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