summaryrefslogtreecommitdiff
path: root/drivers/iio/adc/ad7887.c
blob: 9b3cbe1ddc6f8660d52a56ad83618e90a43a6f23 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
// SPDX-License-Identifier: GPL-2.0-only
/*
 * AD7887 SPI ADC driver
 *
 * Copyright 2010-2011 Analog Devices Inc.
 */

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/spi/spi.h>
#include <linux/regulator/consumer.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/bitops.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>

#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

#include <linux/platform_data/ad7887.h>

#define AD7887_REF_DIS		BIT(5)	/* on-chip reference disable */
#define AD7887_DUAL		BIT(4)	/* dual-channel mode */
#define AD7887_CH_AIN1		BIT(3)	/* convert on channel 1, DUAL=1 */
#define AD7887_CH_AIN0		0	/* convert on channel 0, DUAL=0,1 */
#define AD7887_PM_MODE1		0	/* CS based shutdown */
#define AD7887_PM_MODE2		1	/* full on */
#define AD7887_PM_MODE3		2	/* auto shutdown after conversion */
#define AD7887_PM_MODE4		3	/* standby mode */

enum ad7887_channels {
	AD7887_CH0,
	AD7887_CH0_CH1,
	AD7887_CH1,
};

/**
 * struct ad7887_chip_info - chip specifc information
 * @int_vref_mv:	the internal reference voltage
 * @channels:		channels specification
 * @num_channels:	number of channels
 * @dual_channels:	channels specification in dual mode
 * @num_dual_channels:	number of channels in dual mode
 */
struct ad7887_chip_info {
	u16				int_vref_mv;
	const struct iio_chan_spec	*channels;
	unsigned int			num_channels;
	const struct iio_chan_spec	*dual_channels;
	unsigned int			num_dual_channels;
};

struct ad7887_state {
	struct spi_device		*spi;
	const struct ad7887_chip_info	*chip_info;
	struct regulator		*reg;
	struct spi_transfer		xfer[4];
	struct spi_message		msg[3];
	struct spi_message		*ring_msg;
	unsigned char			tx_cmd_buf[4];

	/*
	 * DMA (thus cache coherency maintenance) requires the
	 * transfer buffers to live in their own cache lines.
	 * Buffer needs to be large enough to hold two 16 bit samples and a
	 * 64 bit aligned 64 bit timestamp.
	 */
	unsigned char data[ALIGN(4, sizeof(s64)) + sizeof(s64)]
		____cacheline_aligned;
};

enum ad7887_supported_device_ids {
	ID_AD7887
};

static int ad7887_ring_preenable(struct iio_dev *indio_dev)
{
	struct ad7887_state *st = iio_priv(indio_dev);

	/* We know this is a single long so can 'cheat' */
	switch (*indio_dev->active_scan_mask) {
	case (1 << 0):
		st->ring_msg = &st->msg[AD7887_CH0];
		break;
	case (1 << 1):
		st->ring_msg = &st->msg[AD7887_CH1];
		/* Dummy read: push CH1 setting down to hardware */
		spi_sync(st->spi, st->ring_msg);
		break;
	case ((1 << 1) | (1 << 0)):
		st->ring_msg = &st->msg[AD7887_CH0_CH1];
		break;
	}

	return 0;
}

static int ad7887_ring_postdisable(struct iio_dev *indio_dev)
{
	struct ad7887_state *st = iio_priv(indio_dev);

	/* dummy read: restore default CH0 settin */
	return spi_sync(st->spi, &st->msg[AD7887_CH0]);
}

static irqreturn_t ad7887_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct ad7887_state *st = iio_priv(indio_dev);
	int b_sent;

	b_sent = spi_sync(st->spi, st->ring_msg);
	if (b_sent)
		goto done;

	iio_push_to_buffers_with_timestamp(indio_dev, st->data,
		iio_get_time_ns(indio_dev));
done:
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
}

static const struct iio_buffer_setup_ops ad7887_ring_setup_ops = {
	.preenable = &ad7887_ring_preenable,
	.postdisable = &ad7887_ring_postdisable,
};

static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
{
	int ret = spi_sync(st->spi, &st->msg[ch]);
	if (ret)
		return ret;

	return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1];
}

static int ad7887_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int *val,
			   int *val2,
			   long m)
{
	int ret;
	struct ad7887_state *st = iio_priv(indio_dev);

	switch (m) {
	case IIO_CHAN_INFO_RAW:
		ret = iio_device_claim_direct_mode(indio_dev);
		if (ret)
			return ret;
		ret = ad7887_scan_direct(st, chan->address);
		iio_device_release_direct_mode(indio_dev);

		if (ret < 0)
			return ret;
		*val = ret >> chan->scan_type.shift;
		*val &= GENMASK(chan->scan_type.realbits - 1, 0);
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		if (st->reg) {
			*val = regulator_get_voltage(st->reg);
			if (*val < 0)
				return *val;
			*val /= 1000;
		} else {
			*val = st->chip_info->int_vref_mv;
		}

		*val2 = chan->scan_type.realbits;

		return IIO_VAL_FRACTIONAL_LOG2;
	}
	return -EINVAL;
}

#define AD7887_CHANNEL(x) { \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.channel = (x), \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
	.address = (x), \
	.scan_index = (x), \
	.scan_type = { \
		.sign = 'u', \
		.realbits = 12, \
		.storagebits = 16, \
		.shift = 0, \
		.endianness = IIO_BE, \
	}, \
}

static const struct iio_chan_spec ad7887_channels[] = {
	AD7887_CHANNEL(0),
	IIO_CHAN_SOFT_TIMESTAMP(1),
};

static const struct iio_chan_spec ad7887_dual_channels[] = {
	AD7887_CHANNEL(0),
	AD7887_CHANNEL(1),
	IIO_CHAN_SOFT_TIMESTAMP(2),
};

static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
	/*
	 * More devices added in future
	 */
	[ID_AD7887] = {
		.channels = ad7887_channels,
		.num_channels = ARRAY_SIZE(ad7887_channels),
		.dual_channels = ad7887_dual_channels,
		.num_dual_channels = ARRAY_SIZE(ad7887_dual_channels),
		.int_vref_mv = 2500,
	},
};

static const struct iio_info ad7887_info = {
	.read_raw = &ad7887_read_raw,
};

static void ad7887_reg_disable(void *data)
{
	struct regulator *reg = data;

	regulator_disable(reg);
}

static int ad7887_probe(struct spi_device *spi)
{
	struct ad7887_platform_data *pdata = spi->dev.platform_data;
	struct ad7887_state *st;
	struct iio_dev *indio_dev;
	uint8_t mode;
	int ret;

	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
	if (indio_dev == NULL)
		return -ENOMEM;

	st = iio_priv(indio_dev);

	st->reg = devm_regulator_get_optional(&spi->dev, "vref");
	if (IS_ERR(st->reg)) {
		if (PTR_ERR(st->reg) != -ENODEV)
			return PTR_ERR(st->reg);

		st->reg = NULL;
	}

	if (st->reg) {
		ret = regulator_enable(st->reg);
		if (ret)
			return ret;

		ret = devm_add_action_or_reset(&spi->dev, ad7887_reg_disable, st->reg);
		if (ret)
			return ret;
	}

	st->chip_info =
		&ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];

	spi_set_drvdata(spi, indio_dev);
	st->spi = spi;

	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->info = &ad7887_info;
	indio_dev->modes = INDIO_DIRECT_MODE;

	/* Setup default message */

	mode = AD7887_PM_MODE4;
	if (!st->reg)
		mode |= AD7887_REF_DIS;
	if (pdata && pdata->en_dual)
		mode |= AD7887_DUAL;

	st->tx_cmd_buf[0] = AD7887_CH_AIN0 | mode;

	st->xfer[0].rx_buf = &st->data[0];
	st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
	st->xfer[0].len = 2;

	spi_message_init(&st->msg[AD7887_CH0]);
	spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);

	if (pdata && pdata->en_dual) {
		st->tx_cmd_buf[2] = AD7887_CH_AIN1 | mode;

		st->xfer[1].rx_buf = &st->data[0];
		st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
		st->xfer[1].len = 2;

		st->xfer[2].rx_buf = &st->data[2];
		st->xfer[2].tx_buf = &st->tx_cmd_buf[0];
		st->xfer[2].len = 2;

		spi_message_init(&st->msg[AD7887_CH0_CH1]);
		spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
		spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);

		st->xfer[3].rx_buf = &st->data[2];
		st->xfer[3].tx_buf = &st->tx_cmd_buf[2];
		st->xfer[3].len = 2;

		spi_message_init(&st->msg[AD7887_CH1]);
		spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);

		indio_dev->channels = st->chip_info->dual_channels;
		indio_dev->num_channels = st->chip_info->num_dual_channels;
	} else {
		indio_dev->channels = st->chip_info->channels;
		indio_dev->num_channels = st->chip_info->num_channels;
	}

	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
			&iio_pollfunc_store_time,
			&ad7887_trigger_handler, &ad7887_ring_setup_ops);
	if (ret)
		return ret;

	return devm_iio_device_register(&spi->dev, indio_dev);
}

static const struct spi_device_id ad7887_id[] = {
	{"ad7887", ID_AD7887},
	{}
};
MODULE_DEVICE_TABLE(spi, ad7887_id);

static struct spi_driver ad7887_driver = {
	.driver = {
		.name	= "ad7887",
	},
	.probe		= ad7887_probe,
	.id_table	= ad7887_id,
};
module_spi_driver(ad7887_driver);

MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
MODULE_LICENSE("GPL v2");