summaryrefslogtreecommitdiffstats
path: root/drivers/iio/adc/ad7766.c
blob: 75cca42b6e70cb548e4e4a60a3e21f4b3ba9f301 (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
/*
 * AD7766/AD7767 SPI ADC driver
 *
 * Copyright 2016 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>

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

struct ad7766_chip_info {
	unsigned int decimation_factor;
};

enum {
	AD7766_SUPPLY_AVDD = 0,
	AD7766_SUPPLY_DVDD = 1,
	AD7766_SUPPLY_VREF = 2,
	AD7766_NUM_SUPPLIES = 3
};

struct ad7766 {
	const struct ad7766_chip_info *chip_info;
	struct spi_device *spi;
	struct clk *mclk;
	struct gpio_desc *pd_gpio;
	struct regulator_bulk_data reg[AD7766_NUM_SUPPLIES];

	struct iio_trigger *trig;

	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 24 bit sample and one 64 bit
	 * aligned 64 bit timestamp.
	 */
	unsigned char data[ALIGN(3, sizeof(s64)) + sizeof(s64)]
			____cacheline_aligned;
};

/*
 * AD7766 and AD7767 variations are interface compatible, the main difference is
 * analog performance. Both parts will use the same ID.
 */
enum ad7766_device_ids {
	ID_AD7766,
	ID_AD7766_1,
	ID_AD7766_2,
};

static irqreturn_t ad7766_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct ad7766 *ad7766 = iio_priv(indio_dev);
	int ret;

	ret = spi_sync(ad7766->spi, &ad7766->msg);
	if (ret < 0)
		goto done;

	iio_push_to_buffers_with_timestamp(indio_dev, ad7766->data,
		pf->timestamp);
done:
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
}

static int ad7766_preenable(struct iio_dev *indio_dev)
{
	struct ad7766 *ad7766 = iio_priv(indio_dev);
	int ret;

	ret = regulator_bulk_enable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
	if (ret < 0) {
		dev_err(&ad7766->spi->dev, "Failed to enable supplies: %d\n",
			ret);
		return ret;
	}

	ret = clk_prepare_enable(ad7766->mclk);
	if (ret < 0) {
		dev_err(&ad7766->spi->dev, "Failed to enable MCLK: %d\n", ret);
		regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
		return ret;
	}

	if (ad7766->pd_gpio)
		gpiod_set_value(ad7766->pd_gpio, 0);

	return 0;
}

static int ad7766_postdisable(struct iio_dev *indio_dev)
{
	struct ad7766 *ad7766 = iio_priv(indio_dev);

	if (ad7766->pd_gpio)
		gpiod_set_value(ad7766->pd_gpio, 1);

	/*
	 * The PD pin is synchronous to the clock, so give it some time to
	 * notice the change before we disable the clock.
	 */
	msleep(20);

	clk_disable_unprepare(ad7766->mclk);
	regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);

	return 0;
}

static int ad7766_read_raw(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan, int *val, int *val2, long info)
{
	struct ad7766 *ad7766 = iio_priv(indio_dev);
	struct regulator *vref = ad7766->reg[AD7766_SUPPLY_VREF].consumer;
	int scale_uv;

	switch (info) {
	case IIO_CHAN_INFO_SCALE:
		scale_uv = regulator_get_voltage(vref);
		if (scale_uv < 0)
			return scale_uv;
		*val = scale_uv / 1000;
		*val2 = chan->scan_type.realbits;
		return IIO_VAL_FRACTIONAL_LOG2;
	case IIO_CHAN_INFO_SAMP_FREQ:
		*val = clk_get_rate(ad7766->mclk) /
			ad7766->chip_info->decimation_factor;
		return IIO_VAL_INT;
	}
	return -EINVAL;
}

static const struct iio_chan_spec ad7766_channels[] = {
	{
		.type = IIO_VOLTAGE,
		.indexed = 1,
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
		.scan_type = {
			.sign = 's',
			.realbits = 24,
			.storagebits = 32,
			.endianness = IIO_BE,
		},
	},
	IIO_CHAN_SOFT_TIMESTAMP(1),
};

static const struct ad7766_chip_info ad7766_chip_info[] = {
	[ID_AD7766] = {
		.decimation_factor = 8,
	},
	[ID_AD7766_1] = {
		.decimation_factor = 16,
	},
	[ID_AD7766_2] = {
		.decimation_factor = 32,
	},
};

static const struct iio_buffer_setup_ops ad7766_buffer_setup_ops = {
	.preenable = &ad7766_preenable,
	.postenable = &iio_triggered_buffer_postenable,
	.predisable = &iio_triggered_buffer_predisable,
	.postdisable = &ad7766_postdisable,
};

static const struct iio_info ad7766_info = {
	.driver_module = THIS_MODULE,
	.read_raw = &ad7766_read_raw,
};

static irqreturn_t ad7766_irq(int irq, void *private)
{
	iio_trigger_poll(private);
	return IRQ_HANDLED;
}

static int ad7766_set_trigger_state(struct iio_trigger *trig, bool enable)
{
	struct ad7766 *ad7766 = iio_trigger_get_drvdata(trig);

	if (enable)
		enable_irq(ad7766->spi->irq);
	else
		disable_irq(ad7766->spi->irq);

	return 0;
}

static const struct iio_trigger_ops ad7766_trigger_ops = {
	.owner = THIS_MODULE,
	.set_trigger_state = ad7766_set_trigger_state,
	.validate_device = iio_trigger_validate_own_device,
};

static int ad7766_probe(struct spi_device *spi)
{
	const struct spi_device_id *id = spi_get_device_id(spi);
	struct iio_dev *indio_dev;
	struct ad7766 *ad7766;
	int ret;

	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ad7766));
	if (!indio_dev)
		return -ENOMEM;

	ad7766 = iio_priv(indio_dev);
	ad7766->chip_info = &ad7766_chip_info[id->driver_data];

	ad7766->mclk = devm_clk_get(&spi->dev, "mclk");
	if (IS_ERR(ad7766->mclk))
		return PTR_ERR(ad7766->mclk);

	ad7766->reg[AD7766_SUPPLY_AVDD].supply = "avdd";
	ad7766->reg[AD7766_SUPPLY_DVDD].supply = "dvdd";
	ad7766->reg[AD7766_SUPPLY_VREF].supply = "vref";

	ret = devm_regulator_bulk_get(&spi->dev, ARRAY_SIZE(ad7766->reg),
		ad7766->reg);
	if (ret)
		return ret;

	ad7766->pd_gpio = devm_gpiod_get_optional(&spi->dev, "powerdown",
		GPIOD_OUT_HIGH);
	if (IS_ERR(ad7766->pd_gpio))
		return PTR_ERR(ad7766->pd_gpio);

	indio_dev->dev.parent = &spi->dev;
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = ad7766_channels;
	indio_dev->num_channels = ARRAY_SIZE(ad7766_channels);
	indio_dev->info = &ad7766_info;

	if (spi->irq > 0) {
		ad7766->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
			indio_dev->name, indio_dev->id);
		if (!ad7766->trig)
			return -ENOMEM;

		ad7766->trig->ops = &ad7766_trigger_ops;
		ad7766->trig->dev.parent = &spi->dev;
		iio_trigger_set_drvdata(ad7766->trig, ad7766);

		ret = devm_request_irq(&spi->dev, spi->irq, ad7766_irq,
			IRQF_TRIGGER_FALLING, dev_name(&spi->dev),
			ad7766->trig);
		if (ret < 0)
			return ret;

		/*
		 * The device generates interrupts as long as it is powered up.
		 * Some platforms might not allow the option to power it down so
		 * disable the interrupt to avoid extra load on the system
		 */
		disable_irq(spi->irq);

		ret = devm_iio_trigger_register(&spi->dev, ad7766->trig);
		if (ret)
			return ret;
	}

	spi_set_drvdata(spi, indio_dev);

	ad7766->spi = spi;

	/* First byte always 0 */
	ad7766->xfer.rx_buf = &ad7766->data[1];
	ad7766->xfer.len = 3;

	spi_message_init(&ad7766->msg);
	spi_message_add_tail(&ad7766->xfer, &ad7766->msg);

	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
		&iio_pollfunc_store_time, &ad7766_trigger_handler,
		&ad7766_buffer_setup_ops);
	if (ret)
		return ret;

	ret = devm_iio_device_register(&spi->dev, indio_dev);
	if (ret)
		return ret;
	return 0;
}

static const struct spi_device_id ad7766_id[] = {
	{"ad7766", ID_AD7766},
	{"ad7766-1", ID_AD7766_1},
	{"ad7766-2", ID_AD7766_2},
	{"ad7767", ID_AD7766},
	{"ad7767-1", ID_AD7766_1},
	{"ad7767-2", ID_AD7766_2},
	{}
};
MODULE_DEVICE_TABLE(spi, ad7766_id);

static struct spi_driver ad7766_driver = {
	.driver = {
		.name	= "ad7766",
	},
	.probe		= ad7766_probe,
	.id_table	= ad7766_id,
};
module_spi_driver(ad7766_driver);

MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Devices AD7766 and AD7767 ADCs driver support");
MODULE_LICENSE("GPL v2");