xref: /openbmc/linux/drivers/iio/dac/ad5758.c (revision 045f77ba)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * AD5758 Digital to analog converters driver
4  *
5  * Copyright 2018 Analog Devices Inc.
6  *
7  * TODO: Currently CRC is not supported in this driver
8  */
9 #include <linux/bsearch.h>
10 #include <linux/delay.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/property.h>
14 #include <linux/spi/spi.h>
15 
16 #include <linux/iio/iio.h>
17 #include <linux/iio/sysfs.h>
18 
19 /* AD5758 registers definition */
20 #define AD5758_NOP				0x00
21 #define AD5758_DAC_INPUT			0x01
22 #define AD5758_DAC_OUTPUT			0x02
23 #define AD5758_CLEAR_CODE			0x03
24 #define AD5758_USER_GAIN			0x04
25 #define AD5758_USER_OFFSET			0x05
26 #define AD5758_DAC_CONFIG			0x06
27 #define AD5758_SW_LDAC				0x07
28 #define AD5758_KEY				0x08
29 #define AD5758_GP_CONFIG1			0x09
30 #define AD5758_GP_CONFIG2			0x0A
31 #define AD5758_DCDC_CONFIG1			0x0B
32 #define AD5758_DCDC_CONFIG2			0x0C
33 #define AD5758_WDT_CONFIG			0x0F
34 #define AD5758_DIGITAL_DIAG_CONFIG		0x10
35 #define AD5758_ADC_CONFIG			0x11
36 #define AD5758_FAULT_PIN_CONFIG			0x12
37 #define AD5758_TWO_STAGE_READBACK_SELECT	0x13
38 #define AD5758_DIGITAL_DIAG_RESULTS		0x14
39 #define AD5758_ANALOG_DIAG_RESULTS		0x15
40 #define AD5758_STATUS				0x16
41 #define AD5758_CHIP_ID				0x17
42 #define AD5758_FREQ_MONITOR			0x18
43 #define AD5758_DEVICE_ID_0			0x19
44 #define AD5758_DEVICE_ID_1			0x1A
45 #define AD5758_DEVICE_ID_2			0x1B
46 #define AD5758_DEVICE_ID_3			0x1C
47 
48 /* AD5758_DAC_CONFIG */
49 #define AD5758_DAC_CONFIG_RANGE_MSK		GENMASK(3, 0)
50 #define AD5758_DAC_CONFIG_RANGE_MODE(x)		(((x) & 0xF) << 0)
51 #define AD5758_DAC_CONFIG_INT_EN_MSK		BIT(5)
52 #define AD5758_DAC_CONFIG_INT_EN_MODE(x)	(((x) & 0x1) << 5)
53 #define AD5758_DAC_CONFIG_OUT_EN_MSK		BIT(6)
54 #define AD5758_DAC_CONFIG_OUT_EN_MODE(x)	(((x) & 0x1) << 6)
55 #define AD5758_DAC_CONFIG_SR_EN_MSK		BIT(8)
56 #define AD5758_DAC_CONFIG_SR_EN_MODE(x)		(((x) & 0x1) << 8)
57 #define AD5758_DAC_CONFIG_SR_CLOCK_MSK		GENMASK(12, 9)
58 #define AD5758_DAC_CONFIG_SR_CLOCK_MODE(x)	(((x) & 0xF) << 9)
59 #define AD5758_DAC_CONFIG_SR_STEP_MSK		GENMASK(15, 13)
60 #define AD5758_DAC_CONFIG_SR_STEP_MODE(x)	(((x) & 0x7) << 13)
61 
62 /* AD5758_KEY */
63 #define AD5758_KEY_CODE_RESET_1			0x15FA
64 #define AD5758_KEY_CODE_RESET_2			0xAF51
65 #define AD5758_KEY_CODE_SINGLE_ADC_CONV		0x1ADC
66 #define AD5758_KEY_CODE_RESET_WDT		0x0D06
67 #define AD5758_KEY_CODE_CALIB_MEM_REFRESH	0xFCBA
68 
69 /* AD5758_DCDC_CONFIG1 */
70 #define AD5758_DCDC_CONFIG1_DCDC_VPROG_MSK	GENMASK(4, 0)
71 #define AD5758_DCDC_CONFIG1_DCDC_VPROG_MODE(x)	(((x) & 0x1F) << 0)
72 #define AD5758_DCDC_CONFIG1_DCDC_MODE_MSK	GENMASK(6, 5)
73 #define AD5758_DCDC_CONFIG1_DCDC_MODE_MODE(x)	(((x) & 0x3) << 5)
74 #define AD5758_DCDC_CONFIG1_PROT_SW_EN_MSK	BIT(7)
75 #define AD5758_DCDC_CONFIG1_PROT_SW_EN_MODE(x)	(((x) & 0x1) << 7)
76 
77 /* AD5758_DCDC_CONFIG2 */
78 #define AD5758_DCDC_CONFIG2_ILIMIT_MSK		GENMASK(3, 1)
79 #define AD5758_DCDC_CONFIG2_ILIMIT_MODE(x)	(((x) & 0x7) << 1)
80 #define AD5758_DCDC_CONFIG2_INTR_SAT_3WI_MSK	BIT(11)
81 #define AD5758_DCDC_CONFIG2_BUSY_3WI_MSK	BIT(12)
82 
83 /* AD5758_DIGITAL_DIAG_RESULTS */
84 #define AD5758_CAL_MEM_UNREFRESHED_MSK		BIT(15)
85 
86 #define AD5758_WR_FLAG_MSK(x)		(0x80 | ((x) & 0x1F))
87 
88 #define AD5758_FULL_SCALE_MICRO	65535000000ULL
89 
90 /**
91  * struct ad5758_state - driver instance specific data
92  * @spi:	spi_device
93  * @lock:	mutex lock
94  * @out_range:	struct which stores the output range
95  * @dc_dc_mode:	variable which stores the mode of operation
96  * @dc_dc_ilim:	variable which stores the dc-to-dc converter current limit
97  * @slew_time:	variable which stores the target slew time
98  * @pwr_down:	variable which contains whether a channel is powered down or not
99  * @data:	spi transfer buffers
100  */
101 
102 struct ad5758_range {
103 	int reg;
104 	int min;
105 	int max;
106 };
107 
108 struct ad5758_state {
109 	struct spi_device *spi;
110 	struct mutex lock;
111 	struct ad5758_range out_range;
112 	unsigned int dc_dc_mode;
113 	unsigned int dc_dc_ilim;
114 	unsigned int slew_time;
115 	bool pwr_down;
116 	__be32 d32[3];
117 };
118 
119 /**
120  * Output ranges corresponding to bits [3:0] from DAC_CONFIG register
121  * 0000: 0 V to 5 V voltage range
122  * 0001: 0 V to 10 V voltage range
123  * 0010: ±5 V voltage range
124  * 0011: ±10 V voltage range
125  * 1000: 0 mA to 20 mA current range
126  * 1001: 0 mA to 24 mA current range
127  * 1010: 4 mA to 20 mA current range
128  * 1011: ±20 mA current range
129  * 1100: ±24 mA current range
130  * 1101: -1 mA to +22 mA current range
131  */
132 enum ad5758_output_range {
133 	AD5758_RANGE_0V_5V,
134 	AD5758_RANGE_0V_10V,
135 	AD5758_RANGE_PLUSMINUS_5V,
136 	AD5758_RANGE_PLUSMINUS_10V,
137 	AD5758_RANGE_0mA_20mA = 8,
138 	AD5758_RANGE_0mA_24mA,
139 	AD5758_RANGE_4mA_24mA,
140 	AD5758_RANGE_PLUSMINUS_20mA,
141 	AD5758_RANGE_PLUSMINUS_24mA,
142 	AD5758_RANGE_MINUS_1mA_PLUS_22mA,
143 };
144 
145 enum ad5758_dc_dc_mode {
146 	AD5758_DCDC_MODE_POWER_OFF,
147 	AD5758_DCDC_MODE_DPC_CURRENT,
148 	AD5758_DCDC_MODE_DPC_VOLTAGE,
149 	AD5758_DCDC_MODE_PPC_CURRENT,
150 };
151 
152 static const struct ad5758_range ad5758_voltage_range[] = {
153 	{ AD5758_RANGE_0V_5V, 0, 5000000 },
154 	{ AD5758_RANGE_0V_10V, 0, 10000000 },
155 	{ AD5758_RANGE_PLUSMINUS_5V, -5000000, 5000000 },
156 	{ AD5758_RANGE_PLUSMINUS_10V, -10000000, 10000000 }
157 };
158 
159 static const struct ad5758_range ad5758_current_range[] = {
160 	{ AD5758_RANGE_0mA_20mA, 0, 20000},
161 	{ AD5758_RANGE_0mA_24mA, 0, 24000 },
162 	{ AD5758_RANGE_4mA_24mA, 4, 24000 },
163 	{ AD5758_RANGE_PLUSMINUS_20mA, -20000, 20000 },
164 	{ AD5758_RANGE_PLUSMINUS_24mA, -24000, 24000 },
165 	{ AD5758_RANGE_MINUS_1mA_PLUS_22mA, -1000, 22000 },
166 };
167 
168 static const int ad5758_sr_clk[16] = {
169 	240000, 200000, 150000, 128000, 64000, 32000, 16000, 8000, 4000, 2000,
170 	1000, 512, 256, 128, 64, 16
171 };
172 
173 static const int ad5758_sr_step[8] = {
174 	4, 12, 64, 120, 256, 500, 1820, 2048
175 };
176 
177 static const int ad5758_dc_dc_ilim[6] = {
178 	150000, 200000, 250000, 300000, 350000, 400000
179 };
180 
181 static int ad5758_spi_reg_read(struct ad5758_state *st, unsigned int addr)
182 {
183 	struct spi_transfer t[] = {
184 		{
185 			.tx_buf = &st->d32[0],
186 			.len = 4,
187 			.cs_change = 1,
188 		}, {
189 			.tx_buf = &st->d32[1],
190 			.rx_buf = &st->d32[2],
191 			.len = 4,
192 		},
193 	};
194 	int ret;
195 
196 	st->d32[0] = cpu_to_be32(
197 		(AD5758_WR_FLAG_MSK(AD5758_TWO_STAGE_READBACK_SELECT) << 24) |
198 		(addr << 8));
199 	st->d32[1] = cpu_to_be32(AD5758_WR_FLAG_MSK(AD5758_NOP) << 24);
200 
201 	ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
202 	if (ret < 0)
203 		return ret;
204 
205 	return (be32_to_cpu(st->d32[2]) >> 8) & 0xFFFF;
206 }
207 
208 static int ad5758_spi_reg_write(struct ad5758_state *st,
209 				unsigned int addr,
210 				unsigned int val)
211 {
212 	st->d32[0] = cpu_to_be32((AD5758_WR_FLAG_MSK(addr) << 24) |
213 				 ((val & 0xFFFF) << 8));
214 
215 	return spi_write(st->spi, &st->d32[0], sizeof(st->d32[0]));
216 }
217 
218 static int ad5758_spi_write_mask(struct ad5758_state *st,
219 				 unsigned int addr,
220 				 unsigned long int mask,
221 				 unsigned int val)
222 {
223 	int regval;
224 
225 	regval = ad5758_spi_reg_read(st, addr);
226 	if (regval < 0)
227 		return regval;
228 
229 	regval &= ~mask;
230 	regval |= val;
231 
232 	return ad5758_spi_reg_write(st, addr, regval);
233 }
234 
235 static int cmpfunc(const void *a, const void *b)
236 {
237 	return *(int *)a - *(int *)b;
238 }
239 
240 static int ad5758_find_closest_match(const int *array,
241 				     unsigned int size, int val)
242 {
243 	int i;
244 
245 	for (i = 0; i < size; i++) {
246 		if (val <= array[i])
247 			return i;
248 	}
249 
250 	return size - 1;
251 }
252 
253 static int ad5758_wait_for_task_complete(struct ad5758_state *st,
254 					 unsigned int reg,
255 					 unsigned int mask)
256 {
257 	unsigned int timeout;
258 	int ret;
259 
260 	timeout = 10;
261 	do {
262 		ret = ad5758_spi_reg_read(st, reg);
263 		if (ret < 0)
264 			return ret;
265 
266 		if (!(ret & mask))
267 			return 0;
268 
269 		usleep_range(100, 1000);
270 	} while (--timeout);
271 
272 	dev_err(&st->spi->dev,
273 		"Error reading bit 0x%x in 0x%x register\n", mask, reg);
274 
275 	return -EIO;
276 }
277 
278 static int ad5758_calib_mem_refresh(struct ad5758_state *st)
279 {
280 	int ret;
281 
282 	ret = ad5758_spi_reg_write(st, AD5758_KEY,
283 				   AD5758_KEY_CODE_CALIB_MEM_REFRESH);
284 	if (ret < 0) {
285 		dev_err(&st->spi->dev,
286 			"Failed to initiate a calibration memory refresh\n");
287 		return ret;
288 	}
289 
290 	/* Wait to allow time for the internal calibrations to complete */
291 	return ad5758_wait_for_task_complete(st, AD5758_DIGITAL_DIAG_RESULTS,
292 					     AD5758_CAL_MEM_UNREFRESHED_MSK);
293 }
294 
295 static int ad5758_soft_reset(struct ad5758_state *st)
296 {
297 	int ret;
298 
299 	ret = ad5758_spi_reg_write(st, AD5758_KEY, AD5758_KEY_CODE_RESET_1);
300 	if (ret < 0)
301 		return ret;
302 
303 	ret = ad5758_spi_reg_write(st, AD5758_KEY, AD5758_KEY_CODE_RESET_2);
304 
305 	/* Perform a software reset and wait at least 100us */
306 	usleep_range(100, 1000);
307 
308 	return ret;
309 }
310 
311 static int ad5758_set_dc_dc_conv_mode(struct ad5758_state *st,
312 				      enum ad5758_dc_dc_mode mode)
313 {
314 	int ret;
315 
316 	ret = ad5758_spi_write_mask(st, AD5758_DCDC_CONFIG1,
317 				    AD5758_DCDC_CONFIG1_DCDC_MODE_MSK,
318 				    AD5758_DCDC_CONFIG1_DCDC_MODE_MODE(mode));
319 	if (ret < 0)
320 		return ret;
321 
322 	/*
323 	 * Poll the BUSY_3WI bit in the DCDC_CONFIG2 register until it is 0.
324 	 * This allows the 3-wire interface communication to complete.
325 	 */
326 	ret = ad5758_wait_for_task_complete(st, AD5758_DCDC_CONFIG2,
327 					    AD5758_DCDC_CONFIG2_BUSY_3WI_MSK);
328 	if (ret < 0)
329 		return ret;
330 
331 	st->dc_dc_mode = mode;
332 
333 	return ret;
334 }
335 
336 static int ad5758_set_dc_dc_ilim(struct ad5758_state *st, unsigned int ilim)
337 {
338 	int ret;
339 
340 	ret = ad5758_spi_write_mask(st, AD5758_DCDC_CONFIG2,
341 				    AD5758_DCDC_CONFIG2_ILIMIT_MSK,
342 				    AD5758_DCDC_CONFIG2_ILIMIT_MODE(ilim));
343 	if (ret < 0)
344 		return ret;
345 	/*
346 	 * Poll the BUSY_3WI bit in the DCDC_CONFIG2 register until it is 0.
347 	 * This allows the 3-wire interface communication to complete.
348 	 */
349 	return ad5758_wait_for_task_complete(st, AD5758_DCDC_CONFIG2,
350 					     AD5758_DCDC_CONFIG2_BUSY_3WI_MSK);
351 }
352 
353 static int ad5758_slew_rate_set(struct ad5758_state *st,
354 				unsigned int sr_clk_idx,
355 				unsigned int sr_step_idx)
356 {
357 	unsigned int mode;
358 	unsigned long int mask;
359 	int ret;
360 
361 	mask = AD5758_DAC_CONFIG_SR_EN_MSK |
362 	       AD5758_DAC_CONFIG_SR_CLOCK_MSK |
363 	       AD5758_DAC_CONFIG_SR_STEP_MSK;
364 	mode = AD5758_DAC_CONFIG_SR_EN_MODE(1) |
365 	       AD5758_DAC_CONFIG_SR_STEP_MODE(sr_step_idx) |
366 	       AD5758_DAC_CONFIG_SR_CLOCK_MODE(sr_clk_idx);
367 
368 	ret = ad5758_spi_write_mask(st, AD5758_DAC_CONFIG, mask, mode);
369 	if (ret < 0)
370 		return ret;
371 
372 	/* Wait to allow time for the internal calibrations to complete */
373 	return ad5758_wait_for_task_complete(st, AD5758_DIGITAL_DIAG_RESULTS,
374 					     AD5758_CAL_MEM_UNREFRESHED_MSK);
375 }
376 
377 static int ad5758_slew_rate_config(struct ad5758_state *st)
378 {
379 	unsigned int sr_clk_idx, sr_step_idx;
380 	int i, res;
381 	s64 diff_new, diff_old;
382 	u64 sr_step, calc_slew_time;
383 
384 	sr_clk_idx = 0;
385 	sr_step_idx = 0;
386 	diff_old = S64_MAX;
387 	/*
388 	 * The slew time can be determined by using the formula:
389 	 * Slew Time = (Full Scale Out / (Step Size x Update Clk Freq))
390 	 * where Slew time is expressed in microseconds
391 	 * Given the desired slew time, the following algorithm determines the
392 	 * best match for the step size and the update clock frequency.
393 	 */
394 	for (i = 0; i < ARRAY_SIZE(ad5758_sr_clk); i++) {
395 		/*
396 		 * Go through each valid update clock freq and determine a raw
397 		 * value for the step size by using the formula:
398 		 * Step Size = Full Scale Out / (Update Clk Freq * Slew Time)
399 		 */
400 		sr_step = AD5758_FULL_SCALE_MICRO;
401 		do_div(sr_step, ad5758_sr_clk[i]);
402 		do_div(sr_step, st->slew_time);
403 		/*
404 		 * After a raw value for step size was determined, find the
405 		 * closest valid match
406 		 */
407 		res = ad5758_find_closest_match(ad5758_sr_step,
408 						ARRAY_SIZE(ad5758_sr_step),
409 						sr_step);
410 		/* Calculate the slew time */
411 		calc_slew_time = AD5758_FULL_SCALE_MICRO;
412 		do_div(calc_slew_time, ad5758_sr_step[res]);
413 		do_div(calc_slew_time, ad5758_sr_clk[i]);
414 		/*
415 		 * Determine with how many microseconds the calculated slew time
416 		 * is different from the desired slew time and store the diff
417 		 * for the next iteration
418 		 */
419 		diff_new = abs(st->slew_time - calc_slew_time);
420 		if (diff_new < diff_old) {
421 			diff_old = diff_new;
422 			sr_clk_idx = i;
423 			sr_step_idx = res;
424 		}
425 	}
426 
427 	return ad5758_slew_rate_set(st, sr_clk_idx, sr_step_idx);
428 }
429 
430 static int ad5758_set_out_range(struct ad5758_state *st, int range)
431 {
432 	int ret;
433 
434 	ret = ad5758_spi_write_mask(st, AD5758_DAC_CONFIG,
435 				    AD5758_DAC_CONFIG_RANGE_MSK,
436 				    AD5758_DAC_CONFIG_RANGE_MODE(range));
437 	if (ret < 0)
438 		return ret;
439 
440 	/* Wait to allow time for the internal calibrations to complete */
441 	return ad5758_wait_for_task_complete(st, AD5758_DIGITAL_DIAG_RESULTS,
442 					     AD5758_CAL_MEM_UNREFRESHED_MSK);
443 }
444 
445 static int ad5758_fault_prot_switch_en(struct ad5758_state *st, bool enable)
446 {
447 	int ret;
448 
449 	ret = ad5758_spi_write_mask(st, AD5758_DCDC_CONFIG1,
450 			AD5758_DCDC_CONFIG1_PROT_SW_EN_MSK,
451 			AD5758_DCDC_CONFIG1_PROT_SW_EN_MODE(enable));
452 	if (ret < 0)
453 		return ret;
454 	/*
455 	 * Poll the BUSY_3WI bit in the DCDC_CONFIG2 register until it is 0.
456 	 * This allows the 3-wire interface communication to complete.
457 	 */
458 	return ad5758_wait_for_task_complete(st, AD5758_DCDC_CONFIG2,
459 					     AD5758_DCDC_CONFIG2_BUSY_3WI_MSK);
460 }
461 
462 static int ad5758_internal_buffers_en(struct ad5758_state *st, bool enable)
463 {
464 	int ret;
465 
466 	ret = ad5758_spi_write_mask(st, AD5758_DAC_CONFIG,
467 				    AD5758_DAC_CONFIG_INT_EN_MSK,
468 				    AD5758_DAC_CONFIG_INT_EN_MODE(enable));
469 	if (ret < 0)
470 		return ret;
471 
472 	/* Wait to allow time for the internal calibrations to complete */
473 	return ad5758_wait_for_task_complete(st, AD5758_DIGITAL_DIAG_RESULTS,
474 					     AD5758_CAL_MEM_UNREFRESHED_MSK);
475 }
476 
477 static int ad5758_reg_access(struct iio_dev *indio_dev,
478 			     unsigned int reg,
479 			     unsigned int writeval,
480 			     unsigned int *readval)
481 {
482 	struct ad5758_state *st = iio_priv(indio_dev);
483 	int ret;
484 
485 	mutex_lock(&st->lock);
486 	if (readval) {
487 		ret = ad5758_spi_reg_read(st, reg);
488 		if (ret < 0) {
489 			mutex_unlock(&st->lock);
490 			return ret;
491 		}
492 
493 		*readval = ret;
494 		ret = 0;
495 	} else {
496 		ret = ad5758_spi_reg_write(st, reg, writeval);
497 	}
498 	mutex_unlock(&st->lock);
499 
500 	return ret;
501 }
502 
503 static int ad5758_read_raw(struct iio_dev *indio_dev,
504 			   struct iio_chan_spec const *chan,
505 			   int *val, int *val2, long info)
506 {
507 	struct ad5758_state *st = iio_priv(indio_dev);
508 	int max, min, ret;
509 
510 	switch (info) {
511 	case IIO_CHAN_INFO_RAW:
512 		mutex_lock(&st->lock);
513 		ret = ad5758_spi_reg_read(st, AD5758_DAC_INPUT);
514 		mutex_unlock(&st->lock);
515 		if (ret < 0)
516 			return ret;
517 
518 		*val = ret;
519 		return IIO_VAL_INT;
520 	case IIO_CHAN_INFO_SCALE:
521 		min = st->out_range.min;
522 		max = st->out_range.max;
523 		*val = (max - min) / 1000;
524 		*val2 = 16;
525 		return IIO_VAL_FRACTIONAL_LOG2;
526 	case IIO_CHAN_INFO_OFFSET:
527 		min = st->out_range.min;
528 		max = st->out_range.max;
529 		*val = ((min * (1 << 16)) / (max - min)) / 1000;
530 		return IIO_VAL_INT;
531 	default:
532 		return -EINVAL;
533 	}
534 }
535 
536 static int ad5758_write_raw(struct iio_dev *indio_dev,
537 			    struct iio_chan_spec const *chan,
538 			    int val, int val2, long info)
539 {
540 	struct ad5758_state *st = iio_priv(indio_dev);
541 	int ret;
542 
543 	switch (info) {
544 	case IIO_CHAN_INFO_RAW:
545 		mutex_lock(&st->lock);
546 		ret = ad5758_spi_reg_write(st, AD5758_DAC_INPUT, val);
547 		mutex_unlock(&st->lock);
548 		return ret;
549 	default:
550 		return -EINVAL;
551 	}
552 }
553 
554 static ssize_t ad5758_read_powerdown(struct iio_dev *indio_dev,
555 				     uintptr_t priv,
556 				     const struct iio_chan_spec *chan,
557 				     char *buf)
558 {
559 	struct ad5758_state *st = iio_priv(indio_dev);
560 
561 	return sprintf(buf, "%d\n", st->pwr_down);
562 }
563 
564 static ssize_t ad5758_write_powerdown(struct iio_dev *indio_dev,
565 				      uintptr_t priv,
566 				      struct iio_chan_spec const *chan,
567 				      const char *buf, size_t len)
568 {
569 	struct ad5758_state *st = iio_priv(indio_dev);
570 	bool pwr_down;
571 	unsigned int dcdc_config1_mode, dc_dc_mode, dac_config_mode, val;
572 	unsigned long int dcdc_config1_msk, dac_config_msk;
573 	int ret;
574 
575 	ret = kstrtobool(buf, &pwr_down);
576 	if (ret)
577 		return ret;
578 
579 	mutex_lock(&st->lock);
580 	if (pwr_down) {
581 		dc_dc_mode = AD5758_DCDC_MODE_POWER_OFF;
582 		val = 0;
583 	} else {
584 		dc_dc_mode = st->dc_dc_mode;
585 		val = 1;
586 	}
587 
588 	dcdc_config1_mode = AD5758_DCDC_CONFIG1_DCDC_MODE_MODE(dc_dc_mode) |
589 			    AD5758_DCDC_CONFIG1_PROT_SW_EN_MODE(val);
590 	dcdc_config1_msk = AD5758_DCDC_CONFIG1_DCDC_MODE_MSK |
591 			   AD5758_DCDC_CONFIG1_PROT_SW_EN_MSK;
592 
593 	ret = ad5758_spi_write_mask(st, AD5758_DCDC_CONFIG1,
594 				    dcdc_config1_msk,
595 				    dcdc_config1_mode);
596 	if (ret < 0)
597 		goto err_unlock;
598 
599 	dac_config_mode = AD5758_DAC_CONFIG_OUT_EN_MODE(val) |
600 			  AD5758_DAC_CONFIG_INT_EN_MODE(val);
601 	dac_config_msk = AD5758_DAC_CONFIG_OUT_EN_MSK |
602 			 AD5758_DAC_CONFIG_INT_EN_MSK;
603 
604 	ret = ad5758_spi_write_mask(st, AD5758_DAC_CONFIG,
605 				    dac_config_msk,
606 				    dac_config_mode);
607 	if (ret < 0)
608 		goto err_unlock;
609 
610 	st->pwr_down = pwr_down;
611 
612 err_unlock:
613 	mutex_unlock(&st->lock);
614 
615 	return ret ? ret : len;
616 }
617 
618 static const struct iio_info ad5758_info = {
619 	.read_raw = ad5758_read_raw,
620 	.write_raw = ad5758_write_raw,
621 	.debugfs_reg_access = &ad5758_reg_access,
622 };
623 
624 static const struct iio_chan_spec_ext_info ad5758_ext_info[] = {
625 	{
626 		.name = "powerdown",
627 		.read = ad5758_read_powerdown,
628 		.write = ad5758_write_powerdown,
629 		.shared = IIO_SHARED_BY_TYPE,
630 	},
631 	{ }
632 };
633 
634 #define AD5758_DAC_CHAN(_chan_type) {				\
635 	.type = (_chan_type),					\
636 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_RAW) |	\
637 		BIT(IIO_CHAN_INFO_SCALE) |			\
638 		BIT(IIO_CHAN_INFO_OFFSET),			\
639 	.indexed = 1,						\
640 	.output = 1,						\
641 	.ext_info = ad5758_ext_info,				\
642 }
643 
644 static const struct iio_chan_spec ad5758_voltage_ch[] = {
645 	AD5758_DAC_CHAN(IIO_VOLTAGE)
646 };
647 
648 static const struct iio_chan_spec ad5758_current_ch[] = {
649 	AD5758_DAC_CHAN(IIO_CURRENT)
650 };
651 
652 static bool ad5758_is_valid_mode(enum ad5758_dc_dc_mode mode)
653 {
654 	switch (mode) {
655 	case AD5758_DCDC_MODE_DPC_CURRENT:
656 	case AD5758_DCDC_MODE_DPC_VOLTAGE:
657 	case AD5758_DCDC_MODE_PPC_CURRENT:
658 		return true;
659 	default:
660 		return false;
661 	}
662 }
663 
664 static int ad5758_crc_disable(struct ad5758_state *st)
665 {
666 	unsigned int mask;
667 
668 	mask = (AD5758_WR_FLAG_MSK(AD5758_DIGITAL_DIAG_CONFIG) << 24) | 0x5C3A;
669 	st->d32[0] = cpu_to_be32(mask);
670 
671 	return spi_write(st->spi, &st->d32[0], 4);
672 }
673 
674 static int ad5758_find_out_range(struct ad5758_state *st,
675 				 const struct ad5758_range *range,
676 				 unsigned int size,
677 				 int min, int max)
678 {
679 	int i;
680 
681 	for (i = 0; i < size; i++) {
682 		if ((min == range[i].min) && (max == range[i].max)) {
683 			st->out_range.reg = range[i].reg;
684 			st->out_range.min = range[i].min;
685 			st->out_range.max = range[i].max;
686 
687 			return 0;
688 		}
689 	}
690 
691 	return -EINVAL;
692 }
693 
694 static int ad5758_parse_dt(struct ad5758_state *st)
695 {
696 	unsigned int tmp, tmparray[2], size;
697 	const struct ad5758_range *range;
698 	int *index, ret;
699 
700 	st->dc_dc_ilim = 0;
701 	ret = device_property_read_u32(&st->spi->dev,
702 				       "adi,dc-dc-ilim-microamp", &tmp);
703 	if (ret) {
704 		dev_dbg(&st->spi->dev,
705 			"Missing \"dc-dc-ilim-microamp\" property\n");
706 	} else {
707 		index = bsearch(&tmp, ad5758_dc_dc_ilim,
708 				ARRAY_SIZE(ad5758_dc_dc_ilim),
709 				sizeof(int), cmpfunc);
710 		if (!index)
711 			dev_dbg(&st->spi->dev, "dc-dc-ilim out of range\n");
712 		else
713 			st->dc_dc_ilim = index - ad5758_dc_dc_ilim;
714 	}
715 
716 	ret = device_property_read_u32(&st->spi->dev, "adi,dc-dc-mode",
717 				       &st->dc_dc_mode);
718 	if (ret) {
719 		dev_err(&st->spi->dev, "Missing \"dc-dc-mode\" property\n");
720 		return ret;
721 	}
722 
723 	if (!ad5758_is_valid_mode(st->dc_dc_mode))
724 		return -EINVAL;
725 
726 	if (st->dc_dc_mode == AD5758_DCDC_MODE_DPC_VOLTAGE) {
727 		ret = device_property_read_u32_array(&st->spi->dev,
728 						     "adi,range-microvolt",
729 						     tmparray, 2);
730 		if (ret) {
731 			dev_err(&st->spi->dev,
732 				"Missing \"range-microvolt\" property\n");
733 			return ret;
734 		}
735 		range = ad5758_voltage_range;
736 		size = ARRAY_SIZE(ad5758_voltage_range);
737 	} else {
738 		ret = device_property_read_u32_array(&st->spi->dev,
739 						     "adi,range-microamp",
740 						     tmparray, 2);
741 		if (ret) {
742 			dev_err(&st->spi->dev,
743 				"Missing \"range-microamp\" property\n");
744 			return ret;
745 		}
746 		range = ad5758_current_range;
747 		size = ARRAY_SIZE(ad5758_current_range);
748 	}
749 
750 	ret = ad5758_find_out_range(st, range, size, tmparray[0], tmparray[1]);
751 	if (ret) {
752 		dev_err(&st->spi->dev, "range invalid\n");
753 		return ret;
754 	}
755 
756 	ret = device_property_read_u32(&st->spi->dev, "adi,slew-time-us", &tmp);
757 	if (ret) {
758 		dev_dbg(&st->spi->dev, "Missing \"slew-time-us\" property\n");
759 		st->slew_time = 0;
760 	} else {
761 		st->slew_time = tmp;
762 	}
763 
764 	return 0;
765 }
766 
767 static int ad5758_init(struct ad5758_state *st)
768 {
769 	int regval, ret;
770 
771 	/* Disable CRC checks */
772 	ret = ad5758_crc_disable(st);
773 	if (ret < 0)
774 		return ret;
775 
776 	/* Perform a software reset */
777 	ret = ad5758_soft_reset(st);
778 	if (ret < 0)
779 		return ret;
780 
781 	/* Disable CRC checks */
782 	ret = ad5758_crc_disable(st);
783 	if (ret < 0)
784 		return ret;
785 
786 	/* Perform a calibration memory refresh */
787 	ret = ad5758_calib_mem_refresh(st);
788 	if (ret < 0)
789 		return ret;
790 
791 	regval = ad5758_spi_reg_read(st, AD5758_DIGITAL_DIAG_RESULTS);
792 	if (regval < 0)
793 		return regval;
794 
795 	/* Clear all the error flags */
796 	ret = ad5758_spi_reg_write(st, AD5758_DIGITAL_DIAG_RESULTS, regval);
797 	if (ret < 0)
798 		return ret;
799 
800 	/* Set the dc-to-dc current limit */
801 	ret = ad5758_set_dc_dc_ilim(st, st->dc_dc_ilim);
802 	if (ret < 0)
803 		return ret;
804 
805 	/* Configure the dc-to-dc controller mode */
806 	ret = ad5758_set_dc_dc_conv_mode(st, st->dc_dc_mode);
807 	if (ret < 0)
808 		return ret;
809 
810 	/* Configure the output range */
811 	ret = ad5758_set_out_range(st, st->out_range.reg);
812 	if (ret < 0)
813 		return ret;
814 
815 	/* Enable Slew Rate Control, set the slew rate clock and step */
816 	if (st->slew_time) {
817 		ret = ad5758_slew_rate_config(st);
818 		if (ret < 0)
819 			return ret;
820 	}
821 
822 	/* Enable the VIOUT fault protection switch (FPS is closed) */
823 	ret = ad5758_fault_prot_switch_en(st, 1);
824 	if (ret < 0)
825 		return ret;
826 
827 	/* Power up the DAC and internal (INT) amplifiers */
828 	ret = ad5758_internal_buffers_en(st, 1);
829 	if (ret < 0)
830 		return ret;
831 
832 	/* Enable VIOUT */
833 	return ad5758_spi_write_mask(st, AD5758_DAC_CONFIG,
834 				     AD5758_DAC_CONFIG_OUT_EN_MSK,
835 				     AD5758_DAC_CONFIG_OUT_EN_MODE(1));
836 }
837 
838 static int ad5758_probe(struct spi_device *spi)
839 {
840 	struct ad5758_state *st;
841 	struct iio_dev *indio_dev;
842 	int ret;
843 
844 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
845 	if (!indio_dev)
846 		return -ENOMEM;
847 
848 	st = iio_priv(indio_dev);
849 	spi_set_drvdata(spi, indio_dev);
850 
851 	st->spi = spi;
852 
853 	mutex_init(&st->lock);
854 
855 	indio_dev->dev.parent = &spi->dev;
856 	indio_dev->name = spi_get_device_id(spi)->name;
857 	indio_dev->info = &ad5758_info;
858 	indio_dev->modes = INDIO_DIRECT_MODE;
859 	indio_dev->num_channels = 1;
860 
861 	ret = ad5758_parse_dt(st);
862 	if (ret < 0)
863 		return ret;
864 
865 	if (st->dc_dc_mode == AD5758_DCDC_MODE_DPC_VOLTAGE)
866 		indio_dev->channels = ad5758_voltage_ch;
867 	else
868 		indio_dev->channels = ad5758_current_ch;
869 
870 	ret = ad5758_init(st);
871 	if (ret < 0) {
872 		dev_err(&spi->dev, "AD5758 init failed\n");
873 		return ret;
874 	}
875 
876 	return devm_iio_device_register(&st->spi->dev, indio_dev);
877 }
878 
879 static const struct spi_device_id ad5758_id[] = {
880 	{ "ad5758", 0 },
881 	{}
882 };
883 MODULE_DEVICE_TABLE(spi, ad5758_id);
884 
885 static struct spi_driver ad5758_driver = {
886 	.driver = {
887 		.name = KBUILD_MODNAME,
888 	},
889 	.probe = ad5758_probe,
890 	.id_table = ad5758_id,
891 };
892 
893 module_spi_driver(ad5758_driver);
894 
895 MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
896 MODULE_DESCRIPTION("Analog Devices AD5758 DAC");
897 MODULE_LICENSE("GPL v2");
898