xref: /linux/drivers/iio/adc/ti-ads7950.c (revision cb4eb6771c0f8fd1c52a8f6fdec7762fb087380a)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Texas Instruments ADS7950 SPI ADC driver
4  *
5  * Copyright 2016 David Lechner <david@lechnology.com>
6  *
7  * Based on iio/ad7923.c:
8  * Copyright 2011 Analog Devices Inc
9  * Copyright 2012 CS Systemes d'Information
10  *
11  * And also on hwmon/ads79xx.c
12  * Copyright (C) 2013 Texas Instruments Incorporated - https://www.ti.com/
13  *	Nishanth Menon
14  */
15 
16 #include <linux/acpi.h>
17 #include <linux/bitops.h>
18 #include <linux/device.h>
19 #include <linux/err.h>
20 #include <linux/gpio/driver.h>
21 #include <linux/interrupt.h>
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/regulator/consumer.h>
25 #include <linux/slab.h>
26 #include <linux/spi/spi.h>
27 
28 #include <linux/iio/buffer.h>
29 #include <linux/iio/iio.h>
30 #include <linux/iio/sysfs.h>
31 #include <linux/iio/trigger_consumer.h>
32 #include <linux/iio/triggered_buffer.h>
33 
34 /*
35  * In case of ACPI, we use the 5000 mV as default for the reference pin.
36  * Device tree users encode that via the vref-supply regulator.
37  */
38 #define TI_ADS7950_VA_MV_ACPI_DEFAULT	5000
39 
40 #define TI_ADS7950_CR_GPIO	BIT(14)
41 #define TI_ADS7950_CR_MANUAL	BIT(12)
42 #define TI_ADS7950_CR_WRITE	BIT(11)
43 #define TI_ADS7950_CR_CHAN(ch)	((ch) << 7)
44 #define TI_ADS7950_CR_RANGE_5V	BIT(6)
45 #define TI_ADS7950_CR_GPIO_DATA	BIT(4)
46 
47 #define TI_ADS7950_MAX_CHAN	16
48 #define TI_ADS7950_NUM_GPIOS	4
49 
50 /* val = value, dec = left shift, bits = number of bits of the mask */
51 #define TI_ADS7950_EXTRACT(val, dec, bits) \
52 	(((val) >> (dec)) & ((1 << (bits)) - 1))
53 
54 #define TI_ADS7950_MAN_CMD(cmd)         (TI_ADS7950_CR_MANUAL | (cmd))
55 #define TI_ADS7950_GPIO_CMD(cmd)        (TI_ADS7950_CR_GPIO | (cmd))
56 
57 /* Manual mode configuration */
58 #define TI_ADS7950_MAN_CMD_SETTINGS(st) \
59 	(TI_ADS7950_MAN_CMD(TI_ADS7950_CR_WRITE | st->cmd_settings_bitmask))
60 /* GPIO mode configuration */
61 #define TI_ADS7950_GPIO_CMD_SETTINGS(st) \
62 	(TI_ADS7950_GPIO_CMD(st->gpio_cmd_settings_bitmask))
63 
64 struct ti_ads7950_state {
65 	struct spi_device	*spi;
66 	struct spi_transfer	ring_xfer;
67 	struct spi_transfer	scan_single_xfer[3];
68 	struct spi_message	ring_msg;
69 	struct spi_message	scan_single_msg;
70 
71 	/* Lock to protect the spi xfer buffers */
72 	struct mutex		slock;
73 	struct gpio_chip	chip;
74 
75 	struct regulator	*reg;
76 	unsigned int		vref_mv;
77 
78 	/*
79 	 * Bitmask of lower 7 bits used for configuration
80 	 * These bits only can be written when TI_ADS7950_CR_WRITE
81 	 * is set, otherwise it retains its original state.
82 	 * [0-3] GPIO signal
83 	 * [4]   Set following frame to return GPIO signal values
84 	 * [5]   Powers down device
85 	 * [6]   Sets Vref range1(2.5v) or range2(5v)
86 	 *
87 	 * Bits present on Manual/Auto1/Auto2 commands
88 	 */
89 	unsigned int		cmd_settings_bitmask;
90 
91 	/*
92 	 * Bitmask of GPIO command
93 	 * [0-3] GPIO direction
94 	 * [4-6] Different GPIO alarm mode configurations
95 	 * [7]   GPIO 2 as device range input
96 	 * [8]   GPIO 3 as device power down input
97 	 * [9]   Reset all registers
98 	 * [10-11] N/A
99 	 */
100 	unsigned int		gpio_cmd_settings_bitmask;
101 
102 	/*
103 	 * DMA (thus cache coherency maintenance) may require the
104 	 * transfer buffers to live in their own cache lines.
105 	 */
106 	u16 rx_buf[TI_ADS7950_MAX_CHAN + 2] __aligned(IIO_DMA_MINALIGN);
107 	u16 tx_buf[TI_ADS7950_MAX_CHAN + 2];
108 	u16 single_tx;
109 	u16 single_rx;
110 
111 };
112 
113 struct ti_ads7950_chip_info {
114 	const struct iio_chan_spec *channels;
115 	unsigned int num_channels;
116 };
117 
118 #define TI_ADS7950_V_CHAN(index, bits)				\
119 {								\
120 	.type = IIO_VOLTAGE,					\
121 	.indexed = 1,						\
122 	.channel = index,					\
123 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
124 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
125 	.address = index,					\
126 	.datasheet_name = "CH##index",				\
127 	.scan_index = index,					\
128 	.scan_type = {						\
129 		.sign = 'u',					\
130 		.realbits = bits,				\
131 		.storagebits = 16,				\
132 		.shift = 12 - (bits),				\
133 		.endianness = IIO_CPU,				\
134 	},							\
135 }
136 
137 #define DECLARE_TI_ADS7950_4_CHANNELS(name, bits) \
138 const struct iio_chan_spec name ## _channels[] = { \
139 	TI_ADS7950_V_CHAN(0, bits), \
140 	TI_ADS7950_V_CHAN(1, bits), \
141 	TI_ADS7950_V_CHAN(2, bits), \
142 	TI_ADS7950_V_CHAN(3, bits), \
143 	IIO_CHAN_SOFT_TIMESTAMP(4), \
144 }
145 
146 #define DECLARE_TI_ADS7950_8_CHANNELS(name, bits) \
147 const struct iio_chan_spec name ## _channels[] = { \
148 	TI_ADS7950_V_CHAN(0, bits), \
149 	TI_ADS7950_V_CHAN(1, bits), \
150 	TI_ADS7950_V_CHAN(2, bits), \
151 	TI_ADS7950_V_CHAN(3, bits), \
152 	TI_ADS7950_V_CHAN(4, bits), \
153 	TI_ADS7950_V_CHAN(5, bits), \
154 	TI_ADS7950_V_CHAN(6, bits), \
155 	TI_ADS7950_V_CHAN(7, bits), \
156 	IIO_CHAN_SOFT_TIMESTAMP(8), \
157 }
158 
159 #define DECLARE_TI_ADS7950_12_CHANNELS(name, bits) \
160 const struct iio_chan_spec name ## _channels[] = { \
161 	TI_ADS7950_V_CHAN(0, bits), \
162 	TI_ADS7950_V_CHAN(1, bits), \
163 	TI_ADS7950_V_CHAN(2, bits), \
164 	TI_ADS7950_V_CHAN(3, bits), \
165 	TI_ADS7950_V_CHAN(4, bits), \
166 	TI_ADS7950_V_CHAN(5, bits), \
167 	TI_ADS7950_V_CHAN(6, bits), \
168 	TI_ADS7950_V_CHAN(7, bits), \
169 	TI_ADS7950_V_CHAN(8, bits), \
170 	TI_ADS7950_V_CHAN(9, bits), \
171 	TI_ADS7950_V_CHAN(10, bits), \
172 	TI_ADS7950_V_CHAN(11, bits), \
173 	IIO_CHAN_SOFT_TIMESTAMP(12), \
174 }
175 
176 #define DECLARE_TI_ADS7950_16_CHANNELS(name, bits) \
177 const struct iio_chan_spec name ## _channels[] = { \
178 	TI_ADS7950_V_CHAN(0, bits), \
179 	TI_ADS7950_V_CHAN(1, bits), \
180 	TI_ADS7950_V_CHAN(2, bits), \
181 	TI_ADS7950_V_CHAN(3, bits), \
182 	TI_ADS7950_V_CHAN(4, bits), \
183 	TI_ADS7950_V_CHAN(5, bits), \
184 	TI_ADS7950_V_CHAN(6, bits), \
185 	TI_ADS7950_V_CHAN(7, bits), \
186 	TI_ADS7950_V_CHAN(8, bits), \
187 	TI_ADS7950_V_CHAN(9, bits), \
188 	TI_ADS7950_V_CHAN(10, bits), \
189 	TI_ADS7950_V_CHAN(11, bits), \
190 	TI_ADS7950_V_CHAN(12, bits), \
191 	TI_ADS7950_V_CHAN(13, bits), \
192 	TI_ADS7950_V_CHAN(14, bits), \
193 	TI_ADS7950_V_CHAN(15, bits), \
194 	IIO_CHAN_SOFT_TIMESTAMP(16), \
195 }
196 
197 static DECLARE_TI_ADS7950_4_CHANNELS(ti_ads7950, 12);
198 static DECLARE_TI_ADS7950_8_CHANNELS(ti_ads7951, 12);
199 static DECLARE_TI_ADS7950_12_CHANNELS(ti_ads7952, 12);
200 static DECLARE_TI_ADS7950_16_CHANNELS(ti_ads7953, 12);
201 static DECLARE_TI_ADS7950_4_CHANNELS(ti_ads7954, 10);
202 static DECLARE_TI_ADS7950_8_CHANNELS(ti_ads7955, 10);
203 static DECLARE_TI_ADS7950_12_CHANNELS(ti_ads7956, 10);
204 static DECLARE_TI_ADS7950_16_CHANNELS(ti_ads7957, 10);
205 static DECLARE_TI_ADS7950_4_CHANNELS(ti_ads7958, 8);
206 static DECLARE_TI_ADS7950_8_CHANNELS(ti_ads7959, 8);
207 static DECLARE_TI_ADS7950_12_CHANNELS(ti_ads7960, 8);
208 static DECLARE_TI_ADS7950_16_CHANNELS(ti_ads7961, 8);
209 
210 static const struct ti_ads7950_chip_info ti_ads7950_chip_info = {
211 	.channels	= ti_ads7950_channels,
212 	.num_channels	= ARRAY_SIZE(ti_ads7950_channels),
213 };
214 
215 static const struct ti_ads7950_chip_info ti_ads7951_chip_info = {
216 	.channels	= ti_ads7951_channels,
217 	.num_channels	= ARRAY_SIZE(ti_ads7951_channels),
218 };
219 
220 static const struct ti_ads7950_chip_info ti_ads7952_chip_info = {
221 	.channels	= ti_ads7952_channels,
222 	.num_channels	= ARRAY_SIZE(ti_ads7952_channels),
223 };
224 
225 static const struct ti_ads7950_chip_info ti_ads7953_chip_info = {
226 	.channels	= ti_ads7953_channels,
227 	.num_channels	= ARRAY_SIZE(ti_ads7953_channels),
228 };
229 
230 static const struct ti_ads7950_chip_info ti_ads7954_chip_info = {
231 	.channels	= ti_ads7954_channels,
232 	.num_channels	= ARRAY_SIZE(ti_ads7954_channels),
233 };
234 
235 static const struct ti_ads7950_chip_info ti_ads7955_chip_info = {
236 	.channels	= ti_ads7955_channels,
237 	.num_channels	= ARRAY_SIZE(ti_ads7955_channels),
238 };
239 
240 static const struct ti_ads7950_chip_info ti_ads7956_chip_info = {
241 	.channels	= ti_ads7956_channels,
242 	.num_channels	= ARRAY_SIZE(ti_ads7956_channels),
243 };
244 
245 static const struct ti_ads7950_chip_info ti_ads7957_chip_info = {
246 	.channels	= ti_ads7957_channels,
247 	.num_channels	= ARRAY_SIZE(ti_ads7957_channels),
248 };
249 
250 static const struct ti_ads7950_chip_info ti_ads7958_chip_info = {
251 	.channels	= ti_ads7958_channels,
252 	.num_channels	= ARRAY_SIZE(ti_ads7958_channels),
253 };
254 
255 static const struct ti_ads7950_chip_info ti_ads7959_chip_info = {
256 	.channels	= ti_ads7959_channels,
257 	.num_channels	= ARRAY_SIZE(ti_ads7959_channels),
258 };
259 
260 static const struct ti_ads7950_chip_info ti_ads7960_chip_info = {
261 	.channels	= ti_ads7960_channels,
262 	.num_channels	= ARRAY_SIZE(ti_ads7960_channels),
263 };
264 
265 static const struct ti_ads7950_chip_info ti_ads7961_chip_info = {
266 	.channels	= ti_ads7961_channels,
267 	.num_channels	= ARRAY_SIZE(ti_ads7961_channels),
268 };
269 
270 /*
271  * ti_ads7950_update_scan_mode() setup the spi transfer buffer for the new
272  * scan mask
273  */
ti_ads7950_update_scan_mode(struct iio_dev * indio_dev,const unsigned long * active_scan_mask)274 static int ti_ads7950_update_scan_mode(struct iio_dev *indio_dev,
275 				       const unsigned long *active_scan_mask)
276 {
277 	struct ti_ads7950_state *st = iio_priv(indio_dev);
278 	int i, cmd, len;
279 
280 	len = 0;
281 	for_each_set_bit(i, active_scan_mask, indio_dev->num_channels) {
282 		cmd = TI_ADS7950_MAN_CMD(TI_ADS7950_CR_CHAN(i));
283 		st->tx_buf[len++] = cmd;
284 	}
285 
286 	/* Data for the 1st channel is not returned until the 3rd transfer */
287 	st->tx_buf[len++] = 0;
288 	st->tx_buf[len++] = 0;
289 
290 	st->ring_xfer.len = len * 2;
291 
292 	return 0;
293 }
294 
ti_ads7950_trigger_handler(int irq,void * p)295 static irqreturn_t ti_ads7950_trigger_handler(int irq, void *p)
296 {
297 	struct iio_poll_func *pf = p;
298 	struct iio_dev *indio_dev = pf->indio_dev;
299 	struct ti_ads7950_state *st = iio_priv(indio_dev);
300 	int ret;
301 
302 	mutex_lock(&st->slock);
303 	ret = spi_sync(st->spi, &st->ring_msg);
304 	if (ret < 0)
305 		goto out;
306 
307 	iio_push_to_buffers_with_ts_unaligned(indio_dev, &st->rx_buf[2],
308 					      sizeof(*st->rx_buf) *
309 					      TI_ADS7950_MAX_CHAN,
310 					      iio_get_time_ns(indio_dev));
311 
312 out:
313 	mutex_unlock(&st->slock);
314 	iio_trigger_notify_done(indio_dev->trig);
315 
316 	return IRQ_HANDLED;
317 }
318 
ti_ads7950_scan_direct(struct iio_dev * indio_dev,unsigned int ch)319 static int ti_ads7950_scan_direct(struct iio_dev *indio_dev, unsigned int ch)
320 {
321 	struct ti_ads7950_state *st = iio_priv(indio_dev);
322 	int ret, cmd;
323 
324 	mutex_lock(&st->slock);
325 	cmd = TI_ADS7950_MAN_CMD(TI_ADS7950_CR_CHAN(ch));
326 	st->single_tx = cmd;
327 
328 	ret = spi_sync(st->spi, &st->scan_single_msg);
329 	if (ret)
330 		goto out;
331 
332 	ret = st->single_rx;
333 
334 out:
335 	mutex_unlock(&st->slock);
336 
337 	return ret;
338 }
339 
ti_ads7950_get_range(struct ti_ads7950_state * st)340 static int ti_ads7950_get_range(struct ti_ads7950_state *st)
341 {
342 	int vref;
343 
344 	if (st->vref_mv) {
345 		vref = st->vref_mv;
346 	} else {
347 		vref = regulator_get_voltage(st->reg);
348 		if (vref < 0)
349 			return vref;
350 
351 		vref /= 1000;
352 	}
353 
354 	if (st->cmd_settings_bitmask & TI_ADS7950_CR_RANGE_5V)
355 		vref *= 2;
356 
357 	return vref;
358 }
359 
ti_ads7950_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)360 static int ti_ads7950_read_raw(struct iio_dev *indio_dev,
361 			       struct iio_chan_spec const *chan,
362 			       int *val, int *val2, long m)
363 {
364 	struct ti_ads7950_state *st = iio_priv(indio_dev);
365 	int ret;
366 
367 	switch (m) {
368 	case IIO_CHAN_INFO_RAW:
369 		ret = ti_ads7950_scan_direct(indio_dev, chan->address);
370 		if (ret < 0)
371 			return ret;
372 
373 		if (chan->address != TI_ADS7950_EXTRACT(ret, 12, 4))
374 			return -EIO;
375 
376 		*val = TI_ADS7950_EXTRACT(ret, chan->scan_type.shift,
377 					  chan->scan_type.realbits);
378 
379 		return IIO_VAL_INT;
380 	case IIO_CHAN_INFO_SCALE:
381 		ret = ti_ads7950_get_range(st);
382 		if (ret < 0)
383 			return ret;
384 
385 		*val = ret;
386 		*val2 = (1 << chan->scan_type.realbits) - 1;
387 
388 		return IIO_VAL_FRACTIONAL;
389 	}
390 
391 	return -EINVAL;
392 }
393 
394 static const struct iio_info ti_ads7950_info = {
395 	.read_raw		= &ti_ads7950_read_raw,
396 	.update_scan_mode	= ti_ads7950_update_scan_mode,
397 };
398 
ti_ads7950_set(struct gpio_chip * chip,unsigned int offset,int value)399 static int ti_ads7950_set(struct gpio_chip *chip, unsigned int offset,
400 			  int value)
401 {
402 	struct ti_ads7950_state *st = gpiochip_get_data(chip);
403 	int ret;
404 
405 	mutex_lock(&st->slock);
406 
407 	if (value)
408 		st->cmd_settings_bitmask |= BIT(offset);
409 	else
410 		st->cmd_settings_bitmask &= ~BIT(offset);
411 
412 	st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);
413 	ret = spi_sync(st->spi, &st->scan_single_msg);
414 
415 	mutex_unlock(&st->slock);
416 
417 	return ret;
418 }
419 
ti_ads7950_get(struct gpio_chip * chip,unsigned int offset)420 static int ti_ads7950_get(struct gpio_chip *chip, unsigned int offset)
421 {
422 	struct ti_ads7950_state *st = gpiochip_get_data(chip);
423 	bool state;
424 	int ret;
425 
426 	mutex_lock(&st->slock);
427 
428 	/* If set as output, return the output */
429 	if (st->gpio_cmd_settings_bitmask & BIT(offset)) {
430 		state = st->cmd_settings_bitmask & BIT(offset);
431 		ret = 0;
432 		goto out;
433 	}
434 
435 	/* GPIO data bit sets SDO bits 12-15 to GPIO input */
436 	st->cmd_settings_bitmask |= TI_ADS7950_CR_GPIO_DATA;
437 	st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);
438 	ret = spi_sync(st->spi, &st->scan_single_msg);
439 	if (ret)
440 		goto out;
441 
442 	state = (st->single_rx >> 12) & BIT(offset);
443 
444 	/* Revert back to original settings */
445 	st->cmd_settings_bitmask &= ~TI_ADS7950_CR_GPIO_DATA;
446 	st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);
447 	ret = spi_sync(st->spi, &st->scan_single_msg);
448 	if (ret)
449 		goto out;
450 
451 out:
452 	mutex_unlock(&st->slock);
453 
454 	return ret ?: state;
455 }
456 
ti_ads7950_get_direction(struct gpio_chip * chip,unsigned int offset)457 static int ti_ads7950_get_direction(struct gpio_chip *chip,
458 				    unsigned int offset)
459 {
460 	struct ti_ads7950_state *st = gpiochip_get_data(chip);
461 
462 	/* Bitmask is inverted from GPIO framework 0=input/1=output */
463 	return !(st->gpio_cmd_settings_bitmask & BIT(offset));
464 }
465 
_ti_ads7950_set_direction(struct gpio_chip * chip,int offset,int input)466 static int _ti_ads7950_set_direction(struct gpio_chip *chip, int offset,
467 				     int input)
468 {
469 	struct ti_ads7950_state *st = gpiochip_get_data(chip);
470 	int ret = 0;
471 
472 	mutex_lock(&st->slock);
473 
474 	/* Only change direction if needed */
475 	if (input && (st->gpio_cmd_settings_bitmask & BIT(offset)))
476 		st->gpio_cmd_settings_bitmask &= ~BIT(offset);
477 	else if (!input && !(st->gpio_cmd_settings_bitmask & BIT(offset)))
478 		st->gpio_cmd_settings_bitmask |= BIT(offset);
479 	else
480 		goto out;
481 
482 	st->single_tx = TI_ADS7950_GPIO_CMD_SETTINGS(st);
483 	ret = spi_sync(st->spi, &st->scan_single_msg);
484 
485 out:
486 	mutex_unlock(&st->slock);
487 
488 	return ret;
489 }
490 
ti_ads7950_direction_input(struct gpio_chip * chip,unsigned int offset)491 static int ti_ads7950_direction_input(struct gpio_chip *chip,
492 				      unsigned int offset)
493 {
494 	return _ti_ads7950_set_direction(chip, offset, 1);
495 }
496 
ti_ads7950_direction_output(struct gpio_chip * chip,unsigned int offset,int value)497 static int ti_ads7950_direction_output(struct gpio_chip *chip,
498 				       unsigned int offset, int value)
499 {
500 	int ret;
501 
502 	ret = ti_ads7950_set(chip, offset, value);
503 	if (ret)
504 		return ret;
505 
506 	return _ti_ads7950_set_direction(chip, offset, 0);
507 }
508 
ti_ads7950_init_hw(struct ti_ads7950_state * st)509 static int ti_ads7950_init_hw(struct ti_ads7950_state *st)
510 {
511 	int ret = 0;
512 
513 	mutex_lock(&st->slock);
514 
515 	/* Settings for Manual/Auto1/Auto2 commands */
516 	/* Default to 5v ref */
517 	st->cmd_settings_bitmask = TI_ADS7950_CR_RANGE_5V;
518 	st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);
519 	ret = spi_sync(st->spi, &st->scan_single_msg);
520 	if (ret)
521 		goto out;
522 
523 	/* Settings for GPIO command */
524 	st->gpio_cmd_settings_bitmask = 0x0;
525 	st->single_tx = TI_ADS7950_GPIO_CMD_SETTINGS(st);
526 	ret = spi_sync(st->spi, &st->scan_single_msg);
527 
528 out:
529 	mutex_unlock(&st->slock);
530 
531 	return ret;
532 }
533 
ti_ads7950_probe(struct spi_device * spi)534 static int ti_ads7950_probe(struct spi_device *spi)
535 {
536 	struct ti_ads7950_state *st;
537 	struct iio_dev *indio_dev;
538 	const struct ti_ads7950_chip_info *info;
539 	int ret;
540 
541 	spi->bits_per_word = 16;
542 	spi->mode |= SPI_CS_WORD;
543 	ret = spi_setup(spi);
544 	if (ret < 0) {
545 		dev_err(&spi->dev, "Error in spi setup\n");
546 		return ret;
547 	}
548 
549 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
550 	if (!indio_dev)
551 		return -ENOMEM;
552 
553 	st = iio_priv(indio_dev);
554 
555 	spi_set_drvdata(spi, indio_dev);
556 
557 	st->spi = spi;
558 
559 	info = spi_get_device_match_data(spi);
560 
561 	indio_dev->name = spi_get_device_id(spi)->name;
562 	indio_dev->modes = INDIO_DIRECT_MODE;
563 	indio_dev->channels = info->channels;
564 	indio_dev->num_channels = info->num_channels;
565 	indio_dev->info = &ti_ads7950_info;
566 
567 	/* build spi ring message */
568 	spi_message_init(&st->ring_msg);
569 
570 	st->ring_xfer.tx_buf = &st->tx_buf[0];
571 	st->ring_xfer.rx_buf = &st->rx_buf[0];
572 	/* len will be set later */
573 
574 	spi_message_add_tail(&st->ring_xfer, &st->ring_msg);
575 
576 	/*
577 	 * Setup default message. The sample is read at the end of the first
578 	 * transfer, then it takes one full cycle to convert the sample and one
579 	 * more cycle to send the value. The conversion process is driven by
580 	 * the SPI clock, which is why we have 3 transfers. The middle one is
581 	 * just dummy data sent while the chip is converting the sample that
582 	 * was read at the end of the first transfer.
583 	 */
584 
585 	st->scan_single_xfer[0].tx_buf = &st->single_tx;
586 	st->scan_single_xfer[0].len = 2;
587 	st->scan_single_xfer[0].cs_change = 1;
588 	st->scan_single_xfer[1].tx_buf = &st->single_tx;
589 	st->scan_single_xfer[1].len = 2;
590 	st->scan_single_xfer[1].cs_change = 1;
591 	st->scan_single_xfer[2].rx_buf = &st->single_rx;
592 	st->scan_single_xfer[2].len = 2;
593 
594 	spi_message_init_with_transfers(&st->scan_single_msg,
595 					st->scan_single_xfer, 3);
596 
597 	/* Use hard coded value for reference voltage in ACPI case */
598 	if (ACPI_COMPANION(&spi->dev))
599 		st->vref_mv = TI_ADS7950_VA_MV_ACPI_DEFAULT;
600 
601 	mutex_init(&st->slock);
602 
603 	st->reg = devm_regulator_get(&spi->dev, "vref");
604 	if (IS_ERR(st->reg)) {
605 		ret = dev_err_probe(&spi->dev, PTR_ERR(st->reg),
606 				     "Failed to get regulator \"vref\"\n");
607 		goto error_destroy_mutex;
608 	}
609 
610 	ret = regulator_enable(st->reg);
611 	if (ret) {
612 		dev_err(&spi->dev, "Failed to enable regulator \"vref\"\n");
613 		goto error_destroy_mutex;
614 	}
615 
616 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
617 					 &ti_ads7950_trigger_handler, NULL);
618 	if (ret) {
619 		dev_err(&spi->dev, "Failed to setup triggered buffer\n");
620 		goto error_disable_reg;
621 	}
622 
623 	ret = ti_ads7950_init_hw(st);
624 	if (ret) {
625 		dev_err(&spi->dev, "Failed to init adc chip\n");
626 		goto error_cleanup_ring;
627 	}
628 
629 	ret = iio_device_register(indio_dev);
630 	if (ret) {
631 		dev_err(&spi->dev, "Failed to register iio device\n");
632 		goto error_cleanup_ring;
633 	}
634 
635 	/* Add GPIO chip */
636 	st->chip.label = dev_name(&st->spi->dev);
637 	st->chip.parent = &st->spi->dev;
638 	st->chip.owner = THIS_MODULE;
639 	st->chip.can_sleep = true;
640 	st->chip.base = -1;
641 	st->chip.ngpio = TI_ADS7950_NUM_GPIOS;
642 	st->chip.get_direction = ti_ads7950_get_direction;
643 	st->chip.direction_input = ti_ads7950_direction_input;
644 	st->chip.direction_output = ti_ads7950_direction_output;
645 	st->chip.get = ti_ads7950_get;
646 	st->chip.set = ti_ads7950_set;
647 
648 	ret = gpiochip_add_data(&st->chip, st);
649 	if (ret) {
650 		dev_err(&spi->dev, "Failed to init GPIOs\n");
651 		goto error_iio_device;
652 	}
653 
654 	return 0;
655 
656 error_iio_device:
657 	iio_device_unregister(indio_dev);
658 error_cleanup_ring:
659 	iio_triggered_buffer_cleanup(indio_dev);
660 error_disable_reg:
661 	regulator_disable(st->reg);
662 error_destroy_mutex:
663 	mutex_destroy(&st->slock);
664 
665 	return ret;
666 }
667 
ti_ads7950_remove(struct spi_device * spi)668 static void ti_ads7950_remove(struct spi_device *spi)
669 {
670 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
671 	struct ti_ads7950_state *st = iio_priv(indio_dev);
672 
673 	gpiochip_remove(&st->chip);
674 	iio_device_unregister(indio_dev);
675 	iio_triggered_buffer_cleanup(indio_dev);
676 	regulator_disable(st->reg);
677 	mutex_destroy(&st->slock);
678 }
679 
680 static const struct spi_device_id ti_ads7950_id[] = {
681 	{ "ads7950", (kernel_ulong_t)&ti_ads7950_chip_info },
682 	{ "ads7951", (kernel_ulong_t)&ti_ads7951_chip_info },
683 	{ "ads7952", (kernel_ulong_t)&ti_ads7952_chip_info },
684 	{ "ads7953", (kernel_ulong_t)&ti_ads7953_chip_info },
685 	{ "ads7954", (kernel_ulong_t)&ti_ads7954_chip_info },
686 	{ "ads7955", (kernel_ulong_t)&ti_ads7955_chip_info },
687 	{ "ads7956", (kernel_ulong_t)&ti_ads7956_chip_info },
688 	{ "ads7957", (kernel_ulong_t)&ti_ads7957_chip_info },
689 	{ "ads7958", (kernel_ulong_t)&ti_ads7958_chip_info },
690 	{ "ads7959", (kernel_ulong_t)&ti_ads7959_chip_info },
691 	{ "ads7960", (kernel_ulong_t)&ti_ads7960_chip_info },
692 	{ "ads7961", (kernel_ulong_t)&ti_ads7961_chip_info },
693 	{ }
694 };
695 MODULE_DEVICE_TABLE(spi, ti_ads7950_id);
696 
697 static const struct of_device_id ads7950_of_table[] = {
698 	{ .compatible = "ti,ads7950", .data = &ti_ads7950_chip_info },
699 	{ .compatible = "ti,ads7951", .data = &ti_ads7951_chip_info },
700 	{ .compatible = "ti,ads7952", .data = &ti_ads7952_chip_info },
701 	{ .compatible = "ti,ads7953", .data = &ti_ads7953_chip_info },
702 	{ .compatible = "ti,ads7954", .data = &ti_ads7954_chip_info },
703 	{ .compatible = "ti,ads7955", .data = &ti_ads7955_chip_info },
704 	{ .compatible = "ti,ads7956", .data = &ti_ads7956_chip_info },
705 	{ .compatible = "ti,ads7957", .data = &ti_ads7957_chip_info },
706 	{ .compatible = "ti,ads7958", .data = &ti_ads7958_chip_info },
707 	{ .compatible = "ti,ads7959", .data = &ti_ads7959_chip_info },
708 	{ .compatible = "ti,ads7960", .data = &ti_ads7960_chip_info },
709 	{ .compatible = "ti,ads7961", .data = &ti_ads7961_chip_info },
710 	{ }
711 };
712 MODULE_DEVICE_TABLE(of, ads7950_of_table);
713 
714 static struct spi_driver ti_ads7950_driver = {
715 	.driver = {
716 		.name	= "ads7950",
717 		.of_match_table = ads7950_of_table,
718 	},
719 	.probe		= ti_ads7950_probe,
720 	.remove		= ti_ads7950_remove,
721 	.id_table	= ti_ads7950_id,
722 };
723 module_spi_driver(ti_ads7950_driver);
724 
725 MODULE_AUTHOR("David Lechner <david@lechnology.com>");
726 MODULE_DESCRIPTION("TI TI_ADS7950 ADC");
727 MODULE_LICENSE("GPL v2");
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