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	struct {
47		__be16 sample[2];
48		s64 timestamp;
49	} data ____cacheline_aligned;
50};
51
52static int ad7266_wakeup(struct ad7266_state *st)
53{
54	/* Any read with >= 2 bytes will wake the device */
55	return spi_read(st->spi, &st->data.sample[0], 2);
56}
57
58static int ad7266_powerdown(struct ad7266_state *st)
59{
60	/* Any read with < 2 bytes will powerdown the device */
61	return spi_read(st->spi, &st->data.sample[0], 1);
62}
63
64static int ad7266_preenable(struct iio_dev *indio_dev)
65{
66	struct ad7266_state *st = iio_priv(indio_dev);
67	return ad7266_wakeup(st);
68}
69
70static int ad7266_postdisable(struct iio_dev *indio_dev)
71{
72	struct ad7266_state *st = iio_priv(indio_dev);
73	return ad7266_powerdown(st);
74}
75
76static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
77	.preenable = &ad7266_preenable,
78	.postenable = &iio_triggered_buffer_postenable,
79	.predisable = &iio_triggered_buffer_predisable,
80	.postdisable = &ad7266_postdisable,
81};
82
83static irqreturn_t ad7266_trigger_handler(int irq, void *p)
84{
85	struct iio_poll_func *pf = p;
86	struct iio_dev *indio_dev = pf->indio_dev;
87	struct ad7266_state *st = iio_priv(indio_dev);
88	int ret;
89
90	ret = spi_read(st->spi, st->data.sample, 4);
91	if (ret == 0) {
92		iio_push_to_buffers_with_timestamp(indio_dev, &st->data,
93			    pf->timestamp);
94	}
95
96	iio_trigger_notify_done(indio_dev->trig);
97
98	return IRQ_HANDLED;
99}
100
101static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
102{
103	unsigned int i;
104
105	if (st->fixed_addr)
106		return;
107
108	switch (st->mode) {
109	case AD7266_MODE_SINGLE_ENDED:
110		nr >>= 1;
111		break;
112	case AD7266_MODE_PSEUDO_DIFF:
113		nr |= 1;
114		break;
115	case AD7266_MODE_DIFF:
116		nr &= ~1;
117		break;
118	}
119
120	for (i = 0; i < 3; ++i)
121		gpio_set_value(st->gpios[i].gpio, (bool)(nr & BIT(i)));
122}
123
124static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
125	const unsigned long *scan_mask)
126{
127	struct ad7266_state *st = iio_priv(indio_dev);
128	unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength);
129
130	ad7266_select_input(st, nr);
131
132	return 0;
133}
134
135static int ad7266_read_single(struct ad7266_state *st, int *val,
136	unsigned int address)
137{
138	int ret;
139
140	ad7266_select_input(st, address);
141
142	ret = spi_sync(st->spi, &st->single_msg);
143	*val = be16_to_cpu(st->data.sample[address % 2]);
144
145	return ret;
146}
147
148static int ad7266_read_raw(struct iio_dev *indio_dev,
149	struct iio_chan_spec const *chan, int *val, int *val2, long m)
150{
151	struct ad7266_state *st = iio_priv(indio_dev);
152	unsigned long scale_mv;
153	int ret;
154
155	switch (m) {
156	case IIO_CHAN_INFO_RAW:
157		if (iio_buffer_enabled(indio_dev))
158			return -EBUSY;
159
160		ret = ad7266_read_single(st, val, chan->address);
161		if (ret)
162			return ret;
163
164		*val = (*val >> 2) & 0xfff;
165		if (chan->scan_type.sign == 's')
166			*val = sign_extend32(*val, 11);
167
168		return IIO_VAL_INT;
169	case IIO_CHAN_INFO_SCALE:
170		scale_mv = st->vref_mv;
171		if (st->mode == AD7266_MODE_DIFF)
172			scale_mv *= 2;
173		if (st->range == AD7266_RANGE_2VREF)
174			scale_mv *= 2;
175
176		*val = scale_mv;
177		*val2 = chan->scan_type.realbits;
178		return IIO_VAL_FRACTIONAL_LOG2;
179	case IIO_CHAN_INFO_OFFSET:
180		if (st->range == AD7266_RANGE_2VREF &&
181			st->mode != AD7266_MODE_DIFF)
182			*val = 2048;
183		else
184			*val = 0;
185		return IIO_VAL_INT;
186	}
187	return -EINVAL;
188}
189
190#define AD7266_CHAN(_chan, _sign) {			\
191	.type = IIO_VOLTAGE,				\
192	.indexed = 1,					\
193	.channel = (_chan),				\
194	.address = (_chan),				\
195	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
196	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
197		| BIT(IIO_CHAN_INFO_OFFSET),			\
198	.scan_index = (_chan),				\
199	.scan_type = {					\
200		.sign = (_sign),			\
201		.realbits = 12,				\
202		.storagebits = 16,			\
203		.shift = 2,				\
204		.endianness = IIO_BE,			\
205	},						\
206}
207
208#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
209const struct iio_chan_spec ad7266_channels_##_name[] = { \
210	AD7266_CHAN(0, (_sign)), \
211	AD7266_CHAN(1, (_sign)), \
212	AD7266_CHAN(2, (_sign)), \
213	AD7266_CHAN(3, (_sign)), \
214	AD7266_CHAN(4, (_sign)), \
215	AD7266_CHAN(5, (_sign)), \
216	AD7266_CHAN(6, (_sign)), \
217	AD7266_CHAN(7, (_sign)), \
218	AD7266_CHAN(8, (_sign)), \
219	AD7266_CHAN(9, (_sign)), \
220	AD7266_CHAN(10, (_sign)), \
221	AD7266_CHAN(11, (_sign)), \
222	IIO_CHAN_SOFT_TIMESTAMP(13), \
223}
224
225#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
226const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
227	AD7266_CHAN(0, (_sign)), \
228	AD7266_CHAN(1, (_sign)), \
229	IIO_CHAN_SOFT_TIMESTAMP(2), \
230}
231
232static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
233static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
234static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
235static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');
236
237#define AD7266_CHAN_DIFF(_chan, _sign) {			\
238	.type = IIO_VOLTAGE,				\
239	.indexed = 1,					\
240	.channel = (_chan) * 2,				\
241	.channel2 = (_chan) * 2 + 1,			\
242	.address = (_chan),				\
243	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
244	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)	\
245		| BIT(IIO_CHAN_INFO_OFFSET),			\
246	.scan_index = (_chan),				\
247	.scan_type = {					\
248		.sign = _sign,			\
249		.realbits = 12,				\
250		.storagebits = 16,			\
251		.shift = 2,				\
252		.endianness = IIO_BE,			\
253	},						\
254	.differential = 1,				\
255}
256
257#define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
258const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
259	AD7266_CHAN_DIFF(0, (_sign)), \
260	AD7266_CHAN_DIFF(1, (_sign)), \
261	AD7266_CHAN_DIFF(2, (_sign)), \
262	AD7266_CHAN_DIFF(3, (_sign)), \
263	AD7266_CHAN_DIFF(4, (_sign)), \
264	AD7266_CHAN_DIFF(5, (_sign)), \
265	IIO_CHAN_SOFT_TIMESTAMP(6), \
266}
267
268static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
269static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');
270
271#define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
272const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
273	AD7266_CHAN_DIFF(0, (_sign)), \
274	AD7266_CHAN_DIFF(1, (_sign)), \
275	IIO_CHAN_SOFT_TIMESTAMP(2), \
276}
277
278static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
279static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');
280
281static const struct iio_info ad7266_info = {
282	.read_raw = &ad7266_read_raw,
283	.update_scan_mode = &ad7266_update_scan_mode,
284	.driver_module = THIS_MODULE,
285};
286
287static const unsigned long ad7266_available_scan_masks[] = {
288	0x003,
289	0x00c,
290	0x030,
291	0x0c0,
292	0x300,
293	0xc00,
294	0x000,
295};
296
297static const unsigned long ad7266_available_scan_masks_diff[] = {
298	0x003,
299	0x00c,
300	0x030,
301	0x000,
302};
303
304static const unsigned long ad7266_available_scan_masks_fixed[] = {
305	0x003,
306	0x000,
307};
308
309struct ad7266_chan_info {
310	const struct iio_chan_spec *channels;
311	unsigned int num_channels;
312	const unsigned long *scan_masks;
313};
314
315#define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
316	(((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))
317
318static const struct ad7266_chan_info ad7266_chan_infos[] = {
319	[AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
320		.channels = ad7266_channels_u,
321		.num_channels = ARRAY_SIZE(ad7266_channels_u),
322		.scan_masks = ad7266_available_scan_masks,
323	},
324	[AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
325		.channels = ad7266_channels_u_fixed,
326		.num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
327		.scan_masks = ad7266_available_scan_masks_fixed,
328	},
329	[AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
330		.channels = ad7266_channels_s,
331		.num_channels = ARRAY_SIZE(ad7266_channels_s),
332		.scan_masks = ad7266_available_scan_masks,
333	},
334	[AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
335		.channels = ad7266_channels_s_fixed,
336		.num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
337		.scan_masks = ad7266_available_scan_masks_fixed,
338	},
339	[AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
340		.channels = ad7266_channels_diff_u,
341		.num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
342		.scan_masks = ad7266_available_scan_masks_diff,
343	},
344	[AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
345		.channels = ad7266_channels_diff_fixed_u,
346		.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
347		.scan_masks = ad7266_available_scan_masks_fixed,
348	},
349	[AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
350		.channels = ad7266_channels_diff_s,
351		.num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
352		.scan_masks = ad7266_available_scan_masks_diff,
353	},
354	[AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
355		.channels = ad7266_channels_diff_fixed_s,
356		.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
357		.scan_masks = ad7266_available_scan_masks_fixed,
358	},
359};
360
361static void ad7266_init_channels(struct iio_dev *indio_dev)
362{
363	struct ad7266_state *st = iio_priv(indio_dev);
364	bool is_differential, is_signed;
365	const struct ad7266_chan_info *chan_info;
366	int i;
367
368	is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
369	is_signed = (st->range == AD7266_RANGE_2VREF) |
370		    (st->mode == AD7266_MODE_DIFF);
371
372	i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
373	chan_info = &ad7266_chan_infos[i];
374
375	indio_dev->channels = chan_info->channels;
376	indio_dev->num_channels = chan_info->num_channels;
377	indio_dev->available_scan_masks = chan_info->scan_masks;
378	indio_dev->masklength = chan_info->num_channels - 1;
379}
380
381static const char * const ad7266_gpio_labels[] = {
382	"AD0", "AD1", "AD2",
383};
384
385static int ad7266_probe(struct spi_device *spi)
386{
387	struct ad7266_platform_data *pdata = spi->dev.platform_data;
388	struct iio_dev *indio_dev;
389	struct ad7266_state *st;
390	unsigned int i;
391	int ret;
392
393	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
394	if (indio_dev == NULL)
395		return -ENOMEM;
396
397	st = iio_priv(indio_dev);
398
399	st->reg = devm_regulator_get(&spi->dev, "vref");
400	if (!IS_ERR_OR_NULL(st->reg)) {
401		ret = regulator_enable(st->reg);
402		if (ret)
403			return ret;
404
405		ret = regulator_get_voltage(st->reg);
406		if (ret < 0)
407			goto error_disable_reg;
408
409		st->vref_mv = ret / 1000;
410	} else {
411		/* Use internal reference */
412		st->vref_mv = 2500;
413	}
414
415	if (pdata) {
416		st->fixed_addr = pdata->fixed_addr;
417		st->mode = pdata->mode;
418		st->range = pdata->range;
419
420		if (!st->fixed_addr) {
421			for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
422				st->gpios[i].gpio = pdata->addr_gpios[i];
423				st->gpios[i].flags = GPIOF_OUT_INIT_LOW;
424				st->gpios[i].label = ad7266_gpio_labels[i];
425			}
426			ret = gpio_request_array(st->gpios,
427				ARRAY_SIZE(st->gpios));
428			if (ret)
429				goto error_disable_reg;
430		}
431	} else {
432		st->fixed_addr = true;
433		st->range = AD7266_RANGE_VREF;
434		st->mode = AD7266_MODE_DIFF;
435	}
436
437	spi_set_drvdata(spi, indio_dev);
438	st->spi = spi;
439
440	indio_dev->dev.parent = &spi->dev;
441	indio_dev->name = spi_get_device_id(spi)->name;
442	indio_dev->modes = INDIO_DIRECT_MODE;
443	indio_dev->info = &ad7266_info;
444
445	ad7266_init_channels(indio_dev);
446
447	/* wakeup */
448	st->single_xfer[0].rx_buf = &st->data.sample[0];
449	st->single_xfer[0].len = 2;
450	st->single_xfer[0].cs_change = 1;
451	/* conversion */
452	st->single_xfer[1].rx_buf = st->data.sample;
453	st->single_xfer[1].len = 4;
454	st->single_xfer[1].cs_change = 1;
455	/* powerdown */
456	st->single_xfer[2].tx_buf = &st->data.sample[0];
457	st->single_xfer[2].len = 1;
458
459	spi_message_init(&st->single_msg);
460	spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
461	spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
462	spi_message_add_tail(&st->single_xfer[2], &st->single_msg);
463
464	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
465		&ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
466	if (ret)
467		goto error_free_gpios;
468
469	ret = iio_device_register(indio_dev);
470	if (ret)
471		goto error_buffer_cleanup;
472
473	return 0;
474
475error_buffer_cleanup:
476	iio_triggered_buffer_cleanup(indio_dev);
477error_free_gpios:
478	if (!st->fixed_addr)
479		gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
480error_disable_reg:
481	if (!IS_ERR_OR_NULL(st->reg))
482		regulator_disable(st->reg);
483
484	return ret;
485}
486
487static int ad7266_remove(struct spi_device *spi)
488{
489	struct iio_dev *indio_dev = spi_get_drvdata(spi);
490	struct ad7266_state *st = iio_priv(indio_dev);
491
492	iio_device_unregister(indio_dev);
493	iio_triggered_buffer_cleanup(indio_dev);
494	if (!st->fixed_addr)
495		gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
496	if (!IS_ERR_OR_NULL(st->reg))
497		regulator_disable(st->reg);
498
499	return 0;
500}
501
502static const struct spi_device_id ad7266_id[] = {
503	{"ad7265", 0},
504	{"ad7266", 0},
505	{ }
506};
507MODULE_DEVICE_TABLE(spi, ad7266_id);
508
509static struct spi_driver ad7266_driver = {
510	.driver = {
511		.name	= "ad7266",
512		.owner	= THIS_MODULE,
513	},
514	.probe		= ad7266_probe,
515	.remove		= ad7266_remove,
516	.id_table	= ad7266_id,
517};
518module_spi_driver(ad7266_driver);
519
520MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
521MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
522MODULE_LICENSE("GPL v2");
523