summaryrefslogtreecommitdiff
path: root/drivers/iio/dac/ad5755.c
blob: ee1e95a3a0c31b65c91104340fed80ca97bb5b55 (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
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
/*
 * AD5755, AD5755-1, AD5757, AD5735, AD5737 Digital to analog converters driver
 *
 * Copyright 2012 Analog Devices Inc.
 *
 * Licensed under the GPL-2.
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/platform_data/ad5755.h>

#define AD5755_NUM_CHANNELS 4

#define AD5755_ADDR(x)			((x) << 16)

#define AD5755_WRITE_REG_DATA(chan)	(chan)
#define AD5755_WRITE_REG_GAIN(chan)	(0x08 | (chan))
#define AD5755_WRITE_REG_OFFSET(chan)	(0x10 | (chan))
#define AD5755_WRITE_REG_CTRL(chan)	(0x1c | (chan))

#define AD5755_READ_REG_DATA(chan)	(chan)
#define AD5755_READ_REG_CTRL(chan)	(0x4 | (chan))
#define AD5755_READ_REG_GAIN(chan)	(0x8 | (chan))
#define AD5755_READ_REG_OFFSET(chan)	(0xc | (chan))
#define AD5755_READ_REG_CLEAR(chan)	(0x10 | (chan))
#define AD5755_READ_REG_SLEW(chan)	(0x14 | (chan))
#define AD5755_READ_REG_STATUS		0x18
#define AD5755_READ_REG_MAIN		0x19
#define AD5755_READ_REG_DC_DC		0x1a

#define AD5755_CTRL_REG_SLEW	0x0
#define AD5755_CTRL_REG_MAIN	0x1
#define AD5755_CTRL_REG_DAC	0x2
#define AD5755_CTRL_REG_DC_DC	0x3
#define AD5755_CTRL_REG_SW	0x4

#define AD5755_READ_FLAG 0x800000

#define AD5755_NOOP 0x1CE000

#define AD5755_DAC_INT_EN			BIT(8)
#define AD5755_DAC_CLR_EN			BIT(7)
#define AD5755_DAC_OUT_EN			BIT(6)
#define AD5755_DAC_INT_CURRENT_SENSE_RESISTOR	BIT(5)
#define AD5755_DAC_DC_DC_EN			BIT(4)
#define AD5755_DAC_VOLTAGE_OVERRANGE_EN		BIT(3)

#define AD5755_DC_DC_MAXV			0
#define AD5755_DC_DC_FREQ_SHIFT			2
#define AD5755_DC_DC_PHASE_SHIFT		4
#define AD5755_EXT_DC_DC_COMP_RES		BIT(6)

#define AD5755_SLEW_STEP_SIZE_SHIFT		0
#define AD5755_SLEW_RATE_SHIFT			3
#define AD5755_SLEW_ENABLE			BIT(12)

/**
 * struct ad5755_chip_info - chip specific information
 * @channel_template:	channel specification
 * @calib_shift:	shift for the calibration data registers
 * @has_voltage_out:	whether the chip has voltage outputs
 */
struct ad5755_chip_info {
	const struct iio_chan_spec channel_template;
	unsigned int calib_shift;
	bool has_voltage_out;
};

/**
 * struct ad5755_state - driver instance specific data
 * @spi:	spi device the driver is attached to
 * @chip_info:	chip model specific constants, available modes etc
 * @pwr_down:	bitmask which contains  hether a channel is powered down or not
 * @ctrl:	software shadow of the channel ctrl registers
 * @channels:	iio channel spec for the device
 * @data:	spi transfer buffers
 */
struct ad5755_state {
	struct spi_device		*spi;
	const struct ad5755_chip_info	*chip_info;
	unsigned int			pwr_down;
	unsigned int			ctrl[AD5755_NUM_CHANNELS];
	struct iio_chan_spec		channels[AD5755_NUM_CHANNELS];

	/*
	 * DMA (thus cache coherency maintenance) requires the
	 * transfer buffers to live in their own cache lines.
	 */

	union {
		u32 d32;
		u8 d8[4];
	} data[2] ____cacheline_aligned;
};

enum ad5755_type {
	ID_AD5755,
	ID_AD5757,
	ID_AD5735,
	ID_AD5737,
};

static int ad5755_write_unlocked(struct iio_dev *indio_dev,
	unsigned int reg, unsigned int val)
{
	struct ad5755_state *st = iio_priv(indio_dev);

	st->data[0].d32 = cpu_to_be32((reg << 16) | val);

	return spi_write(st->spi, &st->data[0].d8[1], 3);
}

static int ad5755_write_ctrl_unlocked(struct iio_dev *indio_dev,
	unsigned int channel, unsigned int reg, unsigned int val)
{
	return ad5755_write_unlocked(indio_dev,
		AD5755_WRITE_REG_CTRL(channel), (reg << 13) | val);
}

static int ad5755_write(struct iio_dev *indio_dev, unsigned int reg,
	unsigned int val)
{
	int ret;

	mutex_lock(&indio_dev->mlock);
	ret = ad5755_write_unlocked(indio_dev, reg, val);
	mutex_unlock(&indio_dev->mlock);

	return ret;
}

static int ad5755_write_ctrl(struct iio_dev *indio_dev, unsigned int channel,
	unsigned int reg, unsigned int val)
{
	int ret;

	mutex_lock(&indio_dev->mlock);
	ret = ad5755_write_ctrl_unlocked(indio_dev, channel, reg, val);
	mutex_unlock(&indio_dev->mlock);

	return ret;
}

static int ad5755_read(struct iio_dev *indio_dev, unsigned int addr)
{
	struct ad5755_state *st = iio_priv(indio_dev);
	int ret;
	struct spi_transfer t[] = {
		{
			.tx_buf = &st->data[0].d8[1],
			.len = 3,
			.cs_change = 1,
		}, {
			.tx_buf = &st->data[1].d8[1],
			.rx_buf = &st->data[1].d8[1],
			.len = 3,
		},
	};

	mutex_lock(&indio_dev->mlock);

	st->data[0].d32 = cpu_to_be32(AD5755_READ_FLAG | (addr << 16));
	st->data[1].d32 = cpu_to_be32(AD5755_NOOP);

	ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
	if (ret >= 0)
		ret = be32_to_cpu(st->data[1].d32) & 0xffff;

	mutex_unlock(&indio_dev->mlock);

	return ret;
}

static int ad5755_update_dac_ctrl(struct iio_dev *indio_dev,
	unsigned int channel, unsigned int set, unsigned int clr)
{
	struct ad5755_state *st = iio_priv(indio_dev);
	int ret;

	st->ctrl[channel] |= set;
	st->ctrl[channel] &= ~clr;

	ret = ad5755_write_ctrl_unlocked(indio_dev, channel,
		AD5755_CTRL_REG_DAC, st->ctrl[channel]);

	return ret;
}

static int ad5755_set_channel_pwr_down(struct iio_dev *indio_dev,
	unsigned int channel, bool pwr_down)
{
	struct ad5755_state *st = iio_priv(indio_dev);
	unsigned int mask = BIT(channel);

	mutex_lock(&indio_dev->mlock);

	if ((bool)(st->pwr_down & mask) == pwr_down)
		goto out_unlock;

	if (!pwr_down) {
		st->pwr_down &= ~mask;
		ad5755_update_dac_ctrl(indio_dev, channel,
			AD5755_DAC_INT_EN | AD5755_DAC_DC_DC_EN, 0);
		udelay(200);
		ad5755_update_dac_ctrl(indio_dev, channel,
			AD5755_DAC_OUT_EN, 0);
	} else {
		st->pwr_down |= mask;
		ad5755_update_dac_ctrl(indio_dev, channel,
			0, AD5755_DAC_INT_EN | AD5755_DAC_OUT_EN |
				AD5755_DAC_DC_DC_EN);
	}

out_unlock:
	mutex_unlock(&indio_dev->mlock);

	return 0;
}

static const int ad5755_min_max_table[][2] = {
	[AD5755_MODE_VOLTAGE_0V_5V] = { 0, 5000 },
	[AD5755_MODE_VOLTAGE_0V_10V] = { 0, 10000 },
	[AD5755_MODE_VOLTAGE_PLUSMINUS_5V] = { -5000, 5000 },
	[AD5755_MODE_VOLTAGE_PLUSMINUS_10V] = { -10000, 10000 },
	[AD5755_MODE_CURRENT_4mA_20mA] = { 4, 20 },
	[AD5755_MODE_CURRENT_0mA_20mA] = { 0, 20 },
	[AD5755_MODE_CURRENT_0mA_24mA] = { 0, 24 },
};

static void ad5755_get_min_max(struct ad5755_state *st,
	struct iio_chan_spec const *chan, int *min, int *max)
{
	enum ad5755_mode mode = st->ctrl[chan->channel] & 7;
	*min = ad5755_min_max_table[mode][0];
	*max = ad5755_min_max_table[mode][1];
}

static inline int ad5755_get_offset(struct ad5755_state *st,
	struct iio_chan_spec const *chan)
{
	int min, max;

	ad5755_get_min_max(st, chan, &min, &max);
	return (min * (1 << chan->scan_type.realbits)) / (max - min);
}

static int ad5755_chan_reg_info(struct ad5755_state *st,
	struct iio_chan_spec const *chan, long info, bool write,
	unsigned int *reg, unsigned int *shift, unsigned int *offset)
{
	switch (info) {
	case IIO_CHAN_INFO_RAW:
		if (write)
			*reg = AD5755_WRITE_REG_DATA(chan->address);
		else
			*reg = AD5755_READ_REG_DATA(chan->address);
		*shift = chan->scan_type.shift;
		*offset = 0;
		break;
	case IIO_CHAN_INFO_CALIBBIAS:
		if (write)
			*reg = AD5755_WRITE_REG_OFFSET(chan->address);
		else
			*reg = AD5755_READ_REG_OFFSET(chan->address);
		*shift = st->chip_info->calib_shift;
		*offset = 32768;
		break;
	case IIO_CHAN_INFO_CALIBSCALE:
		if (write)
			*reg =  AD5755_WRITE_REG_GAIN(chan->address);
		else
			*reg =  AD5755_READ_REG_GAIN(chan->address);
		*shift = st->chip_info->calib_shift;
		*offset = 0;
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static int ad5755_read_raw(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan, int *val, int *val2, long info)
{
	struct ad5755_state *st = iio_priv(indio_dev);
	unsigned int reg, shift, offset;
	int min, max;
	int ret;

	switch (info) {
	case IIO_CHAN_INFO_SCALE:
		ad5755_get_min_max(st, chan, &min, &max);
		*val = max - min;
		*val2 = chan->scan_type.realbits;
		return IIO_VAL_FRACTIONAL_LOG2;
	case IIO_CHAN_INFO_OFFSET:
		*val = ad5755_get_offset(st, chan);
		return IIO_VAL_INT;
	default:
		ret = ad5755_chan_reg_info(st, chan, info, false,
						&reg, &shift, &offset);
		if (ret)
			return ret;

		ret = ad5755_read(indio_dev, reg);
		if (ret < 0)
			return ret;

		*val = (ret - offset) >> shift;

		return IIO_VAL_INT;
	}

	return -EINVAL;
}

static int ad5755_write_raw(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan, int val, int val2, long info)
{
	struct ad5755_state *st = iio_priv(indio_dev);
	unsigned int shift, reg, offset;
	int ret;

	ret = ad5755_chan_reg_info(st, chan, info, true,
					&reg, &shift, &offset);
	if (ret)
		return ret;

	val <<= shift;
	val += offset;

	if (val < 0 || val > 0xffff)
		return -EINVAL;

	return ad5755_write(indio_dev, reg, val);
}

static ssize_t ad5755_read_powerdown(struct iio_dev *indio_dev, uintptr_t priv,
	const struct iio_chan_spec *chan, char *buf)
{
	struct ad5755_state *st = iio_priv(indio_dev);

	return sprintf(buf, "%d\n",
		       (bool)(st->pwr_down & (1 << chan->channel)));
}

static ssize_t ad5755_write_powerdown(struct iio_dev *indio_dev, uintptr_t priv,
	struct iio_chan_spec const *chan, const char *buf, size_t len)
{
	bool pwr_down;
	int ret;

	ret = strtobool(buf, &pwr_down);
	if (ret)
		return ret;

	ret = ad5755_set_channel_pwr_down(indio_dev, chan->channel, pwr_down);
	return ret ? ret : len;
}

static const struct iio_info ad5755_info = {
	.read_raw = ad5755_read_raw,
	.write_raw = ad5755_write_raw,
	.driver_module = THIS_MODULE,
};

static const struct iio_chan_spec_ext_info ad5755_ext_info[] = {
	{
		.name = "powerdown",
		.read = ad5755_read_powerdown,
		.write = ad5755_write_powerdown,
		.shared = IIO_SEPARATE,
	},
	{ },
};

#define AD5755_CHANNEL(_bits) {					\
	.indexed = 1,						\
	.output = 1,						\
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
		BIT(IIO_CHAN_INFO_SCALE) |			\
		BIT(IIO_CHAN_INFO_OFFSET) |			\
		BIT(IIO_CHAN_INFO_CALIBSCALE) |			\
		BIT(IIO_CHAN_INFO_CALIBBIAS),			\
	.scan_type = IIO_ST('u', (_bits), 16, 16 - (_bits)),	\
	.ext_info = ad5755_ext_info,				\
}

static const struct ad5755_chip_info ad5755_chip_info_tbl[] = {
	[ID_AD5735] = {
		.channel_template = AD5755_CHANNEL(14),
		.has_voltage_out = true,
		.calib_shift = 4,
	},
	[ID_AD5737] = {
		.channel_template = AD5755_CHANNEL(14),
		.has_voltage_out = false,
		.calib_shift = 4,
	},
	[ID_AD5755] = {
		.channel_template = AD5755_CHANNEL(16),
		.has_voltage_out = true,
		.calib_shift = 0,
	},
	[ID_AD5757] = {
		.channel_template = AD5755_CHANNEL(16),
		.has_voltage_out = false,
		.calib_shift = 0,
	},
};

static bool ad5755_is_valid_mode(struct ad5755_state *st, enum ad5755_mode mode)
{
	switch (mode) {
	case AD5755_MODE_VOLTAGE_0V_5V:
	case AD5755_MODE_VOLTAGE_0V_10V:
	case AD5755_MODE_VOLTAGE_PLUSMINUS_5V:
	case AD5755_MODE_VOLTAGE_PLUSMINUS_10V:
		return st->chip_info->has_voltage_out;
	case AD5755_MODE_CURRENT_4mA_20mA:
	case AD5755_MODE_CURRENT_0mA_20mA:
	case AD5755_MODE_CURRENT_0mA_24mA:
		return true;
	default:
		return false;
	}
}

static int ad5755_setup_pdata(struct iio_dev *indio_dev,
			      const struct ad5755_platform_data *pdata)
{
	struct ad5755_state *st = iio_priv(indio_dev);
	unsigned int val;
	unsigned int i;
	int ret;

	if (pdata->dc_dc_phase > AD5755_DC_DC_PHASE_90_DEGREE ||
		pdata->dc_dc_freq > AD5755_DC_DC_FREQ_650kHZ ||
		pdata->dc_dc_maxv > AD5755_DC_DC_MAXV_29V5)
		return -EINVAL;

	val = pdata->dc_dc_maxv << AD5755_DC_DC_MAXV;
	val |= pdata->dc_dc_freq << AD5755_DC_DC_FREQ_SHIFT;
	val |= pdata->dc_dc_phase << AD5755_DC_DC_PHASE_SHIFT;
	if (pdata->ext_dc_dc_compenstation_resistor)
		val |= AD5755_EXT_DC_DC_COMP_RES;

	ret = ad5755_write_ctrl(indio_dev, 0, AD5755_CTRL_REG_DC_DC, val);
	if (ret < 0)
		return ret;

	for (i = 0; i < ARRAY_SIZE(pdata->dac); ++i) {
		val = pdata->dac[i].slew.step_size <<
			AD5755_SLEW_STEP_SIZE_SHIFT;
		val |= pdata->dac[i].slew.rate <<
			AD5755_SLEW_RATE_SHIFT;
		if (pdata->dac[i].slew.enable)
			val |= AD5755_SLEW_ENABLE;

		ret = ad5755_write_ctrl(indio_dev, i,
					AD5755_CTRL_REG_SLEW, val);
		if (ret < 0)
			return ret;
	}

	for (i = 0; i < ARRAY_SIZE(pdata->dac); ++i) {
		if (!ad5755_is_valid_mode(st, pdata->dac[i].mode))
			return -EINVAL;

		val = 0;
		if (!pdata->dac[i].ext_current_sense_resistor)
			val |= AD5755_DAC_INT_CURRENT_SENSE_RESISTOR;
		if (pdata->dac[i].enable_voltage_overrange)
			val |= AD5755_DAC_VOLTAGE_OVERRANGE_EN;
		val |= pdata->dac[i].mode;

		ret = ad5755_update_dac_ctrl(indio_dev, i, val, 0);
		if (ret < 0)
			return ret;
	}

	return 0;
}

static bool ad5755_is_voltage_mode(enum ad5755_mode mode)
{
	switch (mode) {
	case AD5755_MODE_VOLTAGE_0V_5V:
	case AD5755_MODE_VOLTAGE_0V_10V:
	case AD5755_MODE_VOLTAGE_PLUSMINUS_5V:
	case AD5755_MODE_VOLTAGE_PLUSMINUS_10V:
		return true;
	default:
		return false;
	}
}

static int ad5755_init_channels(struct iio_dev *indio_dev,
				const struct ad5755_platform_data *pdata)
{
	struct ad5755_state *st = iio_priv(indio_dev);
	struct iio_chan_spec *channels = st->channels;
	unsigned int i;

	for (i = 0; i < AD5755_NUM_CHANNELS; ++i) {
		channels[i] = st->chip_info->channel_template;
		channels[i].channel = i;
		channels[i].address = i;
		if (pdata && ad5755_is_voltage_mode(pdata->dac[i].mode))
			channels[i].type = IIO_VOLTAGE;
		else
			channels[i].type = IIO_CURRENT;
	}

	indio_dev->channels = channels;

	return 0;
}

#define AD5755_DEFAULT_DAC_PDATA { \
		.mode = AD5755_MODE_CURRENT_4mA_20mA, \
		.ext_current_sense_resistor = true, \
		.enable_voltage_overrange = false, \
		.slew = { \
			.enable = false, \
			.rate = AD5755_SLEW_RATE_64k, \
			.step_size = AD5755_SLEW_STEP_SIZE_1, \
		}, \
	}

static const struct ad5755_platform_data ad5755_default_pdata = {
	.ext_dc_dc_compenstation_resistor = false,
	.dc_dc_phase = AD5755_DC_DC_PHASE_ALL_SAME_EDGE,
	.dc_dc_freq = AD5755_DC_DC_FREQ_410kHZ,
	.dc_dc_maxv = AD5755_DC_DC_MAXV_23V,
	.dac = {
		[0] = AD5755_DEFAULT_DAC_PDATA,
		[1] = AD5755_DEFAULT_DAC_PDATA,
		[2] = AD5755_DEFAULT_DAC_PDATA,
		[3] = AD5755_DEFAULT_DAC_PDATA,
	},
};

static int ad5755_probe(struct spi_device *spi)
{
	enum ad5755_type type = spi_get_device_id(spi)->driver_data;
	const struct ad5755_platform_data *pdata = dev_get_platdata(&spi->dev);
	struct iio_dev *indio_dev;
	struct ad5755_state *st;
	int ret;

	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
	if (indio_dev == NULL) {
		dev_err(&spi->dev, "Failed to allocate iio device\n");
		return  -ENOMEM;
	}

	st = iio_priv(indio_dev);
	spi_set_drvdata(spi, indio_dev);

	st->chip_info = &ad5755_chip_info_tbl[type];
	st->spi = spi;
	st->pwr_down = 0xf;

	indio_dev->dev.parent = &spi->dev;
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->info = &ad5755_info;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->num_channels = AD5755_NUM_CHANNELS;

	if (!pdata)
		pdata = &ad5755_default_pdata;

	ret = ad5755_init_channels(indio_dev, pdata);
	if (ret)
		return ret;

	ret = ad5755_setup_pdata(indio_dev, pdata);
	if (ret)
		return ret;

	return devm_iio_device_register(&spi->dev, indio_dev);
}

static const struct spi_device_id ad5755_id[] = {
	{ "ad5755", ID_AD5755 },
	{ "ad5755-1", ID_AD5755 },
	{ "ad5757", ID_AD5757 },
	{ "ad5735", ID_AD5735 },
	{ "ad5737", ID_AD5737 },
	{}
};
MODULE_DEVICE_TABLE(spi, ad5755_id);

static struct spi_driver ad5755_driver = {
	.driver = {
		.name = "ad5755",
		.owner = THIS_MODULE,
	},
	.probe = ad5755_probe,
	.id_table = ad5755_id,
};
module_spi_driver(ad5755_driver);

MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Devices AD5755/55-1/57/35/37 DAC");
MODULE_LICENSE("GPL v2");