drivers/iio/dac/ad5449.c

   1 /*
   2  * AD5415, AD5426, AD5429, AD5432, AD5439, AD5443, AD5449 Digital to Analog
   3  * Converter driver.
   4  *
   5  * Copyright 2012 Analog Devices Inc.
   6  *  Author: Lars-Peter Clausen <lars@metafoo.de>
   7  *
   8  * Licensed under the GPL-2.
   9  */
  10
  11 #include <linux/device.h>
  12 #include <linux/err.h>
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/spi/spi.h>
  16 #include <linux/slab.h>
  17 #include <linux/sysfs.h>
  18 #include <linux/regulator/consumer.h>
  19 #include <asm/unaligned.h>
  20
  21 #include <linux/iio/iio.h>
  22 #include <linux/iio/sysfs.h>
  23
  24 #include <linux/platform_data/ad5449.h>
  25
  26 #define AD5449_MAX_CHANNELS             2
  27 #define AD5449_MAX_VREFS                2
  28
  29 #define AD5449_CMD_NOOP                 0x0
  30 #define AD5449_CMD_LOAD_AND_UPDATE(x)   (0x1 + (x) * 3)
  31 #define AD5449_CMD_READ(x)              (0x2 + (x) * 3)
  32 #define AD5449_CMD_LOAD(x)              (0x3 + (x) * 3)
  33 #define AD5449_CMD_CTRL                 13
  34
  35 #define AD5449_CTRL_SDO_OFFSET          10
  36 #define AD5449_CTRL_DAISY_CHAIN         BIT(9)
  37 #define AD5449_CTRL_HCLR_TO_MIDSCALE    BIT(8)
  38 #define AD5449_CTRL_SAMPLE_RISING       BIT(7)
  39
  40 /**
  41  * struct ad5449_chip_info - chip specific information
  42  * @channels:           Channel specification
  43  * @num_channels:       Number of channels
  44  * @has_ctrl:           Chip has a control register
  45  */
  46 struct ad5449_chip_info {
  47         const struct iio_chan_spec *channels;
  48         unsigned int num_channels;
  49         bool has_ctrl;
  50 };
  51
  52 /**
  53  * struct ad5449 - driver instance specific data
  54  * @spi:                the SPI device for this driver instance
  55  * @chip_info:          chip model specific constants, available modes etc
  56  * @vref_reg:           vref supply regulators
  57  * @has_sdo:            whether the SDO line is connected
  58  * @dac_cache:          Cache for the DAC values
  59  * @data:               spi transfer buffers
  60  */
  61 struct ad5449 {
  62         struct spi_device               *spi;
  63         const struct ad5449_chip_info   *chip_info;
  64         struct regulator_bulk_data      vref_reg[AD5449_MAX_VREFS];
  65
  66         bool has_sdo;
  67         uint16_t dac_cache[AD5449_MAX_CHANNELS];
  68
  69         /*
  70          * DMA (thus cache coherency maintenance) requires the
  71          * transfer buffers to live in their own cache lines.
  72          */
  73         __be16 data[2] ____cacheline_aligned;
  74 };
  75
  76 enum ad5449_type {
  77         ID_AD5426,
  78         ID_AD5429,
  79         ID_AD5432,
  80         ID_AD5439,
  81         ID_AD5443,
  82         ID_AD5449,
  83 };
  84
  85 static int ad5449_write(struct iio_dev *indio_dev, unsigned int addr,
  86         unsigned int val)
  87 {
  88         struct ad5449 *st = iio_priv(indio_dev);
  89         int ret;
  90
  91         mutex_lock(&indio_dev->mlock);
  92         st->data[0] = cpu_to_be16((addr << 12) | val);
  93         ret = spi_write(st->spi, st->data, 2);
  94         mutex_unlock(&indio_dev->mlock);
  95
  96         return ret;
  97 }
  98
  99 static int ad5449_read(struct iio_dev *indio_dev, unsigned int addr,
 100         unsigned int *val)
 101 {
 102         struct ad5449 *st = iio_priv(indio_dev);
 103         int ret;
 104         struct spi_transfer t[] = {
 105                 {
 106                         .tx_buf = &st->data[0],
 107                         .len = 2,
 108                         .cs_change = 1,
 109                 }, {
 110                         .tx_buf = &st->data[1],
 111                         .rx_buf = &st->data[1],
 112                         .len = 2,
 113                 },
 114         };
 115
 116         mutex_lock(&indio_dev->mlock);
 117         st->data[0] = cpu_to_be16(addr << 12);
 118         st->data[1] = cpu_to_be16(AD5449_CMD_NOOP);
 119
 120         ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
 121         if (ret < 0)
 122                 goto out_unlock;
 123
 124         *val = be16_to_cpu(st->data[1]);
 125
 126 out_unlock:
 127         mutex_unlock(&indio_dev->mlock);
 128         return ret;
 129 }
 130
 131 static int ad5449_read_raw(struct iio_dev *indio_dev,
 132         struct iio_chan_spec const *chan, int *val, int *val2, long info)
 133 {
 134         struct ad5449 *st = iio_priv(indio_dev);
 135         struct regulator_bulk_data *reg;
 136         int scale_uv;
 137         int ret;
 138
 139         switch (info) {
 140         case IIO_CHAN_INFO_RAW:
 141                 if (st->has_sdo) {
 142                         ret = ad5449_read(indio_dev,
 143                                 AD5449_CMD_READ(chan->address), val);
 144                         if (ret)
 145                                 return ret;
 146                         *val &= 0xfff;
 147                 } else {
 148                         *val = st->dac_cache[chan->address];
 149                 }
 150
 151                 return IIO_VAL_INT;
 152         case IIO_CHAN_INFO_SCALE:
 153                 reg = &st->vref_reg[chan->channel];
 154                 scale_uv = regulator_get_voltage(reg->consumer);
 155                 if (scale_uv < 0)
 156                         return scale_uv;
 157
 158                 *val = scale_uv / 1000;
 159                 *val2 = chan->scan_type.realbits;
 160
 161                 return IIO_VAL_FRACTIONAL_LOG2;
 162         default:
 163                 break;
 164         }
 165
 166         return -EINVAL;
 167 }
 168
 169 static int ad5449_write_raw(struct iio_dev *indio_dev,
 170         struct iio_chan_spec const *chan, int val, int val2, long info)
 171 {
 172         struct ad5449 *st = iio_priv(indio_dev);
 173         int ret;
 174
 175         switch (info) {
 176         case IIO_CHAN_INFO_RAW:
 177                 if (val < 0 || val >= (1 << chan->scan_type.realbits))
 178                         return -EINVAL;
 179
 180                 ret = ad5449_write(indio_dev,
 181                         AD5449_CMD_LOAD_AND_UPDATE(chan->address),
 182                         val << chan->scan_type.shift);
 183                 if (ret == 0)
 184                         st->dac_cache[chan->address] = val;
 185                 break;
 186         default:
 187                 ret = -EINVAL;
 188         }
 189
 190         return ret;
 191 }
 192
 193 static const struct iio_info ad5449_info = {
 194         .read_raw = ad5449_read_raw,
 195         .write_raw = ad5449_write_raw,
 196         .driver_module = THIS_MODULE,
 197 };
 198
 199 #define AD5449_CHANNEL(chan, bits) {                            \
 200         .type = IIO_VOLTAGE,                                    \
 201         .indexed = 1,                                           \
 202         .output = 1,                                            \
 203         .channel = (chan),                                      \
 204         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |          \
 205                 BIT(IIO_CHAN_INFO_SCALE),                       \
 206         .address = (chan),                                      \
 207         .scan_type = {                                          \
 208                 .sign = 'u',                                    \
 209                 .realbits = (bits),                             \
 210                 .storagebits = 16,                              \
 211                 .shift = 12 - (bits),                           \
 212         },                                                      \
 213 }
 214
 215 #define DECLARE_AD5449_CHANNELS(name, bits) \
 216 const struct iio_chan_spec name[] = { \
 217         AD5449_CHANNEL(0, bits), \
 218         AD5449_CHANNEL(1, bits), \
 219 }
 220
 221 static DECLARE_AD5449_CHANNELS(ad5429_channels, 8);
 222 static DECLARE_AD5449_CHANNELS(ad5439_channels, 10);
 223 static DECLARE_AD5449_CHANNELS(ad5449_channels, 12);
 224
 225 static const struct ad5449_chip_info ad5449_chip_info[] = {
 226         [ID_AD5426] = {
 227                 .channels = ad5429_channels,
 228                 .num_channels = 1,
 229                 .has_ctrl = false,
 230         },
 231         [ID_AD5429] = {
 232                 .channels = ad5429_channels,
 233                 .num_channels = 2,
 234                 .has_ctrl = true,
 235         },
 236         [ID_AD5432] = {
 237                 .channels = ad5439_channels,
 238                 .num_channels = 1,
 239                 .has_ctrl = false,
 240         },
 241         [ID_AD5439] = {
 242                 .channels = ad5439_channels,
 243                 .num_channels = 2,
 244                 .has_ctrl = true,
 245         },
 246         [ID_AD5443] = {
 247                 .channels = ad5449_channels,
 248                 .num_channels = 1,
 249                 .has_ctrl = false,
 250         },
 251         [ID_AD5449] = {
 252                 .channels = ad5449_channels,
 253                 .num_channels = 2,
 254                 .has_ctrl = true,
 255         },
 256 };
 257
 258 static const char *ad5449_vref_name(struct ad5449 *st, int n)
 259 {
 260         if (st->chip_info->num_channels == 1)
 261                 return "VREF";
 262
 263         if (n == 0)
 264                 return "VREFA";
 265         else
 266                 return "VREFB";
 267 }
 268
 269 static int ad5449_spi_probe(struct spi_device *spi)
 270 {
 271         struct ad5449_platform_data *pdata = spi->dev.platform_data;
 272         const struct spi_device_id *id = spi_get_device_id(spi);
 273         struct iio_dev *indio_dev;
 274         struct ad5449 *st;
 275         unsigned int i;
 276         int ret;
 277
 278         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 279         if (indio_dev == NULL)
 280                 return -ENOMEM;
 281
 282         st = iio_priv(indio_dev);
 283         spi_set_drvdata(spi, indio_dev);
 284
 285         st->chip_info = &ad5449_chip_info[id->driver_data];
 286         st->spi = spi;
 287
 288         for (i = 0; i < st->chip_info->num_channels; ++i)
 289                 st->vref_reg[i].supply = ad5449_vref_name(st, i);
 290
 291         ret = devm_regulator_bulk_get(&spi->dev, st->chip_info->num_channels,
 292                                 st->vref_reg);
 293         if (ret)
 294                 return ret;
 295
 296         ret = regulator_bulk_enable(st->chip_info->num_channels, st->vref_reg);
 297         if (ret)
 298                 return ret;
 299
 300         indio_dev->dev.parent = &spi->dev;
 301         indio_dev->name = id->name;
 302         indio_dev->info = &ad5449_info;
 303         indio_dev->modes = INDIO_DIRECT_MODE;
 304         indio_dev->channels = st->chip_info->channels;
 305         indio_dev->num_channels = st->chip_info->num_channels;
 306
 307         if (st->chip_info->has_ctrl) {
 308                 unsigned int ctrl = 0x00;
 309                 if (pdata) {
 310                         if (pdata->hardware_clear_to_midscale)
 311                                 ctrl |= AD5449_CTRL_HCLR_TO_MIDSCALE;
 312                         ctrl |= pdata->sdo_mode << AD5449_CTRL_SDO_OFFSET;
 313                         st->has_sdo = pdata->sdo_mode != AD5449_SDO_DISABLED;
 314                 } else {
 315                         st->has_sdo = true;
 316                 }
 317                 ad5449_write(indio_dev, AD5449_CMD_CTRL, ctrl);
 318         }
 319
 320         ret = iio_device_register(indio_dev);
 321         if (ret)
 322                 goto error_disable_reg;
 323
 324         return 0;
 325
 326 error_disable_reg:
 327         regulator_bulk_disable(st->chip_info->num_channels, st->vref_reg);
 328
 329         return ret;
 330 }
 331
 332 static int ad5449_spi_remove(struct spi_device *spi)
 333 {
 334         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 335         struct ad5449 *st = iio_priv(indio_dev);
 336
 337         iio_device_unregister(indio_dev);
 338
 339         regulator_bulk_disable(st->chip_info->num_channels, st->vref_reg);
 340
 341         return 0;
 342 }
 343
 344 static const struct spi_device_id ad5449_spi_ids[] = {
 345         { "ad5415", ID_AD5449 },
 346         { "ad5426", ID_AD5426 },
 347         { "ad5429", ID_AD5429 },
 348         { "ad5432", ID_AD5432 },
 349         { "ad5439", ID_AD5439 },
 350         { "ad5443", ID_AD5443 },
 351         { "ad5449", ID_AD5449 },
 352         {}
 353 };
 354 MODULE_DEVICE_TABLE(spi, ad5449_spi_ids);
 355
 356 static struct spi_driver ad5449_spi_driver = {
 357         .driver = {
 358                 .name = "ad5449",
 359         },
 360         .probe = ad5449_spi_probe,
 361         .remove = ad5449_spi_remove,
 362         .id_table = ad5449_spi_ids,
 363 };
 364 module_spi_driver(ad5449_spi_driver);
 365
 366 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 367 MODULE_DESCRIPTION("Analog Devices AD5449 and similar DACs");
 368 MODULE_LICENSE("GPL v2");