drivers/iio/dac/mcp4725.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * mcp4725.c - Support for Microchip MCP4725/6
   4  *
   5  * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
   6  *
   7  * Based on max517 by Roland Stigge <stigge@antcom.de>
   8  *
   9  * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
  10  * (7-bit I2C slave address 0x60, the three LSBs can be configured in
  11  * hardware)
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/i2c.h>
  16 #include <linux/err.h>
  17 #include <linux/delay.h>
  18 #include <linux/regulator/consumer.h>
  19 #include <linux/mod_devicetable.h>
  20 #include <linux/property.h>
  21
  22 #include <linux/iio/iio.h>
  23 #include <linux/iio/sysfs.h>
  24
  25 #include <linux/iio/dac/mcp4725.h>
  26
  27 #define MCP4725_DRV_NAME "mcp4725"
  28
  29 #define MCP472X_REF_VDD                 0x00
  30 #define MCP472X_REF_VREF_UNBUFFERED     0x02
  31 #define MCP472X_REF_VREF_BUFFERED       0x03
  32
  33 struct mcp4725_chip_info {
  34         const struct iio_chan_spec *chan_spec;
  35         u8 dac_reg_offset;
  36         bool use_ext_ref_voltage;
  37 };
  38
  39 struct mcp4725_data {
  40         struct i2c_client *client;
  41         unsigned ref_mode;
  42         bool vref_buffered;
  43         u16 dac_value;
  44         bool powerdown;
  45         unsigned powerdown_mode;
  46         struct regulator *vdd_reg;
  47         struct regulator *vref_reg;
  48 };
  49
  50 static int mcp4725_suspend(struct device *dev)
  51 {
  52         struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
  53                 to_i2c_client(dev)));
  54         u8 outbuf[2];
  55         int ret;
  56
  57         outbuf[0] = (data->powerdown_mode + 1) << 4;
  58         outbuf[1] = 0;
  59         data->powerdown = true;
  60
  61         ret = i2c_master_send(data->client, outbuf, 2);
  62         if (ret < 0)
  63                 return ret;
  64         else if (ret != 2)
  65                 return -EIO;
  66         return 0;
  67 }
  68
  69 static int mcp4725_resume(struct device *dev)
  70 {
  71         struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
  72                 to_i2c_client(dev)));
  73         u8 outbuf[2];
  74         int ret;
  75
  76         /* restore previous DAC value */
  77         outbuf[0] = (data->dac_value >> 8) & 0xf;
  78         outbuf[1] = data->dac_value & 0xff;
  79         data->powerdown = false;
  80
  81         ret = i2c_master_send(data->client, outbuf, 2);
  82         if (ret < 0)
  83                 return ret;
  84         else if (ret != 2)
  85                 return -EIO;
  86         return 0;
  87 }
  88 static DEFINE_SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend,
  89                                 mcp4725_resume);
  90
  91 static ssize_t mcp4725_store_eeprom(struct device *dev,
  92         struct device_attribute *attr, const char *buf, size_t len)
  93 {
  94         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
  95         struct mcp4725_data *data = iio_priv(indio_dev);
  96         int tries = 20;
  97         u8 inoutbuf[3];
  98         bool state;
  99         int ret;
 100
 101         ret = kstrtobool(buf, &state);
 102         if (ret < 0)
 103                 return ret;
 104
 105         if (!state)
 106                 return 0;
 107
 108         inoutbuf[0] = 0x60; /* write EEPROM */
 109         inoutbuf[0] |= data->ref_mode << 3;
 110         inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
 111         inoutbuf[1] = data->dac_value >> 4;
 112         inoutbuf[2] = (data->dac_value & 0xf) << 4;
 113
 114         ret = i2c_master_send(data->client, inoutbuf, 3);
 115         if (ret < 0)
 116                 return ret;
 117         else if (ret != 3)
 118                 return -EIO;
 119
 120         /* wait for write complete, takes up to 50ms */
 121         while (tries--) {
 122                 msleep(20);
 123                 ret = i2c_master_recv(data->client, inoutbuf, 3);
 124                 if (ret < 0)
 125                         return ret;
 126                 else if (ret != 3)
 127                         return -EIO;
 128
 129                 if (inoutbuf[0] & 0x80)
 130                         break;
 131         }
 132
 133         if (tries < 0) {
 134                 dev_err(&data->client->dev,
 135                         "mcp4725_store_eeprom() failed, incomplete\n");
 136                 return -EIO;
 137         }
 138
 139         return len;
 140 }
 141
 142 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
 143
 144 static struct attribute *mcp4725_attributes[] = {
 145         &iio_dev_attr_store_eeprom.dev_attr.attr,
 146         NULL,
 147 };
 148
 149 static const struct attribute_group mcp4725_attribute_group = {
 150         .attrs = mcp4725_attributes,
 151 };
 152
 153 static const char * const mcp4725_powerdown_modes[] = {
 154         "1kohm_to_gnd",
 155         "100kohm_to_gnd",
 156         "500kohm_to_gnd"
 157 };
 158
 159 static const char * const mcp4726_powerdown_modes[] = {
 160         "1kohm_to_gnd",
 161         "125kohm_to_gnd",
 162         "640kohm_to_gnd"
 163 };
 164
 165 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
 166         const struct iio_chan_spec *chan)
 167 {
 168         struct mcp4725_data *data = iio_priv(indio_dev);
 169
 170         return data->powerdown_mode;
 171 }
 172
 173 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
 174         const struct iio_chan_spec *chan, unsigned mode)
 175 {
 176         struct mcp4725_data *data = iio_priv(indio_dev);
 177
 178         data->powerdown_mode = mode;
 179
 180         return 0;
 181 }
 182
 183 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
 184         uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 185 {
 186         struct mcp4725_data *data = iio_priv(indio_dev);
 187
 188         return sysfs_emit(buf, "%d\n", data->powerdown);
 189 }
 190
 191 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
 192          uintptr_t private, const struct iio_chan_spec *chan,
 193          const char *buf, size_t len)
 194 {
 195         struct mcp4725_data *data = iio_priv(indio_dev);
 196         bool state;
 197         int ret;
 198
 199         ret = kstrtobool(buf, &state);
 200         if (ret)
 201                 return ret;
 202
 203         if (state)
 204                 ret = mcp4725_suspend(&data->client->dev);
 205         else
 206                 ret = mcp4725_resume(&data->client->dev);
 207         if (ret < 0)
 208                 return ret;
 209
 210         return len;
 211 }
 212
 213 enum chip_id {
 214         MCP4725,
 215         MCP4726,
 216 };
 217
 218 static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
 219         [MCP4725] = {
 220                 .items = mcp4725_powerdown_modes,
 221                 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
 222                 .get = mcp4725_get_powerdown_mode,
 223                 .set = mcp4725_set_powerdown_mode,
 224         },
 225         [MCP4726] = {
 226                 .items = mcp4726_powerdown_modes,
 227                 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
 228                 .get = mcp4725_get_powerdown_mode,
 229                 .set = mcp4725_set_powerdown_mode,
 230         },
 231 };
 232
 233 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
 234         {
 235                 .name = "powerdown",
 236                 .read = mcp4725_read_powerdown,
 237                 .write = mcp4725_write_powerdown,
 238                 .shared = IIO_SEPARATE,
 239         },
 240         IIO_ENUM("powerdown_mode", IIO_SEPARATE,
 241                         &mcp472x_powerdown_mode_enum[MCP4725]),
 242         IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
 243                            &mcp472x_powerdown_mode_enum[MCP4725]),
 244         { },
 245 };
 246
 247 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
 248         {
 249                 .name = "powerdown",
 250                 .read = mcp4725_read_powerdown,
 251                 .write = mcp4725_write_powerdown,
 252                 .shared = IIO_SEPARATE,
 253         },
 254         IIO_ENUM("powerdown_mode", IIO_SEPARATE,
 255                         &mcp472x_powerdown_mode_enum[MCP4726]),
 256         IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
 257                            &mcp472x_powerdown_mode_enum[MCP4726]),
 258         { },
 259 };
 260
 261 static const struct iio_chan_spec mcp472x_channel[] = {
 262         [MCP4725] = {
 263                 .type           = IIO_VOLTAGE,
 264                 .indexed        = 1,
 265                 .output         = 1,
 266                 .channel        = 0,
 267                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 268                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 269                 .ext_info       = mcp4725_ext_info,
 270         },
 271         [MCP4726] = {
 272                 .type           = IIO_VOLTAGE,
 273                 .indexed        = 1,
 274                 .output         = 1,
 275                 .channel        = 0,
 276                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 277                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 278                 .ext_info       = mcp4726_ext_info,
 279         },
 280 };
 281
 282 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
 283 {
 284         struct mcp4725_data *data = iio_priv(indio_dev);
 285         u8 outbuf[2];
 286         int ret;
 287
 288         if (val >= (1 << 12) || val < 0)
 289                 return -EINVAL;
 290
 291         outbuf[0] = (val >> 8) & 0xf;
 292         outbuf[1] = val & 0xff;
 293
 294         ret = i2c_master_send(data->client, outbuf, 2);
 295         if (ret < 0)
 296                 return ret;
 297         else if (ret != 2)
 298                 return -EIO;
 299         else
 300                 return 0;
 301 }
 302
 303 static int mcp4726_set_cfg(struct iio_dev *indio_dev)
 304 {
 305         struct mcp4725_data *data = iio_priv(indio_dev);
 306         u8 outbuf[3];
 307         int ret;
 308
 309         outbuf[0] = 0x40;
 310         outbuf[0] |= data->ref_mode << 3;
 311         if (data->powerdown)
 312                 outbuf[0] |= data->powerdown << 1;
 313         outbuf[1] = data->dac_value >> 4;
 314         outbuf[2] = (data->dac_value & 0xf) << 4;
 315
 316         ret = i2c_master_send(data->client, outbuf, 3);
 317         if (ret < 0)
 318                 return ret;
 319         else if (ret != 3)
 320                 return -EIO;
 321         else
 322                 return 0;
 323 }
 324
 325 static int mcp4725_read_raw(struct iio_dev *indio_dev,
 326                            struct iio_chan_spec const *chan,
 327                            int *val, int *val2, long mask)
 328 {
 329         struct mcp4725_data *data = iio_priv(indio_dev);
 330         int ret;
 331
 332         switch (mask) {
 333         case IIO_CHAN_INFO_RAW:
 334                 *val = data->dac_value;
 335                 return IIO_VAL_INT;
 336         case IIO_CHAN_INFO_SCALE:
 337                 if (data->ref_mode == MCP472X_REF_VDD)
 338                         ret = regulator_get_voltage(data->vdd_reg);
 339                 else
 340                         ret = regulator_get_voltage(data->vref_reg);
 341
 342                 if (ret < 0)
 343                         return ret;
 344
 345                 *val = ret / 1000;
 346                 *val2 = 12;
 347                 return IIO_VAL_FRACTIONAL_LOG2;
 348         }
 349         return -EINVAL;
 350 }
 351
 352 static int mcp4725_write_raw(struct iio_dev *indio_dev,
 353                                struct iio_chan_spec const *chan,
 354                                int val, int val2, long mask)
 355 {
 356         struct mcp4725_data *data = iio_priv(indio_dev);
 357         int ret;
 358
 359         switch (mask) {
 360         case IIO_CHAN_INFO_RAW:
 361                 ret = mcp4725_set_value(indio_dev, val);
 362                 data->dac_value = val;
 363                 break;
 364         default:
 365                 ret = -EINVAL;
 366                 break;
 367         }
 368
 369         return ret;
 370 }
 371
 372 static const struct iio_info mcp4725_info = {
 373         .read_raw = mcp4725_read_raw,
 374         .write_raw = mcp4725_write_raw,
 375         .attrs = &mcp4725_attribute_group,
 376 };
 377
 378 static int mcp4725_probe_dt(struct device *dev,
 379                             struct mcp4725_platform_data *pdata)
 380 {
 381         /* check if is the vref-supply defined */
 382         pdata->use_vref = device_property_read_bool(dev, "vref-supply");
 383         pdata->vref_buffered =
 384                 device_property_read_bool(dev, "microchip,vref-buffered");
 385
 386         return 0;
 387 }
 388
 389 static int mcp4725_probe(struct i2c_client *client)
 390 {
 391         const struct i2c_device_id *id = i2c_client_get_device_id(client);
 392         const struct mcp4725_chip_info *info;
 393         struct mcp4725_data *data;
 394         struct iio_dev *indio_dev;
 395         struct mcp4725_platform_data *pdata, pdata_dt;
 396         u8 inbuf[4];
 397         u8 pd;
 398         u8 ref;
 399         int err;
 400
 401         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 402         if (indio_dev == NULL)
 403                 return -ENOMEM;
 404         data = iio_priv(indio_dev);
 405         i2c_set_clientdata(client, indio_dev);
 406         data->client = client;
 407         info = i2c_get_match_data(client);
 408         pdata = dev_get_platdata(&client->dev);
 409
 410         if (!pdata) {
 411                 err = mcp4725_probe_dt(&client->dev, &pdata_dt);
 412                 if (err) {
 413                         dev_err(&client->dev,
 414                                 "invalid platform or devicetree data");
 415                         return err;
 416                 }
 417                 pdata = &pdata_dt;
 418         }
 419
 420         if (info->use_ext_ref_voltage && pdata->use_vref) {
 421                 dev_err(&client->dev,
 422                         "external reference is unavailable on MCP4725");
 423                 return -EINVAL;
 424         }
 425
 426         if (!pdata->use_vref && pdata->vref_buffered) {
 427                 dev_err(&client->dev,
 428                         "buffering is unavailable on the internal reference");
 429                 return -EINVAL;
 430         }
 431
 432         if (!pdata->use_vref)
 433                 data->ref_mode = MCP472X_REF_VDD;
 434         else
 435                 data->ref_mode = pdata->vref_buffered ?
 436                         MCP472X_REF_VREF_BUFFERED :
 437                         MCP472X_REF_VREF_UNBUFFERED;
 438
 439         data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
 440         if (IS_ERR(data->vdd_reg))
 441                 return PTR_ERR(data->vdd_reg);
 442
 443         err = regulator_enable(data->vdd_reg);
 444         if (err)
 445                 return err;
 446
 447         if (pdata->use_vref) {
 448                 data->vref_reg = devm_regulator_get(&client->dev, "vref");
 449                 if (IS_ERR(data->vref_reg)) {
 450                         err = PTR_ERR(data->vref_reg);
 451                         goto err_disable_vdd_reg;
 452                 }
 453
 454                 err = regulator_enable(data->vref_reg);
 455                 if (err)
 456                         goto err_disable_vdd_reg;
 457         }
 458
 459         indio_dev->name = id->name;
 460         indio_dev->info = &mcp4725_info;
 461         indio_dev->channels = info->chan_spec;
 462         indio_dev->num_channels = 1;
 463         indio_dev->modes = INDIO_DIRECT_MODE;
 464
 465         /* read current DAC value and settings */
 466         err = i2c_master_recv(client, inbuf, info->dac_reg_offset);
 467
 468         if (err < 0) {
 469                 dev_err(&client->dev, "failed to read DAC value");
 470                 goto err_disable_vref_reg;
 471         }
 472         pd = (inbuf[0] >> 1) & 0x3;
 473         data->powerdown = pd > 0;
 474         data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
 475         data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
 476         if (!info->use_ext_ref_voltage)
 477                 ref = (inbuf[3] >> 3) & 0x3;
 478
 479         if (!info->use_ext_ref_voltage && ref != data->ref_mode) {
 480                 dev_info(&client->dev,
 481                         "voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
 482                         data->ref_mode, ref, data->ref_mode);
 483                 err = mcp4726_set_cfg(indio_dev);
 484                 if (err < 0)
 485                         goto err_disable_vref_reg;
 486         }
 487
 488         err = iio_device_register(indio_dev);
 489         if (err)
 490                 goto err_disable_vref_reg;
 491
 492         return 0;
 493
 494 err_disable_vref_reg:
 495         if (data->vref_reg)
 496                 regulator_disable(data->vref_reg);
 497
 498 err_disable_vdd_reg:
 499         regulator_disable(data->vdd_reg);
 500
 501         return err;
 502 }
 503
 504 static void mcp4725_remove(struct i2c_client *client)
 505 {
 506         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 507         struct mcp4725_data *data = iio_priv(indio_dev);
 508
 509         iio_device_unregister(indio_dev);
 510
 511         if (data->vref_reg)
 512                 regulator_disable(data->vref_reg);
 513         regulator_disable(data->vdd_reg);
 514 }
 515
 516 static const struct mcp4725_chip_info mcp4725 = {
 517         .chan_spec = &mcp472x_channel[MCP4725],
 518         .dac_reg_offset = 3,
 519         .use_ext_ref_voltage = true,
 520 };
 521
 522 static const struct mcp4725_chip_info mcp4726 = {
 523         .chan_spec = &mcp472x_channel[MCP4726],
 524         .dac_reg_offset = 4,
 525 };
 526
 527 static const struct i2c_device_id mcp4725_id[] = {
 528         { "mcp4725", (kernel_ulong_t)&mcp4725 },
 529         { "mcp4726", (kernel_ulong_t)&mcp4726 },
 530         { }
 531 };
 532 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
 533
 534 static const struct of_device_id mcp4725_of_match[] = {
 535         {
 536                 .compatible = "microchip,mcp4725",
 537                 .data = &mcp4725
 538         },
 539         {
 540                 .compatible = "microchip,mcp4726",
 541                 .data = &mcp4726
 542         },
 543         { }
 544 };
 545 MODULE_DEVICE_TABLE(of, mcp4725_of_match);
 546
 547 static struct i2c_driver mcp4725_driver = {
 548         .driver = {
 549                 .name   = MCP4725_DRV_NAME,
 550                 .of_match_table = mcp4725_of_match,
 551                 .pm     = pm_sleep_ptr(&mcp4725_pm_ops),
 552         },
 553         .probe          = mcp4725_probe,
 554         .remove         = mcp4725_remove,
 555         .id_table       = mcp4725_id,
 556 };
 557 module_i2c_driver(mcp4725_driver);
 558
 559 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 560 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
 561 MODULE_LICENSE("GPL");