xref: /openbmc/linux/drivers/iio/adc/ad7780.c (revision ef807729)
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 
49 static const unsigned int ad778x_gain[2]      = { 1, 128 };
50 static const unsigned int ad778x_odr_avail[2] = { 10000, 16700 };
51 
52 struct ad7780_chip_info {
53 	struct iio_chan_spec	channel;
54 	unsigned int		pattern_mask;
55 	unsigned int		pattern;
56 	bool			is_ad778x;
57 };
58 
59 struct 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 
72 enum ad7780_supported_device_ids {
73 	ID_AD7170,
74 	ID_AD7171,
75 	ID_AD7780,
76 	ID_AD7781,
77 };
78 
ad_sigma_delta_to_ad7780(struct ad_sigma_delta * sd)79 static 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 
ad7780_set_mode(struct ad_sigma_delta * sigma_delta,enum ad_sigma_delta_mode mode)84 static 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 
ad7780_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)105 static 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 
ad7780_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long m)139 static 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 
ad7780_postprocess_sample(struct ad_sigma_delta * sigma_delta,unsigned int raw_sample)184 static 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 
202 static 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 
233 static 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 
260 static const struct iio_info ad7780_info = {
261 	.read_raw = ad7780_read_raw,
262 	.write_raw = ad7780_write_raw,
263 };
264 
ad7780_init_gpios(struct device * dev,struct ad7780_state * st)265 static 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 
ad7780_reg_disable(void * reg)303 static void ad7780_reg_disable(void *reg)
304 {
305 	regulator_disable(reg);
306 }
307 
ad7780_probe(struct spi_device * spi)308 static 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 
357 static 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 };
364 MODULE_DEVICE_TABLE(spi, ad7780_id);
365 
366 static struct spi_driver ad7780_driver = {
367 	.driver = {
368 		.name	= "ad7780",
369 	},
370 	.probe		= ad7780_probe,
371 	.id_table	= ad7780_id,
372 };
373 module_spi_driver(ad7780_driver);
374 
375 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
376 MODULE_DESCRIPTION("Analog Devices AD7780 and similar ADCs");
377 MODULE_LICENSE("GPL v2");
378 MODULE_IMPORT_NS(IIO_AD_SIGMA_DELTA);
379