drivers/iio/adc/ad7887.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AD7887 SPI ADC driver
   4  *
   5  * Copyright 2010-2011 Analog Devices Inc.
   6  */
   7
   8 #include <linux/device.h>
   9 #include <linux/kernel.h>
  10 #include <linux/slab.h>
  11 #include <linux/sysfs.h>
  12 #include <linux/spi/spi.h>
  13 #include <linux/regulator/consumer.h>
  14 #include <linux/err.h>
  15 #include <linux/module.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/bitops.h>
  18
  19 #include <linux/iio/iio.h>
  20 #include <linux/iio/sysfs.h>
  21 #include <linux/iio/buffer.h>
  22
  23 #include <linux/iio/trigger_consumer.h>
  24 #include <linux/iio/triggered_buffer.h>
  25
  26 #include <linux/platform_data/ad7887.h>
  27
  28 #define AD7887_REF_DIS          BIT(5)  /* on-chip reference disable */
  29 #define AD7887_DUAL             BIT(4)  /* dual-channel mode */
  30 #define AD7887_CH_AIN1          BIT(3)  /* convert on channel 1, DUAL=1 */
  31 #define AD7887_CH_AIN0          0       /* convert on channel 0, DUAL=0,1 */
  32 #define AD7887_PM_MODE1         0       /* CS based shutdown */
  33 #define AD7887_PM_MODE2         1       /* full on */
  34 #define AD7887_PM_MODE3         2       /* auto shutdown after conversion */
  35 #define AD7887_PM_MODE4         3       /* standby mode */
  36
  37 enum ad7887_channels {
  38         AD7887_CH0,
  39         AD7887_CH0_CH1,
  40         AD7887_CH1,
  41 };
  42
  43 /**
  44  * struct ad7887_chip_info - chip specifc information
  45  * @int_vref_mv:        the internal reference voltage
  46  * @channel:            channel specification
  47  */
  48 struct ad7887_chip_info {
  49         u16                             int_vref_mv;
  50         struct iio_chan_spec            channel[3];
  51 };
  52
  53 struct ad7887_state {
  54         struct spi_device               *spi;
  55         const struct ad7887_chip_info   *chip_info;
  56         struct regulator                *reg;
  57         struct spi_transfer             xfer[4];
  58         struct spi_message              msg[3];
  59         struct spi_message              *ring_msg;
  60         unsigned char                   tx_cmd_buf[4];
  61
  62         /*
  63          * DMA (thus cache coherency maintenance) requires the
  64          * transfer buffers to live in their own cache lines.
  65          * Buffer needs to be large enough to hold two 16 bit samples and a
  66          * 64 bit aligned 64 bit timestamp.
  67          */
  68         unsigned char data[ALIGN(4, sizeof(s64)) + sizeof(s64)]
  69                 ____cacheline_aligned;
  70 };
  71
  72 enum ad7887_supported_device_ids {
  73         ID_AD7887
  74 };
  75
  76 static int ad7887_ring_preenable(struct iio_dev *indio_dev)
  77 {
  78         struct ad7887_state *st = iio_priv(indio_dev);
  79
  80         /* We know this is a single long so can 'cheat' */
  81         switch (*indio_dev->active_scan_mask) {
  82         case (1 << 0):
  83                 st->ring_msg = &st->msg[AD7887_CH0];
  84                 break;
  85         case (1 << 1):
  86                 st->ring_msg = &st->msg[AD7887_CH1];
  87                 /* Dummy read: push CH1 setting down to hardware */
  88                 spi_sync(st->spi, st->ring_msg);
  89                 break;
  90         case ((1 << 1) | (1 << 0)):
  91                 st->ring_msg = &st->msg[AD7887_CH0_CH1];
  92                 break;
  93         }
  94
  95         return 0;
  96 }
  97
  98 static int ad7887_ring_postdisable(struct iio_dev *indio_dev)
  99 {
 100         struct ad7887_state *st = iio_priv(indio_dev);
 101
 102         /* dummy read: restore default CH0 settin */
 103         return spi_sync(st->spi, &st->msg[AD7887_CH0]);
 104 }
 105
 106 /**
 107  * ad7887_trigger_handler() bh of trigger launched polling to ring buffer
 108  *
 109  * Currently there is no option in this driver to disable the saving of
 110  * timestamps within the ring.
 111  **/
 112 static irqreturn_t ad7887_trigger_handler(int irq, void *p)
 113 {
 114         struct iio_poll_func *pf = p;
 115         struct iio_dev *indio_dev = pf->indio_dev;
 116         struct ad7887_state *st = iio_priv(indio_dev);
 117         int b_sent;
 118
 119         b_sent = spi_sync(st->spi, st->ring_msg);
 120         if (b_sent)
 121                 goto done;
 122
 123         iio_push_to_buffers_with_timestamp(indio_dev, st->data,
 124                 iio_get_time_ns(indio_dev));
 125 done:
 126         iio_trigger_notify_done(indio_dev->trig);
 127
 128         return IRQ_HANDLED;
 129 }
 130
 131 static const struct iio_buffer_setup_ops ad7887_ring_setup_ops = {
 132         .preenable = &ad7887_ring_preenable,
 133         .postenable = &iio_triggered_buffer_postenable,
 134         .predisable = &iio_triggered_buffer_predisable,
 135         .postdisable = &ad7887_ring_postdisable,
 136 };
 137
 138 static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
 139 {
 140         int ret = spi_sync(st->spi, &st->msg[ch]);
 141         if (ret)
 142                 return ret;
 143
 144         return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1];
 145 }
 146
 147 static int ad7887_read_raw(struct iio_dev *indio_dev,
 148                            struct iio_chan_spec const *chan,
 149                            int *val,
 150                            int *val2,
 151                            long m)
 152 {
 153         int ret;
 154         struct ad7887_state *st = iio_priv(indio_dev);
 155
 156         switch (m) {
 157         case IIO_CHAN_INFO_RAW:
 158                 ret = iio_device_claim_direct_mode(indio_dev);
 159                 if (ret)
 160                         return ret;
 161                 ret = ad7887_scan_direct(st, chan->address);
 162                 iio_device_release_direct_mode(indio_dev);
 163
 164                 if (ret < 0)
 165                         return ret;
 166                 *val = ret >> chan->scan_type.shift;
 167                 *val &= GENMASK(chan->scan_type.realbits - 1, 0);
 168                 return IIO_VAL_INT;
 169         case IIO_CHAN_INFO_SCALE:
 170                 if (st->reg) {
 171                         *val = regulator_get_voltage(st->reg);
 172                         if (*val < 0)
 173                                 return *val;
 174                         *val /= 1000;
 175                 } else {
 176                         *val = st->chip_info->int_vref_mv;
 177                 }
 178
 179                 *val2 = chan->scan_type.realbits;
 180
 181                 return IIO_VAL_FRACTIONAL_LOG2;
 182         }
 183         return -EINVAL;
 184 }
 185
 186
 187 static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
 188         /*
 189          * More devices added in future
 190          */
 191         [ID_AD7887] = {
 192                 .channel[0] = {
 193                         .type = IIO_VOLTAGE,
 194                         .indexed = 1,
 195                         .channel = 1,
 196                         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 197                         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 198                         .address = 1,
 199                         .scan_index = 1,
 200                         .scan_type = {
 201                                 .sign = 'u',
 202                                 .realbits = 12,
 203                                 .storagebits = 16,
 204                                 .shift = 0,
 205                                 .endianness = IIO_BE,
 206                         },
 207                 },
 208                 .channel[1] = {
 209                         .type = IIO_VOLTAGE,
 210                         .indexed = 1,
 211                         .channel = 0,
 212                         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 213                         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 214                         .address = 0,
 215                         .scan_index = 0,
 216                         .scan_type = {
 217                                 .sign = 'u',
 218                                 .realbits = 12,
 219                                 .storagebits = 16,
 220                                 .shift = 0,
 221                                 .endianness = IIO_BE,
 222                         },
 223                 },
 224                 .channel[2] = IIO_CHAN_SOFT_TIMESTAMP(2),
 225                 .int_vref_mv = 2500,
 226         },
 227 };
 228
 229 static const struct iio_info ad7887_info = {
 230         .read_raw = &ad7887_read_raw,
 231 };
 232
 233 static int ad7887_probe(struct spi_device *spi)
 234 {
 235         struct ad7887_platform_data *pdata = spi->dev.platform_data;
 236         struct ad7887_state *st;
 237         struct iio_dev *indio_dev;
 238         uint8_t mode;
 239         int ret;
 240
 241         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 242         if (indio_dev == NULL)
 243                 return -ENOMEM;
 244
 245         st = iio_priv(indio_dev);
 246
 247         if (!pdata || !pdata->use_onchip_ref) {
 248                 st->reg = devm_regulator_get(&spi->dev, "vref");
 249                 if (IS_ERR(st->reg))
 250                         return PTR_ERR(st->reg);
 251
 252                 ret = regulator_enable(st->reg);
 253                 if (ret)
 254                         return ret;
 255         }
 256
 257         st->chip_info =
 258                 &ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 259
 260         spi_set_drvdata(spi, indio_dev);
 261         st->spi = spi;
 262
 263         /* Estabilish that the iio_dev is a child of the spi device */
 264         indio_dev->dev.parent = &spi->dev;
 265         indio_dev->dev.of_node = spi->dev.of_node;
 266         indio_dev->name = spi_get_device_id(spi)->name;
 267         indio_dev->info = &ad7887_info;
 268         indio_dev->modes = INDIO_DIRECT_MODE;
 269
 270         /* Setup default message */
 271
 272         mode = AD7887_PM_MODE4;
 273         if (!pdata || !pdata->use_onchip_ref)
 274                 mode |= AD7887_REF_DIS;
 275         if (pdata && pdata->en_dual)
 276                 mode |= AD7887_DUAL;
 277
 278         st->tx_cmd_buf[0] = AD7887_CH_AIN0 | mode;
 279
 280         st->xfer[0].rx_buf = &st->data[0];
 281         st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
 282         st->xfer[0].len = 2;
 283
 284         spi_message_init(&st->msg[AD7887_CH0]);
 285         spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);
 286
 287         if (pdata && pdata->en_dual) {
 288                 st->tx_cmd_buf[2] = AD7887_CH_AIN1 | mode;
 289
 290                 st->xfer[1].rx_buf = &st->data[0];
 291                 st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
 292                 st->xfer[1].len = 2;
 293
 294                 st->xfer[2].rx_buf = &st->data[2];
 295                 st->xfer[2].tx_buf = &st->tx_cmd_buf[0];
 296                 st->xfer[2].len = 2;
 297
 298                 spi_message_init(&st->msg[AD7887_CH0_CH1]);
 299                 spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
 300                 spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);
 301
 302                 st->xfer[3].rx_buf = &st->data[2];
 303                 st->xfer[3].tx_buf = &st->tx_cmd_buf[2];
 304                 st->xfer[3].len = 2;
 305
 306                 spi_message_init(&st->msg[AD7887_CH1]);
 307                 spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);
 308
 309                 indio_dev->channels = st->chip_info->channel;
 310                 indio_dev->num_channels = 3;
 311         } else {
 312                 indio_dev->channels = &st->chip_info->channel[1];
 313                 indio_dev->num_channels = 2;
 314         }
 315
 316         ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
 317                         &ad7887_trigger_handler, &ad7887_ring_setup_ops);
 318         if (ret)
 319                 goto error_disable_reg;
 320
 321         ret = iio_device_register(indio_dev);
 322         if (ret)
 323                 goto error_unregister_ring;
 324
 325         return 0;
 326 error_unregister_ring:
 327         iio_triggered_buffer_cleanup(indio_dev);
 328 error_disable_reg:
 329         if (st->reg)
 330                 regulator_disable(st->reg);
 331
 332         return ret;
 333 }
 334
 335 static int ad7887_remove(struct spi_device *spi)
 336 {
 337         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 338         struct ad7887_state *st = iio_priv(indio_dev);
 339
 340         iio_device_unregister(indio_dev);
 341         iio_triggered_buffer_cleanup(indio_dev);
 342         if (st->reg)
 343                 regulator_disable(st->reg);
 344
 345         return 0;
 346 }
 347
 348 static const struct spi_device_id ad7887_id[] = {
 349         {"ad7887", ID_AD7887},
 350         {}
 351 };
 352 MODULE_DEVICE_TABLE(spi, ad7887_id);
 353
 354 static struct spi_driver ad7887_driver = {
 355         .driver = {
 356                 .name   = "ad7887",
 357         },
 358         .probe          = ad7887_probe,
 359         .remove         = ad7887_remove,
 360         .id_table       = ad7887_id,
 361 };
 362 module_spi_driver(ad7887_driver);
 363
 364 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 365 MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
 366 MODULE_LICENSE("GPL v2");