1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * at24.c - handle most I2C EEPROMs
4 *
5 * Copyright (C) 2005-2007 David Brownell
6 * Copyright (C) 2008 Wolfram Sang, Pengutronix
7 */
8
9 #include <linux/kernel.h>
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/of_device.h>
13 #include <linux/slab.h>
14 #include <linux/delay.h>
15 #include <linux/mutex.h>
16 #include <linux/mod_devicetable.h>
17 #include <linux/bitops.h>
18 #include <linux/jiffies.h>
19 #include <linux/property.h>
20 #include <linux/acpi.h>
21 #include <linux/i2c.h>
22 #include <linux/nvmem-provider.h>
23 #include <linux/regmap.h>
24 #include <linux/pm_runtime.h>
25 #include <linux/gpio/consumer.h>
26
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)
41
42 /*
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).
48 *
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.
54 *
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.)
58 *
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
62 * a bootloader.
63 *
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.
68 */
69
70 struct at24_client {
71 struct i2c_client *client;
72 struct regmap *regmap;
73 };
74
75 struct at24_data {
76 /*
77 * Lock protects against activities from other Linux tasks,
78 * but not from changes by other I2C masters.
79 */
80 struct mutex lock;
81
82 unsigned int write_max;
83 unsigned int num_addresses;
84 unsigned int offset_adj;
85
86 u32 byte_len;
87 u16 page_size;
88 u8 flags;
89
90 struct nvmem_device *nvmem;
91
92 struct gpio_desc *wp_gpio;
93
94 /*
95 * Some chips tie up multiple I2C addresses; dummy devices reserve
96 * them for us, and we'll use them with SMBus calls.
97 */
98 struct at24_client client[];
99 };
100
101 /*
102 * This parameter is to help this driver avoid blocking other drivers out
103 * of I2C for potentially troublesome amounts of time. With a 100 kHz I2C
104 * clock, one 256 byte read takes about 1/43 second which is excessive;
105 * but the 1/170 second it takes at 400 kHz may be quite reasonable; and
106 * at 1 MHz (Fm+) a 1/430 second delay could easily be invisible.
107 *
108 * This value is forced to be a power of two so that writes align on pages.
109 */
110 static unsigned int at24_io_limit = 128;
111 module_param_named(io_limit, at24_io_limit, uint, 0);
112 MODULE_PARM_DESC(at24_io_limit, "Maximum bytes per I/O (default 128)");
113
114 /*
115 * Specs often allow 5 msec for a page write, sometimes 20 msec;
116 * it's important to recover from write timeouts.
117 */
118 static unsigned int at24_write_timeout = 25;
119 module_param_named(write_timeout, at24_write_timeout, uint, 0);
120 MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)");
121
122 struct at24_chip_data {
123 u32 byte_len;
124 u8 flags;
125 };
126
127 #define AT24_CHIP_DATA(_name, _len, _flags) \
128 static const struct at24_chip_data _name = { \
129 .byte_len = _len, .flags = _flags, \
130 }
131
132 /* needs 8 addresses as A0-A2 are ignored */
133 AT24_CHIP_DATA(at24_data_24c00, 128 / 8, AT24_FLAG_TAKE8ADDR);
134 /* old variants can't be handled with this generic entry! */
135 AT24_CHIP_DATA(at24_data_24c01, 1024 / 8, 0);
136 AT24_CHIP_DATA(at24_data_24cs01, 16,
137 AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
138 AT24_CHIP_DATA(at24_data_24c02, 2048 / 8, 0);
139 AT24_CHIP_DATA(at24_data_24cs02, 16,
140 AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
141 AT24_CHIP_DATA(at24_data_24mac402, 48 / 8,
142 AT24_FLAG_MAC | AT24_FLAG_READONLY);
143 AT24_CHIP_DATA(at24_data_24mac602, 64 / 8,
144 AT24_FLAG_MAC | AT24_FLAG_READONLY);
145 /* spd is a 24c02 in memory DIMMs */
146 AT24_CHIP_DATA(at24_data_spd, 2048 / 8,
147 AT24_FLAG_READONLY | AT24_FLAG_IRUGO);
148 AT24_CHIP_DATA(at24_data_24c04, 4096 / 8, 0);
149 AT24_CHIP_DATA(at24_data_24cs04, 16,
150 AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
151 /* 24rf08 quirk is handled at i2c-core */
152 AT24_CHIP_DATA(at24_data_24c08, 8192 / 8, 0);
153 AT24_CHIP_DATA(at24_data_24cs08, 16,
154 AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
155 AT24_CHIP_DATA(at24_data_24c16, 16384 / 8, 0);
156 AT24_CHIP_DATA(at24_data_24cs16, 16,
157 AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
158 AT24_CHIP_DATA(at24_data_24c32, 32768 / 8, AT24_FLAG_ADDR16);
159 AT24_CHIP_DATA(at24_data_24cs32, 16,
160 AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
161 AT24_CHIP_DATA(at24_data_24c64, 65536 / 8, AT24_FLAG_ADDR16);
162 AT24_CHIP_DATA(at24_data_24cs64, 16,
163 AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
164 AT24_CHIP_DATA(at24_data_24c128, 131072 / 8, AT24_FLAG_ADDR16);
165 AT24_CHIP_DATA(at24_data_24c256, 262144 / 8, AT24_FLAG_ADDR16);
166 AT24_CHIP_DATA(at24_data_24c512, 524288 / 8, AT24_FLAG_ADDR16);
167 AT24_CHIP_DATA(at24_data_24c1024, 1048576 / 8, AT24_FLAG_ADDR16);
168 AT24_CHIP_DATA(at24_data_24c2048, 2097152 / 8, AT24_FLAG_ADDR16);
169 /* identical to 24c08 ? */
170 AT24_CHIP_DATA(at24_data_INT3499, 8192 / 8, 0);
171
172 static const struct i2c_device_id at24_ids[] = {
173 { "24c00", (kernel_ulong_t)&at24_data_24c00 },
174 { "24c01", (kernel_ulong_t)&at24_data_24c01 },
175 { "24cs01", (kernel_ulong_t)&at24_data_24cs01 },
176 { "24c02", (kernel_ulong_t)&at24_data_24c02 },
177 { "24cs02", (kernel_ulong_t)&at24_data_24cs02 },
178 { "24mac402", (kernel_ulong_t)&at24_data_24mac402 },
179 { "24mac602", (kernel_ulong_t)&at24_data_24mac602 },
180 { "spd", (kernel_ulong_t)&at24_data_spd },
181 { "24c04", (kernel_ulong_t)&at24_data_24c04 },
182 { "24cs04", (kernel_ulong_t)&at24_data_24cs04 },
183 { "24c08", (kernel_ulong_t)&at24_data_24c08 },
184 { "24cs08", (kernel_ulong_t)&at24_data_24cs08 },
185 { "24c16", (kernel_ulong_t)&at24_data_24c16 },
186 { "24cs16", (kernel_ulong_t)&at24_data_24cs16 },
187 { "24c32", (kernel_ulong_t)&at24_data_24c32 },
188 { "24cs32", (kernel_ulong_t)&at24_data_24cs32 },
189 { "24c64", (kernel_ulong_t)&at24_data_24c64 },
190 { "24cs64", (kernel_ulong_t)&at24_data_24cs64 },
191 { "24c128", (kernel_ulong_t)&at24_data_24c128 },
192 { "24c256", (kernel_ulong_t)&at24_data_24c256 },
193 { "24c512", (kernel_ulong_t)&at24_data_24c512 },
194 { "24c1024", (kernel_ulong_t)&at24_data_24c1024 },
195 { "24c2048", (kernel_ulong_t)&at24_data_24c2048 },
196 { "at24", 0 },
197 { /* END OF LIST */ }
198 };
199 MODULE_DEVICE_TABLE(i2c, at24_ids);
200
201 static const struct of_device_id at24_of_match[] = {
202 { .compatible = "atmel,24c00", .data = &at24_data_24c00 },
203 { .compatible = "atmel,24c01", .data = &at24_data_24c01 },
204 { .compatible = "atmel,24cs01", .data = &at24_data_24cs01 },
205 { .compatible = "atmel,24c02", .data = &at24_data_24c02 },
206 { .compatible = "atmel,24cs02", .data = &at24_data_24cs02 },
207 { .compatible = "atmel,24mac402", .data = &at24_data_24mac402 },
208 { .compatible = "atmel,24mac602", .data = &at24_data_24mac602 },
209 { .compatible = "atmel,spd", .data = &at24_data_spd },
210 { .compatible = "atmel,24c04", .data = &at24_data_24c04 },
211 { .compatible = "atmel,24cs04", .data = &at24_data_24cs04 },
212 { .compatible = "atmel,24c08", .data = &at24_data_24c08 },
213 { .compatible = "atmel,24cs08", .data = &at24_data_24cs08 },
214 { .compatible = "atmel,24c16", .data = &at24_data_24c16 },
215 { .compatible = "atmel,24cs16", .data = &at24_data_24cs16 },
216 { .compatible = "atmel,24c32", .data = &at24_data_24c32 },
217 { .compatible = "atmel,24cs32", .data = &at24_data_24cs32 },
218 { .compatible = "atmel,24c64", .data = &at24_data_24c64 },
219 { .compatible = "atmel,24cs64", .data = &at24_data_24cs64 },
220 { .compatible = "atmel,24c128", .data = &at24_data_24c128 },
221 { .compatible = "atmel,24c256", .data = &at24_data_24c256 },
222 { .compatible = "atmel,24c512", .data = &at24_data_24c512 },
223 { .compatible = "atmel,24c1024", .data = &at24_data_24c1024 },
224 { .compatible = "atmel,24c2048", .data = &at24_data_24c2048 },
225 { /* END OF LIST */ },
226 };
227 MODULE_DEVICE_TABLE(of, at24_of_match);
228
229 static const struct acpi_device_id at24_acpi_ids[] = {
230 { "INT3499", (kernel_ulong_t)&at24_data_INT3499 },
231 { /* END OF LIST */ }
232 };
233 MODULE_DEVICE_TABLE(acpi, at24_acpi_ids);
234
235 /*
236 * This routine supports chips which consume multiple I2C addresses. It
237 * computes the addressing information to be used for a given r/w request.
238 * Assumes that sanity checks for offset happened at sysfs-layer.
239 *
240 * Slave address and byte offset derive from the offset. Always
241 * set the byte address; on a multi-master board, another master
242 * may have changed the chip's "current" address pointer.
243 */
at24_translate_offset(struct at24_data * at24,unsigned int * offset)244 static struct at24_client *at24_translate_offset(struct at24_data *at24,
245 unsigned int *offset)
246 {
247 unsigned int i;
248
249 if (at24->flags & AT24_FLAG_ADDR16) {
250 i = *offset >> 16;
251 *offset &= 0xffff;
252 } else {
253 i = *offset >> 8;
254 *offset &= 0xff;
255 }
256
257 return &at24->client[i];
258 }
259
at24_base_client_dev(struct at24_data * at24)260 static struct device *at24_base_client_dev(struct at24_data *at24)
261 {
262 return &at24->client[0].client->dev;
263 }
264
at24_adjust_read_count(struct at24_data * at24,unsigned int offset,size_t count)265 static size_t at24_adjust_read_count(struct at24_data *at24,
266 unsigned int offset, size_t count)
267 {
268 unsigned int bits;
269 size_t remainder;
270
271 /*
272 * In case of multi-address chips that don't rollover reads to
273 * the next slave address: truncate the count to the slave boundary,
274 * so that the read never straddles slaves.
275 */
276 if (at24->flags & AT24_FLAG_NO_RDROL) {
277 bits = (at24->flags & AT24_FLAG_ADDR16) ? 16 : 8;
278 remainder = BIT(bits) - offset;
279 if (count > remainder)
280 count = remainder;
281 }
282
283 if (count > at24_io_limit)
284 count = at24_io_limit;
285
286 return count;
287 }
288
at24_regmap_read(struct at24_data * at24,char * buf,unsigned int offset,size_t count)289 static ssize_t at24_regmap_read(struct at24_data *at24, char *buf,
290 unsigned int offset, size_t count)
291 {
292 unsigned long timeout, read_time;
293 struct at24_client *at24_client;
294 struct i2c_client *client;
295 struct regmap *regmap;
296 int ret;
297
298 at24_client = at24_translate_offset(at24, &offset);
299 regmap = at24_client->regmap;
300 client = at24_client->client;
301 count = at24_adjust_read_count(at24, offset, count);
302
303 /* adjust offset for mac and serial read ops */
304 offset += at24->offset_adj;
305
306 timeout = jiffies + msecs_to_jiffies(at24_write_timeout);
307 do {
308 /*
309 * The timestamp shall be taken before the actual operation
310 * to avoid a premature timeout in case of high CPU load.
311 */
312 read_time = jiffies;
313
314 ret = regmap_bulk_read(regmap, offset, buf, count);
315 dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n",
316 count, offset, ret, jiffies);
317 if (!ret)
318 return count;
319
320 usleep_range(1000, 1500);
321 } while (time_before(read_time, timeout));
322
323 return -ETIMEDOUT;
324 }
325
326 /*
327 * Note that if the hardware write-protect pin is pulled high, the whole
328 * chip is normally write protected. But there are plenty of product
329 * variants here, including OTP fuses and partial chip protect.
330 *
331 * We only use page mode writes; the alternative is sloooow. These routines
332 * write at most one page.
333 */
334
at24_adjust_write_count(struct at24_data * at24,unsigned int offset,size_t count)335 static size_t at24_adjust_write_count(struct at24_data *at24,
336 unsigned int offset, size_t count)
337 {
338 unsigned int next_page;
339
340 /* write_max is at most a page */
341 if (count > at24->write_max)
342 count = at24->write_max;
343
344 /* Never roll over backwards, to the start of this page */
345 next_page = roundup(offset + 1, at24->page_size);
346 if (offset + count > next_page)
347 count = next_page - offset;
348
349 return count;
350 }
351
at24_regmap_write(struct at24_data * at24,const char * buf,unsigned int offset,size_t count)352 static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf,
353 unsigned int offset, size_t count)
354 {
355 unsigned long timeout, write_time;
356 struct at24_client *at24_client;
357 struct i2c_client *client;
358 struct regmap *regmap;
359 int ret;
360
361 at24_client = at24_translate_offset(at24, &offset);
362 regmap = at24_client->regmap;
363 client = at24_client->client;
364 count = at24_adjust_write_count(at24, offset, count);
365 timeout = jiffies + msecs_to_jiffies(at24_write_timeout);
366
367 do {
368 /*
369 * The timestamp shall be taken before the actual operation
370 * to avoid a premature timeout in case of high CPU load.
371 */
372 write_time = jiffies;
373
374 ret = regmap_bulk_write(regmap, offset, buf, count);
375 dev_dbg(&client->dev, "write %zu@%d --> %d (%ld)\n",
376 count, offset, ret, jiffies);
377 if (!ret)
378 return count;
379
380 usleep_range(1000, 1500);
381 } while (time_before(write_time, timeout));
382
383 return -ETIMEDOUT;
384 }
385
at24_read(void * priv,unsigned int off,void * val,size_t count)386 static int at24_read(void *priv, unsigned int off, void *val, size_t count)
387 {
388 struct at24_data *at24;
389 struct device *dev;
390 char *buf = val;
391 int ret;
392
393 at24 = priv;
394 dev = at24_base_client_dev(at24);
395
396 if (unlikely(!count))
397 return count;
398
399 if (off + count > at24->byte_len)
400 return -EINVAL;
401
402 ret = pm_runtime_get_sync(dev);
403 if (ret < 0) {
404 pm_runtime_put_noidle(dev);
405 return ret;
406 }
407
408 /*
409 * Read data from chip, protecting against concurrent updates
410 * from this host, but not from other I2C masters.
411 */
412 mutex_lock(&at24->lock);
413
414 while (count) {
415 ret = at24_regmap_read(at24, buf, off, count);
416 if (ret < 0) {
417 mutex_unlock(&at24->lock);
418 pm_runtime_put(dev);
419 return ret;
420 }
421 buf += ret;
422 off += ret;
423 count -= ret;
424 }
425
426 mutex_unlock(&at24->lock);
427
428 pm_runtime_put(dev);
429
430 return 0;
431 }
432
at24_write(void * priv,unsigned int off,void * val,size_t count)433 static int at24_write(void *priv, unsigned int off, void *val, size_t count)
434 {
435 struct at24_data *at24;
436 struct device *dev;
437 char *buf = val;
438 int ret;
439
440 at24 = priv;
441 dev = at24_base_client_dev(at24);
442
443 if (unlikely(!count))
444 return -EINVAL;
445
446 if (off + count > at24->byte_len)
447 return -EINVAL;
448
449 ret = pm_runtime_get_sync(dev);
450 if (ret < 0) {
451 pm_runtime_put_noidle(dev);
452 return ret;
453 }
454
455 /*
456 * Write data to chip, protecting against concurrent updates
457 * from this host, but not from other I2C masters.
458 */
459 mutex_lock(&at24->lock);
460 gpiod_set_value_cansleep(at24->wp_gpio, 0);
461
462 while (count) {
463 ret = at24_regmap_write(at24, buf, off, count);
464 if (ret < 0) {
465 gpiod_set_value_cansleep(at24->wp_gpio, 1);
466 mutex_unlock(&at24->lock);
467 pm_runtime_put(dev);
468 return ret;
469 }
470 buf += ret;
471 off += ret;
472 count -= ret;
473 }
474
475 gpiod_set_value_cansleep(at24->wp_gpio, 1);
476 mutex_unlock(&at24->lock);
477
478 pm_runtime_put(dev);
479
480 return 0;
481 }
482
at24_get_chip_data(struct device * dev)483 static const struct at24_chip_data *at24_get_chip_data(struct device *dev)
484 {
485 struct device_node *of_node = dev->of_node;
486 const struct at24_chip_data *cdata;
487 const struct i2c_device_id *id;
488
489 id = i2c_match_id(at24_ids, to_i2c_client(dev));
490
491 /*
492 * The I2C core allows OF nodes compatibles to match against the
493 * I2C device ID table as a fallback, so check not only if an OF
494 * node is present but also if it matches an OF device ID entry.
495 */
496 if (of_node && of_match_device(at24_of_match, dev))
497 cdata = of_device_get_match_data(dev);
498 else if (id)
499 cdata = (void *)id->driver_data;
500 else
501 cdata = acpi_device_get_match_data(dev);
502
503 if (!cdata)
504 return ERR_PTR(-ENODEV);
505
506 return cdata;
507 }
508
at24_make_dummy_client(struct at24_data * at24,unsigned int index,struct regmap_config * regmap_config)509 static int at24_make_dummy_client(struct at24_data *at24, unsigned int index,
510 struct regmap_config *regmap_config)
511 {
512 struct i2c_client *base_client, *dummy_client;
513 struct regmap *regmap;
514 struct device *dev;
515
516 base_client = at24->client[0].client;
517 dev = &base_client->dev;
518
519 dummy_client = devm_i2c_new_dummy_device(dev, base_client->adapter,
520 base_client->addr + index);
521 if (IS_ERR(dummy_client))
522 return PTR_ERR(dummy_client);
523
524 regmap = devm_regmap_init_i2c(dummy_client, regmap_config);
525 if (IS_ERR(regmap))
526 return PTR_ERR(regmap);
527
528 at24->client[index].client = dummy_client;
529 at24->client[index].regmap = regmap;
530
531 return 0;
532 }
533
at24_get_offset_adj(u8 flags,unsigned int byte_len)534 static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len)
535 {
536 if (flags & AT24_FLAG_MAC) {
537 /* EUI-48 starts from 0x9a, EUI-64 from 0x98 */
538 return 0xa0 - byte_len;
539 } else if (flags & AT24_FLAG_SERIAL && flags & AT24_FLAG_ADDR16) {
540 /*
541 * For 16 bit address pointers, the word address must contain
542 * a '10' sequence in bits 11 and 10 regardless of the
543 * intended position of the address pointer.
544 */
545 return 0x0800;
546 } else if (flags & AT24_FLAG_SERIAL) {
547 /*
548 * Otherwise the word address must begin with a '10' sequence,
549 * regardless of the intended address.
550 */
551 return 0x0080;
552 } else {
553 return 0;
554 }
555 }
556
at24_probe(struct i2c_client * client)557 static int at24_probe(struct i2c_client *client)
558 {
559 struct regmap_config regmap_config = { };
560 struct nvmem_config nvmem_config = { };
561 u32 byte_len, page_size, flags, addrw;
562 const struct at24_chip_data *cdata;
563 struct device *dev = &client->dev;
564 bool i2c_fn_i2c, i2c_fn_block;
565 unsigned int i, num_addresses;
566 struct at24_data *at24;
567 struct regmap *regmap;
568 bool writable;
569 u8 test_byte;
570 int err;
571
572 i2c_fn_i2c = i2c_check_functionality(client->adapter, I2C_FUNC_I2C);
573 i2c_fn_block = i2c_check_functionality(client->adapter,
574 I2C_FUNC_SMBUS_WRITE_I2C_BLOCK);
575
576 cdata = at24_get_chip_data(dev);
577 if (IS_ERR(cdata))
578 return PTR_ERR(cdata);
579
580 err = device_property_read_u32(dev, "pagesize", &page_size);
581 if (err)
582 /*
583 * This is slow, but we can't know all eeproms, so we better
584 * play safe. Specifying custom eeprom-types via device tree
585 * or properties is recommended anyhow.
586 */
587 page_size = 1;
588
589 flags = cdata->flags;
590 if (device_property_present(dev, "read-only"))
591 flags |= AT24_FLAG_READONLY;
592 if (device_property_present(dev, "no-read-rollover"))
593 flags |= AT24_FLAG_NO_RDROL;
594
595 err = device_property_read_u32(dev, "address-width", &addrw);
596 if (!err) {
597 switch (addrw) {
598 case 8:
599 if (flags & AT24_FLAG_ADDR16)
600 dev_warn(dev,
601 "Override address width to be 8, while default is 16\n");
602 flags &= ~AT24_FLAG_ADDR16;
603 break;
604 case 16:
605 flags |= AT24_FLAG_ADDR16;
606 break;
607 default:
608 dev_warn(dev, "Bad \"address-width\" property: %u\n",
609 addrw);
610 }
611 }
612
613 err = device_property_read_u32(dev, "size", &byte_len);
614 if (err)
615 byte_len = cdata->byte_len;
616
617 if (!i2c_fn_i2c && !i2c_fn_block)
618 page_size = 1;
619
620 if (!page_size) {
621 dev_err(dev, "page_size must not be 0!\n");
622 return -EINVAL;
623 }
624
625 if (!is_power_of_2(page_size))
626 dev_warn(dev, "page_size looks suspicious (no power of 2)!\n");
627
628 err = device_property_read_u32(dev, "num-addresses", &num_addresses);
629 if (err) {
630 if (flags & AT24_FLAG_TAKE8ADDR)
631 num_addresses = 8;
632 else
633 num_addresses = DIV_ROUND_UP(byte_len,
634 (flags & AT24_FLAG_ADDR16) ? 65536 : 256);
635 }
636
637 if ((flags & AT24_FLAG_SERIAL) && (flags & AT24_FLAG_MAC)) {
638 dev_err(dev,
639 "invalid device data - cannot have both AT24_FLAG_SERIAL & AT24_FLAG_MAC.");
640 return -EINVAL;
641 }
642
643 regmap_config.val_bits = 8;
644 regmap_config.reg_bits = (flags & AT24_FLAG_ADDR16) ? 16 : 8;
645 regmap_config.disable_locking = true;
646
647 regmap = devm_regmap_init_i2c(client, ®map_config);
648 if (IS_ERR(regmap))
649 return PTR_ERR(regmap);
650
651 at24 = devm_kzalloc(dev, struct_size(at24, client, num_addresses),
652 GFP_KERNEL);
653 if (!at24)
654 return -ENOMEM;
655
656 mutex_init(&at24->lock);
657 at24->byte_len = byte_len;
658 at24->page_size = page_size;
659 at24->flags = flags;
660 at24->num_addresses = num_addresses;
661 at24->offset_adj = at24_get_offset_adj(flags, byte_len);
662 at24->client[0].client = client;
663 at24->client[0].regmap = regmap;
664
665 at24->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_HIGH);
666 if (IS_ERR(at24->wp_gpio))
667 return PTR_ERR(at24->wp_gpio);
668
669 writable = !(flags & AT24_FLAG_READONLY);
670 if (writable) {
671 at24->write_max = min_t(unsigned int,
672 page_size, at24_io_limit);
673 if (!i2c_fn_i2c && at24->write_max > I2C_SMBUS_BLOCK_MAX)
674 at24->write_max = I2C_SMBUS_BLOCK_MAX;
675 }
676
677 /* use dummy devices for multiple-address chips */
678 for (i = 1; i < num_addresses; i++) {
679 err = at24_make_dummy_client(at24, i, ®map_config);
680 if (err)
681 return err;
682 }
683
684 nvmem_config.name = dev_name(dev);
685 nvmem_config.dev = dev;
686 nvmem_config.read_only = !writable;
687 nvmem_config.root_only = !(flags & AT24_FLAG_IRUGO);
688 nvmem_config.owner = THIS_MODULE;
689 nvmem_config.compat = true;
690 nvmem_config.base_dev = dev;
691 nvmem_config.reg_read = at24_read;
692 nvmem_config.reg_write = at24_write;
693 nvmem_config.priv = at24;
694 nvmem_config.stride = 1;
695 nvmem_config.word_size = 1;
696 nvmem_config.size = byte_len;
697
698 at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
699 if (IS_ERR(at24->nvmem))
700 return PTR_ERR(at24->nvmem);
701
702 i2c_set_clientdata(client, at24);
703
704 /* enable runtime pm */
705 pm_runtime_set_active(dev);
706 pm_runtime_enable(dev);
707
708 /*
709 * Perform a one-byte test read to verify that the
710 * chip is functional.
711 */
712 err = at24_read(at24, 0, &test_byte, 1);
713 pm_runtime_idle(dev);
714 if (err) {
715 pm_runtime_disable(dev);
716 return -ENODEV;
717 }
718
719 dev_info(dev, "%u byte %s EEPROM, %s, %u bytes/write\n",
720 byte_len, client->name,
721 writable ? "writable" : "read-only", at24->write_max);
722
723 return 0;
724 }
725
at24_remove(struct i2c_client * client)726 static int at24_remove(struct i2c_client *client)
727 {
728 pm_runtime_disable(&client->dev);
729 pm_runtime_set_suspended(&client->dev);
730
731 return 0;
732 }
733
734 static struct i2c_driver at24_driver = {
735 .driver = {
736 .name = "at24",
737 .of_match_table = at24_of_match,
738 .acpi_match_table = ACPI_PTR(at24_acpi_ids),
739 },
740 .probe_new = at24_probe,
741 .remove = at24_remove,
742 .id_table = at24_ids,
743 };
744
at24_init(void)745 static int __init at24_init(void)
746 {
747 if (!at24_io_limit) {
748 pr_err("at24: at24_io_limit must not be 0!\n");
749 return -EINVAL;
750 }
751
752 at24_io_limit = rounddown_pow_of_two(at24_io_limit);
753 return i2c_add_driver(&at24_driver);
754 }
755 module_init(at24_init);
756
at24_exit(void)757 static void __exit at24_exit(void)
758 {
759 i2c_del_driver(&at24_driver);
760 }
761 module_exit(at24_exit);
762
763 MODULE_DESCRIPTION("Driver for most I2C EEPROMs");
764 MODULE_AUTHOR("David Brownell and Wolfram Sang");
765 MODULE_LICENSE("GPL");
766
