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/log2.h>
 18#include <linux/bitops.h>
 19#include <linux/jiffies.h>
 20#include <linux/property.h>
 21#include <linux/acpi.h>
 22#include <linux/i2c.h>
 23#include <linux/nvmem-provider.h>
 24#include <linux/regmap.h>
 25#include <linux/platform_data/at24.h>
 26#include <linux/pm_runtime.h>
 27#include <linux/gpio/consumer.h>
 28
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 29/*
 30 * I2C EEPROMs from most vendors are inexpensive and mostly interchangeable.
 31 * Differences between different vendor product lines (like Atmel AT24C or
 32 * MicroChip 24LC, etc) won't much matter for typical read/write access.
 33 * There are also I2C RAM chips, likewise interchangeable. One example
 34 * would be the PCF8570, which acts like a 24c02 EEPROM (256 bytes).
 35 *
 36 * However, misconfiguration can lose data. "Set 16-bit memory address"
 37 * to a part with 8-bit addressing will overwrite data. Writing with too
 38 * big a page size also loses data. And it's not safe to assume that the
 39 * conventional addresses 0x50..0x57 only hold eeproms; a PCF8563 RTC
 40 * uses 0x51, for just one example.
 41 *
 42 * Accordingly, explicit board-specific configuration data should be used
 43 * in almost all cases. (One partial exception is an SMBus used to access
 44 * "SPD" data for DRAM sticks. Those only use 24c02 EEPROMs.)
 45 *
 46 * So this driver uses "new style" I2C driver binding, expecting to be
 47 * told what devices exist. That may be in arch/X/mach-Y/board-Z.c or
 48 * similar kernel-resident tables; or, configuration data coming from
 49 * a bootloader.
 50 *
 51 * Other than binding model, current differences from "eeprom" driver are
 52 * that this one handles write access and isn't restricted to 24c02 devices.
 53 * It also handles larger devices (32 kbit and up) with two-byte addresses,
 54 * which won't work on pure SMBus systems.
 55 */
 56
 57struct at24_client {
 58	struct i2c_client *client;
 59	struct regmap *regmap;
 60};
 61
 62struct at24_data {
 63	/*
 64	 * Lock protects against activities from other Linux tasks,
 65	 * but not from changes by other I2C masters.
 66	 */
 67	struct mutex lock;
 68
 69	unsigned int write_max;
 70	unsigned int num_addresses;
 71	unsigned int offset_adj;
 72
 73	u32 byte_len;
 74	u16 page_size;
 75	u8 flags;
 76
 77	struct nvmem_device *nvmem;
 78
 79	struct gpio_desc *wp_gpio;
 80
 81	/*
 82	 * Some chips tie up multiple I2C addresses; dummy devices reserve
 83	 * them for us, and we'll use them with SMBus calls.
 84	 */
 85	struct at24_client client[];
 86};
 87
 88/*
 89 * This parameter is to help this driver avoid blocking other drivers out
 90 * of I2C for potentially troublesome amounts of time. With a 100 kHz I2C
 91 * clock, one 256 byte read takes about 1/43 second which is excessive;
 92 * but the 1/170 second it takes at 400 kHz may be quite reasonable; and
 93 * at 1 MHz (Fm+) a 1/430 second delay could easily be invisible.
 94 *
 95 * This value is forced to be a power of two so that writes align on pages.
 96 */
 97static unsigned int at24_io_limit = 128;
 98module_param_named(io_limit, at24_io_limit, uint, 0);
 99MODULE_PARM_DESC(at24_io_limit, "Maximum bytes per I/O (default 128)");
100
101/*
102 * Specs often allow 5 msec for a page write, sometimes 20 msec;
103 * it's important to recover from write timeouts.
104 */
105static unsigned int at24_write_timeout = 25;
106module_param_named(write_timeout, at24_write_timeout, uint, 0);
107MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)");
108
109/*
110 * Both reads and writes fail if the previous write didn't complete yet. This
111 * macro loops a few times waiting at least long enough for one entire page
112 * write to work while making sure that at least one iteration is run before
113 * checking the break condition.
114 *
115 * It takes two parameters: a variable in which the future timeout in jiffies
116 * will be stored and a temporary variable holding the time of the last
117 * iteration of processing the request. Both should be unsigned integers
118 * holding at least 32 bits.
119 */
120#define at24_loop_until_timeout(tout, op_time)				\
121	for (tout = jiffies + msecs_to_jiffies(at24_write_timeout),	\
122	     op_time = 0;						\
123	     op_time ? time_before(op_time, tout) : true;		\
124	     usleep_range(1000, 1500), op_time = jiffies)
125
126struct at24_chip_data {
127	/*
128	 * these fields mirror their equivalents in
129	 * struct at24_platform_data
130	 */
131	u32 byte_len;
132	u8 flags;
133};
134
135#define AT24_CHIP_DATA(_name, _len, _flags)				\
136	static const struct at24_chip_data _name = {			\
137		.byte_len = _len, .flags = _flags,			\
138	}
139
140/* needs 8 addresses as A0-A2 are ignored */
141AT24_CHIP_DATA(at24_data_24c00, 128 / 8, AT24_FLAG_TAKE8ADDR);
142/* old variants can't be handled with this generic entry! */
143AT24_CHIP_DATA(at24_data_24c01, 1024 / 8, 0);
144AT24_CHIP_DATA(at24_data_24cs01, 16,
145	AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
146AT24_CHIP_DATA(at24_data_24c02, 2048 / 8, 0);
147AT24_CHIP_DATA(at24_data_24cs02, 16,
148	AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
149AT24_CHIP_DATA(at24_data_24mac402, 48 / 8,
150	AT24_FLAG_MAC | AT24_FLAG_READONLY);
151AT24_CHIP_DATA(at24_data_24mac602, 64 / 8,
152	AT24_FLAG_MAC | AT24_FLAG_READONLY);
153/* spd is a 24c02 in memory DIMMs */
154AT24_CHIP_DATA(at24_data_spd, 2048 / 8,
155	AT24_FLAG_READONLY | AT24_FLAG_IRUGO);
156AT24_CHIP_DATA(at24_data_24c04, 4096 / 8, 0);
157AT24_CHIP_DATA(at24_data_24cs04, 16,
158	AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
159/* 24rf08 quirk is handled at i2c-core */
160AT24_CHIP_DATA(at24_data_24c08, 8192 / 8, 0);
161AT24_CHIP_DATA(at24_data_24cs08, 16,
162	AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
163AT24_CHIP_DATA(at24_data_24c16, 16384 / 8, 0);
164AT24_CHIP_DATA(at24_data_24cs16, 16,
165	AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
166AT24_CHIP_DATA(at24_data_24c32, 32768 / 8, AT24_FLAG_ADDR16);
167AT24_CHIP_DATA(at24_data_24cs32, 16,
168	AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
169AT24_CHIP_DATA(at24_data_24c64, 65536 / 8, AT24_FLAG_ADDR16);
170AT24_CHIP_DATA(at24_data_24cs64, 16,
171	AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
172AT24_CHIP_DATA(at24_data_24c128, 131072 / 8, AT24_FLAG_ADDR16);
173AT24_CHIP_DATA(at24_data_24c256, 262144 / 8, AT24_FLAG_ADDR16);
174AT24_CHIP_DATA(at24_data_24c512, 524288 / 8, AT24_FLAG_ADDR16);
175AT24_CHIP_DATA(at24_data_24c1024, 1048576 / 8, AT24_FLAG_ADDR16);
 
176/* identical to 24c08 ? */
177AT24_CHIP_DATA(at24_data_INT3499, 8192 / 8, 0);
178
179static const struct i2c_device_id at24_ids[] = {
180	{ "24c00",	(kernel_ulong_t)&at24_data_24c00 },
181	{ "24c01",	(kernel_ulong_t)&at24_data_24c01 },
182	{ "24cs01",	(kernel_ulong_t)&at24_data_24cs01 },
183	{ "24c02",	(kernel_ulong_t)&at24_data_24c02 },
184	{ "24cs02",	(kernel_ulong_t)&at24_data_24cs02 },
185	{ "24mac402",	(kernel_ulong_t)&at24_data_24mac402 },
186	{ "24mac602",	(kernel_ulong_t)&at24_data_24mac602 },
187	{ "spd",	(kernel_ulong_t)&at24_data_spd },
188	{ "24c04",	(kernel_ulong_t)&at24_data_24c04 },
189	{ "24cs04",	(kernel_ulong_t)&at24_data_24cs04 },
190	{ "24c08",	(kernel_ulong_t)&at24_data_24c08 },
191	{ "24cs08",	(kernel_ulong_t)&at24_data_24cs08 },
192	{ "24c16",	(kernel_ulong_t)&at24_data_24c16 },
193	{ "24cs16",	(kernel_ulong_t)&at24_data_24cs16 },
194	{ "24c32",	(kernel_ulong_t)&at24_data_24c32 },
195	{ "24cs32",	(kernel_ulong_t)&at24_data_24cs32 },
196	{ "24c64",	(kernel_ulong_t)&at24_data_24c64 },
197	{ "24cs64",	(kernel_ulong_t)&at24_data_24cs64 },
198	{ "24c128",	(kernel_ulong_t)&at24_data_24c128 },
199	{ "24c256",	(kernel_ulong_t)&at24_data_24c256 },
200	{ "24c512",	(kernel_ulong_t)&at24_data_24c512 },
201	{ "24c1024",	(kernel_ulong_t)&at24_data_24c1024 },
 
202	{ "at24",	0 },
203	{ /* END OF LIST */ }
204};
205MODULE_DEVICE_TABLE(i2c, at24_ids);
206
207static const struct of_device_id at24_of_match[] = {
208	{ .compatible = "atmel,24c00",		.data = &at24_data_24c00 },
209	{ .compatible = "atmel,24c01",		.data = &at24_data_24c01 },
210	{ .compatible = "atmel,24cs01",		.data = &at24_data_24cs01 },
211	{ .compatible = "atmel,24c02",		.data = &at24_data_24c02 },
212	{ .compatible = "atmel,24cs02",		.data = &at24_data_24cs02 },
213	{ .compatible = "atmel,24mac402",	.data = &at24_data_24mac402 },
214	{ .compatible = "atmel,24mac602",	.data = &at24_data_24mac602 },
215	{ .compatible = "atmel,spd",		.data = &at24_data_spd },
216	{ .compatible = "atmel,24c04",		.data = &at24_data_24c04 },
217	{ .compatible = "atmel,24cs04",		.data = &at24_data_24cs04 },
218	{ .compatible = "atmel,24c08",		.data = &at24_data_24c08 },
219	{ .compatible = "atmel,24cs08",		.data = &at24_data_24cs08 },
220	{ .compatible = "atmel,24c16",		.data = &at24_data_24c16 },
221	{ .compatible = "atmel,24cs16",		.data = &at24_data_24cs16 },
222	{ .compatible = "atmel,24c32",		.data = &at24_data_24c32 },
223	{ .compatible = "atmel,24cs32",		.data = &at24_data_24cs32 },
224	{ .compatible = "atmel,24c64",		.data = &at24_data_24c64 },
225	{ .compatible = "atmel,24cs64",		.data = &at24_data_24cs64 },
226	{ .compatible = "atmel,24c128",		.data = &at24_data_24c128 },
227	{ .compatible = "atmel,24c256",		.data = &at24_data_24c256 },
228	{ .compatible = "atmel,24c512",		.data = &at24_data_24c512 },
229	{ .compatible = "atmel,24c1024",	.data = &at24_data_24c1024 },
 
230	{ /* END OF LIST */ },
231};
232MODULE_DEVICE_TABLE(of, at24_of_match);
233
234static const struct acpi_device_id at24_acpi_ids[] = {
235	{ "INT3499",	(kernel_ulong_t)&at24_data_INT3499 },
236	{ /* END OF LIST */ }
237};
238MODULE_DEVICE_TABLE(acpi, at24_acpi_ids);
239
240/*
241 * This routine supports chips which consume multiple I2C addresses. It
242 * computes the addressing information to be used for a given r/w request.
243 * Assumes that sanity checks for offset happened at sysfs-layer.
244 *
245 * Slave address and byte offset derive from the offset. Always
246 * set the byte address; on a multi-master board, another master
247 * may have changed the chip's "current" address pointer.
248 */
249static struct at24_client *at24_translate_offset(struct at24_data *at24,
250						 unsigned int *offset)
251{
252	unsigned int i;
253
254	if (at24->flags & AT24_FLAG_ADDR16) {
255		i = *offset >> 16;
256		*offset &= 0xffff;
257	} else {
258		i = *offset >> 8;
259		*offset &= 0xff;
260	}
261
262	return &at24->client[i];
263}
264
265static struct device *at24_base_client_dev(struct at24_data *at24)
266{
267	return &at24->client[0].client->dev;
268}
269
270static size_t at24_adjust_read_count(struct at24_data *at24,
271				      unsigned int offset, size_t count)
272{
273	unsigned int bits;
274	size_t remainder;
275
276	/*
277	 * In case of multi-address chips that don't rollover reads to
278	 * the next slave address: truncate the count to the slave boundary,
279	 * so that the read never straddles slaves.
280	 */
281	if (at24->flags & AT24_FLAG_NO_RDROL) {
282		bits = (at24->flags & AT24_FLAG_ADDR16) ? 16 : 8;
283		remainder = BIT(bits) - offset;
284		if (count > remainder)
285			count = remainder;
286	}
287
288	if (count > at24_io_limit)
289		count = at24_io_limit;
290
291	return count;
292}
293
294static ssize_t at24_regmap_read(struct at24_data *at24, char *buf,
295				unsigned int offset, size_t count)
296{
297	unsigned long timeout, read_time;
298	struct at24_client *at24_client;
299	struct i2c_client *client;
300	struct regmap *regmap;
301	int ret;
302
303	at24_client = at24_translate_offset(at24, &offset);
304	regmap = at24_client->regmap;
305	client = at24_client->client;
306	count = at24_adjust_read_count(at24, offset, count);
307
308	/* adjust offset for mac and serial read ops */
309	offset += at24->offset_adj;
310
311	at24_loop_until_timeout(timeout, read_time) {
 
 
 
 
 
 
 
312		ret = regmap_bulk_read(regmap, offset, buf, count);
313		dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n",
314			count, offset, ret, jiffies);
315		if (!ret)
316			return count;
317	}
 
 
318
319	return -ETIMEDOUT;
320}
321
322/*
323 * Note that if the hardware write-protect pin is pulled high, the whole
324 * chip is normally write protected. But there are plenty of product
325 * variants here, including OTP fuses and partial chip protect.
326 *
327 * We only use page mode writes; the alternative is sloooow. These routines
328 * write at most one page.
329 */
330
331static size_t at24_adjust_write_count(struct at24_data *at24,
332				      unsigned int offset, size_t count)
333{
334	unsigned int next_page;
335
336	/* write_max is at most a page */
337	if (count > at24->write_max)
338		count = at24->write_max;
339
340	/* Never roll over backwards, to the start of this page */
341	next_page = roundup(offset + 1, at24->page_size);
342	if (offset + count > next_page)
343		count = next_page - offset;
344
345	return count;
346}
347
348static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf,
349				 unsigned int offset, size_t count)
350{
351	unsigned long timeout, write_time;
352	struct at24_client *at24_client;
353	struct i2c_client *client;
354	struct regmap *regmap;
355	int ret;
356
357	at24_client = at24_translate_offset(at24, &offset);
358	regmap = at24_client->regmap;
359	client = at24_client->client;
360	count = at24_adjust_write_count(at24, offset, count);
 
 
 
 
 
 
 
 
361
362	at24_loop_until_timeout(timeout, write_time) {
363		ret = regmap_bulk_write(regmap, offset, buf, count);
364		dev_dbg(&client->dev, "write %zu@%d --> %d (%ld)\n",
365			count, offset, ret, jiffies);
366		if (!ret)
367			return count;
368	}
 
 
369
370	return -ETIMEDOUT;
371}
372
373static int at24_read(void *priv, unsigned int off, void *val, size_t count)
374{
375	struct at24_data *at24;
376	struct device *dev;
377	char *buf = val;
378	int ret;
379
380	at24 = priv;
381	dev = at24_base_client_dev(at24);
382
383	if (unlikely(!count))
384		return count;
385
386	if (off + count > at24->byte_len)
387		return -EINVAL;
388
389	ret = pm_runtime_get_sync(dev);
390	if (ret < 0) {
391		pm_runtime_put_noidle(dev);
392		return ret;
393	}
394
395	/*
396	 * Read data from chip, protecting against concurrent updates
397	 * from this host, but not from other I2C masters.
398	 */
399	mutex_lock(&at24->lock);
400
401	while (count) {
402		ret = at24_regmap_read(at24, buf, off, count);
403		if (ret < 0) {
404			mutex_unlock(&at24->lock);
405			pm_runtime_put(dev);
406			return ret;
407		}
408		buf += ret;
409		off += ret;
410		count -= ret;
411	}
412
413	mutex_unlock(&at24->lock);
414
415	pm_runtime_put(dev);
416
417	return 0;
418}
419
420static int at24_write(void *priv, unsigned int off, void *val, size_t count)
421{
422	struct at24_data *at24;
423	struct device *dev;
424	char *buf = val;
425	int ret;
426
427	at24 = priv;
428	dev = at24_base_client_dev(at24);
429
430	if (unlikely(!count))
431		return -EINVAL;
432
433	if (off + count > at24->byte_len)
434		return -EINVAL;
435
436	ret = pm_runtime_get_sync(dev);
437	if (ret < 0) {
438		pm_runtime_put_noidle(dev);
439		return ret;
440	}
441
442	/*
443	 * Write data to chip, protecting against concurrent updates
444	 * from this host, but not from other I2C masters.
445	 */
446	mutex_lock(&at24->lock);
447	gpiod_set_value_cansleep(at24->wp_gpio, 0);
448
449	while (count) {
450		ret = at24_regmap_write(at24, buf, off, count);
451		if (ret < 0) {
452			gpiod_set_value_cansleep(at24->wp_gpio, 1);
453			mutex_unlock(&at24->lock);
454			pm_runtime_put(dev);
455			return ret;
456		}
457		buf += ret;
458		off += ret;
459		count -= ret;
460	}
461
462	gpiod_set_value_cansleep(at24->wp_gpio, 1);
463	mutex_unlock(&at24->lock);
464
465	pm_runtime_put(dev);
466
467	return 0;
468}
469
470static void at24_properties_to_pdata(struct device *dev,
471				     struct at24_platform_data *chip)
472{
473	int err;
474	u32 val;
475
476	if (device_property_present(dev, "read-only"))
477		chip->flags |= AT24_FLAG_READONLY;
478	if (device_property_present(dev, "no-read-rollover"))
479		chip->flags |= AT24_FLAG_NO_RDROL;
480
481	err = device_property_read_u32(dev, "size", &val);
482	if (!err)
483		chip->byte_len = val;
484
485	err = device_property_read_u32(dev, "pagesize", &val);
486	if (!err) {
487		chip->page_size = val;
488	} else {
489		/*
490		 * This is slow, but we can't know all eeproms, so we better
491		 * play safe. Specifying custom eeprom-types via platform_data
492		 * is recommended anyhow.
493		 */
494		chip->page_size = 1;
495	}
496}
497
498static int at24_get_pdata(struct device *dev, struct at24_platform_data *pdata)
499{
500	struct device_node *of_node = dev->of_node;
501	const struct at24_chip_data *cdata;
502	const struct i2c_device_id *id;
503	struct at24_platform_data *pd;
504
505	pd = dev_get_platdata(dev);
506	if (pd) {
507		memcpy(pdata, pd, sizeof(*pdata));
508		return 0;
509	}
510
511	id = i2c_match_id(at24_ids, to_i2c_client(dev));
512
513	/*
514	 * The I2C core allows OF nodes compatibles to match against the
515	 * I2C device ID table as a fallback, so check not only if an OF
516	 * node is present but also if it matches an OF device ID entry.
517	 */
518	if (of_node && of_match_device(at24_of_match, dev))
519		cdata = of_device_get_match_data(dev);
520	else if (id)
521		cdata = (void *)id->driver_data;
522	else
523		cdata = acpi_device_get_match_data(dev);
524
525	if (!cdata)
526		return -ENODEV;
 
 
 
 
 
 
 
 
 
 
 
 
 
527
528	pdata->byte_len = cdata->byte_len;
529	pdata->flags = cdata->flags;
530	at24_properties_to_pdata(dev, pdata);
 
 
 
 
 
 
 
 
531
532	return 0;
533}
534
535static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len)
536{
537	if (flags & AT24_FLAG_MAC) {
538		/* EUI-48 starts from 0x9a, EUI-64 from 0x98 */
539		return 0xa0 - byte_len;
540	} else if (flags & AT24_FLAG_SERIAL && flags & AT24_FLAG_ADDR16) {
541		/*
542		 * For 16 bit address pointers, the word address must contain
543		 * a '10' sequence in bits 11 and 10 regardless of the
544		 * intended position of the address pointer.
545		 */
546		return 0x0800;
547	} else if (flags & AT24_FLAG_SERIAL) {
548		/*
549		 * Otherwise the word address must begin with a '10' sequence,
550		 * regardless of the intended address.
551		 */
552		return 0x0080;
553	} else {
554		return 0;
555	}
556}
557
558static int at24_probe(struct i2c_client *client)
559{
560	struct regmap_config regmap_config = { };
561	struct nvmem_config nvmem_config = { };
562	struct at24_platform_data pdata = { };
 
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	size_t at24_size;
569	bool writable;
570	u8 test_byte;
571	int err;
572
573	i2c_fn_i2c = i2c_check_functionality(client->adapter, I2C_FUNC_I2C);
574	i2c_fn_block = i2c_check_functionality(client->adapter,
575					       I2C_FUNC_SMBUS_WRITE_I2C_BLOCK);
576
577	err = at24_get_pdata(dev, &pdata);
 
 
 
 
578	if (err)
579		return err;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
580
581	if (!i2c_fn_i2c && !i2c_fn_block)
582		pdata.page_size = 1;
583
584	if (!pdata.page_size) {
585		dev_err(dev, "page_size must not be 0!\n");
586		return -EINVAL;
587	}
588
589	if (!is_power_of_2(pdata.page_size))
590		dev_warn(dev, "page_size looks suspicious (no power of 2)!\n");
591
592	if (pdata.flags & AT24_FLAG_TAKE8ADDR)
593		num_addresses = 8;
594	else
595		num_addresses =	DIV_ROUND_UP(pdata.byte_len,
596			(pdata.flags & AT24_FLAG_ADDR16) ? 65536 : 256);
 
 
 
597
598	if ((pdata.flags & AT24_FLAG_SERIAL) && (pdata.flags & AT24_FLAG_MAC)) {
599		dev_err(dev,
600			"invalid device data - cannot have both AT24_FLAG_SERIAL & AT24_FLAG_MAC.");
601		return -EINVAL;
602	}
603
604	regmap_config.val_bits = 8;
605	regmap_config.reg_bits = (pdata.flags & AT24_FLAG_ADDR16) ? 16 : 8;
606	regmap_config.disable_locking = true;
607
608	regmap = devm_regmap_init_i2c(client, &regmap_config);
609	if (IS_ERR(regmap))
610		return PTR_ERR(regmap);
611
612	at24_size = sizeof(*at24) + num_addresses * sizeof(struct at24_client);
613	at24 = devm_kzalloc(dev, at24_size, GFP_KERNEL);
614	if (!at24)
615		return -ENOMEM;
616
617	mutex_init(&at24->lock);
618	at24->byte_len = pdata.byte_len;
619	at24->page_size = pdata.page_size;
620	at24->flags = pdata.flags;
621	at24->num_addresses = num_addresses;
622	at24->offset_adj = at24_get_offset_adj(pdata.flags, pdata.byte_len);
623	at24->client[0].client = client;
624	at24->client[0].regmap = regmap;
625
626	at24->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_HIGH);
627	if (IS_ERR(at24->wp_gpio))
628		return PTR_ERR(at24->wp_gpio);
629
630	writable = !(pdata.flags & AT24_FLAG_READONLY);
631	if (writable) {
632		at24->write_max = min_t(unsigned int,
633					pdata.page_size, at24_io_limit);
634		if (!i2c_fn_i2c && at24->write_max > I2C_SMBUS_BLOCK_MAX)
635			at24->write_max = I2C_SMBUS_BLOCK_MAX;
636	}
637
638	/* use dummy devices for multiple-address chips */
639	for (i = 1; i < num_addresses; i++) {
640		at24->client[i].client = i2c_new_dummy(client->adapter,
641						       client->addr + i);
642		if (!at24->client[i].client) {
643			dev_err(dev, "address 0x%02x unavailable\n",
644				client->addr + i);
645			err = -EADDRINUSE;
646			goto err_clients;
647		}
648		at24->client[i].regmap = devm_regmap_init_i2c(
649						at24->client[i].client,
650						&regmap_config);
651		if (IS_ERR(at24->client[i].regmap)) {
652			err = PTR_ERR(at24->client[i].regmap);
653			goto err_clients;
654		}
655	}
656
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
657	i2c_set_clientdata(client, at24);
658
659	/* enable runtime pm */
660	pm_runtime_set_active(dev);
661	pm_runtime_enable(dev);
662
663	/*
664	 * Perform a one-byte test read to verify that the
665	 * chip is functional.
666	 */
667	err = at24_read(at24, 0, &test_byte, 1);
668	pm_runtime_idle(dev);
669	if (err) {
670		err = -ENODEV;
671		goto err_clients;
672	}
673
674	nvmem_config.name = dev_name(dev);
675	nvmem_config.dev = dev;
676	nvmem_config.read_only = !writable;
677	nvmem_config.root_only = true;
678	nvmem_config.owner = THIS_MODULE;
679	nvmem_config.compat = true;
680	nvmem_config.base_dev = dev;
681	nvmem_config.reg_read = at24_read;
682	nvmem_config.reg_write = at24_write;
683	nvmem_config.priv = at24;
684	nvmem_config.stride = 1;
685	nvmem_config.word_size = 1;
686	nvmem_config.size = pdata.byte_len;
687
688	at24->nvmem = nvmem_register(&nvmem_config);
689	if (IS_ERR(at24->nvmem)) {
690		err = PTR_ERR(at24->nvmem);
691		goto err_clients;
692	}
693
694	dev_info(dev, "%u byte %s EEPROM, %s, %u bytes/write\n",
695		 pdata.byte_len, client->name,
696		 writable ? "writable" : "read-only", at24->write_max);
697
698	/* export data to kernel code */
699	if (pdata.setup)
700		pdata.setup(at24->nvmem, pdata.context);
701
702	return 0;
703
704err_clients:
705	for (i = 1; i < num_addresses; i++)
706		if (at24->client[i].client)
707			i2c_unregister_device(at24->client[i].client);
708
709	pm_runtime_disable(dev);
710
711	return err;
712}
713
714static int at24_remove(struct i2c_client *client)
715{
716	struct at24_data *at24;
717	int i;
718
719	at24 = i2c_get_clientdata(client);
720
721	nvmem_unregister(at24->nvmem);
722
723	for (i = 1; i < at24->num_addresses; i++)
724		i2c_unregister_device(at24->client[i].client);
725
726	pm_runtime_disable(&client->dev);
727	pm_runtime_set_suspended(&client->dev);
728
729	return 0;
730}
731
732static struct i2c_driver at24_driver = {
733	.driver = {
734		.name = "at24",
735		.of_match_table = at24_of_match,
736		.acpi_match_table = ACPI_PTR(at24_acpi_ids),
737	},
738	.probe_new = at24_probe,
739	.remove = at24_remove,
740	.id_table = at24_ids,
741};
742
743static int __init at24_init(void)
744{
745	if (!at24_io_limit) {
746		pr_err("at24: at24_io_limit must not be 0!\n");
747		return -EINVAL;
748	}
749
750	at24_io_limit = rounddown_pow_of_two(at24_io_limit);
751	return i2c_add_driver(&at24_driver);
752}
753module_init(at24_init);
754
755static void __exit at24_exit(void)
756{
757	i2c_del_driver(&at24_driver);
758}
759module_exit(at24_exit);
760
761MODULE_DESCRIPTION("Driver for most I2C EEPROMs");
762MODULE_AUTHOR("David Brownell and Wolfram Sang");
763MODULE_LICENSE("GPL");