1/*
2 * AD7787/AD7788/AD7789/AD7790/AD7791 SPI ADC driver
3 *
4 * Copyright 2012 Analog Devices Inc.
5 *  Author: Lars-Peter Clausen <lars@metafoo.de>
6 *
7 * Licensed under the GPL-2.
8 */
9
10#include <linux/interrupt.h>
11#include <linux/device.h>
12#include <linux/kernel.h>
13#include <linux/slab.h>
14#include <linux/sysfs.h>
15#include <linux/spi/spi.h>
16#include <linux/regulator/consumer.h>
17#include <linux/err.h>
18#include <linux/sched.h>
19#include <linux/delay.h>
20#include <linux/module.h>
21
22#include <linux/iio/iio.h>
23#include <linux/iio/sysfs.h>
24#include <linux/iio/buffer.h>
25#include <linux/iio/trigger.h>
26#include <linux/iio/trigger_consumer.h>
27#include <linux/iio/triggered_buffer.h>
28#include <linux/iio/adc/ad_sigma_delta.h>
29
30#include <linux/platform_data/ad7791.h>
31
32#define AD7791_REG_COMM			0x0 /* For writes */
33#define AD7791_REG_STATUS		0x0 /* For reads */
34#define AD7791_REG_MODE			0x1
35#define AD7791_REG_FILTER		0x2
36#define AD7791_REG_DATA			0x3
37
38#define AD7791_MODE_CONTINUOUS		0x00
39#define AD7791_MODE_SINGLE		0x02
40#define AD7791_MODE_POWERDOWN		0x03
41
42#define AD7791_CH_AIN1P_AIN1N		0x00
43#define AD7791_CH_AIN2			0x01
44#define AD7791_CH_AIN1N_AIN1N		0x02
45#define AD7791_CH_AVDD_MONITOR		0x03
46
47#define AD7791_FILTER_CLK_DIV_1		(0x0 << 4)
48#define AD7791_FILTER_CLK_DIV_2		(0x1 << 4)
49#define AD7791_FILTER_CLK_DIV_4		(0x2 << 4)
50#define AD7791_FILTER_CLK_DIV_8		(0x3 << 4)
51#define AD7791_FILTER_CLK_MASK		(0x3 << 4)
52#define AD7791_FILTER_RATE_120		0x0
53#define AD7791_FILTER_RATE_100		0x1
54#define AD7791_FILTER_RATE_33_3		0x2
55#define AD7791_FILTER_RATE_20		0x3
56#define AD7791_FILTER_RATE_16_6		0x4
57#define AD7791_FILTER_RATE_16_7		0x5
58#define AD7791_FILTER_RATE_13_3		0x6
59#define AD7791_FILTER_RATE_9_5		0x7
60#define AD7791_FILTER_RATE_MASK		0x7
61
62#define AD7791_MODE_BUFFER		BIT(1)
63#define AD7791_MODE_UNIPOLAR		BIT(2)
64#define AD7791_MODE_BURNOUT		BIT(3)
65#define AD7791_MODE_SEL_MASK		(0x3 << 6)
66#define AD7791_MODE_SEL(x)		((x) << 6)
67
68#define DECLARE_AD7787_CHANNELS(name, bits, storagebits) \
69const struct iio_chan_spec name[] = { \
70	AD_SD_DIFF_CHANNEL(0, 0, 0, AD7791_CH_AIN1P_AIN1N, \
71		(bits), (storagebits), 0), \
72	AD_SD_CHANNEL(1, 1, AD7791_CH_AIN2, (bits), (storagebits), 0), \
73	AD_SD_SHORTED_CHANNEL(2, 0, AD7791_CH_AIN1N_AIN1N, \
74		(bits), (storagebits), 0), \
75	AD_SD_SUPPLY_CHANNEL(3, 2, AD7791_CH_AVDD_MONITOR,  \
76		(bits), (storagebits), 0), \
77	IIO_CHAN_SOFT_TIMESTAMP(4), \
78}
79
80#define DECLARE_AD7791_CHANNELS(name, bits, storagebits) \
81const struct iio_chan_spec name[] = { \
82	AD_SD_DIFF_CHANNEL(0, 0, 0, AD7791_CH_AIN1P_AIN1N, \
83		(bits), (storagebits), 0), \
84	AD_SD_SHORTED_CHANNEL(1, 0, AD7791_CH_AIN1N_AIN1N, \
85		(bits), (storagebits), 0), \
86	AD_SD_SUPPLY_CHANNEL(2, 1, AD7791_CH_AVDD_MONITOR, \
87		(bits), (storagebits), 0), \
88	IIO_CHAN_SOFT_TIMESTAMP(3), \
89}
90
91static DECLARE_AD7787_CHANNELS(ad7787_channels, 24, 32);
92static DECLARE_AD7791_CHANNELS(ad7790_channels, 16, 16);
93static DECLARE_AD7791_CHANNELS(ad7791_channels, 24, 32);
94
95enum {
96	AD7787,
97	AD7788,
98	AD7789,
99	AD7790,
100	AD7791,
101};
102
103enum ad7791_chip_info_flags {
104	AD7791_FLAG_HAS_FILTER		= (1 << 0),
105	AD7791_FLAG_HAS_BUFFER		= (1 << 1),
106	AD7791_FLAG_HAS_UNIPOLAR	= (1 << 2),
107	AD7791_FLAG_HAS_BURNOUT		= (1 << 3),
108};
109
110struct ad7791_chip_info {
111	const struct iio_chan_spec *channels;
112	unsigned int num_channels;
113	enum ad7791_chip_info_flags flags;
114};
115
116static const struct ad7791_chip_info ad7791_chip_infos[] = {
117	[AD7787] = {
118		.channels = ad7787_channels,
119		.num_channels = ARRAY_SIZE(ad7787_channels),
120		.flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
121			AD7791_FLAG_HAS_UNIPOLAR | AD7791_FLAG_HAS_BURNOUT,
122	},
123	[AD7788] = {
124		.channels = ad7790_channels,
125		.num_channels = ARRAY_SIZE(ad7790_channels),
126		.flags = AD7791_FLAG_HAS_UNIPOLAR,
127	},
128	[AD7789] = {
129		.channels = ad7791_channels,
130		.num_channels = ARRAY_SIZE(ad7791_channels),
131		.flags = AD7791_FLAG_HAS_UNIPOLAR,
132	},
133	[AD7790] = {
134		.channels = ad7790_channels,
135		.num_channels = ARRAY_SIZE(ad7790_channels),
136		.flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
137			AD7791_FLAG_HAS_BURNOUT,
138	},
139	[AD7791] = {
140		.channels = ad7791_channels,
141		.num_channels = ARRAY_SIZE(ad7791_channels),
142		.flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
143			AD7791_FLAG_HAS_UNIPOLAR | AD7791_FLAG_HAS_BURNOUT,
144	},
145};
146
147struct ad7791_state {
148	struct ad_sigma_delta sd;
149	uint8_t mode;
150	uint8_t filter;
151
152	struct regulator *reg;
153	const struct ad7791_chip_info *info;
154};
155
156static struct ad7791_state *ad_sigma_delta_to_ad7791(struct ad_sigma_delta *sd)
157{
158	return container_of(sd, struct ad7791_state, sd);
159}
160
161static int ad7791_set_channel(struct ad_sigma_delta *sd, unsigned int channel)
162{
163	ad_sd_set_comm(sd, channel);
164
165	return 0;
166}
167
168static int ad7791_set_mode(struct ad_sigma_delta *sd,
169	enum ad_sigma_delta_mode mode)
170{
171	struct ad7791_state *st = ad_sigma_delta_to_ad7791(sd);
172
173	switch (mode) {
174	case AD_SD_MODE_CONTINUOUS:
175		mode = AD7791_MODE_CONTINUOUS;
176		break;
177	case AD_SD_MODE_SINGLE:
178		mode = AD7791_MODE_SINGLE;
179		break;
180	case AD_SD_MODE_IDLE:
181	case AD_SD_MODE_POWERDOWN:
182		mode = AD7791_MODE_POWERDOWN;
183		break;
184	}
185
186	st->mode &= ~AD7791_MODE_SEL_MASK;
187	st->mode |= AD7791_MODE_SEL(mode);
188
189	return ad_sd_write_reg(sd, AD7791_REG_MODE, sizeof(st->mode), st->mode);
190}
191
192static const struct ad_sigma_delta_info ad7791_sigma_delta_info = {
193	.set_channel = ad7791_set_channel,
194	.set_mode = ad7791_set_mode,
195	.has_registers = true,
196	.addr_shift = 4,
197	.read_mask = BIT(3),
198};
199
200static int ad7791_read_raw(struct iio_dev *indio_dev,
201	const struct iio_chan_spec *chan, int *val, int *val2, long info)
202{
203	struct ad7791_state *st = iio_priv(indio_dev);
204	bool unipolar = !!(st->mode & AD7791_MODE_UNIPOLAR);
205
206	switch (info) {
207	case IIO_CHAN_INFO_RAW:
208		return ad_sigma_delta_single_conversion(indio_dev, chan, val);
209	case IIO_CHAN_INFO_OFFSET:
210		/**
211		 * Unipolar: 0 to VREF
212		 * Bipolar -VREF to VREF
213		 **/
214		if (unipolar)
215			*val = 0;
216		else
217			*val = -(1 << (chan->scan_type.realbits - 1));
218		return IIO_VAL_INT;
219	case IIO_CHAN_INFO_SCALE:
220		/* The monitor channel uses an internal reference. */
221		if (chan->address == AD7791_CH_AVDD_MONITOR) {
222			/*
223			 * The signal is attenuated by a factor of 5 and
224			 * compared against a 1.17V internal reference.
225			 */
226			*val = 1170 * 5;
227		} else {
228			int voltage_uv;
229
230			voltage_uv = regulator_get_voltage(st->reg);
231			if (voltage_uv < 0)
232				return voltage_uv;
233
234			*val = voltage_uv / 1000;
235		}
236		if (unipolar)
237			*val2 = chan->scan_type.realbits;
238		else
239			*val2 = chan->scan_type.realbits - 1;
240
241		return IIO_VAL_FRACTIONAL_LOG2;
242	}
243
244	return -EINVAL;
245}
246
247static const char * const ad7791_sample_freq_avail[] = {
248	[AD7791_FILTER_RATE_120] = "120",
249	[AD7791_FILTER_RATE_100] = "100",
250	[AD7791_FILTER_RATE_33_3] = "33.3",
251	[AD7791_FILTER_RATE_20] = "20",
252	[AD7791_FILTER_RATE_16_6] = "16.6",
253	[AD7791_FILTER_RATE_16_7] = "16.7",
254	[AD7791_FILTER_RATE_13_3] = "13.3",
255	[AD7791_FILTER_RATE_9_5] = "9.5",
256};
257
258static ssize_t ad7791_read_frequency(struct device *dev,
259	struct device_attribute *attr, char *buf)
260{
261	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
262	struct ad7791_state *st = iio_priv(indio_dev);
263	unsigned int rate = st->filter & AD7791_FILTER_RATE_MASK;
264
265	return sprintf(buf, "%s\n", ad7791_sample_freq_avail[rate]);
266}
267
268static ssize_t ad7791_write_frequency(struct device *dev,
269	struct device_attribute *attr, const char *buf, size_t len)
270{
271	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
272	struct ad7791_state *st = iio_priv(indio_dev);
273	int i, ret;
274
275	mutex_lock(&indio_dev->mlock);
276	if (iio_buffer_enabled(indio_dev)) {
277		mutex_unlock(&indio_dev->mlock);
278		return -EBUSY;
279	}
280	mutex_unlock(&indio_dev->mlock);
281
282	ret = -EINVAL;
283
284	for (i = 0; i < ARRAY_SIZE(ad7791_sample_freq_avail); i++) {
285		if (sysfs_streq(ad7791_sample_freq_avail[i], buf)) {
286
287			mutex_lock(&indio_dev->mlock);
288			st->filter &= ~AD7791_FILTER_RATE_MASK;
289			st->filter |= i;
290			ad_sd_write_reg(&st->sd, AD7791_REG_FILTER,
291					 sizeof(st->filter), st->filter);
292			mutex_unlock(&indio_dev->mlock);
293			ret = 0;
294			break;
295		}
296	}
297
298	return ret ? ret : len;
299}
300
301static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
302		ad7791_read_frequency,
303		ad7791_write_frequency);
304
305static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("120 100 33.3 20 16.7 16.6 13.3 9.5");
306
307static struct attribute *ad7791_attributes[] = {
308	&iio_dev_attr_sampling_frequency.dev_attr.attr,
309	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
310	NULL
311};
312
313static const struct attribute_group ad7791_attribute_group = {
314	.attrs = ad7791_attributes,
315};
316
317static const struct iio_info ad7791_info = {
318	.read_raw = &ad7791_read_raw,
319	.attrs = &ad7791_attribute_group,
320	.validate_trigger = ad_sd_validate_trigger,
321	.driver_module = THIS_MODULE,
322};
323
324static const struct iio_info ad7791_no_filter_info = {
325	.read_raw = &ad7791_read_raw,
326	.validate_trigger = ad_sd_validate_trigger,
327	.driver_module = THIS_MODULE,
328};
329
330static int ad7791_setup(struct ad7791_state *st,
331			struct ad7791_platform_data *pdata)
332{
333	/* Set to poweron-reset default values */
334	st->mode = AD7791_MODE_BUFFER;
335	st->filter = AD7791_FILTER_RATE_16_6;
336
337	if (!pdata)
338		return 0;
339
340	if ((st->info->flags & AD7791_FLAG_HAS_BUFFER) && !pdata->buffered)
341		st->mode &= ~AD7791_MODE_BUFFER;
342
343	if ((st->info->flags & AD7791_FLAG_HAS_BURNOUT) &&
344		pdata->burnout_current)
345		st->mode |= AD7791_MODE_BURNOUT;
346
347	if ((st->info->flags & AD7791_FLAG_HAS_UNIPOLAR) && pdata->unipolar)
348		st->mode |= AD7791_MODE_UNIPOLAR;
349
350	return ad_sd_write_reg(&st->sd, AD7791_REG_MODE, sizeof(st->mode),
351		st->mode);
352}
353
354static int ad7791_probe(struct spi_device *spi)
355{
356	struct ad7791_platform_data *pdata = spi->dev.platform_data;
357	struct iio_dev *indio_dev;
358	struct ad7791_state *st;
359	int ret;
360
361	if (!spi->irq) {
362		dev_err(&spi->dev, "Missing IRQ.\n");
363		return -ENXIO;
364	}
365
366	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
367	if (!indio_dev)
368		return -ENOMEM;
369
370	st = iio_priv(indio_dev);
371
372	st->reg = devm_regulator_get(&spi->dev, "refin");
373	if (IS_ERR(st->reg))
374		return PTR_ERR(st->reg);
375
376	ret = regulator_enable(st->reg);
377	if (ret)
378		return ret;
379
380	st->info = &ad7791_chip_infos[spi_get_device_id(spi)->driver_data];
381	ad_sd_init(&st->sd, indio_dev, spi, &ad7791_sigma_delta_info);
382
383	spi_set_drvdata(spi, indio_dev);
384
385	indio_dev->dev.parent = &spi->dev;
386	indio_dev->name = spi_get_device_id(spi)->name;
387	indio_dev->modes = INDIO_DIRECT_MODE;
388	indio_dev->channels = st->info->channels;
389	indio_dev->num_channels = st->info->num_channels;
390	if (st->info->flags & AD7791_FLAG_HAS_FILTER)
391		indio_dev->info = &ad7791_info;
392	else
393		indio_dev->info = &ad7791_no_filter_info;
394
395	ret = ad_sd_setup_buffer_and_trigger(indio_dev);
396	if (ret)
397		goto error_disable_reg;
398
399	ret = ad7791_setup(st, pdata);
400	if (ret)
401		goto error_remove_trigger;
402
403	ret = iio_device_register(indio_dev);
404	if (ret)
405		goto error_remove_trigger;
406
407	return 0;
408
409error_remove_trigger:
410	ad_sd_cleanup_buffer_and_trigger(indio_dev);
411error_disable_reg:
412	regulator_disable(st->reg);
413
414	return ret;
415}
416
417static int ad7791_remove(struct spi_device *spi)
418{
419	struct iio_dev *indio_dev = spi_get_drvdata(spi);
420	struct ad7791_state *st = iio_priv(indio_dev);
421
422	iio_device_unregister(indio_dev);
423	ad_sd_cleanup_buffer_and_trigger(indio_dev);
424
425	regulator_disable(st->reg);
426
427	return 0;
428}
429
430static const struct spi_device_id ad7791_spi_ids[] = {
431	{ "ad7787", AD7787 },
432	{ "ad7788", AD7788 },
433	{ "ad7789", AD7789 },
434	{ "ad7790", AD7790 },
435	{ "ad7791", AD7791 },
436	{}
437};
438MODULE_DEVICE_TABLE(spi, ad7791_spi_ids);
439
440static struct spi_driver ad7791_driver = {
441	.driver = {
442		.name	= "ad7791",
443		.owner	= THIS_MODULE,
444	},
445	.probe		= ad7791_probe,
446	.remove		= ad7791_remove,
447	.id_table	= ad7791_spi_ids,
448};
449module_spi_driver(ad7791_driver);
450
451MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
452MODULE_DESCRIPTION("Analog Device AD7787/AD7788/AD7789/AD7790/AD7791 ADC driver");
453MODULE_LICENSE("GPL v2");
454