drivers/iio/potentiometer/mcp4531.c

   1 /*
   2  * Industrial I/O driver for Microchip digital potentiometers
   3  * Copyright (c) 2015  Axentia Technologies AB
   4  * Author: Peter Rosin <peda@axentia.se>
   5  *
   6  * Datasheet: http://www.microchip.com/downloads/en/DeviceDoc/22096b.pdf
   7  *
   8  * DEVID        #Wipers #Positions      Resistor Opts (kOhm)    i2c address
   9  * mcp4531      1       129             5, 10, 50, 100          010111x
  10  * mcp4532      1       129             5, 10, 50, 100          01011xx
  11  * mcp4541      1       129             5, 10, 50, 100          010111x
  12  * mcp4542      1       129             5, 10, 50, 100          01011xx
  13  * mcp4551      1       257             5, 10, 50, 100          010111x
  14  * mcp4552      1       257             5, 10, 50, 100          01011xx
  15  * mcp4561      1       257             5, 10, 50, 100          010111x
  16  * mcp4562      1       257             5, 10, 50, 100          01011xx
  17  * mcp4631      2       129             5, 10, 50, 100          0101xxx
  18  * mcp4632      2       129             5, 10, 50, 100          01011xx
  19  * mcp4641      2       129             5, 10, 50, 100          0101xxx
  20  * mcp4642      2       129             5, 10, 50, 100          01011xx
  21  * mcp4651      2       257             5, 10, 50, 100          0101xxx
  22  * mcp4652      2       257             5, 10, 50, 100          01011xx
  23  * mcp4661      2       257             5, 10, 50, 100          0101xxx
  24  * mcp4662      2       257             5, 10, 50, 100          01011xx
  25  *
  26  * This program is free software; you can redistribute it and/or modify it
  27  * under the terms of the GNU General Public License version 2 as published by
  28  * the Free Software Foundation.
  29  */
  30
  31 #include <linux/module.h>
  32 #include <linux/i2c.h>
  33 #include <linux/err.h>
  34 #include <linux/of.h>
  35 #include <linux/of_device.h>
  36
  37 #include <linux/iio/iio.h>
  38
  39 struct mcp4531_cfg {
  40         int wipers;
  41         int avail[3];
  42         int kohms;
  43 };
  44
  45 enum mcp4531_type {
  46         MCP453x_502,
  47         MCP453x_103,
  48         MCP453x_503,
  49         MCP453x_104,
  50         MCP454x_502,
  51         MCP454x_103,
  52         MCP454x_503,
  53         MCP454x_104,
  54         MCP455x_502,
  55         MCP455x_103,
  56         MCP455x_503,
  57         MCP455x_104,
  58         MCP456x_502,
  59         MCP456x_103,
  60         MCP456x_503,
  61         MCP456x_104,
  62         MCP463x_502,
  63         MCP463x_103,
  64         MCP463x_503,
  65         MCP463x_104,
  66         MCP464x_502,
  67         MCP464x_103,
  68         MCP464x_503,
  69         MCP464x_104,
  70         MCP465x_502,
  71         MCP465x_103,
  72         MCP465x_503,
  73         MCP465x_104,
  74         MCP466x_502,
  75         MCP466x_103,
  76         MCP466x_503,
  77         MCP466x_104,
  78 };
  79
  80 static const struct mcp4531_cfg mcp4531_cfg[] = {
  81         [MCP453x_502] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms =   5, },
  82         [MCP453x_103] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms =  10, },
  83         [MCP453x_503] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms =  50, },
  84         [MCP453x_104] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms = 100, },
  85         [MCP454x_502] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms =   5, },
  86         [MCP454x_103] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms =  10, },
  87         [MCP454x_503] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms =  50, },
  88         [MCP454x_104] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms = 100, },
  89         [MCP455x_502] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms =   5, },
  90         [MCP455x_103] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms =  10, },
  91         [MCP455x_503] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms =  50, },
  92         [MCP455x_104] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms = 100, },
  93         [MCP456x_502] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms =   5, },
  94         [MCP456x_103] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms =  10, },
  95         [MCP456x_503] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms =  50, },
  96         [MCP456x_104] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms = 100, },
  97         [MCP463x_502] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms =   5, },
  98         [MCP463x_103] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms =  10, },
  99         [MCP463x_503] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms =  50, },
 100         [MCP463x_104] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms = 100, },
 101         [MCP464x_502] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms =   5, },
 102         [MCP464x_103] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms =  10, },
 103         [MCP464x_503] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms =  50, },
 104         [MCP464x_104] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms = 100, },
 105         [MCP465x_502] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms =   5, },
 106         [MCP465x_103] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms =  10, },
 107         [MCP465x_503] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms =  50, },
 108         [MCP465x_104] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms = 100, },
 109         [MCP466x_502] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms =   5, },
 110         [MCP466x_103] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms =  10, },
 111         [MCP466x_503] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms =  50, },
 112         [MCP466x_104] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms = 100, },
 113 };
 114
 115 #define MCP4531_WRITE (0 << 2)
 116 #define MCP4531_INCR  (1 << 2)
 117 #define MCP4531_DECR  (2 << 2)
 118 #define MCP4531_READ  (3 << 2)
 119
 120 #define MCP4531_WIPER_SHIFT (4)
 121
 122 struct mcp4531_data {
 123         struct i2c_client *client;
 124         const struct mcp4531_cfg *cfg;
 125 };
 126
 127 #define MCP4531_CHANNEL(ch) {                                           \
 128         .type = IIO_RESISTANCE,                                         \
 129         .indexed = 1,                                                   \
 130         .output = 1,                                                    \
 131         .channel = (ch),                                                \
 132         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),                   \
 133         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),           \
 134         .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_RAW),   \
 135 }
 136
 137 static const struct iio_chan_spec mcp4531_channels[] = {
 138         MCP4531_CHANNEL(0),
 139         MCP4531_CHANNEL(1),
 140 };
 141
 142 static int mcp4531_read_raw(struct iio_dev *indio_dev,
 143                             struct iio_chan_spec const *chan,
 144                             int *val, int *val2, long mask)
 145 {
 146         struct mcp4531_data *data = iio_priv(indio_dev);
 147         int address = chan->channel << MCP4531_WIPER_SHIFT;
 148         s32 ret;
 149
 150         switch (mask) {
 151         case IIO_CHAN_INFO_RAW:
 152                 ret = i2c_smbus_read_word_swapped(data->client,
 153                                                   MCP4531_READ | address);
 154                 if (ret < 0)
 155                         return ret;
 156                 *val = ret;
 157                 return IIO_VAL_INT;
 158         case IIO_CHAN_INFO_SCALE:
 159                 *val = 1000 * data->cfg->kohms;
 160                 *val2 = data->cfg->avail[2];
 161                 return IIO_VAL_FRACTIONAL;
 162         }
 163
 164         return -EINVAL;
 165 }
 166
 167 static int mcp4531_read_avail(struct iio_dev *indio_dev,
 168                               struct iio_chan_spec const *chan,
 169                               const int **vals, int *type, int *length,
 170                               long mask)
 171 {
 172         struct mcp4531_data *data = iio_priv(indio_dev);
 173
 174         switch (mask) {
 175         case IIO_CHAN_INFO_RAW:
 176                 *length = ARRAY_SIZE(data->cfg->avail);
 177                 *vals = data->cfg->avail;
 178                 *type = IIO_VAL_INT;
 179                 return IIO_AVAIL_RANGE;
 180         }
 181
 182         return -EINVAL;
 183 }
 184
 185 static int mcp4531_write_raw(struct iio_dev *indio_dev,
 186                              struct iio_chan_spec const *chan,
 187                              int val, int val2, long mask)
 188 {
 189         struct mcp4531_data *data = iio_priv(indio_dev);
 190         int address = chan->channel << MCP4531_WIPER_SHIFT;
 191
 192         switch (mask) {
 193         case IIO_CHAN_INFO_RAW:
 194                 if (val > data->cfg->avail[2] || val < 0)
 195                         return -EINVAL;
 196                 break;
 197         default:
 198                 return -EINVAL;
 199         }
 200
 201         return i2c_smbus_write_byte_data(data->client,
 202                                          MCP4531_WRITE | address | (val >> 8),
 203                                          val & 0xff);
 204 }
 205
 206 static const struct iio_info mcp4531_info = {
 207         .read_raw = mcp4531_read_raw,
 208         .read_avail = mcp4531_read_avail,
 209         .write_raw = mcp4531_write_raw,
 210 };
 211
 212 static const struct i2c_device_id mcp4531_id[] = {
 213         { "mcp4531-502", MCP453x_502 },
 214         { "mcp4531-103", MCP453x_103 },
 215         { "mcp4531-503", MCP453x_503 },
 216         { "mcp4531-104", MCP453x_104 },
 217         { "mcp4532-502", MCP453x_502 },
 218         { "mcp4532-103", MCP453x_103 },
 219         { "mcp4532-503", MCP453x_503 },
 220         { "mcp4532-104", MCP453x_104 },
 221         { "mcp4541-502", MCP454x_502 },
 222         { "mcp4541-103", MCP454x_103 },
 223         { "mcp4541-503", MCP454x_503 },
 224         { "mcp4541-104", MCP454x_104 },
 225         { "mcp4542-502", MCP454x_502 },
 226         { "mcp4542-103", MCP454x_103 },
 227         { "mcp4542-503", MCP454x_503 },
 228         { "mcp4542-104", MCP454x_104 },
 229         { "mcp4551-502", MCP455x_502 },
 230         { "mcp4551-103", MCP455x_103 },
 231         { "mcp4551-503", MCP455x_503 },
 232         { "mcp4551-104", MCP455x_104 },
 233         { "mcp4552-502", MCP455x_502 },
 234         { "mcp4552-103", MCP455x_103 },
 235         { "mcp4552-503", MCP455x_503 },
 236         { "mcp4552-104", MCP455x_104 },
 237         { "mcp4561-502", MCP456x_502 },
 238         { "mcp4561-103", MCP456x_103 },
 239         { "mcp4561-503", MCP456x_503 },
 240         { "mcp4561-104", MCP456x_104 },
 241         { "mcp4562-502", MCP456x_502 },
 242         { "mcp4562-103", MCP456x_103 },
 243         { "mcp4562-503", MCP456x_503 },
 244         { "mcp4562-104", MCP456x_104 },
 245         { "mcp4631-502", MCP463x_502 },
 246         { "mcp4631-103", MCP463x_103 },
 247         { "mcp4631-503", MCP463x_503 },
 248         { "mcp4631-104", MCP463x_104 },
 249         { "mcp4632-502", MCP463x_502 },
 250         { "mcp4632-103", MCP463x_103 },
 251         { "mcp4632-503", MCP463x_503 },
 252         { "mcp4632-104", MCP463x_104 },
 253         { "mcp4641-502", MCP464x_502 },
 254         { "mcp4641-103", MCP464x_103 },
 255         { "mcp4641-503", MCP464x_503 },
 256         { "mcp4641-104", MCP464x_104 },
 257         { "mcp4642-502", MCP464x_502 },
 258         { "mcp4642-103", MCP464x_103 },
 259         { "mcp4642-503", MCP464x_503 },
 260         { "mcp4642-104", MCP464x_104 },
 261         { "mcp4651-502", MCP465x_502 },
 262         { "mcp4651-103", MCP465x_103 },
 263         { "mcp4651-503", MCP465x_503 },
 264         { "mcp4651-104", MCP465x_104 },
 265         { "mcp4652-502", MCP465x_502 },
 266         { "mcp4652-103", MCP465x_103 },
 267         { "mcp4652-503", MCP465x_503 },
 268         { "mcp4652-104", MCP465x_104 },
 269         { "mcp4661-502", MCP466x_502 },
 270         { "mcp4661-103", MCP466x_103 },
 271         { "mcp4661-503", MCP466x_503 },
 272         { "mcp4661-104", MCP466x_104 },
 273         { "mcp4662-502", MCP466x_502 },
 274         { "mcp4662-103", MCP466x_103 },
 275         { "mcp4662-503", MCP466x_503 },
 276         { "mcp4662-104", MCP466x_104 },
 277         {}
 278 };
 279 MODULE_DEVICE_TABLE(i2c, mcp4531_id);
 280
 281 #ifdef CONFIG_OF
 282
 283 #define MCP4531_COMPATIBLE(of_compatible, cfg) {        \
 284                         .compatible = of_compatible,    \
 285                         .data = &mcp4531_cfg[cfg],      \
 286 }
 287
 288 static const struct of_device_id mcp4531_of_match[] = {
 289         MCP4531_COMPATIBLE("microchip,mcp4531-502", MCP453x_502),
 290         MCP4531_COMPATIBLE("microchip,mcp4531-103", MCP453x_103),
 291         MCP4531_COMPATIBLE("microchip,mcp4531-503", MCP453x_503),
 292         MCP4531_COMPATIBLE("microchip,mcp4531-104", MCP453x_104),
 293         MCP4531_COMPATIBLE("microchip,mcp4532-502", MCP453x_502),
 294         MCP4531_COMPATIBLE("microchip,mcp4532-103", MCP453x_103),
 295         MCP4531_COMPATIBLE("microchip,mcp4532-503", MCP453x_503),
 296         MCP4531_COMPATIBLE("microchip,mcp4532-104", MCP453x_104),
 297         MCP4531_COMPATIBLE("microchip,mcp4541-502", MCP454x_502),
 298         MCP4531_COMPATIBLE("microchip,mcp4541-103", MCP454x_103),
 299         MCP4531_COMPATIBLE("microchip,mcp4541-503", MCP454x_503),
 300         MCP4531_COMPATIBLE("microchip,mcp4541-104", MCP454x_104),
 301         MCP4531_COMPATIBLE("microchip,mcp4542-502", MCP454x_502),
 302         MCP4531_COMPATIBLE("microchip,mcp4542-103", MCP454x_103),
 303         MCP4531_COMPATIBLE("microchip,mcp4542-503", MCP454x_503),
 304         MCP4531_COMPATIBLE("microchip,mcp4542-104", MCP454x_104),
 305         MCP4531_COMPATIBLE("microchip,mcp4551-502", MCP455x_502),
 306         MCP4531_COMPATIBLE("microchip,mcp4551-103", MCP455x_103),
 307         MCP4531_COMPATIBLE("microchip,mcp4551-503", MCP455x_503),
 308         MCP4531_COMPATIBLE("microchip,mcp4551-104", MCP455x_104),
 309         MCP4531_COMPATIBLE("microchip,mcp4552-502", MCP455x_502),
 310         MCP4531_COMPATIBLE("microchip,mcp4552-103", MCP455x_103),
 311         MCP4531_COMPATIBLE("microchip,mcp4552-503", MCP455x_503),
 312         MCP4531_COMPATIBLE("microchip,mcp4552-104", MCP455x_104),
 313         MCP4531_COMPATIBLE("microchip,mcp4561-502", MCP456x_502),
 314         MCP4531_COMPATIBLE("microchip,mcp4561-103", MCP456x_103),
 315         MCP4531_COMPATIBLE("microchip,mcp4561-503", MCP456x_503),
 316         MCP4531_COMPATIBLE("microchip,mcp4561-104", MCP456x_104),
 317         MCP4531_COMPATIBLE("microchip,mcp4562-502", MCP456x_502),
 318         MCP4531_COMPATIBLE("microchip,mcp4562-103", MCP456x_103),
 319         MCP4531_COMPATIBLE("microchip,mcp4562-503", MCP456x_503),
 320         MCP4531_COMPATIBLE("microchip,mcp4562-104", MCP456x_104),
 321         MCP4531_COMPATIBLE("microchip,mcp4631-502", MCP463x_502),
 322         MCP4531_COMPATIBLE("microchip,mcp4631-103", MCP463x_103),
 323         MCP4531_COMPATIBLE("microchip,mcp4631-503", MCP463x_503),
 324         MCP4531_COMPATIBLE("microchip,mcp4631-104", MCP463x_104),
 325         MCP4531_COMPATIBLE("microchip,mcp4632-502", MCP463x_502),
 326         MCP4531_COMPATIBLE("microchip,mcp4632-103", MCP463x_103),
 327         MCP4531_COMPATIBLE("microchip,mcp4632-503", MCP463x_503),
 328         MCP4531_COMPATIBLE("microchip,mcp4632-104", MCP463x_104),
 329         MCP4531_COMPATIBLE("microchip,mcp4641-502", MCP464x_502),
 330         MCP4531_COMPATIBLE("microchip,mcp4641-103", MCP464x_103),
 331         MCP4531_COMPATIBLE("microchip,mcp4641-503", MCP464x_503),
 332         MCP4531_COMPATIBLE("microchip,mcp4641-104", MCP464x_104),
 333         MCP4531_COMPATIBLE("microchip,mcp4642-502", MCP464x_502),
 334         MCP4531_COMPATIBLE("microchip,mcp4642-103", MCP464x_103),
 335         MCP4531_COMPATIBLE("microchip,mcp4642-503", MCP464x_503),
 336         MCP4531_COMPATIBLE("microchip,mcp4642-104", MCP464x_104),
 337         MCP4531_COMPATIBLE("microchip,mcp4651-502", MCP465x_502),
 338         MCP4531_COMPATIBLE("microchip,mcp4651-103", MCP465x_103),
 339         MCP4531_COMPATIBLE("microchip,mcp4651-503", MCP465x_503),
 340         MCP4531_COMPATIBLE("microchip,mcp4651-104", MCP465x_104),
 341         MCP4531_COMPATIBLE("microchip,mcp4652-502", MCP465x_502),
 342         MCP4531_COMPATIBLE("microchip,mcp4652-103", MCP465x_103),
 343         MCP4531_COMPATIBLE("microchip,mcp4652-503", MCP465x_503),
 344         MCP4531_COMPATIBLE("microchip,mcp4652-104", MCP465x_104),
 345         MCP4531_COMPATIBLE("microchip,mcp4661-502", MCP466x_502),
 346         MCP4531_COMPATIBLE("microchip,mcp4661-103", MCP466x_103),
 347         MCP4531_COMPATIBLE("microchip,mcp4661-503", MCP466x_503),
 348         MCP4531_COMPATIBLE("microchip,mcp4661-104", MCP466x_104),
 349         MCP4531_COMPATIBLE("microchip,mcp4662-502", MCP466x_502),
 350         MCP4531_COMPATIBLE("microchip,mcp4662-103", MCP466x_103),
 351         MCP4531_COMPATIBLE("microchip,mcp4662-503", MCP466x_503),
 352         MCP4531_COMPATIBLE("microchip,mcp4662-104", MCP466x_104),
 353         { /* sentinel */ }
 354 };
 355 MODULE_DEVICE_TABLE(of, mcp4531_of_match);
 356 #endif
 357
 358 static int mcp4531_probe(struct i2c_client *client)
 359 {
 360         struct device *dev = &client->dev;
 361         struct mcp4531_data *data;
 362         struct iio_dev *indio_dev;
 363         const struct of_device_id *match;
 364
 365         if (!i2c_check_functionality(client->adapter,
 366                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 367                 dev_err(dev, "SMBUS Word Data not supported\n");
 368                 return -EOPNOTSUPP;
 369         }
 370
 371         indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 372         if (!indio_dev)
 373                 return -ENOMEM;
 374         data = iio_priv(indio_dev);
 375         i2c_set_clientdata(client, indio_dev);
 376         data->client = client;
 377
 378         match = of_match_device(of_match_ptr(mcp4531_of_match), dev);
 379         if (match)
 380                 data->cfg = of_device_get_match_data(dev);
 381         else
 382                 data->cfg = &mcp4531_cfg[i2c_match_id(mcp4531_id, client)->driver_data];
 383
 384         indio_dev->dev.parent = dev;
 385         indio_dev->info = &mcp4531_info;
 386         indio_dev->channels = mcp4531_channels;
 387         indio_dev->num_channels = data->cfg->wipers;
 388         indio_dev->name = client->name;
 389
 390         return devm_iio_device_register(dev, indio_dev);
 391 }
 392
 393 static struct i2c_driver mcp4531_driver = {
 394         .driver = {
 395                 .name   = "mcp4531",
 396                 .of_match_table = of_match_ptr(mcp4531_of_match),
 397         },
 398         .probe_new      = mcp4531_probe,
 399         .id_table       = mcp4531_id,
 400 };
 401
 402 module_i2c_driver(mcp4531_driver);
 403
 404 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
 405 MODULE_DESCRIPTION("MCP4531 digital potentiometer");
 406 MODULE_LICENSE("GPL");