1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * at24.c - handle most I2C EEPROMs
5 * Copyright (C) 2005-2007 David Brownell
6 * Copyright (C) 2008 Wolfram Sang, Pengutronix
9 #include <linux/acpi.h>
10 #include <linux/bitops.h>
11 #include <linux/delay.h>
12 #include <linux/i2c.h>
13 #include <linux/init.h>
14 #include <linux/jiffies.h>
15 #include <linux/kernel.h>
16 #include <linux/mod_devicetable.h>
17 #include <linux/module.h>
18 #include <linux/mutex.h>
19 #include <linux/nvmem-provider.h>
20 #include <linux/of_device.h>
21 #include <linux/pm_runtime.h>
22 #include <linux/property.h>
23 #include <linux/regmap.h>
24 #include <linux/regulator/consumer.h>
25 #include <linux/slab.h>
27 /* Address pointer is 16 bit. */
28 #define AT24_FLAG_ADDR16 BIT(7)
29 /* sysfs-entry will be read-only. */
30 #define AT24_FLAG_READONLY BIT(6)
31 /* sysfs-entry will be world-readable. */
32 #define AT24_FLAG_IRUGO BIT(5)
33 /* Take always 8 addresses (24c00). */
34 #define AT24_FLAG_TAKE8ADDR BIT(4)
35 /* Factory-programmed serial number. */
36 #define AT24_FLAG_SERIAL BIT(3)
37 /* Factory-programmed mac address. */
38 #define AT24_FLAG_MAC BIT(2)
39 /* Does not auto-rollover reads to the next slave address. */
40 #define AT24_FLAG_NO_RDROL BIT(1)
43 * I2C EEPROMs from most vendors are inexpensive and mostly interchangeable.
44 * Differences between different vendor product lines (like Atmel AT24C or
45 * MicroChip 24LC, etc) won't much matter for typical read/write access.
46 * There are also I2C RAM chips, likewise interchangeable. One example
47 * would be the PCF8570, which acts like a 24c02 EEPROM (256 bytes).
49 * However, misconfiguration can lose data. "Set 16-bit memory address"
50 * to a part with 8-bit addressing will overwrite data. Writing with too
51 * big a page size also loses data. And it's not safe to assume that the
52 * conventional addresses 0x50..0x57 only hold eeproms; a PCF8563 RTC
53 * uses 0x51, for just one example.
55 * Accordingly, explicit board-specific configuration data should be used
56 * in almost all cases. (One partial exception is an SMBus used to access
57 * "SPD" data for DRAM sticks. Those only use 24c02 EEPROMs.)
59 * So this driver uses "new style" I2C driver binding, expecting to be
60 * told what devices exist. That may be in arch/X/mach-Y/board-Z.c or
61 * similar kernel-resident tables; or, configuration data coming from
64 * Other than binding model, current differences from "eeprom" driver are
65 * that this one handles write access and isn't restricted to 24c02 devices.
66 * It also handles larger devices (32 kbit and up) with two-byte addresses,
67 * which won't work on pure SMBus systems.
71 struct i2c_client *client;
72 struct regmap *regmap;
77 * Lock protects against activities from other Linux tasks,
78 * but not from changes by other I2C masters.
82 unsigned int write_max;
83 unsigned int num_addresses;
84 unsigned int offset_adj;
90 struct nvmem_device *nvmem;
91 struct regulator *vcc_reg;
94 * Some chips tie up multiple I2C addresses; dummy devices reserve
95 * them for us, and we'll use them with SMBus calls.
97 struct at24_client client[];
101 * This parameter is to help this driver avoid blocking other drivers out
102 * of I2C for potentially troublesome amounts of time. With a 100 kHz I2C
103 * clock, one 256 byte read takes about 1/43 second which is excessive;
104 * but the 1/170 second it takes at 400 kHz may be quite reasonable; and
105 * at 1 MHz (Fm+) a 1/430 second delay could easily be invisible.
107 * This value is forced to be a power of two so that writes align on pages.
109 static unsigned int at24_io_limit = 128;
110 module_param_named(io_limit, at24_io_limit, uint, 0);
111 MODULE_PARM_DESC(at24_io_limit, "Maximum bytes per I/O (default 128)");
114 * Specs often allow 5 msec for a page write, sometimes 20 msec;
115 * it's important to recover from write timeouts.
117 static unsigned int at24_write_timeout = 25;
118 module_param_named(write_timeout, at24_write_timeout, uint, 0);
119 MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)");
121 struct at24_chip_data {
126 #define AT24_CHIP_DATA(_name, _len, _flags) \
127 static const struct at24_chip_data _name = { \
128 .byte_len = _len, .flags = _flags, \
131 /* needs 8 addresses as A0-A2 are ignored */
132 AT24_CHIP_DATA(at24_data_24c00, 128 / 8, AT24_FLAG_TAKE8ADDR);
133 /* old variants can't be handled with this generic entry! */
134 AT24_CHIP_DATA(at24_data_24c01, 1024 / 8, 0);
135 AT24_CHIP_DATA(at24_data_24cs01, 16,
136 AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
137 AT24_CHIP_DATA(at24_data_24c02, 2048 / 8, 0);
138 AT24_CHIP_DATA(at24_data_24cs02, 16,
139 AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
140 AT24_CHIP_DATA(at24_data_24mac402, 48 / 8,
141 AT24_FLAG_MAC | AT24_FLAG_READONLY);
142 AT24_CHIP_DATA(at24_data_24mac602, 64 / 8,
143 AT24_FLAG_MAC | AT24_FLAG_READONLY);
144 /* spd is a 24c02 in memory DIMMs */
145 AT24_CHIP_DATA(at24_data_spd, 2048 / 8,
146 AT24_FLAG_READONLY | AT24_FLAG_IRUGO);
147 AT24_CHIP_DATA(at24_data_24c04, 4096 / 8, 0);
148 AT24_CHIP_DATA(at24_data_24cs04, 16,
149 AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
150 /* 24rf08 quirk is handled at i2c-core */
151 AT24_CHIP_DATA(at24_data_24c08, 8192 / 8, 0);
152 AT24_CHIP_DATA(at24_data_24cs08, 16,
153 AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
154 AT24_CHIP_DATA(at24_data_24c16, 16384 / 8, 0);
155 AT24_CHIP_DATA(at24_data_24cs16, 16,
156 AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
157 AT24_CHIP_DATA(at24_data_24c32, 32768 / 8, AT24_FLAG_ADDR16);
158 AT24_CHIP_DATA(at24_data_24cs32, 16,
159 AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
160 AT24_CHIP_DATA(at24_data_24c64, 65536 / 8, AT24_FLAG_ADDR16);
161 AT24_CHIP_DATA(at24_data_24cs64, 16,
162 AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
163 AT24_CHIP_DATA(at24_data_24c128, 131072 / 8, AT24_FLAG_ADDR16);
164 AT24_CHIP_DATA(at24_data_24c256, 262144 / 8, AT24_FLAG_ADDR16);
165 AT24_CHIP_DATA(at24_data_24c512, 524288 / 8, AT24_FLAG_ADDR16);
166 AT24_CHIP_DATA(at24_data_24c1024, 1048576 / 8, AT24_FLAG_ADDR16);
167 AT24_CHIP_DATA(at24_data_24c2048, 2097152 / 8, AT24_FLAG_ADDR16);
168 /* identical to 24c08 ? */
169 AT24_CHIP_DATA(at24_data_INT3499, 8192 / 8, 0);
171 static const struct i2c_device_id at24_ids[] = {
172 { "24c00", (kernel_ulong_t)&at24_data_24c00 },
173 { "24c01", (kernel_ulong_t)&at24_data_24c01 },
174 { "24cs01", (kernel_ulong_t)&at24_data_24cs01 },
175 { "24c02", (kernel_ulong_t)&at24_data_24c02 },
176 { "24cs02", (kernel_ulong_t)&at24_data_24cs02 },
177 { "24mac402", (kernel_ulong_t)&at24_data_24mac402 },
178 { "24mac602", (kernel_ulong_t)&at24_data_24mac602 },
179 { "spd", (kernel_ulong_t)&at24_data_spd },
180 { "24c04", (kernel_ulong_t)&at24_data_24c04 },
181 { "24cs04", (kernel_ulong_t)&at24_data_24cs04 },
182 { "24c08", (kernel_ulong_t)&at24_data_24c08 },
183 { "24cs08", (kernel_ulong_t)&at24_data_24cs08 },
184 { "24c16", (kernel_ulong_t)&at24_data_24c16 },
185 { "24cs16", (kernel_ulong_t)&at24_data_24cs16 },
186 { "24c32", (kernel_ulong_t)&at24_data_24c32 },
187 { "24cs32", (kernel_ulong_t)&at24_data_24cs32 },
188 { "24c64", (kernel_ulong_t)&at24_data_24c64 },
189 { "24cs64", (kernel_ulong_t)&at24_data_24cs64 },
190 { "24c128", (kernel_ulong_t)&at24_data_24c128 },
191 { "24c256", (kernel_ulong_t)&at24_data_24c256 },
192 { "24c512", (kernel_ulong_t)&at24_data_24c512 },
193 { "24c1024", (kernel_ulong_t)&at24_data_24c1024 },
194 { "24c2048", (kernel_ulong_t)&at24_data_24c2048 },
196 { /* END OF LIST */ }
198 MODULE_DEVICE_TABLE(i2c, at24_ids);
200 static const struct of_device_id at24_of_match[] = {
201 { .compatible = "atmel,24c00", .data = &at24_data_24c00 },
202 { .compatible = "atmel,24c01", .data = &at24_data_24c01 },
203 { .compatible = "atmel,24cs01", .data = &at24_data_24cs01 },
204 { .compatible = "atmel,24c02", .data = &at24_data_24c02 },
205 { .compatible = "atmel,24cs02", .data = &at24_data_24cs02 },
206 { .compatible = "atmel,24mac402", .data = &at24_data_24mac402 },
207 { .compatible = "atmel,24mac602", .data = &at24_data_24mac602 },
208 { .compatible = "atmel,spd", .data = &at24_data_spd },
209 { .compatible = "atmel,24c04", .data = &at24_data_24c04 },
210 { .compatible = "atmel,24cs04", .data = &at24_data_24cs04 },
211 { .compatible = "atmel,24c08", .data = &at24_data_24c08 },
212 { .compatible = "atmel,24cs08", .data = &at24_data_24cs08 },
213 { .compatible = "atmel,24c16", .data = &at24_data_24c16 },
214 { .compatible = "atmel,24cs16", .data = &at24_data_24cs16 },
215 { .compatible = "atmel,24c32", .data = &at24_data_24c32 },
216 { .compatible = "atmel,24cs32", .data = &at24_data_24cs32 },
217 { .compatible = "atmel,24c64", .data = &at24_data_24c64 },
218 { .compatible = "atmel,24cs64", .data = &at24_data_24cs64 },
219 { .compatible = "atmel,24c128", .data = &at24_data_24c128 },
220 { .compatible = "atmel,24c256", .data = &at24_data_24c256 },
221 { .compatible = "atmel,24c512", .data = &at24_data_24c512 },
222 { .compatible = "atmel,24c1024", .data = &at24_data_24c1024 },
223 { .compatible = "atmel,24c2048", .data = &at24_data_24c2048 },
224 { /* END OF LIST */ },
226 MODULE_DEVICE_TABLE(of, at24_of_match);
228 static const struct acpi_device_id at24_acpi_ids[] = {
229 { "INT3499", (kernel_ulong_t)&at24_data_INT3499 },
230 { /* END OF LIST */ }
232 MODULE_DEVICE_TABLE(acpi, at24_acpi_ids);
235 * This routine supports chips which consume multiple I2C addresses. It
236 * computes the addressing information to be used for a given r/w request.
237 * Assumes that sanity checks for offset happened at sysfs-layer.
239 * Slave address and byte offset derive from the offset. Always
240 * set the byte address; on a multi-master board, another master
241 * may have changed the chip's "current" address pointer.
243 static struct at24_client *at24_translate_offset(struct at24_data *at24,
244 unsigned int *offset)
248 if (at24->flags & AT24_FLAG_ADDR16) {
256 return &at24->client[i];
259 static struct device *at24_base_client_dev(struct at24_data *at24)
261 return &at24->client[0].client->dev;
264 static size_t at24_adjust_read_count(struct at24_data *at24,
265 unsigned int offset, size_t count)
271 * In case of multi-address chips that don't rollover reads to
272 * the next slave address: truncate the count to the slave boundary,
273 * so that the read never straddles slaves.
275 if (at24->flags & AT24_FLAG_NO_RDROL) {
276 bits = (at24->flags & AT24_FLAG_ADDR16) ? 16 : 8;
277 remainder = BIT(bits) - offset;
278 if (count > remainder)
282 if (count > at24_io_limit)
283 count = at24_io_limit;
288 static ssize_t at24_regmap_read(struct at24_data *at24, char *buf,
289 unsigned int offset, size_t count)
291 unsigned long timeout, read_time;
292 struct at24_client *at24_client;
293 struct i2c_client *client;
294 struct regmap *regmap;
297 at24_client = at24_translate_offset(at24, &offset);
298 regmap = at24_client->regmap;
299 client = at24_client->client;
300 count = at24_adjust_read_count(at24, offset, count);
302 /* adjust offset for mac and serial read ops */
303 offset += at24->offset_adj;
305 timeout = jiffies + msecs_to_jiffies(at24_write_timeout);
308 * The timestamp shall be taken before the actual operation
309 * to avoid a premature timeout in case of high CPU load.
313 ret = regmap_bulk_read(regmap, offset, buf, count);
314 dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n",
315 count, offset, ret, jiffies);
319 usleep_range(1000, 1500);
320 } while (time_before(read_time, timeout));
326 * Note that if the hardware write-protect pin is pulled high, the whole
327 * chip is normally write protected. But there are plenty of product
328 * variants here, including OTP fuses and partial chip protect.
330 * We only use page mode writes; the alternative is sloooow. These routines
331 * write at most one page.
334 static size_t at24_adjust_write_count(struct at24_data *at24,
335 unsigned int offset, size_t count)
337 unsigned int next_page;
339 /* write_max is at most a page */
340 if (count > at24->write_max)
341 count = at24->write_max;
343 /* Never roll over backwards, to the start of this page */
344 next_page = roundup(offset + 1, at24->page_size);
345 if (offset + count > next_page)
346 count = next_page - offset;
351 static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf,
352 unsigned int offset, size_t count)
354 unsigned long timeout, write_time;
355 struct at24_client *at24_client;
356 struct i2c_client *client;
357 struct regmap *regmap;
360 at24_client = at24_translate_offset(at24, &offset);
361 regmap = at24_client->regmap;
362 client = at24_client->client;
363 count = at24_adjust_write_count(at24, offset, count);
364 timeout = jiffies + msecs_to_jiffies(at24_write_timeout);
368 * The timestamp shall be taken before the actual operation
369 * to avoid a premature timeout in case of high CPU load.
371 write_time = jiffies;
373 ret = regmap_bulk_write(regmap, offset, buf, count);
374 dev_dbg(&client->dev, "write %zu@%d --> %d (%ld)\n",
375 count, offset, ret, jiffies);
379 usleep_range(1000, 1500);
380 } while (time_before(write_time, timeout));
385 static int at24_read(void *priv, unsigned int off, void *val, size_t count)
387 struct at24_data *at24;
393 dev = at24_base_client_dev(at24);
395 if (unlikely(!count))
398 if (off + count > at24->byte_len)
401 ret = pm_runtime_get_sync(dev);
403 pm_runtime_put_noidle(dev);
408 * Read data from chip, protecting against concurrent updates
409 * from this host, but not from other I2C masters.
411 mutex_lock(&at24->lock);
414 ret = at24_regmap_read(at24, buf, off, count);
416 mutex_unlock(&at24->lock);
425 mutex_unlock(&at24->lock);
432 static int at24_write(void *priv, unsigned int off, void *val, size_t count)
434 struct at24_data *at24;
440 dev = at24_base_client_dev(at24);
442 if (unlikely(!count))
445 if (off + count > at24->byte_len)
448 ret = pm_runtime_get_sync(dev);
450 pm_runtime_put_noidle(dev);
455 * Write data to chip, protecting against concurrent updates
456 * from this host, but not from other I2C masters.
458 mutex_lock(&at24->lock);
461 ret = at24_regmap_write(at24, buf, off, count);
463 mutex_unlock(&at24->lock);
472 mutex_unlock(&at24->lock);
479 static const struct at24_chip_data *at24_get_chip_data(struct device *dev)
481 struct device_node *of_node = dev->of_node;
482 const struct at24_chip_data *cdata;
483 const struct i2c_device_id *id;
485 id = i2c_match_id(at24_ids, to_i2c_client(dev));
488 * The I2C core allows OF nodes compatibles to match against the
489 * I2C device ID table as a fallback, so check not only if an OF
490 * node is present but also if it matches an OF device ID entry.
492 if (of_node && of_match_device(at24_of_match, dev))
493 cdata = of_device_get_match_data(dev);
495 cdata = (void *)id->driver_data;
497 cdata = acpi_device_get_match_data(dev);
500 return ERR_PTR(-ENODEV);
505 static int at24_make_dummy_client(struct at24_data *at24, unsigned int index,
506 struct regmap_config *regmap_config)
508 struct i2c_client *base_client, *dummy_client;
509 struct regmap *regmap;
512 base_client = at24->client[0].client;
513 dev = &base_client->dev;
515 dummy_client = devm_i2c_new_dummy_device(dev, base_client->adapter,
516 base_client->addr + index);
517 if (IS_ERR(dummy_client))
518 return PTR_ERR(dummy_client);
520 regmap = devm_regmap_init_i2c(dummy_client, regmap_config);
522 return PTR_ERR(regmap);
524 at24->client[index].client = dummy_client;
525 at24->client[index].regmap = regmap;
530 static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len)
532 if (flags & AT24_FLAG_MAC) {
533 /* EUI-48 starts from 0x9a, EUI-64 from 0x98 */
534 return 0xa0 - byte_len;
535 } else if (flags & AT24_FLAG_SERIAL && flags & AT24_FLAG_ADDR16) {
537 * For 16 bit address pointers, the word address must contain
538 * a '10' sequence in bits 11 and 10 regardless of the
539 * intended position of the address pointer.
542 } else if (flags & AT24_FLAG_SERIAL) {
544 * Otherwise the word address must begin with a '10' sequence,
545 * regardless of the intended address.
553 static int at24_probe(struct i2c_client *client)
555 struct regmap_config regmap_config = { };
556 struct nvmem_config nvmem_config = { };
557 u32 byte_len, page_size, flags, addrw;
558 const struct at24_chip_data *cdata;
559 struct device *dev = &client->dev;
560 bool i2c_fn_i2c, i2c_fn_block;
561 unsigned int i, num_addresses;
562 struct at24_data *at24;
563 struct regmap *regmap;
568 i2c_fn_i2c = i2c_check_functionality(client->adapter, I2C_FUNC_I2C);
569 i2c_fn_block = i2c_check_functionality(client->adapter,
570 I2C_FUNC_SMBUS_WRITE_I2C_BLOCK);
572 cdata = at24_get_chip_data(dev);
574 return PTR_ERR(cdata);
576 err = device_property_read_u32(dev, "pagesize", &page_size);
579 * This is slow, but we can't know all eeproms, so we better
580 * play safe. Specifying custom eeprom-types via device tree
581 * or properties is recommended anyhow.
585 flags = cdata->flags;
586 if (device_property_present(dev, "read-only"))
587 flags |= AT24_FLAG_READONLY;
588 if (device_property_present(dev, "no-read-rollover"))
589 flags |= AT24_FLAG_NO_RDROL;
591 err = device_property_read_u32(dev, "address-width", &addrw);
595 if (flags & AT24_FLAG_ADDR16)
597 "Override address width to be 8, while default is 16\n");
598 flags &= ~AT24_FLAG_ADDR16;
601 flags |= AT24_FLAG_ADDR16;
604 dev_warn(dev, "Bad \"address-width\" property: %u\n",
609 err = device_property_read_u32(dev, "size", &byte_len);
611 byte_len = cdata->byte_len;
613 if (!i2c_fn_i2c && !i2c_fn_block)
617 dev_err(dev, "page_size must not be 0!\n");
621 if (!is_power_of_2(page_size))
622 dev_warn(dev, "page_size looks suspicious (no power of 2)!\n");
624 err = device_property_read_u32(dev, "num-addresses", &num_addresses);
626 if (flags & AT24_FLAG_TAKE8ADDR)
629 num_addresses = DIV_ROUND_UP(byte_len,
630 (flags & AT24_FLAG_ADDR16) ? 65536 : 256);
633 if ((flags & AT24_FLAG_SERIAL) && (flags & AT24_FLAG_MAC)) {
635 "invalid device data - cannot have both AT24_FLAG_SERIAL & AT24_FLAG_MAC.");
639 regmap_config.val_bits = 8;
640 regmap_config.reg_bits = (flags & AT24_FLAG_ADDR16) ? 16 : 8;
641 regmap_config.disable_locking = true;
643 regmap = devm_regmap_init_i2c(client, ®map_config);
645 return PTR_ERR(regmap);
647 at24 = devm_kzalloc(dev, struct_size(at24, client, num_addresses),
652 mutex_init(&at24->lock);
653 at24->byte_len = byte_len;
654 at24->page_size = page_size;
656 at24->num_addresses = num_addresses;
657 at24->offset_adj = at24_get_offset_adj(flags, byte_len);
658 at24->client[0].client = client;
659 at24->client[0].regmap = regmap;
661 at24->vcc_reg = devm_regulator_get(dev, "vcc");
662 if (IS_ERR(at24->vcc_reg))
663 return PTR_ERR(at24->vcc_reg);
665 writable = !(flags & AT24_FLAG_READONLY);
667 at24->write_max = min_t(unsigned int,
668 page_size, at24_io_limit);
669 if (!i2c_fn_i2c && at24->write_max > I2C_SMBUS_BLOCK_MAX)
670 at24->write_max = I2C_SMBUS_BLOCK_MAX;
673 /* use dummy devices for multiple-address chips */
674 for (i = 1; i < num_addresses; i++) {
675 err = at24_make_dummy_client(at24, i, ®map_config);
680 nvmem_config.name = dev_name(dev);
681 nvmem_config.dev = dev;
682 nvmem_config.read_only = !writable;
683 nvmem_config.root_only = !(flags & AT24_FLAG_IRUGO);
684 nvmem_config.owner = THIS_MODULE;
685 nvmem_config.compat = true;
686 nvmem_config.base_dev = dev;
687 nvmem_config.reg_read = at24_read;
688 nvmem_config.reg_write = at24_write;
689 nvmem_config.priv = at24;
690 nvmem_config.stride = 1;
691 nvmem_config.word_size = 1;
692 nvmem_config.size = byte_len;
694 at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
695 if (IS_ERR(at24->nvmem))
696 return PTR_ERR(at24->nvmem);
698 i2c_set_clientdata(client, at24);
700 err = regulator_enable(at24->vcc_reg);
702 dev_err(dev, "Failed to enable vcc regulator\n");
706 /* enable runtime pm */
707 pm_runtime_set_active(dev);
708 pm_runtime_enable(dev);
711 * Perform a one-byte test read to verify that the
712 * chip is functional.
714 err = at24_read(at24, 0, &test_byte, 1);
715 pm_runtime_idle(dev);
717 pm_runtime_disable(dev);
718 regulator_disable(at24->vcc_reg);
723 dev_info(dev, "%u byte %s EEPROM, writable, %u bytes/write\n",
724 byte_len, client->name, at24->write_max);
726 dev_info(dev, "%u byte %s EEPROM, read-only\n",
727 byte_len, client->name);
732 static int at24_remove(struct i2c_client *client)
734 struct at24_data *at24 = i2c_get_clientdata(client);
736 pm_runtime_disable(&client->dev);
737 if (!pm_runtime_status_suspended(&client->dev))
738 regulator_disable(at24->vcc_reg);
739 pm_runtime_set_suspended(&client->dev);
744 static int __maybe_unused at24_suspend(struct device *dev)
746 struct i2c_client *client = to_i2c_client(dev);
747 struct at24_data *at24 = i2c_get_clientdata(client);
749 return regulator_disable(at24->vcc_reg);
752 static int __maybe_unused at24_resume(struct device *dev)
754 struct i2c_client *client = to_i2c_client(dev);
755 struct at24_data *at24 = i2c_get_clientdata(client);
757 return regulator_enable(at24->vcc_reg);
760 static const struct dev_pm_ops at24_pm_ops = {
761 SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
762 pm_runtime_force_resume)
763 SET_RUNTIME_PM_OPS(at24_suspend, at24_resume, NULL)
766 static struct i2c_driver at24_driver = {
770 .of_match_table = at24_of_match,
771 .acpi_match_table = ACPI_PTR(at24_acpi_ids),
773 .probe_new = at24_probe,
774 .remove = at24_remove,
775 .id_table = at24_ids,
778 static int __init at24_init(void)
780 if (!at24_io_limit) {
781 pr_err("at24: at24_io_limit must not be 0!\n");
785 at24_io_limit = rounddown_pow_of_two(at24_io_limit);
786 return i2c_add_driver(&at24_driver);
788 module_init(at24_init);
790 static void __exit at24_exit(void)
792 i2c_del_driver(&at24_driver);
794 module_exit(at24_exit);
796 MODULE_DESCRIPTION("Driver for most I2C EEPROMs");
797 MODULE_AUTHOR("David Brownell and Wolfram Sang");
798 MODULE_LICENSE("GPL");