summaryrefslogtreecommitdiffstats
path: root/drivers/iio/adc/ti-adc084s021.c
blob: 9017e1e24273b3bb9fae7a2442164546b2e82bae (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
// SPDX-License-Identifier: GPL-2.0-only
/**
 * Copyright (C) 2017 Axis Communications AB
 *
 * Driver for Texas Instruments' ADC084S021 ADC chip.
 * Datasheets can be found here:
 * https://www.ti.com/lit/ds/symlink/adc084s021.pdf
 */

#include <linux/err.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/interrupt.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/regulator/consumer.h>

#define ADC084S021_DRIVER_NAME "adc084s021"

struct adc084s021 {
	struct spi_device *spi;
	struct spi_message message;
	struct spi_transfer spi_trans;
	struct regulator *reg;
	struct mutex lock;
	/*
	 * DMA (thus cache coherency maintenance) requires the
	 * transfer buffers to live in their own cache line.
	 */
	u16 tx_buf[4] ____cacheline_aligned;
	__be16 rx_buf[5]; /* First 16-bits are trash */
};

#define ADC084S021_VOLTAGE_CHANNEL(num)                  \
	{                                                      \
		.type = IIO_VOLTAGE,                                 \
		.channel = (num),                                    \
		.indexed = 1,                                        \
		.scan_index = (num),                                 \
		.scan_type = {                                       \
			.sign = 'u',                                       \
			.realbits = 8,                                     \
			.storagebits = 16,                                 \
			.shift = 4,                                        \
			.endianness = IIO_BE,                              \
		},                                                   \
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),        \
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
	}

static const struct iio_chan_spec adc084s021_channels[] = {
	ADC084S021_VOLTAGE_CHANNEL(0),
	ADC084S021_VOLTAGE_CHANNEL(1),
	ADC084S021_VOLTAGE_CHANNEL(2),
	ADC084S021_VOLTAGE_CHANNEL(3),
	IIO_CHAN_SOFT_TIMESTAMP(4),
};

/**
 * Read an ADC channel and return its value.
 *
 * @adc: The ADC SPI data.
 * @data: Buffer for converted data.
 */
static int adc084s021_adc_conversion(struct adc084s021 *adc, void *data)
{
	int n_words = (adc->spi_trans.len >> 1) - 1; /* Discard first word */
	int ret, i = 0;
	u16 *p = data;

	/* Do the transfer */
	ret = spi_sync(adc->spi, &adc->message);
	if (ret < 0)
		return ret;

	for (; i < n_words; i++)
		*(p + i) = adc->rx_buf[i + 1];

	return ret;
}

static int adc084s021_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *channel, int *val,
			   int *val2, long mask)
{
	struct adc084s021 *adc = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = iio_device_claim_direct_mode(indio_dev);
		if (ret < 0)
			return ret;

		ret = regulator_enable(adc->reg);
		if (ret) {
			iio_device_release_direct_mode(indio_dev);
			return ret;
		}

		adc->tx_buf[0] = channel->channel << 3;
		ret = adc084s021_adc_conversion(adc, val);
		iio_device_release_direct_mode(indio_dev);
		regulator_disable(adc->reg);
		if (ret < 0)
			return ret;

		*val = be16_to_cpu(*val);
		*val = (*val >> channel->scan_type.shift) & 0xff;

		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		ret = regulator_enable(adc->reg);
		if (ret)
			return ret;

		ret = regulator_get_voltage(adc->reg);
		regulator_disable(adc->reg);
		if (ret < 0)
			return ret;

		*val = ret / 1000;

		return IIO_VAL_INT;
	default:
		return -EINVAL;
	}
}

/**
 * Read enabled ADC channels and push data to the buffer.
 *
 * @irq: The interrupt number (not used).
 * @pollfunc: Pointer to the poll func.
 */
static irqreturn_t adc084s021_buffer_trigger_handler(int irq, void *pollfunc)
{
	struct iio_poll_func *pf = pollfunc;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct adc084s021 *adc = iio_priv(indio_dev);
	__be16 data[8] = {0}; /* 4 * 16-bit words of data + 8 bytes timestamp */

	mutex_lock(&adc->lock);

	if (adc084s021_adc_conversion(adc, &data) < 0)
		dev_err(&adc->spi->dev, "Failed to read data\n");

	iio_push_to_buffers_with_timestamp(indio_dev, data,
					   iio_get_time_ns(indio_dev));
	mutex_unlock(&adc->lock);
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
}

static int adc084s021_buffer_preenable(struct iio_dev *indio_dev)
{
	struct adc084s021 *adc = iio_priv(indio_dev);
	int scan_index;
	int i = 0;

	for_each_set_bit(scan_index, indio_dev->active_scan_mask,
			 indio_dev->masklength) {
		const struct iio_chan_spec *channel =
			&indio_dev->channels[scan_index];
		adc->tx_buf[i++] = channel->channel << 3;
	}
	adc->spi_trans.len = 2 + (i * sizeof(__be16)); /* Trash + channels */

	return regulator_enable(adc->reg);
}

static int adc084s021_buffer_postdisable(struct iio_dev *indio_dev)
{
	struct adc084s021 *adc = iio_priv(indio_dev);

	adc->spi_trans.len = 4; /* Trash + single channel */

	return regulator_disable(adc->reg);
}

static const struct iio_info adc084s021_info = {
	.read_raw = adc084s021_read_raw,
};

static const struct iio_buffer_setup_ops adc084s021_buffer_setup_ops = {
	.preenable = adc084s021_buffer_preenable,
	.postdisable = adc084s021_buffer_postdisable,
};

static int adc084s021_probe(struct spi_device *spi)
{
	struct iio_dev *indio_dev;
	struct adc084s021 *adc;
	int ret;

	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
	if (!indio_dev) {
		dev_err(&spi->dev, "Failed to allocate IIO device\n");
		return -ENOMEM;
	}

	adc = iio_priv(indio_dev);
	adc->spi = spi;

	/* Connect the SPI device and the iio dev */
	spi_set_drvdata(spi, indio_dev);

	/* Initiate the Industrial I/O device */
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &adc084s021_info;
	indio_dev->channels = adc084s021_channels;
	indio_dev->num_channels = ARRAY_SIZE(adc084s021_channels);

	/* Create SPI transfer for channel reads */
	adc->spi_trans.tx_buf = adc->tx_buf;
	adc->spi_trans.rx_buf = adc->rx_buf;
	adc->spi_trans.len = 4; /* Trash + single channel */
	spi_message_init_with_transfers(&adc->message, &adc->spi_trans, 1);

	adc->reg = devm_regulator_get(&spi->dev, "vref");
	if (IS_ERR(adc->reg))
		return PTR_ERR(adc->reg);

	mutex_init(&adc->lock);

	/* Setup triggered buffer with pollfunction */
	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
					    adc084s021_buffer_trigger_handler,
					    &adc084s021_buffer_setup_ops);
	if (ret) {
		dev_err(&spi->dev, "Failed to setup triggered buffer\n");
		return ret;
	}

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

static const struct of_device_id adc084s021_of_match[] = {
	{ .compatible = "ti,adc084s021", },
	{},
};
MODULE_DEVICE_TABLE(of, adc084s021_of_match);

static const struct spi_device_id adc084s021_id[] = {
	{ ADC084S021_DRIVER_NAME, 0},
	{}
};
MODULE_DEVICE_TABLE(spi, adc084s021_id);

static struct spi_driver adc084s021_driver = {
	.driver = {
		.name = ADC084S021_DRIVER_NAME,
		.of_match_table = adc084s021_of_match,
	},
	.probe = adc084s021_probe,
	.id_table = adc084s021_id,
};
module_spi_driver(adc084s021_driver);

MODULE_AUTHOR("Mårten Lindahl <martenli@axis.com>");
MODULE_DESCRIPTION("Texas Instruments ADC084S021");
MODULE_LICENSE("GPL v2");
MODULE_VERSION("1.0");