xref: /openbmc/linux/drivers/iio/dac/ad5755.c (revision 0a907292)
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  * @lock:	lock to protect the data buffer during SPI ops
86  * @data:	spi transfer buffers
87  */
88 struct ad5755_state {
89 	struct spi_device		*spi;
90 	const struct ad5755_chip_info	*chip_info;
91 	unsigned int			pwr_down;
92 	unsigned int			ctrl[AD5755_NUM_CHANNELS];
93 	struct iio_chan_spec		channels[AD5755_NUM_CHANNELS];
94 	struct mutex			lock;
95 
96 	/*
97 	 * DMA (thus cache coherency maintenance) requires the
98 	 * transfer buffers to live in their own cache lines.
99 	 */
100 
101 	union {
102 		__be32 d32;
103 		u8 d8[4];
104 	} data[2] ____cacheline_aligned;
105 };
106 
107 enum ad5755_type {
108 	ID_AD5755,
109 	ID_AD5757,
110 	ID_AD5735,
111 	ID_AD5737,
112 };
113 
114 #ifdef CONFIG_OF
115 static const int ad5755_dcdc_freq_table[][2] = {
116 	{ 250000, AD5755_DC_DC_FREQ_250kHZ },
117 	{ 410000, AD5755_DC_DC_FREQ_410kHZ },
118 	{ 650000, AD5755_DC_DC_FREQ_650kHZ }
119 };
120 
121 static const int ad5755_dcdc_maxv_table[][2] = {
122 	{ 23000000, AD5755_DC_DC_MAXV_23V },
123 	{ 24500000, AD5755_DC_DC_MAXV_24V5 },
124 	{ 27000000, AD5755_DC_DC_MAXV_27V },
125 	{ 29500000, AD5755_DC_DC_MAXV_29V5 },
126 };
127 
128 static const int ad5755_slew_rate_table[][2] = {
129 	{ 64000, AD5755_SLEW_RATE_64k },
130 	{ 32000, AD5755_SLEW_RATE_32k },
131 	{ 16000, AD5755_SLEW_RATE_16k },
132 	{ 8000, AD5755_SLEW_RATE_8k },
133 	{ 4000, AD5755_SLEW_RATE_4k },
134 	{ 2000, AD5755_SLEW_RATE_2k },
135 	{ 1000, AD5755_SLEW_RATE_1k },
136 	{ 500, AD5755_SLEW_RATE_500 },
137 	{ 250, AD5755_SLEW_RATE_250 },
138 	{ 125, AD5755_SLEW_RATE_125 },
139 	{ 64, AD5755_SLEW_RATE_64 },
140 	{ 32, AD5755_SLEW_RATE_32 },
141 	{ 16, AD5755_SLEW_RATE_16 },
142 	{ 8, AD5755_SLEW_RATE_8 },
143 	{ 4, AD5755_SLEW_RATE_4 },
144 	{ 0, AD5755_SLEW_RATE_0_5 },
145 };
146 
147 static const int ad5755_slew_step_table[][2] = {
148 	{ 256, AD5755_SLEW_STEP_SIZE_256 },
149 	{ 128, AD5755_SLEW_STEP_SIZE_128 },
150 	{ 64, AD5755_SLEW_STEP_SIZE_64 },
151 	{ 32, AD5755_SLEW_STEP_SIZE_32 },
152 	{ 16, AD5755_SLEW_STEP_SIZE_16 },
153 	{ 4, AD5755_SLEW_STEP_SIZE_4 },
154 	{ 2, AD5755_SLEW_STEP_SIZE_2 },
155 	{ 1, AD5755_SLEW_STEP_SIZE_1 },
156 };
157 #endif
158 
159 static int ad5755_write_unlocked(struct iio_dev *indio_dev,
160 	unsigned int reg, unsigned int val)
161 {
162 	struct ad5755_state *st = iio_priv(indio_dev);
163 
164 	st->data[0].d32 = cpu_to_be32((reg << 16) | val);
165 
166 	return spi_write(st->spi, &st->data[0].d8[1], 3);
167 }
168 
169 static int ad5755_write_ctrl_unlocked(struct iio_dev *indio_dev,
170 	unsigned int channel, unsigned int reg, unsigned int val)
171 {
172 	return ad5755_write_unlocked(indio_dev,
173 		AD5755_WRITE_REG_CTRL(channel), (reg << 13) | val);
174 }
175 
176 static int ad5755_write(struct iio_dev *indio_dev, unsigned int reg,
177 	unsigned int val)
178 {
179 	struct ad5755_state *st = iio_priv(indio_dev);
180 	int ret;
181 
182 	mutex_lock(&st->lock);
183 	ret = ad5755_write_unlocked(indio_dev, reg, val);
184 	mutex_unlock(&st->lock);
185 
186 	return ret;
187 }
188 
189 static int ad5755_write_ctrl(struct iio_dev *indio_dev, unsigned int channel,
190 	unsigned int reg, unsigned int val)
191 {
192 	struct ad5755_state *st = iio_priv(indio_dev);
193 	int ret;
194 
195 	mutex_lock(&st->lock);
196 	ret = ad5755_write_ctrl_unlocked(indio_dev, channel, reg, val);
197 	mutex_unlock(&st->lock);
198 
199 	return ret;
200 }
201 
202 static int ad5755_read(struct iio_dev *indio_dev, unsigned int addr)
203 {
204 	struct ad5755_state *st = iio_priv(indio_dev);
205 	int ret;
206 	struct spi_transfer t[] = {
207 		{
208 			.tx_buf = &st->data[0].d8[1],
209 			.len = 3,
210 			.cs_change = 1,
211 		}, {
212 			.tx_buf = &st->data[1].d8[1],
213 			.rx_buf = &st->data[1].d8[1],
214 			.len = 3,
215 		},
216 	};
217 
218 	mutex_lock(&st->lock);
219 
220 	st->data[0].d32 = cpu_to_be32(AD5755_READ_FLAG | (addr << 16));
221 	st->data[1].d32 = cpu_to_be32(AD5755_NOOP);
222 
223 	ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
224 	if (ret >= 0)
225 		ret = be32_to_cpu(st->data[1].d32) & 0xffff;
226 
227 	mutex_unlock(&st->lock);
228 
229 	return ret;
230 }
231 
232 static int ad5755_update_dac_ctrl(struct iio_dev *indio_dev,
233 	unsigned int channel, unsigned int set, unsigned int clr)
234 {
235 	struct ad5755_state *st = iio_priv(indio_dev);
236 	int ret;
237 
238 	st->ctrl[channel] |= set;
239 	st->ctrl[channel] &= ~clr;
240 
241 	ret = ad5755_write_ctrl_unlocked(indio_dev, channel,
242 		AD5755_CTRL_REG_DAC, st->ctrl[channel]);
243 
244 	return ret;
245 }
246 
247 static int ad5755_set_channel_pwr_down(struct iio_dev *indio_dev,
248 	unsigned int channel, bool pwr_down)
249 {
250 	struct ad5755_state *st = iio_priv(indio_dev);
251 	unsigned int mask = BIT(channel);
252 
253 	mutex_lock(&st->lock);
254 
255 	if ((bool)(st->pwr_down & mask) == pwr_down)
256 		goto out_unlock;
257 
258 	if (!pwr_down) {
259 		st->pwr_down &= ~mask;
260 		ad5755_update_dac_ctrl(indio_dev, channel,
261 			AD5755_DAC_INT_EN | AD5755_DAC_DC_DC_EN, 0);
262 		udelay(200);
263 		ad5755_update_dac_ctrl(indio_dev, channel,
264 			AD5755_DAC_OUT_EN, 0);
265 	} else {
266 		st->pwr_down |= mask;
267 		ad5755_update_dac_ctrl(indio_dev, channel,
268 			0, AD5755_DAC_INT_EN | AD5755_DAC_OUT_EN |
269 				AD5755_DAC_DC_DC_EN);
270 	}
271 
272 out_unlock:
273 	mutex_unlock(&st->lock);
274 
275 	return 0;
276 }
277 
278 static const int ad5755_min_max_table[][2] = {
279 	[AD5755_MODE_VOLTAGE_0V_5V] = { 0, 5000 },
280 	[AD5755_MODE_VOLTAGE_0V_10V] = { 0, 10000 },
281 	[AD5755_MODE_VOLTAGE_PLUSMINUS_5V] = { -5000, 5000 },
282 	[AD5755_MODE_VOLTAGE_PLUSMINUS_10V] = { -10000, 10000 },
283 	[AD5755_MODE_CURRENT_4mA_20mA] = { 4, 20 },
284 	[AD5755_MODE_CURRENT_0mA_20mA] = { 0, 20 },
285 	[AD5755_MODE_CURRENT_0mA_24mA] = { 0, 24 },
286 };
287 
288 static void ad5755_get_min_max(struct ad5755_state *st,
289 	struct iio_chan_spec const *chan, int *min, int *max)
290 {
291 	enum ad5755_mode mode = st->ctrl[chan->channel] & 7;
292 	*min = ad5755_min_max_table[mode][0];
293 	*max = ad5755_min_max_table[mode][1];
294 }
295 
296 static inline int ad5755_get_offset(struct ad5755_state *st,
297 	struct iio_chan_spec const *chan)
298 {
299 	int min, max;
300 
301 	ad5755_get_min_max(st, chan, &min, &max);
302 	return (min * (1 << chan->scan_type.realbits)) / (max - min);
303 }
304 
305 static int ad5755_chan_reg_info(struct ad5755_state *st,
306 	struct iio_chan_spec const *chan, long info, bool write,
307 	unsigned int *reg, unsigned int *shift, unsigned int *offset)
308 {
309 	switch (info) {
310 	case IIO_CHAN_INFO_RAW:
311 		if (write)
312 			*reg = AD5755_WRITE_REG_DATA(chan->address);
313 		else
314 			*reg = AD5755_READ_REG_DATA(chan->address);
315 		*shift = chan->scan_type.shift;
316 		*offset = 0;
317 		break;
318 	case IIO_CHAN_INFO_CALIBBIAS:
319 		if (write)
320 			*reg = AD5755_WRITE_REG_OFFSET(chan->address);
321 		else
322 			*reg = AD5755_READ_REG_OFFSET(chan->address);
323 		*shift = st->chip_info->calib_shift;
324 		*offset = 32768;
325 		break;
326 	case IIO_CHAN_INFO_CALIBSCALE:
327 		if (write)
328 			*reg =  AD5755_WRITE_REG_GAIN(chan->address);
329 		else
330 			*reg =  AD5755_READ_REG_GAIN(chan->address);
331 		*shift = st->chip_info->calib_shift;
332 		*offset = 0;
333 		break;
334 	default:
335 		return -EINVAL;
336 	}
337 
338 	return 0;
339 }
340 
341 static int ad5755_read_raw(struct iio_dev *indio_dev,
342 	const struct iio_chan_spec *chan, int *val, int *val2, long info)
343 {
344 	struct ad5755_state *st = iio_priv(indio_dev);
345 	unsigned int reg, shift, offset;
346 	int min, max;
347 	int ret;
348 
349 	switch (info) {
350 	case IIO_CHAN_INFO_SCALE:
351 		ad5755_get_min_max(st, chan, &min, &max);
352 		*val = max - min;
353 		*val2 = chan->scan_type.realbits;
354 		return IIO_VAL_FRACTIONAL_LOG2;
355 	case IIO_CHAN_INFO_OFFSET:
356 		*val = ad5755_get_offset(st, chan);
357 		return IIO_VAL_INT;
358 	default:
359 		ret = ad5755_chan_reg_info(st, chan, info, false,
360 						&reg, &shift, &offset);
361 		if (ret)
362 			return ret;
363 
364 		ret = ad5755_read(indio_dev, reg);
365 		if (ret < 0)
366 			return ret;
367 
368 		*val = (ret - offset) >> shift;
369 
370 		return IIO_VAL_INT;
371 	}
372 
373 	return -EINVAL;
374 }
375 
376 static int ad5755_write_raw(struct iio_dev *indio_dev,
377 	const struct iio_chan_spec *chan, int val, int val2, long info)
378 {
379 	struct ad5755_state *st = iio_priv(indio_dev);
380 	unsigned int shift, reg, offset;
381 	int ret;
382 
383 	ret = ad5755_chan_reg_info(st, chan, info, true,
384 					&reg, &shift, &offset);
385 	if (ret)
386 		return ret;
387 
388 	val <<= shift;
389 	val += offset;
390 
391 	if (val < 0 || val > 0xffff)
392 		return -EINVAL;
393 
394 	return ad5755_write(indio_dev, reg, val);
395 }
396 
397 static ssize_t ad5755_read_powerdown(struct iio_dev *indio_dev, uintptr_t priv,
398 	const struct iio_chan_spec *chan, char *buf)
399 {
400 	struct ad5755_state *st = iio_priv(indio_dev);
401 
402 	return sysfs_emit(buf, "%d\n",
403 			  (bool)(st->pwr_down & (1 << chan->channel)));
404 }
405 
406 static ssize_t ad5755_write_powerdown(struct iio_dev *indio_dev, uintptr_t priv,
407 	struct iio_chan_spec const *chan, const char *buf, size_t len)
408 {
409 	bool pwr_down;
410 	int ret;
411 
412 	ret = strtobool(buf, &pwr_down);
413 	if (ret)
414 		return ret;
415 
416 	ret = ad5755_set_channel_pwr_down(indio_dev, chan->channel, pwr_down);
417 	return ret ? ret : len;
418 }
419 
420 static const struct iio_info ad5755_info = {
421 	.read_raw = ad5755_read_raw,
422 	.write_raw = ad5755_write_raw,
423 };
424 
425 static const struct iio_chan_spec_ext_info ad5755_ext_info[] = {
426 	{
427 		.name = "powerdown",
428 		.read = ad5755_read_powerdown,
429 		.write = ad5755_write_powerdown,
430 		.shared = IIO_SEPARATE,
431 	},
432 	{ },
433 };
434 
435 #define AD5755_CHANNEL(_bits) {					\
436 	.indexed = 1,						\
437 	.output = 1,						\
438 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
439 		BIT(IIO_CHAN_INFO_SCALE) |			\
440 		BIT(IIO_CHAN_INFO_OFFSET) |			\
441 		BIT(IIO_CHAN_INFO_CALIBSCALE) |			\
442 		BIT(IIO_CHAN_INFO_CALIBBIAS),			\
443 	.scan_type = {						\
444 		.sign = 'u',					\
445 		.realbits = (_bits),				\
446 		.storagebits = 16,				\
447 		.shift = 16 - (_bits),				\
448 	},							\
449 	.ext_info = ad5755_ext_info,				\
450 }
451 
452 static const struct ad5755_chip_info ad5755_chip_info_tbl[] = {
453 	[ID_AD5735] = {
454 		.channel_template = AD5755_CHANNEL(14),
455 		.has_voltage_out = true,
456 		.calib_shift = 4,
457 	},
458 	[ID_AD5737] = {
459 		.channel_template = AD5755_CHANNEL(14),
460 		.has_voltage_out = false,
461 		.calib_shift = 4,
462 	},
463 	[ID_AD5755] = {
464 		.channel_template = AD5755_CHANNEL(16),
465 		.has_voltage_out = true,
466 		.calib_shift = 0,
467 	},
468 	[ID_AD5757] = {
469 		.channel_template = AD5755_CHANNEL(16),
470 		.has_voltage_out = false,
471 		.calib_shift = 0,
472 	},
473 };
474 
475 static bool ad5755_is_valid_mode(struct ad5755_state *st, enum ad5755_mode mode)
476 {
477 	switch (mode) {
478 	case AD5755_MODE_VOLTAGE_0V_5V:
479 	case AD5755_MODE_VOLTAGE_0V_10V:
480 	case AD5755_MODE_VOLTAGE_PLUSMINUS_5V:
481 	case AD5755_MODE_VOLTAGE_PLUSMINUS_10V:
482 		return st->chip_info->has_voltage_out;
483 	case AD5755_MODE_CURRENT_4mA_20mA:
484 	case AD5755_MODE_CURRENT_0mA_20mA:
485 	case AD5755_MODE_CURRENT_0mA_24mA:
486 		return true;
487 	default:
488 		return false;
489 	}
490 }
491 
492 static int ad5755_setup_pdata(struct iio_dev *indio_dev,
493 			      const struct ad5755_platform_data *pdata)
494 {
495 	struct ad5755_state *st = iio_priv(indio_dev);
496 	unsigned int val;
497 	unsigned int i;
498 	int ret;
499 
500 	if (pdata->dc_dc_phase > AD5755_DC_DC_PHASE_90_DEGREE ||
501 		pdata->dc_dc_freq > AD5755_DC_DC_FREQ_650kHZ ||
502 		pdata->dc_dc_maxv > AD5755_DC_DC_MAXV_29V5)
503 		return -EINVAL;
504 
505 	val = pdata->dc_dc_maxv << AD5755_DC_DC_MAXV;
506 	val |= pdata->dc_dc_freq << AD5755_DC_DC_FREQ_SHIFT;
507 	val |= pdata->dc_dc_phase << AD5755_DC_DC_PHASE_SHIFT;
508 	if (pdata->ext_dc_dc_compenstation_resistor)
509 		val |= AD5755_EXT_DC_DC_COMP_RES;
510 
511 	ret = ad5755_write_ctrl(indio_dev, 0, AD5755_CTRL_REG_DC_DC, val);
512 	if (ret < 0)
513 		return ret;
514 
515 	for (i = 0; i < ARRAY_SIZE(pdata->dac); ++i) {
516 		val = pdata->dac[i].slew.step_size <<
517 			AD5755_SLEW_STEP_SIZE_SHIFT;
518 		val |= pdata->dac[i].slew.rate <<
519 			AD5755_SLEW_RATE_SHIFT;
520 		if (pdata->dac[i].slew.enable)
521 			val |= AD5755_SLEW_ENABLE;
522 
523 		ret = ad5755_write_ctrl(indio_dev, i,
524 					AD5755_CTRL_REG_SLEW, val);
525 		if (ret < 0)
526 			return ret;
527 	}
528 
529 	for (i = 0; i < ARRAY_SIZE(pdata->dac); ++i) {
530 		if (!ad5755_is_valid_mode(st, pdata->dac[i].mode))
531 			return -EINVAL;
532 
533 		val = 0;
534 		if (!pdata->dac[i].ext_current_sense_resistor)
535 			val |= AD5755_DAC_INT_CURRENT_SENSE_RESISTOR;
536 		if (pdata->dac[i].enable_voltage_overrange)
537 			val |= AD5755_DAC_VOLTAGE_OVERRANGE_EN;
538 		val |= pdata->dac[i].mode;
539 
540 		ret = ad5755_update_dac_ctrl(indio_dev, i, val, 0);
541 		if (ret < 0)
542 			return ret;
543 	}
544 
545 	return 0;
546 }
547 
548 static bool ad5755_is_voltage_mode(enum ad5755_mode mode)
549 {
550 	switch (mode) {
551 	case AD5755_MODE_VOLTAGE_0V_5V:
552 	case AD5755_MODE_VOLTAGE_0V_10V:
553 	case AD5755_MODE_VOLTAGE_PLUSMINUS_5V:
554 	case AD5755_MODE_VOLTAGE_PLUSMINUS_10V:
555 		return true;
556 	default:
557 		return false;
558 	}
559 }
560 
561 static int ad5755_init_channels(struct iio_dev *indio_dev,
562 				const struct ad5755_platform_data *pdata)
563 {
564 	struct ad5755_state *st = iio_priv(indio_dev);
565 	struct iio_chan_spec *channels = st->channels;
566 	unsigned int i;
567 
568 	for (i = 0; i < AD5755_NUM_CHANNELS; ++i) {
569 		channels[i] = st->chip_info->channel_template;
570 		channels[i].channel = i;
571 		channels[i].address = i;
572 		if (pdata && ad5755_is_voltage_mode(pdata->dac[i].mode))
573 			channels[i].type = IIO_VOLTAGE;
574 		else
575 			channels[i].type = IIO_CURRENT;
576 	}
577 
578 	indio_dev->channels = channels;
579 
580 	return 0;
581 }
582 
583 #define AD5755_DEFAULT_DAC_PDATA { \
584 		.mode = AD5755_MODE_CURRENT_4mA_20mA, \
585 		.ext_current_sense_resistor = true, \
586 		.enable_voltage_overrange = false, \
587 		.slew = { \
588 			.enable = false, \
589 			.rate = AD5755_SLEW_RATE_64k, \
590 			.step_size = AD5755_SLEW_STEP_SIZE_1, \
591 		}, \
592 	}
593 
594 static const struct ad5755_platform_data ad5755_default_pdata = {
595 	.ext_dc_dc_compenstation_resistor = false,
596 	.dc_dc_phase = AD5755_DC_DC_PHASE_ALL_SAME_EDGE,
597 	.dc_dc_freq = AD5755_DC_DC_FREQ_410kHZ,
598 	.dc_dc_maxv = AD5755_DC_DC_MAXV_23V,
599 	.dac = {
600 		[0] = AD5755_DEFAULT_DAC_PDATA,
601 		[1] = AD5755_DEFAULT_DAC_PDATA,
602 		[2] = AD5755_DEFAULT_DAC_PDATA,
603 		[3] = AD5755_DEFAULT_DAC_PDATA,
604 	},
605 };
606 
607 #ifdef CONFIG_OF
608 static struct ad5755_platform_data *ad5755_parse_dt(struct device *dev)
609 {
610 	struct device_node *np = dev->of_node;
611 	struct device_node *pp;
612 	struct ad5755_platform_data *pdata;
613 	unsigned int tmp;
614 	unsigned int tmparray[3];
615 	int devnr, i;
616 
617 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
618 	if (!pdata)
619 		return NULL;
620 
621 	pdata->ext_dc_dc_compenstation_resistor =
622 	    of_property_read_bool(np, "adi,ext-dc-dc-compenstation-resistor");
623 
624 	if (!of_property_read_u32(np, "adi,dc-dc-phase", &tmp))
625 		pdata->dc_dc_phase = tmp;
626 	else
627 		pdata->dc_dc_phase = AD5755_DC_DC_PHASE_ALL_SAME_EDGE;
628 
629 	pdata->dc_dc_freq = AD5755_DC_DC_FREQ_410kHZ;
630 	if (!of_property_read_u32(np, "adi,dc-dc-freq-hz", &tmp)) {
631 		for (i = 0; i < ARRAY_SIZE(ad5755_dcdc_freq_table); i++) {
632 			if (tmp == ad5755_dcdc_freq_table[i][0]) {
633 				pdata->dc_dc_freq = ad5755_dcdc_freq_table[i][1];
634 				break;
635 			}
636 		}
637 
638 		if (i == ARRAY_SIZE(ad5755_dcdc_freq_table))
639 			dev_err(dev,
640 				"adi,dc-dc-freq out of range selecting 410kHz\n");
641 	}
642 
643 	pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_23V;
644 	if (!of_property_read_u32(np, "adi,dc-dc-max-microvolt", &tmp)) {
645 		for (i = 0; i < ARRAY_SIZE(ad5755_dcdc_maxv_table); i++) {
646 			if (tmp == ad5755_dcdc_maxv_table[i][0]) {
647 				pdata->dc_dc_maxv = ad5755_dcdc_maxv_table[i][1];
648 				break;
649 			}
650 		}
651 		if (i == ARRAY_SIZE(ad5755_dcdc_maxv_table))
652 				dev_err(dev,
653 					"adi,dc-dc-maxv out of range selecting 23V\n");
654 	}
655 
656 	devnr = 0;
657 	for_each_child_of_node(np, pp) {
658 		if (devnr >= AD5755_NUM_CHANNELS) {
659 			dev_err(dev,
660 				"There are too many channels defined in DT\n");
661 			goto error_out;
662 		}
663 
664 		if (!of_property_read_u32(pp, "adi,mode", &tmp))
665 			pdata->dac[devnr].mode = tmp;
666 		else
667 			pdata->dac[devnr].mode = AD5755_MODE_CURRENT_4mA_20mA;
668 
669 		pdata->dac[devnr].ext_current_sense_resistor =
670 		    of_property_read_bool(pp, "adi,ext-current-sense-resistor");
671 
672 		pdata->dac[devnr].enable_voltage_overrange =
673 		    of_property_read_bool(pp, "adi,enable-voltage-overrange");
674 
675 		if (!of_property_read_u32_array(pp, "adi,slew", tmparray, 3)) {
676 			pdata->dac[devnr].slew.enable = tmparray[0];
677 
678 			pdata->dac[devnr].slew.rate = AD5755_SLEW_RATE_64k;
679 			for (i = 0; i < ARRAY_SIZE(ad5755_slew_rate_table); i++) {
680 				if (tmparray[1] == ad5755_slew_rate_table[i][0]) {
681 					pdata->dac[devnr].slew.rate =
682 						ad5755_slew_rate_table[i][1];
683 					break;
684 				}
685 			}
686 			if (i == ARRAY_SIZE(ad5755_slew_rate_table))
687 				dev_err(dev,
688 					"channel %d slew rate out of range selecting 64kHz\n",
689 					devnr);
690 
691 			pdata->dac[devnr].slew.step_size = AD5755_SLEW_STEP_SIZE_1;
692 			for (i = 0; i < ARRAY_SIZE(ad5755_slew_step_table); i++) {
693 				if (tmparray[2] == ad5755_slew_step_table[i][0]) {
694 					pdata->dac[devnr].slew.step_size =
695 						ad5755_slew_step_table[i][1];
696 					break;
697 				}
698 			}
699 			if (i == ARRAY_SIZE(ad5755_slew_step_table))
700 				dev_err(dev,
701 					"channel %d slew step size out of range selecting 1 LSB\n",
702 					devnr);
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->name = spi_get_device_id(spi)->name;
748 	indio_dev->info = &ad5755_info;
749 	indio_dev->modes = INDIO_DIRECT_MODE;
750 	indio_dev->num_channels = AD5755_NUM_CHANNELS;
751 
752 	mutex_init(&st->lock);
753 
754 	if (spi->dev.of_node)
755 		pdata = ad5755_parse_dt(&spi->dev);
756 	else
757 		pdata = spi->dev.platform_data;
758 
759 	if (!pdata) {
760 		dev_warn(&spi->dev, "no platform data? using default\n");
761 		pdata = &ad5755_default_pdata;
762 	}
763 
764 	ret = ad5755_init_channels(indio_dev, pdata);
765 	if (ret)
766 		return ret;
767 
768 	ret = ad5755_setup_pdata(indio_dev, pdata);
769 	if (ret)
770 		return ret;
771 
772 	return devm_iio_device_register(&spi->dev, indio_dev);
773 }
774 
775 static const struct spi_device_id ad5755_id[] = {
776 	{ "ad5755", ID_AD5755 },
777 	{ "ad5755-1", ID_AD5755 },
778 	{ "ad5757", ID_AD5757 },
779 	{ "ad5735", ID_AD5735 },
780 	{ "ad5737", ID_AD5737 },
781 	{}
782 };
783 MODULE_DEVICE_TABLE(spi, ad5755_id);
784 
785 static const struct of_device_id ad5755_of_match[] = {
786 	{ .compatible = "adi,ad5755" },
787 	{ .compatible = "adi,ad5755-1" },
788 	{ .compatible = "adi,ad5757" },
789 	{ .compatible = "adi,ad5735" },
790 	{ .compatible = "adi,ad5737" },
791 	{ }
792 };
793 MODULE_DEVICE_TABLE(of, ad5755_of_match);
794 
795 static struct spi_driver ad5755_driver = {
796 	.driver = {
797 		.name = "ad5755",
798 	},
799 	.probe = ad5755_probe,
800 	.id_table = ad5755_id,
801 };
802 module_spi_driver(ad5755_driver);
803 
804 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
805 MODULE_DESCRIPTION("Analog Devices AD5755/55-1/57/35/37 DAC");
806 MODULE_LICENSE("GPL v2");
807