drivers/iio/adc/ad7923.c

   1 /*
   2  * AD7904/AD7914/AD7923/AD7924 SPI ADC driver
   3  *
   4  * Copyright 2011 Analog Devices Inc (from AD7923 Driver)
   5  * Copyright 2012 CS Systemes d'Information
   6  *
   7  * Licensed under the GPL-2.
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/sysfs.h>
  14 #include <linux/spi/spi.h>
  15 #include <linux/regulator/consumer.h>
  16 #include <linux/err.h>
  17 #include <linux/delay.h>
  18 #include <linux/module.h>
  19 #include <linux/interrupt.h>
  20
  21 #include <linux/iio/iio.h>
  22 #include <linux/iio/sysfs.h>
  23 #include <linux/iio/buffer.h>
  24 #include <linux/iio/trigger_consumer.h>
  25 #include <linux/iio/triggered_buffer.h>
  26
  27 #define AD7923_WRITE_CR         (1 << 11)       /* write control register */
  28 #define AD7923_RANGE            (1 << 1)        /* range to REFin */
  29 #define AD7923_CODING           (1 << 0)        /* coding is straight binary */
  30 #define AD7923_PM_MODE_AS       (1)             /* auto shutdown */
  31 #define AD7923_PM_MODE_FS       (2)             /* full shutdown */
  32 #define AD7923_PM_MODE_OPS      (3)             /* normal operation */
  33 #define AD7923_CHANNEL_0        (0)             /* analog input 0 */
  34 #define AD7923_CHANNEL_1        (1)             /* analog input 1 */
  35 #define AD7923_CHANNEL_2        (2)             /* analog input 2 */
  36 #define AD7923_CHANNEL_3        (3)             /* analog input 3 */
  37 #define AD7923_SEQUENCE_OFF     (0)             /* no sequence fonction */
  38 #define AD7923_SEQUENCE_PROTECT (2)             /* no interrupt write cycle */
  39 #define AD7923_SEQUENCE_ON      (3)             /* continuous sequence */
  40
  41 #define AD7923_MAX_CHAN         4
  42
  43 #define AD7923_PM_MODE_WRITE(mode)      (mode << 4)     /* write mode */
  44 #define AD7923_CHANNEL_WRITE(channel)   (channel << 6)  /* write channel */
  45 #define AD7923_SEQUENCE_WRITE(sequence) (((sequence & 1) << 3) \
  46                                         + ((sequence & 2) << 9))
  47                                                 /* write sequence fonction */
  48 /* left shift for CR : bit 11 transmit in first */
  49 #define AD7923_SHIFT_REGISTER   4
  50
  51 /* val = value, dec = left shift, bits = number of bits of the mask */
  52 #define EXTRACT(val, dec, bits)         ((val >> dec) & ((1 << bits) - 1))
  53
  54 struct ad7923_state {
  55         struct spi_device               *spi;
  56         struct spi_transfer             ring_xfer[5];
  57         struct spi_transfer             scan_single_xfer[2];
  58         struct spi_message              ring_msg;
  59         struct spi_message              scan_single_msg;
  60
  61         struct regulator                *reg;
  62
  63         unsigned int                    settings;
  64
  65         /*
  66          * DMA (thus cache coherency maintenance) requires the
  67          * transfer buffers to live in their own cache lines.
  68          */
  69         __be16                          rx_buf[4] ____cacheline_aligned;
  70         __be16                          tx_buf[4];
  71 };
  72
  73 struct ad7923_chip_info {
  74         const struct iio_chan_spec *channels;
  75         unsigned int num_channels;
  76 };
  77
  78 enum ad7923_id {
  79         AD7904,
  80         AD7914,
  81         AD7924,
  82 };
  83
  84 #define AD7923_V_CHAN(index, bits)                                      \
  85         {                                                               \
  86                 .type = IIO_VOLTAGE,                                    \
  87                 .indexed = 1,                                           \
  88                 .channel = index,                                       \
  89                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  90                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  91                 .address = index,                                       \
  92                 .scan_index = index,                                    \
  93                 .scan_type = {                                          \
  94                         .sign = 'u',                                    \
  95                         .realbits = (bits),                             \
  96                         .storagebits = 16,                              \
  97                         .endianness = IIO_BE,                           \
  98                 },                                                      \
  99         }
 100
 101 #define DECLARE_AD7923_CHANNELS(name, bits) \
 102 const struct iio_chan_spec name ## _channels[] = { \
 103         AD7923_V_CHAN(0, bits), \
 104         AD7923_V_CHAN(1, bits), \
 105         AD7923_V_CHAN(2, bits), \
 106         AD7923_V_CHAN(3, bits), \
 107         IIO_CHAN_SOFT_TIMESTAMP(4), \
 108 }
 109
 110 static DECLARE_AD7923_CHANNELS(ad7904, 8);
 111 static DECLARE_AD7923_CHANNELS(ad7914, 10);
 112 static DECLARE_AD7923_CHANNELS(ad7924, 12);
 113
 114 static const struct ad7923_chip_info ad7923_chip_info[] = {
 115         [AD7904] = {
 116                 .channels = ad7904_channels,
 117                 .num_channels = ARRAY_SIZE(ad7904_channels),
 118         },
 119         [AD7914] = {
 120                 .channels = ad7914_channels,
 121                 .num_channels = ARRAY_SIZE(ad7914_channels),
 122         },
 123         [AD7924] = {
 124                 .channels = ad7924_channels,
 125                 .num_channels = ARRAY_SIZE(ad7924_channels),
 126         },
 127 };
 128
 129 /**
 130  * ad7923_update_scan_mode() setup the spi transfer buffer for the new scan mask
 131  **/
 132 static int ad7923_update_scan_mode(struct iio_dev *indio_dev,
 133         const unsigned long *active_scan_mask)
 134 {
 135         struct ad7923_state *st = iio_priv(indio_dev);
 136         int i, cmd, len;
 137
 138         len = 0;
 139         for_each_set_bit(i, active_scan_mask, AD7923_MAX_CHAN) {
 140                 cmd = AD7923_WRITE_CR | AD7923_CHANNEL_WRITE(i) |
 141                         AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) |
 142                         st->settings;
 143                 cmd <<= AD7923_SHIFT_REGISTER;
 144                 st->tx_buf[len++] = cpu_to_be16(cmd);
 145         }
 146         /* build spi ring message */
 147         st->ring_xfer[0].tx_buf = &st->tx_buf[0];
 148         st->ring_xfer[0].len = len;
 149         st->ring_xfer[0].cs_change = 1;
 150
 151         spi_message_init(&st->ring_msg);
 152         spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);
 153
 154         for (i = 0; i < len; i++) {
 155                 st->ring_xfer[i + 1].rx_buf = &st->rx_buf[i];
 156                 st->ring_xfer[i + 1].len = 2;
 157                 st->ring_xfer[i + 1].cs_change = 1;
 158                 spi_message_add_tail(&st->ring_xfer[i + 1], &st->ring_msg);
 159         }
 160         /* make sure last transfer cs_change is not set */
 161         st->ring_xfer[i + 1].cs_change = 0;
 162
 163         return 0;
 164 }
 165
 166 /**
 167  * ad7923_trigger_handler() bh of trigger launched polling to ring buffer
 168  *
 169  * Currently there is no option in this driver to disable the saving of
 170  * timestamps within the ring.
 171  **/
 172 static irqreturn_t ad7923_trigger_handler(int irq, void *p)
 173 {
 174         struct iio_poll_func *pf = p;
 175         struct iio_dev *indio_dev = pf->indio_dev;
 176         struct ad7923_state *st = iio_priv(indio_dev);
 177         int b_sent;
 178
 179         b_sent = spi_sync(st->spi, &st->ring_msg);
 180         if (b_sent)
 181                 goto done;
 182
 183         iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf,
 184                 iio_get_time_ns(indio_dev));
 185
 186 done:
 187         iio_trigger_notify_done(indio_dev->trig);
 188
 189         return IRQ_HANDLED;
 190 }
 191
 192 static int ad7923_scan_direct(struct ad7923_state *st, unsigned ch)
 193 {
 194         int ret, cmd;
 195
 196         cmd = AD7923_WRITE_CR | AD7923_CHANNEL_WRITE(ch) |
 197                 AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) |
 198                 st->settings;
 199         cmd <<= AD7923_SHIFT_REGISTER;
 200         st->tx_buf[0] = cpu_to_be16(cmd);
 201
 202         ret = spi_sync(st->spi, &st->scan_single_msg);
 203         if (ret)
 204                 return ret;
 205
 206         return be16_to_cpu(st->rx_buf[0]);
 207 }
 208
 209 static int ad7923_get_range(struct ad7923_state *st)
 210 {
 211         int vref;
 212
 213         vref = regulator_get_voltage(st->reg);
 214         if (vref < 0)
 215                 return vref;
 216
 217         vref /= 1000;
 218
 219         if (!(st->settings & AD7923_RANGE))
 220                 vref *= 2;
 221
 222         return vref;
 223 }
 224
 225 static int ad7923_read_raw(struct iio_dev *indio_dev,
 226                            struct iio_chan_spec const *chan,
 227                            int *val,
 228                            int *val2,
 229                            long m)
 230 {
 231         int ret;
 232         struct ad7923_state *st = iio_priv(indio_dev);
 233
 234         switch (m) {
 235         case IIO_CHAN_INFO_RAW:
 236                 ret = iio_device_claim_direct_mode(indio_dev);
 237                 if (ret)
 238                         return ret;
 239                 ret = ad7923_scan_direct(st, chan->address);
 240                 iio_device_release_direct_mode(indio_dev);
 241
 242                 if (ret < 0)
 243                         return ret;
 244
 245                 if (chan->address == EXTRACT(ret, 12, 4))
 246                         *val = EXTRACT(ret, 0, 12);
 247                 else
 248                         return -EIO;
 249
 250                 return IIO_VAL_INT;
 251         case IIO_CHAN_INFO_SCALE:
 252                 ret = ad7923_get_range(st);
 253                 if (ret < 0)
 254                         return ret;
 255                 *val = ret;
 256                 *val2 = chan->scan_type.realbits;
 257                 return IIO_VAL_FRACTIONAL_LOG2;
 258         }
 259         return -EINVAL;
 260 }
 261
 262 static const struct iio_info ad7923_info = {
 263         .read_raw = &ad7923_read_raw,
 264         .update_scan_mode = ad7923_update_scan_mode,
 265         .driver_module = THIS_MODULE,
 266 };
 267
 268 static int ad7923_probe(struct spi_device *spi)
 269 {
 270         struct ad7923_state *st;
 271         struct iio_dev *indio_dev;
 272         const struct ad7923_chip_info *info;
 273         int ret;
 274
 275         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 276         if (indio_dev == NULL)
 277                 return -ENOMEM;
 278
 279         st = iio_priv(indio_dev);
 280
 281         spi_set_drvdata(spi, indio_dev);
 282
 283         st->spi = spi;
 284         st->settings = AD7923_CODING | AD7923_RANGE |
 285                         AD7923_PM_MODE_WRITE(AD7923_PM_MODE_OPS);
 286
 287         info = &ad7923_chip_info[spi_get_device_id(spi)->driver_data];
 288
 289         indio_dev->name = spi_get_device_id(spi)->name;
 290         indio_dev->dev.parent = &spi->dev;
 291         indio_dev->dev.of_node = spi->dev.of_node;
 292         indio_dev->modes = INDIO_DIRECT_MODE;
 293         indio_dev->channels = info->channels;
 294         indio_dev->num_channels = info->num_channels;
 295         indio_dev->info = &ad7923_info;
 296
 297         /* Setup default message */
 298
 299         st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
 300         st->scan_single_xfer[0].len = 2;
 301         st->scan_single_xfer[0].cs_change = 1;
 302         st->scan_single_xfer[1].rx_buf = &st->rx_buf[0];
 303         st->scan_single_xfer[1].len = 2;
 304
 305         spi_message_init(&st->scan_single_msg);
 306         spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
 307         spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
 308
 309         st->reg = devm_regulator_get(&spi->dev, "refin");
 310         if (IS_ERR(st->reg))
 311                 return PTR_ERR(st->reg);
 312
 313         ret = regulator_enable(st->reg);
 314         if (ret)
 315                 return ret;
 316
 317         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 318                         &ad7923_trigger_handler, NULL);
 319         if (ret)
 320                 goto error_disable_reg;
 321
 322         ret = iio_device_register(indio_dev);
 323         if (ret)
 324                 goto error_cleanup_ring;
 325
 326         return 0;
 327
 328 error_cleanup_ring:
 329         iio_triggered_buffer_cleanup(indio_dev);
 330 error_disable_reg:
 331         regulator_disable(st->reg);
 332
 333         return ret;
 334 }
 335
 336 static int ad7923_remove(struct spi_device *spi)
 337 {
 338         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 339         struct ad7923_state *st = iio_priv(indio_dev);
 340
 341         iio_device_unregister(indio_dev);
 342         iio_triggered_buffer_cleanup(indio_dev);
 343         regulator_disable(st->reg);
 344
 345         return 0;
 346 }
 347
 348 static const struct spi_device_id ad7923_id[] = {
 349         {"ad7904", AD7904},
 350         {"ad7914", AD7914},
 351         {"ad7923", AD7924},
 352         {"ad7924", AD7924},
 353         {}
 354 };
 355 MODULE_DEVICE_TABLE(spi, ad7923_id);
 356
 357 static struct spi_driver ad7923_driver = {
 358         .driver = {
 359                 .name   = "ad7923",
 360         },
 361         .probe          = ad7923_probe,
 362         .remove         = ad7923_remove,
 363         .id_table       = ad7923_id,
 364 };
 365 module_spi_driver(ad7923_driver);
 366
 367 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 368 MODULE_AUTHOR("Patrick Vasseur <patrick.vasseur@c-s.fr>");
 369 MODULE_DESCRIPTION("Analog Devices AD7904/AD7914/AD7923/AD7924 ADC");
 370 MODULE_LICENSE("GPL v2");