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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * TI ADC108S102 SPI ADC driver4 *5 * Copyright (c) 2013-2015 Intel Corporation.6 * Copyright (c) 2017 Siemens AG7 *8 * This IIO device driver is designed to work with the following9 * analog to digital converters from Texas Instruments:10 * ADC108S10211 * ADC128S10212 * The communication with ADC chip is via the SPI bus (mode 3).13 */14 15#include <linux/acpi.h>16#include <linux/iio/iio.h>17#include <linux/iio/buffer.h>18#include <linux/iio/types.h>19#include <linux/iio/triggered_buffer.h>20#include <linux/iio/trigger_consumer.h>21#include <linux/interrupt.h>22#include <linux/module.h>23#include <linux/mod_devicetable.h>24#include <linux/property.h>25#include <linux/regulator/consumer.h>26#include <linux/spi/spi.h>27 28/*29 * In case of ACPI, we use the hard-wired 5000 mV of the Galileo and IOT200030 * boards as default for the reference pin VA. Device tree users encode that31 * via the vref-supply regulator.32 */33#define ADC108S102_VA_MV_ACPI_DEFAULT 500034 35/*36 * Defining the ADC resolution being 12 bits, we can use the same driver for37 * both ADC108S102 (10 bits resolution) and ADC128S102 (12 bits resolution)38 * chips. The ADC108S102 effectively returns a 12-bit result with the 239 * least-significant bits unset.40 */41#define ADC108S102_BITS 1242#define ADC108S102_MAX_CHANNELS 843 44/*45 * 16-bit SPI command format:46 * [15:14] Ignored47 * [13:11] 3-bit channel address48 * [10:0] Ignored49 */50#define ADC108S102_CMD(ch) ((u16)(ch) << 11)51 52/*53 * 16-bit SPI response format:54 * [15:12] Zeros55 * [11:0] 12-bit ADC sample (for ADC108S102, [1:0] will always be 0).56 */57#define ADC108S102_RES_DATA(res) ((u16)res & GENMASK(11, 0))58 59struct adc108s102_state {60 struct spi_device *spi;61 u32 va_millivolt;62 /* SPI transfer used by triggered buffer handler*/63 struct spi_transfer ring_xfer;64 /* SPI transfer used by direct scan */65 struct spi_transfer scan_single_xfer;66 /* SPI message used by ring_xfer SPI transfer */67 struct spi_message ring_msg;68 /* SPI message used by scan_single_xfer SPI transfer */69 struct spi_message scan_single_msg;70 71 /*72 * SPI message buffers:73 * tx_buf: |C0|C1|C2|C3|C4|C5|C6|C7|XX|74 * rx_buf: |XX|R0|R1|R2|R3|R4|R5|R6|R7|tt|tt|tt|tt|75 *76 * tx_buf: 8 channel read commands, plus 1 dummy command77 * rx_buf: 1 dummy response, 8 channel responses78 */79 __be16 rx_buf[9] __aligned(IIO_DMA_MINALIGN);80 __be16 tx_buf[9] __aligned(IIO_DMA_MINALIGN);81};82 83#define ADC108S102_V_CHAN(index) \84 { \85 .type = IIO_VOLTAGE, \86 .indexed = 1, \87 .channel = index, \88 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \89 BIT(IIO_CHAN_INFO_SCALE), \90 .address = index, \91 .scan_index = index, \92 .scan_type = { \93 .sign = 'u', \94 .realbits = ADC108S102_BITS, \95 .storagebits = 16, \96 .endianness = IIO_BE, \97 }, \98 }99 100static const struct iio_chan_spec adc108s102_channels[] = {101 ADC108S102_V_CHAN(0),102 ADC108S102_V_CHAN(1),103 ADC108S102_V_CHAN(2),104 ADC108S102_V_CHAN(3),105 ADC108S102_V_CHAN(4),106 ADC108S102_V_CHAN(5),107 ADC108S102_V_CHAN(6),108 ADC108S102_V_CHAN(7),109 IIO_CHAN_SOFT_TIMESTAMP(8),110};111 112static int adc108s102_update_scan_mode(struct iio_dev *indio_dev,113 unsigned long const *active_scan_mask)114{115 struct adc108s102_state *st = iio_priv(indio_dev);116 unsigned int bit, cmds;117 118 /*119 * Fill in the first x shorts of tx_buf with the number of channels120 * enabled for sampling by the triggered buffer.121 */122 cmds = 0;123 for_each_set_bit(bit, active_scan_mask, ADC108S102_MAX_CHANNELS)124 st->tx_buf[cmds++] = cpu_to_be16(ADC108S102_CMD(bit));125 126 /* One dummy command added, to clock in the last response */127 st->tx_buf[cmds++] = 0x00;128 129 /* build SPI ring message */130 st->ring_xfer.tx_buf = &st->tx_buf[0];131 st->ring_xfer.rx_buf = &st->rx_buf[0];132 st->ring_xfer.len = cmds * sizeof(st->tx_buf[0]);133 134 spi_message_init_with_transfers(&st->ring_msg, &st->ring_xfer, 1);135 136 return 0;137}138 139static irqreturn_t adc108s102_trigger_handler(int irq, void *p)140{141 struct iio_poll_func *pf = p;142 struct iio_dev *indio_dev = pf->indio_dev;143 struct adc108s102_state *st = iio_priv(indio_dev);144 int ret;145 146 ret = spi_sync(st->spi, &st->ring_msg);147 if (ret < 0)148 goto out_notify;149 150 /* Skip the dummy response in the first slot */151 iio_push_to_buffers_with_ts_unaligned(indio_dev,152 &st->rx_buf[1],153 st->ring_xfer.len - sizeof(st->rx_buf[1]),154 iio_get_time_ns(indio_dev));155 156out_notify:157 iio_trigger_notify_done(indio_dev->trig);158 159 return IRQ_HANDLED;160}161 162static int adc108s102_scan_direct(struct adc108s102_state *st, unsigned int ch)163{164 int ret;165 166 st->tx_buf[0] = cpu_to_be16(ADC108S102_CMD(ch));167 ret = spi_sync(st->spi, &st->scan_single_msg);168 if (ret)169 return ret;170 171 /* Skip the dummy response in the first slot */172 return be16_to_cpu(st->rx_buf[1]);173}174 175static int adc108s102_read_raw(struct iio_dev *indio_dev,176 struct iio_chan_spec const *chan,177 int *val, int *val2, long m)178{179 struct adc108s102_state *st = iio_priv(indio_dev);180 int ret;181 182 switch (m) {183 case IIO_CHAN_INFO_RAW:184 ret = iio_device_claim_direct_mode(indio_dev);185 if (ret)186 return ret;187 188 ret = adc108s102_scan_direct(st, chan->address);189 190 iio_device_release_direct_mode(indio_dev);191 192 if (ret < 0)193 return ret;194 195 *val = ADC108S102_RES_DATA(ret);196 197 return IIO_VAL_INT;198 case IIO_CHAN_INFO_SCALE:199 if (chan->type != IIO_VOLTAGE)200 break;201 202 *val = st->va_millivolt;203 *val2 = chan->scan_type.realbits;204 205 return IIO_VAL_FRACTIONAL_LOG2;206 default:207 break;208 }209 210 return -EINVAL;211}212 213static const struct iio_info adc108s102_info = {214 .read_raw = &adc108s102_read_raw,215 .update_scan_mode = &adc108s102_update_scan_mode,216};217 218static int adc108s102_probe(struct spi_device *spi)219{220 struct adc108s102_state *st;221 struct iio_dev *indio_dev;222 int ret;223 224 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));225 if (!indio_dev)226 return -ENOMEM;227 228 st = iio_priv(indio_dev);229 230 if (ACPI_COMPANION(&spi->dev)) {231 st->va_millivolt = ADC108S102_VA_MV_ACPI_DEFAULT;232 } else {233 ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vref");234 if (ret < 0)235 return dev_err_probe(&spi->dev, ret, "failed get vref voltage\n");236 237 st->va_millivolt = ret / 1000;238 }239 240 st->spi = spi;241 242 indio_dev->name = spi->modalias;243 indio_dev->modes = INDIO_DIRECT_MODE;244 indio_dev->channels = adc108s102_channels;245 indio_dev->num_channels = ARRAY_SIZE(adc108s102_channels);246 indio_dev->info = &adc108s102_info;247 248 /* Setup default message */249 st->scan_single_xfer.tx_buf = st->tx_buf;250 st->scan_single_xfer.rx_buf = st->rx_buf;251 st->scan_single_xfer.len = 2 * sizeof(st->tx_buf[0]);252 253 spi_message_init_with_transfers(&st->scan_single_msg,254 &st->scan_single_xfer, 1);255 256 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,257 &adc108s102_trigger_handler,258 NULL);259 if (ret)260 return ret;261 262 ret = devm_iio_device_register(&spi->dev, indio_dev);263 if (ret)264 dev_err(&spi->dev, "Failed to register IIO device\n");265 return ret;266}267 268static const struct of_device_id adc108s102_of_match[] = {269 { .compatible = "ti,adc108s102" },270 { }271};272MODULE_DEVICE_TABLE(of, adc108s102_of_match);273 274static const struct acpi_device_id adc108s102_acpi_ids[] = {275 { "INT3495", 0 },276 { }277};278MODULE_DEVICE_TABLE(acpi, adc108s102_acpi_ids);279 280static const struct spi_device_id adc108s102_id[] = {281 { "adc108s102", 0 },282 { }283};284MODULE_DEVICE_TABLE(spi, adc108s102_id);285 286static struct spi_driver adc108s102_driver = {287 .driver = {288 .name = "adc108s102",289 .of_match_table = adc108s102_of_match,290 .acpi_match_table = adc108s102_acpi_ids,291 },292 .probe = adc108s102_probe,293 .id_table = adc108s102_id,294};295module_spi_driver(adc108s102_driver);296 297MODULE_AUTHOR("Bogdan Pricop <bogdan.pricop@emutex.com>");298MODULE_DESCRIPTION("Texas Instruments ADC108S102 and ADC128S102 driver");299MODULE_LICENSE("GPL v2");300