diff options
Diffstat (limited to 'drivers/iio/dac/mcp4725.c')
| -rw-r--r-- | drivers/iio/dac/mcp4725.c | 548 |
1 files changed, 548 insertions, 0 deletions
diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c new file mode 100644 index 000000000..0c0e726ae --- /dev/null +++ b/drivers/iio/dac/mcp4725.c @@ -0,0 +1,548 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * mcp4725.c - Support for Microchip MCP4725/6 + * + * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net> + * + * Based on max517 by Roland Stigge <stigge@antcom.de> + * + * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC) + * (7-bit I2C slave address 0x60, the three LSBs can be configured in + * hardware) + */ + +#include <linux/module.h> +#include <linux/i2c.h> +#include <linux/err.h> +#include <linux/delay.h> +#include <linux/regulator/consumer.h> +#include <linux/mod_devicetable.h> +#include <linux/property.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +#include <linux/iio/dac/mcp4725.h> + +#define MCP4725_DRV_NAME "mcp4725" + +#define MCP472X_REF_VDD 0x00 +#define MCP472X_REF_VREF_UNBUFFERED 0x02 +#define MCP472X_REF_VREF_BUFFERED 0x03 + +struct mcp4725_data { + struct i2c_client *client; + int id; + unsigned ref_mode; + bool vref_buffered; + u16 dac_value; + bool powerdown; + unsigned powerdown_mode; + struct regulator *vdd_reg; + struct regulator *vref_reg; +}; + +static int __maybe_unused mcp4725_suspend(struct device *dev) +{ + struct mcp4725_data *data = iio_priv(i2c_get_clientdata( + to_i2c_client(dev))); + u8 outbuf[2]; + int ret; + + outbuf[0] = (data->powerdown_mode + 1) << 4; + outbuf[1] = 0; + data->powerdown = true; + + ret = i2c_master_send(data->client, outbuf, 2); + if (ret < 0) + return ret; + else if (ret != 2) + return -EIO; + return 0; +} + +static int __maybe_unused mcp4725_resume(struct device *dev) +{ + struct mcp4725_data *data = iio_priv(i2c_get_clientdata( + to_i2c_client(dev))); + u8 outbuf[2]; + int ret; + + /* restore previous DAC value */ + outbuf[0] = (data->dac_value >> 8) & 0xf; + outbuf[1] = data->dac_value & 0xff; + data->powerdown = false; + + ret = i2c_master_send(data->client, outbuf, 2); + if (ret < 0) + return ret; + else if (ret != 2) + return -EIO; + return 0; +} +static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume); + +static ssize_t mcp4725_store_eeprom(struct device *dev, + struct device_attribute *attr, const char *buf, size_t len) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct mcp4725_data *data = iio_priv(indio_dev); + int tries = 20; + u8 inoutbuf[3]; + bool state; + int ret; + + ret = strtobool(buf, &state); + if (ret < 0) + return ret; + + if (!state) + return 0; + + inoutbuf[0] = 0x60; /* write EEPROM */ + inoutbuf[0] |= data->ref_mode << 3; + inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0; + inoutbuf[1] = data->dac_value >> 4; + inoutbuf[2] = (data->dac_value & 0xf) << 4; + + ret = i2c_master_send(data->client, inoutbuf, 3); + if (ret < 0) + return ret; + else if (ret != 3) + return -EIO; + + /* wait for write complete, takes up to 50ms */ + while (tries--) { + msleep(20); + ret = i2c_master_recv(data->client, inoutbuf, 3); + if (ret < 0) + return ret; + else if (ret != 3) + return -EIO; + + if (inoutbuf[0] & 0x80) + break; + } + + if (tries < 0) { + dev_err(&data->client->dev, + "mcp4725_store_eeprom() failed, incomplete\n"); + return -EIO; + } + + return len; +} + +static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0); + +static struct attribute *mcp4725_attributes[] = { + &iio_dev_attr_store_eeprom.dev_attr.attr, + NULL, +}; + +static const struct attribute_group mcp4725_attribute_group = { + .attrs = mcp4725_attributes, +}; + +static const char * const mcp4725_powerdown_modes[] = { + "1kohm_to_gnd", + "100kohm_to_gnd", + "500kohm_to_gnd" +}; + +static const char * const mcp4726_powerdown_modes[] = { + "1kohm_to_gnd", + "125kohm_to_gnd", + "640kohm_to_gnd" +}; + +static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + + return data->powerdown_mode; +} + +static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, unsigned mode) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + + data->powerdown_mode = mode; + + return 0; +} + +static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev, + uintptr_t private, const struct iio_chan_spec *chan, char *buf) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + + return sprintf(buf, "%d\n", data->powerdown); +} + +static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev, + uintptr_t private, const struct iio_chan_spec *chan, + const char *buf, size_t len) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + bool state; + int ret; + + ret = strtobool(buf, &state); + if (ret) + return ret; + + if (state) + ret = mcp4725_suspend(&data->client->dev); + else + ret = mcp4725_resume(&data->client->dev); + if (ret < 0) + return ret; + + return len; +} + +enum chip_id { + MCP4725, + MCP4726, +}; + +static const struct iio_enum mcp472x_powerdown_mode_enum[] = { + [MCP4725] = { + .items = mcp4725_powerdown_modes, + .num_items = ARRAY_SIZE(mcp4725_powerdown_modes), + .get = mcp4725_get_powerdown_mode, + .set = mcp4725_set_powerdown_mode, + }, + [MCP4726] = { + .items = mcp4726_powerdown_modes, + .num_items = ARRAY_SIZE(mcp4726_powerdown_modes), + .get = mcp4725_get_powerdown_mode, + .set = mcp4725_set_powerdown_mode, + }, +}; + +static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = { + { + .name = "powerdown", + .read = mcp4725_read_powerdown, + .write = mcp4725_write_powerdown, + .shared = IIO_SEPARATE, + }, + IIO_ENUM("powerdown_mode", IIO_SEPARATE, + &mcp472x_powerdown_mode_enum[MCP4725]), + IIO_ENUM_AVAILABLE("powerdown_mode", + &mcp472x_powerdown_mode_enum[MCP4725]), + { }, +}; + +static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = { + { + .name = "powerdown", + .read = mcp4725_read_powerdown, + .write = mcp4725_write_powerdown, + .shared = IIO_SEPARATE, + }, + IIO_ENUM("powerdown_mode", IIO_SEPARATE, + &mcp472x_powerdown_mode_enum[MCP4726]), + IIO_ENUM_AVAILABLE("powerdown_mode", + &mcp472x_powerdown_mode_enum[MCP4726]), + { }, +}; + +static const struct iio_chan_spec mcp472x_channel[] = { + [MCP4725] = { + .type = IIO_VOLTAGE, + .indexed = 1, + .output = 1, + .channel = 0, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), + .ext_info = mcp4725_ext_info, + }, + [MCP4726] = { + .type = IIO_VOLTAGE, + .indexed = 1, + .output = 1, + .channel = 0, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), + .ext_info = mcp4726_ext_info, + }, +}; + +static int mcp4725_set_value(struct iio_dev *indio_dev, int val) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + u8 outbuf[2]; + int ret; + + if (val >= (1 << 12) || val < 0) + return -EINVAL; + + outbuf[0] = (val >> 8) & 0xf; + outbuf[1] = val & 0xff; + + ret = i2c_master_send(data->client, outbuf, 2); + if (ret < 0) + return ret; + else if (ret != 2) + return -EIO; + else + return 0; +} + +static int mcp4726_set_cfg(struct iio_dev *indio_dev) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + u8 outbuf[3]; + int ret; + + outbuf[0] = 0x40; + outbuf[0] |= data->ref_mode << 3; + if (data->powerdown) + outbuf[0] |= data->powerdown << 1; + outbuf[1] = data->dac_value >> 4; + outbuf[2] = (data->dac_value & 0xf) << 4; + + ret = i2c_master_send(data->client, outbuf, 3); + if (ret < 0) + return ret; + else if (ret != 3) + return -EIO; + else + return 0; +} + +static int mcp4725_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + *val = data->dac_value; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + if (data->ref_mode == MCP472X_REF_VDD) + ret = regulator_get_voltage(data->vdd_reg); + else + ret = regulator_get_voltage(data->vref_reg); + + if (ret < 0) + return ret; + + *val = ret / 1000; + *val2 = 12; + return IIO_VAL_FRACTIONAL_LOG2; + } + return -EINVAL; +} + +static int mcp4725_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = mcp4725_set_value(indio_dev, val); + data->dac_value = val; + break; + default: + ret = -EINVAL; + break; + } + + return ret; +} + +static const struct iio_info mcp4725_info = { + .read_raw = mcp4725_read_raw, + .write_raw = mcp4725_write_raw, + .attrs = &mcp4725_attribute_group, +}; + +static int mcp4725_probe_dt(struct device *dev, + struct mcp4725_platform_data *pdata) +{ + /* check if is the vref-supply defined */ + pdata->use_vref = device_property_read_bool(dev, "vref-supply"); + pdata->vref_buffered = + device_property_read_bool(dev, "microchip,vref-buffered"); + + return 0; +} + +static int mcp4725_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct mcp4725_data *data; + struct iio_dev *indio_dev; + struct mcp4725_platform_data *pdata, pdata_dt; + u8 inbuf[4]; + u8 pd; + u8 ref; + int err; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); + if (indio_dev == NULL) + return -ENOMEM; + data = iio_priv(indio_dev); + i2c_set_clientdata(client, indio_dev); + data->client = client; + if (dev_fwnode(&client->dev)) + data->id = (enum chip_id)device_get_match_data(&client->dev); + else + data->id = id->driver_data; + pdata = dev_get_platdata(&client->dev); + + if (!pdata) { + err = mcp4725_probe_dt(&client->dev, &pdata_dt); + if (err) { + dev_err(&client->dev, + "invalid platform or devicetree data"); + return err; + } + pdata = &pdata_dt; + } + + if (data->id == MCP4725 && pdata->use_vref) { + dev_err(&client->dev, + "external reference is unavailable on MCP4725"); + return -EINVAL; + } + + if (!pdata->use_vref && pdata->vref_buffered) { + dev_err(&client->dev, + "buffering is unavailable on the internal reference"); + return -EINVAL; + } + + if (!pdata->use_vref) + data->ref_mode = MCP472X_REF_VDD; + else + data->ref_mode = pdata->vref_buffered ? + MCP472X_REF_VREF_BUFFERED : + MCP472X_REF_VREF_UNBUFFERED; + + data->vdd_reg = devm_regulator_get(&client->dev, "vdd"); + if (IS_ERR(data->vdd_reg)) + return PTR_ERR(data->vdd_reg); + + err = regulator_enable(data->vdd_reg); + if (err) + return err; + + if (pdata->use_vref) { + data->vref_reg = devm_regulator_get(&client->dev, "vref"); + if (IS_ERR(data->vref_reg)) { + err = PTR_ERR(data->vref_reg); + goto err_disable_vdd_reg; + } + + err = regulator_enable(data->vref_reg); + if (err) + goto err_disable_vdd_reg; + } + + indio_dev->name = id->name; + indio_dev->info = &mcp4725_info; + indio_dev->channels = &mcp472x_channel[id->driver_data]; + indio_dev->num_channels = 1; + indio_dev->modes = INDIO_DIRECT_MODE; + + /* read current DAC value and settings */ + err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4); + + if (err < 0) { + dev_err(&client->dev, "failed to read DAC value"); + goto err_disable_vref_reg; + } + pd = (inbuf[0] >> 1) & 0x3; + data->powerdown = pd > 0; + data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */ + data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4); + if (data->id == MCP4726) + ref = (inbuf[3] >> 3) & 0x3; + + if (data->id == MCP4726 && ref != data->ref_mode) { + dev_info(&client->dev, + "voltage reference mode differs (conf: %u, eeprom: %u), setting %u", + data->ref_mode, ref, data->ref_mode); + err = mcp4726_set_cfg(indio_dev); + if (err < 0) + goto err_disable_vref_reg; + } + + err = iio_device_register(indio_dev); + if (err) + goto err_disable_vref_reg; + + return 0; + +err_disable_vref_reg: + if (data->vref_reg) + regulator_disable(data->vref_reg); + +err_disable_vdd_reg: + regulator_disable(data->vdd_reg); + + return err; +} + +static int mcp4725_remove(struct i2c_client *client) +{ + struct iio_dev *indio_dev = i2c_get_clientdata(client); + struct mcp4725_data *data = iio_priv(indio_dev); + + iio_device_unregister(indio_dev); + + if (data->vref_reg) + regulator_disable(data->vref_reg); + regulator_disable(data->vdd_reg); + + return 0; +} + +static const struct i2c_device_id mcp4725_id[] = { + { "mcp4725", MCP4725 }, + { "mcp4726", MCP4726 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, mcp4725_id); + +static const struct of_device_id mcp4725_of_match[] = { + { + .compatible = "microchip,mcp4725", + .data = (void *)MCP4725 + }, + { + .compatible = "microchip,mcp4726", + .data = (void *)MCP4726 + }, + { } +}; +MODULE_DEVICE_TABLE(of, mcp4725_of_match); + +static struct i2c_driver mcp4725_driver = { + .driver = { + .name = MCP4725_DRV_NAME, + .of_match_table = mcp4725_of_match, + .pm = &mcp4725_pm_ops, + }, + .probe = mcp4725_probe, + .remove = mcp4725_remove, + .id_table = mcp4725_id, +}; +module_i2c_driver(mcp4725_driver); + +MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>"); +MODULE_DESCRIPTION("MCP4725/6 12-bit DAC"); +MODULE_LICENSE("GPL"); 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