summaryrefslogtreecommitdiffstats
path: root/drivers/iio/adc/ad7476.c
blob: 1491fa6debb2c5e2cc8be063fbf3409e7b5d0b40 (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
/*
 * AD7466/7/8 AD7476/5/7/8 (A) SPI ADC driver
 *
 * Copyright 2010 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#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/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>

#define RES_MASK(bits)	((1 << (bits)) - 1)

struct ad7476_state;

struct ad7476_chip_info {
	unsigned int			int_vref_uv;
	struct iio_chan_spec		channel[2];
	void (*reset)(struct ad7476_state *);
};

struct ad7476_state {
	struct spi_device		*spi;
	const struct ad7476_chip_info	*chip_info;
	struct regulator		*reg;
	struct spi_transfer		xfer;
	struct spi_message		msg;
	/*
	 * DMA (thus cache coherency maintenance) requires the
	 * transfer buffers to live in their own cache lines.
	 * Make the buffer large enough for one 16 bit sample and one 64 bit
	 * aligned 64 bit timestamp.
	 */
	unsigned char data[ALIGN(2, sizeof(s64)) + sizeof(s64)]
			____cacheline_aligned;
};

enum ad7476_supported_device_ids {
	ID_AD7091R,
	ID_AD7276,
	ID_AD7277,
	ID_AD7278,
	ID_AD7466,
	ID_AD7467,
	ID_AD7468,
	ID_AD7495,
	ID_AD7940,
};

static irqreturn_t ad7476_trigger_handler(int irq, void  *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct ad7476_state *st = iio_priv(indio_dev);
	s64 time_ns;
	int b_sent;

	b_sent = spi_sync(st->spi, &st->msg);
	if (b_sent < 0)
		goto done;

	time_ns = iio_get_time_ns();

	if (indio_dev->scan_timestamp)
		((s64 *)st->data)[1] = time_ns;

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

	return IRQ_HANDLED;
}

static void ad7091_reset(struct ad7476_state *st)
{
	/* Any transfers with 8 scl cycles will reset the device */
	spi_read(st->spi, st->data, 1);
}

static int ad7476_scan_direct(struct ad7476_state *st)
{
	int ret;

	ret = spi_sync(st->spi, &st->msg);
	if (ret)
		return ret;

	return be16_to_cpup((__be16 *)st->data);
}

static int ad7476_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int *val,
			   int *val2,
			   long m)
{
	int ret;
	struct ad7476_state *st = iio_priv(indio_dev);
	int scale_uv;

	switch (m) {
	case IIO_CHAN_INFO_RAW:
		mutex_lock(&indio_dev->mlock);
		if (iio_buffer_enabled(indio_dev))
			ret = -EBUSY;
		else
			ret = ad7476_scan_direct(st);
		mutex_unlock(&indio_dev->mlock);

		if (ret < 0)
			return ret;
		*val = (ret >> st->chip_info->channel[0].scan_type.shift) &
			RES_MASK(st->chip_info->channel[0].scan_type.realbits);
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		if (!st->chip_info->int_vref_uv) {
			scale_uv = regulator_get_voltage(st->reg);
			if (scale_uv < 0)
				return scale_uv;
		} else {
			scale_uv = st->chip_info->int_vref_uv;
		}
		scale_uv >>= chan->scan_type.realbits;
		*val =  scale_uv / 1000;
		*val2 = (scale_uv % 1000) * 1000;
		return IIO_VAL_INT_PLUS_MICRO;
	}
	return -EINVAL;
}

#define _AD7476_CHAN(bits, _shift, _info_mask)			\
	{							\
	.type = IIO_VOLTAGE,					\
	.indexed = 1,						\
	.info_mask = _info_mask |				\
	IIO_CHAN_INFO_SCALE_SHARED_BIT,				\
	.scan_type = {						\
		.sign = 'u',					\
		.realbits = (bits),				\
		.storagebits = 16,				\
		.shift = (_shift),				\
		.endianness = IIO_BE,				\
	},							\
}

#define AD7476_CHAN(bits) _AD7476_CHAN((bits), 13 - (bits), \
		IIO_CHAN_INFO_RAW_SEPARATE_BIT)
#define AD7940_CHAN(bits) _AD7476_CHAN((bits), 15 - (bits), \
		IIO_CHAN_INFO_RAW_SEPARATE_BIT)
#define AD7091R_CHAN(bits) _AD7476_CHAN((bits), 16 - (bits), 0)

static const struct ad7476_chip_info ad7476_chip_info_tbl[] = {
	[ID_AD7091R] = {
		.channel[0] = AD7091R_CHAN(12),
		.channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
		.reset = ad7091_reset,
	},
	[ID_AD7276] = {
		.channel[0] = AD7940_CHAN(12),
		.channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
	},
	[ID_AD7277] = {
		.channel[0] = AD7940_CHAN(10),
		.channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
	},
	[ID_AD7278] = {
		.channel[0] = AD7940_CHAN(8),
		.channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
	},
	[ID_AD7466] = {
		.channel[0] = AD7476_CHAN(12),
		.channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
	},
	[ID_AD7467] = {
		.channel[0] = AD7476_CHAN(10),
		.channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
	},
	[ID_AD7468] = {
		.channel[0] = AD7476_CHAN(8),
		.channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
	},
	[ID_AD7495] = {
		.channel[0] = AD7476_CHAN(12),
		.channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
		.int_vref_uv = 2500000,
	},
	[ID_AD7940] = {
		.channel[0] = AD7940_CHAN(14),
		.channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
	},
};

static const struct iio_info ad7476_info = {
	.driver_module = THIS_MODULE,
	.read_raw = &ad7476_read_raw,
};

static int ad7476_probe(struct spi_device *spi)
{
	struct ad7476_state *st;
	struct iio_dev *indio_dev;
	int ret;

	indio_dev = iio_device_alloc(sizeof(*st));
	if (indio_dev == NULL) {
		ret = -ENOMEM;
		goto error_ret;
	}
	st = iio_priv(indio_dev);
	st->chip_info =
		&ad7476_chip_info_tbl[spi_get_device_id(spi)->driver_data];

	st->reg = regulator_get(&spi->dev, "vcc");
	if (IS_ERR(st->reg)) {
		ret = PTR_ERR(st->reg);
		goto error_free_dev;
	}

	ret = regulator_enable(st->reg);
	if (ret)
		goto error_put_reg;

	spi_set_drvdata(spi, indio_dev);

	st->spi = spi;

	/* Establish that the iio_dev is a child of the spi device */
	indio_dev->dev.parent = &spi->dev;
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = st->chip_info->channel;
	indio_dev->num_channels = 2;
	indio_dev->info = &ad7476_info;
	/* Setup default message */

	st->xfer.rx_buf = &st->data;
	st->xfer.len = st->chip_info->channel[0].scan_type.storagebits / 8;

	spi_message_init(&st->msg);
	spi_message_add_tail(&st->xfer, &st->msg);

	ret = iio_triggered_buffer_setup(indio_dev, NULL,
			&ad7476_trigger_handler, NULL);
	if (ret)
		goto error_disable_reg;

	if (st->chip_info->reset)
		st->chip_info->reset(st);

	ret = iio_device_register(indio_dev);
	if (ret)
		goto error_ring_unregister;
	return 0;

error_ring_unregister:
	iio_triggered_buffer_cleanup(indio_dev);
error_disable_reg:
	regulator_disable(st->reg);
error_put_reg:
	regulator_put(st->reg);
error_free_dev:
	iio_device_free(indio_dev);

error_ret:
	return ret;
}

static int ad7476_remove(struct spi_device *spi)
{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct ad7476_state *st = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	iio_triggered_buffer_cleanup(indio_dev);
	regulator_disable(st->reg);
	regulator_put(st->reg);
	iio_device_free(indio_dev);

	return 0;
}

static const struct spi_device_id ad7476_id[] = {
	{"ad7091r", ID_AD7091R},
	{"ad7273", ID_AD7277},
	{"ad7274", ID_AD7276},
	{"ad7276", ID_AD7276},
	{"ad7277", ID_AD7277},
	{"ad7278", ID_AD7278},
	{"ad7466", ID_AD7466},
	{"ad7467", ID_AD7467},
	{"ad7468", ID_AD7468},
	{"ad7475", ID_AD7466},
	{"ad7476", ID_AD7466},
	{"ad7476a", ID_AD7466},
	{"ad7477", ID_AD7467},
	{"ad7477a", ID_AD7467},
	{"ad7478", ID_AD7468},
	{"ad7478a", ID_AD7468},
	{"ad7495", ID_AD7495},
	{"ad7910", ID_AD7467},
	{"ad7920", ID_AD7466},
	{"ad7940", ID_AD7940},
	{}
};
MODULE_DEVICE_TABLE(spi, ad7476_id);

static struct spi_driver ad7476_driver = {
	.driver = {
		.name	= "ad7476",
		.owner	= THIS_MODULE,
	},
	.probe		= ad7476_probe,
	.remove		= ad7476_remove,
	.id_table	= ad7476_id,
};
module_spi_driver(ad7476_driver);

MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("Analog Devices AD7476 and similar 1-channel ADCs");
MODULE_LICENSE("GPL v2");
OpenPOWER on IntegriCloud