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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * ADC0831/ADC0832/ADC0834/ADC0838 8-bit ADC driver4 *5 * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>6 *7 * Datasheet: https://www.ti.com/lit/ds/symlink/adc0832-n.pdf8 */9 10#include <linux/module.h>11#include <linux/mod_devicetable.h>12#include <linux/spi/spi.h>13#include <linux/iio/iio.h>14#include <linux/regulator/consumer.h>15#include <linux/iio/buffer.h>16#include <linux/iio/trigger.h>17#include <linux/iio/triggered_buffer.h>18#include <linux/iio/trigger_consumer.h>19 20enum {21 adc0831,22 adc0832,23 adc0834,24 adc0838,25};26 27struct adc0832 {28 struct spi_device *spi;29 struct regulator *reg;30 struct mutex lock;31 u8 mux_bits;32 /*33 * Max size needed: 16x 1 byte ADC data + 8 bytes timestamp34 * May be shorter if not all channels are enabled subject35 * to the timestamp remaining 8 byte aligned.36 */37 u8 data[24] __aligned(8);38 39 u8 tx_buf[2] __aligned(IIO_DMA_MINALIGN);40 u8 rx_buf[2];41};42 43#define ADC0832_VOLTAGE_CHANNEL(chan) \44 { \45 .type = IIO_VOLTAGE, \46 .indexed = 1, \47 .channel = chan, \48 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \49 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \50 .scan_index = chan, \51 .scan_type = { \52 .sign = 'u', \53 .realbits = 8, \54 .storagebits = 8, \55 }, \56 }57 58#define ADC0832_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si) \59 { \60 .type = IIO_VOLTAGE, \61 .indexed = 1, \62 .channel = (chan1), \63 .channel2 = (chan2), \64 .differential = 1, \65 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \66 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \67 .scan_index = si, \68 .scan_type = { \69 .sign = 'u', \70 .realbits = 8, \71 .storagebits = 8, \72 }, \73 }74 75static const struct iio_chan_spec adc0831_channels[] = {76 ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 0),77 IIO_CHAN_SOFT_TIMESTAMP(1),78};79 80static const struct iio_chan_spec adc0832_channels[] = {81 ADC0832_VOLTAGE_CHANNEL(0),82 ADC0832_VOLTAGE_CHANNEL(1),83 ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 2),84 ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 3),85 IIO_CHAN_SOFT_TIMESTAMP(4),86};87 88static const struct iio_chan_spec adc0834_channels[] = {89 ADC0832_VOLTAGE_CHANNEL(0),90 ADC0832_VOLTAGE_CHANNEL(1),91 ADC0832_VOLTAGE_CHANNEL(2),92 ADC0832_VOLTAGE_CHANNEL(3),93 ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 4),94 ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 5),95 ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 6),96 ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 7),97 IIO_CHAN_SOFT_TIMESTAMP(8),98};99 100static const struct iio_chan_spec adc0838_channels[] = {101 ADC0832_VOLTAGE_CHANNEL(0),102 ADC0832_VOLTAGE_CHANNEL(1),103 ADC0832_VOLTAGE_CHANNEL(2),104 ADC0832_VOLTAGE_CHANNEL(3),105 ADC0832_VOLTAGE_CHANNEL(4),106 ADC0832_VOLTAGE_CHANNEL(5),107 ADC0832_VOLTAGE_CHANNEL(6),108 ADC0832_VOLTAGE_CHANNEL(7),109 ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 8),110 ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 9),111 ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 10),112 ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 11),113 ADC0832_VOLTAGE_CHANNEL_DIFF(4, 5, 12),114 ADC0832_VOLTAGE_CHANNEL_DIFF(5, 4, 13),115 ADC0832_VOLTAGE_CHANNEL_DIFF(6, 7, 14),116 ADC0832_VOLTAGE_CHANNEL_DIFF(7, 6, 15),117 IIO_CHAN_SOFT_TIMESTAMP(16),118};119 120static int adc0831_adc_conversion(struct adc0832 *adc)121{122 struct spi_device *spi = adc->spi;123 int ret;124 125 ret = spi_read(spi, &adc->rx_buf, 2);126 if (ret)127 return ret;128 129 /*130 * Skip TRI-STATE and a leading zero131 */132 return (adc->rx_buf[0] << 2 & 0xff) | (adc->rx_buf[1] >> 6);133}134 135static int adc0832_adc_conversion(struct adc0832 *adc, int channel,136 bool differential)137{138 struct spi_device *spi = adc->spi;139 struct spi_transfer xfer = {140 .tx_buf = adc->tx_buf,141 .rx_buf = adc->rx_buf,142 .len = 2,143 };144 int ret;145 146 if (!adc->mux_bits)147 return adc0831_adc_conversion(adc);148 149 /* start bit */150 adc->tx_buf[0] = 1 << (adc->mux_bits + 1);151 /* single-ended or differential */152 adc->tx_buf[0] |= differential ? 0 : (1 << adc->mux_bits);153 /* odd / sign */154 adc->tx_buf[0] |= (channel % 2) << (adc->mux_bits - 1);155 /* select */156 if (adc->mux_bits > 1)157 adc->tx_buf[0] |= channel / 2;158 159 /* align Data output BIT7 (MSB) to 8-bit boundary */160 adc->tx_buf[0] <<= 1;161 162 ret = spi_sync_transfer(spi, &xfer, 1);163 if (ret)164 return ret;165 166 return adc->rx_buf[1];167}168 169static int adc0832_read_raw(struct iio_dev *iio,170 struct iio_chan_spec const *channel, int *value,171 int *shift, long mask)172{173 struct adc0832 *adc = iio_priv(iio);174 175 switch (mask) {176 case IIO_CHAN_INFO_RAW:177 mutex_lock(&adc->lock);178 *value = adc0832_adc_conversion(adc, channel->channel,179 channel->differential);180 mutex_unlock(&adc->lock);181 if (*value < 0)182 return *value;183 184 return IIO_VAL_INT;185 case IIO_CHAN_INFO_SCALE:186 *value = regulator_get_voltage(adc->reg);187 if (*value < 0)188 return *value;189 190 /* convert regulator output voltage to mV */191 *value /= 1000;192 *shift = 8;193 194 return IIO_VAL_FRACTIONAL_LOG2;195 }196 197 return -EINVAL;198}199 200static const struct iio_info adc0832_info = {201 .read_raw = adc0832_read_raw,202};203 204static irqreturn_t adc0832_trigger_handler(int irq, void *p)205{206 struct iio_poll_func *pf = p;207 struct iio_dev *indio_dev = pf->indio_dev;208 struct adc0832 *adc = iio_priv(indio_dev);209 int scan_index;210 int i = 0;211 212 mutex_lock(&adc->lock);213 214 iio_for_each_active_channel(indio_dev, scan_index) {215 const struct iio_chan_spec *scan_chan =216 &indio_dev->channels[scan_index];217 int ret = adc0832_adc_conversion(adc, scan_chan->channel,218 scan_chan->differential);219 if (ret < 0) {220 dev_warn(&adc->spi->dev,221 "failed to get conversion data\n");222 goto out;223 }224 225 adc->data[i] = ret;226 i++;227 }228 iio_push_to_buffers_with_timestamp(indio_dev, adc->data,229 iio_get_time_ns(indio_dev));230out:231 mutex_unlock(&adc->lock);232 233 iio_trigger_notify_done(indio_dev->trig);234 235 return IRQ_HANDLED;236}237 238static void adc0832_reg_disable(void *reg)239{240 regulator_disable(reg);241}242 243static int adc0832_probe(struct spi_device *spi)244{245 struct iio_dev *indio_dev;246 struct adc0832 *adc;247 int ret;248 249 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));250 if (!indio_dev)251 return -ENOMEM;252 253 adc = iio_priv(indio_dev);254 adc->spi = spi;255 mutex_init(&adc->lock);256 257 indio_dev->name = spi_get_device_id(spi)->name;258 indio_dev->info = &adc0832_info;259 indio_dev->modes = INDIO_DIRECT_MODE;260 261 switch (spi_get_device_id(spi)->driver_data) {262 case adc0831:263 adc->mux_bits = 0;264 indio_dev->channels = adc0831_channels;265 indio_dev->num_channels = ARRAY_SIZE(adc0831_channels);266 break;267 case adc0832:268 adc->mux_bits = 1;269 indio_dev->channels = adc0832_channels;270 indio_dev->num_channels = ARRAY_SIZE(adc0832_channels);271 break;272 case adc0834:273 adc->mux_bits = 2;274 indio_dev->channels = adc0834_channels;275 indio_dev->num_channels = ARRAY_SIZE(adc0834_channels);276 break;277 case adc0838:278 adc->mux_bits = 3;279 indio_dev->channels = adc0838_channels;280 indio_dev->num_channels = ARRAY_SIZE(adc0838_channels);281 break;282 default:283 return -EINVAL;284 }285 286 adc->reg = devm_regulator_get(&spi->dev, "vref");287 if (IS_ERR(adc->reg))288 return PTR_ERR(adc->reg);289 290 ret = regulator_enable(adc->reg);291 if (ret)292 return ret;293 294 ret = devm_add_action_or_reset(&spi->dev, adc0832_reg_disable,295 adc->reg);296 if (ret)297 return ret;298 299 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,300 adc0832_trigger_handler, NULL);301 if (ret)302 return ret;303 304 return devm_iio_device_register(&spi->dev, indio_dev);305}306 307static const struct of_device_id adc0832_dt_ids[] = {308 { .compatible = "ti,adc0831", },309 { .compatible = "ti,adc0832", },310 { .compatible = "ti,adc0834", },311 { .compatible = "ti,adc0838", },312 { }313};314MODULE_DEVICE_TABLE(of, adc0832_dt_ids);315 316static const struct spi_device_id adc0832_id[] = {317 { "adc0831", adc0831 },318 { "adc0832", adc0832 },319 { "adc0834", adc0834 },320 { "adc0838", adc0838 },321 { }322};323MODULE_DEVICE_TABLE(spi, adc0832_id);324 325static struct spi_driver adc0832_driver = {326 .driver = {327 .name = "adc0832",328 .of_match_table = adc0832_dt_ids,329 },330 .probe = adc0832_probe,331 .id_table = adc0832_id,332};333module_spi_driver(adc0832_driver);334 335MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");336MODULE_DESCRIPTION("ADC0831/ADC0832/ADC0834/ADC0838 driver");337MODULE_LICENSE("GPL v2");338