drivers/iio/adc/ti-adc0832.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ADC0831/ADC0832/ADC0834/ADC0838 8-bit ADC driver
   4  *
   5  * Copyright (c) 2016 Akinobu Mita <[email protected]>
   6  *
   7  * Datasheet: https://www.ti.com/lit/ds/symlink/adc0832-n.pdf
   8  */
   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
  20 enum {
  21         adc0831,
  22         adc0832,
  23         adc0834,
  24         adc0838,
  25 };
  26
  27 struct adc0832 {
  28         struct spi_device *spi;
  29         struct regulator *reg;
  30         struct mutex lock;
  31         u8 mux_bits;
  32
  33         u8 tx_buf[2] ____cacheline_aligned;
  34         u8 rx_buf[2];
  35 };
  36
  37 #define ADC0832_VOLTAGE_CHANNEL(chan)                                   \
  38         {                                                               \
  39                 .type = IIO_VOLTAGE,                                    \
  40                 .indexed = 1,                                           \
  41                 .channel = chan,                                        \
  42                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  43                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  44                 .scan_index = chan,                                     \
  45                 .scan_type = {                                          \
  46                         .sign = 'u',                                    \
  47                         .realbits = 8,                                  \
  48                         .storagebits = 8,                               \
  49                 },                                                      \
  50         }
  51
  52 #define ADC0832_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si)                  \
  53         {                                                               \
  54                 .type = IIO_VOLTAGE,                                    \
  55                 .indexed = 1,                                           \
  56                 .channel = (chan1),                                     \
  57                 .channel2 = (chan2),                                    \
  58                 .differential = 1,                                      \
  59                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  60                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  61                 .scan_index = si,                                       \
  62                 .scan_type = {                                          \
  63                         .sign = 'u',                                    \
  64                         .realbits = 8,                                  \
  65                         .storagebits = 8,                               \
  66                 },                                                      \
  67         }
  68
  69 static const struct iio_chan_spec adc0831_channels[] = {
  70         ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 0),
  71         IIO_CHAN_SOFT_TIMESTAMP(1),
  72 };
  73
  74 static const struct iio_chan_spec adc0832_channels[] = {
  75         ADC0832_VOLTAGE_CHANNEL(0),
  76         ADC0832_VOLTAGE_CHANNEL(1),
  77         ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 2),
  78         ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 3),
  79         IIO_CHAN_SOFT_TIMESTAMP(4),
  80 };
  81
  82 static const struct iio_chan_spec adc0834_channels[] = {
  83         ADC0832_VOLTAGE_CHANNEL(0),
  84         ADC0832_VOLTAGE_CHANNEL(1),
  85         ADC0832_VOLTAGE_CHANNEL(2),
  86         ADC0832_VOLTAGE_CHANNEL(3),
  87         ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 4),
  88         ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 5),
  89         ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 6),
  90         ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 7),
  91         IIO_CHAN_SOFT_TIMESTAMP(8),
  92 };
  93
  94 static const struct iio_chan_spec adc0838_channels[] = {
  95         ADC0832_VOLTAGE_CHANNEL(0),
  96         ADC0832_VOLTAGE_CHANNEL(1),
  97         ADC0832_VOLTAGE_CHANNEL(2),
  98         ADC0832_VOLTAGE_CHANNEL(3),
  99         ADC0832_VOLTAGE_CHANNEL(4),
 100         ADC0832_VOLTAGE_CHANNEL(5),
 101         ADC0832_VOLTAGE_CHANNEL(6),
 102         ADC0832_VOLTAGE_CHANNEL(7),
 103         ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
 104         ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 9),
 105         ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 10),
 106         ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 11),
 107         ADC0832_VOLTAGE_CHANNEL_DIFF(4, 5, 12),
 108         ADC0832_VOLTAGE_CHANNEL_DIFF(5, 4, 13),
 109         ADC0832_VOLTAGE_CHANNEL_DIFF(6, 7, 14),
 110         ADC0832_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
 111         IIO_CHAN_SOFT_TIMESTAMP(16),
 112 };
 113
 114 static int adc0831_adc_conversion(struct adc0832 *adc)
 115 {
 116         struct spi_device *spi = adc->spi;
 117         int ret;
 118
 119         ret = spi_read(spi, &adc->rx_buf, 2);
 120         if (ret)
 121                 return ret;
 122
 123         /*
 124          * Skip TRI-STATE and a leading zero
 125          */
 126         return (adc->rx_buf[0] << 2 & 0xff) | (adc->rx_buf[1] >> 6);
 127 }
 128
 129 static int adc0832_adc_conversion(struct adc0832 *adc, int channel,
 130                                 bool differential)
 131 {
 132         struct spi_device *spi = adc->spi;
 133         struct spi_transfer xfer = {
 134                 .tx_buf = adc->tx_buf,
 135                 .rx_buf = adc->rx_buf,
 136                 .len = 2,
 137         };
 138         int ret;
 139
 140         if (!adc->mux_bits)
 141                 return adc0831_adc_conversion(adc);
 142
 143         /* start bit */
 144         adc->tx_buf[0] = 1 << (adc->mux_bits + 1);
 145         /* single-ended or differential */
 146         adc->tx_buf[0] |= differential ? 0 : (1 << adc->mux_bits);
 147         /* odd / sign */
 148         adc->tx_buf[0] |= (channel % 2) << (adc->mux_bits - 1);
 149         /* select */
 150         if (adc->mux_bits > 1)
 151                 adc->tx_buf[0] |= channel / 2;
 152
 153         /* align Data output BIT7 (MSB) to 8-bit boundary */
 154         adc->tx_buf[0] <<= 1;
 155
 156         ret = spi_sync_transfer(spi, &xfer, 1);
 157         if (ret)
 158                 return ret;
 159
 160         return adc->rx_buf[1];
 161 }
 162
 163 static int adc0832_read_raw(struct iio_dev *iio,
 164                         struct iio_chan_spec const *channel, int *value,
 165                         int *shift, long mask)
 166 {
 167         struct adc0832 *adc = iio_priv(iio);
 168
 169         switch (mask) {
 170         case IIO_CHAN_INFO_RAW:
 171                 mutex_lock(&adc->lock);
 172                 *value = adc0832_adc_conversion(adc, channel->channel,
 173                                                 channel->differential);
 174                 mutex_unlock(&adc->lock);
 175                 if (*value < 0)
 176                         return *value;
 177
 178                 return IIO_VAL_INT;
 179         case IIO_CHAN_INFO_SCALE:
 180                 *value = regulator_get_voltage(adc->reg);
 181                 if (*value < 0)
 182                         return *value;
 183
 184                 /* convert regulator output voltage to mV */
 185                 *value /= 1000;
 186                 *shift = 8;
 187
 188                 return IIO_VAL_FRACTIONAL_LOG2;
 189         }
 190
 191         return -EINVAL;
 192 }
 193
 194 static const struct iio_info adc0832_info = {
 195         .read_raw = adc0832_read_raw,
 196 };
 197
 198 static irqreturn_t adc0832_trigger_handler(int irq, void *p)
 199 {
 200         struct iio_poll_func *pf = p;
 201         struct iio_dev *indio_dev = pf->indio_dev;
 202         struct adc0832 *adc = iio_priv(indio_dev);
 203         u8 data[24] = { }; /* 16x 1 byte ADC data + 8 bytes timestamp */
 204         int scan_index;
 205         int i = 0;
 206
 207         mutex_lock(&adc->lock);
 208
 209         for_each_set_bit(scan_index, indio_dev->active_scan_mask,
 210                          indio_dev->masklength) {
 211                 const struct iio_chan_spec *scan_chan =
 212                                 &indio_dev->channels[scan_index];
 213                 int ret = adc0832_adc_conversion(adc, scan_chan->channel,
 214                                                  scan_chan->differential);
 215                 if (ret < 0) {
 216                         dev_warn(&adc->spi->dev,
 217                                  "failed to get conversion data\n");
 218                         goto out;
 219                 }
 220
 221                 data[i] = ret;
 222                 i++;
 223         }
 224         iio_push_to_buffers_with_timestamp(indio_dev, data,
 225                                            iio_get_time_ns(indio_dev));
 226 out:
 227         mutex_unlock(&adc->lock);
 228
 229         iio_trigger_notify_done(indio_dev->trig);
 230
 231         return IRQ_HANDLED;
 232 }
 233
 234 static int adc0832_probe(struct spi_device *spi)
 235 {
 236         struct iio_dev *indio_dev;
 237         struct adc0832 *adc;
 238         int ret;
 239
 240         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
 241         if (!indio_dev)
 242                 return -ENOMEM;
 243
 244         adc = iio_priv(indio_dev);
 245         adc->spi = spi;
 246         mutex_init(&adc->lock);
 247
 248         indio_dev->name = spi_get_device_id(spi)->name;
 249         indio_dev->info = &adc0832_info;
 250         indio_dev->modes = INDIO_DIRECT_MODE;
 251
 252         switch (spi_get_device_id(spi)->driver_data) {
 253         case adc0831:
 254                 adc->mux_bits = 0;
 255                 indio_dev->channels = adc0831_channels;
 256                 indio_dev->num_channels = ARRAY_SIZE(adc0831_channels);
 257                 break;
 258         case adc0832:
 259                 adc->mux_bits = 1;
 260                 indio_dev->channels = adc0832_channels;
 261                 indio_dev->num_channels = ARRAY_SIZE(adc0832_channels);
 262                 break;
 263         case adc0834:
 264                 adc->mux_bits = 2;
 265                 indio_dev->channels = adc0834_channels;
 266                 indio_dev->num_channels = ARRAY_SIZE(adc0834_channels);
 267                 break;
 268         case adc0838:
 269                 adc->mux_bits = 3;
 270                 indio_dev->channels = adc0838_channels;
 271                 indio_dev->num_channels = ARRAY_SIZE(adc0838_channels);
 272                 break;
 273         default:
 274                 return -EINVAL;
 275         }
 276
 277         adc->reg = devm_regulator_get(&spi->dev, "vref");
 278         if (IS_ERR(adc->reg))
 279                 return PTR_ERR(adc->reg);
 280
 281         ret = regulator_enable(adc->reg);
 282         if (ret)
 283                 return ret;
 284
 285         spi_set_drvdata(spi, indio_dev);
 286
 287         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 288                                          adc0832_trigger_handler, NULL);
 289         if (ret)
 290                 goto err_reg_disable;
 291
 292         ret = iio_device_register(indio_dev);
 293         if (ret)
 294                 goto err_buffer_cleanup;
 295
 296         return 0;
 297 err_buffer_cleanup:
 298         iio_triggered_buffer_cleanup(indio_dev);
 299 err_reg_disable:
 300         regulator_disable(adc->reg);
 301
 302         return ret;
 303 }
 304
 305 static int adc0832_remove(struct spi_device *spi)
 306 {
 307         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 308         struct adc0832 *adc = iio_priv(indio_dev);
 309
 310         iio_device_unregister(indio_dev);
 311         iio_triggered_buffer_cleanup(indio_dev);
 312         regulator_disable(adc->reg);
 313
 314         return 0;
 315 }
 316
 317 static const struct of_device_id adc0832_dt_ids[] = {
 318         { .compatible = "ti,adc0831", },
 319         { .compatible = "ti,adc0832", },
 320         { .compatible = "ti,adc0834", },
 321         { .compatible = "ti,adc0838", },
 322         {}
 323 };
 324 MODULE_DEVICE_TABLE(of, adc0832_dt_ids);
 325
 326 static const struct spi_device_id adc0832_id[] = {
 327         { "adc0831", adc0831 },
 328         { "adc0832", adc0832 },
 329         { "adc0834", adc0834 },
 330         { "adc0838", adc0838 },
 331         {}
 332 };
 333 MODULE_DEVICE_TABLE(spi, adc0832_id);
 334
 335 static struct spi_driver adc0832_driver = {
 336         .driver = {
 337                 .name = "adc0832",
 338                 .of_match_table = adc0832_dt_ids,
 339         },
 340         .probe = adc0832_probe,
 341         .remove = adc0832_remove,
 342         .id_table = adc0832_id,
 343 };
 344 module_spi_driver(adc0832_driver);
 345
 346 MODULE_AUTHOR("Akinobu Mita <[email protected]>");
 347 MODULE_DESCRIPTION("ADC0831/ADC0832/ADC0834/ADC0838 driver");
 348 MODULE_LICENSE("GPL v2");