iio/dac/mcp4725.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * mcp4725.c - Support for Microchip MCP4725/6
0004  *
0005  * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
0006  *
0007  * Based on max517 by Roland Stigge <stigge@antcom.de>
0008  *
0009  * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
0010  * (7-bit I2C slave address 0x60, the three LSBs can be configured in
0011  * hardware)
0012  */
0013
0014 #include <linux/module.h>
0015 #include <linux/i2c.h>
0016 #include <linux/err.h>
0017 #include <linux/delay.h>
0018 #include <linux/regulator/consumer.h>
0019 #include <linux/mod_devicetable.h>
0020 #include <linux/property.h>
0021
0022 #include <linux/iio/iio.h>
0023 #include <linux/iio/sysfs.h>
0024
0025 #include <linux/iio/dac/mcp4725.h>
0026
0027 #define MCP4725_DRV_NAME "mcp4725"
0028
0029 #define MCP472X_REF_VDD         0x00
0030 #define MCP472X_REF_VREF_UNBUFFERED 0x02
0031 #define MCP472X_REF_VREF_BUFFERED   0x03
0032
0033 struct mcp4725_data {
0034     struct i2c_client *client;
0035     int id;
0036     unsigned ref_mode;
0037     bool vref_buffered;
0038     u16 dac_value;
0039     bool powerdown;
0040     unsigned powerdown_mode;
0041     struct regulator *vdd_reg;
0042     struct regulator *vref_reg;
0043 };
0044
0045 static int mcp4725_suspend(struct device *dev)
0046 {
0047     struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
0048         to_i2c_client(dev)));
0049     u8 outbuf[2];
0050
0051     outbuf[0] = (data->powerdown_mode + 1) << 4;
0052     outbuf[1] = 0;
0053     data->powerdown = true;
0054
0055     return i2c_master_send(data->client, outbuf, 2);
0056 }
0057
0058 static int mcp4725_resume(struct device *dev)
0059 {
0060     struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
0061         to_i2c_client(dev)));
0062     u8 outbuf[2];
0063
0064     /* restore previous DAC value */
0065     outbuf[0] = (data->dac_value >> 8) & 0xf;
0066     outbuf[1] = data->dac_value & 0xff;
0067     data->powerdown = false;
0068
0069     return i2c_master_send(data->client, outbuf, 2);
0070 }
0071 static DEFINE_SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend,
0072                 mcp4725_resume);
0073
0074 static ssize_t mcp4725_store_eeprom(struct device *dev,
0075     struct device_attribute *attr, const char *buf, size_t len)
0076 {
0077     struct iio_dev *indio_dev = dev_to_iio_dev(dev);
0078     struct mcp4725_data *data = iio_priv(indio_dev);
0079     int tries = 20;
0080     u8 inoutbuf[3];
0081     bool state;
0082     int ret;
0083
0084     ret = kstrtobool(buf, &state);
0085     if (ret < 0)
0086         return ret;
0087
0088     if (!state)
0089         return 0;
0090
0091     inoutbuf[0] = 0x60; /* write EEPROM */
0092     inoutbuf[0] |= data->ref_mode << 3;
0093     inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
0094     inoutbuf[1] = data->dac_value >> 4;
0095     inoutbuf[2] = (data->dac_value & 0xf) << 4;
0096
0097     ret = i2c_master_send(data->client, inoutbuf, 3);
0098     if (ret < 0)
0099         return ret;
0100     else if (ret != 3)
0101         return -EIO;
0102
0103     /* wait for write complete, takes up to 50ms */
0104     while (tries--) {
0105         msleep(20);
0106         ret = i2c_master_recv(data->client, inoutbuf, 3);
0107         if (ret < 0)
0108             return ret;
0109         else if (ret != 3)
0110             return -EIO;
0111
0112         if (inoutbuf[0] & 0x80)
0113             break;
0114     }
0115
0116     if (tries < 0) {
0117         dev_err(&data->client->dev,
0118             "mcp4725_store_eeprom() failed, incomplete\n");
0119         return -EIO;
0120     }
0121
0122     return len;
0123 }
0124
0125 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
0126
0127 static struct attribute *mcp4725_attributes[] = {
0128     &iio_dev_attr_store_eeprom.dev_attr.attr,
0129     NULL,
0130 };
0131
0132 static const struct attribute_group mcp4725_attribute_group = {
0133     .attrs = mcp4725_attributes,
0134 };
0135
0136 static const char * const mcp4725_powerdown_modes[] = {
0137     "1kohm_to_gnd",
0138     "100kohm_to_gnd",
0139     "500kohm_to_gnd"
0140 };
0141
0142 static const char * const mcp4726_powerdown_modes[] = {
0143     "1kohm_to_gnd",
0144     "125kohm_to_gnd",
0145     "640kohm_to_gnd"
0146 };
0147
0148 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
0149     const struct iio_chan_spec *chan)
0150 {
0151     struct mcp4725_data *data = iio_priv(indio_dev);
0152
0153     return data->powerdown_mode;
0154 }
0155
0156 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
0157     const struct iio_chan_spec *chan, unsigned mode)
0158 {
0159     struct mcp4725_data *data = iio_priv(indio_dev);
0160
0161     data->powerdown_mode = mode;
0162
0163     return 0;
0164 }
0165
0166 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
0167     uintptr_t private, const struct iio_chan_spec *chan, char *buf)
0168 {
0169     struct mcp4725_data *data = iio_priv(indio_dev);
0170
0171     return sysfs_emit(buf, "%d\n", data->powerdown);
0172 }
0173
0174 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
0175      uintptr_t private, const struct iio_chan_spec *chan,
0176      const char *buf, size_t len)
0177 {
0178     struct mcp4725_data *data = iio_priv(indio_dev);
0179     bool state;
0180     int ret;
0181
0182     ret = kstrtobool(buf, &state);
0183     if (ret)
0184         return ret;
0185
0186     if (state)
0187         ret = mcp4725_suspend(&data->client->dev);
0188     else
0189         ret = mcp4725_resume(&data->client->dev);
0190     if (ret < 0)
0191         return ret;
0192
0193     return len;
0194 }
0195
0196 enum chip_id {
0197     MCP4725,
0198     MCP4726,
0199 };
0200
0201 static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
0202     [MCP4725] = {
0203         .items = mcp4725_powerdown_modes,
0204         .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
0205         .get = mcp4725_get_powerdown_mode,
0206         .set = mcp4725_set_powerdown_mode,
0207     },
0208     [MCP4726] = {
0209         .items = mcp4726_powerdown_modes,
0210         .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
0211         .get = mcp4725_get_powerdown_mode,
0212         .set = mcp4725_set_powerdown_mode,
0213     },
0214 };
0215
0216 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
0217     {
0218         .name = "powerdown",
0219         .read = mcp4725_read_powerdown,
0220         .write = mcp4725_write_powerdown,
0221         .shared = IIO_SEPARATE,
0222     },
0223     IIO_ENUM("powerdown_mode", IIO_SEPARATE,
0224             &mcp472x_powerdown_mode_enum[MCP4725]),
0225     IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
0226                &mcp472x_powerdown_mode_enum[MCP4725]),
0227     { },
0228 };
0229
0230 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
0231     {
0232         .name = "powerdown",
0233         .read = mcp4725_read_powerdown,
0234         .write = mcp4725_write_powerdown,
0235         .shared = IIO_SEPARATE,
0236     },
0237     IIO_ENUM("powerdown_mode", IIO_SEPARATE,
0238             &mcp472x_powerdown_mode_enum[MCP4726]),
0239     IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
0240                &mcp472x_powerdown_mode_enum[MCP4726]),
0241     { },
0242 };
0243
0244 static const struct iio_chan_spec mcp472x_channel[] = {
0245     [MCP4725] = {
0246         .type       = IIO_VOLTAGE,
0247         .indexed    = 1,
0248         .output     = 1,
0249         .channel    = 0,
0250         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
0251         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
0252         .ext_info   = mcp4725_ext_info,
0253     },
0254     [MCP4726] = {
0255         .type       = IIO_VOLTAGE,
0256         .indexed    = 1,
0257         .output     = 1,
0258         .channel    = 0,
0259         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
0260         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
0261         .ext_info   = mcp4726_ext_info,
0262     },
0263 };
0264
0265 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
0266 {
0267     struct mcp4725_data *data = iio_priv(indio_dev);
0268     u8 outbuf[2];
0269     int ret;
0270
0271     if (val >= (1 << 12) || val < 0)
0272         return -EINVAL;
0273
0274     outbuf[0] = (val >> 8) & 0xf;
0275     outbuf[1] = val & 0xff;
0276
0277     ret = i2c_master_send(data->client, outbuf, 2);
0278     if (ret < 0)
0279         return ret;
0280     else if (ret != 2)
0281         return -EIO;
0282     else
0283         return 0;
0284 }
0285
0286 static int mcp4726_set_cfg(struct iio_dev *indio_dev)
0287 {
0288     struct mcp4725_data *data = iio_priv(indio_dev);
0289     u8 outbuf[3];
0290     int ret;
0291
0292     outbuf[0] = 0x40;
0293     outbuf[0] |= data->ref_mode << 3;
0294     if (data->powerdown)
0295         outbuf[0] |= data->powerdown << 1;
0296     outbuf[1] = data->dac_value >> 4;
0297     outbuf[2] = (data->dac_value & 0xf) << 4;
0298
0299     ret = i2c_master_send(data->client, outbuf, 3);
0300     if (ret < 0)
0301         return ret;
0302     else if (ret != 3)
0303         return -EIO;
0304     else
0305         return 0;
0306 }
0307
0308 static int mcp4725_read_raw(struct iio_dev *indio_dev,
0309                struct iio_chan_spec const *chan,
0310                int *val, int *val2, long mask)
0311 {
0312     struct mcp4725_data *data = iio_priv(indio_dev);
0313     int ret;
0314
0315     switch (mask) {
0316     case IIO_CHAN_INFO_RAW:
0317         *val = data->dac_value;
0318         return IIO_VAL_INT;
0319     case IIO_CHAN_INFO_SCALE:
0320         if (data->ref_mode == MCP472X_REF_VDD)
0321             ret = regulator_get_voltage(data->vdd_reg);
0322         else
0323             ret = regulator_get_voltage(data->vref_reg);
0324
0325         if (ret < 0)
0326             return ret;
0327
0328         *val = ret / 1000;
0329         *val2 = 12;
0330         return IIO_VAL_FRACTIONAL_LOG2;
0331     }
0332     return -EINVAL;
0333 }
0334
0335 static int mcp4725_write_raw(struct iio_dev *indio_dev,
0336                    struct iio_chan_spec const *chan,
0337                    int val, int val2, long mask)
0338 {
0339     struct mcp4725_data *data = iio_priv(indio_dev);
0340     int ret;
0341
0342     switch (mask) {
0343     case IIO_CHAN_INFO_RAW:
0344         ret = mcp4725_set_value(indio_dev, val);
0345         data->dac_value = val;
0346         break;
0347     default:
0348         ret = -EINVAL;
0349         break;
0350     }
0351
0352     return ret;
0353 }
0354
0355 static const struct iio_info mcp4725_info = {
0356     .read_raw = mcp4725_read_raw,
0357     .write_raw = mcp4725_write_raw,
0358     .attrs = &mcp4725_attribute_group,
0359 };
0360
0361 static int mcp4725_probe_dt(struct device *dev,
0362                 struct mcp4725_platform_data *pdata)
0363 {
0364     /* check if is the vref-supply defined */
0365     pdata->use_vref = device_property_read_bool(dev, "vref-supply");
0366     pdata->vref_buffered =
0367         device_property_read_bool(dev, "microchip,vref-buffered");
0368
0369     return 0;
0370 }
0371
0372 static int mcp4725_probe(struct i2c_client *client,
0373              const struct i2c_device_id *id)
0374 {
0375     struct mcp4725_data *data;
0376     struct iio_dev *indio_dev;
0377     struct mcp4725_platform_data *pdata, pdata_dt;
0378     u8 inbuf[4];
0379     u8 pd;
0380     u8 ref;
0381     int err;
0382
0383     indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
0384     if (indio_dev == NULL)
0385         return -ENOMEM;
0386     data = iio_priv(indio_dev);
0387     i2c_set_clientdata(client, indio_dev);
0388     data->client = client;
0389     if (dev_fwnode(&client->dev))
0390         data->id = (uintptr_t)device_get_match_data(&client->dev);
0391     else
0392         data->id = id->driver_data;
0393     pdata = dev_get_platdata(&client->dev);
0394
0395     if (!pdata) {
0396         err = mcp4725_probe_dt(&client->dev, &pdata_dt);
0397         if (err) {
0398             dev_err(&client->dev,
0399                 "invalid platform or devicetree data");
0400             return err;
0401         }
0402         pdata = &pdata_dt;
0403     }
0404
0405     if (data->id == MCP4725 && pdata->use_vref) {
0406         dev_err(&client->dev,
0407             "external reference is unavailable on MCP4725");
0408         return -EINVAL;
0409     }
0410
0411     if (!pdata->use_vref && pdata->vref_buffered) {
0412         dev_err(&client->dev,
0413             "buffering is unavailable on the internal reference");
0414         return -EINVAL;
0415     }
0416
0417     if (!pdata->use_vref)
0418         data->ref_mode = MCP472X_REF_VDD;
0419     else
0420         data->ref_mode = pdata->vref_buffered ?
0421             MCP472X_REF_VREF_BUFFERED :
0422             MCP472X_REF_VREF_UNBUFFERED;
0423
0424     data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
0425     if (IS_ERR(data->vdd_reg))
0426         return PTR_ERR(data->vdd_reg);
0427
0428     err = regulator_enable(data->vdd_reg);
0429     if (err)
0430         return err;
0431
0432     if (pdata->use_vref) {
0433         data->vref_reg = devm_regulator_get(&client->dev, "vref");
0434         if (IS_ERR(data->vref_reg)) {
0435             err = PTR_ERR(data->vref_reg);
0436             goto err_disable_vdd_reg;
0437         }
0438
0439         err = regulator_enable(data->vref_reg);
0440         if (err)
0441             goto err_disable_vdd_reg;
0442     }
0443
0444     indio_dev->name = id->name;
0445     indio_dev->info = &mcp4725_info;
0446     indio_dev->channels = &mcp472x_channel[id->driver_data];
0447     indio_dev->num_channels = 1;
0448     indio_dev->modes = INDIO_DIRECT_MODE;
0449
0450     /* read current DAC value and settings */
0451     err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4);
0452
0453     if (err < 0) {
0454         dev_err(&client->dev, "failed to read DAC value");
0455         goto err_disable_vref_reg;
0456     }
0457     pd = (inbuf[0] >> 1) & 0x3;
0458     data->powerdown = pd > 0;
0459     data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
0460     data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
0461     if (data->id == MCP4726)
0462         ref = (inbuf[3] >> 3) & 0x3;
0463
0464     if (data->id == MCP4726 && ref != data->ref_mode) {
0465         dev_info(&client->dev,
0466             "voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
0467             data->ref_mode, ref, data->ref_mode);
0468         err = mcp4726_set_cfg(indio_dev);
0469         if (err < 0)
0470             goto err_disable_vref_reg;
0471     }
0472
0473     err = iio_device_register(indio_dev);
0474     if (err)
0475         goto err_disable_vref_reg;
0476
0477     return 0;
0478
0479 err_disable_vref_reg:
0480     if (data->vref_reg)
0481         regulator_disable(data->vref_reg);
0482
0483 err_disable_vdd_reg:
0484     regulator_disable(data->vdd_reg);
0485
0486     return err;
0487 }
0488
0489 static int mcp4725_remove(struct i2c_client *client)
0490 {
0491     struct iio_dev *indio_dev = i2c_get_clientdata(client);
0492     struct mcp4725_data *data = iio_priv(indio_dev);
0493
0494     iio_device_unregister(indio_dev);
0495
0496     if (data->vref_reg)
0497         regulator_disable(data->vref_reg);
0498     regulator_disable(data->vdd_reg);
0499
0500     return 0;
0501 }
0502
0503 static const struct i2c_device_id mcp4725_id[] = {
0504     { "mcp4725", MCP4725 },
0505     { "mcp4726", MCP4726 },
0506     { }
0507 };
0508 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
0509
0510 static const struct of_device_id mcp4725_of_match[] = {
0511     {
0512         .compatible = "microchip,mcp4725",
0513         .data = (void *)MCP4725
0514     },
0515     {
0516         .compatible = "microchip,mcp4726",
0517         .data = (void *)MCP4726
0518     },
0519     { }
0520 };
0521 MODULE_DEVICE_TABLE(of, mcp4725_of_match);
0522
0523 static struct i2c_driver mcp4725_driver = {
0524     .driver = {
0525         .name   = MCP4725_DRV_NAME,
0526         .of_match_table = mcp4725_of_match,
0527         .pm = pm_sleep_ptr(&mcp4725_pm_ops),
0528     },
0529     .probe      = mcp4725_probe,
0530     .remove     = mcp4725_remove,
0531     .id_table   = mcp4725_id,
0532 };
0533 module_i2c_driver(mcp4725_driver);
0534
0535 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
0536 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
0537 MODULE_LICENSE("GPL");