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         s64 time_ns;
  68         int b_sent;
  69
  70         b_sent = spi_sync(st->spi, &st->msg);
  71         if (b_sent < 0)
  72                 goto done;
  73
  74         time_ns = iio_get_time_ns();
  75
  76         if (indio_dev->scan_timestamp)
  77                 ((s64 *)st->data)[1] = time_ns;
  78
  79         iio_push_to_buffers(indio_dev, st->data);
  80 done:
  81         iio_trigger_notify_done(indio_dev->trig);
  82
  83         return IRQ_HANDLED;
  84 }
  85
  86 static void ad7091_reset(struct ad7476_state *st)
  87 {
  88         /* Any transfers with 8 scl cycles will reset the device */
  89         spi_read(st->spi, st->data, 1);
  90 }
  91
  92 static int ad7476_scan_direct(struct ad7476_state *st)
  93 {
  94         int ret;
  95
  96         ret = spi_sync(st->spi, &st->msg);
  97         if (ret)
  98                 return ret;
  99
 100         return be16_to_cpup((__be16 *)st->data);
 101 }
 102
 103 static int ad7476_read_raw(struct iio_dev *indio_dev,
 104                            struct iio_chan_spec const *chan,
 105                            int *val,
 106                            int *val2,
 107                            long m)
 108 {
 109         int ret;
 110         struct ad7476_state *st = iio_priv(indio_dev);
 111         int scale_uv;
 112
 113         switch (m) {
 114         case IIO_CHAN_INFO_RAW:
 115                 mutex_lock(&indio_dev->mlock);
 116                 if (iio_buffer_enabled(indio_dev))
 117                         ret = -EBUSY;
 118                 else
 119                         ret = ad7476_scan_direct(st);
 120                 mutex_unlock(&indio_dev->mlock);
 121
 122                 if (ret < 0)
 123                         return ret;
 124                 *val = (ret >> st->chip_info->channel[0].scan_type.shift) &
 125                         RES_MASK(st->chip_info->channel[0].scan_type.realbits);
 126                 return IIO_VAL_INT;
 127         case IIO_CHAN_INFO_SCALE:
 128                 if (!st->chip_info->int_vref_uv) {
 129                         scale_uv = regulator_get_voltage(st->reg);
 130                         if (scale_uv < 0)
 131                                 return scale_uv;
 132                 } else {
 133                         scale_uv = st->chip_info->int_vref_uv;
 134                 }
 135                 scale_uv >>= chan->scan_type.realbits;
 136                 *val =  scale_uv / 1000;
 137                 *val2 = (scale_uv % 1000) * 1000;
 138                 return IIO_VAL_INT_PLUS_MICRO;
 139         }
 140         return -EINVAL;
 141 }
 142
 143 #define _AD7476_CHAN(bits, _shift, _info_mask)                  \
 144         {                                                       \
 145         .type = IIO_VOLTAGE,                                    \
 146         .indexed = 1,                                           \
 147         .info_mask = _info_mask |                               \
 148         IIO_CHAN_INFO_SCALE_SHARED_BIT,                         \
 149         .scan_type = {                                          \
 150                 .sign = 'u',                                    \
 151                 .realbits = (bits),                             \
 152                 .storagebits = 16,                              \
 153                 .shift = (_shift),                              \
 154                 .endianness = IIO_BE,                           \
 155         },                                                      \
 156 }
 157
 158 #define AD7476_CHAN(bits) _AD7476_CHAN((bits), 13 - (bits), \
 159                 IIO_CHAN_INFO_RAW_SEPARATE_BIT)
 160 #define AD7940_CHAN(bits) _AD7476_CHAN((bits), 15 - (bits), \
 161                 IIO_CHAN_INFO_RAW_SEPARATE_BIT)
 162 #define AD7091R_CHAN(bits) _AD7476_CHAN((bits), 16 - (bits), 0)
 163
 164 static const struct ad7476_chip_info ad7476_chip_info_tbl[] = {
 165         [ID_AD7091R] = {
 166                 .channel[0] = AD7091R_CHAN(12),
 167                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 168                 .reset = ad7091_reset,
 169         },
 170         [ID_AD7276] = {
 171                 .channel[0] = AD7940_CHAN(12),
 172                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 173         },
 174         [ID_AD7277] = {
 175                 .channel[0] = AD7940_CHAN(10),
 176                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 177         },
 178         [ID_AD7278] = {
 179                 .channel[0] = AD7940_CHAN(8),
 180                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 181         },
 182         [ID_AD7466] = {
 183                 .channel[0] = AD7476_CHAN(12),
 184                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 185         },
 186         [ID_AD7467] = {
 187                 .channel[0] = AD7476_CHAN(10),
 188                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 189         },
 190         [ID_AD7468] = {
 191                 .channel[0] = AD7476_CHAN(8),
 192                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 193         },
 194         [ID_AD7495] = {
 195                 .channel[0] = AD7476_CHAN(12),
 196                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 197                 .int_vref_uv = 2500000,
 198         },
 199         [ID_AD7940] = {
 200                 .channel[0] = AD7940_CHAN(14),
 201                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 202         },
 203 };
 204
 205 static const struct iio_info ad7476_info = {
 206         .driver_module = THIS_MODULE,
 207         .read_raw = &ad7476_read_raw,
 208 };
 209
 210 static int ad7476_probe(struct spi_device *spi)
 211 {
 212         struct ad7476_state *st;
 213         struct iio_dev *indio_dev;
 214         int ret;
 215
 216         indio_dev = iio_device_alloc(sizeof(*st));
 217         if (indio_dev == NULL) {
 218                 ret = -ENOMEM;
 219                 goto error_ret;
 220         }
 221         st = iio_priv(indio_dev);
 222         st->chip_info =
 223                 &ad7476_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 224
 225         st->reg = regulator_get(&spi->dev, "vcc");
 226         if (IS_ERR(st->reg)) {
 227                 ret = PTR_ERR(st->reg);
 228                 goto error_free_dev;
 229         }
 230
 231         ret = regulator_enable(st->reg);
 232         if (ret)
 233                 goto error_put_reg;
 234
 235         spi_set_drvdata(spi, indio_dev);
 236
 237         st->spi = spi;
 238
 239         /* Establish that the iio_dev is a child of the spi device */
 240         indio_dev->dev.parent = &spi->dev;
 241         indio_dev->name = spi_get_device_id(spi)->name;
 242         indio_dev->modes = INDIO_DIRECT_MODE;
 243         indio_dev->channels = st->chip_info->channel;
 244         indio_dev->num_channels = 2;
 245         indio_dev->info = &ad7476_info;
 246         /* Setup default message */
 247
 248         st->xfer.rx_buf = &st->data;
 249         st->xfer.len = st->chip_info->channel[0].scan_type.storagebits / 8;
 250
 251         spi_message_init(&st->msg);
 252         spi_message_add_tail(&st->xfer, &st->msg);
 253
 254         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 255                         &ad7476_trigger_handler, NULL);
 256         if (ret)
 257                 goto error_disable_reg;
 258
 259         if (st->chip_info->reset)
 260                 st->chip_info->reset(st);
 261
 262         ret = iio_device_register(indio_dev);
 263         if (ret)
 264                 goto error_ring_unregister;
 265         return 0;
 266
 267 error_ring_unregister:
 268         iio_triggered_buffer_cleanup(indio_dev);
 269 error_disable_reg:
 270         regulator_disable(st->reg);
 271 error_put_reg:
 272         regulator_put(st->reg);
 273 error_free_dev:
 274         iio_device_free(indio_dev);
 275
 276 error_ret:
 277         return ret;
 278 }
 279
 280 static int ad7476_remove(struct spi_device *spi)
 281 {
 282         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 283         struct ad7476_state *st = iio_priv(indio_dev);
 284
 285         iio_device_unregister(indio_dev);
 286         iio_triggered_buffer_cleanup(indio_dev);
 287         regulator_disable(st->reg);
 288         regulator_put(st->reg);
 289         iio_device_free(indio_dev);
 290
 291         return 0;
 292 }
 293
 294 static const struct spi_device_id ad7476_id[] = {
 295         {"ad7091r", ID_AD7091R},
 296         {"ad7273", ID_AD7277},
 297         {"ad7274", ID_AD7276},
 298         {"ad7276", ID_AD7276},
 299         {"ad7277", ID_AD7277},
 300         {"ad7278", ID_AD7278},
 301         {"ad7466", ID_AD7466},
 302         {"ad7467", ID_AD7467},
 303         {"ad7468", ID_AD7468},
 304         {"ad7475", ID_AD7466},
 305         {"ad7476", ID_AD7466},
 306         {"ad7476a", ID_AD7466},
 307         {"ad7477", ID_AD7467},
 308         {"ad7477a", ID_AD7467},
 309         {"ad7478", ID_AD7468},
 310         {"ad7478a", ID_AD7468},
 311         {"ad7495", ID_AD7495},
 312         {"ad7910", ID_AD7467},
 313         {"ad7920", ID_AD7466},
 314         {"ad7940", ID_AD7940},
 315         {}
 316 };
 317 MODULE_DEVICE_TABLE(spi, ad7476_id);
 318
 319 static struct spi_driver ad7476_driver = {
 320         .driver = {
 321                 .name   = "ad7476",
 322                 .owner  = THIS_MODULE,
 323         },
 324         .probe          = ad7476_probe,
 325         .remove         = ad7476_remove,
 326         .id_table       = ad7476_id,
 327 };
 328 module_spi_driver(ad7476_driver);
 329
 330 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 331 MODULE_DESCRIPTION("Analog Devices AD7476 and similar 1-channel ADCs");
 332 MODULE_LICENSE("GPL v2");