drivers/iio/adc/ad7476.c

   1 /*
   2  * AD7466/7/8 AD7476/5/7/8 (A) SPI ADC driver
   3  *
   4  * Copyright 2010 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/kernel.h>
  11 #include <linux/slab.h>
  12 #include <linux/sysfs.h>
  13 #include <linux/spi/spi.h>
  14 #include <linux/regulator/consumer.h>
  15 #include <linux/err.h>
  16 #include <linux/module.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 #include <linux/iio/trigger_consumer.h>
  23 #include <linux/iio/triggered_buffer.h>
  24
  25 struct ad7476_state;
  26
  27 struct ad7476_chip_info {
  28         unsigned int                    int_vref_uv;
  29         struct iio_chan_spec            channel[2];
  30         void (*reset)(struct ad7476_state *);
  31 };
  32
  33 struct ad7476_state {
  34         struct spi_device               *spi;
  35         const struct ad7476_chip_info   *chip_info;
  36         struct regulator                *reg;
  37         struct spi_transfer             xfer;
  38         struct spi_message              msg;
  39         /*
  40          * DMA (thus cache coherency maintenance) requires the
  41          * transfer buffers to live in their own cache lines.
  42          * Make the buffer large enough for one 16 bit sample and one 64 bit
  43          * aligned 64 bit timestamp.
  44          */
  45         unsigned char data[ALIGN(2, sizeof(s64)) + sizeof(s64)]
  46                         ____cacheline_aligned;
  47 };
  48
  49 enum ad7476_supported_device_ids {
  50         ID_AD7091R,
  51         ID_AD7276,
  52         ID_AD7277,
  53         ID_AD7278,
  54         ID_AD7466,
  55         ID_AD7467,
  56         ID_AD7468,
  57         ID_AD7495,
  58         ID_AD7940,
  59 };
  60
  61 static irqreturn_t ad7476_trigger_handler(int irq, void  *p)
  62 {
  63         struct iio_poll_func *pf = p;
  64         struct iio_dev *indio_dev = pf->indio_dev;
  65         struct ad7476_state *st = iio_priv(indio_dev);
  66         int b_sent;
  67
  68         b_sent = spi_sync(st->spi, &st->msg);
  69         if (b_sent < 0)
  70                 goto done;
  71
  72         iio_push_to_buffers_with_timestamp(indio_dev, st->data,
  73                 iio_get_time_ns());
  74 done:
  75         iio_trigger_notify_done(indio_dev->trig);
  76
  77         return IRQ_HANDLED;
  78 }
  79
  80 static void ad7091_reset(struct ad7476_state *st)
  81 {
  82         /* Any transfers with 8 scl cycles will reset the device */
  83         spi_read(st->spi, st->data, 1);
  84 }
  85
  86 static int ad7476_scan_direct(struct ad7476_state *st)
  87 {
  88         int ret;
  89
  90         ret = spi_sync(st->spi, &st->msg);
  91         if (ret)
  92                 return ret;
  93
  94         return be16_to_cpup((__be16 *)st->data);
  95 }
  96
  97 static int ad7476_read_raw(struct iio_dev *indio_dev,
  98                            struct iio_chan_spec const *chan,
  99                            int *val,
 100                            int *val2,
 101                            long m)
 102 {
 103         int ret;
 104         struct ad7476_state *st = iio_priv(indio_dev);
 105         int scale_uv;
 106
 107         switch (m) {
 108         case IIO_CHAN_INFO_RAW:
 109                 mutex_lock(&indio_dev->mlock);
 110                 if (iio_buffer_enabled(indio_dev))
 111                         ret = -EBUSY;
 112                 else
 113                         ret = ad7476_scan_direct(st);
 114                 mutex_unlock(&indio_dev->mlock);
 115
 116                 if (ret < 0)
 117                         return ret;
 118                 *val = (ret >> st->chip_info->channel[0].scan_type.shift) &
 119                         GENMASK(st->chip_info->channel[0].scan_type.realbits - 1, 0);
 120                 return IIO_VAL_INT;
 121         case IIO_CHAN_INFO_SCALE:
 122                 if (!st->chip_info->int_vref_uv) {
 123                         scale_uv = regulator_get_voltage(st->reg);
 124                         if (scale_uv < 0)
 125                                 return scale_uv;
 126                 } else {
 127                         scale_uv = st->chip_info->int_vref_uv;
 128                 }
 129                 *val = scale_uv / 1000;
 130                 *val2 = chan->scan_type.realbits;
 131                 return IIO_VAL_FRACTIONAL_LOG2;
 132         }
 133         return -EINVAL;
 134 }
 135
 136 #define _AD7476_CHAN(bits, _shift, _info_mask_sep)              \
 137         {                                                       \
 138         .type = IIO_VOLTAGE,                                    \
 139         .indexed = 1,                                           \
 140         .info_mask_separate = _info_mask_sep,                   \
 141         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
 142         .scan_type = {                                          \
 143                 .sign = 'u',                                    \
 144                 .realbits = (bits),                             \
 145                 .storagebits = 16,                              \
 146                 .shift = (_shift),                              \
 147                 .endianness = IIO_BE,                           \
 148         },                                                      \
 149 }
 150
 151 #define AD7476_CHAN(bits) _AD7476_CHAN((bits), 13 - (bits), \
 152                 BIT(IIO_CHAN_INFO_RAW))
 153 #define AD7940_CHAN(bits) _AD7476_CHAN((bits), 15 - (bits), \
 154                 BIT(IIO_CHAN_INFO_RAW))
 155 #define AD7091R_CHAN(bits) _AD7476_CHAN((bits), 16 - (bits), 0)
 156
 157 static const struct ad7476_chip_info ad7476_chip_info_tbl[] = {
 158         [ID_AD7091R] = {
 159                 .channel[0] = AD7091R_CHAN(12),
 160                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 161                 .reset = ad7091_reset,
 162         },
 163         [ID_AD7276] = {
 164                 .channel[0] = AD7940_CHAN(12),
 165                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 166         },
 167         [ID_AD7277] = {
 168                 .channel[0] = AD7940_CHAN(10),
 169                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 170         },
 171         [ID_AD7278] = {
 172                 .channel[0] = AD7940_CHAN(8),
 173                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 174         },
 175         [ID_AD7466] = {
 176                 .channel[0] = AD7476_CHAN(12),
 177                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 178         },
 179         [ID_AD7467] = {
 180                 .channel[0] = AD7476_CHAN(10),
 181                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 182         },
 183         [ID_AD7468] = {
 184                 .channel[0] = AD7476_CHAN(8),
 185                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 186         },
 187         [ID_AD7495] = {
 188                 .channel[0] = AD7476_CHAN(12),
 189                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 190                 .int_vref_uv = 2500000,
 191         },
 192         [ID_AD7940] = {
 193                 .channel[0] = AD7940_CHAN(14),
 194                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 195         },
 196 };
 197
 198 static const struct iio_info ad7476_info = {
 199         .driver_module = THIS_MODULE,
 200         .read_raw = &ad7476_read_raw,
 201 };
 202
 203 static int ad7476_probe(struct spi_device *spi)
 204 {
 205         struct ad7476_state *st;
 206         struct iio_dev *indio_dev;
 207         int ret;
 208
 209         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 210         if (!indio_dev)
 211                 return -ENOMEM;
 212
 213         st = iio_priv(indio_dev);
 214         st->chip_info =
 215                 &ad7476_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 216
 217         st->reg = devm_regulator_get(&spi->dev, "vcc");
 218         if (IS_ERR(st->reg))
 219                 return PTR_ERR(st->reg);
 220
 221         ret = regulator_enable(st->reg);
 222         if (ret)
 223                 return ret;
 224
 225         spi_set_drvdata(spi, indio_dev);
 226
 227         st->spi = spi;
 228
 229         /* Establish that the iio_dev is a child of the spi device */
 230         indio_dev->dev.parent = &spi->dev;
 231         indio_dev->name = spi_get_device_id(spi)->name;
 232         indio_dev->modes = INDIO_DIRECT_MODE;
 233         indio_dev->channels = st->chip_info->channel;
 234         indio_dev->num_channels = 2;
 235         indio_dev->info = &ad7476_info;
 236         /* Setup default message */
 237
 238         st->xfer.rx_buf = &st->data;
 239         st->xfer.len = st->chip_info->channel[0].scan_type.storagebits / 8;
 240
 241         spi_message_init(&st->msg);
 242         spi_message_add_tail(&st->xfer, &st->msg);
 243
 244         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 245                         &ad7476_trigger_handler, NULL);
 246         if (ret)
 247                 goto error_disable_reg;
 248
 249         if (st->chip_info->reset)
 250                 st->chip_info->reset(st);
 251
 252         ret = iio_device_register(indio_dev);
 253         if (ret)
 254                 goto error_ring_unregister;
 255         return 0;
 256
 257 error_ring_unregister:
 258         iio_triggered_buffer_cleanup(indio_dev);
 259 error_disable_reg:
 260         regulator_disable(st->reg);
 261
 262         return ret;
 263 }
 264
 265 static int ad7476_remove(struct spi_device *spi)
 266 {
 267         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 268         struct ad7476_state *st = iio_priv(indio_dev);
 269
 270         iio_device_unregister(indio_dev);
 271         iio_triggered_buffer_cleanup(indio_dev);
 272         regulator_disable(st->reg);
 273
 274         return 0;
 275 }
 276
 277 static const struct spi_device_id ad7476_id[] = {
 278         {"ad7091r", ID_AD7091R},
 279         {"ad7273", ID_AD7277},
 280         {"ad7274", ID_AD7276},
 281         {"ad7276", ID_AD7276},
 282         {"ad7277", ID_AD7277},
 283         {"ad7278", ID_AD7278},
 284         {"ad7466", ID_AD7466},
 285         {"ad7467", ID_AD7467},
 286         {"ad7468", ID_AD7468},
 287         {"ad7475", ID_AD7466},
 288         {"ad7476", ID_AD7466},
 289         {"ad7476a", ID_AD7466},
 290         {"ad7477", ID_AD7467},
 291         {"ad7477a", ID_AD7467},
 292         {"ad7478", ID_AD7468},
 293         {"ad7478a", ID_AD7468},
 294         {"ad7495", ID_AD7495},
 295         {"ad7910", ID_AD7467},
 296         {"ad7920", ID_AD7466},
 297         {"ad7940", ID_AD7940},
 298         {}
 299 };
 300 MODULE_DEVICE_TABLE(spi, ad7476_id);
 301
 302 static struct spi_driver ad7476_driver = {
 303         .driver = {
 304                 .name   = "ad7476",
 305                 .owner  = THIS_MODULE,
 306         },
 307         .probe          = ad7476_probe,
 308         .remove         = ad7476_remove,
 309         .id_table       = ad7476_id,
 310 };
 311 module_spi_driver(ad7476_driver);
 312
 313 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 314 MODULE_DESCRIPTION("Analog Devices AD7476 and similar 1-channel ADCs");
 315 MODULE_LICENSE("GPL v2");