xref: /openbmc/linux/drivers/iio/dac/ad5755.c (revision 6c33a6f4)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * AD5755, AD5755-1, AD5757, AD5735, AD5737 Digital to analog converters driver
4  *
5  * Copyright 2012 Analog Devices Inc.
6  */
7 
8 #include <linux/device.h>
9 #include <linux/err.h>
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/spi/spi.h>
13 #include <linux/slab.h>
14 #include <linux/sysfs.h>
15 #include <linux/delay.h>
16 #include <linux/of.h>
17 #include <linux/iio/iio.h>
18 #include <linux/iio/sysfs.h>
19 #include <linux/platform_data/ad5755.h>
20 
21 #define AD5755_NUM_CHANNELS 4
22 
23 #define AD5755_ADDR(x)			((x) << 16)
24 
25 #define AD5755_WRITE_REG_DATA(chan)	(chan)
26 #define AD5755_WRITE_REG_GAIN(chan)	(0x08 | (chan))
27 #define AD5755_WRITE_REG_OFFSET(chan)	(0x10 | (chan))
28 #define AD5755_WRITE_REG_CTRL(chan)	(0x1c | (chan))
29 
30 #define AD5755_READ_REG_DATA(chan)	(chan)
31 #define AD5755_READ_REG_CTRL(chan)	(0x4 | (chan))
32 #define AD5755_READ_REG_GAIN(chan)	(0x8 | (chan))
33 #define AD5755_READ_REG_OFFSET(chan)	(0xc | (chan))
34 #define AD5755_READ_REG_CLEAR(chan)	(0x10 | (chan))
35 #define AD5755_READ_REG_SLEW(chan)	(0x14 | (chan))
36 #define AD5755_READ_REG_STATUS		0x18
37 #define AD5755_READ_REG_MAIN		0x19
38 #define AD5755_READ_REG_DC_DC		0x1a
39 
40 #define AD5755_CTRL_REG_SLEW	0x0
41 #define AD5755_CTRL_REG_MAIN	0x1
42 #define AD5755_CTRL_REG_DAC	0x2
43 #define AD5755_CTRL_REG_DC_DC	0x3
44 #define AD5755_CTRL_REG_SW	0x4
45 
46 #define AD5755_READ_FLAG 0x800000
47 
48 #define AD5755_NOOP 0x1CE000
49 
50 #define AD5755_DAC_INT_EN			BIT(8)
51 #define AD5755_DAC_CLR_EN			BIT(7)
52 #define AD5755_DAC_OUT_EN			BIT(6)
53 #define AD5755_DAC_INT_CURRENT_SENSE_RESISTOR	BIT(5)
54 #define AD5755_DAC_DC_DC_EN			BIT(4)
55 #define AD5755_DAC_VOLTAGE_OVERRANGE_EN		BIT(3)
56 
57 #define AD5755_DC_DC_MAXV			0
58 #define AD5755_DC_DC_FREQ_SHIFT			2
59 #define AD5755_DC_DC_PHASE_SHIFT		4
60 #define AD5755_EXT_DC_DC_COMP_RES		BIT(6)
61 
62 #define AD5755_SLEW_STEP_SIZE_SHIFT		0
63 #define AD5755_SLEW_RATE_SHIFT			3
64 #define AD5755_SLEW_ENABLE			BIT(12)
65 
66 /**
67  * struct ad5755_chip_info - chip specific information
68  * @channel_template:	channel specification
69  * @calib_shift:	shift for the calibration data registers
70  * @has_voltage_out:	whether the chip has voltage outputs
71  */
72 struct ad5755_chip_info {
73 	const struct iio_chan_spec channel_template;
74 	unsigned int calib_shift;
75 	bool has_voltage_out;
76 };
77 
78 /**
79  * struct ad5755_state - driver instance specific data
80  * @spi:	spi device the driver is attached to
81  * @chip_info:	chip model specific constants, available modes etc
82  * @pwr_down:	bitmask which contains  hether a channel is powered down or not
83  * @ctrl:	software shadow of the channel ctrl registers
84  * @channels:	iio channel spec for the device
85  * @data:	spi transfer buffers
86  */
87 struct ad5755_state {
88 	struct spi_device		*spi;
89 	const struct ad5755_chip_info	*chip_info;
90 	unsigned int			pwr_down;
91 	unsigned int			ctrl[AD5755_NUM_CHANNELS];
92 	struct iio_chan_spec		channels[AD5755_NUM_CHANNELS];
93 
94 	/*
95 	 * DMA (thus cache coherency maintenance) requires the
96 	 * transfer buffers to live in their own cache lines.
97 	 */
98 
99 	union {
100 		__be32 d32;
101 		u8 d8[4];
102 	} data[2] ____cacheline_aligned;
103 };
104 
105 enum ad5755_type {
106 	ID_AD5755,
107 	ID_AD5757,
108 	ID_AD5735,
109 	ID_AD5737,
110 };
111 
112 #ifdef CONFIG_OF
113 static const int ad5755_dcdc_freq_table[][2] = {
114 	{ 250000, AD5755_DC_DC_FREQ_250kHZ },
115 	{ 410000, AD5755_DC_DC_FREQ_410kHZ },
116 	{ 650000, AD5755_DC_DC_FREQ_650kHZ }
117 };
118 
119 static const int ad5755_dcdc_maxv_table[][2] = {
120 	{ 23000000, AD5755_DC_DC_MAXV_23V },
121 	{ 24500000, AD5755_DC_DC_MAXV_24V5 },
122 	{ 27000000, AD5755_DC_DC_MAXV_27V },
123 	{ 29500000, AD5755_DC_DC_MAXV_29V5 },
124 };
125 
126 static const int ad5755_slew_rate_table[][2] = {
127 	{ 64000, AD5755_SLEW_RATE_64k },
128 	{ 32000, AD5755_SLEW_RATE_32k },
129 	{ 16000, AD5755_SLEW_RATE_16k },
130 	{ 8000, AD5755_SLEW_RATE_8k },
131 	{ 4000, AD5755_SLEW_RATE_4k },
132 	{ 2000, AD5755_SLEW_RATE_2k },
133 	{ 1000, AD5755_SLEW_RATE_1k },
134 	{ 500, AD5755_SLEW_RATE_500 },
135 	{ 250, AD5755_SLEW_RATE_250 },
136 	{ 125, AD5755_SLEW_RATE_125 },
137 	{ 64, AD5755_SLEW_RATE_64 },
138 	{ 32, AD5755_SLEW_RATE_32 },
139 	{ 16, AD5755_SLEW_RATE_16 },
140 	{ 8, AD5755_SLEW_RATE_8 },
141 	{ 4, AD5755_SLEW_RATE_4 },
142 	{ 0, AD5755_SLEW_RATE_0_5 },
143 };
144 
145 static const int ad5755_slew_step_table[][2] = {
146 	{ 256, AD5755_SLEW_STEP_SIZE_256 },
147 	{ 128, AD5755_SLEW_STEP_SIZE_128 },
148 	{ 64, AD5755_SLEW_STEP_SIZE_64 },
149 	{ 32, AD5755_SLEW_STEP_SIZE_32 },
150 	{ 16, AD5755_SLEW_STEP_SIZE_16 },
151 	{ 4, AD5755_SLEW_STEP_SIZE_4 },
152 	{ 2, AD5755_SLEW_STEP_SIZE_2 },
153 	{ 1, AD5755_SLEW_STEP_SIZE_1 },
154 };
155 #endif
156 
157 static int ad5755_write_unlocked(struct iio_dev *indio_dev,
158 	unsigned int reg, unsigned int val)
159 {
160 	struct ad5755_state *st = iio_priv(indio_dev);
161 
162 	st->data[0].d32 = cpu_to_be32((reg << 16) | val);
163 
164 	return spi_write(st->spi, &st->data[0].d8[1], 3);
165 }
166 
167 static int ad5755_write_ctrl_unlocked(struct iio_dev *indio_dev,
168 	unsigned int channel, unsigned int reg, unsigned int val)
169 {
170 	return ad5755_write_unlocked(indio_dev,
171 		AD5755_WRITE_REG_CTRL(channel), (reg << 13) | val);
172 }
173 
174 static int ad5755_write(struct iio_dev *indio_dev, unsigned int reg,
175 	unsigned int val)
176 {
177 	int ret;
178 
179 	mutex_lock(&indio_dev->mlock);
180 	ret = ad5755_write_unlocked(indio_dev, reg, val);
181 	mutex_unlock(&indio_dev->mlock);
182 
183 	return ret;
184 }
185 
186 static int ad5755_write_ctrl(struct iio_dev *indio_dev, unsigned int channel,
187 	unsigned int reg, unsigned int val)
188 {
189 	int ret;
190 
191 	mutex_lock(&indio_dev->mlock);
192 	ret = ad5755_write_ctrl_unlocked(indio_dev, channel, reg, val);
193 	mutex_unlock(&indio_dev->mlock);
194 
195 	return ret;
196 }
197 
198 static int ad5755_read(struct iio_dev *indio_dev, unsigned int addr)
199 {
200 	struct ad5755_state *st = iio_priv(indio_dev);
201 	int ret;
202 	struct spi_transfer t[] = {
203 		{
204 			.tx_buf = &st->data[0].d8[1],
205 			.len = 3,
206 			.cs_change = 1,
207 		}, {
208 			.tx_buf = &st->data[1].d8[1],
209 			.rx_buf = &st->data[1].d8[1],
210 			.len = 3,
211 		},
212 	};
213 
214 	mutex_lock(&indio_dev->mlock);
215 
216 	st->data[0].d32 = cpu_to_be32(AD5755_READ_FLAG | (addr << 16));
217 	st->data[1].d32 = cpu_to_be32(AD5755_NOOP);
218 
219 	ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
220 	if (ret >= 0)
221 		ret = be32_to_cpu(st->data[1].d32) & 0xffff;
222 
223 	mutex_unlock(&indio_dev->mlock);
224 
225 	return ret;
226 }
227 
228 static int ad5755_update_dac_ctrl(struct iio_dev *indio_dev,
229 	unsigned int channel, unsigned int set, unsigned int clr)
230 {
231 	struct ad5755_state *st = iio_priv(indio_dev);
232 	int ret;
233 
234 	st->ctrl[channel] |= set;
235 	st->ctrl[channel] &= ~clr;
236 
237 	ret = ad5755_write_ctrl_unlocked(indio_dev, channel,
238 		AD5755_CTRL_REG_DAC, st->ctrl[channel]);
239 
240 	return ret;
241 }
242 
243 static int ad5755_set_channel_pwr_down(struct iio_dev *indio_dev,
244 	unsigned int channel, bool pwr_down)
245 {
246 	struct ad5755_state *st = iio_priv(indio_dev);
247 	unsigned int mask = BIT(channel);
248 
249 	mutex_lock(&indio_dev->mlock);
250 
251 	if ((bool)(st->pwr_down & mask) == pwr_down)
252 		goto out_unlock;
253 
254 	if (!pwr_down) {
255 		st->pwr_down &= ~mask;
256 		ad5755_update_dac_ctrl(indio_dev, channel,
257 			AD5755_DAC_INT_EN | AD5755_DAC_DC_DC_EN, 0);
258 		udelay(200);
259 		ad5755_update_dac_ctrl(indio_dev, channel,
260 			AD5755_DAC_OUT_EN, 0);
261 	} else {
262 		st->pwr_down |= mask;
263 		ad5755_update_dac_ctrl(indio_dev, channel,
264 			0, AD5755_DAC_INT_EN | AD5755_DAC_OUT_EN |
265 				AD5755_DAC_DC_DC_EN);
266 	}
267 
268 out_unlock:
269 	mutex_unlock(&indio_dev->mlock);
270 
271 	return 0;
272 }
273 
274 static const int ad5755_min_max_table[][2] = {
275 	[AD5755_MODE_VOLTAGE_0V_5V] = { 0, 5000 },
276 	[AD5755_MODE_VOLTAGE_0V_10V] = { 0, 10000 },
277 	[AD5755_MODE_VOLTAGE_PLUSMINUS_5V] = { -5000, 5000 },
278 	[AD5755_MODE_VOLTAGE_PLUSMINUS_10V] = { -10000, 10000 },
279 	[AD5755_MODE_CURRENT_4mA_20mA] = { 4, 20 },
280 	[AD5755_MODE_CURRENT_0mA_20mA] = { 0, 20 },
281 	[AD5755_MODE_CURRENT_0mA_24mA] = { 0, 24 },
282 };
283 
284 static void ad5755_get_min_max(struct ad5755_state *st,
285 	struct iio_chan_spec const *chan, int *min, int *max)
286 {
287 	enum ad5755_mode mode = st->ctrl[chan->channel] & 7;
288 	*min = ad5755_min_max_table[mode][0];
289 	*max = ad5755_min_max_table[mode][1];
290 }
291 
292 static inline int ad5755_get_offset(struct ad5755_state *st,
293 	struct iio_chan_spec const *chan)
294 {
295 	int min, max;
296 
297 	ad5755_get_min_max(st, chan, &min, &max);
298 	return (min * (1 << chan->scan_type.realbits)) / (max - min);
299 }
300 
301 static int ad5755_chan_reg_info(struct ad5755_state *st,
302 	struct iio_chan_spec const *chan, long info, bool write,
303 	unsigned int *reg, unsigned int *shift, unsigned int *offset)
304 {
305 	switch (info) {
306 	case IIO_CHAN_INFO_RAW:
307 		if (write)
308 			*reg = AD5755_WRITE_REG_DATA(chan->address);
309 		else
310 			*reg = AD5755_READ_REG_DATA(chan->address);
311 		*shift = chan->scan_type.shift;
312 		*offset = 0;
313 		break;
314 	case IIO_CHAN_INFO_CALIBBIAS:
315 		if (write)
316 			*reg = AD5755_WRITE_REG_OFFSET(chan->address);
317 		else
318 			*reg = AD5755_READ_REG_OFFSET(chan->address);
319 		*shift = st->chip_info->calib_shift;
320 		*offset = 32768;
321 		break;
322 	case IIO_CHAN_INFO_CALIBSCALE:
323 		if (write)
324 			*reg =  AD5755_WRITE_REG_GAIN(chan->address);
325 		else
326 			*reg =  AD5755_READ_REG_GAIN(chan->address);
327 		*shift = st->chip_info->calib_shift;
328 		*offset = 0;
329 		break;
330 	default:
331 		return -EINVAL;
332 	}
333 
334 	return 0;
335 }
336 
337 static int ad5755_read_raw(struct iio_dev *indio_dev,
338 	const struct iio_chan_spec *chan, int *val, int *val2, long info)
339 {
340 	struct ad5755_state *st = iio_priv(indio_dev);
341 	unsigned int reg, shift, offset;
342 	int min, max;
343 	int ret;
344 
345 	switch (info) {
346 	case IIO_CHAN_INFO_SCALE:
347 		ad5755_get_min_max(st, chan, &min, &max);
348 		*val = max - min;
349 		*val2 = chan->scan_type.realbits;
350 		return IIO_VAL_FRACTIONAL_LOG2;
351 	case IIO_CHAN_INFO_OFFSET:
352 		*val = ad5755_get_offset(st, chan);
353 		return IIO_VAL_INT;
354 	default:
355 		ret = ad5755_chan_reg_info(st, chan, info, false,
356 						&reg, &shift, &offset);
357 		if (ret)
358 			return ret;
359 
360 		ret = ad5755_read(indio_dev, reg);
361 		if (ret < 0)
362 			return ret;
363 
364 		*val = (ret - offset) >> shift;
365 
366 		return IIO_VAL_INT;
367 	}
368 
369 	return -EINVAL;
370 }
371 
372 static int ad5755_write_raw(struct iio_dev *indio_dev,
373 	const struct iio_chan_spec *chan, int val, int val2, long info)
374 {
375 	struct ad5755_state *st = iio_priv(indio_dev);
376 	unsigned int shift, reg, offset;
377 	int ret;
378 
379 	ret = ad5755_chan_reg_info(st, chan, info, true,
380 					&reg, &shift, &offset);
381 	if (ret)
382 		return ret;
383 
384 	val <<= shift;
385 	val += offset;
386 
387 	if (val < 0 || val > 0xffff)
388 		return -EINVAL;
389 
390 	return ad5755_write(indio_dev, reg, val);
391 }
392 
393 static ssize_t ad5755_read_powerdown(struct iio_dev *indio_dev, uintptr_t priv,
394 	const struct iio_chan_spec *chan, char *buf)
395 {
396 	struct ad5755_state *st = iio_priv(indio_dev);
397 
398 	return sprintf(buf, "%d\n",
399 		       (bool)(st->pwr_down & (1 << chan->channel)));
400 }
401 
402 static ssize_t ad5755_write_powerdown(struct iio_dev *indio_dev, uintptr_t priv,
403 	struct iio_chan_spec const *chan, const char *buf, size_t len)
404 {
405 	bool pwr_down;
406 	int ret;
407 
408 	ret = strtobool(buf, &pwr_down);
409 	if (ret)
410 		return ret;
411 
412 	ret = ad5755_set_channel_pwr_down(indio_dev, chan->channel, pwr_down);
413 	return ret ? ret : len;
414 }
415 
416 static const struct iio_info ad5755_info = {
417 	.read_raw = ad5755_read_raw,
418 	.write_raw = ad5755_write_raw,
419 };
420 
421 static const struct iio_chan_spec_ext_info ad5755_ext_info[] = {
422 	{
423 		.name = "powerdown",
424 		.read = ad5755_read_powerdown,
425 		.write = ad5755_write_powerdown,
426 		.shared = IIO_SEPARATE,
427 	},
428 	{ },
429 };
430 
431 #define AD5755_CHANNEL(_bits) {					\
432 	.indexed = 1,						\
433 	.output = 1,						\
434 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
435 		BIT(IIO_CHAN_INFO_SCALE) |			\
436 		BIT(IIO_CHAN_INFO_OFFSET) |			\
437 		BIT(IIO_CHAN_INFO_CALIBSCALE) |			\
438 		BIT(IIO_CHAN_INFO_CALIBBIAS),			\
439 	.scan_type = {						\
440 		.sign = 'u',					\
441 		.realbits = (_bits),				\
442 		.storagebits = 16,				\
443 		.shift = 16 - (_bits),				\
444 	},							\
445 	.ext_info = ad5755_ext_info,				\
446 }
447 
448 static const struct ad5755_chip_info ad5755_chip_info_tbl[] = {
449 	[ID_AD5735] = {
450 		.channel_template = AD5755_CHANNEL(14),
451 		.has_voltage_out = true,
452 		.calib_shift = 4,
453 	},
454 	[ID_AD5737] = {
455 		.channel_template = AD5755_CHANNEL(14),
456 		.has_voltage_out = false,
457 		.calib_shift = 4,
458 	},
459 	[ID_AD5755] = {
460 		.channel_template = AD5755_CHANNEL(16),
461 		.has_voltage_out = true,
462 		.calib_shift = 0,
463 	},
464 	[ID_AD5757] = {
465 		.channel_template = AD5755_CHANNEL(16),
466 		.has_voltage_out = false,
467 		.calib_shift = 0,
468 	},
469 };
470 
471 static bool ad5755_is_valid_mode(struct ad5755_state *st, enum ad5755_mode mode)
472 {
473 	switch (mode) {
474 	case AD5755_MODE_VOLTAGE_0V_5V:
475 	case AD5755_MODE_VOLTAGE_0V_10V:
476 	case AD5755_MODE_VOLTAGE_PLUSMINUS_5V:
477 	case AD5755_MODE_VOLTAGE_PLUSMINUS_10V:
478 		return st->chip_info->has_voltage_out;
479 	case AD5755_MODE_CURRENT_4mA_20mA:
480 	case AD5755_MODE_CURRENT_0mA_20mA:
481 	case AD5755_MODE_CURRENT_0mA_24mA:
482 		return true;
483 	default:
484 		return false;
485 	}
486 }
487 
488 static int ad5755_setup_pdata(struct iio_dev *indio_dev,
489 			      const struct ad5755_platform_data *pdata)
490 {
491 	struct ad5755_state *st = iio_priv(indio_dev);
492 	unsigned int val;
493 	unsigned int i;
494 	int ret;
495 
496 	if (pdata->dc_dc_phase > AD5755_DC_DC_PHASE_90_DEGREE ||
497 		pdata->dc_dc_freq > AD5755_DC_DC_FREQ_650kHZ ||
498 		pdata->dc_dc_maxv > AD5755_DC_DC_MAXV_29V5)
499 		return -EINVAL;
500 
501 	val = pdata->dc_dc_maxv << AD5755_DC_DC_MAXV;
502 	val |= pdata->dc_dc_freq << AD5755_DC_DC_FREQ_SHIFT;
503 	val |= pdata->dc_dc_phase << AD5755_DC_DC_PHASE_SHIFT;
504 	if (pdata->ext_dc_dc_compenstation_resistor)
505 		val |= AD5755_EXT_DC_DC_COMP_RES;
506 
507 	ret = ad5755_write_ctrl(indio_dev, 0, AD5755_CTRL_REG_DC_DC, val);
508 	if (ret < 0)
509 		return ret;
510 
511 	for (i = 0; i < ARRAY_SIZE(pdata->dac); ++i) {
512 		val = pdata->dac[i].slew.step_size <<
513 			AD5755_SLEW_STEP_SIZE_SHIFT;
514 		val |= pdata->dac[i].slew.rate <<
515 			AD5755_SLEW_RATE_SHIFT;
516 		if (pdata->dac[i].slew.enable)
517 			val |= AD5755_SLEW_ENABLE;
518 
519 		ret = ad5755_write_ctrl(indio_dev, i,
520 					AD5755_CTRL_REG_SLEW, val);
521 		if (ret < 0)
522 			return ret;
523 	}
524 
525 	for (i = 0; i < ARRAY_SIZE(pdata->dac); ++i) {
526 		if (!ad5755_is_valid_mode(st, pdata->dac[i].mode))
527 			return -EINVAL;
528 
529 		val = 0;
530 		if (!pdata->dac[i].ext_current_sense_resistor)
531 			val |= AD5755_DAC_INT_CURRENT_SENSE_RESISTOR;
532 		if (pdata->dac[i].enable_voltage_overrange)
533 			val |= AD5755_DAC_VOLTAGE_OVERRANGE_EN;
534 		val |= pdata->dac[i].mode;
535 
536 		ret = ad5755_update_dac_ctrl(indio_dev, i, val, 0);
537 		if (ret < 0)
538 			return ret;
539 	}
540 
541 	return 0;
542 }
543 
544 static bool ad5755_is_voltage_mode(enum ad5755_mode mode)
545 {
546 	switch (mode) {
547 	case AD5755_MODE_VOLTAGE_0V_5V:
548 	case AD5755_MODE_VOLTAGE_0V_10V:
549 	case AD5755_MODE_VOLTAGE_PLUSMINUS_5V:
550 	case AD5755_MODE_VOLTAGE_PLUSMINUS_10V:
551 		return true;
552 	default:
553 		return false;
554 	}
555 }
556 
557 static int ad5755_init_channels(struct iio_dev *indio_dev,
558 				const struct ad5755_platform_data *pdata)
559 {
560 	struct ad5755_state *st = iio_priv(indio_dev);
561 	struct iio_chan_spec *channels = st->channels;
562 	unsigned int i;
563 
564 	for (i = 0; i < AD5755_NUM_CHANNELS; ++i) {
565 		channels[i] = st->chip_info->channel_template;
566 		channels[i].channel = i;
567 		channels[i].address = i;
568 		if (pdata && ad5755_is_voltage_mode(pdata->dac[i].mode))
569 			channels[i].type = IIO_VOLTAGE;
570 		else
571 			channels[i].type = IIO_CURRENT;
572 	}
573 
574 	indio_dev->channels = channels;
575 
576 	return 0;
577 }
578 
579 #define AD5755_DEFAULT_DAC_PDATA { \
580 		.mode = AD5755_MODE_CURRENT_4mA_20mA, \
581 		.ext_current_sense_resistor = true, \
582 		.enable_voltage_overrange = false, \
583 		.slew = { \
584 			.enable = false, \
585 			.rate = AD5755_SLEW_RATE_64k, \
586 			.step_size = AD5755_SLEW_STEP_SIZE_1, \
587 		}, \
588 	}
589 
590 static const struct ad5755_platform_data ad5755_default_pdata = {
591 	.ext_dc_dc_compenstation_resistor = false,
592 	.dc_dc_phase = AD5755_DC_DC_PHASE_ALL_SAME_EDGE,
593 	.dc_dc_freq = AD5755_DC_DC_FREQ_410kHZ,
594 	.dc_dc_maxv = AD5755_DC_DC_MAXV_23V,
595 	.dac = {
596 		[0] = AD5755_DEFAULT_DAC_PDATA,
597 		[1] = AD5755_DEFAULT_DAC_PDATA,
598 		[2] = AD5755_DEFAULT_DAC_PDATA,
599 		[3] = AD5755_DEFAULT_DAC_PDATA,
600 	},
601 };
602 
603 #ifdef CONFIG_OF
604 static struct ad5755_platform_data *ad5755_parse_dt(struct device *dev)
605 {
606 	struct device_node *np = dev->of_node;
607 	struct device_node *pp;
608 	struct ad5755_platform_data *pdata;
609 	unsigned int tmp;
610 	unsigned int tmparray[3];
611 	int devnr, i;
612 
613 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
614 	if (!pdata)
615 		return NULL;
616 
617 	pdata->ext_dc_dc_compenstation_resistor =
618 	    of_property_read_bool(np, "adi,ext-dc-dc-compenstation-resistor");
619 
620 	if (!of_property_read_u32(np, "adi,dc-dc-phase", &tmp))
621 		pdata->dc_dc_phase = tmp;
622 	else
623 		pdata->dc_dc_phase = AD5755_DC_DC_PHASE_ALL_SAME_EDGE;
624 
625 	pdata->dc_dc_freq = AD5755_DC_DC_FREQ_410kHZ;
626 	if (!of_property_read_u32(np, "adi,dc-dc-freq-hz", &tmp)) {
627 		for (i = 0; i < ARRAY_SIZE(ad5755_dcdc_freq_table); i++) {
628 			if (tmp == ad5755_dcdc_freq_table[i][0]) {
629 				pdata->dc_dc_freq = ad5755_dcdc_freq_table[i][1];
630 				break;
631 			}
632 		}
633 
634 		if (i == ARRAY_SIZE(ad5755_dcdc_freq_table)) {
635 			dev_err(dev,
636 				"adi,dc-dc-freq out of range selecting 410kHz");
637 		}
638 	}
639 
640 	pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_23V;
641 	if (!of_property_read_u32(np, "adi,dc-dc-max-microvolt", &tmp)) {
642 		for (i = 0; i < ARRAY_SIZE(ad5755_dcdc_maxv_table); i++) {
643 			if (tmp == ad5755_dcdc_maxv_table[i][0]) {
644 				pdata->dc_dc_maxv = ad5755_dcdc_maxv_table[i][1];
645 				break;
646 			}
647 		}
648 		if (i == ARRAY_SIZE(ad5755_dcdc_maxv_table)) {
649 				dev_err(dev,
650 					"adi,dc-dc-maxv out of range selecting 23V");
651 		}
652 	}
653 
654 	devnr = 0;
655 	for_each_child_of_node(np, pp) {
656 		if (devnr >= AD5755_NUM_CHANNELS) {
657 			dev_err(dev,
658 				"There is to many channels defined in DT\n");
659 			goto error_out;
660 		}
661 
662 		if (!of_property_read_u32(pp, "adi,mode", &tmp))
663 			pdata->dac[devnr].mode = tmp;
664 		else
665 			pdata->dac[devnr].mode = AD5755_MODE_CURRENT_4mA_20mA;
666 
667 		pdata->dac[devnr].ext_current_sense_resistor =
668 		    of_property_read_bool(pp, "adi,ext-current-sense-resistor");
669 
670 		pdata->dac[devnr].enable_voltage_overrange =
671 		    of_property_read_bool(pp, "adi,enable-voltage-overrange");
672 
673 		if (!of_property_read_u32_array(pp, "adi,slew", tmparray, 3)) {
674 			pdata->dac[devnr].slew.enable = tmparray[0];
675 
676 			pdata->dac[devnr].slew.rate = AD5755_SLEW_RATE_64k;
677 			for (i = 0; i < ARRAY_SIZE(ad5755_slew_rate_table); i++) {
678 				if (tmparray[1] == ad5755_slew_rate_table[i][0]) {
679 					pdata->dac[devnr].slew.rate =
680 						ad5755_slew_rate_table[i][1];
681 					break;
682 				}
683 			}
684 			if (i == ARRAY_SIZE(ad5755_slew_rate_table)) {
685 				dev_err(dev,
686 					"channel %d slew rate out of range selecting 64kHz",
687 					devnr);
688 			}
689 
690 			pdata->dac[devnr].slew.step_size = AD5755_SLEW_STEP_SIZE_1;
691 			for (i = 0; i < ARRAY_SIZE(ad5755_slew_step_table); i++) {
692 				if (tmparray[2] == ad5755_slew_step_table[i][0]) {
693 					pdata->dac[devnr].slew.step_size =
694 						ad5755_slew_step_table[i][1];
695 					break;
696 				}
697 			}
698 			if (i == ARRAY_SIZE(ad5755_slew_step_table)) {
699 				dev_err(dev,
700 					"channel %d slew step size out of range selecting 1 LSB",
701 					devnr);
702 			}
703 		} else {
704 			pdata->dac[devnr].slew.enable = false;
705 			pdata->dac[devnr].slew.rate = AD5755_SLEW_RATE_64k;
706 			pdata->dac[devnr].slew.step_size =
707 			    AD5755_SLEW_STEP_SIZE_1;
708 		}
709 		devnr++;
710 	}
711 
712 	return pdata;
713 
714  error_out:
715 	devm_kfree(dev, pdata);
716 	return NULL;
717 }
718 #else
719 static
720 struct ad5755_platform_data *ad5755_parse_dt(struct device *dev)
721 {
722 	return NULL;
723 }
724 #endif
725 
726 static int ad5755_probe(struct spi_device *spi)
727 {
728 	enum ad5755_type type = spi_get_device_id(spi)->driver_data;
729 	const struct ad5755_platform_data *pdata = dev_get_platdata(&spi->dev);
730 	struct iio_dev *indio_dev;
731 	struct ad5755_state *st;
732 	int ret;
733 
734 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
735 	if (indio_dev == NULL) {
736 		dev_err(&spi->dev, "Failed to allocate iio device\n");
737 		return  -ENOMEM;
738 	}
739 
740 	st = iio_priv(indio_dev);
741 	spi_set_drvdata(spi, indio_dev);
742 
743 	st->chip_info = &ad5755_chip_info_tbl[type];
744 	st->spi = spi;
745 	st->pwr_down = 0xf;
746 
747 	indio_dev->dev.parent = &spi->dev;
748 	indio_dev->name = spi_get_device_id(spi)->name;
749 	indio_dev->info = &ad5755_info;
750 	indio_dev->modes = INDIO_DIRECT_MODE;
751 	indio_dev->num_channels = AD5755_NUM_CHANNELS;
752 
753 	if (spi->dev.of_node)
754 		pdata = ad5755_parse_dt(&spi->dev);
755 	else
756 		pdata = spi->dev.platform_data;
757 
758 	if (!pdata) {
759 		dev_warn(&spi->dev, "no platform data? using default\n");
760 		pdata = &ad5755_default_pdata;
761 	}
762 
763 	ret = ad5755_init_channels(indio_dev, pdata);
764 	if (ret)
765 		return ret;
766 
767 	ret = ad5755_setup_pdata(indio_dev, pdata);
768 	if (ret)
769 		return ret;
770 
771 	return devm_iio_device_register(&spi->dev, indio_dev);
772 }
773 
774 static const struct spi_device_id ad5755_id[] = {
775 	{ "ad5755", ID_AD5755 },
776 	{ "ad5755-1", ID_AD5755 },
777 	{ "ad5757", ID_AD5757 },
778 	{ "ad5735", ID_AD5735 },
779 	{ "ad5737", ID_AD5737 },
780 	{}
781 };
782 MODULE_DEVICE_TABLE(spi, ad5755_id);
783 
784 static const struct of_device_id ad5755_of_match[] = {
785 	{ .compatible = "adi,ad5755" },
786 	{ .compatible = "adi,ad5755-1" },
787 	{ .compatible = "adi,ad5757" },
788 	{ .compatible = "adi,ad5735" },
789 	{ .compatible = "adi,ad5737" },
790 	{ }
791 };
792 MODULE_DEVICE_TABLE(of, ad5755_of_match);
793 
794 static struct spi_driver ad5755_driver = {
795 	.driver = {
796 		.name = "ad5755",
797 	},
798 	.probe = ad5755_probe,
799 	.id_table = ad5755_id,
800 };
801 module_spi_driver(ad5755_driver);
802 
803 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
804 MODULE_DESCRIPTION("Analog Devices AD5755/55-1/57/35/37 DAC");
805 MODULE_LICENSE("GPL v2");
806