drivers/iio/adc/mcp3422.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * mcp3422.c - driver for the Microchip mcp3421/2/3/4/5/6/7/8 chip family
   4  *
   5  * Copyright (C) 2013, Angelo Compagnucci
   6  * Author: Angelo Compagnucci <angelo.compagnucci@gmail.com>
   7  *
   8  * Datasheet: http://ww1.microchip.com/downloads/en/devicedoc/22088b.pdf
   9  *            http://ww1.microchip.com/downloads/en/DeviceDoc/22226a.pdf
  10  *            http://ww1.microchip.com/downloads/en/DeviceDoc/22072b.pdf
  11  *
  12  * This driver exports the value of analog input voltage to sysfs, the
  13  * voltage unit is nV.
  14  */
  15
  16 #include <linux/err.h>
  17 #include <linux/i2c.h>
  18 #include <linux/module.h>
  19 #include <linux/delay.h>
  20 #include <linux/sysfs.h>
  21 #include <linux/of.h>
  22
  23 #include <linux/iio/iio.h>
  24 #include <linux/iio/sysfs.h>
  25
  26 /* Masks */
  27 #define MCP3422_CHANNEL_MASK    0x60
  28 #define MCP3422_PGA_MASK        0x03
  29 #define MCP3422_SRATE_MASK      0x0C
  30 #define MCP3422_SRATE_240       0x0
  31 #define MCP3422_SRATE_60        0x1
  32 #define MCP3422_SRATE_15        0x2
  33 #define MCP3422_SRATE_3 0x3
  34 #define MCP3422_PGA_1   0
  35 #define MCP3422_PGA_2   1
  36 #define MCP3422_PGA_4   2
  37 #define MCP3422_PGA_8   3
  38 #define MCP3422_CONT_SAMPLING   0x10
  39
  40 #define MCP3422_CHANNEL(config) (((config) & MCP3422_CHANNEL_MASK) >> 5)
  41 #define MCP3422_PGA(config)     ((config) & MCP3422_PGA_MASK)
  42 #define MCP3422_SAMPLE_RATE(config)     (((config) & MCP3422_SRATE_MASK) >> 2)
  43
  44 #define MCP3422_CHANNEL_VALUE(value) (((value) << 5) & MCP3422_CHANNEL_MASK)
  45 #define MCP3422_PGA_VALUE(value) ((value) & MCP3422_PGA_MASK)
  46 #define MCP3422_SAMPLE_RATE_VALUE(value) ((value << 2) & MCP3422_SRATE_MASK)
  47
  48 #define MCP3422_CHAN(_index) \
  49         { \
  50                 .type = IIO_VOLTAGE, \
  51                 .indexed = 1, \
  52                 .channel = _index, \
  53                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \
  54                                 | BIT(IIO_CHAN_INFO_SCALE), \
  55                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
  56         }
  57
  58 static const int mcp3422_scales[4][4] = {
  59         { 1000000, 500000, 250000, 125000 },
  60         { 250000,  125000, 62500,  31250  },
  61         { 62500,   31250,  15625,  7812   },
  62         { 15625,   7812,   3906,   1953   } };
  63
  64 /* Constant msleep times for data acquisitions */
  65 static const int mcp3422_read_times[4] = {
  66         [MCP3422_SRATE_240] = 1000 / 240,
  67         [MCP3422_SRATE_60] = 1000 / 60,
  68         [MCP3422_SRATE_15] = 1000 / 15,
  69         [MCP3422_SRATE_3] = 1000 / 3 };
  70
  71 /* sample rates to integer conversion table */
  72 static const int mcp3422_sample_rates[4] = {
  73         [MCP3422_SRATE_240] = 240,
  74         [MCP3422_SRATE_60] = 60,
  75         [MCP3422_SRATE_15] = 15,
  76         [MCP3422_SRATE_3] = 3 };
  77
  78 /* sample rates to sign extension table */
  79 static const int mcp3422_sign_extend[4] = {
  80         [MCP3422_SRATE_240] = 11,
  81         [MCP3422_SRATE_60] = 13,
  82         [MCP3422_SRATE_15] = 15,
  83         [MCP3422_SRATE_3] = 17 };
  84
  85 /* Client data (each client gets its own) */
  86 struct mcp3422 {
  87         struct i2c_client *i2c;
  88         u8 id;
  89         u8 config;
  90         u8 pga[4];
  91         struct mutex lock;
  92 };
  93
  94 static int mcp3422_update_config(struct mcp3422 *adc, u8 newconfig)
  95 {
  96         int ret;
  97
  98         mutex_lock(&adc->lock);
  99
 100         ret = i2c_master_send(adc->i2c, &newconfig, 1);
 101         if (ret > 0) {
 102                 adc->config = newconfig;
 103                 ret = 0;
 104         }
 105
 106         mutex_unlock(&adc->lock);
 107
 108         return ret;
 109 }
 110
 111 static int mcp3422_read(struct mcp3422 *adc, int *value, u8 *config)
 112 {
 113         int ret = 0;
 114         u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
 115         u8 buf[4] = {0, 0, 0, 0};
 116         u32 temp;
 117
 118         if (sample_rate == MCP3422_SRATE_3) {
 119                 ret = i2c_master_recv(adc->i2c, buf, 4);
 120                 temp = buf[0] << 16 | buf[1] << 8 | buf[2];
 121                 *config = buf[3];
 122         } else {
 123                 ret = i2c_master_recv(adc->i2c, buf, 3);
 124                 temp = buf[0] << 8 | buf[1];
 125                 *config = buf[2];
 126         }
 127
 128         *value = sign_extend32(temp, mcp3422_sign_extend[sample_rate]);
 129
 130         return ret;
 131 }
 132
 133 static int mcp3422_read_channel(struct mcp3422 *adc,
 134                                 struct iio_chan_spec const *channel, int *value)
 135 {
 136         int ret;
 137         u8 config;
 138         u8 req_channel = channel->channel;
 139
 140         if (req_channel != MCP3422_CHANNEL(adc->config)) {
 141                 config = adc->config;
 142                 config &= ~MCP3422_CHANNEL_MASK;
 143                 config |= MCP3422_CHANNEL_VALUE(req_channel);
 144                 config &= ~MCP3422_PGA_MASK;
 145                 config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
 146                 ret = mcp3422_update_config(adc, config);
 147                 if (ret < 0)
 148                         return ret;
 149                 msleep(mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->config)]);
 150         }
 151
 152         return mcp3422_read(adc, value, &config);
 153 }
 154
 155 static int mcp3422_read_raw(struct iio_dev *iio,
 156                         struct iio_chan_spec const *channel, int *val1,
 157                         int *val2, long mask)
 158 {
 159         struct mcp3422 *adc = iio_priv(iio);
 160         int err;
 161
 162         u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
 163         u8 pga           = MCP3422_PGA(adc->config);
 164
 165         switch (mask) {
 166         case IIO_CHAN_INFO_RAW:
 167                 err = mcp3422_read_channel(adc, channel, val1);
 168                 if (err < 0)
 169                         return -EINVAL;
 170                 return IIO_VAL_INT;
 171
 172         case IIO_CHAN_INFO_SCALE:
 173
 174                 *val1 = 0;
 175                 *val2 = mcp3422_scales[sample_rate][pga];
 176                 return IIO_VAL_INT_PLUS_NANO;
 177
 178         case IIO_CHAN_INFO_SAMP_FREQ:
 179                 *val1 = mcp3422_sample_rates[MCP3422_SAMPLE_RATE(adc->config)];
 180                 return IIO_VAL_INT;
 181
 182         default:
 183                 break;
 184         }
 185
 186         return -EINVAL;
 187 }
 188
 189 static int mcp3422_write_raw(struct iio_dev *iio,
 190                         struct iio_chan_spec const *channel, int val1,
 191                         int val2, long mask)
 192 {
 193         struct mcp3422 *adc = iio_priv(iio);
 194         u8 temp;
 195         u8 config = adc->config;
 196         u8 req_channel = channel->channel;
 197         u8 sample_rate = MCP3422_SAMPLE_RATE(config);
 198         u8 i;
 199
 200         switch (mask) {
 201         case IIO_CHAN_INFO_SCALE:
 202                 if (val1 != 0)
 203                         return -EINVAL;
 204
 205                 for (i = 0; i < ARRAY_SIZE(mcp3422_scales[0]); i++) {
 206                         if (val2 == mcp3422_scales[sample_rate][i]) {
 207                                 adc->pga[req_channel] = i;
 208
 209                                 config &= ~MCP3422_CHANNEL_MASK;
 210                                 config |= MCP3422_CHANNEL_VALUE(req_channel);
 211                                 config &= ~MCP3422_PGA_MASK;
 212                                 config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
 213
 214                                 return mcp3422_update_config(adc, config);
 215                         }
 216                 }
 217                 return -EINVAL;
 218
 219         case IIO_CHAN_INFO_SAMP_FREQ:
 220                 switch (val1) {
 221                 case 240:
 222                         temp = MCP3422_SRATE_240;
 223                         break;
 224                 case 60:
 225                         temp = MCP3422_SRATE_60;
 226                         break;
 227                 case 15:
 228                         temp = MCP3422_SRATE_15;
 229                         break;
 230                 case 3:
 231                         if (adc->id > 4)
 232                                 return -EINVAL;
 233                         temp = MCP3422_SRATE_3;
 234                         break;
 235                 default:
 236                         return -EINVAL;
 237                 }
 238
 239                 config &= ~MCP3422_CHANNEL_MASK;
 240                 config |= MCP3422_CHANNEL_VALUE(req_channel);
 241                 config &= ~MCP3422_SRATE_MASK;
 242                 config |= MCP3422_SAMPLE_RATE_VALUE(temp);
 243
 244                 return mcp3422_update_config(adc, config);
 245
 246         default:
 247                 break;
 248         }
 249
 250         return -EINVAL;
 251 }
 252
 253 static int mcp3422_write_raw_get_fmt(struct iio_dev *indio_dev,
 254                 struct iio_chan_spec const *chan, long mask)
 255 {
 256         switch (mask) {
 257         case IIO_CHAN_INFO_SCALE:
 258                 return IIO_VAL_INT_PLUS_NANO;
 259         case IIO_CHAN_INFO_SAMP_FREQ:
 260                 return IIO_VAL_INT_PLUS_MICRO;
 261         default:
 262                 return -EINVAL;
 263         }
 264 }
 265
 266 static ssize_t mcp3422_show_samp_freqs(struct device *dev,
 267                 struct device_attribute *attr, char *buf)
 268 {
 269         struct mcp3422 *adc = iio_priv(dev_to_iio_dev(dev));
 270
 271         if (adc->id > 4)
 272                 return sprintf(buf, "240 60 15\n");
 273
 274         return sprintf(buf, "240 60 15 3\n");
 275 }
 276
 277 static ssize_t mcp3422_show_scales(struct device *dev,
 278                 struct device_attribute *attr, char *buf)
 279 {
 280         struct mcp3422 *adc = iio_priv(dev_to_iio_dev(dev));
 281         u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
 282
 283         return sprintf(buf, "0.%09u 0.%09u 0.%09u 0.%09u\n",
 284                 mcp3422_scales[sample_rate][0],
 285                 mcp3422_scales[sample_rate][1],
 286                 mcp3422_scales[sample_rate][2],
 287                 mcp3422_scales[sample_rate][3]);
 288 }
 289
 290 static IIO_DEVICE_ATTR(sampling_frequency_available, S_IRUGO,
 291                 mcp3422_show_samp_freqs, NULL, 0);
 292 static IIO_DEVICE_ATTR(in_voltage_scale_available, S_IRUGO,
 293                 mcp3422_show_scales, NULL, 0);
 294
 295 static struct attribute *mcp3422_attributes[] = {
 296         &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
 297         &iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
 298         NULL,
 299 };
 300
 301 static const struct attribute_group mcp3422_attribute_group = {
 302         .attrs = mcp3422_attributes,
 303 };
 304
 305 static const struct iio_chan_spec mcp3421_channels[] = {
 306         MCP3422_CHAN(0),
 307 };
 308
 309 static const struct iio_chan_spec mcp3422_channels[] = {
 310         MCP3422_CHAN(0),
 311         MCP3422_CHAN(1),
 312 };
 313
 314 static const struct iio_chan_spec mcp3424_channels[] = {
 315         MCP3422_CHAN(0),
 316         MCP3422_CHAN(1),
 317         MCP3422_CHAN(2),
 318         MCP3422_CHAN(3),
 319 };
 320
 321 static const struct iio_info mcp3422_info = {
 322         .read_raw = mcp3422_read_raw,
 323         .write_raw = mcp3422_write_raw,
 324         .write_raw_get_fmt = mcp3422_write_raw_get_fmt,
 325         .attrs = &mcp3422_attribute_group,
 326 };
 327
 328 static int mcp3422_probe(struct i2c_client *client,
 329                          const struct i2c_device_id *id)
 330 {
 331         struct iio_dev *indio_dev;
 332         struct mcp3422 *adc;
 333         int err;
 334         u8 config;
 335
 336         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 337                 return -EOPNOTSUPP;
 338
 339         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*adc));
 340         if (!indio_dev)
 341                 return -ENOMEM;
 342
 343         adc = iio_priv(indio_dev);
 344         adc->i2c = client;
 345         adc->id = (u8)(id->driver_data);
 346
 347         mutex_init(&adc->lock);
 348
 349         indio_dev->dev.parent = &client->dev;
 350         indio_dev->dev.of_node = client->dev.of_node;
 351         indio_dev->name = dev_name(&client->dev);
 352         indio_dev->modes = INDIO_DIRECT_MODE;
 353         indio_dev->info = &mcp3422_info;
 354
 355         switch (adc->id) {
 356         case 1:
 357         case 5:
 358                 indio_dev->channels = mcp3421_channels;
 359                 indio_dev->num_channels = ARRAY_SIZE(mcp3421_channels);
 360                 break;
 361         case 2:
 362         case 3:
 363         case 6:
 364         case 7:
 365                 indio_dev->channels = mcp3422_channels;
 366                 indio_dev->num_channels = ARRAY_SIZE(mcp3422_channels);
 367                 break;
 368         case 4:
 369         case 8:
 370                 indio_dev->channels = mcp3424_channels;
 371                 indio_dev->num_channels = ARRAY_SIZE(mcp3424_channels);
 372                 break;
 373         }
 374
 375         /* meaningful default configuration */
 376         config = (MCP3422_CONT_SAMPLING
 377                 | MCP3422_CHANNEL_VALUE(0)
 378                 | MCP3422_PGA_VALUE(MCP3422_PGA_1)
 379                 | MCP3422_SAMPLE_RATE_VALUE(MCP3422_SRATE_240));
 380         err = mcp3422_update_config(adc, config);
 381         if (err < 0)
 382                 return err;
 383
 384         err = devm_iio_device_register(&client->dev, indio_dev);
 385         if (err < 0)
 386                 return err;
 387
 388         i2c_set_clientdata(client, indio_dev);
 389
 390         return 0;
 391 }
 392
 393 static const struct i2c_device_id mcp3422_id[] = {
 394         { "mcp3421", 1 },
 395         { "mcp3422", 2 },
 396         { "mcp3423", 3 },
 397         { "mcp3424", 4 },
 398         { "mcp3425", 5 },
 399         { "mcp3426", 6 },
 400         { "mcp3427", 7 },
 401         { "mcp3428", 8 },
 402         { }
 403 };
 404 MODULE_DEVICE_TABLE(i2c, mcp3422_id);
 405
 406 #ifdef CONFIG_OF
 407 static const struct of_device_id mcp3422_of_match[] = {
 408         { .compatible = "mcp3422" },
 409         { }
 410 };
 411 MODULE_DEVICE_TABLE(of, mcp3422_of_match);
 412 #endif
 413
 414 static struct i2c_driver mcp3422_driver = {
 415         .driver = {
 416                 .name = "mcp3422",
 417                 .of_match_table = of_match_ptr(mcp3422_of_match),
 418         },
 419         .probe = mcp3422_probe,
 420         .id_table = mcp3422_id,
 421 };
 422 module_i2c_driver(mcp3422_driver);
 423
 424 MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
 425 MODULE_DESCRIPTION("Microchip mcp3421/2/3/4/5/6/7/8 driver");
 426 MODULE_LICENSE("GPL v2");