & EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH; 76 } 77 78 static inline bool has_quirk_extra_read_cycle(struct eeprom_93xx46_dev *edev) 79 { 80 return edev->pdata->quirks & EEPROM_93XX46_QUIRK_EXTRA_READ_CYCLE; 81 } 82 83 static int eeprom_93xx46_read(void *priv, unsigned int off, 84 void *val, size_t count) 85 { 86 struct eeprom_93xx46_dev *edev = priv; 87 char *buf = val; 88 int err = 0; 89 int bits; 90 91 if (unlikely(off >= edev->size)) 92 return 0; 93 if ((off + count) > edev->size) 94 count = edev->size - off; 95 if (unlikely(!count)) 96 return count; 97 98 mutex_lock(&edev->lock); 99 100 if (edev->pdata->prepare) 101 edev->pdata->prepare(edev); 102 103 /* The opcode in front of the address is three bits. */ 104 bits = edev->addrlen + 3; 105 106 while (count) { 107 struct spi_message m; 108 struct spi_transfer t[2] = { { 0 } }; 109 u16 cmd_addr = OP_READ << edev->addrlen; 110 size_t nbytes = count; 111 112 if (edev->pdata->flags & EE_ADDR8) { 113 cmd_addr |= off; 114 if (has_quirk_single_word_read(edev)) 115 nbytes = 1; 116 } else { 117 cmd_addr |= (off >> 1); 118 if (has_quirk_single_word_read(edev)) 119 nbytes = 2; 120 } 121 122 dev_dbg(&edev->spi->dev, "read cmd 0x%x, %d Hz\n", 123 cmd_addr, edev->spi->max_speed_hz); 124 125 if (has_quirk_extra_read_cycle(edev)) { 126 cmd_addr <<= 1; 127 bits += 1; 128 } 129 130 spi_message_init(&m); 131 132 t[0].tx_buf = (char *)&cmd_addr; 133 t[0].len = 2; 134 t[0].bits_per_word = bits; 135 spi_message_add_tail(&t[0], &m); 136 137 t[1].rx_buf = buf; 138 t[1].len = count; 139 t[1].bits_per_word = 8; 140 spi_message_add_tail(&t[1], &m); 141 142 err = spi_sync(edev->spi, &m); 143 /* have to wait at least Tcsl ns */ 144 ndelay(250); 145 146 if (err) { 147 dev_err(&edev->spi->dev, "read %zu bytes at %d: err. %d\n", 148 nbytes, (int)off, err); 149 break; 150 } 151 152 buf += nbytes; 153 off += nbytes; 154 count -= nbytes; 155 } 156 157 if (edev->pdata->finish) 158 edev->pdata->finish(edev); 159 160 mutex_unlock(&edev->lock); 161 162 return err; 163 } 164 165 static int eeprom_93xx46_ew(struct eeprom_93xx46_dev *edev, int is_on) 166 { 167 struct spi_message m; 168 struct spi_transfer t; 169 int bits, ret; 170 u16 cmd_addr; 171 172 /* The opcode in front of the address is three bits. */ 173 bits = edev->addrlen + 3; 174 175 cmd_addr = OP_START << edev->addrlen; 176 if (edev->pdata->flags & EE_ADDR8) 177 cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS) << 1; 178 else 179 cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS); 180 181 if (has_quirk_instruction_length(edev)) { 182 cmd_addr <<= 2; 183 bits += 2; 184 } 185 186 dev_dbg(&edev->spi->dev, "ew%s cmd 0x%04x, %d bits\n", 187 is_on ? "en" : "ds", cmd_addr, bits); 188 189 spi_message_init(&m); 190 memset(&t, 0, sizeof(t)); 191 192 t.tx_buf = &cmd_addr; 193 t.len = 2; 194 t.bits_per_word = bits; 195 spi_message_add_tail(&t, &m); 196 197 mutex_lock(&edev->lock); 198 199 if (edev->pdata->prepare) 200 edev->pdata->prepare(edev); 201 202 ret = spi_sync(edev->spi, &m); 203 /* have to wait at least Tcsl ns */ 204 ndelay(250); 205 if (ret) 206 dev_err(&edev->spi->dev, "erase/write %sable error %d\n", 207 is_on ? "en" : "dis", ret); 208 209 if (edev->pdata->finish) 210 edev->pdata->finish(edev); 211 212 mutex_unlock(&edev->lock); 213 return ret; 214 } 215 216 static ssize_t 217 eeprom_93xx46_write_word(struct eeprom_93xx46_dev *edev, 218 const char *buf, unsigned off) 219 { 220 struct spi_message m; 221 struct spi_transfer t[2]; 222 int bits, data_len, ret; 223 u16 cmd_addr; 224 225 if (unlikely(off >= edev->size)) 226 return -EINVAL; 227 228 /* The opcode in front of the address is three bits. */ 229 bits = edev->addrlen + 3; 230 231 cmd_addr = OP_WRITE << edev->addrlen; 232 233 if (edev->pdata->flags & EE_ADDR8) { 234 cmd_addr |= off; 235 data_len = 1; 236 } else { 237 cmd_addr |= (off >> 1); 238 data_len = 2; 239 } 240 241 dev_dbg(&edev->spi->dev, "write cmd 0x%x\n", cmd_addr); 242 243 spi_message_init(&m); 244 memset(t, 0, sizeof(t)); 245 246 t[0].tx_buf = (char *)&cmd_addr; 247 t[0].len = 2; 248 t[0].bits_per_word = bits; 249 spi_message_add_tail(&t[0], &m); 250 251 t[1].tx_buf = buf; 252 t[1].len = data_len; 253 t[1].bits_per_word = 8; 254 spi_message_add_tail(&t[1], &m); 255 256 ret = spi_sync(edev->spi, &m); 257 /* have to wait program cycle time Twc ms */ 258 mdelay(6); 259 return ret; 260 } 261 262 static int eeprom_93xx46_write(void *priv, unsigned int off, 263 void *val, size_t count) 264 { 265 struct eeprom_93xx46_dev *edev = priv; 266 char *buf = val; 267 int i, ret, step = 1; 268 269 if (unlikely(off >= edev->size)) 270 return -EFBIG; 271 if ((off + count) > edev->size) 272 count = edev->size - off; 273 if (unlikely(!count)) 274 return count; 275 276 /* only write even number of bytes on 16-bit devices */ 277 if (edev->pdata->flags & EE_ADDR16) { 278 step = 2; 279 count &= ~1; 280 } 281 282 /* erase/write enable */ 283 ret = eeprom_93xx46_ew(edev, 1); 284 if (ret) 285 return ret; 286 287 mutex_lock(&edev->lock); 288 289 if (edev->pdata->prepare) 290 edev->pdata->prepare(edev); 291 292 for (i = 0; i < count; i += step) { 293 ret = eeprom_93xx46_write_word(edev, &buf[i], off + i); 294 if (ret) { 295 dev_err(&edev->spi->dev, "write failed at %d: %d\n", 296 (int)off + i, ret); 297 break; 298 } 299 } 300 301 if (edev->pdata->finish) 302 edev->pdata->finish(edev); 303 304 mutex_unlock(&edev->lock); 305 306 /* erase/write disable */ 307 eeprom_93xx46_ew(edev, 0); 308 return ret; 309 } 310 311 static int eeprom_93xx46_eral(struct eeprom_93xx46_dev *edev) 312 { 313 struct eeprom_93xx46_platform_data *pd = edev->pdata; 314 struct spi_message m; 315 struct spi_transfer t; 316 int bits, ret; 317 u16 cmd_addr; 318 319 /* The opcode in front of the address is three bits. */ 320 bits = edev->addrlen + 3; 321 322 cmd_addr = OP_START << edev->addrlen; 323 if (edev->pdata->flags & EE_ADDR8) 324 cmd_addr |= ADDR_ERAL << 1; 325 else 326 cmd_addr |= ADDR_ERAL; 327 328 if (has_quirk_instruction_length(edev)) { 329 cmd_addr <<= 2; 330 bits += 2; 331 } 332 333 dev_dbg(&edev->spi->dev, "eral cmd 0x%04x, %d bits\n", cmd_addr, bits); 334 335 spi_message_init(&m); 336 memset(&t, 0, sizeof(t)); 337 338 t.tx_buf = &cmd_addr; 339 t.len = 2; 340 t.bits_per_word = bits; 341 spi_message_add_tail(&t, &m); 342 343 mutex_lock(&edev->lock); 344 345 if (edev->pdata->prepare) 346 edev->pdata->prepare(edev); 347 348 ret = spi_sync(edev->spi, &m); 349 if (ret) 350 dev_err(&edev->spi->dev, "erase error %d\n", ret); 351 /* have to wait erase cycle time Tec ms */ 352 mdelay(6); 353 354 if (pd->finish) 355 pd->finish(edev); 356 357 mutex_unlock(&edev->lock); 358 return ret; 359 } 360 361 static ssize_t eeprom_93xx46_store_erase(struct device *dev, 362 struct device_attribute *attr, 363 const char *buf, size_t count) 364 { 365 struct eeprom_93xx46_dev *edev = dev_get_drvdata(dev); 366 int erase = 0, ret; 367 368 sscanf(buf, "%d", &erase); 369 if (erase) { 370 ret = eeprom_93xx46_ew(edev, 1); 371 if (ret) 372 return ret; 373 ret = eeprom_93xx46_eral(edev); 374 if (ret) 375 return ret; 376 ret = eeprom_93xx46_ew(edev, 0); 377 if (ret) 378 return ret; 379 } 380 return count; 381 } 382 static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase); 383 384 static void select_assert(void *context) 385 { 386 struct eeprom_93xx46_dev *edev = context; 387 388 gpiod_set_value_cansleep(edev->pdata->select, 1); 389 } 390 391 static void select_deassert(void *context) 392 { 393 struct eeprom_93xx46_dev *edev = context; 394 395 gpiod_set_value_cansleep(edev->pdata->select, 0); 396 } 397 398 static const struct of_device_id eeprom_93xx46_of_table[] = { 399 { .compatible = "eeprom-93xx46", .data = &at93c46_data, }, 400 { .compatible = "atmel,at93c46", .data = &at93c46_data, }, 401 { .compatible = "atmel,at93c46d", .data = &atmel_at93c46d_data, }, 402 { .compatible = "atmel,at93c56", .data = &at93c56_data, }, 403 { .compatible = "atmel,at93c66", .data = &at93c66_data, }, 404 { .compatible = "microchip,93lc46b", .data = µchip_93lc46b_data, }, 405 {} 406 }; 407 MODULE_DEVICE_TABLE(of, eeprom_93xx46_of_table); 408 409 static int eeprom_93xx46_probe_dt(struct spi_device *spi) 410 { 411 const struct of_device_id *of_id = 412 of_match_device(eeprom_93xx46_of_table, &spi->dev); 413 struct device_node *np = spi->dev.of_node; 414 struct eeprom_93xx46_platform_data *pd; 415 u32 tmp; 416 int ret; 417 418 pd = devm_kzalloc(&spi->dev, sizeof(*pd), GFP_KERNEL); 419 if (!pd) 420 return -ENOMEM; 421 422 ret = of_property_read_u32(np, "data-size", &tmp); 423 if (ret < 0) { 424 dev_err(&spi->dev, "data-size property not found\n"); 425 return ret; 426 } 427 428 if (tmp == 8) { 429 pd->flags |= EE_ADDR8; 430 } else if (tmp == 16) { 431 pd->flags |= EE_ADDR16; 432 } else { 433 dev_err(&spi->dev, "invalid data-size (%d)\n", tmp); 434 return -EINVAL; 435 } 436 437 if (of_property_read_bool(np, "read-only")) 438 pd->flags |= EE_READONLY; 439 440 pd->select = devm_gpiod_get_optional(&spi->dev, "select", 441 GPIOD_OUT_LOW); 442 if (IS_ERR(pd->select)) 443 return PTR_ERR(pd->select); 444 445 pd->prepare = select_assert; 446 pd->finish = select_deassert; 447 gpiod_direction_output(pd->select, 0); 448 449 if (of_id->data) { 450 const struct eeprom_93xx46_devtype_data *data = of_id->data; 451 452 pd->quirks = data->quirks; 453 pd->flags |= data->flags; 454 } 455 456 spi->dev.platform_data = pd; 457 458 return 0; 459 } 460 461 static int eeprom_93xx46_probe(struct spi_device *spi) 462 { 463 struct eeprom_93xx46_platform_data *pd; 464 struct eeprom_93xx46_dev *edev; 465 int err; 466 467 if (spi->dev.of_node) { 468 err = eeprom_93xx46_probe_dt(spi); 469 if (err < 0) 470 return err; 471 } 472 473 pd = spi->dev.platform_data; 474 if (!pd) { 475 dev_err(&spi->dev, "missing platform data\n"); 476 return -ENODEV; 477 } 478 479 edev = devm_kzalloc(&spi->dev, sizeof(*edev), GFP_KERNEL); 480 if (!edev) 481 return -ENOMEM; 482 483 if (pd->flags & EE_SIZE1K) 484 edev->size = 128; 485 else if (pd->flags & EE_SIZE2K) 486 edev->size = 256; 487 else if (pd->flags & EE_SIZE4K) 488 edev->size = 512; 489 else { 490 dev_err(&spi->dev, "unspecified size\n"); 491 return -EINVAL; 492 } 493 494 if (pd->flags & EE_ADDR8) 495 edev->addrlen = ilog2(edev->size); 496 else if (pd->flags & EE_ADDR16) 497 edev->addrlen = ilog2(edev->size) - 1; 498 else { 499 dev_err(&spi->dev, "unspecified address type\n"); 500 return -EINVAL; 501 } 502 503 mutex_init(&edev->lock); 504 505 edev->spi = spi; 506 edev->pdata = pd; 507 508 edev->nvmem_config.type = NVMEM_TYPE_EEPROM; 509 edev->nvmem_config.name = dev_name(&spi->dev); 510 edev->nvmem_config.dev = &spi->dev; 511 edev->nvmem_config.read_only = pd->flags & EE_READONLY; 512 edev->nvmem_config.root_only = true; 513 edev->nvmem_config.owner = THIS_MODULE; 514 edev->nvmem_config.compat = true; 515 edev->nvmem_config.base_dev = &spi->dev; 516 edev->nvmem_config.reg_read = eeprom_93xx46_read; 517 edev->nvmem_config.reg_write = eeprom_93xx46_write; 518 edev->nvmem_config.priv = edev; 519 edev->nvmem_config.stride = 4; 520 edev->nvmem_config.word_size = 1; 521 edev->nvmem_config.size = edev->size; 522 523 edev->nvmem = devm_nvmem_register(&spi->dev, &edev->nvmem_config); 524 if (IS_ERR(edev->nvmem)) 525 return PTR_ERR(edev->nvmem); 526 527 dev_info(&spi->dev, "%d-bit eeprom containing %d bytes %s\n", 528 (pd->flags & EE_ADDR8) ? 8 : 16, 529 edev->size, 530 (pd->flags & EE_READONLY) ? "(readonly)" : ""); 531 532 if (!(pd->flags & EE_READONLY)) { 533 if (device_create_file(&spi->dev, &dev_attr_erase)) 534 dev_err(&spi->dev, "can't create erase interface\n"); 535 } 536 537 spi_set_drvdata(spi, edev); 538 return 0; 539 } 540 541 static int eeprom_93xx46_remove(struct spi_device *spi) 542 { 543 struct eeprom_93xx46_dev *edev = spi_get_drvdata(spi); 544 545 if (!(edev->pdata->flags & EE_READONLY)) 546 device_remove_file(&spi->dev, &dev_attr_erase); 547 548 return 0; 549 } 550 551 static struct spi_driver eeprom_93xx46_driver = { 552 .driver = { 553 .name = "93xx46", 554 .of_match_table = of_match_ptr(eeprom_93xx46_of_table), 555 }, 556 .probe = eeprom_93xx46_probe, 557 .remove = eeprom_93xx46_remove, 558 }; 559 560 module_spi_driver(eeprom_93xx46_driver); 561 562 MODULE_LICENSE("GPL"); 563 MODULE_DESCRIPTION("Driver for 93xx46 EEPROMs"); 564 MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>"); 565 MODULE_ALIAS("spi:93xx46"); 566 MODULE_ALIAS("spi:eeprom-93xx46"); 567 MODULE_ALIAS("spi:93lc46b"); 568