drivers/iio/dac/mcp4725.c

   1 /*
   2  * mcp4725.c - Support for Microchip MCP4725/6
   3  *
   4  * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
   5  *
   6  * Based on max517 by Roland Stigge <stigge@antcom.de>
   7  *
   8  * This file is subject to the terms and conditions of version 2 of
   9  * the GNU General Public License.  See the file COPYING in the main
  10  * directory of this archive for more details.
  11  *
  12  * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
  13  * (7-bit I2C slave address 0x60, the three LSBs can be configured in
  14  * hardware)
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/i2c.h>
  19 #include <linux/err.h>
  20 #include <linux/delay.h>
  21 #include <linux/regulator/consumer.h>
  22 #include <linux/of_device.h>
  23 #include <linux/of.h>
  24
  25 #include <linux/iio/iio.h>
  26 #include <linux/iio/sysfs.h>
  27
  28 #include <linux/iio/dac/mcp4725.h>
  29
  30 #define MCP4725_DRV_NAME "mcp4725"
  31
  32 #define MCP472X_REF_VDD                 0x00
  33 #define MCP472X_REF_VREF_UNBUFFERED     0x02
  34 #define MCP472X_REF_VREF_BUFFERED       0x03
  35
  36 struct mcp4725_data {
  37         struct i2c_client *client;
  38         int id;
  39         unsigned ref_mode;
  40         bool vref_buffered;
  41         u16 dac_value;
  42         bool powerdown;
  43         unsigned powerdown_mode;
  44         struct regulator *vdd_reg;
  45         struct regulator *vref_reg;
  46 };
  47
  48 static int mcp4725_suspend(struct device *dev)
  49 {
  50         struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
  51                 to_i2c_client(dev)));
  52         u8 outbuf[2];
  53
  54         outbuf[0] = (data->powerdown_mode + 1) << 4;
  55         outbuf[1] = 0;
  56         data->powerdown = true;
  57
  58         return i2c_master_send(data->client, outbuf, 2);
  59 }
  60
  61 static int mcp4725_resume(struct device *dev)
  62 {
  63         struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
  64                 to_i2c_client(dev)));
  65         u8 outbuf[2];
  66
  67         /* restore previous DAC value */
  68         outbuf[0] = (data->dac_value >> 8) & 0xf;
  69         outbuf[1] = data->dac_value & 0xff;
  70         data->powerdown = false;
  71
  72         return i2c_master_send(data->client, outbuf, 2);
  73 }
  74
  75 #ifdef CONFIG_PM_SLEEP
  76 static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
  77 #define MCP4725_PM_OPS (&mcp4725_pm_ops)
  78 #else
  79 #define MCP4725_PM_OPS NULL
  80 #endif
  81
  82 static ssize_t mcp4725_store_eeprom(struct device *dev,
  83         struct device_attribute *attr, const char *buf, size_t len)
  84 {
  85         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
  86         struct mcp4725_data *data = iio_priv(indio_dev);
  87         int tries = 20;
  88         u8 inoutbuf[3];
  89         bool state;
  90         int ret;
  91
  92         ret = strtobool(buf, &state);
  93         if (ret < 0)
  94                 return ret;
  95
  96         if (!state)
  97                 return 0;
  98
  99         inoutbuf[0] = 0x60; /* write EEPROM */
 100         inoutbuf[0] |= data->ref_mode << 3;
 101         inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
 102         inoutbuf[1] = data->dac_value >> 4;
 103         inoutbuf[2] = (data->dac_value & 0xf) << 4;
 104
 105         ret = i2c_master_send(data->client, inoutbuf, 3);
 106         if (ret < 0)
 107                 return ret;
 108         else if (ret != 3)
 109                 return -EIO;
 110
 111         /* wait for write complete, takes up to 50ms */
 112         while (tries--) {
 113                 msleep(20);
 114                 ret = i2c_master_recv(data->client, inoutbuf, 3);
 115                 if (ret < 0)
 116                         return ret;
 117                 else if (ret != 3)
 118                         return -EIO;
 119
 120                 if (inoutbuf[0] & 0x80)
 121                         break;
 122         }
 123
 124         if (tries < 0) {
 125                 dev_err(&data->client->dev,
 126                         "mcp4725_store_eeprom() failed, incomplete\n");
 127                 return -EIO;
 128         }
 129
 130         return len;
 131 }
 132
 133 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
 134
 135 static struct attribute *mcp4725_attributes[] = {
 136         &iio_dev_attr_store_eeprom.dev_attr.attr,
 137         NULL,
 138 };
 139
 140 static const struct attribute_group mcp4725_attribute_group = {
 141         .attrs = mcp4725_attributes,
 142 };
 143
 144 static const char * const mcp4725_powerdown_modes[] = {
 145         "1kohm_to_gnd",
 146         "100kohm_to_gnd",
 147         "500kohm_to_gnd"
 148 };
 149
 150 static const char * const mcp4726_powerdown_modes[] = {
 151         "1kohm_to_gnd",
 152         "125kohm_to_gnd",
 153         "640kohm_to_gnd"
 154 };
 155
 156 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
 157         const struct iio_chan_spec *chan)
 158 {
 159         struct mcp4725_data *data = iio_priv(indio_dev);
 160
 161         return data->powerdown_mode;
 162 }
 163
 164 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
 165         const struct iio_chan_spec *chan, unsigned mode)
 166 {
 167         struct mcp4725_data *data = iio_priv(indio_dev);
 168
 169         data->powerdown_mode = mode;
 170
 171         return 0;
 172 }
 173
 174 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
 175         uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 176 {
 177         struct mcp4725_data *data = iio_priv(indio_dev);
 178
 179         return sprintf(buf, "%d\n", data->powerdown);
 180 }
 181
 182 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
 183          uintptr_t private, const struct iio_chan_spec *chan,
 184          const char *buf, size_t len)
 185 {
 186         struct mcp4725_data *data = iio_priv(indio_dev);
 187         bool state;
 188         int ret;
 189
 190         ret = strtobool(buf, &state);
 191         if (ret)
 192                 return ret;
 193
 194         if (state)
 195                 ret = mcp4725_suspend(&data->client->dev);
 196         else
 197                 ret = mcp4725_resume(&data->client->dev);
 198         if (ret < 0)
 199                 return ret;
 200
 201         return len;
 202 }
 203
 204 enum chip_id {
 205         MCP4725,
 206         MCP4726,
 207 };
 208
 209 static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
 210         [MCP4725] = {
 211                 .items = mcp4725_powerdown_modes,
 212                 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
 213                 .get = mcp4725_get_powerdown_mode,
 214                 .set = mcp4725_set_powerdown_mode,
 215         },
 216         [MCP4726] = {
 217                 .items = mcp4726_powerdown_modes,
 218                 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
 219                 .get = mcp4725_get_powerdown_mode,
 220                 .set = mcp4725_set_powerdown_mode,
 221         },
 222 };
 223
 224 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
 225         {
 226                 .name = "powerdown",
 227                 .read = mcp4725_read_powerdown,
 228                 .write = mcp4725_write_powerdown,
 229                 .shared = IIO_SEPARATE,
 230         },
 231         IIO_ENUM("powerdown_mode", IIO_SEPARATE,
 232                         &mcp472x_powerdown_mode_enum[MCP4725]),
 233         IIO_ENUM_AVAILABLE("powerdown_mode",
 234                         &mcp472x_powerdown_mode_enum[MCP4725]),
 235         { },
 236 };
 237
 238 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
 239         {
 240                 .name = "powerdown",
 241                 .read = mcp4725_read_powerdown,
 242                 .write = mcp4725_write_powerdown,
 243                 .shared = IIO_SEPARATE,
 244         },
 245         IIO_ENUM("powerdown_mode", IIO_SEPARATE,
 246                         &mcp472x_powerdown_mode_enum[MCP4726]),
 247         IIO_ENUM_AVAILABLE("powerdown_mode",
 248                         &mcp472x_powerdown_mode_enum[MCP4726]),
 249         { },
 250 };
 251
 252 static const struct iio_chan_spec mcp472x_channel[] = {
 253         [MCP4725] = {
 254                 .type           = IIO_VOLTAGE,
 255                 .indexed        = 1,
 256                 .output         = 1,
 257                 .channel        = 0,
 258                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 259                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 260                 .ext_info       = mcp4725_ext_info,
 261         },
 262         [MCP4726] = {
 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       = mcp4726_ext_info,
 270         },
 271 };
 272
 273 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
 274 {
 275         struct mcp4725_data *data = iio_priv(indio_dev);
 276         u8 outbuf[2];
 277         int ret;
 278
 279         if (val >= (1 << 12) || val < 0)
 280                 return -EINVAL;
 281
 282         outbuf[0] = (val >> 8) & 0xf;
 283         outbuf[1] = val & 0xff;
 284
 285         ret = i2c_master_send(data->client, outbuf, 2);
 286         if (ret < 0)
 287                 return ret;
 288         else if (ret != 2)
 289                 return -EIO;
 290         else
 291                 return 0;
 292 }
 293
 294 static int mcp4726_set_cfg(struct iio_dev *indio_dev)
 295 {
 296         struct mcp4725_data *data = iio_priv(indio_dev);
 297         u8 outbuf[3];
 298         int ret;
 299
 300         outbuf[0] = 0x40;
 301         outbuf[0] |= data->ref_mode << 3;
 302         if (data->powerdown)
 303                 outbuf[0] |= data->powerdown << 1;
 304         outbuf[1] = data->dac_value >> 4;
 305         outbuf[2] = (data->dac_value & 0xf) << 4;
 306
 307         ret = i2c_master_send(data->client, outbuf, 3);
 308         if (ret < 0)
 309                 return ret;
 310         else if (ret != 3)
 311                 return -EIO;
 312         else
 313                 return 0;
 314 }
 315
 316 static int mcp4725_read_raw(struct iio_dev *indio_dev,
 317                            struct iio_chan_spec const *chan,
 318                            int *val, int *val2, long mask)
 319 {
 320         struct mcp4725_data *data = iio_priv(indio_dev);
 321         int ret;
 322
 323         switch (mask) {
 324         case IIO_CHAN_INFO_RAW:
 325                 *val = data->dac_value;
 326                 return IIO_VAL_INT;
 327         case IIO_CHAN_INFO_SCALE:
 328                 if (data->ref_mode == MCP472X_REF_VDD)
 329                         ret = regulator_get_voltage(data->vdd_reg);
 330                 else
 331                         ret = regulator_get_voltage(data->vref_reg);
 332
 333                 if (ret < 0)
 334                         return ret;
 335
 336                 *val = ret / 1000;
 337                 *val2 = 12;
 338                 return IIO_VAL_FRACTIONAL_LOG2;
 339         }
 340         return -EINVAL;
 341 }
 342
 343 static int mcp4725_write_raw(struct iio_dev *indio_dev,
 344                                struct iio_chan_spec const *chan,
 345                                int val, int val2, long mask)
 346 {
 347         struct mcp4725_data *data = iio_priv(indio_dev);
 348         int ret;
 349
 350         switch (mask) {
 351         case IIO_CHAN_INFO_RAW:
 352                 ret = mcp4725_set_value(indio_dev, val);
 353                 data->dac_value = val;
 354                 break;
 355         default:
 356                 ret = -EINVAL;
 357                 break;
 358         }
 359
 360         return ret;
 361 }
 362
 363 static const struct iio_info mcp4725_info = {
 364         .read_raw = mcp4725_read_raw,
 365         .write_raw = mcp4725_write_raw,
 366         .attrs = &mcp4725_attribute_group,
 367 };
 368
 369 #ifdef CONFIG_OF
 370 static int mcp4725_probe_dt(struct device *dev,
 371                             struct mcp4725_platform_data *pdata)
 372 {
 373         struct device_node *np = dev->of_node;
 374
 375         if (!np)
 376                 return -ENODEV;
 377
 378         /* check if is the vref-supply defined */
 379         pdata->use_vref = of_property_read_bool(np, "vref-supply");
 380         pdata->vref_buffered =
 381                 of_property_read_bool(np, "microchip,vref-buffered");
 382
 383         return 0;
 384 }
 385 #else
 386 static int mcp4725_probe_dt(struct device *dev,
 387                             struct mcp4725_platform_data *platform_data)
 388 {
 389         return -ENODEV;
 390 }
 391 #endif
 392
 393 static int mcp4725_probe(struct i2c_client *client,
 394                          const struct i2c_device_id *id)
 395 {
 396         struct mcp4725_data *data;
 397         struct iio_dev *indio_dev;
 398         struct mcp4725_platform_data *pdata, pdata_dt;
 399         u8 inbuf[4];
 400         u8 pd;
 401         u8 ref;
 402         int err;
 403
 404         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 405         if (indio_dev == NULL)
 406                 return -ENOMEM;
 407         data = iio_priv(indio_dev);
 408         i2c_set_clientdata(client, indio_dev);
 409         data->client = client;
 410         if (client->dev.of_node)
 411                 data->id = (enum chip_id)of_device_get_match_data(&client->dev);
 412         else
 413                 data->id = id->driver_data;
 414         pdata = dev_get_platdata(&client->dev);
 415
 416         if (!pdata) {
 417                 err = mcp4725_probe_dt(&client->dev, &pdata_dt);
 418                 if (err) {
 419                         dev_err(&client->dev,
 420                                 "invalid platform or devicetree data");
 421                         return err;
 422                 }
 423                 pdata = &pdata_dt;
 424         }
 425
 426         if (data->id == MCP4725 && pdata->use_vref) {
 427                 dev_err(&client->dev,
 428                         "external reference is unavailable on MCP4725");
 429                 return -EINVAL;
 430         }
 431
 432         if (!pdata->use_vref && pdata->vref_buffered) {
 433                 dev_err(&client->dev,
 434                         "buffering is unavailable on the internal reference");
 435                 return -EINVAL;
 436         }
 437
 438         if (!pdata->use_vref)
 439                 data->ref_mode = MCP472X_REF_VDD;
 440         else
 441                 data->ref_mode = pdata->vref_buffered ?
 442                         MCP472X_REF_VREF_BUFFERED :
 443                         MCP472X_REF_VREF_UNBUFFERED;
 444
 445         data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
 446         if (IS_ERR(data->vdd_reg))
 447                 return PTR_ERR(data->vdd_reg);
 448
 449         err = regulator_enable(data->vdd_reg);
 450         if (err)
 451                 return err;
 452
 453         if (pdata->use_vref) {
 454                 data->vref_reg = devm_regulator_get(&client->dev, "vref");
 455                 if (IS_ERR(data->vref_reg)) {
 456                         err = PTR_ERR(data->vref_reg);
 457                         goto err_disable_vdd_reg;
 458                 }
 459
 460                 err = regulator_enable(data->vref_reg);
 461                 if (err)
 462                         goto err_disable_vdd_reg;
 463         }
 464
 465         indio_dev->dev.parent = &client->dev;
 466         indio_dev->name = id->name;
 467         indio_dev->info = &mcp4725_info;
 468         indio_dev->channels = &mcp472x_channel[id->driver_data];
 469         indio_dev->num_channels = 1;
 470         indio_dev->modes = INDIO_DIRECT_MODE;
 471
 472         /* read current DAC value and settings */
 473         err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4);
 474
 475         if (err < 0) {
 476                 dev_err(&client->dev, "failed to read DAC value");
 477                 goto err_disable_vref_reg;
 478         }
 479         pd = (inbuf[0] >> 1) & 0x3;
 480         data->powerdown = pd > 0;
 481         data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
 482         data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
 483         if (data->id == MCP4726)
 484                 ref = (inbuf[3] >> 3) & 0x3;
 485
 486         if (data->id == MCP4726 && ref != data->ref_mode) {
 487                 dev_info(&client->dev,
 488                         "voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
 489                         data->ref_mode, ref, data->ref_mode);
 490                 err = mcp4726_set_cfg(indio_dev);
 491                 if (err < 0)
 492                         goto err_disable_vref_reg;
 493         }
 494
 495         err = iio_device_register(indio_dev);
 496         if (err)
 497                 goto err_disable_vref_reg;
 498
 499         return 0;
 500
 501 err_disable_vref_reg:
 502         if (data->vref_reg)
 503                 regulator_disable(data->vref_reg);
 504
 505 err_disable_vdd_reg:
 506         regulator_disable(data->vdd_reg);
 507
 508         return err;
 509 }
 510
 511 static int mcp4725_remove(struct i2c_client *client)
 512 {
 513         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 514         struct mcp4725_data *data = iio_priv(indio_dev);
 515
 516         iio_device_unregister(indio_dev);
 517
 518         if (data->vref_reg)
 519                 regulator_disable(data->vref_reg);
 520         regulator_disable(data->vdd_reg);
 521
 522         return 0;
 523 }
 524
 525 static const struct i2c_device_id mcp4725_id[] = {
 526         { "mcp4725", MCP4725 },
 527         { "mcp4726", MCP4726 },
 528         { }
 529 };
 530 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
 531
 532 #ifdef CONFIG_OF
 533 static const struct of_device_id mcp4725_of_match[] = {
 534         {
 535                 .compatible = "microchip,mcp4725",
 536                 .data = (void *)MCP4725
 537         },
 538         {
 539                 .compatible = "microchip,mcp4726",
 540                 .data = (void *)MCP4726
 541         },
 542         { }
 543 };
 544 MODULE_DEVICE_TABLE(of, mcp4725_of_match);
 545 #endif
 546
 547 static struct i2c_driver mcp4725_driver = {
 548         .driver = {
 549                 .name   = MCP4725_DRV_NAME,
 550                 .of_match_table = of_match_ptr(mcp4725_of_match),
 551                 .pm     = 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");