1// SPDX-License-Identifier: GPL-2.0
2/*
3 * AD7170/AD7171 and AD7780/AD7781 SPI ADC driver
4 *
5 * Copyright 2011 Analog Devices Inc.
6 * Copyright 2019 Renato Lui Geh
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/gpio/consumer.h>
19#include <linux/module.h>
20#include <linux/bits.h>
21
22#include <linux/iio/iio.h>
23#include <linux/iio/sysfs.h>
24#include <linux/iio/adc/ad_sigma_delta.h>
25
26#define AD7780_RDY		BIT(7)
27#define AD7780_FILTER		BIT(6)
28#define AD7780_ERR		BIT(5)
29#define AD7780_ID1		BIT(4)
30#define AD7780_ID0		BIT(3)
31#define AD7780_GAIN		BIT(2)
32
33#define AD7170_ID		0
34#define AD7171_ID		1
35#define AD7780_ID		1
36#define AD7781_ID		0
37
38#define AD7780_ID_MASK		(AD7780_ID0 | AD7780_ID1)
39
40#define AD7780_PATTERN_GOOD	1
41#define AD7780_PATTERN_MASK	GENMASK(1, 0)
42
43#define AD7170_PATTERN_GOOD	5
44#define AD7170_PATTERN_MASK	GENMASK(2, 0)
45
46#define AD7780_GAIN_MIDPOINT	64
47#define AD7780_FILTER_MIDPOINT	13350
48
49static const unsigned int ad778x_gain[2]      = { 1, 128 };
50static const unsigned int ad778x_odr_avail[2] = { 10000, 16700 };
51
52struct ad7780_chip_info {
53	struct iio_chan_spec	channel;
54	unsigned int		pattern_mask;
55	unsigned int		pattern;
56	bool			is_ad778x;
57};
58
59struct ad7780_state {
60	const struct ad7780_chip_info	*chip_info;
61	struct regulator		*reg;
62	struct gpio_desc		*powerdown_gpio;
63	struct gpio_desc		*gain_gpio;
64	struct gpio_desc		*filter_gpio;
65	unsigned int			gain;
66	unsigned int			odr;
67	unsigned int			int_vref_mv;
68
69	struct ad_sigma_delta sd;
70};
71
72enum ad7780_supported_device_ids {
73	ID_AD7170,
74	ID_AD7171,
75	ID_AD7780,
76	ID_AD7781,
77};
78
79static struct ad7780_state *ad_sigma_delta_to_ad7780(struct ad_sigma_delta *sd)
80{
81	return container_of(sd, struct ad7780_state, sd);
82}
83
84static int ad7780_set_mode(struct ad_sigma_delta *sigma_delta,
85			   enum ad_sigma_delta_mode mode)
86{
87	struct ad7780_state *st = ad_sigma_delta_to_ad7780(sigma_delta);
88	unsigned int val;
89
90	switch (mode) {
91	case AD_SD_MODE_SINGLE:
92	case AD_SD_MODE_CONTINUOUS:
93		val = 1;
94		break;
95	default:
96		val = 0;
97		break;
98	}
99
100	gpiod_set_value(st->powerdown_gpio, val);
101
102	return 0;
103}
104
105static int ad7780_read_raw(struct iio_dev *indio_dev,
106			   struct iio_chan_spec const *chan,
107			   int *val,
108			   int *val2,
109			   long m)
110{
111	struct ad7780_state *st = iio_priv(indio_dev);
112	int voltage_uv;
113
114	switch (m) {
115	case IIO_CHAN_INFO_RAW:
116		return ad_sigma_delta_single_conversion(indio_dev, chan, val);
117	case IIO_CHAN_INFO_SCALE:
118		voltage_uv = regulator_get_voltage(st->reg);
119		if (voltage_uv < 0)
120			return voltage_uv;
121		voltage_uv /= 1000;
122		*val = voltage_uv * st->gain;
123		*val2 = chan->scan_type.realbits - 1;
124		st->int_vref_mv = voltage_uv;
125		return IIO_VAL_FRACTIONAL_LOG2;
126	case IIO_CHAN_INFO_OFFSET:
127		*val = -(1 << (chan->scan_type.realbits - 1));
128		return IIO_VAL_INT;
129	case IIO_CHAN_INFO_SAMP_FREQ:
130		*val = st->odr;
131		return IIO_VAL_INT;
132	default:
133		break;
134	}
135
136	return -EINVAL;
137}
138
139static int ad7780_write_raw(struct iio_dev *indio_dev,
140			    struct iio_chan_spec const *chan,
141			    int val,
142			    int val2,
143			    long m)
144{
145	struct ad7780_state *st = iio_priv(indio_dev);
146	const struct ad7780_chip_info *chip_info = st->chip_info;
147	unsigned long long vref;
148	unsigned int full_scale, gain;
149
150	if (!chip_info->is_ad778x)
151		return -EINVAL;
152
153	switch (m) {
154	case IIO_CHAN_INFO_SCALE:
155		if (val != 0)
156			return -EINVAL;
157
158		vref = st->int_vref_mv * 1000000LL;
159		full_scale = 1 << (chip_info->channel.scan_type.realbits - 1);
160		gain = DIV_ROUND_CLOSEST_ULL(vref, full_scale);
161		gain = DIV_ROUND_CLOSEST(gain, val2);
162		st->gain = gain;
163		if (gain < AD7780_GAIN_MIDPOINT)
164			gain = 0;
165		else
166			gain = 1;
167		gpiod_set_value(st->gain_gpio, gain);
168		break;
169	case IIO_CHAN_INFO_SAMP_FREQ:
170		if (1000*val + val2/1000 < AD7780_FILTER_MIDPOINT)
171			val = 0;
172		else
173			val = 1;
174		st->odr = ad778x_odr_avail[val];
175		gpiod_set_value(st->filter_gpio, val);
176		break;
177	default:
178		break;
179	}
180
181	return 0;
182}
183
184static int ad7780_postprocess_sample(struct ad_sigma_delta *sigma_delta,
185				     unsigned int raw_sample)
186{
187	struct ad7780_state *st = ad_sigma_delta_to_ad7780(sigma_delta);
188	const struct ad7780_chip_info *chip_info = st->chip_info;
189
190	if ((raw_sample & AD7780_ERR) ||
191	    ((raw_sample & chip_info->pattern_mask) != chip_info->pattern))
192		return -EIO;
193
194	if (chip_info->is_ad778x) {
195		st->gain = ad778x_gain[raw_sample & AD7780_GAIN];
196		st->odr = ad778x_odr_avail[raw_sample & AD7780_FILTER];
197	}
198
199	return 0;
200}
201
202static const struct ad_sigma_delta_info ad7780_sigma_delta_info = {
203	.set_mode = ad7780_set_mode,
204	.postprocess_sample = ad7780_postprocess_sample,
205	.has_registers = false,
206	.irq_flags = IRQF_TRIGGER_FALLING,
207};
208
209#define _AD7780_CHANNEL(_bits, _wordsize, _mask_all)		\
210{								\
211	.type = IIO_VOLTAGE,					\
212	.indexed = 1,						\
213	.channel = 0,						\
214	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
215		BIT(IIO_CHAN_INFO_OFFSET),			\
216	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
217	.info_mask_shared_by_all = _mask_all,			\
218	.scan_index = 1,					\
219	.scan_type = {						\
220		.sign = 'u',					\
221		.realbits = (_bits),				\
222		.storagebits = 32,				\
223		.shift = (_wordsize) - (_bits),			\
224		.endianness = IIO_BE,				\
225	},							\
226}
227
228#define AD7780_CHANNEL(_bits, _wordsize)	\
229	_AD7780_CHANNEL(_bits, _wordsize, BIT(IIO_CHAN_INFO_SAMP_FREQ))
230#define AD7170_CHANNEL(_bits, _wordsize)	\
231	_AD7780_CHANNEL(_bits, _wordsize, 0)
232
233static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
234	[ID_AD7170] = {
235		.channel = AD7170_CHANNEL(12, 24),
236		.pattern = AD7170_PATTERN_GOOD,
237		.pattern_mask = AD7170_PATTERN_MASK,
238		.is_ad778x = false,
239	},
240	[ID_AD7171] = {
241		.channel = AD7170_CHANNEL(16, 24),
242		.pattern = AD7170_PATTERN_GOOD,
243		.pattern_mask = AD7170_PATTERN_MASK,
244		.is_ad778x = false,
245	},
246	[ID_AD7780] = {
247		.channel = AD7780_CHANNEL(24, 32),
248		.pattern = AD7780_PATTERN_GOOD,
249		.pattern_mask = AD7780_PATTERN_MASK,
250		.is_ad778x = true,
251	},
252	[ID_AD7781] = {
253		.channel = AD7780_CHANNEL(20, 32),
254		.pattern = AD7780_PATTERN_GOOD,
255		.pattern_mask = AD7780_PATTERN_MASK,
256		.is_ad778x = true,
257	},
258};
259
260static const struct iio_info ad7780_info = {
261	.read_raw = ad7780_read_raw,
262	.write_raw = ad7780_write_raw,
263};
264
265static int ad7780_init_gpios(struct device *dev, struct ad7780_state *st)
266{
267	int ret;
268
269	st->powerdown_gpio = devm_gpiod_get_optional(dev,
270						     "powerdown",
271						     GPIOD_OUT_LOW);
272	if (IS_ERR(st->powerdown_gpio)) {
273		ret = PTR_ERR(st->powerdown_gpio);
274		dev_err(dev, "Failed to request powerdown GPIO: %d\n", ret);
275		return ret;
276	}
277
278	if (!st->chip_info->is_ad778x)
279		return 0;
280
281
282	st->gain_gpio = devm_gpiod_get_optional(dev,
283						"adi,gain",
284						GPIOD_OUT_HIGH);
285	if (IS_ERR(st->gain_gpio)) {
286		ret = PTR_ERR(st->gain_gpio);
287		dev_err(dev, "Failed to request gain GPIO: %d\n", ret);
288		return ret;
289	}
290
291	st->filter_gpio = devm_gpiod_get_optional(dev,
292						  "adi,filter",
293						  GPIOD_OUT_HIGH);
294	if (IS_ERR(st->filter_gpio)) {
295		ret = PTR_ERR(st->filter_gpio);
296		dev_err(dev, "Failed to request filter GPIO: %d\n", ret);
297		return ret;
298	}
299
300	return 0;
301}
302
303static void ad7780_reg_disable(void *reg)
304{
305	regulator_disable(reg);
306}
307
308static int ad7780_probe(struct spi_device *spi)
309{
310	struct ad7780_state *st;
311	struct iio_dev *indio_dev;
312	int ret;
313
314	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
315	if (!indio_dev)
316		return -ENOMEM;
317
318	st = iio_priv(indio_dev);
319	st->gain = 1;
320
321	ad_sd_init(&st->sd, indio_dev, spi, &ad7780_sigma_delta_info);
322
323	st->chip_info =
324		&ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
325
326	indio_dev->name = spi_get_device_id(spi)->name;
327	indio_dev->modes = INDIO_DIRECT_MODE;
328	indio_dev->channels = &st->chip_info->channel;
329	indio_dev->num_channels = 1;
330	indio_dev->info = &ad7780_info;
331
332	ret = ad7780_init_gpios(&spi->dev, st);
333	if (ret)
334		return ret;
335
336	st->reg = devm_regulator_get(&spi->dev, "avdd");
337	if (IS_ERR(st->reg))
338		return PTR_ERR(st->reg);
339
340	ret = regulator_enable(st->reg);
341	if (ret) {
342		dev_err(&spi->dev, "Failed to enable specified AVdd supply\n");
343		return ret;
344	}
345
346	ret = devm_add_action_or_reset(&spi->dev, ad7780_reg_disable, st->reg);
347	if (ret)
348		return ret;
349
350	ret = devm_ad_sd_setup_buffer_and_trigger(&spi->dev, indio_dev);
351	if (ret)
352		return ret;
353
354	return devm_iio_device_register(&spi->dev, indio_dev);
355}
356
357static const struct spi_device_id ad7780_id[] = {
358	{"ad7170", ID_AD7170},
359	{"ad7171", ID_AD7171},
360	{"ad7780", ID_AD7780},
361	{"ad7781", ID_AD7781},
362	{}
363};
364MODULE_DEVICE_TABLE(spi, ad7780_id);
365
366static struct spi_driver ad7780_driver = {
367	.driver = {
368		.name	= "ad7780",
369	},
370	.probe		= ad7780_probe,
371	.id_table	= ad7780_id,
372};
373module_spi_driver(ad7780_driver);
374
375MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
376MODULE_DESCRIPTION("Analog Devices AD7780 and similar ADCs");
377MODULE_LICENSE("GPL v2");
378MODULE_IMPORT_NS(IIO_AD_SIGMA_DELTA);
379