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  * @channels:           channels specification
  47  * @num_channels:       number of channels
  48  * @dual_channels:      channels specification in dual mode
  49  * @num_dual_channels:  number of channels in dual mode
  50  */
  51 struct ad7887_chip_info {
  52         u16                             int_vref_mv;
  53         const struct iio_chan_spec      *channels;
  54         unsigned int                    num_channels;
  55         const struct iio_chan_spec      *dual_channels;
  56         unsigned int                    num_dual_channels;
  57 };
  58
  59 struct ad7887_state {
  60         struct spi_device               *spi;
  61         const struct ad7887_chip_info   *chip_info;
  62         struct regulator                *reg;
  63         struct spi_transfer             xfer[4];
  64         struct spi_message              msg[3];
  65         struct spi_message              *ring_msg;
  66         unsigned char                   tx_cmd_buf[4];
  67
  68         /*
  69          * DMA (thus cache coherency maintenance) requires the
  70          * transfer buffers to live in their own cache lines.
  71          * Buffer needs to be large enough to hold two 16 bit samples and a
  72          * 64 bit aligned 64 bit timestamp.
  73          */
  74         unsigned char data[ALIGN(4, sizeof(s64)) + sizeof(s64)]
  75                 ____cacheline_aligned;
  76 };
  77
  78 enum ad7887_supported_device_ids {
  79         ID_AD7887
  80 };
  81
  82 static int ad7887_ring_preenable(struct iio_dev *indio_dev)
  83 {
  84         struct ad7887_state *st = iio_priv(indio_dev);
  85
  86         /* We know this is a single long so can 'cheat' */
  87         switch (*indio_dev->active_scan_mask) {
  88         case (1 << 0):
  89                 st->ring_msg = &st->msg[AD7887_CH0];
  90                 break;
  91         case (1 << 1):
  92                 st->ring_msg = &st->msg[AD7887_CH1];
  93                 /* Dummy read: push CH1 setting down to hardware */
  94                 spi_sync(st->spi, st->ring_msg);
  95                 break;
  96         case ((1 << 1) | (1 << 0)):
  97                 st->ring_msg = &st->msg[AD7887_CH0_CH1];
  98                 break;
  99         }
 100
 101         return 0;
 102 }
 103
 104 static int ad7887_ring_postdisable(struct iio_dev *indio_dev)
 105 {
 106         struct ad7887_state *st = iio_priv(indio_dev);
 107
 108         /* dummy read: restore default CH0 settin */
 109         return spi_sync(st->spi, &st->msg[AD7887_CH0]);
 110 }
 111
 112 /*
 113  * ad7887_trigger_handler() bh of trigger launched polling to ring buffer
 114  *
 115  * Currently there is no option in this driver to disable the saving of
 116  * timestamps within the ring.
 117  **/
 118 static irqreturn_t ad7887_trigger_handler(int irq, void *p)
 119 {
 120         struct iio_poll_func *pf = p;
 121         struct iio_dev *indio_dev = pf->indio_dev;
 122         struct ad7887_state *st = iio_priv(indio_dev);
 123         int b_sent;
 124
 125         b_sent = spi_sync(st->spi, st->ring_msg);
 126         if (b_sent)
 127                 goto done;
 128
 129         iio_push_to_buffers_with_timestamp(indio_dev, st->data,
 130                 iio_get_time_ns(indio_dev));
 131 done:
 132         iio_trigger_notify_done(indio_dev->trig);
 133
 134         return IRQ_HANDLED;
 135 }
 136
 137 static const struct iio_buffer_setup_ops ad7887_ring_setup_ops = {
 138         .preenable = &ad7887_ring_preenable,
 139         .postdisable = &ad7887_ring_postdisable,
 140 };
 141
 142 static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
 143 {
 144         int ret = spi_sync(st->spi, &st->msg[ch]);
 145         if (ret)
 146                 return ret;
 147
 148         return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1];
 149 }
 150
 151 static int ad7887_read_raw(struct iio_dev *indio_dev,
 152                            struct iio_chan_spec const *chan,
 153                            int *val,
 154                            int *val2,
 155                            long m)
 156 {
 157         int ret;
 158         struct ad7887_state *st = iio_priv(indio_dev);
 159
 160         switch (m) {
 161         case IIO_CHAN_INFO_RAW:
 162                 ret = iio_device_claim_direct_mode(indio_dev);
 163                 if (ret)
 164                         return ret;
 165                 ret = ad7887_scan_direct(st, chan->address);
 166                 iio_device_release_direct_mode(indio_dev);
 167
 168                 if (ret < 0)
 169                         return ret;
 170                 *val = ret >> chan->scan_type.shift;
 171                 *val &= GENMASK(chan->scan_type.realbits - 1, 0);
 172                 return IIO_VAL_INT;
 173         case IIO_CHAN_INFO_SCALE:
 174                 if (st->reg) {
 175                         *val = regulator_get_voltage(st->reg);
 176                         if (*val < 0)
 177                                 return *val;
 178                         *val /= 1000;
 179                 } else {
 180                         *val = st->chip_info->int_vref_mv;
 181                 }
 182
 183                 *val2 = chan->scan_type.realbits;
 184
 185                 return IIO_VAL_FRACTIONAL_LOG2;
 186         }
 187         return -EINVAL;
 188 }
 189
 190 #define AD7887_CHANNEL(x) { \
 191         .type = IIO_VOLTAGE, \
 192         .indexed = 1, \
 193         .channel = (x), \
 194         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 195         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
 196         .address = (x), \
 197         .scan_index = (x), \
 198         .scan_type = { \
 199                 .sign = 'u', \
 200                 .realbits = 12, \
 201                 .storagebits = 16, \
 202                 .shift = 0, \
 203                 .endianness = IIO_BE, \
 204         }, \
 205 }
 206
 207 static const struct iio_chan_spec ad7887_channels[] = {
 208         AD7887_CHANNEL(0),
 209         IIO_CHAN_SOFT_TIMESTAMP(1),
 210 };
 211
 212 static const struct iio_chan_spec ad7887_dual_channels[] = {
 213         AD7887_CHANNEL(0),
 214         AD7887_CHANNEL(1),
 215         IIO_CHAN_SOFT_TIMESTAMP(2),
 216 };
 217
 218 static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
 219         /*
 220          * More devices added in future
 221          */
 222         [ID_AD7887] = {
 223                 .channels = ad7887_channels,
 224                 .num_channels = ARRAY_SIZE(ad7887_channels),
 225                 .dual_channels = ad7887_dual_channels,
 226                 .num_dual_channels = ARRAY_SIZE(ad7887_dual_channels),
 227                 .int_vref_mv = 2500,
 228         },
 229 };
 230
 231 static const struct iio_info ad7887_info = {
 232         .read_raw = &ad7887_read_raw,
 233 };
 234
 235 static void ad7887_reg_disable(void *data)
 236 {
 237         struct regulator *reg = data;
 238
 239         regulator_disable(reg);
 240 }
 241
 242 static int ad7887_probe(struct spi_device *spi)
 243 {
 244         struct ad7887_platform_data *pdata = spi->dev.platform_data;
 245         struct ad7887_state *st;
 246         struct iio_dev *indio_dev;
 247         uint8_t mode;
 248         int ret;
 249
 250         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 251         if (indio_dev == NULL)
 252                 return -ENOMEM;
 253
 254         st = iio_priv(indio_dev);
 255
 256         st->reg = devm_regulator_get_optional(&spi->dev, "vref");
 257         if (IS_ERR(st->reg)) {
 258                 if (PTR_ERR(st->reg) != -ENODEV)
 259                         return PTR_ERR(st->reg);
 260
 261                 st->reg = NULL;
 262         }
 263
 264         if (st->reg) {
 265                 ret = regulator_enable(st->reg);
 266                 if (ret)
 267                         return ret;
 268
 269                 ret = devm_add_action_or_reset(&spi->dev, ad7887_reg_disable, st->reg);
 270                 if (ret)
 271                         return ret;
 272         }
 273
 274         st->chip_info =
 275                 &ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 276
 277         spi_set_drvdata(spi, indio_dev);
 278         st->spi = spi;
 279
 280         indio_dev->name = spi_get_device_id(spi)->name;
 281         indio_dev->info = &ad7887_info;
 282         indio_dev->modes = INDIO_DIRECT_MODE;
 283
 284         /* Setup default message */
 285
 286         mode = AD7887_PM_MODE4;
 287         if (!st->reg)
 288                 mode |= AD7887_REF_DIS;
 289         if (pdata && pdata->en_dual)
 290                 mode |= AD7887_DUAL;
 291
 292         st->tx_cmd_buf[0] = AD7887_CH_AIN0 | mode;
 293
 294         st->xfer[0].rx_buf = &st->data[0];
 295         st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
 296         st->xfer[0].len = 2;
 297
 298         spi_message_init(&st->msg[AD7887_CH0]);
 299         spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);
 300
 301         if (pdata && pdata->en_dual) {
 302                 st->tx_cmd_buf[2] = AD7887_CH_AIN1 | mode;
 303
 304                 st->xfer[1].rx_buf = &st->data[0];
 305                 st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
 306                 st->xfer[1].len = 2;
 307
 308                 st->xfer[2].rx_buf = &st->data[2];
 309                 st->xfer[2].tx_buf = &st->tx_cmd_buf[0];
 310                 st->xfer[2].len = 2;
 311
 312                 spi_message_init(&st->msg[AD7887_CH0_CH1]);
 313                 spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
 314                 spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);
 315
 316                 st->xfer[3].rx_buf = &st->data[2];
 317                 st->xfer[3].tx_buf = &st->tx_cmd_buf[2];
 318                 st->xfer[3].len = 2;
 319
 320                 spi_message_init(&st->msg[AD7887_CH1]);
 321                 spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);
 322
 323                 indio_dev->channels = st->chip_info->dual_channels;
 324                 indio_dev->num_channels = st->chip_info->num_dual_channels;
 325         } else {
 326                 indio_dev->channels = st->chip_info->channels;
 327                 indio_dev->num_channels = st->chip_info->num_channels;
 328         }
 329
 330         ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
 331                         &iio_pollfunc_store_time,
 332                         &ad7887_trigger_handler, &ad7887_ring_setup_ops);
 333         if (ret)
 334                 return ret;
 335
 336         return devm_iio_device_register(&spi->dev, indio_dev);
 337 }
 338
 339 static const struct spi_device_id ad7887_id[] = {
 340         {"ad7887", ID_AD7887},
 341         {}
 342 };
 343 MODULE_DEVICE_TABLE(spi, ad7887_id);
 344
 345 static struct spi_driver ad7887_driver = {
 346         .driver = {
 347                 .name   = "ad7887",
 348         },
 349         .probe          = ad7887_probe,
 350         .id_table       = ad7887_id,
 351 };
 352 module_spi_driver(ad7887_driver);
 353
 354 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 355 MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
 356 MODULE_LICENSE("GPL v2");