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8#include <linux/delay.h>
9#include <linux/device.h>
10#include <linux/gpio/consumer.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/mutex.h>
14#include <linux/of.h>
15#include <linux/of_device.h>
16#include <linux/of_gpio.h>
17#include <linux/slab.h>
18#include <linux/spi/spi.h>
19#include <linux/nvmem-provider.h>
20#include <linux/eeprom_93xx46.h>
21
22#define OP_START 0x4
23#define OP_WRITE (OP_START | 0x1)
24#define OP_READ (OP_START | 0x2)
25#define ADDR_EWDS 0x00
26#define ADDR_ERAL 0x20
27#define ADDR_EWEN 0x30
28
29struct eeprom_93xx46_devtype_data {
30 unsigned int quirks;
31};
32
33static const struct eeprom_93xx46_devtype_data atmel_at93c46d_data = {
34 .quirks = EEPROM_93XX46_QUIRK_SINGLE_WORD_READ |
35 EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH,
36};
37
38struct eeprom_93xx46_dev {
39 struct spi_device *spi;
40 struct eeprom_93xx46_platform_data *pdata;
41 struct mutex lock;
42 struct nvmem_config nvmem_config;
43 struct nvmem_device *nvmem;
44 int addrlen;
45 int size;
46};
47
48static inline bool has_quirk_single_word_read(struct eeprom_93xx46_dev *edev)
49{
50 return edev->pdata->quirks & EEPROM_93XX46_QUIRK_SINGLE_WORD_READ;
51}
52
53static inline bool has_quirk_instruction_length(struct eeprom_93xx46_dev *edev)
54{
55 return edev->pdata->quirks & EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH;
56}
57
58static int eeprom_93xx46_read(void *priv, unsigned int off,
59 void *val, size_t count)
60{
61 struct eeprom_93xx46_dev *edev = priv;
62 char *buf = val;
63 int err = 0;
64
65 if (unlikely(off >= edev->size))
66 return 0;
67 if ((off + count) > edev->size)
68 count = edev->size - off;
69 if (unlikely(!count))
70 return count;
71
72 mutex_lock(&edev->lock);
73
74 if (edev->pdata->prepare)
75 edev->pdata->prepare(edev);
76
77 while (count) {
78 struct spi_message m;
79 struct spi_transfer t[2] = { { 0 } };
80 u16 cmd_addr = OP_READ << edev->addrlen;
81 size_t nbytes = count;
82 int bits;
83
84 if (edev->addrlen == 7) {
85 cmd_addr |= off & 0x7f;
86 bits = 10;
87 if (has_quirk_single_word_read(edev))
88 nbytes = 1;
89 } else {
90 cmd_addr |= (off >> 1) & 0x3f;
91 bits = 9;
92 if (has_quirk_single_word_read(edev))
93 nbytes = 2;
94 }
95
96 dev_dbg(&edev->spi->dev, "read cmd 0x%x, %d Hz\n",
97 cmd_addr, edev->spi->max_speed_hz);
98
99 spi_message_init(&m);
100
101 t[0].tx_buf = (char *)&cmd_addr;
102 t[0].len = 2;
103 t[0].bits_per_word = bits;
104 spi_message_add_tail(&t[0], &m);
105
106 t[1].rx_buf = buf;
107 t[1].len = count;
108 t[1].bits_per_word = 8;
109 spi_message_add_tail(&t[1], &m);
110
111 err = spi_sync(edev->spi, &m);
112
113 ndelay(250);
114
115 if (err) {
116 dev_err(&edev->spi->dev, "read %zu bytes at %d: err. %d\n",
117 nbytes, (int)off, err);
118 break;
119 }
120
121 buf += nbytes;
122 off += nbytes;
123 count -= nbytes;
124 }
125
126 if (edev->pdata->finish)
127 edev->pdata->finish(edev);
128
129 mutex_unlock(&edev->lock);
130
131 return err;
132}
133
134static int eeprom_93xx46_ew(struct eeprom_93xx46_dev *edev, int is_on)
135{
136 struct spi_message m;
137 struct spi_transfer t;
138 int bits, ret;
139 u16 cmd_addr;
140
141 cmd_addr = OP_START << edev->addrlen;
142 if (edev->addrlen == 7) {
143 cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS) << 1;
144 bits = 10;
145 } else {
146 cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS);
147 bits = 9;
148 }
149
150 if (has_quirk_instruction_length(edev)) {
151 cmd_addr <<= 2;
152 bits += 2;
153 }
154
155 dev_dbg(&edev->spi->dev, "ew%s cmd 0x%04x, %d bits\n",
156 is_on ? "en" : "ds", cmd_addr, bits);
157
158 spi_message_init(&m);
159 memset(&t, 0, sizeof(t));
160
161 t.tx_buf = &cmd_addr;
162 t.len = 2;
163 t.bits_per_word = bits;
164 spi_message_add_tail(&t, &m);
165
166 mutex_lock(&edev->lock);
167
168 if (edev->pdata->prepare)
169 edev->pdata->prepare(edev);
170
171 ret = spi_sync(edev->spi, &m);
172
173 ndelay(250);
174 if (ret)
175 dev_err(&edev->spi->dev, "erase/write %sable error %d\n",
176 is_on ? "en" : "dis", ret);
177
178 if (edev->pdata->finish)
179 edev->pdata->finish(edev);
180
181 mutex_unlock(&edev->lock);
182 return ret;
183}
184
185static ssize_t
186eeprom_93xx46_write_word(struct eeprom_93xx46_dev *edev,
187 const char *buf, unsigned off)
188{
189 struct spi_message m;
190 struct spi_transfer t[2];
191 int bits, data_len, ret;
192 u16 cmd_addr;
193
194 cmd_addr = OP_WRITE << edev->addrlen;
195
196 if (edev->addrlen == 7) {
197 cmd_addr |= off & 0x7f;
198 bits = 10;
199 data_len = 1;
200 } else {
201 cmd_addr |= (off >> 1) & 0x3f;
202 bits = 9;
203 data_len = 2;
204 }
205
206 dev_dbg(&edev->spi->dev, "write cmd 0x%x\n", cmd_addr);
207
208 spi_message_init(&m);
209 memset(t, 0, sizeof(t));
210
211 t[0].tx_buf = (char *)&cmd_addr;
212 t[0].len = 2;
213 t[0].bits_per_word = bits;
214 spi_message_add_tail(&t[0], &m);
215
216 t[1].tx_buf = buf;
217 t[1].len = data_len;
218 t[1].bits_per_word = 8;
219 spi_message_add_tail(&t[1], &m);
220
221 ret = spi_sync(edev->spi, &m);
222
223 mdelay(6);
224 return ret;
225}
226
227static int eeprom_93xx46_write(void *priv, unsigned int off,
228 void *val, size_t count)
229{
230 struct eeprom_93xx46_dev *edev = priv;
231 char *buf = val;
232 int i, ret, step = 1;
233
234 if (unlikely(off >= edev->size))
235 return -EFBIG;
236 if ((off + count) > edev->size)
237 count = edev->size - off;
238 if (unlikely(!count))
239 return count;
240
241
242 if (edev->addrlen == 6) {
243 step = 2;
244 count &= ~1;
245 }
246
247
248 ret = eeprom_93xx46_ew(edev, 1);
249 if (ret)
250 return ret;
251
252 mutex_lock(&edev->lock);
253
254 if (edev->pdata->prepare)
255 edev->pdata->prepare(edev);
256
257 for (i = 0; i < count; i += step) {
258 ret = eeprom_93xx46_write_word(edev, &buf[i], off + i);
259 if (ret) {
260 dev_err(&edev->spi->dev, "write failed at %d: %d\n",
261 (int)off + i, ret);
262 break;
263 }
264 }
265
266 if (edev->pdata->finish)
267 edev->pdata->finish(edev);
268
269 mutex_unlock(&edev->lock);
270
271
272 eeprom_93xx46_ew(edev, 0);
273 return ret;
274}
275
276static int eeprom_93xx46_eral(struct eeprom_93xx46_dev *edev)
277{
278 struct eeprom_93xx46_platform_data *pd = edev->pdata;
279 struct spi_message m;
280 struct spi_transfer t;
281 int bits, ret;
282 u16 cmd_addr;
283
284 cmd_addr = OP_START << edev->addrlen;
285 if (edev->addrlen == 7) {
286 cmd_addr |= ADDR_ERAL << 1;
287 bits = 10;
288 } else {
289 cmd_addr |= ADDR_ERAL;
290 bits = 9;
291 }
292
293 if (has_quirk_instruction_length(edev)) {
294 cmd_addr <<= 2;
295 bits += 2;
296 }
297
298 dev_dbg(&edev->spi->dev, "eral cmd 0x%04x, %d bits\n", cmd_addr, bits);
299
300 spi_message_init(&m);
301 memset(&t, 0, sizeof(t));
302
303 t.tx_buf = &cmd_addr;
304 t.len = 2;
305 t.bits_per_word = bits;
306 spi_message_add_tail(&t, &m);
307
308 mutex_lock(&edev->lock);
309
310 if (edev->pdata->prepare)
311 edev->pdata->prepare(edev);
312
313 ret = spi_sync(edev->spi, &m);
314 if (ret)
315 dev_err(&edev->spi->dev, "erase error %d\n", ret);
316
317 mdelay(6);
318
319 if (pd->finish)
320 pd->finish(edev);
321
322 mutex_unlock(&edev->lock);
323 return ret;
324}
325
326static ssize_t eeprom_93xx46_store_erase(struct device *dev,
327 struct device_attribute *attr,
328 const char *buf, size_t count)
329{
330 struct eeprom_93xx46_dev *edev = dev_get_drvdata(dev);
331 int erase = 0, ret;
332
333 sscanf(buf, "%d", &erase);
334 if (erase) {
335 ret = eeprom_93xx46_ew(edev, 1);
336 if (ret)
337 return ret;
338 ret = eeprom_93xx46_eral(edev);
339 if (ret)
340 return ret;
341 ret = eeprom_93xx46_ew(edev, 0);
342 if (ret)
343 return ret;
344 }
345 return count;
346}
347static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase);
348
349static void select_assert(void *context)
350{
351 struct eeprom_93xx46_dev *edev = context;
352
353 gpiod_set_value_cansleep(edev->pdata->select, 1);
354}
355
356static void select_deassert(void *context)
357{
358 struct eeprom_93xx46_dev *edev = context;
359
360 gpiod_set_value_cansleep(edev->pdata->select, 0);
361}
362
363static const struct of_device_id eeprom_93xx46_of_table[] = {
364 { .compatible = "eeprom-93xx46", },
365 { .compatible = "atmel,at93c46d", .data = &atmel_at93c46d_data, },
366 {}
367};
368MODULE_DEVICE_TABLE(of, eeprom_93xx46_of_table);
369
370static int eeprom_93xx46_probe_dt(struct spi_device *spi)
371{
372 const struct of_device_id *of_id =
373 of_match_device(eeprom_93xx46_of_table, &spi->dev);
374 struct device_node *np = spi->dev.of_node;
375 struct eeprom_93xx46_platform_data *pd;
376 u32 tmp;
377 int ret;
378
379 pd = devm_kzalloc(&spi->dev, sizeof(*pd), GFP_KERNEL);
380 if (!pd)
381 return -ENOMEM;
382
383 ret = of_property_read_u32(np, "data-size", &tmp);
384 if (ret < 0) {
385 dev_err(&spi->dev, "data-size property not found\n");
386 return ret;
387 }
388
389 if (tmp == 8) {
390 pd->flags |= EE_ADDR8;
391 } else if (tmp == 16) {
392 pd->flags |= EE_ADDR16;
393 } else {
394 dev_err(&spi->dev, "invalid data-size (%d)\n", tmp);
395 return -EINVAL;
396 }
397
398 if (of_property_read_bool(np, "read-only"))
399 pd->flags |= EE_READONLY;
400
401 pd->select = devm_gpiod_get_optional(&spi->dev, "select",
402 GPIOD_OUT_LOW);
403 if (IS_ERR(pd->select))
404 return PTR_ERR(pd->select);
405
406 pd->prepare = select_assert;
407 pd->finish = select_deassert;
408 gpiod_direction_output(pd->select, 0);
409
410 if (of_id->data) {
411 const struct eeprom_93xx46_devtype_data *data = of_id->data;
412
413 pd->quirks = data->quirks;
414 }
415
416 spi->dev.platform_data = pd;
417
418 return 0;
419}
420
421static int eeprom_93xx46_probe(struct spi_device *spi)
422{
423 struct eeprom_93xx46_platform_data *pd;
424 struct eeprom_93xx46_dev *edev;
425 int err;
426
427 if (spi->dev.of_node) {
428 err = eeprom_93xx46_probe_dt(spi);
429 if (err < 0)
430 return err;
431 }
432
433 pd = spi->dev.platform_data;
434 if (!pd) {
435 dev_err(&spi->dev, "missing platform data\n");
436 return -ENODEV;
437 }
438
439 edev = devm_kzalloc(&spi->dev, sizeof(*edev), GFP_KERNEL);
440 if (!edev)
441 return -ENOMEM;
442
443 if (pd->flags & EE_ADDR8)
444 edev->addrlen = 7;
445 else if (pd->flags & EE_ADDR16)
446 edev->addrlen = 6;
447 else {
448 dev_err(&spi->dev, "unspecified address type\n");
449 return -EINVAL;
450 }
451
452 mutex_init(&edev->lock);
453
454 edev->spi = spi;
455 edev->pdata = pd;
456
457 edev->size = 128;
458 edev->nvmem_config.name = dev_name(&spi->dev);
459 edev->nvmem_config.dev = &spi->dev;
460 edev->nvmem_config.read_only = pd->flags & EE_READONLY;
461 edev->nvmem_config.root_only = true;
462 edev->nvmem_config.owner = THIS_MODULE;
463 edev->nvmem_config.compat = true;
464 edev->nvmem_config.base_dev = &spi->dev;
465 edev->nvmem_config.reg_read = eeprom_93xx46_read;
466 edev->nvmem_config.reg_write = eeprom_93xx46_write;
467 edev->nvmem_config.priv = edev;
468 edev->nvmem_config.stride = 4;
469 edev->nvmem_config.word_size = 1;
470 edev->nvmem_config.size = edev->size;
471
472 edev->nvmem = devm_nvmem_register(&spi->dev, &edev->nvmem_config);
473 if (IS_ERR(edev->nvmem))
474 return PTR_ERR(edev->nvmem);
475
476 dev_info(&spi->dev, "%d-bit eeprom %s\n",
477 (pd->flags & EE_ADDR8) ? 8 : 16,
478 (pd->flags & EE_READONLY) ? "(readonly)" : "");
479
480 if (!(pd->flags & EE_READONLY)) {
481 if (device_create_file(&spi->dev, &dev_attr_erase))
482 dev_err(&spi->dev, "can't create erase interface\n");
483 }
484
485 spi_set_drvdata(spi, edev);
486 return 0;
487}
488
489static int eeprom_93xx46_remove(struct spi_device *spi)
490{
491 struct eeprom_93xx46_dev *edev = spi_get_drvdata(spi);
492
493 if (!(edev->pdata->flags & EE_READONLY))
494 device_remove_file(&spi->dev, &dev_attr_erase);
495
496 return 0;
497}
498
499static struct spi_driver eeprom_93xx46_driver = {
500 .driver = {
501 .name = "93xx46",
502 .of_match_table = of_match_ptr(eeprom_93xx46_of_table),
503 },
504 .probe = eeprom_93xx46_probe,
505 .remove = eeprom_93xx46_remove,
506};
507
508module_spi_driver(eeprom_93xx46_driver);
509
510MODULE_LICENSE("GPL");
511MODULE_DESCRIPTION("Driver for 93xx46 EEPROMs");
512MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>");
513MODULE_ALIAS("spi:93xx46");
514
