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