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linux-sg2042/drivers/iio/dac/mcp4725.c

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/*
* mcp4725.c - Support for Microchip MCP4725/6
*
* Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
*
* Based on max517 by Roland Stigge <stigge@antcom.de>
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*
* 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/of.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 mcp4725_suspend(struct device *dev)
{
struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
to_i2c_client(dev)));
u8 outbuf[2];
outbuf[0] = (data->powerdown_mode + 1) << 4;
outbuf[1] = 0;
data->powerdown = true;
return i2c_master_send(data->client, outbuf, 2);
}
static int mcp4725_resume(struct device *dev)
{
struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
to_i2c_client(dev)));
u8 outbuf[2];
/* restore previous DAC value */
outbuf[0] = (data->dac_value >> 8) & 0xf;
outbuf[1] = data->dac_value & 0xff;
data->powerdown = false;
return i2c_master_send(data->client, outbuf, 2);
}
#ifdef CONFIG_PM_SLEEP
static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
#define MCP4725_PM_OPS (&mcp4725_pm_ops)
#else
#define MCP4725_PM_OPS NULL
#endif
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[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 {
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,
.driver_module = THIS_MODULE,
};
#ifdef CONFIG_OF
static int mcp4725_probe_dt(struct device *dev,
struct mcp4725_platform_data *pdata)
{
struct device_node *np = dev->of_node;
if (!np)
return -ENODEV;
/* check if is the vref-supply defined */
pdata->use_vref = of_property_read_bool(np, "vref-supply");
pdata->vref_buffered =
of_property_read_bool(np, "microchip,vref-buffered");
return 0;
}
#else
static int mcp4725_probe_dt(struct device *dev,
struct mcp4725_platform_data *platform_data)
{
return -ENODEV;
}
#endif
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;
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->dev.parent = &client->dev;
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 ? true : false;
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 struct i2c_driver mcp4725_driver = {
.driver = {
.name = MCP4725_DRV_NAME,
.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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