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/*
* mcp4725.c - Support for Microchip MCP4725
*
* 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)
*
* writing the DAC value to EEPROM is not supported
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/dac/mcp4725.h>
#define MCP4725_DRV_NAME "mcp4725"
struct mcp4725_data {
struct i2c_client *client;
u16 vref_mv;
u16 dac_value;
};
#ifdef CONFIG_PM_SLEEP
static int mcp4725_suspend(struct device *dev)
{
u8 outbuf[2];
outbuf[0] = 0x3 << 4; /* power-down bits, 500 kOhm resistor */
outbuf[1] = 0;
return i2c_master_send(to_i2c_client(dev), outbuf, 2);
}
static int mcp4725_resume(struct device *dev)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct mcp4725_data *data = iio_priv(indio_dev);
u8 outbuf[2];
/* restore previous DAC value */
outbuf[0] = (data->dac_value >> 8) & 0xf;
outbuf[1] = data->dac_value & 0xff;
return i2c_master_send(to_i2c_client(dev), outbuf, 2);
}
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 const struct iio_chan_spec mcp4725_channel = {
.type = IIO_VOLTAGE,
.indexed = 1,
.output = 1,
.channel = 0,
.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
IIO_CHAN_INFO_SCALE_SHARED_BIT,
.scan_type = IIO_ST('u', 12, 16, 0),
};
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 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);
unsigned long scale_uv;
switch (mask) {
case IIO_CHAN_INFO_RAW:
*val = data->dac_value;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
scale_uv = (data->vref_mv * 1000) >> 12;
*val = scale_uv / 1000000;
*val2 = scale_uv % 1000000;
return IIO_VAL_INT_PLUS_MICRO;
}
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,
.driver_module = THIS_MODULE,
};
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 *platform_data = client->dev.platform_data;
u8 inbuf[3];
int err;
if (!platform_data || !platform_data->vref_mv) {
dev_err(&client->dev, "invalid platform data");
err = -EINVAL;
goto exit;
}
indio_dev = iio_device_alloc(sizeof(*data));
if (indio_dev == NULL) {
err = -ENOMEM;
goto exit;
}
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
indio_dev->dev.parent = &client->dev;
indio_dev->info = &mcp4725_info;
indio_dev->channels = &mcp4725_channel;
indio_dev->num_channels = 1;
indio_dev->modes = INDIO_DIRECT_MODE;
data->vref_mv = platform_data->vref_mv;
/* read current DAC value */
err = i2c_master_recv(client, inbuf, 3);
if (err < 0) {
dev_err(&client->dev, "failed to read DAC value");
goto exit_free_device;
}
data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
err = iio_device_register(indio_dev);
if (err)
goto exit_free_device;
dev_info(&client->dev, "MCP4725 DAC registered\n");
return 0;
exit_free_device:
iio_device_free(indio_dev);
exit:
return err;
}
static int mcp4725_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
iio_device_unregister(indio_dev);
iio_device_free(indio_dev);
return 0;
}
static const struct i2c_device_id mcp4725_id[] = {
{ "mcp4725", 0 },
{ }
};
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 12-bit DAC");
MODULE_LICENSE("GPL");
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