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iio: add store_eeprom to mcp4725 dac driver

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Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Peter Meerwald 2013-06-23 22:30:00 +01:00 committed by Jonathan Cameron
parent 341673f141
commit f17b77d6cf
1 changed files with 62 additions and 2 deletions
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64
drivers/iio/dac/mcp4725.c
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@ -12,14 +12,13 @@
* 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/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
@ -64,6 +63,66 @@ static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
#define MCP4725_PM_OPS NULL
#endif
static int 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[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 struct iio_chan_spec mcp4725_channel = {
.type = IIO_VOLTAGE,
.indexed = 1,
@ -138,6 +197,7 @@ static int mcp4725_write_raw(struct iio_dev *indio_dev,
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,
};