xref: /openbmc/linux/drivers/iio/dac/ad5064.c (revision e1e0a9e6)
1 /*
2  * AD5024, AD5025, AD5044, AD5045, AD5064, AD5064-1, AD5065, AD5628, AD5629R,
3  * AD5648, AD5666, AD5668, AD5669R Digital to analog converters driver
4  *
5  * Copyright 2011 Analog Devices Inc.
6  *
7  * Licensed under the GPL-2.
8  */
9 
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/spi/spi.h>
15 #include <linux/i2c.h>
16 #include <linux/slab.h>
17 #include <linux/sysfs.h>
18 #include <linux/regulator/consumer.h>
19 #include <asm/unaligned.h>
20 
21 #include <linux/iio/iio.h>
22 #include <linux/iio/sysfs.h>
23 
24 #define AD5064_MAX_DAC_CHANNELS			8
25 #define AD5064_MAX_VREFS			4
26 
27 #define AD5064_ADDR(x)				((x) << 20)
28 #define AD5064_CMD(x)				((x) << 24)
29 
30 #define AD5064_ADDR_DAC(chan)			(chan)
31 #define AD5064_ADDR_ALL_DAC			0xF
32 
33 #define AD5064_CMD_WRITE_INPUT_N		0x0
34 #define AD5064_CMD_UPDATE_DAC_N			0x1
35 #define AD5064_CMD_WRITE_INPUT_N_UPDATE_ALL	0x2
36 #define AD5064_CMD_WRITE_INPUT_N_UPDATE_N	0x3
37 #define AD5064_CMD_POWERDOWN_DAC		0x4
38 #define AD5064_CMD_CLEAR			0x5
39 #define AD5064_CMD_LDAC_MASK			0x6
40 #define AD5064_CMD_RESET			0x7
41 #define AD5064_CMD_CONFIG			0x8
42 
43 #define AD5064_CONFIG_DAISY_CHAIN_ENABLE	BIT(1)
44 #define AD5064_CONFIG_INT_VREF_ENABLE		BIT(0)
45 
46 #define AD5064_LDAC_PWRDN_NONE			0x0
47 #define AD5064_LDAC_PWRDN_1K			0x1
48 #define AD5064_LDAC_PWRDN_100K			0x2
49 #define AD5064_LDAC_PWRDN_3STATE		0x3
50 
51 /**
52  * struct ad5064_chip_info - chip specific information
53  * @shared_vref:	whether the vref supply is shared between channels
54  * @internal_vref:	internal reference voltage. 0 if the chip has no internal
55  *			vref.
56  * @channel:		channel specification
57  * @num_channels:	number of channels
58  */
59 
60 struct ad5064_chip_info {
61 	bool shared_vref;
62 	unsigned long internal_vref;
63 	const struct iio_chan_spec *channels;
64 	unsigned int num_channels;
65 };
66 
67 struct ad5064_state;
68 
69 typedef int (*ad5064_write_func)(struct ad5064_state *st, unsigned int cmd,
70 		unsigned int addr, unsigned int val);
71 
72 /**
73  * struct ad5064_state - driver instance specific data
74  * @dev:		the device for this driver instance
75  * @chip_info:		chip model specific constants, available modes etc
76  * @vref_reg:		vref supply regulators
77  * @pwr_down:		whether channel is powered down
78  * @pwr_down_mode:	channel's current power down mode
79  * @dac_cache:		current DAC raw value (chip does not support readback)
80  * @use_internal_vref:	set to true if the internal reference voltage should be
81  *			used.
82  * @write:		register write callback
83  * @data:		i2c/spi transfer buffers
84  */
85 
86 struct ad5064_state {
87 	struct device			*dev;
88 	const struct ad5064_chip_info	*chip_info;
89 	struct regulator_bulk_data	vref_reg[AD5064_MAX_VREFS];
90 	bool				pwr_down[AD5064_MAX_DAC_CHANNELS];
91 	u8				pwr_down_mode[AD5064_MAX_DAC_CHANNELS];
92 	unsigned int			dac_cache[AD5064_MAX_DAC_CHANNELS];
93 	bool				use_internal_vref;
94 
95 	ad5064_write_func		write;
96 
97 	/*
98 	 * DMA (thus cache coherency maintenance) requires the
99 	 * transfer buffers to live in their own cache lines.
100 	 */
101 	union {
102 		u8 i2c[3];
103 		__be32 spi;
104 	} data ____cacheline_aligned;
105 };
106 
107 enum ad5064_type {
108 	ID_AD5024,
109 	ID_AD5025,
110 	ID_AD5044,
111 	ID_AD5045,
112 	ID_AD5064,
113 	ID_AD5064_1,
114 	ID_AD5065,
115 	ID_AD5628_1,
116 	ID_AD5628_2,
117 	ID_AD5648_1,
118 	ID_AD5648_2,
119 	ID_AD5666_1,
120 	ID_AD5666_2,
121 	ID_AD5668_1,
122 	ID_AD5668_2,
123 };
124 
125 static int ad5064_write(struct ad5064_state *st, unsigned int cmd,
126 	unsigned int addr, unsigned int val, unsigned int shift)
127 {
128 	val <<= shift;
129 
130 	return st->write(st, cmd, addr, val);
131 }
132 
133 static int ad5064_sync_powerdown_mode(struct ad5064_state *st,
134 	unsigned int channel)
135 {
136 	unsigned int val;
137 	int ret;
138 
139 	val = (0x1 << channel);
140 
141 	if (st->pwr_down[channel])
142 		val |= st->pwr_down_mode[channel] << 8;
143 
144 	ret = ad5064_write(st, AD5064_CMD_POWERDOWN_DAC, 0, val, 0);
145 
146 	return ret;
147 }
148 
149 static const char * const ad5064_powerdown_modes[] = {
150 	"1kohm_to_gnd",
151 	"100kohm_to_gnd",
152 	"three_state",
153 };
154 
155 static int ad5064_get_powerdown_mode(struct iio_dev *indio_dev,
156 	const struct iio_chan_spec *chan)
157 {
158 	struct ad5064_state *st = iio_priv(indio_dev);
159 
160 	return st->pwr_down_mode[chan->channel] - 1;
161 }
162 
163 static int ad5064_set_powerdown_mode(struct iio_dev *indio_dev,
164 	const struct iio_chan_spec *chan, unsigned int mode)
165 {
166 	struct ad5064_state *st = iio_priv(indio_dev);
167 	int ret;
168 
169 	mutex_lock(&indio_dev->mlock);
170 	st->pwr_down_mode[chan->channel] = mode + 1;
171 
172 	ret = ad5064_sync_powerdown_mode(st, chan->channel);
173 	mutex_unlock(&indio_dev->mlock);
174 
175 	return ret;
176 }
177 
178 static const struct iio_enum ad5064_powerdown_mode_enum = {
179 	.items = ad5064_powerdown_modes,
180 	.num_items = ARRAY_SIZE(ad5064_powerdown_modes),
181 	.get = ad5064_get_powerdown_mode,
182 	.set = ad5064_set_powerdown_mode,
183 };
184 
185 static ssize_t ad5064_read_dac_powerdown(struct iio_dev *indio_dev,
186 	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
187 {
188 	struct ad5064_state *st = iio_priv(indio_dev);
189 
190 	return sprintf(buf, "%d\n", st->pwr_down[chan->channel]);
191 }
192 
193 static ssize_t ad5064_write_dac_powerdown(struct iio_dev *indio_dev,
194 	 uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
195 	 size_t len)
196 {
197 	struct ad5064_state *st = iio_priv(indio_dev);
198 	bool pwr_down;
199 	int ret;
200 
201 	ret = strtobool(buf, &pwr_down);
202 	if (ret)
203 		return ret;
204 
205 	mutex_lock(&indio_dev->mlock);
206 	st->pwr_down[chan->channel] = pwr_down;
207 
208 	ret = ad5064_sync_powerdown_mode(st, chan->channel);
209 	mutex_unlock(&indio_dev->mlock);
210 	return ret ? ret : len;
211 }
212 
213 static int ad5064_get_vref(struct ad5064_state *st,
214 	struct iio_chan_spec const *chan)
215 {
216 	unsigned int i;
217 
218 	if (st->use_internal_vref)
219 		return st->chip_info->internal_vref;
220 
221 	i = st->chip_info->shared_vref ? 0 : chan->channel;
222 	return regulator_get_voltage(st->vref_reg[i].consumer);
223 }
224 
225 static int ad5064_read_raw(struct iio_dev *indio_dev,
226 			   struct iio_chan_spec const *chan,
227 			   int *val,
228 			   int *val2,
229 			   long m)
230 {
231 	struct ad5064_state *st = iio_priv(indio_dev);
232 	int scale_uv;
233 
234 	switch (m) {
235 	case IIO_CHAN_INFO_RAW:
236 		*val = st->dac_cache[chan->channel];
237 		return IIO_VAL_INT;
238 	case IIO_CHAN_INFO_SCALE:
239 		scale_uv = ad5064_get_vref(st, chan);
240 		if (scale_uv < 0)
241 			return scale_uv;
242 
243 		scale_uv = (scale_uv * 100) >> chan->scan_type.realbits;
244 		*val =  scale_uv / 100000;
245 		*val2 = (scale_uv % 100000) * 10;
246 		return IIO_VAL_INT_PLUS_MICRO;
247 	default:
248 		break;
249 	}
250 	return -EINVAL;
251 }
252 
253 static int ad5064_write_raw(struct iio_dev *indio_dev,
254 	struct iio_chan_spec const *chan, int val, int val2, long mask)
255 {
256 	struct ad5064_state *st = iio_priv(indio_dev);
257 	int ret;
258 
259 	switch (mask) {
260 	case IIO_CHAN_INFO_RAW:
261 		if (val > (1 << chan->scan_type.realbits) || val < 0)
262 			return -EINVAL;
263 
264 		mutex_lock(&indio_dev->mlock);
265 		ret = ad5064_write(st, AD5064_CMD_WRITE_INPUT_N_UPDATE_N,
266 				chan->address, val, chan->scan_type.shift);
267 		if (ret == 0)
268 			st->dac_cache[chan->channel] = val;
269 		mutex_unlock(&indio_dev->mlock);
270 		break;
271 	default:
272 		ret = -EINVAL;
273 	}
274 
275 	return ret;
276 }
277 
278 static const struct iio_info ad5064_info = {
279 	.read_raw = ad5064_read_raw,
280 	.write_raw = ad5064_write_raw,
281 	.driver_module = THIS_MODULE,
282 };
283 
284 static const struct iio_chan_spec_ext_info ad5064_ext_info[] = {
285 	{
286 		.name = "powerdown",
287 		.read = ad5064_read_dac_powerdown,
288 		.write = ad5064_write_dac_powerdown,
289 	},
290 	IIO_ENUM("powerdown_mode", false, &ad5064_powerdown_mode_enum),
291 	IIO_ENUM_AVAILABLE("powerdown_mode", &ad5064_powerdown_mode_enum),
292 	{ },
293 };
294 
295 #define AD5064_CHANNEL(chan, bits) {				\
296 	.type = IIO_VOLTAGE,					\
297 	.indexed = 1,						\
298 	.output = 1,						\
299 	.channel = (chan),					\
300 	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |		\
301 	IIO_CHAN_INFO_SCALE_SEPARATE_BIT,			\
302 	.address = AD5064_ADDR_DAC(chan),			\
303 	.scan_type = IIO_ST('u', (bits), 16, 20 - (bits)),	\
304 	.ext_info = ad5064_ext_info,				\
305 }
306 
307 #define DECLARE_AD5064_CHANNELS(name, bits) \
308 const struct iio_chan_spec name[] = { \
309 	AD5064_CHANNEL(0, bits), \
310 	AD5064_CHANNEL(1, bits), \
311 	AD5064_CHANNEL(2, bits), \
312 	AD5064_CHANNEL(3, bits), \
313 	AD5064_CHANNEL(4, bits), \
314 	AD5064_CHANNEL(5, bits), \
315 	AD5064_CHANNEL(6, bits), \
316 	AD5064_CHANNEL(7, bits), \
317 }
318 
319 static DECLARE_AD5064_CHANNELS(ad5024_channels, 12);
320 static DECLARE_AD5064_CHANNELS(ad5044_channels, 14);
321 static DECLARE_AD5064_CHANNELS(ad5064_channels, 16);
322 
323 static const struct ad5064_chip_info ad5064_chip_info_tbl[] = {
324 	[ID_AD5024] = {
325 		.shared_vref = false,
326 		.channels = ad5024_channels,
327 		.num_channels = 4,
328 	},
329 	[ID_AD5025] = {
330 		.shared_vref = false,
331 		.channels = ad5024_channels,
332 		.num_channels = 2,
333 	},
334 	[ID_AD5044] = {
335 		.shared_vref = false,
336 		.channels = ad5044_channels,
337 		.num_channels = 4,
338 	},
339 	[ID_AD5045] = {
340 		.shared_vref = false,
341 		.channels = ad5044_channels,
342 		.num_channels = 2,
343 	},
344 	[ID_AD5064] = {
345 		.shared_vref = false,
346 		.channels = ad5064_channels,
347 		.num_channels = 4,
348 	},
349 	[ID_AD5064_1] = {
350 		.shared_vref = true,
351 		.channels = ad5064_channels,
352 		.num_channels = 4,
353 	},
354 	[ID_AD5065] = {
355 		.shared_vref = false,
356 		.channels = ad5064_channels,
357 		.num_channels = 2,
358 	},
359 	[ID_AD5628_1] = {
360 		.shared_vref = true,
361 		.internal_vref = 2500000,
362 		.channels = ad5024_channels,
363 		.num_channels = 8,
364 	},
365 	[ID_AD5628_2] = {
366 		.shared_vref = true,
367 		.internal_vref = 5000000,
368 		.channels = ad5024_channels,
369 		.num_channels = 8,
370 	},
371 	[ID_AD5648_1] = {
372 		.shared_vref = true,
373 		.internal_vref = 2500000,
374 		.channels = ad5044_channels,
375 		.num_channels = 8,
376 	},
377 	[ID_AD5648_2] = {
378 		.shared_vref = true,
379 		.internal_vref = 5000000,
380 		.channels = ad5044_channels,
381 		.num_channels = 8,
382 	},
383 	[ID_AD5666_1] = {
384 		.shared_vref = true,
385 		.internal_vref = 2500000,
386 		.channels = ad5064_channels,
387 		.num_channels = 4,
388 	},
389 	[ID_AD5666_2] = {
390 		.shared_vref = true,
391 		.internal_vref = 5000000,
392 		.channels = ad5064_channels,
393 		.num_channels = 4,
394 	},
395 	[ID_AD5668_1] = {
396 		.shared_vref = true,
397 		.internal_vref = 2500000,
398 		.channels = ad5064_channels,
399 		.num_channels = 8,
400 	},
401 	[ID_AD5668_2] = {
402 		.shared_vref = true,
403 		.internal_vref = 5000000,
404 		.channels = ad5064_channels,
405 		.num_channels = 8,
406 	},
407 };
408 
409 static inline unsigned int ad5064_num_vref(struct ad5064_state *st)
410 {
411 	return st->chip_info->shared_vref ? 1 : st->chip_info->num_channels;
412 }
413 
414 static const char * const ad5064_vref_names[] = {
415 	"vrefA",
416 	"vrefB",
417 	"vrefC",
418 	"vrefD",
419 };
420 
421 static const char * const ad5064_vref_name(struct ad5064_state *st,
422 	unsigned int vref)
423 {
424 	return st->chip_info->shared_vref ? "vref" : ad5064_vref_names[vref];
425 }
426 
427 static int ad5064_probe(struct device *dev, enum ad5064_type type,
428 			const char *name, ad5064_write_func write)
429 {
430 	struct iio_dev *indio_dev;
431 	struct ad5064_state *st;
432 	unsigned int i;
433 	int ret;
434 
435 	indio_dev = iio_device_alloc(sizeof(*st));
436 	if (indio_dev == NULL)
437 		return  -ENOMEM;
438 
439 	st = iio_priv(indio_dev);
440 	dev_set_drvdata(dev, indio_dev);
441 
442 	st->chip_info = &ad5064_chip_info_tbl[type];
443 	st->dev = dev;
444 	st->write = write;
445 
446 	for (i = 0; i < ad5064_num_vref(st); ++i)
447 		st->vref_reg[i].supply = ad5064_vref_name(st, i);
448 
449 	ret = regulator_bulk_get(dev, ad5064_num_vref(st),
450 		st->vref_reg);
451 	if (ret) {
452 		if (!st->chip_info->internal_vref)
453 			goto error_free;
454 		st->use_internal_vref = true;
455 		ret = ad5064_write(st, AD5064_CMD_CONFIG, 0,
456 			AD5064_CONFIG_INT_VREF_ENABLE, 0);
457 		if (ret) {
458 			dev_err(dev, "Failed to enable internal vref: %d\n",
459 				ret);
460 			goto error_free;
461 		}
462 	} else {
463 		ret = regulator_bulk_enable(ad5064_num_vref(st), st->vref_reg);
464 		if (ret)
465 			goto error_free_reg;
466 	}
467 
468 	for (i = 0; i < st->chip_info->num_channels; ++i) {
469 		st->pwr_down_mode[i] = AD5064_LDAC_PWRDN_1K;
470 		st->dac_cache[i] = 0x8000;
471 	}
472 
473 	indio_dev->dev.parent = dev;
474 	indio_dev->name = name;
475 	indio_dev->info = &ad5064_info;
476 	indio_dev->modes = INDIO_DIRECT_MODE;
477 	indio_dev->channels = st->chip_info->channels;
478 	indio_dev->num_channels = st->chip_info->num_channels;
479 
480 	ret = iio_device_register(indio_dev);
481 	if (ret)
482 		goto error_disable_reg;
483 
484 	return 0;
485 
486 error_disable_reg:
487 	if (!st->use_internal_vref)
488 		regulator_bulk_disable(ad5064_num_vref(st), st->vref_reg);
489 error_free_reg:
490 	if (!st->use_internal_vref)
491 		regulator_bulk_free(ad5064_num_vref(st), st->vref_reg);
492 error_free:
493 	iio_device_free(indio_dev);
494 
495 	return ret;
496 }
497 
498 static int ad5064_remove(struct device *dev)
499 {
500 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
501 	struct ad5064_state *st = iio_priv(indio_dev);
502 
503 	iio_device_unregister(indio_dev);
504 
505 	if (!st->use_internal_vref) {
506 		regulator_bulk_disable(ad5064_num_vref(st), st->vref_reg);
507 		regulator_bulk_free(ad5064_num_vref(st), st->vref_reg);
508 	}
509 
510 	iio_device_free(indio_dev);
511 
512 	return 0;
513 }
514 
515 #if IS_ENABLED(CONFIG_SPI_MASTER)
516 
517 static int ad5064_spi_write(struct ad5064_state *st, unsigned int cmd,
518 	unsigned int addr, unsigned int val)
519 {
520 	struct spi_device *spi = to_spi_device(st->dev);
521 
522 	st->data.spi = cpu_to_be32(AD5064_CMD(cmd) | AD5064_ADDR(addr) | val);
523 	return spi_write(spi, &st->data.spi, sizeof(st->data.spi));
524 }
525 
526 static int ad5064_spi_probe(struct spi_device *spi)
527 {
528 	const struct spi_device_id *id = spi_get_device_id(spi);
529 
530 	return ad5064_probe(&spi->dev, id->driver_data, id->name,
531 				ad5064_spi_write);
532 }
533 
534 static int ad5064_spi_remove(struct spi_device *spi)
535 {
536 	return ad5064_remove(&spi->dev);
537 }
538 
539 static const struct spi_device_id ad5064_spi_ids[] = {
540 	{"ad5024", ID_AD5024},
541 	{"ad5025", ID_AD5025},
542 	{"ad5044", ID_AD5044},
543 	{"ad5045", ID_AD5045},
544 	{"ad5064", ID_AD5064},
545 	{"ad5064-1", ID_AD5064_1},
546 	{"ad5065", ID_AD5065},
547 	{"ad5628-1", ID_AD5628_1},
548 	{"ad5628-2", ID_AD5628_2},
549 	{"ad5648-1", ID_AD5648_1},
550 	{"ad5648-2", ID_AD5648_2},
551 	{"ad5666-1", ID_AD5666_1},
552 	{"ad5666-2", ID_AD5666_2},
553 	{"ad5668-1", ID_AD5668_1},
554 	{"ad5668-2", ID_AD5668_2},
555 	{"ad5668-3", ID_AD5668_2}, /* similar enough to ad5668-2 */
556 	{}
557 };
558 MODULE_DEVICE_TABLE(spi, ad5064_spi_ids);
559 
560 static struct spi_driver ad5064_spi_driver = {
561 	.driver = {
562 		   .name = "ad5064",
563 		   .owner = THIS_MODULE,
564 	},
565 	.probe = ad5064_spi_probe,
566 	.remove = ad5064_spi_remove,
567 	.id_table = ad5064_spi_ids,
568 };
569 
570 static int __init ad5064_spi_register_driver(void)
571 {
572 	return spi_register_driver(&ad5064_spi_driver);
573 }
574 
575 static void ad5064_spi_unregister_driver(void)
576 {
577 	spi_unregister_driver(&ad5064_spi_driver);
578 }
579 
580 #else
581 
582 static inline int ad5064_spi_register_driver(void) { return 0; }
583 static inline void ad5064_spi_unregister_driver(void) { }
584 
585 #endif
586 
587 #if IS_ENABLED(CONFIG_I2C)
588 
589 static int ad5064_i2c_write(struct ad5064_state *st, unsigned int cmd,
590 	unsigned int addr, unsigned int val)
591 {
592 	struct i2c_client *i2c = to_i2c_client(st->dev);
593 
594 	st->data.i2c[0] = (cmd << 4) | addr;
595 	put_unaligned_be16(val, &st->data.i2c[1]);
596 	return i2c_master_send(i2c, st->data.i2c, 3);
597 }
598 
599 static int ad5064_i2c_probe(struct i2c_client *i2c,
600 	const struct i2c_device_id *id)
601 {
602 	return ad5064_probe(&i2c->dev, id->driver_data, id->name,
603 						ad5064_i2c_write);
604 }
605 
606 static int ad5064_i2c_remove(struct i2c_client *i2c)
607 {
608 	return ad5064_remove(&i2c->dev);
609 }
610 
611 static const struct i2c_device_id ad5064_i2c_ids[] = {
612 	{"ad5629-1", ID_AD5628_1},
613 	{"ad5629-2", ID_AD5628_2},
614 	{"ad5629-3", ID_AD5628_2}, /* similar enough to ad5629-2 */
615 	{"ad5669-1", ID_AD5668_1},
616 	{"ad5669-2", ID_AD5668_2},
617 	{"ad5669-3", ID_AD5668_2}, /* similar enough to ad5669-2 */
618 	{}
619 };
620 MODULE_DEVICE_TABLE(i2c, ad5064_i2c_ids);
621 
622 static struct i2c_driver ad5064_i2c_driver = {
623 	.driver = {
624 		   .name = "ad5064",
625 		   .owner = THIS_MODULE,
626 	},
627 	.probe = ad5064_i2c_probe,
628 	.remove = ad5064_i2c_remove,
629 	.id_table = ad5064_i2c_ids,
630 };
631 
632 static int __init ad5064_i2c_register_driver(void)
633 {
634 	return i2c_add_driver(&ad5064_i2c_driver);
635 }
636 
637 static void __exit ad5064_i2c_unregister_driver(void)
638 {
639 	i2c_del_driver(&ad5064_i2c_driver);
640 }
641 
642 #else
643 
644 static inline int ad5064_i2c_register_driver(void) { return 0; }
645 static inline void ad5064_i2c_unregister_driver(void) { }
646 
647 #endif
648 
649 static int __init ad5064_init(void)
650 {
651 	int ret;
652 
653 	ret = ad5064_spi_register_driver();
654 	if (ret)
655 		return ret;
656 
657 	ret = ad5064_i2c_register_driver();
658 	if (ret) {
659 		ad5064_spi_unregister_driver();
660 		return ret;
661 	}
662 
663 	return 0;
664 }
665 module_init(ad5064_init);
666 
667 static void __exit ad5064_exit(void)
668 {
669 	ad5064_i2c_unregister_driver();
670 	ad5064_spi_unregister_driver();
671 }
672 module_exit(ad5064_exit);
673 
674 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
675 MODULE_DESCRIPTION("Analog Devices AD5024 and similar multi-channel DACs");
676 MODULE_LICENSE("GPL v2");
677