xref: /linux/drivers/iio/dac/ad5758.c (revision b8d312aa075f33282565467662c4628dae0a2aff)
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/of.h>
15 #include <linux/of_device.h>
16 #include <linux/spi/spi.h>
17 #include <linux/gpio/consumer.h>
18 
19 #include <linux/iio/iio.h>
20 #include <linux/iio/sysfs.h>
21 
22 /* AD5758 registers definition */
23 #define AD5758_NOP				0x00
24 #define AD5758_DAC_INPUT			0x01
25 #define AD5758_DAC_OUTPUT			0x02
26 #define AD5758_CLEAR_CODE			0x03
27 #define AD5758_USER_GAIN			0x04
28 #define AD5758_USER_OFFSET			0x05
29 #define AD5758_DAC_CONFIG			0x06
30 #define AD5758_SW_LDAC				0x07
31 #define AD5758_KEY				0x08
32 #define AD5758_GP_CONFIG1			0x09
33 #define AD5758_GP_CONFIG2			0x0A
34 #define AD5758_DCDC_CONFIG1			0x0B
35 #define AD5758_DCDC_CONFIG2			0x0C
36 #define AD5758_WDT_CONFIG			0x0F
37 #define AD5758_DIGITAL_DIAG_CONFIG		0x10
38 #define AD5758_ADC_CONFIG			0x11
39 #define AD5758_FAULT_PIN_CONFIG			0x12
40 #define AD5758_TWO_STAGE_READBACK_SELECT	0x13
41 #define AD5758_DIGITAL_DIAG_RESULTS		0x14
42 #define AD5758_ANALOG_DIAG_RESULTS		0x15
43 #define AD5758_STATUS				0x16
44 #define AD5758_CHIP_ID				0x17
45 #define AD5758_FREQ_MONITOR			0x18
46 #define AD5758_DEVICE_ID_0			0x19
47 #define AD5758_DEVICE_ID_1			0x1A
48 #define AD5758_DEVICE_ID_2			0x1B
49 #define AD5758_DEVICE_ID_3			0x1C
50 
51 /* AD5758_DAC_CONFIG */
52 #define AD5758_DAC_CONFIG_RANGE_MSK		GENMASK(3, 0)
53 #define AD5758_DAC_CONFIG_RANGE_MODE(x)		(((x) & 0xF) << 0)
54 #define AD5758_DAC_CONFIG_INT_EN_MSK		BIT(5)
55 #define AD5758_DAC_CONFIG_INT_EN_MODE(x)	(((x) & 0x1) << 5)
56 #define AD5758_DAC_CONFIG_OUT_EN_MSK		BIT(6)
57 #define AD5758_DAC_CONFIG_OUT_EN_MODE(x)	(((x) & 0x1) << 6)
58 #define AD5758_DAC_CONFIG_SR_EN_MSK		BIT(8)
59 #define AD5758_DAC_CONFIG_SR_EN_MODE(x)		(((x) & 0x1) << 8)
60 #define AD5758_DAC_CONFIG_SR_CLOCK_MSK		GENMASK(12, 9)
61 #define AD5758_DAC_CONFIG_SR_CLOCK_MODE(x)	(((x) & 0xF) << 9)
62 #define AD5758_DAC_CONFIG_SR_STEP_MSK		GENMASK(15, 13)
63 #define AD5758_DAC_CONFIG_SR_STEP_MODE(x)	(((x) & 0x7) << 13)
64 
65 /* AD5758_KEY */
66 #define AD5758_KEY_CODE_RESET_1			0x15FA
67 #define AD5758_KEY_CODE_RESET_2			0xAF51
68 #define AD5758_KEY_CODE_SINGLE_ADC_CONV		0x1ADC
69 #define AD5758_KEY_CODE_RESET_WDT		0x0D06
70 #define AD5758_KEY_CODE_CALIB_MEM_REFRESH	0xFCBA
71 
72 /* AD5758_DCDC_CONFIG1 */
73 #define AD5758_DCDC_CONFIG1_DCDC_VPROG_MSK	GENMASK(4, 0)
74 #define AD5758_DCDC_CONFIG1_DCDC_VPROG_MODE(x)	(((x) & 0x1F) << 0)
75 #define AD5758_DCDC_CONFIG1_DCDC_MODE_MSK	GENMASK(6, 5)
76 #define AD5758_DCDC_CONFIG1_DCDC_MODE_MODE(x)	(((x) & 0x3) << 5)
77 
78 /* AD5758_DCDC_CONFIG2 */
79 #define AD5758_DCDC_CONFIG2_ILIMIT_MSK		GENMASK(3, 1)
80 #define AD5758_DCDC_CONFIG2_ILIMIT_MODE(x)	(((x) & 0x7) << 1)
81 #define AD5758_DCDC_CONFIG2_INTR_SAT_3WI_MSK	BIT(11)
82 #define AD5758_DCDC_CONFIG2_BUSY_3WI_MSK	BIT(12)
83 
84 /* AD5758_DIGITAL_DIAG_RESULTS */
85 #define AD5758_CAL_MEM_UNREFRESHED_MSK		BIT(15)
86 
87 /* AD5758_ADC_CONFIG */
88 #define AD5758_ADC_CONFIG_PPC_BUF_EN(x)		(((x) & 0x1) << 11)
89 #define AD5758_ADC_CONFIG_PPC_BUF_MSK		BIT(11)
90 
91 #define AD5758_WR_FLAG_MSK(x)		(0x80 | ((x) & 0x1F))
92 
93 #define AD5758_FULL_SCALE_MICRO	65535000000ULL
94 
95 /**
96  * struct ad5758_state - driver instance specific data
97  * @spi:	spi_device
98  * @lock:	mutex lock
99  * @out_range:	struct which stores the output range
100  * @dc_dc_mode:	variable which stores the mode of operation
101  * @dc_dc_ilim:	variable which stores the dc-to-dc converter current limit
102  * @slew_time:	variable which stores the target slew time
103  * @pwr_down:	variable which contains whether a channel is powered down or not
104  * @data:	spi transfer buffers
105  */
106 
107 struct ad5758_range {
108 	int reg;
109 	int min;
110 	int max;
111 };
112 
113 struct ad5758_state {
114 	struct spi_device *spi;
115 	struct mutex lock;
116 	struct gpio_desc *gpio_reset;
117 	struct ad5758_range out_range;
118 	unsigned int dc_dc_mode;
119 	unsigned int dc_dc_ilim;
120 	unsigned int slew_time;
121 	bool pwr_down;
122 	__be32 d32[3];
123 };
124 
125 /**
126  * Output ranges corresponding to bits [3:0] from DAC_CONFIG register
127  * 0000: 0 V to 5 V voltage range
128  * 0001: 0 V to 10 V voltage range
129  * 0010: ±5 V voltage range
130  * 0011: ±10 V voltage range
131  * 1000: 0 mA to 20 mA current range
132  * 1001: 0 mA to 24 mA current range
133  * 1010: 4 mA to 20 mA current range
134  * 1011: ±20 mA current range
135  * 1100: ±24 mA current range
136  * 1101: -1 mA to +22 mA current range
137  */
138 enum ad5758_output_range {
139 	AD5758_RANGE_0V_5V,
140 	AD5758_RANGE_0V_10V,
141 	AD5758_RANGE_PLUSMINUS_5V,
142 	AD5758_RANGE_PLUSMINUS_10V,
143 	AD5758_RANGE_0mA_20mA = 8,
144 	AD5758_RANGE_0mA_24mA,
145 	AD5758_RANGE_4mA_24mA,
146 	AD5758_RANGE_PLUSMINUS_20mA,
147 	AD5758_RANGE_PLUSMINUS_24mA,
148 	AD5758_RANGE_MINUS_1mA_PLUS_22mA,
149 };
150 
151 enum ad5758_dc_dc_mode {
152 	AD5758_DCDC_MODE_POWER_OFF,
153 	AD5758_DCDC_MODE_DPC_CURRENT,
154 	AD5758_DCDC_MODE_DPC_VOLTAGE,
155 	AD5758_DCDC_MODE_PPC_CURRENT,
156 };
157 
158 static const struct ad5758_range ad5758_voltage_range[] = {
159 	{ AD5758_RANGE_0V_5V, 0, 5000000 },
160 	{ AD5758_RANGE_0V_10V, 0, 10000000 },
161 	{ AD5758_RANGE_PLUSMINUS_5V, -5000000, 5000000 },
162 	{ AD5758_RANGE_PLUSMINUS_10V, -10000000, 10000000 }
163 };
164 
165 static const struct ad5758_range ad5758_current_range[] = {
166 	{ AD5758_RANGE_0mA_20mA, 0, 20000},
167 	{ AD5758_RANGE_0mA_24mA, 0, 24000 },
168 	{ AD5758_RANGE_4mA_24mA, 4, 24000 },
169 	{ AD5758_RANGE_PLUSMINUS_20mA, -20000, 20000 },
170 	{ AD5758_RANGE_PLUSMINUS_24mA, -24000, 24000 },
171 	{ AD5758_RANGE_MINUS_1mA_PLUS_22mA, -1000, 22000 },
172 };
173 
174 static const int ad5758_sr_clk[16] = {
175 	240000, 200000, 150000, 128000, 64000, 32000, 16000, 8000, 4000, 2000,
176 	1000, 512, 256, 128, 64, 16
177 };
178 
179 static const int ad5758_sr_step[8] = {
180 	4, 12, 64, 120, 256, 500, 1820, 2048
181 };
182 
183 static const int ad5758_dc_dc_ilim[6] = {
184 	150000, 200000, 250000, 300000, 350000, 400000
185 };
186 
187 static int ad5758_spi_reg_read(struct ad5758_state *st, unsigned int addr)
188 {
189 	struct spi_transfer t[] = {
190 		{
191 			.tx_buf = &st->d32[0],
192 			.len = 4,
193 			.cs_change = 1,
194 		}, {
195 			.tx_buf = &st->d32[1],
196 			.rx_buf = &st->d32[2],
197 			.len = 4,
198 		},
199 	};
200 	int ret;
201 
202 	st->d32[0] = cpu_to_be32(
203 		(AD5758_WR_FLAG_MSK(AD5758_TWO_STAGE_READBACK_SELECT) << 24) |
204 		(addr << 8));
205 	st->d32[1] = cpu_to_be32(AD5758_WR_FLAG_MSK(AD5758_NOP) << 24);
206 
207 	ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
208 	if (ret < 0)
209 		return ret;
210 
211 	return (be32_to_cpu(st->d32[2]) >> 8) & 0xFFFF;
212 }
213 
214 static int ad5758_spi_reg_write(struct ad5758_state *st,
215 				unsigned int addr,
216 				unsigned int val)
217 {
218 	st->d32[0] = cpu_to_be32((AD5758_WR_FLAG_MSK(addr) << 24) |
219 				 ((val & 0xFFFF) << 8));
220 
221 	return spi_write(st->spi, &st->d32[0], sizeof(st->d32[0]));
222 }
223 
224 static int ad5758_spi_write_mask(struct ad5758_state *st,
225 				 unsigned int addr,
226 				 unsigned long int mask,
227 				 unsigned int val)
228 {
229 	int regval;
230 
231 	regval = ad5758_spi_reg_read(st, addr);
232 	if (regval < 0)
233 		return regval;
234 
235 	regval &= ~mask;
236 	regval |= val;
237 
238 	return ad5758_spi_reg_write(st, addr, regval);
239 }
240 
241 static int cmpfunc(const void *a, const void *b)
242 {
243 	return *(int *)a - *(int *)b;
244 }
245 
246 static int ad5758_find_closest_match(const int *array,
247 				     unsigned int size, int val)
248 {
249 	int i;
250 
251 	for (i = 0; i < size; i++) {
252 		if (val <= array[i])
253 			return i;
254 	}
255 
256 	return size - 1;
257 }
258 
259 static int ad5758_wait_for_task_complete(struct ad5758_state *st,
260 					 unsigned int reg,
261 					 unsigned int mask)
262 {
263 	unsigned int timeout;
264 	int ret;
265 
266 	timeout = 10;
267 	do {
268 		ret = ad5758_spi_reg_read(st, reg);
269 		if (ret < 0)
270 			return ret;
271 
272 		if (!(ret & mask))
273 			return 0;
274 
275 		usleep_range(100, 1000);
276 	} while (--timeout);
277 
278 	dev_err(&st->spi->dev,
279 		"Error reading bit 0x%x in 0x%x register\n", mask, reg);
280 
281 	return -EIO;
282 }
283 
284 static int ad5758_calib_mem_refresh(struct ad5758_state *st)
285 {
286 	int ret;
287 
288 	ret = ad5758_spi_reg_write(st, AD5758_KEY,
289 				   AD5758_KEY_CODE_CALIB_MEM_REFRESH);
290 	if (ret < 0) {
291 		dev_err(&st->spi->dev,
292 			"Failed to initiate a calibration memory refresh\n");
293 		return ret;
294 	}
295 
296 	/* Wait to allow time for the internal calibrations to complete */
297 	return ad5758_wait_for_task_complete(st, AD5758_DIGITAL_DIAG_RESULTS,
298 					     AD5758_CAL_MEM_UNREFRESHED_MSK);
299 }
300 
301 static int ad5758_soft_reset(struct ad5758_state *st)
302 {
303 	int ret;
304 
305 	ret = ad5758_spi_reg_write(st, AD5758_KEY, AD5758_KEY_CODE_RESET_1);
306 	if (ret < 0)
307 		return ret;
308 
309 	ret = ad5758_spi_reg_write(st, AD5758_KEY, AD5758_KEY_CODE_RESET_2);
310 
311 	/* Perform a software reset and wait at least 100us */
312 	usleep_range(100, 1000);
313 
314 	return ret;
315 }
316 
317 static int ad5758_set_dc_dc_conv_mode(struct ad5758_state *st,
318 				      enum ad5758_dc_dc_mode mode)
319 {
320 	int ret;
321 
322 	/*
323 	 * The ENABLE_PPC_BUFFERS bit must be set prior to enabling PPC current
324 	 * mode.
325 	 */
326 	if (mode == AD5758_DCDC_MODE_PPC_CURRENT) {
327 		ret  = ad5758_spi_write_mask(st, AD5758_ADC_CONFIG,
328 				    AD5758_ADC_CONFIG_PPC_BUF_MSK,
329 				    AD5758_ADC_CONFIG_PPC_BUF_EN(1));
330 		if (ret < 0)
331 			return ret;
332 	}
333 
334 	ret = ad5758_spi_write_mask(st, AD5758_DCDC_CONFIG1,
335 				    AD5758_DCDC_CONFIG1_DCDC_MODE_MSK,
336 				    AD5758_DCDC_CONFIG1_DCDC_MODE_MODE(mode));
337 	if (ret < 0)
338 		return ret;
339 
340 	/*
341 	 * Poll the BUSY_3WI bit in the DCDC_CONFIG2 register until it is 0.
342 	 * This allows the 3-wire interface communication to complete.
343 	 */
344 	ret = ad5758_wait_for_task_complete(st, AD5758_DCDC_CONFIG2,
345 					    AD5758_DCDC_CONFIG2_BUSY_3WI_MSK);
346 	if (ret < 0)
347 		return ret;
348 
349 	st->dc_dc_mode = mode;
350 
351 	return ret;
352 }
353 
354 static int ad5758_set_dc_dc_ilim(struct ad5758_state *st, unsigned int ilim)
355 {
356 	int ret;
357 
358 	ret = ad5758_spi_write_mask(st, AD5758_DCDC_CONFIG2,
359 				    AD5758_DCDC_CONFIG2_ILIMIT_MSK,
360 				    AD5758_DCDC_CONFIG2_ILIMIT_MODE(ilim));
361 	if (ret < 0)
362 		return ret;
363 	/*
364 	 * Poll the BUSY_3WI bit in the DCDC_CONFIG2 register until it is 0.
365 	 * This allows the 3-wire interface communication to complete.
366 	 */
367 	return ad5758_wait_for_task_complete(st, AD5758_DCDC_CONFIG2,
368 					     AD5758_DCDC_CONFIG2_BUSY_3WI_MSK);
369 }
370 
371 static int ad5758_slew_rate_set(struct ad5758_state *st,
372 				unsigned int sr_clk_idx,
373 				unsigned int sr_step_idx)
374 {
375 	unsigned int mode;
376 	unsigned long int mask;
377 	int ret;
378 
379 	mask = AD5758_DAC_CONFIG_SR_EN_MSK |
380 	       AD5758_DAC_CONFIG_SR_CLOCK_MSK |
381 	       AD5758_DAC_CONFIG_SR_STEP_MSK;
382 	mode = AD5758_DAC_CONFIG_SR_EN_MODE(1) |
383 	       AD5758_DAC_CONFIG_SR_STEP_MODE(sr_step_idx) |
384 	       AD5758_DAC_CONFIG_SR_CLOCK_MODE(sr_clk_idx);
385 
386 	ret = ad5758_spi_write_mask(st, AD5758_DAC_CONFIG, mask, mode);
387 	if (ret < 0)
388 		return ret;
389 
390 	/* Wait to allow time for the internal calibrations to complete */
391 	return ad5758_wait_for_task_complete(st, AD5758_DIGITAL_DIAG_RESULTS,
392 					     AD5758_CAL_MEM_UNREFRESHED_MSK);
393 }
394 
395 static int ad5758_slew_rate_config(struct ad5758_state *st)
396 {
397 	unsigned int sr_clk_idx, sr_step_idx;
398 	int i, res;
399 	s64 diff_new, diff_old;
400 	u64 sr_step, calc_slew_time;
401 
402 	sr_clk_idx = 0;
403 	sr_step_idx = 0;
404 	diff_old = S64_MAX;
405 	/*
406 	 * The slew time can be determined by using the formula:
407 	 * Slew Time = (Full Scale Out / (Step Size x Update Clk Freq))
408 	 * where Slew time is expressed in microseconds
409 	 * Given the desired slew time, the following algorithm determines the
410 	 * best match for the step size and the update clock frequency.
411 	 */
412 	for (i = 0; i < ARRAY_SIZE(ad5758_sr_clk); i++) {
413 		/*
414 		 * Go through each valid update clock freq and determine a raw
415 		 * value for the step size by using the formula:
416 		 * Step Size = Full Scale Out / (Update Clk Freq * Slew Time)
417 		 */
418 		sr_step = AD5758_FULL_SCALE_MICRO;
419 		do_div(sr_step, ad5758_sr_clk[i]);
420 		do_div(sr_step, st->slew_time);
421 		/*
422 		 * After a raw value for step size was determined, find the
423 		 * closest valid match
424 		 */
425 		res = ad5758_find_closest_match(ad5758_sr_step,
426 						ARRAY_SIZE(ad5758_sr_step),
427 						sr_step);
428 		/* Calculate the slew time */
429 		calc_slew_time = AD5758_FULL_SCALE_MICRO;
430 		do_div(calc_slew_time, ad5758_sr_step[res]);
431 		do_div(calc_slew_time, ad5758_sr_clk[i]);
432 		/*
433 		 * Determine with how many microseconds the calculated slew time
434 		 * is different from the desired slew time and store the diff
435 		 * for the next iteration
436 		 */
437 		diff_new = abs(st->slew_time - calc_slew_time);
438 		if (diff_new < diff_old) {
439 			diff_old = diff_new;
440 			sr_clk_idx = i;
441 			sr_step_idx = res;
442 		}
443 	}
444 
445 	return ad5758_slew_rate_set(st, sr_clk_idx, sr_step_idx);
446 }
447 
448 static int ad5758_set_out_range(struct ad5758_state *st, int range)
449 {
450 	int ret;
451 
452 	ret = ad5758_spi_write_mask(st, AD5758_DAC_CONFIG,
453 				    AD5758_DAC_CONFIG_RANGE_MSK,
454 				    AD5758_DAC_CONFIG_RANGE_MODE(range));
455 	if (ret < 0)
456 		return ret;
457 
458 	/* Wait to allow time for the internal calibrations to complete */
459 	return ad5758_wait_for_task_complete(st, AD5758_DIGITAL_DIAG_RESULTS,
460 					     AD5758_CAL_MEM_UNREFRESHED_MSK);
461 }
462 
463 static int ad5758_internal_buffers_en(struct ad5758_state *st, bool enable)
464 {
465 	int ret;
466 
467 	ret = ad5758_spi_write_mask(st, AD5758_DAC_CONFIG,
468 				    AD5758_DAC_CONFIG_INT_EN_MSK,
469 				    AD5758_DAC_CONFIG_INT_EN_MODE(enable));
470 	if (ret < 0)
471 		return ret;
472 
473 	/* Wait to allow time for the internal calibrations to complete */
474 	return ad5758_wait_for_task_complete(st, AD5758_DIGITAL_DIAG_RESULTS,
475 					     AD5758_CAL_MEM_UNREFRESHED_MSK);
476 }
477 
478 static int ad5758_reset(struct ad5758_state *st)
479 {
480 	if (st->gpio_reset) {
481 		gpiod_set_value(st->gpio_reset, 0);
482 		usleep_range(100, 1000);
483 		gpiod_set_value(st->gpio_reset, 1);
484 		usleep_range(100, 1000);
485 
486 		return 0;
487 	} else {
488 		/* Perform a software reset */
489 		return ad5758_soft_reset(st);
490 	}
491 }
492 
493 static int ad5758_reg_access(struct iio_dev *indio_dev,
494 			     unsigned int reg,
495 			     unsigned int writeval,
496 			     unsigned int *readval)
497 {
498 	struct ad5758_state *st = iio_priv(indio_dev);
499 	int ret;
500 
501 	mutex_lock(&st->lock);
502 	if (readval) {
503 		ret = ad5758_spi_reg_read(st, reg);
504 		if (ret < 0) {
505 			mutex_unlock(&st->lock);
506 			return ret;
507 		}
508 
509 		*readval = ret;
510 		ret = 0;
511 	} else {
512 		ret = ad5758_spi_reg_write(st, reg, writeval);
513 	}
514 	mutex_unlock(&st->lock);
515 
516 	return ret;
517 }
518 
519 static int ad5758_read_raw(struct iio_dev *indio_dev,
520 			   struct iio_chan_spec const *chan,
521 			   int *val, int *val2, long info)
522 {
523 	struct ad5758_state *st = iio_priv(indio_dev);
524 	int max, min, ret;
525 
526 	switch (info) {
527 	case IIO_CHAN_INFO_RAW:
528 		mutex_lock(&st->lock);
529 		ret = ad5758_spi_reg_read(st, AD5758_DAC_INPUT);
530 		mutex_unlock(&st->lock);
531 		if (ret < 0)
532 			return ret;
533 
534 		*val = ret;
535 		return IIO_VAL_INT;
536 	case IIO_CHAN_INFO_SCALE:
537 		min = st->out_range.min;
538 		max = st->out_range.max;
539 		*val = (max - min) / 1000;
540 		*val2 = 16;
541 		return IIO_VAL_FRACTIONAL_LOG2;
542 	case IIO_CHAN_INFO_OFFSET:
543 		min = st->out_range.min;
544 		max = st->out_range.max;
545 		*val = ((min * (1 << 16)) / (max - min)) / 1000;
546 		return IIO_VAL_INT;
547 	default:
548 		return -EINVAL;
549 	}
550 }
551 
552 static int ad5758_write_raw(struct iio_dev *indio_dev,
553 			    struct iio_chan_spec const *chan,
554 			    int val, int val2, long info)
555 {
556 	struct ad5758_state *st = iio_priv(indio_dev);
557 	int ret;
558 
559 	switch (info) {
560 	case IIO_CHAN_INFO_RAW:
561 		mutex_lock(&st->lock);
562 		ret = ad5758_spi_reg_write(st, AD5758_DAC_INPUT, val);
563 		mutex_unlock(&st->lock);
564 		return ret;
565 	default:
566 		return -EINVAL;
567 	}
568 }
569 
570 static ssize_t ad5758_read_powerdown(struct iio_dev *indio_dev,
571 				     uintptr_t priv,
572 				     const struct iio_chan_spec *chan,
573 				     char *buf)
574 {
575 	struct ad5758_state *st = iio_priv(indio_dev);
576 
577 	return sprintf(buf, "%d\n", st->pwr_down);
578 }
579 
580 static ssize_t ad5758_write_powerdown(struct iio_dev *indio_dev,
581 				      uintptr_t priv,
582 				      struct iio_chan_spec const *chan,
583 				      const char *buf, size_t len)
584 {
585 	struct ad5758_state *st = iio_priv(indio_dev);
586 	bool pwr_down;
587 	unsigned int dac_config_mode, val;
588 	unsigned long int dac_config_msk;
589 	int ret;
590 
591 	ret = kstrtobool(buf, &pwr_down);
592 	if (ret)
593 		return ret;
594 
595 	mutex_lock(&st->lock);
596 	if (pwr_down)
597 		val = 0;
598 	else
599 		val = 1;
600 
601 	dac_config_mode = AD5758_DAC_CONFIG_OUT_EN_MODE(val) |
602 			  AD5758_DAC_CONFIG_INT_EN_MODE(val);
603 	dac_config_msk = AD5758_DAC_CONFIG_OUT_EN_MSK |
604 			 AD5758_DAC_CONFIG_INT_EN_MSK;
605 
606 	ret = ad5758_spi_write_mask(st, AD5758_DAC_CONFIG,
607 				    dac_config_msk,
608 				    dac_config_mode);
609 	if (ret < 0)
610 		goto err_unlock;
611 
612 	st->pwr_down = pwr_down;
613 
614 err_unlock:
615 	mutex_unlock(&st->lock);
616 
617 	return ret ? ret : len;
618 }
619 
620 static const struct iio_info ad5758_info = {
621 	.read_raw = ad5758_read_raw,
622 	.write_raw = ad5758_write_raw,
623 	.debugfs_reg_access = &ad5758_reg_access,
624 };
625 
626 static const struct iio_chan_spec_ext_info ad5758_ext_info[] = {
627 	{
628 		.name = "powerdown",
629 		.read = ad5758_read_powerdown,
630 		.write = ad5758_write_powerdown,
631 		.shared = IIO_SHARED_BY_TYPE,
632 	},
633 	{ }
634 };
635 
636 #define AD5758_DAC_CHAN(_chan_type) {				\
637 	.type = (_chan_type),					\
638 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_RAW) |	\
639 		BIT(IIO_CHAN_INFO_SCALE) |			\
640 		BIT(IIO_CHAN_INFO_OFFSET),			\
641 	.indexed = 1,						\
642 	.output = 1,						\
643 	.ext_info = ad5758_ext_info,				\
644 }
645 
646 static const struct iio_chan_spec ad5758_voltage_ch[] = {
647 	AD5758_DAC_CHAN(IIO_VOLTAGE)
648 };
649 
650 static const struct iio_chan_spec ad5758_current_ch[] = {
651 	AD5758_DAC_CHAN(IIO_CURRENT)
652 };
653 
654 static bool ad5758_is_valid_mode(enum ad5758_dc_dc_mode mode)
655 {
656 	switch (mode) {
657 	case AD5758_DCDC_MODE_DPC_CURRENT:
658 	case AD5758_DCDC_MODE_DPC_VOLTAGE:
659 	case AD5758_DCDC_MODE_PPC_CURRENT:
660 		return true;
661 	default:
662 		return false;
663 	}
664 }
665 
666 static int ad5758_crc_disable(struct ad5758_state *st)
667 {
668 	unsigned int mask;
669 
670 	mask = (AD5758_WR_FLAG_MSK(AD5758_DIGITAL_DIAG_CONFIG) << 24) | 0x5C3A;
671 	st->d32[0] = cpu_to_be32(mask);
672 
673 	return spi_write(st->spi, &st->d32[0], 4);
674 }
675 
676 static int ad5758_find_out_range(struct ad5758_state *st,
677 				 const struct ad5758_range *range,
678 				 unsigned int size,
679 				 int min, int max)
680 {
681 	int i;
682 
683 	for (i = 0; i < size; i++) {
684 		if ((min == range[i].min) && (max == range[i].max)) {
685 			st->out_range.reg = range[i].reg;
686 			st->out_range.min = range[i].min;
687 			st->out_range.max = range[i].max;
688 
689 			return 0;
690 		}
691 	}
692 
693 	return -EINVAL;
694 }
695 
696 static int ad5758_parse_dt(struct ad5758_state *st)
697 {
698 	unsigned int tmp, tmparray[2], size;
699 	const struct ad5758_range *range;
700 	int *index, ret;
701 
702 	st->dc_dc_ilim = 0;
703 	ret = device_property_read_u32(&st->spi->dev,
704 				       "adi,dc-dc-ilim-microamp", &tmp);
705 	if (ret) {
706 		dev_dbg(&st->spi->dev,
707 			"Missing \"dc-dc-ilim-microamp\" property\n");
708 	} else {
709 		index = bsearch(&tmp, ad5758_dc_dc_ilim,
710 				ARRAY_SIZE(ad5758_dc_dc_ilim),
711 				sizeof(int), cmpfunc);
712 		if (!index)
713 			dev_dbg(&st->spi->dev, "dc-dc-ilim out of range\n");
714 		else
715 			st->dc_dc_ilim = index - ad5758_dc_dc_ilim;
716 	}
717 
718 	ret = device_property_read_u32(&st->spi->dev, "adi,dc-dc-mode",
719 				       &st->dc_dc_mode);
720 	if (ret) {
721 		dev_err(&st->spi->dev, "Missing \"dc-dc-mode\" property\n");
722 		return ret;
723 	}
724 
725 	if (!ad5758_is_valid_mode(st->dc_dc_mode))
726 		return -EINVAL;
727 
728 	if (st->dc_dc_mode == AD5758_DCDC_MODE_DPC_VOLTAGE) {
729 		ret = device_property_read_u32_array(&st->spi->dev,
730 						     "adi,range-microvolt",
731 						     tmparray, 2);
732 		if (ret) {
733 			dev_err(&st->spi->dev,
734 				"Missing \"range-microvolt\" property\n");
735 			return ret;
736 		}
737 		range = ad5758_voltage_range;
738 		size = ARRAY_SIZE(ad5758_voltage_range);
739 	} else {
740 		ret = device_property_read_u32_array(&st->spi->dev,
741 						     "adi,range-microamp",
742 						     tmparray, 2);
743 		if (ret) {
744 			dev_err(&st->spi->dev,
745 				"Missing \"range-microamp\" property\n");
746 			return ret;
747 		}
748 		range = ad5758_current_range;
749 		size = ARRAY_SIZE(ad5758_current_range);
750 	}
751 
752 	ret = ad5758_find_out_range(st, range, size, tmparray[0], tmparray[1]);
753 	if (ret) {
754 		dev_err(&st->spi->dev, "range invalid\n");
755 		return ret;
756 	}
757 
758 	ret = device_property_read_u32(&st->spi->dev, "adi,slew-time-us", &tmp);
759 	if (ret) {
760 		dev_dbg(&st->spi->dev, "Missing \"slew-time-us\" property\n");
761 		st->slew_time = 0;
762 	} else {
763 		st->slew_time = tmp;
764 	}
765 
766 	return 0;
767 }
768 
769 static int ad5758_init(struct ad5758_state *st)
770 {
771 	int regval, ret;
772 
773 	st->gpio_reset = devm_gpiod_get_optional(&st->spi->dev, "reset",
774 						 GPIOD_OUT_HIGH);
775 	if (IS_ERR(st->gpio_reset))
776 		return PTR_ERR(st->gpio_reset);
777 
778 	/* Disable CRC checks */
779 	ret = ad5758_crc_disable(st);
780 	if (ret < 0)
781 		return ret;
782 
783 	/* Perform a reset */
784 	ret = ad5758_reset(st);
785 	if (ret < 0)
786 		return ret;
787 
788 	/* Disable CRC checks */
789 	ret = ad5758_crc_disable(st);
790 	if (ret < 0)
791 		return ret;
792 
793 	/* Perform a calibration memory refresh */
794 	ret = ad5758_calib_mem_refresh(st);
795 	if (ret < 0)
796 		return ret;
797 
798 	regval = ad5758_spi_reg_read(st, AD5758_DIGITAL_DIAG_RESULTS);
799 	if (regval < 0)
800 		return regval;
801 
802 	/* Clear all the error flags */
803 	ret = ad5758_spi_reg_write(st, AD5758_DIGITAL_DIAG_RESULTS, regval);
804 	if (ret < 0)
805 		return ret;
806 
807 	/* Set the dc-to-dc current limit */
808 	ret = ad5758_set_dc_dc_ilim(st, st->dc_dc_ilim);
809 	if (ret < 0)
810 		return ret;
811 
812 	/* Configure the dc-to-dc controller mode */
813 	ret = ad5758_set_dc_dc_conv_mode(st, st->dc_dc_mode);
814 	if (ret < 0)
815 		return ret;
816 
817 	/* Configure the output range */
818 	ret = ad5758_set_out_range(st, st->out_range.reg);
819 	if (ret < 0)
820 		return ret;
821 
822 	/* Enable Slew Rate Control, set the slew rate clock and step */
823 	if (st->slew_time) {
824 		ret = ad5758_slew_rate_config(st);
825 		if (ret < 0)
826 			return ret;
827 	}
828 
829 	/* Power up the DAC and internal (INT) amplifiers */
830 	ret = ad5758_internal_buffers_en(st, 1);
831 	if (ret < 0)
832 		return ret;
833 
834 	/* Enable VIOUT */
835 	return ad5758_spi_write_mask(st, AD5758_DAC_CONFIG,
836 				     AD5758_DAC_CONFIG_OUT_EN_MSK,
837 				     AD5758_DAC_CONFIG_OUT_EN_MODE(1));
838 }
839 
840 static int ad5758_probe(struct spi_device *spi)
841 {
842 	struct ad5758_state *st;
843 	struct iio_dev *indio_dev;
844 	int ret;
845 
846 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
847 	if (!indio_dev)
848 		return -ENOMEM;
849 
850 	st = iio_priv(indio_dev);
851 	spi_set_drvdata(spi, indio_dev);
852 
853 	st->spi = spi;
854 
855 	mutex_init(&st->lock);
856 
857 	indio_dev->dev.parent = &spi->dev;
858 	indio_dev->name = spi_get_device_id(spi)->name;
859 	indio_dev->info = &ad5758_info;
860 	indio_dev->modes = INDIO_DIRECT_MODE;
861 	indio_dev->num_channels = 1;
862 
863 	ret = ad5758_parse_dt(st);
864 	if (ret < 0)
865 		return ret;
866 
867 	if (st->dc_dc_mode == AD5758_DCDC_MODE_DPC_VOLTAGE)
868 		indio_dev->channels = ad5758_voltage_ch;
869 	else
870 		indio_dev->channels = ad5758_current_ch;
871 
872 	ret = ad5758_init(st);
873 	if (ret < 0) {
874 		dev_err(&spi->dev, "AD5758 init failed\n");
875 		return ret;
876 	}
877 
878 	return devm_iio_device_register(&st->spi->dev, indio_dev);
879 }
880 
881 static const struct spi_device_id ad5758_id[] = {
882 	{ "ad5758", 0 },
883 	{}
884 };
885 MODULE_DEVICE_TABLE(spi, ad5758_id);
886 
887 static const struct of_device_id ad5758_of_match[] = {
888         { .compatible = "adi,ad5758" },
889         { },
890 };
891 MODULE_DEVICE_TABLE(of, ad5758_of_match);
892 
893 static struct spi_driver ad5758_driver = {
894 	.driver = {
895 		.name = KBUILD_MODNAME,
896 		.of_match_table = ad5758_of_match,
897 	},
898 	.probe = ad5758_probe,
899 	.id_table = ad5758_id,
900 };
901 
902 module_spi_driver(ad5758_driver);
903 
904 MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
905 MODULE_DESCRIPTION("Analog Devices AD5758 DAC");
906 MODULE_LICENSE("GPL v2");
907