1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2017 Axis Communications AB
5 * Driver for Texas Instruments' ADC084S021 ADC chip.
6 * Datasheets can be found here:
7 * http://www.ti.com/lit/ds/symlink/adc084s021.pdf
10 #include <linux/err.h>
11 #include <linux/spi/spi.h>
12 #include <linux/module.h>
13 #include <linux/interrupt.h>
14 #include <linux/iio/iio.h>
15 #include <linux/iio/buffer.h>
16 #include <linux/iio/triggered_buffer.h>
17 #include <linux/iio/trigger_consumer.h>
18 #include <linux/regulator/consumer.h>
20 #define ADC084S021_DRIVER_NAME "adc084s021"
23 struct spi_device *spi;
24 struct spi_message message;
25 struct spi_transfer spi_trans;
26 struct regulator *reg;
29 * DMA (thus cache coherency maintenance) requires the
30 * transfer buffers to live in their own cache line.
32 u16 tx_buf[4] ____cacheline_aligned;
33 __be16 rx_buf[5]; /* First 16-bits are trash */
36 #define ADC084S021_VOLTAGE_CHANNEL(num) \
38 .type = IIO_VOLTAGE, \
41 .scan_index = (num), \
47 .endianness = IIO_BE, \
49 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
50 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
53 static const struct iio_chan_spec adc084s021_channels[] = {
54 ADC084S021_VOLTAGE_CHANNEL(0),
55 ADC084S021_VOLTAGE_CHANNEL(1),
56 ADC084S021_VOLTAGE_CHANNEL(2),
57 ADC084S021_VOLTAGE_CHANNEL(3),
58 IIO_CHAN_SOFT_TIMESTAMP(4),
62 * Read an ADC channel and return its value.
64 * @adc: The ADC SPI data.
65 * @data: Buffer for converted data.
67 static int adc084s021_adc_conversion(struct adc084s021 *adc, void *data)
69 int n_words = (adc->spi_trans.len >> 1) - 1; /* Discard first word */
74 ret = spi_sync(adc->spi, &adc->message);
78 for (; i < n_words; i++)
79 *(p + i) = adc->rx_buf[i + 1];
84 static int adc084s021_read_raw(struct iio_dev *indio_dev,
85 struct iio_chan_spec const *channel, int *val,
88 struct adc084s021 *adc = iio_priv(indio_dev);
92 case IIO_CHAN_INFO_RAW:
93 ret = iio_device_claim_direct_mode(indio_dev);
97 ret = regulator_enable(adc->reg);
99 iio_device_release_direct_mode(indio_dev);
103 adc->tx_buf[0] = channel->channel << 3;
104 ret = adc084s021_adc_conversion(adc, val);
105 iio_device_release_direct_mode(indio_dev);
106 regulator_disable(adc->reg);
110 *val = be16_to_cpu(*val);
111 *val = (*val >> channel->scan_type.shift) & 0xff;
114 case IIO_CHAN_INFO_SCALE:
115 ret = regulator_enable(adc->reg);
119 ret = regulator_get_voltage(adc->reg);
120 regulator_disable(adc->reg);
133 * Read enabled ADC channels and push data to the buffer.
135 * @irq: The interrupt number (not used).
136 * @pollfunc: Pointer to the poll func.
138 static irqreturn_t adc084s021_buffer_trigger_handler(int irq, void *pollfunc)
140 struct iio_poll_func *pf = pollfunc;
141 struct iio_dev *indio_dev = pf->indio_dev;
142 struct adc084s021 *adc = iio_priv(indio_dev);
143 __be16 data[8] = {0}; /* 4 * 16-bit words of data + 8 bytes timestamp */
145 mutex_lock(&adc->lock);
147 if (adc084s021_adc_conversion(adc, &data) < 0)
148 dev_err(&adc->spi->dev, "Failed to read data\n");
150 iio_push_to_buffers_with_timestamp(indio_dev, data,
151 iio_get_time_ns(indio_dev));
152 mutex_unlock(&adc->lock);
153 iio_trigger_notify_done(indio_dev->trig);
158 static int adc084s021_buffer_preenable(struct iio_dev *indio_dev)
160 struct adc084s021 *adc = iio_priv(indio_dev);
164 for_each_set_bit(scan_index, indio_dev->active_scan_mask,
165 indio_dev->masklength) {
166 const struct iio_chan_spec *channel =
167 &indio_dev->channels[scan_index];
168 adc->tx_buf[i++] = channel->channel << 3;
170 adc->spi_trans.len = 2 + (i * sizeof(__be16)); /* Trash + channels */
172 return regulator_enable(adc->reg);
175 static int adc084s021_buffer_postdisable(struct iio_dev *indio_dev)
177 struct adc084s021 *adc = iio_priv(indio_dev);
179 adc->spi_trans.len = 4; /* Trash + single channel */
181 return regulator_disable(adc->reg);
184 static const struct iio_info adc084s021_info = {
185 .read_raw = adc084s021_read_raw,
188 static const struct iio_buffer_setup_ops adc084s021_buffer_setup_ops = {
189 .preenable = adc084s021_buffer_preenable,
190 .postenable = iio_triggered_buffer_postenable,
191 .predisable = iio_triggered_buffer_predisable,
192 .postdisable = adc084s021_buffer_postdisable,
195 static int adc084s021_probe(struct spi_device *spi)
197 struct iio_dev *indio_dev;
198 struct adc084s021 *adc;
201 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
203 dev_err(&spi->dev, "Failed to allocate IIO device\n");
207 adc = iio_priv(indio_dev);
210 /* Connect the SPI device and the iio dev */
211 spi_set_drvdata(spi, indio_dev);
213 /* Initiate the Industrial I/O device */
214 indio_dev->dev.parent = &spi->dev;
215 indio_dev->dev.of_node = spi->dev.of_node;
216 indio_dev->name = spi_get_device_id(spi)->name;
217 indio_dev->modes = INDIO_DIRECT_MODE;
218 indio_dev->info = &adc084s021_info;
219 indio_dev->channels = adc084s021_channels;
220 indio_dev->num_channels = ARRAY_SIZE(adc084s021_channels);
222 /* Create SPI transfer for channel reads */
223 adc->spi_trans.tx_buf = adc->tx_buf;
224 adc->spi_trans.rx_buf = adc->rx_buf;
225 adc->spi_trans.len = 4; /* Trash + single channel */
226 spi_message_init_with_transfers(&adc->message, &adc->spi_trans, 1);
228 adc->reg = devm_regulator_get(&spi->dev, "vref");
229 if (IS_ERR(adc->reg))
230 return PTR_ERR(adc->reg);
232 mutex_init(&adc->lock);
234 /* Setup triggered buffer with pollfunction */
235 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
236 adc084s021_buffer_trigger_handler,
237 &adc084s021_buffer_setup_ops);
239 dev_err(&spi->dev, "Failed to setup triggered buffer\n");
243 return devm_iio_device_register(&spi->dev, indio_dev);
246 static const struct of_device_id adc084s021_of_match[] = {
247 { .compatible = "ti,adc084s021", },
250 MODULE_DEVICE_TABLE(of, adc084s021_of_match);
252 static const struct spi_device_id adc084s021_id[] = {
253 { ADC084S021_DRIVER_NAME, 0},
256 MODULE_DEVICE_TABLE(spi, adc084s021_id);
258 static struct spi_driver adc084s021_driver = {
260 .name = ADC084S021_DRIVER_NAME,
261 .of_match_table = of_match_ptr(adc084s021_of_match),
263 .probe = adc084s021_probe,
264 .id_table = adc084s021_id,
266 module_spi_driver(adc084s021_driver);
268 MODULE_AUTHOR("MÃ¥rten Lindahl <martenli@axis.com>");
269 MODULE_DESCRIPTION("Texas Instruments ADC084S021");
270 MODULE_LICENSE("GPL v2");
271 MODULE_VERSION("1.0");