drivers/iio/adc/mcp320x.c

   1 /*
   2  * Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
   3  * Copyright (C) 2014 Rose Technology
   4  *         Allan Bendorff Jensen <abj@rosetechnology.dk>
   5  *         Soren Andersen <san@rosetechnology.dk>
   6  *
   7  * Driver for following ADC chips from Microchip Technology's:
   8  * 10 Bit converter
   9  * MCP3001
  10  * MCP3002
  11  * MCP3004
  12  * MCP3008
  13  * ------------
  14  * 12 bit converter
  15  * MCP3201
  16  * MCP3202
  17  * MCP3204
  18  * MCP3208
  19  * ------------
  20  *
  21  * Datasheet can be found here:
  22  * http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf  mcp3001
  23  * http://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf  mcp3002
  24  * http://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf  mcp3004/08
  25  * http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf  mcp3201
  26  * http://ww1.microchip.com/downloads/en/DeviceDoc/21034D.pdf  mcp3202
  27  * http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf  mcp3204/08
  28  * http://ww1.microchip.com/downloads/en/DeviceDoc/21700E.pdf  mcp3301
  29  *
  30  * This program is free software; you can redistribute it and/or modify
  31  * it under the terms of the GNU General Public License version 2 as
  32  * published by the Free Software Foundation.
  33  */
  34
  35 #include <linux/err.h>
  36 #include <linux/delay.h>
  37 #include <linux/spi/spi.h>
  38 #include <linux/module.h>
  39 #include <linux/iio/iio.h>
  40 #include <linux/regulator/consumer.h>
  41
  42 enum {
  43         mcp3001,
  44         mcp3002,
  45         mcp3004,
  46         mcp3008,
  47         mcp3201,
  48         mcp3202,
  49         mcp3204,
  50         mcp3208,
  51         mcp3301,
  52 };
  53
  54 struct mcp320x_chip_info {
  55         const struct iio_chan_spec *channels;
  56         unsigned int num_channels;
  57         unsigned int resolution;
  58 };
  59
  60 struct mcp320x {
  61         struct spi_device *spi;
  62         struct spi_message msg;
  63         struct spi_transfer transfer[2];
  64
  65         struct regulator *reg;
  66         struct mutex lock;
  67         const struct mcp320x_chip_info *chip_info;
  68
  69         u8 tx_buf ____cacheline_aligned;
  70         u8 rx_buf[2];
  71 };
  72
  73 static int mcp320x_channel_to_tx_data(int device_index,
  74                         const unsigned int channel, bool differential)
  75 {
  76         int start_bit = 1;
  77
  78         switch (device_index) {
  79         case mcp3001:
  80         case mcp3201:
  81         case mcp3301:
  82                 return 0;
  83         case mcp3002:
  84         case mcp3202:
  85                 return ((start_bit << 4) | (!differential << 3) |
  86                                                         (channel << 2));
  87         case mcp3004:
  88         case mcp3204:
  89         case mcp3008:
  90         case mcp3208:
  91                 return ((start_bit << 6) | (!differential << 5) |
  92                                                         (channel << 2));
  93         default:
  94                 return -EINVAL;
  95         }
  96 }
  97
  98 static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
  99                                   bool differential, int device_index)
 100 {
 101         int ret;
 102
 103         adc->rx_buf[0] = 0;
 104         adc->rx_buf[1] = 0;
 105         adc->tx_buf = mcp320x_channel_to_tx_data(device_index,
 106                                                 channel, differential);
 107
 108         if (device_index != mcp3001 && device_index != mcp3201 && device_index != mcp3301) {
 109                 ret = spi_sync(adc->spi, &adc->msg);
 110                 if (ret < 0)
 111                         return ret;
 112         } else {
 113                 ret = spi_read(adc->spi, &adc->rx_buf, sizeof(adc->rx_buf));
 114                 if (ret < 0)
 115                         return ret;
 116         }
 117
 118         switch (device_index) {
 119         case mcp3001:
 120                 return (adc->rx_buf[0] << 5 | adc->rx_buf[1] >> 3);
 121         case mcp3002:
 122         case mcp3004:
 123         case mcp3008:
 124                 return (adc->rx_buf[0] << 2 | adc->rx_buf[1] >> 6);
 125         case mcp3201:
 126                 return (adc->rx_buf[0] << 7 | adc->rx_buf[1] >> 1);
 127         case mcp3202:
 128         case mcp3204:
 129         case mcp3208:
 130                 return (adc->rx_buf[0] << 4 | adc->rx_buf[1] >> 4);
 131         case mcp3301:
 132                 return sign_extend32((adc->rx_buf[0] & 0x1f) << 8 | adc->rx_buf[1], 12);
 133         default:
 134                 return -EINVAL;
 135         }
 136 }
 137
 138 static int mcp320x_read_raw(struct iio_dev *indio_dev,
 139                             struct iio_chan_spec const *channel, int *val,
 140                             int *val2, long mask)
 141 {
 142         struct mcp320x *adc = iio_priv(indio_dev);
 143         int ret = -EINVAL;
 144         int device_index = 0;
 145
 146         mutex_lock(&adc->lock);
 147
 148         device_index = spi_get_device_id(adc->spi)->driver_data;
 149
 150         switch (mask) {
 151         case IIO_CHAN_INFO_RAW:
 152                 ret = mcp320x_adc_conversion(adc, channel->address,
 153                         channel->differential, device_index);
 154
 155                 if (ret < 0)
 156                         goto out;
 157
 158                 *val = ret;
 159                 ret = IIO_VAL_INT;
 160                 break;
 161
 162         case IIO_CHAN_INFO_SCALE:
 163                 ret = regulator_get_voltage(adc->reg);
 164                 if (ret < 0)
 165                         goto out;
 166
 167                 /* convert regulator output voltage to mV */
 168                 *val = ret / 1000;
 169                 *val2 = adc->chip_info->resolution;
 170                 ret = IIO_VAL_FRACTIONAL_LOG2;
 171                 break;
 172         }
 173
 174 out:
 175         mutex_unlock(&adc->lock);
 176
 177         return ret;
 178 }
 179
 180 #define MCP320X_VOLTAGE_CHANNEL(num)                            \
 181         {                                                       \
 182                 .type = IIO_VOLTAGE,                            \
 183                 .indexed = 1,                                   \
 184                 .channel = (num),                               \
 185                 .address = (num),                               \
 186                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 187                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 188         }
 189
 190 #define MCP320X_VOLTAGE_CHANNEL_DIFF(num)                       \
 191         {                                                       \
 192                 .type = IIO_VOLTAGE,                            \
 193                 .indexed = 1,                                   \
 194                 .channel = (num * 2),                           \
 195                 .channel2 = (num * 2 + 1),                      \
 196                 .address = (num * 2),                           \
 197                 .differential = 1,                              \
 198                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 199                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 200         }
 201
 202 static const struct iio_chan_spec mcp3201_channels[] = {
 203         MCP320X_VOLTAGE_CHANNEL_DIFF(0),
 204 };
 205
 206 static const struct iio_chan_spec mcp3202_channels[] = {
 207         MCP320X_VOLTAGE_CHANNEL(0),
 208         MCP320X_VOLTAGE_CHANNEL(1),
 209         MCP320X_VOLTAGE_CHANNEL_DIFF(0),
 210 };
 211
 212 static const struct iio_chan_spec mcp3204_channels[] = {
 213         MCP320X_VOLTAGE_CHANNEL(0),
 214         MCP320X_VOLTAGE_CHANNEL(1),
 215         MCP320X_VOLTAGE_CHANNEL(2),
 216         MCP320X_VOLTAGE_CHANNEL(3),
 217         MCP320X_VOLTAGE_CHANNEL_DIFF(0),
 218         MCP320X_VOLTAGE_CHANNEL_DIFF(1),
 219 };
 220
 221 static const struct iio_chan_spec mcp3208_channels[] = {
 222         MCP320X_VOLTAGE_CHANNEL(0),
 223         MCP320X_VOLTAGE_CHANNEL(1),
 224         MCP320X_VOLTAGE_CHANNEL(2),
 225         MCP320X_VOLTAGE_CHANNEL(3),
 226         MCP320X_VOLTAGE_CHANNEL(4),
 227         MCP320X_VOLTAGE_CHANNEL(5),
 228         MCP320X_VOLTAGE_CHANNEL(6),
 229         MCP320X_VOLTAGE_CHANNEL(7),
 230         MCP320X_VOLTAGE_CHANNEL_DIFF(0),
 231         MCP320X_VOLTAGE_CHANNEL_DIFF(1),
 232         MCP320X_VOLTAGE_CHANNEL_DIFF(2),
 233         MCP320X_VOLTAGE_CHANNEL_DIFF(3),
 234 };
 235
 236 static const struct iio_info mcp320x_info = {
 237         .read_raw = mcp320x_read_raw,
 238         .driver_module = THIS_MODULE,
 239 };
 240
 241 static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
 242         [mcp3001] = {
 243                 .channels = mcp3201_channels,
 244                 .num_channels = ARRAY_SIZE(mcp3201_channels),
 245                 .resolution = 10
 246         },
 247         [mcp3002] = {
 248                 .channels = mcp3202_channels,
 249                 .num_channels = ARRAY_SIZE(mcp3202_channels),
 250                 .resolution = 10
 251         },
 252         [mcp3004] = {
 253                 .channels = mcp3204_channels,
 254                 .num_channels = ARRAY_SIZE(mcp3204_channels),
 255                 .resolution = 10
 256         },
 257         [mcp3008] = {
 258                 .channels = mcp3208_channels,
 259                 .num_channels = ARRAY_SIZE(mcp3208_channels),
 260                 .resolution = 10
 261         },
 262         [mcp3201] = {
 263                 .channels = mcp3201_channels,
 264                 .num_channels = ARRAY_SIZE(mcp3201_channels),
 265                 .resolution = 12
 266         },
 267         [mcp3202] = {
 268                 .channels = mcp3202_channels,
 269                 .num_channels = ARRAY_SIZE(mcp3202_channels),
 270                 .resolution = 12
 271         },
 272         [mcp3204] = {
 273                 .channels = mcp3204_channels,
 274                 .num_channels = ARRAY_SIZE(mcp3204_channels),
 275                 .resolution = 12
 276         },
 277         [mcp3208] = {
 278                 .channels = mcp3208_channels,
 279                 .num_channels = ARRAY_SIZE(mcp3208_channels),
 280                 .resolution = 12
 281         },
 282         [mcp3301] = {
 283                 .channels = mcp3201_channels,
 284                 .num_channels = ARRAY_SIZE(mcp3201_channels),
 285                 .resolution = 13
 286         },
 287 };
 288
 289 static int mcp320x_probe(struct spi_device *spi)
 290 {
 291         struct iio_dev *indio_dev;
 292         struct mcp320x *adc;
 293         const struct mcp320x_chip_info *chip_info;
 294         int ret;
 295
 296         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
 297         if (!indio_dev)
 298                 return -ENOMEM;
 299
 300         adc = iio_priv(indio_dev);
 301         adc->spi = spi;
 302
 303         indio_dev->dev.parent = &spi->dev;
 304         indio_dev->name = spi_get_device_id(spi)->name;
 305         indio_dev->modes = INDIO_DIRECT_MODE;
 306         indio_dev->info = &mcp320x_info;
 307
 308         chip_info = &mcp320x_chip_infos[spi_get_device_id(spi)->driver_data];
 309         indio_dev->channels = chip_info->channels;
 310         indio_dev->num_channels = chip_info->num_channels;
 311
 312         adc->chip_info = chip_info;
 313
 314         adc->transfer[0].tx_buf = &adc->tx_buf;
 315         adc->transfer[0].len = sizeof(adc->tx_buf);
 316         adc->transfer[1].rx_buf = adc->rx_buf;
 317         adc->transfer[1].len = sizeof(adc->rx_buf);
 318
 319         spi_message_init_with_transfers(&adc->msg, adc->transfer,
 320                                         ARRAY_SIZE(adc->transfer));
 321
 322         adc->reg = devm_regulator_get(&spi->dev, "vref");
 323         if (IS_ERR(adc->reg))
 324                 return PTR_ERR(adc->reg);
 325
 326         ret = regulator_enable(adc->reg);
 327         if (ret < 0)
 328                 return ret;
 329
 330         mutex_init(&adc->lock);
 331
 332         ret = iio_device_register(indio_dev);
 333         if (ret < 0)
 334                 goto reg_disable;
 335
 336         return 0;
 337
 338 reg_disable:
 339         regulator_disable(adc->reg);
 340
 341         return ret;
 342 }
 343
 344 static int mcp320x_remove(struct spi_device *spi)
 345 {
 346         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 347         struct mcp320x *adc = iio_priv(indio_dev);
 348
 349         iio_device_unregister(indio_dev);
 350         regulator_disable(adc->reg);
 351
 352         return 0;
 353 }
 354
 355 #if defined(CONFIG_OF)
 356 static const struct of_device_id mcp320x_dt_ids[] = {
 357         {
 358                 .compatible = "mcp3001",
 359                 .data = &mcp320x_chip_infos[mcp3001],
 360         }, {
 361                 .compatible = "mcp3002",
 362                 .data = &mcp320x_chip_infos[mcp3002],
 363         }, {
 364                 .compatible = "mcp3004",
 365                 .data = &mcp320x_chip_infos[mcp3004],
 366         }, {
 367                 .compatible = "mcp3008",
 368                 .data = &mcp320x_chip_infos[mcp3008],
 369         }, {
 370                 .compatible = "mcp3201",
 371                 .data = &mcp320x_chip_infos[mcp3201],
 372         }, {
 373                 .compatible = "mcp3202",
 374                 .data = &mcp320x_chip_infos[mcp3202],
 375         }, {
 376                 .compatible = "mcp3204",
 377                 .data = &mcp320x_chip_infos[mcp3204],
 378         }, {
 379                 .compatible = "mcp3208",
 380                 .data = &mcp320x_chip_infos[mcp3208],
 381         }, {
 382                 .compatible = "mcp3301",
 383                 .data = &mcp320x_chip_infos[mcp3301],
 384         }, {
 385         }
 386 };
 387 MODULE_DEVICE_TABLE(of, mcp320x_dt_ids);
 388 #endif
 389
 390 static const struct spi_device_id mcp320x_id[] = {
 391         { "mcp3001", mcp3001 },
 392         { "mcp3002", mcp3002 },
 393         { "mcp3004", mcp3004 },
 394         { "mcp3008", mcp3008 },
 395         { "mcp3201", mcp3201 },
 396         { "mcp3202", mcp3202 },
 397         { "mcp3204", mcp3204 },
 398         { "mcp3208", mcp3208 },
 399         { "mcp3301", mcp3301 },
 400         { }
 401 };
 402 MODULE_DEVICE_TABLE(spi, mcp320x_id);
 403
 404 static struct spi_driver mcp320x_driver = {
 405         .driver = {
 406                 .name = "mcp320x",
 407                 .of_match_table = of_match_ptr(mcp320x_dt_ids),
 408         },
 409         .probe = mcp320x_probe,
 410         .remove = mcp320x_remove,
 411         .id_table = mcp320x_id,
 412 };
 413 module_spi_driver(mcp320x_driver);
 414
 415 MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
 416 MODULE_DESCRIPTION("Microchip Technology MCP3x01/02/04/08");
 417 MODULE_LICENSE("GPL v2");