1 // SPDX-License-Identifier: GPL-2.0-only
3 * Driver for 93xx46 EEPROMs
5 * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
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>
16 #include <linux/of_device.h>
17 #include <linux/slab.h>
18 #include <linux/spi/spi.h>
19 #include <linux/nvmem-provider.h>
20 #include <linux/eeprom_93xx46.h>
23 #define OP_WRITE (OP_START | 0x1)
24 #define OP_READ (OP_START | 0x2)
25 #define ADDR_EWDS 0x00
26 #define ADDR_ERAL 0x20
27 #define ADDR_EWEN 0x30
29 struct eeprom_93xx46_devtype_data {
34 static const struct eeprom_93xx46_devtype_data at93c46_data = {
38 static const struct eeprom_93xx46_devtype_data at93c56_data = {
42 static const struct eeprom_93xx46_devtype_data at93c66_data = {
46 static const struct eeprom_93xx46_devtype_data atmel_at93c46d_data = {
48 .quirks = EEPROM_93XX46_QUIRK_SINGLE_WORD_READ |
49 EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH,
52 static const struct eeprom_93xx46_devtype_data microchip_93lc46b_data = {
54 .quirks = EEPROM_93XX46_QUIRK_EXTRA_READ_CYCLE,
57 struct eeprom_93xx46_dev {
58 struct spi_device *spi;
59 struct eeprom_93xx46_platform_data *pdata;
61 struct nvmem_config nvmem_config;
62 struct nvmem_device *nvmem;
67 static inline bool has_quirk_single_word_read(struct eeprom_93xx46_dev *edev)
69 return edev->pdata->quirks & EEPROM_93XX46_QUIRK_SINGLE_WORD_READ;
72 static inline bool has_quirk_instruction_length(struct eeprom_93xx46_dev *edev)
74 return edev->pdata->quirks & EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH;
77 static inline bool has_quirk_extra_read_cycle(struct eeprom_93xx46_dev *edev)
79 return edev->pdata->quirks & EEPROM_93XX46_QUIRK_EXTRA_READ_CYCLE;
82 static int eeprom_93xx46_read(void *priv, unsigned int off,
83 void *val, size_t count)
85 struct eeprom_93xx46_dev *edev = priv;
90 if (unlikely(off >= edev->size))
92 if ((off + count) > edev->size)
93 count = edev->size - off;
97 mutex_lock(&edev->lock);
99 if (edev->pdata->prepare)
100 edev->pdata->prepare(edev);
102 /* The opcode in front of the address is three bits. */
103 bits = edev->addrlen + 3;
106 struct spi_message m;
107 struct spi_transfer t[2] = { { 0 } };
108 u16 cmd_addr = OP_READ << edev->addrlen;
109 size_t nbytes = count;
111 if (edev->pdata->flags & EE_ADDR8) {
113 if (has_quirk_single_word_read(edev))
116 cmd_addr |= (off >> 1);
117 if (has_quirk_single_word_read(edev))
121 dev_dbg(&edev->spi->dev, "read cmd 0x%x, %d Hz\n",
122 cmd_addr, edev->spi->max_speed_hz);
124 if (has_quirk_extra_read_cycle(edev)) {
129 spi_message_init(&m);
131 t[0].tx_buf = (char *)&cmd_addr;
133 t[0].bits_per_word = bits;
134 spi_message_add_tail(&t[0], &m);
138 t[1].bits_per_word = 8;
139 spi_message_add_tail(&t[1], &m);
141 err = spi_sync(edev->spi, &m);
142 /* have to wait at least Tcsl ns */
146 dev_err(&edev->spi->dev, "read %zu bytes at %d: err. %d\n",
147 nbytes, (int)off, err);
156 if (edev->pdata->finish)
157 edev->pdata->finish(edev);
159 mutex_unlock(&edev->lock);
164 static int eeprom_93xx46_ew(struct eeprom_93xx46_dev *edev, int is_on)
166 struct spi_message m;
167 struct spi_transfer t;
171 /* The opcode in front of the address is three bits. */
172 bits = edev->addrlen + 3;
174 cmd_addr = OP_START << edev->addrlen;
175 if (edev->pdata->flags & EE_ADDR8)
176 cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS) << 1;
178 cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS);
180 if (has_quirk_instruction_length(edev)) {
185 dev_dbg(&edev->spi->dev, "ew%s cmd 0x%04x, %d bits\n",
186 is_on ? "en" : "ds", cmd_addr, bits);
188 spi_message_init(&m);
189 memset(&t, 0, sizeof(t));
191 t.tx_buf = &cmd_addr;
193 t.bits_per_word = bits;
194 spi_message_add_tail(&t, &m);
196 mutex_lock(&edev->lock);
198 if (edev->pdata->prepare)
199 edev->pdata->prepare(edev);
201 ret = spi_sync(edev->spi, &m);
202 /* have to wait at least Tcsl ns */
205 dev_err(&edev->spi->dev, "erase/write %sable error %d\n",
206 is_on ? "en" : "dis", ret);
208 if (edev->pdata->finish)
209 edev->pdata->finish(edev);
211 mutex_unlock(&edev->lock);
216 eeprom_93xx46_write_word(struct eeprom_93xx46_dev *edev,
217 const char *buf, unsigned off)
219 struct spi_message m;
220 struct spi_transfer t[2];
221 int bits, data_len, ret;
224 if (unlikely(off >= edev->size))
227 /* The opcode in front of the address is three bits. */
228 bits = edev->addrlen + 3;
230 cmd_addr = OP_WRITE << edev->addrlen;
232 if (edev->pdata->flags & EE_ADDR8) {
236 cmd_addr |= (off >> 1);
240 dev_dbg(&edev->spi->dev, "write cmd 0x%x\n", cmd_addr);
242 spi_message_init(&m);
243 memset(t, 0, sizeof(t));
245 t[0].tx_buf = (char *)&cmd_addr;
247 t[0].bits_per_word = bits;
248 spi_message_add_tail(&t[0], &m);
252 t[1].bits_per_word = 8;
253 spi_message_add_tail(&t[1], &m);
255 ret = spi_sync(edev->spi, &m);
256 /* have to wait program cycle time Twc ms */
261 static int eeprom_93xx46_write(void *priv, unsigned int off,
262 void *val, size_t count)
264 struct eeprom_93xx46_dev *edev = priv;
266 int i, ret, step = 1;
268 if (unlikely(off >= edev->size))
270 if ((off + count) > edev->size)
271 count = edev->size - off;
272 if (unlikely(!count))
275 /* only write even number of bytes on 16-bit devices */
276 if (edev->pdata->flags & EE_ADDR16) {
281 /* erase/write enable */
282 ret = eeprom_93xx46_ew(edev, 1);
286 mutex_lock(&edev->lock);
288 if (edev->pdata->prepare)
289 edev->pdata->prepare(edev);
291 for (i = 0; i < count; i += step) {
292 ret = eeprom_93xx46_write_word(edev, &buf[i], off + i);
294 dev_err(&edev->spi->dev, "write failed at %d: %d\n",
300 if (edev->pdata->finish)
301 edev->pdata->finish(edev);
303 mutex_unlock(&edev->lock);
305 /* erase/write disable */
306 eeprom_93xx46_ew(edev, 0);
310 static int eeprom_93xx46_eral(struct eeprom_93xx46_dev *edev)
312 struct eeprom_93xx46_platform_data *pd = edev->pdata;
313 struct spi_message m;
314 struct spi_transfer t;
318 /* The opcode in front of the address is three bits. */
319 bits = edev->addrlen + 3;
321 cmd_addr = OP_START << edev->addrlen;
322 if (edev->pdata->flags & EE_ADDR8)
323 cmd_addr |= ADDR_ERAL << 1;
325 cmd_addr |= ADDR_ERAL;
327 if (has_quirk_instruction_length(edev)) {
332 dev_dbg(&edev->spi->dev, "eral cmd 0x%04x, %d bits\n", cmd_addr, bits);
334 spi_message_init(&m);
335 memset(&t, 0, sizeof(t));
337 t.tx_buf = &cmd_addr;
339 t.bits_per_word = bits;
340 spi_message_add_tail(&t, &m);
342 mutex_lock(&edev->lock);
344 if (edev->pdata->prepare)
345 edev->pdata->prepare(edev);
347 ret = spi_sync(edev->spi, &m);
349 dev_err(&edev->spi->dev, "erase error %d\n", ret);
350 /* have to wait erase cycle time Tec ms */
356 mutex_unlock(&edev->lock);
360 static ssize_t eeprom_93xx46_store_erase(struct device *dev,
361 struct device_attribute *attr,
362 const char *buf, size_t count)
364 struct eeprom_93xx46_dev *edev = dev_get_drvdata(dev);
367 sscanf(buf, "%d", &erase);
369 ret = eeprom_93xx46_ew(edev, 1);
372 ret = eeprom_93xx46_eral(edev);
375 ret = eeprom_93xx46_ew(edev, 0);
381 static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase);
383 static void select_assert(void *context)
385 struct eeprom_93xx46_dev *edev = context;
387 gpiod_set_value_cansleep(edev->pdata->select, 1);
390 static void select_deassert(void *context)
392 struct eeprom_93xx46_dev *edev = context;
394 gpiod_set_value_cansleep(edev->pdata->select, 0);
397 static const struct of_device_id eeprom_93xx46_of_table[] = {
398 { .compatible = "eeprom-93xx46", .data = &at93c46_data, },
399 { .compatible = "atmel,at93c46", .data = &at93c46_data, },
400 { .compatible = "atmel,at93c46d", .data = &atmel_at93c46d_data, },
401 { .compatible = "atmel,at93c56", .data = &at93c56_data, },
402 { .compatible = "atmel,at93c66", .data = &at93c66_data, },
403 { .compatible = "microchip,93lc46b", .data = µchip_93lc46b_data, },
406 MODULE_DEVICE_TABLE(of, eeprom_93xx46_of_table);
408 static const struct spi_device_id eeprom_93xx46_spi_ids[] = {
409 { .name = "eeprom-93xx46",
410 .driver_data = (kernel_ulong_t)&at93c46_data, },
412 .driver_data = (kernel_ulong_t)&at93c46_data, },
413 { .name = "at93c46d",
414 .driver_data = (kernel_ulong_t)&atmel_at93c46d_data, },
416 .driver_data = (kernel_ulong_t)&at93c56_data, },
418 .driver_data = (kernel_ulong_t)&at93c66_data, },
420 .driver_data = (kernel_ulong_t)µchip_93lc46b_data, },
423 MODULE_DEVICE_TABLE(spi, eeprom_93xx46_spi_ids);
425 static int eeprom_93xx46_probe_dt(struct spi_device *spi)
427 const struct of_device_id *of_id =
428 of_match_device(eeprom_93xx46_of_table, &spi->dev);
429 struct device_node *np = spi->dev.of_node;
430 struct eeprom_93xx46_platform_data *pd;
434 pd = devm_kzalloc(&spi->dev, sizeof(*pd), GFP_KERNEL);
438 ret = of_property_read_u32(np, "data-size", &tmp);
440 dev_err(&spi->dev, "data-size property not found\n");
445 pd->flags |= EE_ADDR8;
446 } else if (tmp == 16) {
447 pd->flags |= EE_ADDR16;
449 dev_err(&spi->dev, "invalid data-size (%d)\n", tmp);
453 if (of_property_read_bool(np, "read-only"))
454 pd->flags |= EE_READONLY;
456 pd->select = devm_gpiod_get_optional(&spi->dev, "select",
458 if (IS_ERR(pd->select))
459 return PTR_ERR(pd->select);
461 pd->prepare = select_assert;
462 pd->finish = select_deassert;
463 gpiod_direction_output(pd->select, 0);
466 const struct eeprom_93xx46_devtype_data *data = of_id->data;
468 pd->quirks = data->quirks;
469 pd->flags |= data->flags;
472 spi->dev.platform_data = pd;
477 static int eeprom_93xx46_probe(struct spi_device *spi)
479 struct eeprom_93xx46_platform_data *pd;
480 struct eeprom_93xx46_dev *edev;
483 if (spi->dev.of_node) {
484 err = eeprom_93xx46_probe_dt(spi);
489 pd = spi->dev.platform_data;
491 dev_err(&spi->dev, "missing platform data\n");
495 edev = devm_kzalloc(&spi->dev, sizeof(*edev), GFP_KERNEL);
499 if (pd->flags & EE_SIZE1K)
501 else if (pd->flags & EE_SIZE2K)
503 else if (pd->flags & EE_SIZE4K)
506 dev_err(&spi->dev, "unspecified size\n");
510 if (pd->flags & EE_ADDR8)
511 edev->addrlen = ilog2(edev->size);
512 else if (pd->flags & EE_ADDR16)
513 edev->addrlen = ilog2(edev->size) - 1;
515 dev_err(&spi->dev, "unspecified address type\n");
519 mutex_init(&edev->lock);
524 edev->nvmem_config.type = NVMEM_TYPE_EEPROM;
525 edev->nvmem_config.name = dev_name(&spi->dev);
526 edev->nvmem_config.dev = &spi->dev;
527 edev->nvmem_config.read_only = pd->flags & EE_READONLY;
528 edev->nvmem_config.root_only = true;
529 edev->nvmem_config.owner = THIS_MODULE;
530 edev->nvmem_config.compat = true;
531 edev->nvmem_config.base_dev = &spi->dev;
532 edev->nvmem_config.reg_read = eeprom_93xx46_read;
533 edev->nvmem_config.reg_write = eeprom_93xx46_write;
534 edev->nvmem_config.priv = edev;
535 edev->nvmem_config.stride = 4;
536 edev->nvmem_config.word_size = 1;
537 edev->nvmem_config.size = edev->size;
539 edev->nvmem = devm_nvmem_register(&spi->dev, &edev->nvmem_config);
540 if (IS_ERR(edev->nvmem))
541 return PTR_ERR(edev->nvmem);
543 dev_info(&spi->dev, "%d-bit eeprom containing %d bytes %s\n",
544 (pd->flags & EE_ADDR8) ? 8 : 16,
546 (pd->flags & EE_READONLY) ? "(readonly)" : "");
548 if (!(pd->flags & EE_READONLY)) {
549 if (device_create_file(&spi->dev, &dev_attr_erase))
550 dev_err(&spi->dev, "can't create erase interface\n");
553 spi_set_drvdata(spi, edev);
557 static void eeprom_93xx46_remove(struct spi_device *spi)
559 struct eeprom_93xx46_dev *edev = spi_get_drvdata(spi);
561 if (!(edev->pdata->flags & EE_READONLY))
562 device_remove_file(&spi->dev, &dev_attr_erase);
565 static struct spi_driver eeprom_93xx46_driver = {
568 .of_match_table = of_match_ptr(eeprom_93xx46_of_table),
570 .probe = eeprom_93xx46_probe,
571 .remove = eeprom_93xx46_remove,
572 .id_table = eeprom_93xx46_spi_ids,
575 module_spi_driver(eeprom_93xx46_driver);
577 MODULE_LICENSE("GPL");
578 MODULE_DESCRIPTION("Driver for 93xx46 EEPROMs");
579 MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>");
580 MODULE_ALIAS("spi:93xx46");
581 MODULE_ALIAS("spi:eeprom-93xx46");
582 MODULE_ALIAS("spi:93lc46b");