ad7266.c revision 06e1b542bb06a84bb536d9865c6547422cc240b5 
1/*
2 * AD7266/65 SPI ADC driver
3 *
4 * Copyright 2012 Analog Devices Inc.
5 *
6 * Licensed under the GPL-2.
7 */
8
9#include <linux/device.h>
10#include <linux/kernel.h>
11#include <linux/slab.h>
12#include <linux/spi/spi.h>
13#include <linux/regulator/consumer.h>
14#include <linux/err.h>
15#include <linux/gpio.h>
16#include <linux/module.h>
17
18#include <linux/interrupt.h>
19
20#include <linux/iio/iio.h>
21#include <linux/iio/buffer.h>
22#include <linux/iio/trigger_consumer.h>
23#include <linux/iio/triggered_buffer.h>
24
25#include <linux/platform_data/ad7266.h>
26
27struct ad7266_state {
28	struct spi_device	*spi;
29	struct regulator	*reg;
30	unsigned long		vref_mv;
31
32	struct spi_transfer	single_xfer[3];
33	struct spi_message	single_msg;
34
35	enum ad7266_range	range;
36	enum ad7266_mode	mode;
37	bool			fixed_addr;
38	struct gpio		gpios[3];
39
40	/*
41	 * DMA (thus cache coherency maintenance) requires the
42	 * transfer buffers to live in their own cache lines.
43	 * The buffer needs to be large enough to hold two samples (4 bytes) and
44	 * the naturally aligned timestamp (8 bytes).
45	 */
46	uint8_t data[ALIGN(4, sizeof(s64)) + sizeof(s64)] ____cacheline_aligned;
47};
48
49static int ad7266_wakeup(struct ad7266_state *st)
50{
51	/* Any read with >= 2 bytes will wake the device */
52	return spi_read(st->spi, st->data, 2);
53}
54
55static int ad7266_powerdown(struct ad7266_state *st)
56{
57	/* Any read with < 2 bytes will powerdown the device */
58	return spi_read(st->spi, st->data, 1);
59}
60
61static int ad7266_preenable(struct iio_dev *indio_dev)
62{
63	struct ad7266_state *st = iio_priv(indio_dev);
64	return ad7266_wakeup(st);
65}
66
67static int ad7266_postdisable(struct iio_dev *indio_dev)
68{
69	struct ad7266_state *st = iio_priv(indio_dev);
70	return ad7266_powerdown(st);
71}
72
73static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
74	.preenable = &ad7266_preenable,
75	.postenable = &iio_triggered_buffer_postenable,
76	.predisable = &iio_triggered_buffer_predisable,
77	.postdisable = &ad7266_postdisable,
78};
79
80static irqreturn_t ad7266_trigger_handler(int irq, void *p)
81{
82	struct iio_poll_func *pf = p;
83	struct iio_dev *indio_dev = pf->indio_dev;
84	struct ad7266_state *st = iio_priv(indio_dev);
85	int ret;
86
87	ret = spi_read(st->spi, st->data, 4);
88	if (ret == 0) {
89		iio_push_to_buffers_with_timestamp(indio_dev, st->data,
90			    pf->timestamp);
91	}
92
93	iio_trigger_notify_done(indio_dev->trig);
94
95	return IRQ_HANDLED;
96}
97
98static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
99{
100	unsigned int i;
101
102	if (st->fixed_addr)
103		return;
104
105	switch (st->mode) {
106	case AD7266_MODE_SINGLE_ENDED:
107		nr >>= 1;
108		break;
109	case AD7266_MODE_PSEUDO_DIFF:
110		nr |= 1;
111		break;
112	case AD7266_MODE_DIFF:
113		nr &= ~1;
114		break;
115	}
116
117	for (i = 0; i < 3; ++i)
118		gpio_set_value(st->gpios[i].gpio, (bool)(nr & BIT(i)));
119}
120
121static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
122	const unsigned long *scan_mask)
123{
124	struct ad7266_state *st = iio_priv(indio_dev);
125	unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength);
126
127	ad7266_select_input(st, nr);
128
129	return 0;
130}
131
132static int ad7266_read_single(struct ad7266_state *st, int *val,
133	unsigned int address)
134{
135	int ret;
136
137	ad7266_select_input(st, address);
138
139	ret = spi_sync(st->spi, &st->single_msg);
140	*val = be16_to_cpu(st->data[address % 2]);
141
142	return ret;
143}
144
145static int ad7266_read_raw(struct iio_dev *indio_dev,
146	struct iio_chan_spec const *chan, int *val, int *val2, long m)
147{
148	struct ad7266_state *st = iio_priv(indio_dev);
149	unsigned long scale_mv;
150	int ret;
151
152	switch (m) {
153	case IIO_CHAN_INFO_RAW:
154		if (iio_buffer_enabled(indio_dev))
155			return -EBUSY;
156
157		ret = ad7266_read_single(st, val, chan->address);
158		if (ret)
159			return ret;
160
161		*val = (*val >> 2) & 0xfff;
162		if (chan->scan_type.sign == 's')
163			*val = sign_extend32(*val, 11);
164
165		return IIO_VAL_INT;
166	case IIO_CHAN_INFO_SCALE:
167		scale_mv = st->vref_mv;
168		if (st->mode == AD7266_MODE_DIFF)
169			scale_mv *= 2;
170		if (st->range == AD7266_RANGE_2VREF)
171			scale_mv *= 2;
172
173		*val = scale_mv;
174		*val2 = chan->scan_type.realbits;
175		return IIO_VAL_FRACTIONAL_LOG2;
176	case IIO_CHAN_INFO_OFFSET:
177		if (st->range == AD7266_RANGE_2VREF &&
178			st->mode != AD7266_MODE_DIFF)
179			*val = 2048;
180		else
181			*val = 0;
182		return IIO_VAL_INT;
183	}
184	return -EINVAL;
185}
186
187#define AD7266_CHAN(_chan, _sign) {			\
188	.type = IIO_VOLTAGE,				\
189	.indexed = 1,					\
190	.channel = (_chan),				\
191	.address = (_chan),				\
192	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
193	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
194		| BIT(IIO_CHAN_INFO_OFFSET),			\
195	.scan_index = (_chan),				\
196	.scan_type = {					\
197		.sign = (_sign),			\
198		.realbits = 12,				\
199		.storagebits = 16,			\
200		.shift = 2,				\
201		.endianness = IIO_BE,			\
202	},						\
203}
204
205#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
206const struct iio_chan_spec ad7266_channels_##_name[] = { \
207	AD7266_CHAN(0, (_sign)), \
208	AD7266_CHAN(1, (_sign)), \
209	AD7266_CHAN(2, (_sign)), \
210	AD7266_CHAN(3, (_sign)), \
211	AD7266_CHAN(4, (_sign)), \
212	AD7266_CHAN(5, (_sign)), \
213	AD7266_CHAN(6, (_sign)), \
214	AD7266_CHAN(7, (_sign)), \
215	AD7266_CHAN(8, (_sign)), \
216	AD7266_CHAN(9, (_sign)), \
217	AD7266_CHAN(10, (_sign)), \
218	AD7266_CHAN(11, (_sign)), \
219	IIO_CHAN_SOFT_TIMESTAMP(13), \
220}
221
222#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
223const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
224	AD7266_CHAN(0, (_sign)), \
225	AD7266_CHAN(1, (_sign)), \
226	IIO_CHAN_SOFT_TIMESTAMP(2), \
227}
228
229static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
230static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
231static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
232static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');
233
234#define AD7266_CHAN_DIFF(_chan, _sign) {			\
235	.type = IIO_VOLTAGE,				\
236	.indexed = 1,					\
237	.channel = (_chan) * 2,				\
238	.channel2 = (_chan) * 2 + 1,			\
239	.address = (_chan),				\
240	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
241	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)	\
242		| BIT(IIO_CHAN_INFO_OFFSET),			\
243	.scan_index = (_chan),				\
244	.scan_type = {					\
245		.sign = _sign,			\
246		.realbits = 12,				\
247		.storagebits = 16,			\
248		.shift = 2,				\
249		.endianness = IIO_BE,			\
250	},						\
251	.differential = 1,				\
252}
253
254#define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
255const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
256	AD7266_CHAN_DIFF(0, (_sign)), \
257	AD7266_CHAN_DIFF(1, (_sign)), \
258	AD7266_CHAN_DIFF(2, (_sign)), \
259	AD7266_CHAN_DIFF(3, (_sign)), \
260	AD7266_CHAN_DIFF(4, (_sign)), \
261	AD7266_CHAN_DIFF(5, (_sign)), \
262	IIO_CHAN_SOFT_TIMESTAMP(6), \
263}
264
265static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
266static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');
267
268#define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
269const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
270	AD7266_CHAN_DIFF(0, (_sign)), \
271	AD7266_CHAN_DIFF(1, (_sign)), \
272	IIO_CHAN_SOFT_TIMESTAMP(2), \
273}
274
275static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
276static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');
277
278static const struct iio_info ad7266_info = {
279	.read_raw = &ad7266_read_raw,
280	.update_scan_mode = &ad7266_update_scan_mode,
281	.driver_module = THIS_MODULE,
282};
283
284static const unsigned long ad7266_available_scan_masks[] = {
285	0x003,
286	0x00c,
287	0x030,
288	0x0c0,
289	0x300,
290	0xc00,
291	0x000,
292};
293
294static const unsigned long ad7266_available_scan_masks_diff[] = {
295	0x003,
296	0x00c,
297	0x030,
298	0x000,
299};
300
301static const unsigned long ad7266_available_scan_masks_fixed[] = {
302	0x003,
303	0x000,
304};
305
306struct ad7266_chan_info {
307	const struct iio_chan_spec *channels;
308	unsigned int num_channels;
309	const unsigned long *scan_masks;
310};
311
312#define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
313	(((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))
314
315static const struct ad7266_chan_info ad7266_chan_infos[] = {
316	[AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
317		.channels = ad7266_channels_u,
318		.num_channels = ARRAY_SIZE(ad7266_channels_u),
319		.scan_masks = ad7266_available_scan_masks,
320	},
321	[AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
322		.channels = ad7266_channels_u_fixed,
323		.num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
324		.scan_masks = ad7266_available_scan_masks_fixed,
325	},
326	[AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
327		.channels = ad7266_channels_s,
328		.num_channels = ARRAY_SIZE(ad7266_channels_s),
329		.scan_masks = ad7266_available_scan_masks,
330	},
331	[AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
332		.channels = ad7266_channels_s_fixed,
333		.num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
334		.scan_masks = ad7266_available_scan_masks_fixed,
335	},
336	[AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
337		.channels = ad7266_channels_diff_u,
338		.num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
339		.scan_masks = ad7266_available_scan_masks_diff,
340	},
341	[AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
342		.channels = ad7266_channels_diff_fixed_u,
343		.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
344		.scan_masks = ad7266_available_scan_masks_fixed,
345	},
346	[AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
347		.channels = ad7266_channels_diff_s,
348		.num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
349		.scan_masks = ad7266_available_scan_masks_diff,
350	},
351	[AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
352		.channels = ad7266_channels_diff_fixed_s,
353		.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
354		.scan_masks = ad7266_available_scan_masks_fixed,
355	},
356};
357
358static void ad7266_init_channels(struct iio_dev *indio_dev)
359{
360	struct ad7266_state *st = iio_priv(indio_dev);
361	bool is_differential, is_signed;
362	const struct ad7266_chan_info *chan_info;
363	int i;
364
365	is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
366	is_signed = (st->range == AD7266_RANGE_2VREF) |
367		    (st->mode == AD7266_MODE_DIFF);
368
369	i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
370	chan_info = &ad7266_chan_infos[i];
371
372	indio_dev->channels = chan_info->channels;
373	indio_dev->num_channels = chan_info->num_channels;
374	indio_dev->available_scan_masks = chan_info->scan_masks;
375	indio_dev->masklength = chan_info->num_channels - 1;
376}
377
378static const char * const ad7266_gpio_labels[] = {
379	"AD0", "AD1", "AD2",
380};
381
382static int ad7266_probe(struct spi_device *spi)
383{
384	struct ad7266_platform_data *pdata = spi->dev.platform_data;
385	struct iio_dev *indio_dev;
386	struct ad7266_state *st;
387	unsigned int i;
388	int ret;
389
390	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
391	if (indio_dev == NULL)
392		return -ENOMEM;
393
394	st = iio_priv(indio_dev);
395
396	st->reg = devm_regulator_get(&spi->dev, "vref");
397	if (!IS_ERR_OR_NULL(st->reg)) {
398		ret = regulator_enable(st->reg);
399		if (ret)
400			return ret;
401
402		ret = regulator_get_voltage(st->reg);
403		if (ret < 0)
404			goto error_disable_reg;
405
406		st->vref_mv = ret / 1000;
407	} else {
408		/* Use internal reference */
409		st->vref_mv = 2500;
410	}
411
412	if (pdata) {
413		st->fixed_addr = pdata->fixed_addr;
414		st->mode = pdata->mode;
415		st->range = pdata->range;
416
417		if (!st->fixed_addr) {
418			for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
419				st->gpios[i].gpio = pdata->addr_gpios[i];
420				st->gpios[i].flags = GPIOF_OUT_INIT_LOW;
421				st->gpios[i].label = ad7266_gpio_labels[i];
422			}
423			ret = gpio_request_array(st->gpios,
424				ARRAY_SIZE(st->gpios));
425			if (ret)
426				goto error_disable_reg;
427		}
428	} else {
429		st->fixed_addr = true;
430		st->range = AD7266_RANGE_VREF;
431		st->mode = AD7266_MODE_DIFF;
432	}
433
434	spi_set_drvdata(spi, indio_dev);
435	st->spi = spi;
436
437	indio_dev->dev.parent = &spi->dev;
438	indio_dev->name = spi_get_device_id(spi)->name;
439	indio_dev->modes = INDIO_DIRECT_MODE;
440	indio_dev->info = &ad7266_info;
441
442	ad7266_init_channels(indio_dev);
443
444	/* wakeup */
445	st->single_xfer[0].rx_buf = &st->data;
446	st->single_xfer[0].len = 2;
447	st->single_xfer[0].cs_change = 1;
448	/* conversion */
449	st->single_xfer[1].rx_buf = &st->data;
450	st->single_xfer[1].len = 4;
451	st->single_xfer[1].cs_change = 1;
452	/* powerdown */
453	st->single_xfer[2].tx_buf = &st->data;
454	st->single_xfer[2].len = 1;
455
456	spi_message_init(&st->single_msg);
457	spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
458	spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
459	spi_message_add_tail(&st->single_xfer[2], &st->single_msg);
460
461	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
462		&ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
463	if (ret)
464		goto error_free_gpios;
465
466	ret = iio_device_register(indio_dev);
467	if (ret)
468		goto error_buffer_cleanup;
469
470	return 0;
471
472error_buffer_cleanup:
473	iio_triggered_buffer_cleanup(indio_dev);
474error_free_gpios:
475	if (!st->fixed_addr)
476		gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
477error_disable_reg:
478	if (!IS_ERR_OR_NULL(st->reg))
479		regulator_disable(st->reg);
480
481	return ret;
482}
483
484static int ad7266_remove(struct spi_device *spi)
485{
486	struct iio_dev *indio_dev = spi_get_drvdata(spi);
487	struct ad7266_state *st = iio_priv(indio_dev);
488
489	iio_device_unregister(indio_dev);
490	iio_triggered_buffer_cleanup(indio_dev);
491	if (!st->fixed_addr)
492		gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
493	if (!IS_ERR_OR_NULL(st->reg))
494		regulator_disable(st->reg);
495
496	return 0;
497}
498
499static const struct spi_device_id ad7266_id[] = {
500	{"ad7265", 0},
501	{"ad7266", 0},
502	{ }
503};
504MODULE_DEVICE_TABLE(spi, ad7266_id);
505
506static struct spi_driver ad7266_driver = {
507	.driver = {
508		.name	= "ad7266",
509		.owner	= THIS_MODULE,
510	},
511	.probe		= ad7266_probe,
512	.remove		= ad7266_remove,
513	.id_table	= ad7266_id,
514};
515module_spi_driver(ad7266_driver);
516
517MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
518MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
519MODULE_LICENSE("GPL v2");
520