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