xref: /openbmc/linux/drivers/iio/adc/ad7793.c (revision a06c488d)
1 /*
2  * AD7785/AD7792/AD7793/AD7794/AD7795 SPI ADC driver
3  *
4  * Copyright 2011-2012 Analog Devices Inc.
5  *
6  * Licensed under the GPL-2.
7  */
8 
9 #include <linux/interrupt.h>
10 #include <linux/device.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/sysfs.h>
14 #include <linux/spi/spi.h>
15 #include <linux/regulator/consumer.h>
16 #include <linux/err.h>
17 #include <linux/sched.h>
18 #include <linux/delay.h>
19 #include <linux/module.h>
20 
21 #include <linux/iio/iio.h>
22 #include <linux/iio/sysfs.h>
23 #include <linux/iio/buffer.h>
24 #include <linux/iio/trigger.h>
25 #include <linux/iio/trigger_consumer.h>
26 #include <linux/iio/triggered_buffer.h>
27 #include <linux/iio/adc/ad_sigma_delta.h>
28 #include <linux/platform_data/ad7793.h>
29 
30 /* Registers */
31 #define AD7793_REG_COMM		0 /* Communications Register (WO, 8-bit) */
32 #define AD7793_REG_STAT		0 /* Status Register	     (RO, 8-bit) */
33 #define AD7793_REG_MODE		1 /* Mode Register	     (RW, 16-bit */
34 #define AD7793_REG_CONF		2 /* Configuration Register  (RW, 16-bit) */
35 #define AD7793_REG_DATA		3 /* Data Register	     (RO, 16-/24-bit) */
36 #define AD7793_REG_ID		4 /* ID Register	     (RO, 8-bit) */
37 #define AD7793_REG_IO		5 /* IO Register	     (RO, 8-bit) */
38 #define AD7793_REG_OFFSET	6 /* Offset Register	     (RW, 16-bit
39 				   * (AD7792)/24-bit (AD7793)) */
40 #define AD7793_REG_FULLSALE	7 /* Full-Scale Register
41 				   * (RW, 16-bit (AD7792)/24-bit (AD7793)) */
42 
43 /* Communications Register Bit Designations (AD7793_REG_COMM) */
44 #define AD7793_COMM_WEN		(1 << 7) /* Write Enable */
45 #define AD7793_COMM_WRITE	(0 << 6) /* Write Operation */
46 #define AD7793_COMM_READ	(1 << 6) /* Read Operation */
47 #define AD7793_COMM_ADDR(x)	(((x) & 0x7) << 3) /* Register Address */
48 #define AD7793_COMM_CREAD	(1 << 2) /* Continuous Read of Data Register */
49 
50 /* Status Register Bit Designations (AD7793_REG_STAT) */
51 #define AD7793_STAT_RDY		(1 << 7) /* Ready */
52 #define AD7793_STAT_ERR		(1 << 6) /* Error (Overrange, Underrange) */
53 #define AD7793_STAT_CH3		(1 << 2) /* Channel 3 */
54 #define AD7793_STAT_CH2		(1 << 1) /* Channel 2 */
55 #define AD7793_STAT_CH1		(1 << 0) /* Channel 1 */
56 
57 /* Mode Register Bit Designations (AD7793_REG_MODE) */
58 #define AD7793_MODE_SEL(x)	(((x) & 0x7) << 13) /* Operation Mode Select */
59 #define AD7793_MODE_SEL_MASK	(0x7 << 13) /* Operation Mode Select mask */
60 #define AD7793_MODE_CLKSRC(x)	(((x) & 0x3) << 6) /* ADC Clock Source Select */
61 #define AD7793_MODE_RATE(x)	((x) & 0xF) /* Filter Update Rate Select */
62 
63 #define AD7793_MODE_CONT		0 /* Continuous Conversion Mode */
64 #define AD7793_MODE_SINGLE		1 /* Single Conversion Mode */
65 #define AD7793_MODE_IDLE		2 /* Idle Mode */
66 #define AD7793_MODE_PWRDN		3 /* Power-Down Mode */
67 #define AD7793_MODE_CAL_INT_ZERO	4 /* Internal Zero-Scale Calibration */
68 #define AD7793_MODE_CAL_INT_FULL	5 /* Internal Full-Scale Calibration */
69 #define AD7793_MODE_CAL_SYS_ZERO	6 /* System Zero-Scale Calibration */
70 #define AD7793_MODE_CAL_SYS_FULL	7 /* System Full-Scale Calibration */
71 
72 #define AD7793_CLK_INT		0 /* Internal 64 kHz Clock not
73 				   * available at the CLK pin */
74 #define AD7793_CLK_INT_CO	1 /* Internal 64 kHz Clock available
75 				   * at the CLK pin */
76 #define AD7793_CLK_EXT		2 /* External 64 kHz Clock */
77 #define AD7793_CLK_EXT_DIV2	3 /* External Clock divided by 2 */
78 
79 /* Configuration Register Bit Designations (AD7793_REG_CONF) */
80 #define AD7793_CONF_VBIAS(x)	(((x) & 0x3) << 14) /* Bias Voltage
81 						     * Generator Enable */
82 #define AD7793_CONF_BO_EN	(1 << 13) /* Burnout Current Enable */
83 #define AD7793_CONF_UNIPOLAR	(1 << 12) /* Unipolar/Bipolar Enable */
84 #define AD7793_CONF_BOOST	(1 << 11) /* Boost Enable */
85 #define AD7793_CONF_GAIN(x)	(((x) & 0x7) << 8) /* Gain Select */
86 #define AD7793_CONF_REFSEL(x)	((x) << 6) /* INT/EXT Reference Select */
87 #define AD7793_CONF_BUF		(1 << 4) /* Buffered Mode Enable */
88 #define AD7793_CONF_CHAN(x)	((x) & 0xf) /* Channel select */
89 #define AD7793_CONF_CHAN_MASK	0xf /* Channel select mask */
90 
91 #define AD7793_CH_AIN1P_AIN1M	0 /* AIN1(+) - AIN1(-) */
92 #define AD7793_CH_AIN2P_AIN2M	1 /* AIN2(+) - AIN2(-) */
93 #define AD7793_CH_AIN3P_AIN3M	2 /* AIN3(+) - AIN3(-) */
94 #define AD7793_CH_AIN1M_AIN1M	3 /* AIN1(-) - AIN1(-) */
95 #define AD7793_CH_TEMP		6 /* Temp Sensor */
96 #define AD7793_CH_AVDD_MONITOR	7 /* AVDD Monitor */
97 
98 #define AD7795_CH_AIN4P_AIN4M	4 /* AIN4(+) - AIN4(-) */
99 #define AD7795_CH_AIN5P_AIN5M	5 /* AIN5(+) - AIN5(-) */
100 #define AD7795_CH_AIN6P_AIN6M	6 /* AIN6(+) - AIN6(-) */
101 #define AD7795_CH_AIN1M_AIN1M	8 /* AIN1(-) - AIN1(-) */
102 
103 /* ID Register Bit Designations (AD7793_REG_ID) */
104 #define AD7785_ID		0x3
105 #define AD7792_ID		0xA
106 #define AD7793_ID		0xB
107 #define AD7794_ID		0xF
108 #define AD7795_ID		0xF
109 #define AD7796_ID		0xA
110 #define AD7797_ID		0xB
111 #define AD7798_ID		0x8
112 #define AD7799_ID		0x9
113 #define AD7793_ID_MASK		0xF
114 
115 /* IO (Excitation Current Sources) Register Bit Designations (AD7793_REG_IO) */
116 #define AD7793_IO_IEXC1_IOUT1_IEXC2_IOUT2	0 /* IEXC1 connect to IOUT1,
117 						   * IEXC2 connect to IOUT2 */
118 #define AD7793_IO_IEXC1_IOUT2_IEXC2_IOUT1	1 /* IEXC1 connect to IOUT2,
119 						   * IEXC2 connect to IOUT1 */
120 #define AD7793_IO_IEXC1_IEXC2_IOUT1		2 /* Both current sources
121 						   * IEXC1,2 connect to IOUT1 */
122 #define AD7793_IO_IEXC1_IEXC2_IOUT2		3 /* Both current sources
123 						   * IEXC1,2 connect to IOUT2 */
124 
125 #define AD7793_IO_IXCEN_10uA	(1 << 0) /* Excitation Current 10uA */
126 #define AD7793_IO_IXCEN_210uA	(2 << 0) /* Excitation Current 210uA */
127 #define AD7793_IO_IXCEN_1mA	(3 << 0) /* Excitation Current 1mA */
128 
129 /* NOTE:
130  * The AD7792/AD7793 features a dual use data out ready DOUT/RDY output.
131  * In order to avoid contentions on the SPI bus, it's therefore necessary
132  * to use spi bus locking.
133  *
134  * The DOUT/RDY output must also be wired to an interrupt capable GPIO.
135  */
136 
137 #define AD7793_FLAG_HAS_CLKSEL		BIT(0)
138 #define AD7793_FLAG_HAS_REFSEL		BIT(1)
139 #define AD7793_FLAG_HAS_VBIAS		BIT(2)
140 #define AD7793_HAS_EXITATION_CURRENT	BIT(3)
141 #define AD7793_FLAG_HAS_GAIN		BIT(4)
142 #define AD7793_FLAG_HAS_BUFFER		BIT(5)
143 
144 struct ad7793_chip_info {
145 	unsigned int id;
146 	const struct iio_chan_spec *channels;
147 	unsigned int num_channels;
148 	unsigned int flags;
149 
150 	const struct iio_info *iio_info;
151 	const u16 *sample_freq_avail;
152 };
153 
154 struct ad7793_state {
155 	const struct ad7793_chip_info	*chip_info;
156 	struct regulator		*reg;
157 	u16				int_vref_mv;
158 	u16				mode;
159 	u16				conf;
160 	u32				scale_avail[8][2];
161 
162 	struct ad_sigma_delta		sd;
163 
164 };
165 
166 enum ad7793_supported_device_ids {
167 	ID_AD7785,
168 	ID_AD7792,
169 	ID_AD7793,
170 	ID_AD7794,
171 	ID_AD7795,
172 	ID_AD7796,
173 	ID_AD7797,
174 	ID_AD7798,
175 	ID_AD7799,
176 };
177 
178 static struct ad7793_state *ad_sigma_delta_to_ad7793(struct ad_sigma_delta *sd)
179 {
180 	return container_of(sd, struct ad7793_state, sd);
181 }
182 
183 static int ad7793_set_channel(struct ad_sigma_delta *sd, unsigned int channel)
184 {
185 	struct ad7793_state *st = ad_sigma_delta_to_ad7793(sd);
186 
187 	st->conf &= ~AD7793_CONF_CHAN_MASK;
188 	st->conf |= AD7793_CONF_CHAN(channel);
189 
190 	return ad_sd_write_reg(&st->sd, AD7793_REG_CONF, 2, st->conf);
191 }
192 
193 static int ad7793_set_mode(struct ad_sigma_delta *sd,
194 			   enum ad_sigma_delta_mode mode)
195 {
196 	struct ad7793_state *st = ad_sigma_delta_to_ad7793(sd);
197 
198 	st->mode &= ~AD7793_MODE_SEL_MASK;
199 	st->mode |= AD7793_MODE_SEL(mode);
200 
201 	return ad_sd_write_reg(&st->sd, AD7793_REG_MODE, 2, st->mode);
202 }
203 
204 static const struct ad_sigma_delta_info ad7793_sigma_delta_info = {
205 	.set_channel = ad7793_set_channel,
206 	.set_mode = ad7793_set_mode,
207 	.has_registers = true,
208 	.addr_shift = 3,
209 	.read_mask = BIT(6),
210 };
211 
212 static const struct ad_sd_calib_data ad7793_calib_arr[6] = {
213 	{AD7793_MODE_CAL_INT_ZERO, AD7793_CH_AIN1P_AIN1M},
214 	{AD7793_MODE_CAL_INT_FULL, AD7793_CH_AIN1P_AIN1M},
215 	{AD7793_MODE_CAL_INT_ZERO, AD7793_CH_AIN2P_AIN2M},
216 	{AD7793_MODE_CAL_INT_FULL, AD7793_CH_AIN2P_AIN2M},
217 	{AD7793_MODE_CAL_INT_ZERO, AD7793_CH_AIN3P_AIN3M},
218 	{AD7793_MODE_CAL_INT_FULL, AD7793_CH_AIN3P_AIN3M}
219 };
220 
221 static int ad7793_calibrate_all(struct ad7793_state *st)
222 {
223 	return ad_sd_calibrate_all(&st->sd, ad7793_calib_arr,
224 				   ARRAY_SIZE(ad7793_calib_arr));
225 }
226 
227 static int ad7793_check_platform_data(struct ad7793_state *st,
228 	const struct ad7793_platform_data *pdata)
229 {
230 	if ((pdata->current_source_direction == AD7793_IEXEC1_IEXEC2_IOUT1 ||
231 		pdata->current_source_direction == AD7793_IEXEC1_IEXEC2_IOUT2) &&
232 		((pdata->exitation_current != AD7793_IX_10uA) &&
233 		(pdata->exitation_current != AD7793_IX_210uA)))
234 		return -EINVAL;
235 
236 	if (!(st->chip_info->flags & AD7793_FLAG_HAS_CLKSEL) &&
237 		pdata->clock_src != AD7793_CLK_SRC_INT)
238 		return -EINVAL;
239 
240 	if (!(st->chip_info->flags & AD7793_FLAG_HAS_REFSEL) &&
241 		pdata->refsel != AD7793_REFSEL_REFIN1)
242 		return -EINVAL;
243 
244 	if (!(st->chip_info->flags & AD7793_FLAG_HAS_VBIAS) &&
245 		pdata->bias_voltage != AD7793_BIAS_VOLTAGE_DISABLED)
246 		return -EINVAL;
247 
248 	if (!(st->chip_info->flags & AD7793_HAS_EXITATION_CURRENT) &&
249 		pdata->exitation_current != AD7793_IX_DISABLED)
250 		return -EINVAL;
251 
252 	return 0;
253 }
254 
255 static int ad7793_setup(struct iio_dev *indio_dev,
256 	const struct ad7793_platform_data *pdata,
257 	unsigned int vref_mv)
258 {
259 	struct ad7793_state *st = iio_priv(indio_dev);
260 	int i, ret = -1;
261 	unsigned long long scale_uv;
262 	u32 id;
263 
264 	ret = ad7793_check_platform_data(st, pdata);
265 	if (ret)
266 		return ret;
267 
268 	/* reset the serial interface */
269 	ret = spi_write(st->sd.spi, (u8 *)&ret, sizeof(ret));
270 	if (ret < 0)
271 		goto out;
272 	usleep_range(500, 2000); /* Wait for at least 500us */
273 
274 	/* write/read test for device presence */
275 	ret = ad_sd_read_reg(&st->sd, AD7793_REG_ID, 1, &id);
276 	if (ret)
277 		goto out;
278 
279 	id &= AD7793_ID_MASK;
280 
281 	if (id != st->chip_info->id) {
282 		dev_err(&st->sd.spi->dev, "device ID query failed\n");
283 		goto out;
284 	}
285 
286 	st->mode = AD7793_MODE_RATE(1);
287 	st->conf = 0;
288 
289 	if (st->chip_info->flags & AD7793_FLAG_HAS_CLKSEL)
290 		st->mode |= AD7793_MODE_CLKSRC(pdata->clock_src);
291 	if (st->chip_info->flags & AD7793_FLAG_HAS_REFSEL)
292 		st->conf |= AD7793_CONF_REFSEL(pdata->refsel);
293 	if (st->chip_info->flags & AD7793_FLAG_HAS_VBIAS)
294 		st->conf |= AD7793_CONF_VBIAS(pdata->bias_voltage);
295 	if (pdata->buffered || !(st->chip_info->flags & AD7793_FLAG_HAS_BUFFER))
296 		st->conf |= AD7793_CONF_BUF;
297 	if (pdata->boost_enable &&
298 		(st->chip_info->flags & AD7793_FLAG_HAS_VBIAS))
299 		st->conf |= AD7793_CONF_BOOST;
300 	if (pdata->burnout_current)
301 		st->conf |= AD7793_CONF_BO_EN;
302 	if (pdata->unipolar)
303 		st->conf |= AD7793_CONF_UNIPOLAR;
304 
305 	if (!(st->chip_info->flags & AD7793_FLAG_HAS_GAIN))
306 		st->conf |= AD7793_CONF_GAIN(7);
307 
308 	ret = ad7793_set_mode(&st->sd, AD_SD_MODE_IDLE);
309 	if (ret)
310 		goto out;
311 
312 	ret = ad7793_set_channel(&st->sd, 0);
313 	if (ret)
314 		goto out;
315 
316 	if (st->chip_info->flags & AD7793_HAS_EXITATION_CURRENT) {
317 		ret = ad_sd_write_reg(&st->sd, AD7793_REG_IO, 1,
318 				pdata->exitation_current |
319 				(pdata->current_source_direction << 2));
320 		if (ret)
321 			goto out;
322 	}
323 
324 	ret = ad7793_calibrate_all(st);
325 	if (ret)
326 		goto out;
327 
328 	/* Populate available ADC input ranges */
329 	for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++) {
330 		scale_uv = ((u64)vref_mv * 100000000)
331 			>> (st->chip_info->channels[0].scan_type.realbits -
332 			(!!(st->conf & AD7793_CONF_UNIPOLAR) ? 0 : 1));
333 		scale_uv >>= i;
334 
335 		st->scale_avail[i][1] = do_div(scale_uv, 100000000) * 10;
336 		st->scale_avail[i][0] = scale_uv;
337 	}
338 
339 	return 0;
340 out:
341 	dev_err(&st->sd.spi->dev, "setup failed\n");
342 	return ret;
343 }
344 
345 static const u16 ad7793_sample_freq_avail[16] = {0, 470, 242, 123, 62, 50, 39,
346 					33, 19, 17, 16, 12, 10, 8, 6, 4};
347 
348 static const u16 ad7797_sample_freq_avail[16] = {0, 0, 0, 123, 62, 50, 0,
349 					33, 0, 17, 16, 12, 10, 8, 6, 4};
350 
351 static ssize_t ad7793_read_frequency(struct device *dev,
352 		struct device_attribute *attr,
353 		char *buf)
354 {
355 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
356 	struct ad7793_state *st = iio_priv(indio_dev);
357 
358 	return sprintf(buf, "%d\n",
359 	       st->chip_info->sample_freq_avail[AD7793_MODE_RATE(st->mode)]);
360 }
361 
362 static ssize_t ad7793_write_frequency(struct device *dev,
363 		struct device_attribute *attr,
364 		const char *buf,
365 		size_t len)
366 {
367 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
368 	struct ad7793_state *st = iio_priv(indio_dev);
369 	long lval;
370 	int i, ret;
371 
372 	mutex_lock(&indio_dev->mlock);
373 	if (iio_buffer_enabled(indio_dev)) {
374 		mutex_unlock(&indio_dev->mlock);
375 		return -EBUSY;
376 	}
377 	mutex_unlock(&indio_dev->mlock);
378 
379 	ret = kstrtol(buf, 10, &lval);
380 	if (ret)
381 		return ret;
382 
383 	if (lval == 0)
384 		return -EINVAL;
385 
386 	ret = -EINVAL;
387 
388 	for (i = 0; i < 16; i++)
389 		if (lval == st->chip_info->sample_freq_avail[i]) {
390 			mutex_lock(&indio_dev->mlock);
391 			st->mode &= ~AD7793_MODE_RATE(-1);
392 			st->mode |= AD7793_MODE_RATE(i);
393 			ad_sd_write_reg(&st->sd, AD7793_REG_MODE,
394 					 sizeof(st->mode), st->mode);
395 			mutex_unlock(&indio_dev->mlock);
396 			ret = 0;
397 		}
398 
399 	return ret ? ret : len;
400 }
401 
402 static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
403 		ad7793_read_frequency,
404 		ad7793_write_frequency);
405 
406 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(
407 	"470 242 123 62 50 39 33 19 17 16 12 10 8 6 4");
408 
409 static IIO_CONST_ATTR_NAMED(sampling_frequency_available_ad7797,
410 	sampling_frequency_available, "123 62 50 33 17 16 12 10 8 6 4");
411 
412 static ssize_t ad7793_show_scale_available(struct device *dev,
413 			struct device_attribute *attr, char *buf)
414 {
415 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
416 	struct ad7793_state *st = iio_priv(indio_dev);
417 	int i, len = 0;
418 
419 	for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
420 		len += sprintf(buf + len, "%d.%09u ", st->scale_avail[i][0],
421 			       st->scale_avail[i][1]);
422 
423 	len += sprintf(buf + len, "\n");
424 
425 	return len;
426 }
427 
428 static IIO_DEVICE_ATTR_NAMED(in_m_in_scale_available,
429 		in_voltage-voltage_scale_available, S_IRUGO,
430 		ad7793_show_scale_available, NULL, 0);
431 
432 static struct attribute *ad7793_attributes[] = {
433 	&iio_dev_attr_sampling_frequency.dev_attr.attr,
434 	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
435 	&iio_dev_attr_in_m_in_scale_available.dev_attr.attr,
436 	NULL
437 };
438 
439 static const struct attribute_group ad7793_attribute_group = {
440 	.attrs = ad7793_attributes,
441 };
442 
443 static struct attribute *ad7797_attributes[] = {
444 	&iio_dev_attr_sampling_frequency.dev_attr.attr,
445 	&iio_const_attr_sampling_frequency_available_ad7797.dev_attr.attr,
446 	NULL
447 };
448 
449 static const struct attribute_group ad7797_attribute_group = {
450 	.attrs = ad7797_attributes,
451 };
452 
453 static int ad7793_read_raw(struct iio_dev *indio_dev,
454 			   struct iio_chan_spec const *chan,
455 			   int *val,
456 			   int *val2,
457 			   long m)
458 {
459 	struct ad7793_state *st = iio_priv(indio_dev);
460 	int ret;
461 	unsigned long long scale_uv;
462 	bool unipolar = !!(st->conf & AD7793_CONF_UNIPOLAR);
463 
464 	switch (m) {
465 	case IIO_CHAN_INFO_RAW:
466 		ret = ad_sigma_delta_single_conversion(indio_dev, chan, val);
467 		if (ret < 0)
468 			return ret;
469 
470 		return IIO_VAL_INT;
471 
472 	case IIO_CHAN_INFO_SCALE:
473 		switch (chan->type) {
474 		case IIO_VOLTAGE:
475 			if (chan->differential) {
476 				*val = st->
477 					scale_avail[(st->conf >> 8) & 0x7][0];
478 				*val2 = st->
479 					scale_avail[(st->conf >> 8) & 0x7][1];
480 				return IIO_VAL_INT_PLUS_NANO;
481 			}
482 			/* 1170mV / 2^23 * 6 */
483 			scale_uv = (1170ULL * 1000000000ULL * 6ULL);
484 			break;
485 		case IIO_TEMP:
486 				/* 1170mV / 0.81 mV/C / 2^23 */
487 				scale_uv = 1444444444444444ULL;
488 			break;
489 		default:
490 			return -EINVAL;
491 		}
492 
493 		scale_uv >>= (chan->scan_type.realbits - (unipolar ? 0 : 1));
494 		*val = 0;
495 		*val2 = scale_uv;
496 		return IIO_VAL_INT_PLUS_NANO;
497 	case IIO_CHAN_INFO_OFFSET:
498 		if (!unipolar)
499 			*val = -(1 << (chan->scan_type.realbits - 1));
500 		else
501 			*val = 0;
502 
503 		/* Kelvin to Celsius */
504 		if (chan->type == IIO_TEMP) {
505 			unsigned long long offset;
506 			unsigned int shift;
507 
508 			shift = chan->scan_type.realbits - (unipolar ? 0 : 1);
509 			offset = 273ULL << shift;
510 			do_div(offset, 1444);
511 			*val -= offset;
512 		}
513 		return IIO_VAL_INT;
514 	}
515 	return -EINVAL;
516 }
517 
518 static int ad7793_write_raw(struct iio_dev *indio_dev,
519 			       struct iio_chan_spec const *chan,
520 			       int val,
521 			       int val2,
522 			       long mask)
523 {
524 	struct ad7793_state *st = iio_priv(indio_dev);
525 	int ret, i;
526 	unsigned int tmp;
527 
528 	mutex_lock(&indio_dev->mlock);
529 	if (iio_buffer_enabled(indio_dev)) {
530 		mutex_unlock(&indio_dev->mlock);
531 		return -EBUSY;
532 	}
533 
534 	switch (mask) {
535 	case IIO_CHAN_INFO_SCALE:
536 		ret = -EINVAL;
537 		for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
538 			if (val2 == st->scale_avail[i][1]) {
539 				ret = 0;
540 				tmp = st->conf;
541 				st->conf &= ~AD7793_CONF_GAIN(-1);
542 				st->conf |= AD7793_CONF_GAIN(i);
543 
544 				if (tmp == st->conf)
545 					break;
546 
547 				ad_sd_write_reg(&st->sd, AD7793_REG_CONF,
548 						sizeof(st->conf), st->conf);
549 				ad7793_calibrate_all(st);
550 				break;
551 			}
552 		break;
553 	default:
554 		ret = -EINVAL;
555 	}
556 
557 	mutex_unlock(&indio_dev->mlock);
558 	return ret;
559 }
560 
561 static int ad7793_write_raw_get_fmt(struct iio_dev *indio_dev,
562 			       struct iio_chan_spec const *chan,
563 			       long mask)
564 {
565 	return IIO_VAL_INT_PLUS_NANO;
566 }
567 
568 static const struct iio_info ad7793_info = {
569 	.read_raw = &ad7793_read_raw,
570 	.write_raw = &ad7793_write_raw,
571 	.write_raw_get_fmt = &ad7793_write_raw_get_fmt,
572 	.attrs = &ad7793_attribute_group,
573 	.validate_trigger = ad_sd_validate_trigger,
574 	.driver_module = THIS_MODULE,
575 };
576 
577 static const struct iio_info ad7797_info = {
578 	.read_raw = &ad7793_read_raw,
579 	.write_raw = &ad7793_write_raw,
580 	.write_raw_get_fmt = &ad7793_write_raw_get_fmt,
581 	.attrs = &ad7793_attribute_group,
582 	.validate_trigger = ad_sd_validate_trigger,
583 	.driver_module = THIS_MODULE,
584 };
585 
586 #define DECLARE_AD7793_CHANNELS(_name, _b, _sb, _s) \
587 const struct iio_chan_spec _name##_channels[] = { \
588 	AD_SD_DIFF_CHANNEL(0, 0, 0, AD7793_CH_AIN1P_AIN1M, (_b), (_sb), (_s)), \
589 	AD_SD_DIFF_CHANNEL(1, 1, 1, AD7793_CH_AIN2P_AIN2M, (_b), (_sb), (_s)), \
590 	AD_SD_DIFF_CHANNEL(2, 2, 2, AD7793_CH_AIN3P_AIN3M, (_b), (_sb), (_s)), \
591 	AD_SD_SHORTED_CHANNEL(3, 0, AD7793_CH_AIN1M_AIN1M, (_b), (_sb), (_s)), \
592 	AD_SD_TEMP_CHANNEL(4, AD7793_CH_TEMP, (_b), (_sb), (_s)), \
593 	AD_SD_SUPPLY_CHANNEL(5, 3, AD7793_CH_AVDD_MONITOR, (_b), (_sb), (_s)), \
594 	IIO_CHAN_SOFT_TIMESTAMP(6), \
595 }
596 
597 #define DECLARE_AD7795_CHANNELS(_name, _b, _sb) \
598 const struct iio_chan_spec _name##_channels[] = { \
599 	AD_SD_DIFF_CHANNEL(0, 0, 0, AD7793_CH_AIN1P_AIN1M, (_b), (_sb), 0), \
600 	AD_SD_DIFF_CHANNEL(1, 1, 1, AD7793_CH_AIN2P_AIN2M, (_b), (_sb), 0), \
601 	AD_SD_DIFF_CHANNEL(2, 2, 2, AD7793_CH_AIN3P_AIN3M, (_b), (_sb), 0), \
602 	AD_SD_DIFF_CHANNEL(3, 3, 3, AD7795_CH_AIN4P_AIN4M, (_b), (_sb), 0), \
603 	AD_SD_DIFF_CHANNEL(4, 4, 4, AD7795_CH_AIN5P_AIN5M, (_b), (_sb), 0), \
604 	AD_SD_DIFF_CHANNEL(5, 5, 5, AD7795_CH_AIN6P_AIN6M, (_b), (_sb), 0), \
605 	AD_SD_SHORTED_CHANNEL(6, 0, AD7795_CH_AIN1M_AIN1M, (_b), (_sb), 0), \
606 	AD_SD_TEMP_CHANNEL(7, AD7793_CH_TEMP, (_b), (_sb), 0), \
607 	AD_SD_SUPPLY_CHANNEL(8, 3, AD7793_CH_AVDD_MONITOR, (_b), (_sb), 0), \
608 	IIO_CHAN_SOFT_TIMESTAMP(9), \
609 }
610 
611 #define DECLARE_AD7797_CHANNELS(_name, _b, _sb) \
612 const struct iio_chan_spec _name##_channels[] = { \
613 	AD_SD_DIFF_CHANNEL(0, 0, 0, AD7793_CH_AIN1P_AIN1M, (_b), (_sb), 0), \
614 	AD_SD_SHORTED_CHANNEL(1, 0, AD7793_CH_AIN1M_AIN1M, (_b), (_sb), 0), \
615 	AD_SD_TEMP_CHANNEL(2, AD7793_CH_TEMP, (_b), (_sb), 0), \
616 	AD_SD_SUPPLY_CHANNEL(3, 3, AD7793_CH_AVDD_MONITOR, (_b), (_sb), 0), \
617 	IIO_CHAN_SOFT_TIMESTAMP(4), \
618 }
619 
620 #define DECLARE_AD7799_CHANNELS(_name, _b, _sb) \
621 const struct iio_chan_spec _name##_channels[] = { \
622 	AD_SD_DIFF_CHANNEL(0, 0, 0, AD7793_CH_AIN1P_AIN1M, (_b), (_sb), 0), \
623 	AD_SD_DIFF_CHANNEL(1, 1, 1, AD7793_CH_AIN2P_AIN2M, (_b), (_sb), 0), \
624 	AD_SD_DIFF_CHANNEL(2, 2, 2, AD7793_CH_AIN3P_AIN3M, (_b), (_sb), 0), \
625 	AD_SD_SHORTED_CHANNEL(3, 0, AD7793_CH_AIN1M_AIN1M, (_b), (_sb), 0), \
626 	AD_SD_SUPPLY_CHANNEL(4, 3, AD7793_CH_AVDD_MONITOR, (_b), (_sb), 0), \
627 	IIO_CHAN_SOFT_TIMESTAMP(5), \
628 }
629 
630 static DECLARE_AD7793_CHANNELS(ad7785, 20, 32, 4);
631 static DECLARE_AD7793_CHANNELS(ad7792, 16, 32, 0);
632 static DECLARE_AD7793_CHANNELS(ad7793, 24, 32, 0);
633 static DECLARE_AD7795_CHANNELS(ad7794, 16, 32);
634 static DECLARE_AD7795_CHANNELS(ad7795, 24, 32);
635 static DECLARE_AD7797_CHANNELS(ad7796, 16, 16);
636 static DECLARE_AD7797_CHANNELS(ad7797, 24, 32);
637 static DECLARE_AD7799_CHANNELS(ad7798, 16, 16);
638 static DECLARE_AD7799_CHANNELS(ad7799, 24, 32);
639 
640 static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
641 	[ID_AD7785] = {
642 		.id = AD7785_ID,
643 		.channels = ad7785_channels,
644 		.num_channels = ARRAY_SIZE(ad7785_channels),
645 		.iio_info = &ad7793_info,
646 		.sample_freq_avail = ad7793_sample_freq_avail,
647 		.flags = AD7793_FLAG_HAS_CLKSEL |
648 			AD7793_FLAG_HAS_REFSEL |
649 			AD7793_FLAG_HAS_VBIAS |
650 			AD7793_HAS_EXITATION_CURRENT |
651 			AD7793_FLAG_HAS_GAIN |
652 			AD7793_FLAG_HAS_BUFFER,
653 	},
654 	[ID_AD7792] = {
655 		.id = AD7792_ID,
656 		.channels = ad7792_channels,
657 		.num_channels = ARRAY_SIZE(ad7792_channels),
658 		.iio_info = &ad7793_info,
659 		.sample_freq_avail = ad7793_sample_freq_avail,
660 		.flags = AD7793_FLAG_HAS_CLKSEL |
661 			AD7793_FLAG_HAS_REFSEL |
662 			AD7793_FLAG_HAS_VBIAS |
663 			AD7793_HAS_EXITATION_CURRENT |
664 			AD7793_FLAG_HAS_GAIN |
665 			AD7793_FLAG_HAS_BUFFER,
666 	},
667 	[ID_AD7793] = {
668 		.id = AD7793_ID,
669 		.channels = ad7793_channels,
670 		.num_channels = ARRAY_SIZE(ad7793_channels),
671 		.iio_info = &ad7793_info,
672 		.sample_freq_avail = ad7793_sample_freq_avail,
673 		.flags = AD7793_FLAG_HAS_CLKSEL |
674 			AD7793_FLAG_HAS_REFSEL |
675 			AD7793_FLAG_HAS_VBIAS |
676 			AD7793_HAS_EXITATION_CURRENT |
677 			AD7793_FLAG_HAS_GAIN |
678 			AD7793_FLAG_HAS_BUFFER,
679 	},
680 	[ID_AD7794] = {
681 		.id = AD7794_ID,
682 		.channels = ad7794_channels,
683 		.num_channels = ARRAY_SIZE(ad7794_channels),
684 		.iio_info = &ad7793_info,
685 		.sample_freq_avail = ad7793_sample_freq_avail,
686 		.flags = AD7793_FLAG_HAS_CLKSEL |
687 			AD7793_FLAG_HAS_REFSEL |
688 			AD7793_FLAG_HAS_VBIAS |
689 			AD7793_HAS_EXITATION_CURRENT |
690 			AD7793_FLAG_HAS_GAIN |
691 			AD7793_FLAG_HAS_BUFFER,
692 	},
693 	[ID_AD7795] = {
694 		.id = AD7795_ID,
695 		.channels = ad7795_channels,
696 		.num_channels = ARRAY_SIZE(ad7795_channels),
697 		.iio_info = &ad7793_info,
698 		.sample_freq_avail = ad7793_sample_freq_avail,
699 		.flags = AD7793_FLAG_HAS_CLKSEL |
700 			AD7793_FLAG_HAS_REFSEL |
701 			AD7793_FLAG_HAS_VBIAS |
702 			AD7793_HAS_EXITATION_CURRENT |
703 			AD7793_FLAG_HAS_GAIN |
704 			AD7793_FLAG_HAS_BUFFER,
705 	},
706 	[ID_AD7796] = {
707 		.id = AD7796_ID,
708 		.channels = ad7796_channels,
709 		.num_channels = ARRAY_SIZE(ad7796_channels),
710 		.iio_info = &ad7797_info,
711 		.sample_freq_avail = ad7797_sample_freq_avail,
712 		.flags = AD7793_FLAG_HAS_CLKSEL,
713 	},
714 	[ID_AD7797] = {
715 		.id = AD7797_ID,
716 		.channels = ad7797_channels,
717 		.num_channels = ARRAY_SIZE(ad7797_channels),
718 		.iio_info = &ad7797_info,
719 		.sample_freq_avail = ad7797_sample_freq_avail,
720 		.flags = AD7793_FLAG_HAS_CLKSEL,
721 	},
722 	[ID_AD7798] = {
723 		.id = AD7798_ID,
724 		.channels = ad7798_channels,
725 		.num_channels = ARRAY_SIZE(ad7798_channels),
726 		.iio_info = &ad7793_info,
727 		.sample_freq_avail = ad7793_sample_freq_avail,
728 		.flags = AD7793_FLAG_HAS_GAIN |
729 			AD7793_FLAG_HAS_BUFFER,
730 	},
731 	[ID_AD7799] = {
732 		.id = AD7799_ID,
733 		.channels = ad7799_channels,
734 		.num_channels = ARRAY_SIZE(ad7799_channels),
735 		.iio_info = &ad7793_info,
736 		.sample_freq_avail = ad7793_sample_freq_avail,
737 		.flags = AD7793_FLAG_HAS_GAIN |
738 			AD7793_FLAG_HAS_BUFFER,
739 	},
740 };
741 
742 static int ad7793_probe(struct spi_device *spi)
743 {
744 	const struct ad7793_platform_data *pdata = spi->dev.platform_data;
745 	struct ad7793_state *st;
746 	struct iio_dev *indio_dev;
747 	int ret, vref_mv = 0;
748 
749 	if (!pdata) {
750 		dev_err(&spi->dev, "no platform data?\n");
751 		return -ENODEV;
752 	}
753 
754 	if (!spi->irq) {
755 		dev_err(&spi->dev, "no IRQ?\n");
756 		return -ENODEV;
757 	}
758 
759 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
760 	if (indio_dev == NULL)
761 		return -ENOMEM;
762 
763 	st = iio_priv(indio_dev);
764 
765 	ad_sd_init(&st->sd, indio_dev, spi, &ad7793_sigma_delta_info);
766 
767 	if (pdata->refsel != AD7793_REFSEL_INTERNAL) {
768 		st->reg = devm_regulator_get(&spi->dev, "refin");
769 		if (IS_ERR(st->reg))
770 			return PTR_ERR(st->reg);
771 
772 		ret = regulator_enable(st->reg);
773 		if (ret)
774 			return ret;
775 
776 		vref_mv = regulator_get_voltage(st->reg);
777 		if (vref_mv < 0) {
778 			ret = vref_mv;
779 			goto error_disable_reg;
780 		}
781 
782 		vref_mv /= 1000;
783 	} else {
784 		vref_mv = 1170; /* Build-in ref */
785 	}
786 
787 	st->chip_info =
788 		&ad7793_chip_info_tbl[spi_get_device_id(spi)->driver_data];
789 
790 	spi_set_drvdata(spi, indio_dev);
791 
792 	indio_dev->dev.parent = &spi->dev;
793 	indio_dev->name = spi_get_device_id(spi)->name;
794 	indio_dev->modes = INDIO_DIRECT_MODE;
795 	indio_dev->channels = st->chip_info->channels;
796 	indio_dev->num_channels = st->chip_info->num_channels;
797 	indio_dev->info = st->chip_info->iio_info;
798 
799 	ret = ad_sd_setup_buffer_and_trigger(indio_dev);
800 	if (ret)
801 		goto error_disable_reg;
802 
803 	ret = ad7793_setup(indio_dev, pdata, vref_mv);
804 	if (ret)
805 		goto error_remove_trigger;
806 
807 	ret = iio_device_register(indio_dev);
808 	if (ret)
809 		goto error_remove_trigger;
810 
811 	return 0;
812 
813 error_remove_trigger:
814 	ad_sd_cleanup_buffer_and_trigger(indio_dev);
815 error_disable_reg:
816 	if (pdata->refsel != AD7793_REFSEL_INTERNAL)
817 		regulator_disable(st->reg);
818 
819 	return ret;
820 }
821 
822 static int ad7793_remove(struct spi_device *spi)
823 {
824 	const struct ad7793_platform_data *pdata = spi->dev.platform_data;
825 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
826 	struct ad7793_state *st = iio_priv(indio_dev);
827 
828 	iio_device_unregister(indio_dev);
829 	ad_sd_cleanup_buffer_and_trigger(indio_dev);
830 
831 	if (pdata->refsel != AD7793_REFSEL_INTERNAL)
832 		regulator_disable(st->reg);
833 
834 	return 0;
835 }
836 
837 static const struct spi_device_id ad7793_id[] = {
838 	{"ad7785", ID_AD7785},
839 	{"ad7792", ID_AD7792},
840 	{"ad7793", ID_AD7793},
841 	{"ad7794", ID_AD7794},
842 	{"ad7795", ID_AD7795},
843 	{"ad7796", ID_AD7796},
844 	{"ad7797", ID_AD7797},
845 	{"ad7798", ID_AD7798},
846 	{"ad7799", ID_AD7799},
847 	{}
848 };
849 MODULE_DEVICE_TABLE(spi, ad7793_id);
850 
851 static struct spi_driver ad7793_driver = {
852 	.driver = {
853 		.name	= "ad7793",
854 	},
855 	.probe		= ad7793_probe,
856 	.remove		= ad7793_remove,
857 	.id_table	= ad7793_id,
858 };
859 module_spi_driver(ad7793_driver);
860 
861 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
862 MODULE_DESCRIPTION("Analog Devices AD7793 and similar ADCs");
863 MODULE_LICENSE("GPL v2");
864