summaryrefslogtreecommitdiff
path: root/drivers/misc/eeprom/eeprom_93xx46.c
blob: 78e55b501c94816a51b6ed7186c8473815b13689 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
/*
 * Driver for 93xx46 EEPROMs
 *
 * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/delay.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
#include <linux/eeprom_93xx46.h>

#define OP_START	0x4
#define OP_WRITE	(OP_START | 0x1)
#define OP_READ		(OP_START | 0x2)
#define ADDR_EWDS	0x00
#define ADDR_ERAL	0x20
#define ADDR_EWEN	0x30

struct eeprom_93xx46_dev {
	struct spi_device *spi;
	struct eeprom_93xx46_platform_data *pdata;
	struct bin_attribute bin;
	struct mutex lock;
	int addrlen;
};

static ssize_t
eeprom_93xx46_bin_read(struct file *filp, struct kobject *kobj,
		       struct bin_attribute *bin_attr,
		       char *buf, loff_t off, size_t count)
{
	struct eeprom_93xx46_dev *edev;
	struct device *dev;
	struct spi_message m;
	struct spi_transfer t[2];
	int bits, ret;
	u16 cmd_addr;

	dev = container_of(kobj, struct device, kobj);
	edev = dev_get_drvdata(dev);

	if (unlikely(off >= edev->bin.size))
		return 0;
	if ((off + count) > edev->bin.size)
		count = edev->bin.size - off;
	if (unlikely(!count))
		return count;

	cmd_addr = OP_READ << edev->addrlen;

	if (edev->addrlen == 7) {
		cmd_addr |= off & 0x7f;
		bits = 10;
	} else {
		cmd_addr |= off & 0x3f;
		bits = 9;
	}

	dev_dbg(&edev->spi->dev, "read cmd 0x%x, %d Hz\n",
		cmd_addr, edev->spi->max_speed_hz);

	spi_message_init(&m);
	memset(t, 0, sizeof(t));

	t[0].tx_buf = (char *)&cmd_addr;
	t[0].len = 2;
	t[0].bits_per_word = bits;
	spi_message_add_tail(&t[0], &m);

	t[1].rx_buf = buf;
	t[1].len = count;
	t[1].bits_per_word = 8;
	spi_message_add_tail(&t[1], &m);

	mutex_lock(&edev->lock);

	if (edev->pdata->prepare)
		edev->pdata->prepare(edev);

	ret = spi_sync(edev->spi, &m);
	/* have to wait at least Tcsl ns */
	ndelay(250);
	if (ret) {
		dev_err(&edev->spi->dev, "read %zu bytes at %d: err. %d\n",
			count, (int)off, ret);
	}

	if (edev->pdata->finish)
		edev->pdata->finish(edev);

	mutex_unlock(&edev->lock);
	return ret ? : count;
}

static int eeprom_93xx46_ew(struct eeprom_93xx46_dev *edev, int is_on)
{
	struct spi_message m;
	struct spi_transfer t;
	int bits, ret;
	u16 cmd_addr;

	cmd_addr = OP_START << edev->addrlen;
	if (edev->addrlen == 7) {
		cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS) << 1;
		bits = 10;
	} else {
		cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS);
		bits = 9;
	}

	dev_dbg(&edev->spi->dev, "ew cmd 0x%04x\n", cmd_addr);

	spi_message_init(&m);
	memset(&t, 0, sizeof(t));

	t.tx_buf = &cmd_addr;
	t.len = 2;
	t.bits_per_word = bits;
	spi_message_add_tail(&t, &m);

	mutex_lock(&edev->lock);

	if (edev->pdata->prepare)
		edev->pdata->prepare(edev);

	ret = spi_sync(edev->spi, &m);
	/* have to wait at least Tcsl ns */
	ndelay(250);
	if (ret)
		dev_err(&edev->spi->dev, "erase/write %sable error %d\n",
			is_on ? "en" : "dis", ret);

	if (edev->pdata->finish)
		edev->pdata->finish(edev);

	mutex_unlock(&edev->lock);
	return ret;
}

static ssize_t
eeprom_93xx46_write_word(struct eeprom_93xx46_dev *edev,
			 const char *buf, unsigned off)
{
	struct spi_message m;
	struct spi_transfer t[2];
	int bits, data_len, ret;
	u16 cmd_addr;

	cmd_addr = OP_WRITE << edev->addrlen;

	if (edev->addrlen == 7) {
		cmd_addr |= off & 0x7f;
		bits = 10;
		data_len = 1;
	} else {
		cmd_addr |= off & 0x3f;
		bits = 9;
		data_len = 2;
	}

	dev_dbg(&edev->spi->dev, "write cmd 0x%x\n", cmd_addr);

	spi_message_init(&m);
	memset(t, 0, sizeof(t));

	t[0].tx_buf = (char *)&cmd_addr;
	t[0].len = 2;
	t[0].bits_per_word = bits;
	spi_message_add_tail(&t[0], &m);

	t[1].tx_buf = buf;
	t[1].len = data_len;
	t[1].bits_per_word = 8;
	spi_message_add_tail(&t[1], &m);

	ret = spi_sync(edev->spi, &m);
	/* have to wait program cycle time Twc ms */
	mdelay(6);
	return ret;
}

static ssize_t
eeprom_93xx46_bin_write(struct file *filp, struct kobject *kobj,
			struct bin_attribute *bin_attr,
			char *buf, loff_t off, size_t count)
{
	struct eeprom_93xx46_dev *edev;
	struct device *dev;
	int i, ret, step = 1;

	dev = container_of(kobj, struct device, kobj);
	edev = dev_get_drvdata(dev);

	if (unlikely(off >= edev->bin.size))
		return -EFBIG;
	if ((off + count) > edev->bin.size)
		count = edev->bin.size - off;
	if (unlikely(!count))
		return count;

	/* only write even number of bytes on 16-bit devices */
	if (edev->addrlen == 6) {
		step = 2;
		count &= ~1;
	}

	/* erase/write enable */
	ret = eeprom_93xx46_ew(edev, 1);
	if (ret)
		return ret;

	mutex_lock(&edev->lock);

	if (edev->pdata->prepare)
		edev->pdata->prepare(edev);

	for (i = 0; i < count; i += step) {
		ret = eeprom_93xx46_write_word(edev, &buf[i], off + i);
		if (ret) {
			dev_err(&edev->spi->dev, "write failed at %d: %d\n",
				(int)off + i, ret);
			break;
		}
	}

	if (edev->pdata->finish)
		edev->pdata->finish(edev);

	mutex_unlock(&edev->lock);

	/* erase/write disable */
	eeprom_93xx46_ew(edev, 0);
	return ret ? : count;
}

static int eeprom_93xx46_eral(struct eeprom_93xx46_dev *edev)
{
	struct eeprom_93xx46_platform_data *pd = edev->pdata;
	struct spi_message m;
	struct spi_transfer t;
	int bits, ret;
	u16 cmd_addr;

	cmd_addr = OP_START << edev->addrlen;
	if (edev->addrlen == 7) {
		cmd_addr |= ADDR_ERAL << 1;
		bits = 10;
	} else {
		cmd_addr |= ADDR_ERAL;
		bits = 9;
	}

	spi_message_init(&m);
	memset(&t, 0, sizeof(t));

	t.tx_buf = &cmd_addr;
	t.len = 2;
	t.bits_per_word = bits;
	spi_message_add_tail(&t, &m);

	mutex_lock(&edev->lock);

	if (edev->pdata->prepare)
		edev->pdata->prepare(edev);

	ret = spi_sync(edev->spi, &m);
	if (ret)
		dev_err(&edev->spi->dev, "erase error %d\n", ret);
	/* have to wait erase cycle time Tec ms */
	mdelay(6);

	if (pd->finish)
		pd->finish(edev);

	mutex_unlock(&edev->lock);
	return ret;
}

static ssize_t eeprom_93xx46_store_erase(struct device *dev,
					 struct device_attribute *attr,
					 const char *buf, size_t count)
{
	struct eeprom_93xx46_dev *edev = dev_get_drvdata(dev);
	int erase = 0, ret;

	sscanf(buf, "%d", &erase);
	if (erase) {
		ret = eeprom_93xx46_ew(edev, 1);
		if (ret)
			return ret;
		ret = eeprom_93xx46_eral(edev);
		if (ret)
			return ret;
		ret = eeprom_93xx46_ew(edev, 0);
		if (ret)
			return ret;
	}
	return count;
}
static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase);

static int eeprom_93xx46_probe(struct spi_device *spi)
{
	struct eeprom_93xx46_platform_data *pd;
	struct eeprom_93xx46_dev *edev;
	int err;

	pd = spi->dev.platform_data;
	if (!pd) {
		dev_err(&spi->dev, "missing platform data\n");
		return -ENODEV;
	}

	edev = kzalloc(sizeof(*edev), GFP_KERNEL);
	if (!edev)
		return -ENOMEM;

	if (pd->flags & EE_ADDR8)
		edev->addrlen = 7;
	else if (pd->flags & EE_ADDR16)
		edev->addrlen = 6;
	else {
		dev_err(&spi->dev, "unspecified address type\n");
		err = -EINVAL;
		goto fail;
	}

	mutex_init(&edev->lock);

	edev->spi = spi_dev_get(spi);
	edev->pdata = pd;

	sysfs_bin_attr_init(&edev->bin);
	edev->bin.attr.name = "eeprom";
	edev->bin.attr.mode = S_IRUSR;
	edev->bin.read = eeprom_93xx46_bin_read;
	edev->bin.size = 128;
	if (!(pd->flags & EE_READONLY)) {
		edev->bin.write = eeprom_93xx46_bin_write;
		edev->bin.attr.mode |= S_IWUSR;
	}

	err = sysfs_create_bin_file(&spi->dev.kobj, &edev->bin);
	if (err)
		goto fail;

	dev_info(&spi->dev, "%d-bit eeprom %s\n",
		(pd->flags & EE_ADDR8) ? 8 : 16,
		(pd->flags & EE_READONLY) ? "(readonly)" : "");

	if (!(pd->flags & EE_READONLY)) {
		if (device_create_file(&spi->dev, &dev_attr_erase))
			dev_err(&spi->dev, "can't create erase interface\n");
	}

	spi_set_drvdata(spi, edev);
	return 0;
fail:
	kfree(edev);
	return err;
}

static int eeprom_93xx46_remove(struct spi_device *spi)
{
	struct eeprom_93xx46_dev *edev = spi_get_drvdata(spi);

	if (!(edev->pdata->flags & EE_READONLY))
		device_remove_file(&spi->dev, &dev_attr_erase);

	sysfs_remove_bin_file(&spi->dev.kobj, &edev->bin);
	kfree(edev);
	return 0;
}

static struct spi_driver eeprom_93xx46_driver = {
	.driver = {
		.name	= "93xx46",
		.owner	= THIS_MODULE,
	},
	.probe		= eeprom_93xx46_probe,
	.remove		= eeprom_93xx46_remove,
};

module_spi_driver(eeprom_93xx46_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Driver for 93xx46 EEPROMs");
MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>");
MODULE_ALIAS("spi:93xx46");