1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * at24.c - handle most I2C EEPROMs
5  * Copyright (C) 2005-2007 David Brownell
20 #include <linux/nvmem-provider.h>
30 /* sysfs-entry will be read-only. */
32 /* sysfs-entry will be world-readable. */
36 /* Factory-programmed serial number. */
38 /* Factory-programmed mac address. */
40 /* Does not auto-rollover reads to the next slave address. */
46  * MicroChip 24LC, etc) won't much matter for typical read/write access.
50  * However, misconfiguration can lose data. "Set 16-bit memory address"
51  * to a part with 8-bit addressing will overwrite data. Writing with too
56  * Accordingly, explicit board-specific configuration data should be used
61  * told what devices exist. That may be in arch/X/mach-Y/board-Z.c or
62  * similar kernel-resident tables; or, configuration data coming from
67  * It also handles larger devices (32 kbit and up) with two-byte addresses,
101  * clock, one 256 byte read takes about 1/43 second which is excessive;
152 	 * - BIOS passwords: bytes 0x00 to 0x0f  in at24_read_post_vaio()
153 	 * - UUID: bytes 0x10 to 0x1f  in at24_read_post_vaio()
154 	 * - Serial number: 0xc0 to 0xdf  in at24_read_post_vaio()
163 /* needs 8 addresses as A0-A2 are ignored */
186 /* 24rf08 quirk is handled at i2c-core */
217 	{ "24c02-vaio",	(kernel_ulong_t)&at24_data_24c02_vaio },
278  * Assumes that sanity checks for offset happened at sysfs-layer.
281  * set the byte address; on a multi-master board, another master
289 	if (at24->flags & AT24_FLAG_ADDR16) {  in at24_translate_offset()
297 	return at24->client_regmaps[i];  in at24_translate_offset()
302 	return regmap_get_device(at24->client_regmaps[0]);  in at24_base_client_dev()
312 	 * In case of multi-address chips that don't rollover reads to  in at24_adjust_read_count()
314 	 * so that the read never straddles slaves.  in at24_adjust_read_count()
316 	if (at24->flags & AT24_FLAG_NO_RDROL) {  in at24_adjust_read_count()
317 		bits = (at24->flags & AT24_FLAG_ADDR16) ? 16 : 8;  in at24_adjust_read_count()
318 		remainder = BIT(bits) - offset;  in at24_adjust_read_count()
339 	/* adjust offset for mac and serial read ops */  in at24_regmap_read()
340 	offset += at24->offset_adj;  in at24_regmap_read()
351 		dev_dbg(regmap_get_device(regmap), "read %zu@%d --> %d (%ld)\n",  in at24_regmap_read()
359 	return -ETIMEDOUT;  in at24_regmap_read()
363  * Note that if the hardware write-protect pin is pulled high, the whole
377 	if (count > at24->write_max)  in at24_adjust_write_count()
378 		count = at24->write_max;  in at24_adjust_write_count()
381 	next_page = roundup(offset + 1, at24->page_size);  in at24_adjust_write_count()
383 		count = next_page - offset;  in at24_adjust_write_count()
407 		dev_dbg(regmap_get_device(regmap), "write %zu@%d --> %d (%ld)\n",  in at24_regmap_write()
415 	return -ETIMEDOUT;  in at24_regmap_write()
431 	if (off + count > at24->byte_len)  in at24_read()
432 		return -EINVAL;  in at24_read()
441 	 * Read data from chip, protecting against concurrent updates  in at24_read()
444 	mutex_lock(&at24->lock);  in at24_read()
446 	for (i = 0; count; i += ret, count -= ret) {  in at24_read()
449 			mutex_unlock(&at24->lock);  in at24_read()
455 	mutex_unlock(&at24->lock);  in at24_read()
459 	if (unlikely(at24->read_post))  in at24_read()
460 		at24->read_post(off, buf, i);  in at24_read()
476 		return -EINVAL;  in at24_write()
478 	if (off + count > at24->byte_len)  in at24_write()
479 		return -EINVAL;  in at24_write()
491 	mutex_lock(&at24->lock);  in at24_write()
496 			mutex_unlock(&at24->lock);  in at24_write()
502 		count -= ret;  in at24_write()
505 	mutex_unlock(&at24->lock);  in at24_write()
514 	struct device_node *of_node = dev->of_node;  in at24_get_chip_data()
528 		cdata = (void *)id->driver_data;  in at24_get_chip_data()
533 		return ERR_PTR(-ENODEV);  in at24_get_chip_data()
545 	dummy_client = devm_i2c_new_dummy_device(&base_client->dev,  in at24_make_dummy_client()
546 						 base_client->adapter,  in at24_make_dummy_client()
547 						 base_client->addr +  in at24_make_dummy_client()
548 						 (index << at24->bank_addr_shift));  in at24_make_dummy_client()
556 	at24->client_regmaps[index] = regmap;  in at24_make_dummy_client()
564 		/* EUI-48 starts from 0x9a, EUI-64 from 0x98 */  in at24_get_offset_adj()
565 		return 0xa0 - byte_len;  in at24_get_offset_adj()
590 	struct device *dev = &client->dev;  in at24_probe()
600 	i2c_fn_i2c = i2c_check_functionality(client->adapter, I2C_FUNC_I2C);  in at24_probe()
601 	i2c_fn_block = i2c_check_functionality(client->adapter,  in at24_probe()
612 		 * play safe. Specifying custom eeprom-types via device tree  in at24_probe()
617 	flags = cdata->flags;  in at24_probe()
618 	if (device_property_present(dev, "read-only"))  in at24_probe()
620 	if (device_property_present(dev, "no-read-rollover"))  in at24_probe()
623 	err = device_property_read_u32(dev, "address-width", &addrw);  in at24_probe()
636 			dev_warn(dev, "Bad \"address-width\" property: %u\n",  in at24_probe()
643 		byte_len = cdata->byte_len;  in at24_probe()
650 		return -EINVAL;  in at24_probe()
654 		dev_warn(dev, "page_size looks suspicious (no power of 2)!\n");  in at24_probe()
656 	err = device_property_read_u32(dev, "num-addresses", &num_addresses);  in at24_probe()
667 			"invalid device data - cannot have both AT24_FLAG_SERIAL & AT24_FLAG_MAC.");  in at24_probe()
668 		return -EINVAL;  in at24_probe()
682 		return -ENOMEM;  in at24_probe()
684 	mutex_init(&at24->lock);  in at24_probe()
685 	at24->byte_len = byte_len;  in at24_probe()
686 	at24->page_size = page_size;  in at24_probe()
687 	at24->flags = flags;  in at24_probe()
688 	at24->read_post = cdata->read_post;  in at24_probe()
689 	at24->bank_addr_shift = cdata->bank_addr_shift;  in at24_probe()
690 	at24->num_addresses = num_addresses;  in at24_probe()
691 	at24->offset_adj = at24_get_offset_adj(flags, byte_len);  in at24_probe()
692 	at24->client_regmaps[0] = regmap;  in at24_probe()
694 	at24->vcc_reg = devm_regulator_get(dev, "vcc");  in at24_probe()
695 	if (IS_ERR(at24->vcc_reg))  in at24_probe()
696 		return PTR_ERR(at24->vcc_reg);  in at24_probe()
700 		at24->write_max = min_t(unsigned int,  in at24_probe()
702 		if (!i2c_fn_i2c && at24->write_max > I2C_SMBUS_BLOCK_MAX)  in at24_probe()
703 			at24->write_max = I2C_SMBUS_BLOCK_MAX;  in at24_probe()
706 	/* use dummy devices for multiple-address chips */  in at24_probe()
747 	full_power = acpi_dev_state_d0(&client->dev);  in at24_probe()
749 		err = regulator_enable(at24->vcc_reg);  in at24_probe()
759 	at24->nvmem = devm_nvmem_register(dev, &nvmem_config);  in at24_probe()
760 	if (IS_ERR(at24->nvmem)) {  in at24_probe()
763 			regulator_disable(at24->vcc_reg);  in at24_probe()
764 		return PTR_ERR(at24->nvmem);  in at24_probe()
768 	 * Perform a one-byte test read to verify that the chip is functional,  in at24_probe()
777 				regulator_disable(at24->vcc_reg);  in at24_probe()
778 			return -ENODEV;  in at24_probe()
786 			 byte_len, client->name, at24->write_max);  in at24_probe()
788 		dev_info(dev, "%u byte %s EEPROM, read-only\n",  in at24_probe()
789 			 byte_len, client->name);  in at24_probe()
798 	pm_runtime_disable(&client->dev);  in at24_remove()
799 	if (acpi_dev_state_d0(&client->dev)) {  in at24_remove()
800 		if (!pm_runtime_status_suspended(&client->dev))  in at24_remove()
801 			regulator_disable(at24->vcc_reg);  in at24_remove()
802 		pm_runtime_set_suspended(&client->dev);  in at24_remove()
811 	return regulator_disable(at24->vcc_reg);  in at24_suspend()
819 	return regulator_enable(at24->vcc_reg);  in at24_resume()
845 		return -EINVAL;  in at24_init()