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 * https://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/mod_devicetable.h>
14 #include <linux/interrupt.h>
15 #include <linux/iio/iio.h>
16 #include <linux/iio/buffer.h>
17 #include <linux/iio/triggered_buffer.h>
18 #include <linux/iio/trigger_consumer.h>
19 #include <linux/regulator/consumer.h>
21 #define ADC084S021_DRIVER_NAME "adc084s021"
24 struct spi_device *spi;
25 struct spi_message message;
26 struct spi_transfer spi_trans;
27 struct regulator *reg;
29 /* Buffer used to align data */
35 * DMA (thus cache coherency maintenance) may require the
36 * transfer buffers to live in their own cache line.
38 u16 tx_buf[4] __aligned(IIO_DMA_MINALIGN);
39 __be16 rx_buf[5]; /* First 16-bits are trash */
42 #define ADC084S021_VOLTAGE_CHANNEL(num) \
44 .type = IIO_VOLTAGE, \
47 .scan_index = (num), \
53 .endianness = IIO_BE, \
55 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
56 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
59 static const struct iio_chan_spec adc084s021_channels[] = {
60 ADC084S021_VOLTAGE_CHANNEL(0),
61 ADC084S021_VOLTAGE_CHANNEL(1),
62 ADC084S021_VOLTAGE_CHANNEL(2),
63 ADC084S021_VOLTAGE_CHANNEL(3),
64 IIO_CHAN_SOFT_TIMESTAMP(4),
68 * adc084s021_adc_conversion() - Read an ADC channel and return its value.
70 * @adc: The ADC SPI data.
71 * @data: Buffer for converted data.
73 static int adc084s021_adc_conversion(struct adc084s021 *adc, __be16 *data)
75 int n_words = (adc->spi_trans.len >> 1) - 1; /* Discard first word */
79 ret = spi_sync(adc->spi, &adc->message);
83 for (; i < n_words; i++)
84 *(data + i) = adc->rx_buf[i + 1];
89 static int adc084s021_read_raw(struct iio_dev *indio_dev,
90 struct iio_chan_spec const *channel, int *val,
93 struct adc084s021 *adc = iio_priv(indio_dev);
98 case IIO_CHAN_INFO_RAW:
99 ret = iio_device_claim_direct_mode(indio_dev);
103 ret = regulator_enable(adc->reg);
105 iio_device_release_direct_mode(indio_dev);
109 adc->tx_buf[0] = channel->channel << 3;
110 ret = adc084s021_adc_conversion(adc, &be_val);
111 iio_device_release_direct_mode(indio_dev);
112 regulator_disable(adc->reg);
116 *val = be16_to_cpu(be_val);
117 *val = (*val >> channel->scan_type.shift) & 0xff;
120 case IIO_CHAN_INFO_SCALE:
121 ret = regulator_enable(adc->reg);
125 ret = regulator_get_voltage(adc->reg);
126 regulator_disable(adc->reg);
139 * adc084s021_buffer_trigger_handler() - Read ADC channels and push to buffer.
141 * @irq: The interrupt number (not used).
142 * @pollfunc: Pointer to the poll func.
144 static irqreturn_t adc084s021_buffer_trigger_handler(int irq, void *pollfunc)
146 struct iio_poll_func *pf = pollfunc;
147 struct iio_dev *indio_dev = pf->indio_dev;
148 struct adc084s021 *adc = iio_priv(indio_dev);
150 mutex_lock(&adc->lock);
152 if (adc084s021_adc_conversion(adc, adc->scan.channels) < 0)
153 dev_err(&adc->spi->dev, "Failed to read data\n");
155 iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan,
156 iio_get_time_ns(indio_dev));
157 mutex_unlock(&adc->lock);
158 iio_trigger_notify_done(indio_dev->trig);
163 static int adc084s021_buffer_preenable(struct iio_dev *indio_dev)
165 struct adc084s021 *adc = iio_priv(indio_dev);
169 for_each_set_bit(scan_index, indio_dev->active_scan_mask,
170 indio_dev->masklength) {
171 const struct iio_chan_spec *channel =
172 &indio_dev->channels[scan_index];
173 adc->tx_buf[i++] = channel->channel << 3;
175 adc->spi_trans.len = 2 + (i * sizeof(__be16)); /* Trash + channels */
177 return regulator_enable(adc->reg);
180 static int adc084s021_buffer_postdisable(struct iio_dev *indio_dev)
182 struct adc084s021 *adc = iio_priv(indio_dev);
184 adc->spi_trans.len = 4; /* Trash + single channel */
186 return regulator_disable(adc->reg);
189 static const struct iio_info adc084s021_info = {
190 .read_raw = adc084s021_read_raw,
193 static const struct iio_buffer_setup_ops adc084s021_buffer_setup_ops = {
194 .preenable = adc084s021_buffer_preenable,
195 .postdisable = adc084s021_buffer_postdisable,
198 static int adc084s021_probe(struct spi_device *spi)
200 struct iio_dev *indio_dev;
201 struct adc084s021 *adc;
204 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
206 dev_err(&spi->dev, "Failed to allocate IIO device\n");
210 adc = iio_priv(indio_dev);
213 /* Initiate the Industrial I/O device */
214 indio_dev->name = spi_get_device_id(spi)->name;
215 indio_dev->modes = INDIO_DIRECT_MODE;
216 indio_dev->info = &adc084s021_info;
217 indio_dev->channels = adc084s021_channels;
218 indio_dev->num_channels = ARRAY_SIZE(adc084s021_channels);
220 /* Create SPI transfer for channel reads */
221 adc->spi_trans.tx_buf = adc->tx_buf;
222 adc->spi_trans.rx_buf = adc->rx_buf;
223 adc->spi_trans.len = 4; /* Trash + single channel */
224 spi_message_init_with_transfers(&adc->message, &adc->spi_trans, 1);
226 adc->reg = devm_regulator_get(&spi->dev, "vref");
227 if (IS_ERR(adc->reg))
228 return PTR_ERR(adc->reg);
230 mutex_init(&adc->lock);
232 /* Setup triggered buffer with pollfunction */
233 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
234 adc084s021_buffer_trigger_handler,
235 &adc084s021_buffer_setup_ops);
237 dev_err(&spi->dev, "Failed to setup triggered buffer\n");
241 return devm_iio_device_register(&spi->dev, indio_dev);
244 static const struct of_device_id adc084s021_of_match[] = {
245 { .compatible = "ti,adc084s021", },
248 MODULE_DEVICE_TABLE(of, adc084s021_of_match);
250 static const struct spi_device_id adc084s021_id[] = {
251 { ADC084S021_DRIVER_NAME, 0 },
254 MODULE_DEVICE_TABLE(spi, adc084s021_id);
256 static struct spi_driver adc084s021_driver = {
258 .name = ADC084S021_DRIVER_NAME,
259 .of_match_table = adc084s021_of_match,
261 .probe = adc084s021_probe,
262 .id_table = adc084s021_id,
264 module_spi_driver(adc084s021_driver);
266 MODULE_AUTHOR("MÃ¥rten Lindahl <martenli@axis.com>");
267 MODULE_DESCRIPTION("Texas Instruments ADC084S021");
268 MODULE_LICENSE("GPL v2");
269 MODULE_VERSION("1.0");