summaryrefslogtreecommitdiffstats
path: root/drivers/iio/dac/mcp4725.c
blob: bb4b85a7b95b6f1fe38b6f694c61bf85bc876129 (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
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
// SPDX-License-Identifier: GPL-2.0-only
/*
 * mcp4725.c - Support for Microchip MCP4725/6
 *
 * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
 *
 * Based on max517 by Roland Stigge <stigge@antcom.de>
 *
 * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
 * (7-bit I2C slave address 0x60, the three LSBs can be configured in
 * hardware)
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/regulator/consumer.h>
#include <linux/mod_devicetable.h>
#include <linux/property.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

#include <linux/iio/dac/mcp4725.h>

#define MCP4725_DRV_NAME "mcp4725"

#define MCP472X_REF_VDD			0x00
#define MCP472X_REF_VREF_UNBUFFERED	0x02
#define MCP472X_REF_VREF_BUFFERED	0x03

struct mcp4725_data {
	struct i2c_client *client;
	int id;
	unsigned ref_mode;
	bool vref_buffered;
	u16 dac_value;
	bool powerdown;
	unsigned powerdown_mode;
	struct regulator *vdd_reg;
	struct regulator *vref_reg;
};

static int mcp4725_suspend(struct device *dev)
{
	struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
		to_i2c_client(dev)));
	u8 outbuf[2];

	outbuf[0] = (data->powerdown_mode + 1) << 4;
	outbuf[1] = 0;
	data->powerdown = true;

	return i2c_master_send(data->client, outbuf, 2);
}

static int mcp4725_resume(struct device *dev)
{
	struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
		to_i2c_client(dev)));
	u8 outbuf[2];

	/* restore previous DAC value */
	outbuf[0] = (data->dac_value >> 8) & 0xf;
	outbuf[1] = data->dac_value & 0xff;
	data->powerdown = false;

	return i2c_master_send(data->client, outbuf, 2);
}
static DEFINE_SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend,
				mcp4725_resume);

static ssize_t mcp4725_store_eeprom(struct device *dev,
	struct device_attribute *attr, const char *buf, size_t len)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct mcp4725_data *data = iio_priv(indio_dev);
	int tries = 20;
	u8 inoutbuf[3];
	bool state;
	int ret;

	ret = kstrtobool(buf, &state);
	if (ret < 0)
		return ret;

	if (!state)
		return 0;

	inoutbuf[0] = 0x60; /* write EEPROM */
	inoutbuf[0] |= data->ref_mode << 3;
	inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
	inoutbuf[1] = data->dac_value >> 4;
	inoutbuf[2] = (data->dac_value & 0xf) << 4;

	ret = i2c_master_send(data->client, inoutbuf, 3);
	if (ret < 0)
		return ret;
	else if (ret != 3)
		return -EIO;

	/* wait for write complete, takes up to 50ms */
	while (tries--) {
		msleep(20);
		ret = i2c_master_recv(data->client, inoutbuf, 3);
		if (ret < 0)
			return ret;
		else if (ret != 3)
			return -EIO;

		if (inoutbuf[0] & 0x80)
			break;
	}

	if (tries < 0) {
		dev_err(&data->client->dev,
			"mcp4725_store_eeprom() failed, incomplete\n");
		return -EIO;
	}

	return len;
}

static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);

static struct attribute *mcp4725_attributes[] = {
	&iio_dev_attr_store_eeprom.dev_attr.attr,
	NULL,
};

static const struct attribute_group mcp4725_attribute_group = {
	.attrs = mcp4725_attributes,
};

static const char * const mcp4725_powerdown_modes[] = {
	"1kohm_to_gnd",
	"100kohm_to_gnd",
	"500kohm_to_gnd"
};

static const char * const mcp4726_powerdown_modes[] = {
	"1kohm_to_gnd",
	"125kohm_to_gnd",
	"640kohm_to_gnd"
};

static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan)
{
	struct mcp4725_data *data = iio_priv(indio_dev);

	return data->powerdown_mode;
}

static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan, unsigned mode)
{
	struct mcp4725_data *data = iio_priv(indio_dev);

	data->powerdown_mode = mode;

	return 0;
}

static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
{
	struct mcp4725_data *data = iio_priv(indio_dev);

	return sysfs_emit(buf, "%d\n", data->powerdown);
}

static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
	 uintptr_t private, const struct iio_chan_spec *chan,
	 const char *buf, size_t len)
{
	struct mcp4725_data *data = iio_priv(indio_dev);
	bool state;
	int ret;

	ret = kstrtobool(buf, &state);
	if (ret)
		return ret;

	if (state)
		ret = mcp4725_suspend(&data->client->dev);
	else
		ret = mcp4725_resume(&data->client->dev);
	if (ret < 0)
		return ret;

	return len;
}

enum chip_id {
	MCP4725,
	MCP4726,
};

static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
	[MCP4725] = {
		.items = mcp4725_powerdown_modes,
		.num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
		.get = mcp4725_get_powerdown_mode,
		.set = mcp4725_set_powerdown_mode,
	},
	[MCP4726] = {
		.items = mcp4726_powerdown_modes,
		.num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
		.get = mcp4725_get_powerdown_mode,
		.set = mcp4725_set_powerdown_mode,
	},
};

static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
	{
		.name = "powerdown",
		.read = mcp4725_read_powerdown,
		.write = mcp4725_write_powerdown,
		.shared = IIO_SEPARATE,
	},
	IIO_ENUM("powerdown_mode", IIO_SEPARATE,
			&mcp472x_powerdown_mode_enum[MCP4725]),
	IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
			   &mcp472x_powerdown_mode_enum[MCP4725]),
	{ },
};

static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
	{
		.name = "powerdown",
		.read = mcp4725_read_powerdown,
		.write = mcp4725_write_powerdown,
		.shared = IIO_SEPARATE,
	},
	IIO_ENUM("powerdown_mode", IIO_SEPARATE,
			&mcp472x_powerdown_mode_enum[MCP4726]),
	IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
			   &mcp472x_powerdown_mode_enum[MCP4726]),
	{ },
};

static const struct iio_chan_spec mcp472x_channel[] = {
	[MCP4725] = {
		.type		= IIO_VOLTAGE,
		.indexed	= 1,
		.output		= 1,
		.channel	= 0,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
		.ext_info	= mcp4725_ext_info,
	},
	[MCP4726] = {
		.type		= IIO_VOLTAGE,
		.indexed	= 1,
		.output		= 1,
		.channel	= 0,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
		.ext_info	= mcp4726_ext_info,
	},
};

static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
{
	struct mcp4725_data *data = iio_priv(indio_dev);
	u8 outbuf[2];
	int ret;

	if (val >= (1 << 12) || val < 0)
		return -EINVAL;

	outbuf[0] = (val >> 8) & 0xf;
	outbuf[1] = val & 0xff;

	ret = i2c_master_send(data->client, outbuf, 2);
	if (ret < 0)
		return ret;
	else if (ret != 2)
		return -EIO;
	else
		return 0;
}

static int mcp4726_set_cfg(struct iio_dev *indio_dev)
{
	struct mcp4725_data *data = iio_priv(indio_dev);
	u8 outbuf[3];
	int ret;

	outbuf[0] = 0x40;
	outbuf[0] |= data->ref_mode << 3;
	if (data->powerdown)
		outbuf[0] |= data->powerdown << 1;
	outbuf[1] = data->dac_value >> 4;
	outbuf[2] = (data->dac_value & 0xf) << 4;

	ret = i2c_master_send(data->client, outbuf, 3);
	if (ret < 0)
		return ret;
	else if (ret != 3)
		return -EIO;
	else
		return 0;
}

static int mcp4725_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int *val, int *val2, long mask)
{
	struct mcp4725_data *data = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		*val = data->dac_value;
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		if (data->ref_mode == MCP472X_REF_VDD)
			ret = regulator_get_voltage(data->vdd_reg);
		else
			ret = regulator_get_voltage(data->vref_reg);

		if (ret < 0)
			return ret;

		*val = ret / 1000;
		*val2 = 12;
		return IIO_VAL_FRACTIONAL_LOG2;
	}
	return -EINVAL;
}

static int mcp4725_write_raw(struct iio_dev *indio_dev,
			       struct iio_chan_spec const *chan,
			       int val, int val2, long mask)
{
	struct mcp4725_data *data = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = mcp4725_set_value(indio_dev, val);
		data->dac_value = val;
		break;
	default:
		ret = -EINVAL;
		break;
	}

	return ret;
}

static const struct iio_info mcp4725_info = {
	.read_raw = mcp4725_read_raw,
	.write_raw = mcp4725_write_raw,
	.attrs = &mcp4725_attribute_group,
};

static int mcp4725_probe_dt(struct device *dev,
			    struct mcp4725_platform_data *pdata)
{
	/* check if is the vref-supply defined */
	pdata->use_vref = device_property_read_bool(dev, "vref-supply");
	pdata->vref_buffered =
		device_property_read_bool(dev, "microchip,vref-buffered");

	return 0;
}

static int mcp4725_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct mcp4725_data *data;
	struct iio_dev *indio_dev;
	struct mcp4725_platform_data *pdata, pdata_dt;
	u8 inbuf[4];
	u8 pd;
	u8 ref;
	int err;

	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
	if (indio_dev == NULL)
		return -ENOMEM;
	data = iio_priv(indio_dev);
	i2c_set_clientdata(client, indio_dev);
	data->client = client;
	if (dev_fwnode(&client->dev))
		data->id = (uintptr_t)device_get_match_data(&client->dev);
	else
		data->id = id->driver_data;
	pdata = dev_get_platdata(&client->dev);

	if (!pdata) {
		err = mcp4725_probe_dt(&client->dev, &pdata_dt);
		if (err) {
			dev_err(&client->dev,
				"invalid platform or devicetree data");
			return err;
		}
		pdata = &pdata_dt;
	}

	if (data->id == MCP4725 && pdata->use_vref) {
		dev_err(&client->dev,
			"external reference is unavailable on MCP4725");
		return -EINVAL;
	}

	if (!pdata->use_vref && pdata->vref_buffered) {
		dev_err(&client->dev,
			"buffering is unavailable on the internal reference");
		return -EINVAL;
	}

	if (!pdata->use_vref)
		data->ref_mode = MCP472X_REF_VDD;
	else
		data->ref_mode = pdata->vref_buffered ?
			MCP472X_REF_VREF_BUFFERED :
			MCP472X_REF_VREF_UNBUFFERED;

	data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
	if (IS_ERR(data->vdd_reg))
		return PTR_ERR(data->vdd_reg);

	err = regulator_enable(data->vdd_reg);
	if (err)
		return err;

	if (pdata->use_vref) {
		data->vref_reg = devm_regulator_get(&client->dev, "vref");
		if (IS_ERR(data->vref_reg)) {
			err = PTR_ERR(data->vref_reg);
			goto err_disable_vdd_reg;
		}

		err = regulator_enable(data->vref_reg);
		if (err)
			goto err_disable_vdd_reg;
	}

	indio_dev->name = id->name;
	indio_dev->info = &mcp4725_info;
	indio_dev->channels = &mcp472x_channel[id->driver_data];
	indio_dev->num_channels = 1;
	indio_dev->modes = INDIO_DIRECT_MODE;

	/* read current DAC value and settings */
	err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4);

	if (err < 0) {
		dev_err(&client->dev, "failed to read DAC value");
		goto err_disable_vref_reg;
	}
	pd = (inbuf[0] >> 1) & 0x3;
	data->powerdown = pd > 0;
	data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
	data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
	if (data->id == MCP4726)
		ref = (inbuf[3] >> 3) & 0x3;

	if (data->id == MCP4726 && ref != data->ref_mode) {
		dev_info(&client->dev,
			"voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
			data->ref_mode, ref, data->ref_mode);
		err = mcp4726_set_cfg(indio_dev);
		if (err < 0)
			goto err_disable_vref_reg;
	}
 
	err = iio_device_register(indio_dev);
	if (err)
		goto err_disable_vref_reg;

	return 0;

err_disable_vref_reg:
	if (data->vref_reg)
		regulator_disable(data->vref_reg);

err_disable_vdd_reg:
	regulator_disable(data->vdd_reg);

	return err;
}

static int mcp4725_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct mcp4725_data *data = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);

	if (data->vref_reg)
		regulator_disable(data->vref_reg);
	regulator_disable(data->vdd_reg);

	return 0;
}

static const struct i2c_device_id mcp4725_id[] = {
	{ "mcp4725", MCP4725 },
	{ "mcp4726", MCP4726 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, mcp4725_id);

static const struct of_device_id mcp4725_of_match[] = {
	{
		.compatible = "microchip,mcp4725",
		.data = (void *)MCP4725
	},
	{
		.compatible = "microchip,mcp4726",
		.data = (void *)MCP4726
	},
	{ }
};
MODULE_DEVICE_TABLE(of, mcp4725_of_match);

static struct i2c_driver mcp4725_driver = {
	.driver = {
		.name	= MCP4725_DRV_NAME,
		.of_match_table = mcp4725_of_match,
		.pm	= pm_sleep_ptr(&mcp4725_pm_ops),
	},
	.probe		= mcp4725_probe,
	.remove		= mcp4725_remove,
	.id_table	= mcp4725_id,
};
module_i2c_driver(mcp4725_driver);

MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
MODULE_LICENSE("GPL");