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1// SPDX-License-Identifier: GPL-2.02/*3 * Analog Devices AD7292 SPI ADC driver4 *5 * Copyright 2019 Analog Devices Inc.6 */7 8#include <linux/bitfield.h>9#include <linux/device.h>10#include <linux/module.h>11#include <linux/mod_devicetable.h>12#include <linux/property.h>13#include <linux/regulator/consumer.h>14#include <linux/spi/spi.h>15 16#include <linux/iio/iio.h>17 18#define ADI_VENDOR_ID 0x001819 20#define AD7292_INTERNAL_REF_MV 125021 22/* AD7292 registers definition */23#define AD7292_REG_VENDOR_ID 0x0024#define AD7292_REG_CONF_BANK 0x0525#define AD7292_REG_CONV_COMM 0x0E26#define AD7292_REG_ADC_CH(x) (0x10 + (x))27 28/* AD7292 configuration bank subregisters definition */29#define AD7292_BANK_REG_VIN_RNG0 0x1030#define AD7292_BANK_REG_VIN_RNG1 0x1131#define AD7292_BANK_REG_SAMP_MODE 0x1232 33#define AD7292_RD_FLAG_MSK(x) (BIT(7) | ((x) & 0x3F))34 35/* AD7292_REG_ADC_CONVERSION */36#define AD7292_ADC_DATA_MASK GENMASK(15, 6)37#define AD7292_ADC_DATA(x) FIELD_GET(AD7292_ADC_DATA_MASK, x)38 39/* AD7292_CHANNEL_SAMPLING_MODE */40#define AD7292_CH_SAMP_MODE(reg, ch) (((reg) >> 8) & BIT(ch))41 42/* AD7292_CHANNEL_VIN_RANGE */43#define AD7292_CH_VIN_RANGE(reg, ch) ((reg) & BIT(ch))44 45#define AD7292_VOLTAGE_CHAN(_chan) \46{ \47 .type = IIO_VOLTAGE, \48 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \49 BIT(IIO_CHAN_INFO_SCALE), \50 .indexed = 1, \51 .channel = _chan, \52}53 54static const struct iio_chan_spec ad7292_channels[] = {55 AD7292_VOLTAGE_CHAN(0),56 AD7292_VOLTAGE_CHAN(1),57 AD7292_VOLTAGE_CHAN(2),58 AD7292_VOLTAGE_CHAN(3),59 AD7292_VOLTAGE_CHAN(4),60 AD7292_VOLTAGE_CHAN(5),61 AD7292_VOLTAGE_CHAN(6),62 AD7292_VOLTAGE_CHAN(7)63};64 65static const struct iio_chan_spec ad7292_channels_diff[] = {66 {67 .type = IIO_VOLTAGE,68 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),69 .indexed = 1,70 .differential = 1,71 .channel = 0,72 .channel2 = 1,73 },74 AD7292_VOLTAGE_CHAN(2),75 AD7292_VOLTAGE_CHAN(3),76 AD7292_VOLTAGE_CHAN(4),77 AD7292_VOLTAGE_CHAN(5),78 AD7292_VOLTAGE_CHAN(6),79 AD7292_VOLTAGE_CHAN(7)80};81 82struct ad7292_state {83 struct spi_device *spi;84 unsigned short vref_mv;85 86 __be16 d16 __aligned(IIO_DMA_MINALIGN);87 u8 d8[2];88};89 90static int ad7292_spi_reg_read(struct ad7292_state *st, unsigned int addr)91{92 int ret;93 94 st->d8[0] = AD7292_RD_FLAG_MSK(addr);95 96 ret = spi_write_then_read(st->spi, st->d8, 1, &st->d16, 2);97 if (ret < 0)98 return ret;99 100 return be16_to_cpu(st->d16);101}102 103static int ad7292_spi_subreg_read(struct ad7292_state *st, unsigned int addr,104 unsigned int sub_addr, unsigned int len)105{106 unsigned int shift = 16 - (8 * len);107 int ret;108 109 st->d8[0] = AD7292_RD_FLAG_MSK(addr);110 st->d8[1] = sub_addr;111 112 ret = spi_write_then_read(st->spi, st->d8, 2, &st->d16, len);113 if (ret < 0)114 return ret;115 116 return (be16_to_cpu(st->d16) >> shift);117}118 119static int ad7292_single_conversion(struct ad7292_state *st,120 unsigned int chan_addr)121{122 int ret;123 124 struct spi_transfer t[] = {125 {126 .tx_buf = &st->d8,127 .len = 4,128 .delay = {129 .value = 6,130 .unit = SPI_DELAY_UNIT_USECS131 },132 }, {133 .rx_buf = &st->d16,134 .len = 2,135 },136 };137 138 st->d8[0] = chan_addr;139 st->d8[1] = AD7292_RD_FLAG_MSK(AD7292_REG_CONV_COMM);140 141 ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));142 143 if (ret < 0)144 return ret;145 146 return be16_to_cpu(st->d16);147}148 149static int ad7292_vin_range_multiplier(struct ad7292_state *st, int channel)150{151 int samp_mode, range0, range1, factor = 1;152 153 /*154 * Every AD7292 ADC channel may have its input range adjusted according155 * to the settings at the ADC sampling mode and VIN range subregisters.156 * For a given channel, the minimum input range is equal to Vref, and it157 * may be increased by a multiplier factor of 2 or 4 according to the158 * following rule:159 * If channel is being sampled with respect to AGND:160 * factor = 4 if VIN range0 and VIN range1 equal 0161 * factor = 2 if only one of VIN ranges equal 1162 * factor = 1 if both VIN range0 and VIN range1 equal 1163 * If channel is being sampled with respect to AVDD:164 * factor = 4 if VIN range0 and VIN range1 equal 0165 * Behavior is undefined if any of VIN range doesn't equal 0166 */167 168 samp_mode = ad7292_spi_subreg_read(st, AD7292_REG_CONF_BANK,169 AD7292_BANK_REG_SAMP_MODE, 2);170 171 if (samp_mode < 0)172 return samp_mode;173 174 range0 = ad7292_spi_subreg_read(st, AD7292_REG_CONF_BANK,175 AD7292_BANK_REG_VIN_RNG0, 2);176 177 if (range0 < 0)178 return range0;179 180 range1 = ad7292_spi_subreg_read(st, AD7292_REG_CONF_BANK,181 AD7292_BANK_REG_VIN_RNG1, 2);182 183 if (range1 < 0)184 return range1;185 186 if (AD7292_CH_SAMP_MODE(samp_mode, channel)) {187 /* Sampling with respect to AGND */188 if (!AD7292_CH_VIN_RANGE(range0, channel))189 factor *= 2;190 191 if (!AD7292_CH_VIN_RANGE(range1, channel))192 factor *= 2;193 194 } else {195 /* Sampling with respect to AVDD */196 if (AD7292_CH_VIN_RANGE(range0, channel) ||197 AD7292_CH_VIN_RANGE(range1, channel))198 return -EPERM;199 200 factor = 4;201 }202 203 return factor;204}205 206static int ad7292_read_raw(struct iio_dev *indio_dev,207 const struct iio_chan_spec *chan,208 int *val, int *val2, long info)209{210 struct ad7292_state *st = iio_priv(indio_dev);211 unsigned int ch_addr;212 int ret;213 214 switch (info) {215 case IIO_CHAN_INFO_RAW:216 ch_addr = AD7292_REG_ADC_CH(chan->channel);217 ret = ad7292_single_conversion(st, ch_addr);218 if (ret < 0)219 return ret;220 221 *val = AD7292_ADC_DATA(ret);222 223 return IIO_VAL_INT;224 case IIO_CHAN_INFO_SCALE:225 /*226 * To convert a raw value to standard units, the IIO defines227 * this formula: Scaled value = (raw + offset) * scale.228 * For the scale to be a correct multiplier for (raw + offset),229 * it must be calculated as the input range divided by the230 * number of possible distinct input values. Given the ADC data231 * is 10 bit long, it may assume 2^10 distinct values.232 * Hence, scale = range / 2^10. The IIO_VAL_FRACTIONAL_LOG2233 * return type indicates to the IIO API to divide *val by 2 to234 * the power of *val2 when returning from read_raw.235 */236 237 ret = ad7292_vin_range_multiplier(st, chan->channel);238 if (ret < 0)239 return ret;240 241 *val = st->vref_mv * ret;242 *val2 = 10;243 return IIO_VAL_FRACTIONAL_LOG2;244 default:245 break;246 }247 return -EINVAL;248}249 250static const struct iio_info ad7292_info = {251 .read_raw = ad7292_read_raw,252};253 254static int ad7292_probe(struct spi_device *spi)255{256 struct ad7292_state *st;257 struct iio_dev *indio_dev;258 bool diff_channels = false;259 int ret;260 261 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));262 if (!indio_dev)263 return -ENOMEM;264 265 st = iio_priv(indio_dev);266 st->spi = spi;267 268 ret = ad7292_spi_reg_read(st, AD7292_REG_VENDOR_ID);269 if (ret != ADI_VENDOR_ID) {270 dev_err(&spi->dev, "Wrong vendor id 0x%x\n", ret);271 return -EINVAL;272 }273 274 ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vref");275 if (ret < 0 && ret != -ENODEV)276 return ret;277 278 st->vref_mv = ret == -ENODEV ? AD7292_INTERNAL_REF_MV : ret / 1000;279 280 indio_dev->name = spi_get_device_id(spi)->name;281 indio_dev->modes = INDIO_DIRECT_MODE;282 indio_dev->info = &ad7292_info;283 284 device_for_each_child_node_scoped(&spi->dev, child) {285 diff_channels = fwnode_property_read_bool(child,286 "diff-channels");287 if (diff_channels)288 break;289 }290 291 if (diff_channels) {292 indio_dev->num_channels = ARRAY_SIZE(ad7292_channels_diff);293 indio_dev->channels = ad7292_channels_diff;294 } else {295 indio_dev->num_channels = ARRAY_SIZE(ad7292_channels);296 indio_dev->channels = ad7292_channels;297 }298 299 return devm_iio_device_register(&spi->dev, indio_dev);300}301 302static const struct spi_device_id ad7292_id_table[] = {303 { "ad7292", 0 },304 { }305};306MODULE_DEVICE_TABLE(spi, ad7292_id_table);307 308static const struct of_device_id ad7292_of_match[] = {309 { .compatible = "adi,ad7292" },310 { }311};312MODULE_DEVICE_TABLE(of, ad7292_of_match);313 314static struct spi_driver ad7292_driver = {315 .driver = {316 .name = "ad7292",317 .of_match_table = ad7292_of_match,318 },319 .probe = ad7292_probe,320 .id_table = ad7292_id_table,321};322module_spi_driver(ad7292_driver);323 324MODULE_AUTHOR("Marcelo Schmitt <marcelo.schmitt1@gmail.com>");325MODULE_DESCRIPTION("Analog Devices AD7292 ADC driver");326MODULE_LICENSE("GPL v2");327