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  *            https://ww1.microchip.com/downloads/en/DeviceDoc/22226a.pdf
  10  *            https://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/mod_devicetable.h>
  20 #include <linux/delay.h>
  21 #include <linux/sysfs.h>
  22 #include <asm/unaligned.h>
  23
  24 #include <linux/iio/iio.h>
  25 #include <linux/iio/sysfs.h>
  26
  27 /* Masks */
  28 #define MCP3422_CHANNEL_MASK    0x60
  29 #define MCP3422_PGA_MASK        0x03
  30 #define MCP3422_SRATE_MASK      0x0C
  31 #define MCP3422_SRATE_240       0x0
  32 #define MCP3422_SRATE_60        0x1
  33 #define MCP3422_SRATE_15        0x2
  34 #define MCP3422_SRATE_3 0x3
  35 #define MCP3422_PGA_1   0
  36 #define MCP3422_PGA_2   1
  37 #define MCP3422_PGA_4   2
  38 #define MCP3422_PGA_8   3
  39 #define MCP3422_CONT_SAMPLING   0x10
  40
  41 #define MCP3422_CHANNEL(config) (((config) & MCP3422_CHANNEL_MASK) >> 5)
  42 #define MCP3422_PGA(config)     ((config) & MCP3422_PGA_MASK)
  43 #define MCP3422_SAMPLE_RATE(config)     (((config) & MCP3422_SRATE_MASK) >> 2)
  44
  45 #define MCP3422_CHANNEL_VALUE(value) (((value) << 5) & MCP3422_CHANNEL_MASK)
  46 #define MCP3422_PGA_VALUE(value) ((value) & MCP3422_PGA_MASK)
  47 #define MCP3422_SAMPLE_RATE_VALUE(value) ((value << 2) & MCP3422_SRATE_MASK)
  48
  49 #define MCP3422_CHAN(_index) \
  50         { \
  51                 .type = IIO_VOLTAGE, \
  52                 .indexed = 1, \
  53                 .channel = _index, \
  54                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \
  55                                 | BIT(IIO_CHAN_INFO_SCALE), \
  56                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
  57         }
  58
  59 static const int mcp3422_scales[4][4] = {
  60         { 1000000, 500000, 250000, 125000 },
  61         { 250000,  125000, 62500,  31250  },
  62         { 62500,   31250,  15625,  7812   },
  63         { 15625,   7812,   3906,   1953   } };
  64
  65 /* Constant msleep times for data acquisitions */
  66 static const int mcp3422_read_times[4] = {
  67         [MCP3422_SRATE_240] = 1000 / 240,
  68         [MCP3422_SRATE_60] = 1000 / 60,
  69         [MCP3422_SRATE_15] = 1000 / 15,
  70         [MCP3422_SRATE_3] = 1000 / 3 };
  71
  72 /* sample rates to integer conversion table */
  73 static const int mcp3422_sample_rates[4] = {
  74         [MCP3422_SRATE_240] = 240,
  75         [MCP3422_SRATE_60] = 60,
  76         [MCP3422_SRATE_15] = 15,
  77         [MCP3422_SRATE_3] = 3 };
  78
  79 /* sample rates to sign extension table */
  80 static const int mcp3422_sign_extend[4] = {
  81         [MCP3422_SRATE_240] = 11,
  82         [MCP3422_SRATE_60] = 13,
  83         [MCP3422_SRATE_15] = 15,
  84         [MCP3422_SRATE_3] = 17 };
  85
  86 /* Client data (each client gets its own) */
  87 struct mcp3422 {
  88         struct i2c_client *i2c;
  89         u8 id;
  90         u8 config;
  91         u8 pga[4];
  92         struct mutex lock;
  93 };
  94
  95 static int mcp3422_update_config(struct mcp3422 *adc, u8 newconfig)
  96 {
  97         int ret;
  98
  99         ret = i2c_master_send(adc->i2c, &newconfig, 1);
 100         if (ret > 0) {
 101                 adc->config = newconfig;
 102                 ret = 0;
 103         }
 104
 105         return ret;
 106 }
 107
 108 static int mcp3422_read(struct mcp3422 *adc, int *value, u8 *config)
 109 {
 110         int ret = 0;
 111         u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
 112         u8 buf[4] = {0, 0, 0, 0};
 113         u32 temp;
 114
 115         if (sample_rate == MCP3422_SRATE_3) {
 116                 ret = i2c_master_recv(adc->i2c, buf, 4);
 117                 temp = get_unaligned_be24(&buf[0]);
 118                 *config = buf[3];
 119         } else {
 120                 ret = i2c_master_recv(adc->i2c, buf, 3);
 121                 temp = get_unaligned_be16(&buf[0]);
 122                 *config = buf[2];
 123         }
 124
 125         *value = sign_extend32(temp, mcp3422_sign_extend[sample_rate]);
 126
 127         return ret;
 128 }
 129
 130 static int mcp3422_read_channel(struct mcp3422 *adc,
 131                                 struct iio_chan_spec const *channel, int *value)
 132 {
 133         int ret;
 134         u8 config;
 135         u8 req_channel = channel->channel;
 136
 137         mutex_lock(&adc->lock);
 138
 139         if (req_channel != MCP3422_CHANNEL(adc->config)) {
 140                 config = adc->config;
 141                 config &= ~MCP3422_CHANNEL_MASK;
 142                 config |= MCP3422_CHANNEL_VALUE(req_channel);
 143                 config &= ~MCP3422_PGA_MASK;
 144                 config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
 145                 ret = mcp3422_update_config(adc, config);
 146                 if (ret < 0) {
 147                         mutex_unlock(&adc->lock);
 148                         return ret;
 149                 }
 150                 msleep(mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->config)]);
 151         }
 152
 153         ret = mcp3422_read(adc, value, &config);
 154
 155         mutex_unlock(&adc->lock);
 156
 157         return ret;
 158 }
 159
 160 static int mcp3422_read_raw(struct iio_dev *iio,
 161                         struct iio_chan_spec const *channel, int *val1,
 162                         int *val2, long mask)
 163 {
 164         struct mcp3422 *adc = iio_priv(iio);
 165         int err;
 166
 167         u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
 168         u8 pga           = MCP3422_PGA(adc->config);
 169
 170         switch (mask) {
 171         case IIO_CHAN_INFO_RAW:
 172                 err = mcp3422_read_channel(adc, channel, val1);
 173                 if (err < 0)
 174                         return -EINVAL;
 175                 return IIO_VAL_INT;
 176
 177         case IIO_CHAN_INFO_SCALE:
 178
 179                 *val1 = 0;
 180                 *val2 = mcp3422_scales[sample_rate][pga];
 181                 return IIO_VAL_INT_PLUS_NANO;
 182
 183         case IIO_CHAN_INFO_SAMP_FREQ:
 184                 *val1 = mcp3422_sample_rates[MCP3422_SAMPLE_RATE(adc->config)];
 185                 return IIO_VAL_INT;
 186
 187         default:
 188                 break;
 189         }
 190
 191         return -EINVAL;
 192 }
 193
 194 static int mcp3422_write_raw(struct iio_dev *iio,
 195                         struct iio_chan_spec const *channel, int val1,
 196                         int val2, long mask)
 197 {
 198         struct mcp3422 *adc = iio_priv(iio);
 199         u8 temp;
 200         u8 config = adc->config;
 201         u8 req_channel = channel->channel;
 202         u8 sample_rate = MCP3422_SAMPLE_RATE(config);
 203         u8 i;
 204
 205         switch (mask) {
 206         case IIO_CHAN_INFO_SCALE:
 207                 if (val1 != 0)
 208                         return -EINVAL;
 209
 210                 for (i = 0; i < ARRAY_SIZE(mcp3422_scales[0]); i++) {
 211                         if (val2 == mcp3422_scales[sample_rate][i]) {
 212                                 adc->pga[req_channel] = i;
 213
 214                                 config &= ~MCP3422_CHANNEL_MASK;
 215                                 config |= MCP3422_CHANNEL_VALUE(req_channel);
 216                                 config &= ~MCP3422_PGA_MASK;
 217                                 config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
 218
 219                                 return mcp3422_update_config(adc, config);
 220                         }
 221                 }
 222                 return -EINVAL;
 223
 224         case IIO_CHAN_INFO_SAMP_FREQ:
 225                 switch (val1) {
 226                 case 240:
 227                         temp = MCP3422_SRATE_240;
 228                         break;
 229                 case 60:
 230                         temp = MCP3422_SRATE_60;
 231                         break;
 232                 case 15:
 233                         temp = MCP3422_SRATE_15;
 234                         break;
 235                 case 3:
 236                         if (adc->id > 4)
 237                                 return -EINVAL;
 238                         temp = MCP3422_SRATE_3;
 239                         break;
 240                 default:
 241                         return -EINVAL;
 242                 }
 243
 244                 config &= ~MCP3422_CHANNEL_MASK;
 245                 config |= MCP3422_CHANNEL_VALUE(req_channel);
 246                 config &= ~MCP3422_SRATE_MASK;
 247                 config |= MCP3422_SAMPLE_RATE_VALUE(temp);
 248
 249                 return mcp3422_update_config(adc, config);
 250
 251         default:
 252                 break;
 253         }
 254
 255         return -EINVAL;
 256 }
 257
 258 static int mcp3422_write_raw_get_fmt(struct iio_dev *indio_dev,
 259                 struct iio_chan_spec const *chan, long mask)
 260 {
 261         switch (mask) {
 262         case IIO_CHAN_INFO_SCALE:
 263                 return IIO_VAL_INT_PLUS_NANO;
 264         case IIO_CHAN_INFO_SAMP_FREQ:
 265                 return IIO_VAL_INT_PLUS_MICRO;
 266         default:
 267                 return -EINVAL;
 268         }
 269 }
 270
 271 static ssize_t mcp3422_show_samp_freqs(struct device *dev,
 272                 struct device_attribute *attr, char *buf)
 273 {
 274         struct mcp3422 *adc = iio_priv(dev_to_iio_dev(dev));
 275
 276         if (adc->id > 4)
 277                 return sprintf(buf, "240 60 15\n");
 278
 279         return sprintf(buf, "240 60 15 3\n");
 280 }
 281
 282 static ssize_t mcp3422_show_scales(struct device *dev,
 283                 struct device_attribute *attr, char *buf)
 284 {
 285         struct mcp3422 *adc = iio_priv(dev_to_iio_dev(dev));
 286         u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
 287
 288         return sprintf(buf, "0.%09u 0.%09u 0.%09u 0.%09u\n",
 289                 mcp3422_scales[sample_rate][0],
 290                 mcp3422_scales[sample_rate][1],
 291                 mcp3422_scales[sample_rate][2],
 292                 mcp3422_scales[sample_rate][3]);
 293 }
 294
 295 static IIO_DEVICE_ATTR(sampling_frequency_available, S_IRUGO,
 296                 mcp3422_show_samp_freqs, NULL, 0);
 297 static IIO_DEVICE_ATTR(in_voltage_scale_available, S_IRUGO,
 298                 mcp3422_show_scales, NULL, 0);
 299
 300 static struct attribute *mcp3422_attributes[] = {
 301         &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
 302         &iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
 303         NULL,
 304 };
 305
 306 static const struct attribute_group mcp3422_attribute_group = {
 307         .attrs = mcp3422_attributes,
 308 };
 309
 310 static const struct iio_chan_spec mcp3421_channels[] = {
 311         MCP3422_CHAN(0),
 312 };
 313
 314 static const struct iio_chan_spec mcp3422_channels[] = {
 315         MCP3422_CHAN(0),
 316         MCP3422_CHAN(1),
 317 };
 318
 319 static const struct iio_chan_spec mcp3424_channels[] = {
 320         MCP3422_CHAN(0),
 321         MCP3422_CHAN(1),
 322         MCP3422_CHAN(2),
 323         MCP3422_CHAN(3),
 324 };
 325
 326 static const struct iio_info mcp3422_info = {
 327         .read_raw = mcp3422_read_raw,
 328         .write_raw = mcp3422_write_raw,
 329         .write_raw_get_fmt = mcp3422_write_raw_get_fmt,
 330         .attrs = &mcp3422_attribute_group,
 331 };
 332
 333 static int mcp3422_probe(struct i2c_client *client,
 334                          const struct i2c_device_id *id)
 335 {
 336         struct iio_dev *indio_dev;
 337         struct mcp3422 *adc;
 338         int err;
 339         u8 config;
 340
 341         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 342                 return -EOPNOTSUPP;
 343
 344         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*adc));
 345         if (!indio_dev)
 346                 return -ENOMEM;
 347
 348         adc = iio_priv(indio_dev);
 349         adc->i2c = client;
 350         adc->id = (u8)(id->driver_data);
 351
 352         mutex_init(&adc->lock);
 353
 354         indio_dev->name = dev_name(&client->dev);
 355         indio_dev->modes = INDIO_DIRECT_MODE;
 356         indio_dev->info = &mcp3422_info;
 357
 358         switch (adc->id) {
 359         case 1:
 360         case 5:
 361                 indio_dev->channels = mcp3421_channels;
 362                 indio_dev->num_channels = ARRAY_SIZE(mcp3421_channels);
 363                 break;
 364         case 2:
 365         case 3:
 366         case 6:
 367         case 7:
 368                 indio_dev->channels = mcp3422_channels;
 369                 indio_dev->num_channels = ARRAY_SIZE(mcp3422_channels);
 370                 break;
 371         case 4:
 372         case 8:
 373                 indio_dev->channels = mcp3424_channels;
 374                 indio_dev->num_channels = ARRAY_SIZE(mcp3424_channels);
 375                 break;
 376         }
 377
 378         /* meaningful default configuration */
 379         config = (MCP3422_CONT_SAMPLING
 380                 | MCP3422_CHANNEL_VALUE(0)
 381                 | MCP3422_PGA_VALUE(MCP3422_PGA_1)
 382                 | MCP3422_SAMPLE_RATE_VALUE(MCP3422_SRATE_240));
 383         err = mcp3422_update_config(adc, config);
 384         if (err < 0)
 385                 return err;
 386
 387         err = devm_iio_device_register(&client->dev, indio_dev);
 388         if (err < 0)
 389                 return err;
 390
 391         i2c_set_clientdata(client, indio_dev);
 392
 393         return 0;
 394 }
 395
 396 static const struct i2c_device_id mcp3422_id[] = {
 397         { "mcp3421", 1 },
 398         { "mcp3422", 2 },
 399         { "mcp3423", 3 },
 400         { "mcp3424", 4 },
 401         { "mcp3425", 5 },
 402         { "mcp3426", 6 },
 403         { "mcp3427", 7 },
 404         { "mcp3428", 8 },
 405         { }
 406 };
 407 MODULE_DEVICE_TABLE(i2c, mcp3422_id);
 408
 409 static const struct of_device_id mcp3422_of_match[] = {
 410         { .compatible = "mcp3422" },
 411         { }
 412 };
 413 MODULE_DEVICE_TABLE(of, mcp3422_of_match);
 414
 415 static struct i2c_driver mcp3422_driver = {
 416         .driver = {
 417                 .name = "mcp3422",
 418                 .of_match_table = mcp3422_of_match,
 419         },
 420         .probe = mcp3422_probe,
 421         .id_table = mcp3422_id,
 422 };
 423 module_i2c_driver(mcp3422_driver);
 424
 425 MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
 426 MODULE_DESCRIPTION("Microchip mcp3421/2/3/4/5/6/7/8 driver");
 427 MODULE_LICENSE("GPL v2");