Re: [PATCH 1/4] iio: add store_eeprom to mcp4725 dac driver

[Jonathan Cameron <jic23@kernel.org>]

On 06/23/2013 10:30 PM, Peter Meerwald wrote:
> Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Applied to the togreg branch of iio.git
> ---
>  drivers/iio/dac/mcp4725.c | 64 +++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 62 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c
> index a612ec7..cb9db90 100644
> --- a/drivers/iio/dac/mcp4725.c
> +++ b/drivers/iio/dac/mcp4725.c
> @@ -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,
>  };
>  
>