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>
31 /* sysfs-entry will be read-only. */
33 /* sysfs-entry will be world-readable. */
37 /* Factory-programmed serial number. */
39 /* Factory-programmed mac address. */
41 /* Does not auto-rollover reads to the next slave address. */
47  * MicroChip 24LC, etc) won't much matter for typical read/write access.
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
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.)
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
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,
153 	 * - BIOS passwords: bytes 0x00 to 0x0f  in at24_read_post_vaio()
154 	 * - UUID: bytes 0x10 to 0x1f  in at24_read_post_vaio()
155 	 * - Serial number: 0xc0 to 0xdf  in at24_read_post_vaio()
164 /* needs 8 addresses as A0-A2 are ignored */
191 /* 24rf08 quirk is handled at i2c-core */
199 /* M24C32-D Additional Write lockable page (M24C32-D order codes) */
204 /* M24C64-D Additional Write lockable page (M24C64-D order codes) */
210 /* M24256E Additional Write lockable page (M24256E-F order codes) */
230 	{ "24c02-vaio",	(kernel_ulong_t)&at24_data_24c02_vaio },
238 	{ "24c32d-wl",	(kernel_ulong_t)&at24_data_24c32d_wlp },
241 	{ "24c64-wl",	(kernel_ulong_t)&at24_data_24c64d_wlp },
245 	{ "24256e-wl",	(kernel_ulong_t)&at24_data_24256e_wlp },
271 	{ .compatible = "atmel,24c32d-wl",	.data = &at24_data_24c32d_wlp },
274 	{ .compatible = "atmel,24c64d-wl",	.data = &at24_data_24c64d_wlp },
284 	{ .compatible = "st,24256e-wl",		.data = &at24_data_24256e_wlp },
299  * Assumes that sanity checks for offset happened at sysfs-layer.
302  * set the byte address; on a multi-master board, another master
310 	if (at24->flags & AT24_FLAG_ADDR16) {  in at24_translate_offset()
318 	return at24->client_regmaps[i];  in at24_translate_offset()
323 	return regmap_get_device(at24->client_regmaps[0]);  in at24_base_client_dev()
333 	 * In case of multi-address chips that don't rollover reads to  in at24_adjust_read_count()
337 	if (at24->flags & AT24_FLAG_NO_RDROL) {  in at24_adjust_read_count()
338 		bits = (at24->flags & AT24_FLAG_ADDR16) ? 16 : 8;  in at24_adjust_read_count()
339 		remainder = BIT(bits) - offset;  in at24_adjust_read_count()
361 	offset += at24->offset_adj;  in at24_regmap_read()
372 		dev_dbg(regmap_get_device(regmap), "read %zu@%d --> %d (%ld)\n",  in at24_regmap_read()
380 	return -ETIMEDOUT;  in at24_regmap_read()
384  * Note that if the hardware write-protect pin is pulled high, the whole
398 	if (count > at24->write_max)  in at24_adjust_write_count()
399 		count = at24->write_max;  in at24_adjust_write_count()
402 	next_page = roundup(offset + 1, at24->page_size);  in at24_adjust_write_count()
404 		count = next_page - offset;  in at24_adjust_write_count()
428 		dev_dbg(regmap_get_device(regmap), "write %zu@%d --> %d (%ld)\n",  in at24_regmap_write()
436 	return -ETIMEDOUT;  in at24_regmap_write()
452 	if (off + count > at24->byte_len)  in at24_read()
453 		return -EINVAL;  in at24_read()
462 	mutex_lock(&at24->lock);  in at24_read()
464 	for (i = 0; count; i += ret, count -= ret) {  in at24_read()
467 			mutex_unlock(&at24->lock);  in at24_read()
473 	mutex_unlock(&at24->lock);  in at24_read()
477 	if (unlikely(at24->read_post))  in at24_read()
478 		at24->read_post(off, buf, i);  in at24_read()
494 		return -EINVAL;  in at24_write()
496 	if (off + count > at24->byte_len)  in at24_write()
497 		return -EINVAL;  in at24_write()
506 	mutex_lock(&at24->lock);  in at24_write()
511 			mutex_unlock(&at24->lock);  in at24_write()
517 		count -= ret;  in at24_write()
520 	mutex_unlock(&at24->lock);  in at24_write()
534 	dummy_client = devm_i2c_new_dummy_device(&base_client->dev,  in at24_make_dummy_client()
535 						 base_client->adapter,  in at24_make_dummy_client()
536 						 base_client->addr +  in at24_make_dummy_client()
537 						 (index << at24->bank_addr_shift));  in at24_make_dummy_client()
545 	at24->client_regmaps[index] = regmap;  in at24_make_dummy_client()
553 		/* EUI-48 starts from 0x9a, EUI-64 from 0x98 */  in at24_get_offset_adj()
554 		return 0xa0 - byte_len;  in at24_get_offset_adj()
593 	info.addr = 0x18 | (client->addr & 7);  in at24_probe_temp_sensor()
595 	i2c_new_client_device(client->adapter, &info);  in at24_probe_temp_sensor()
604 	struct device *dev = &client->dev;  in at24_probe()
614 	i2c_fn_i2c = i2c_check_functionality(client->adapter, I2C_FUNC_I2C);  in at24_probe()
615 	i2c_fn_block = i2c_check_functionality(client->adapter,  in at24_probe()
620 		return -ENODEV;  in at24_probe()
626 		 * play safe. Specifying custom eeprom-types via device tree  in at24_probe()
631 	flags = cdata->flags;  in at24_probe()
632 	if (device_property_present(dev, "read-only"))  in at24_probe()
634 	if (device_property_present(dev, "no-read-rollover"))  in at24_probe()
637 	err = device_property_read_u32(dev, "address-width", &addrw);  in at24_probe()
650 			dev_warn(dev, "Bad \"address-width\" property: %u\n",  in at24_probe()
657 		byte_len = cdata->byte_len;  in at24_probe()
664 		return -EINVAL;  in at24_probe()
670 	err = device_property_read_u32(dev, "num-addresses", &num_addresses);  in at24_probe()
681 			"invalid device data - cannot have both AT24_FLAG_SERIAL & AT24_FLAG_MAC.");  in at24_probe()
682 		return -EINVAL;  in at24_probe()
696 		return -ENOMEM;  in at24_probe()
698 	mutex_init(&at24->lock);  in at24_probe()
699 	at24->byte_len = byte_len;  in at24_probe()
700 	at24->page_size = page_size;  in at24_probe()
701 	at24->flags = flags;  in at24_probe()
702 	at24->read_post = cdata->read_post;  in at24_probe()
703 	at24->bank_addr_shift = cdata->bank_addr_shift;  in at24_probe()
704 	at24->num_addresses = num_addresses;  in at24_probe()
705 	at24->offset_adj = at24_get_offset_adj(flags, byte_len);  in at24_probe()
706 	at24->client_regmaps[0] = regmap;  in at24_probe()
708 	at24->vcc_reg = devm_regulator_get(dev, "vcc");  in at24_probe()
709 	if (IS_ERR(at24->vcc_reg))  in at24_probe()
710 		return PTR_ERR(at24->vcc_reg);  in at24_probe()
714 		at24->write_max = min_t(unsigned int,  in at24_probe()
716 		if (!i2c_fn_i2c && at24->write_max > I2C_SMBUS_BLOCK_MAX)  in at24_probe()
717 			at24->write_max = I2C_SMBUS_BLOCK_MAX;  in at24_probe()
720 	/* use dummy devices for multiple-address chips */  in at24_probe()
761 	full_power = acpi_dev_state_d0(&client->dev);  in at24_probe()
763 		err = regulator_enable(at24->vcc_reg);  in at24_probe()
774 	 * Perform a one-byte test read to verify that the chip is functional,  in at24_probe()
783 				regulator_disable(at24->vcc_reg);  in at24_probe()
784 			return -ENODEV;  in at24_probe()
788 	at24->nvmem = devm_nvmem_register(dev, &nvmem_config);  in at24_probe()
789 	if (IS_ERR(at24->nvmem)) {  in at24_probe()
792 			regulator_disable(at24->vcc_reg);  in at24_probe()
793 		return dev_err_probe(dev, PTR_ERR(at24->nvmem),  in at24_probe()
805 			 byte_len, client->name, at24->write_max);  in at24_probe()
807 		dev_info(dev, "%u byte %s EEPROM, read-only\n",  in at24_probe()
808 			 byte_len, client->name);  in at24_probe()
817 	pm_runtime_disable(&client->dev);  in at24_remove()
818 	if (acpi_dev_state_d0(&client->dev)) {  in at24_remove()
819 		if (!pm_runtime_status_suspended(&client->dev))  in at24_remove()
820 			regulator_disable(at24->vcc_reg);  in at24_remove()
821 		pm_runtime_set_suspended(&client->dev);  in at24_remove()
830 	return regulator_disable(at24->vcc_reg);  in at24_suspend()
838 	return regulator_enable(at24->vcc_reg);  in at24_resume()
864 		return -EINVAL;  in at24_init()