2 * Copyright (C) 2017 Axis Communications AB
4 * Driver for Texas Instruments' ADC084S021 ADC chip.
5 * Datasheets can be found here:
6 * http://www.ti.com/lit/ds/symlink/adc084s021.pdf
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
13 #include <linux/err.h>
14 #include <linux/spi/spi.h>
15 #include <linux/module.h>
16 #include <linux/interrupt.h>
17 #include <linux/iio/iio.h>
18 #include <linux/iio/buffer.h>
19 #include <linux/iio/triggered_buffer.h>
20 #include <linux/iio/trigger_consumer.h>
21 #include <linux/regulator/consumer.h>
23 #define ADC084S021_DRIVER_NAME "adc084s021"
26 struct spi_device *spi;
27 struct spi_message message;
28 struct spi_transfer spi_trans;
29 struct regulator *reg;
31 /* Buffer used to align data */
37 * DMA (thus cache coherency maintenance) requires the
38 * transfer buffers to live in their own cache line.
40 u16 tx_buf[4] ____cacheline_aligned;
41 __be16 rx_buf[5]; /* First 16-bits are trash */
44 #define ADC084S021_VOLTAGE_CHANNEL(num) \
46 .type = IIO_VOLTAGE, \
49 .scan_index = (num), \
55 .endianness = IIO_BE, \
57 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
58 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
61 static const struct iio_chan_spec adc084s021_channels[] = {
62 ADC084S021_VOLTAGE_CHANNEL(0),
63 ADC084S021_VOLTAGE_CHANNEL(1),
64 ADC084S021_VOLTAGE_CHANNEL(2),
65 ADC084S021_VOLTAGE_CHANNEL(3),
66 IIO_CHAN_SOFT_TIMESTAMP(4),
70 * Read an ADC channel and return its value.
72 * @adc: The ADC SPI data.
73 * @data: Buffer for converted data.
75 static int adc084s021_adc_conversion(struct adc084s021 *adc, void *data)
77 int n_words = (adc->spi_trans.len >> 1) - 1; /* Discard first word */
82 ret = spi_sync(adc->spi, &adc->message);
86 for (; i < n_words; i++)
87 *(p + i) = adc->rx_buf[i + 1];
92 static int adc084s021_read_raw(struct iio_dev *indio_dev,
93 struct iio_chan_spec const *channel, int *val,
96 struct adc084s021 *adc = iio_priv(indio_dev);
100 case IIO_CHAN_INFO_RAW:
101 ret = iio_device_claim_direct_mode(indio_dev);
105 ret = regulator_enable(adc->reg);
107 iio_device_release_direct_mode(indio_dev);
111 adc->tx_buf[0] = channel->channel << 3;
112 ret = adc084s021_adc_conversion(adc, val);
113 iio_device_release_direct_mode(indio_dev);
114 regulator_disable(adc->reg);
118 *val = be16_to_cpu(*val);
119 *val = (*val >> channel->scan_type.shift) & 0xff;
122 case IIO_CHAN_INFO_SCALE:
123 ret = regulator_enable(adc->reg);
127 ret = regulator_get_voltage(adc->reg);
128 regulator_disable(adc->reg);
141 * Read enabled ADC channels and push data to the buffer.
143 * @irq: The interrupt number (not used).
144 * @pollfunc: Pointer to the poll func.
146 static irqreturn_t adc084s021_buffer_trigger_handler(int irq, void *pollfunc)
148 struct iio_poll_func *pf = pollfunc;
149 struct iio_dev *indio_dev = pf->indio_dev;
150 struct adc084s021 *adc = iio_priv(indio_dev);
152 mutex_lock(&adc->lock);
154 if (adc084s021_adc_conversion(adc, adc->scan.channels) < 0)
155 dev_err(&adc->spi->dev, "Failed to read data\n");
157 iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan,
158 iio_get_time_ns(indio_dev));
159 mutex_unlock(&adc->lock);
160 iio_trigger_notify_done(indio_dev->trig);
165 static int adc084s021_buffer_preenable(struct iio_dev *indio_dev)
167 struct adc084s021 *adc = iio_priv(indio_dev);
171 for_each_set_bit(scan_index, indio_dev->active_scan_mask,
172 indio_dev->masklength) {
173 const struct iio_chan_spec *channel =
174 &indio_dev->channels[scan_index];
175 adc->tx_buf[i++] = channel->channel << 3;
177 adc->spi_trans.len = 2 + (i * sizeof(__be16)); /* Trash + channels */
179 return regulator_enable(adc->reg);
182 static int adc084s021_buffer_postdisable(struct iio_dev *indio_dev)
184 struct adc084s021 *adc = iio_priv(indio_dev);
186 adc->spi_trans.len = 4; /* Trash + single channel */
188 return regulator_disable(adc->reg);
191 static const struct iio_info adc084s021_info = {
192 .read_raw = adc084s021_read_raw,
193 .driver_module = THIS_MODULE,
196 static const struct iio_buffer_setup_ops adc084s021_buffer_setup_ops = {
197 .preenable = adc084s021_buffer_preenable,
198 .postenable = iio_triggered_buffer_postenable,
199 .predisable = iio_triggered_buffer_predisable,
200 .postdisable = adc084s021_buffer_postdisable,
203 static int adc084s021_probe(struct spi_device *spi)
205 struct iio_dev *indio_dev;
206 struct adc084s021 *adc;
209 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
211 dev_err(&spi->dev, "Failed to allocate IIO device\n");
215 adc = iio_priv(indio_dev);
218 /* Connect the SPI device and the iio dev */
219 spi_set_drvdata(spi, indio_dev);
221 /* Initiate the Industrial I/O device */
222 indio_dev->dev.parent = &spi->dev;
223 indio_dev->dev.of_node = spi->dev.of_node;
224 indio_dev->name = spi_get_device_id(spi)->name;
225 indio_dev->modes = INDIO_DIRECT_MODE;
226 indio_dev->info = &adc084s021_info;
227 indio_dev->channels = adc084s021_channels;
228 indio_dev->num_channels = ARRAY_SIZE(adc084s021_channels);
230 /* Create SPI transfer for channel reads */
231 adc->spi_trans.tx_buf = adc->tx_buf;
232 adc->spi_trans.rx_buf = adc->rx_buf;
233 adc->spi_trans.len = 4; /* Trash + single channel */
234 spi_message_init_with_transfers(&adc->message, &adc->spi_trans, 1);
236 adc->reg = devm_regulator_get(&spi->dev, "vref");
237 if (IS_ERR(adc->reg))
238 return PTR_ERR(adc->reg);
240 mutex_init(&adc->lock);
242 /* Setup triggered buffer with pollfunction */
243 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
244 adc084s021_buffer_trigger_handler,
245 &adc084s021_buffer_setup_ops);
247 dev_err(&spi->dev, "Failed to setup triggered buffer\n");
251 return devm_iio_device_register(&spi->dev, indio_dev);
254 static const struct of_device_id adc084s021_of_match[] = {
255 { .compatible = "ti,adc084s021", },
258 MODULE_DEVICE_TABLE(of, adc084s021_of_match);
260 static const struct spi_device_id adc084s021_id[] = {
261 { ADC084S021_DRIVER_NAME, 0},
264 MODULE_DEVICE_TABLE(spi, adc084s021_id);
266 static struct spi_driver adc084s021_driver = {
268 .name = ADC084S021_DRIVER_NAME,
269 .of_match_table = of_match_ptr(adc084s021_of_match),
271 .probe = adc084s021_probe,
272 .id_table = adc084s021_id,
274 module_spi_driver(adc084s021_driver);
276 MODULE_AUTHOR("MÃ¥rten Lindahl <martenli@axis.com>");
277 MODULE_DESCRIPTION("Texas Instruments ADC084S021");
278 MODULE_LICENSE("GPL v2");
279 MODULE_VERSION("1.0");