Re: [PATCH 2/4] iio: add powerdown to mcp4725 dac drive

[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 iio.git
> ---
>  drivers/iio/dac/mcp4725.c | 87 +++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 85 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c
> index cb9db90..f569738 100644
> --- a/drivers/iio/dac/mcp4725.c
> +++ b/drivers/iio/dac/mcp4725.c
> @@ -31,15 +31,19 @@ struct mcp4725_data {
>  	struct i2c_client *client;
>  	u16 vref_mv;
>  	u16 dac_value;
> +	bool powerdown;
> +	unsigned powerdown_mode;
>  };
>  
> -#ifdef CONFIG_PM_SLEEP
>  static int mcp4725_suspend(struct device *dev)
>  {
> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> +	struct mcp4725_data *data = iio_priv(indio_dev);
>  	u8 outbuf[2];
>  
> -	outbuf[0] = 0x3 << 4; /* power-down bits, 500 kOhm resistor */
> +	outbuf[0] = (data->powerdown_mode + 1) << 4;
>  	outbuf[1] = 0;
> +	data->powerdown = true;
>  
>  	return i2c_master_send(to_i2c_client(dev), outbuf, 2);
>  }
> @@ -53,10 +57,12 @@ static int mcp4725_resume(struct device *dev)
>  	/* restore previous DAC value */
>  	outbuf[0] = (data->dac_value >> 8) & 0xf;
>  	outbuf[1] = data->dac_value & 0xff;
> +	data->powerdown = false;
>  
>  	return i2c_master_send(to_i2c_client(dev), 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
> @@ -123,6 +129,78 @@ 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 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;
> +}
> +
> +static const struct iio_enum mcp4725_powerdown_mode_enum = {
> +	.items = mcp4725_powerdown_modes,
> +	.num_items = ARRAY_SIZE(mcp4725_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,
> +	},
> +	IIO_ENUM("powerdown_mode", false, &mcp4725_powerdown_mode_enum),
> +	IIO_ENUM_AVAILABLE("powerdown_mode", &mcp4725_powerdown_mode_enum),
> +	{ },
> +};
> +
>  static const struct iio_chan_spec mcp4725_channel = {
>  	.type		= IIO_VOLTAGE,
>  	.indexed	= 1,
> @@ -131,6 +209,7 @@ static const struct iio_chan_spec mcp4725_channel = {
>  	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
>  	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
>  	.scan_type	= IIO_ST('u', 12, 16, 0),
> +	.ext_info	= mcp4725_ext_info,
>  };
>  
>  static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
> @@ -208,6 +287,7 @@ static int mcp4725_probe(struct i2c_client *client,
>  	struct iio_dev *indio_dev;
>  	struct mcp4725_platform_data *platform_data = client->dev.platform_data;
>  	u8 inbuf[3];
> +	u8 pd;
>  	int err;
>  
>  	if (!platform_data || !platform_data->vref_mv) {
> @@ -239,6 +319,9 @@ static int mcp4725_probe(struct i2c_client *client,
>  		dev_err(&client->dev, "failed to read DAC value");
>  		goto exit_free_device;
>  	}
> +	pd = (inbuf[0] >> 1) & 0x3;
> +	data->powerdown = pd > 0 ? true : false;
> +	data->powerdown_mode = pd ? pd-1 : 2; /* 500kohm_to_gnd */
>  	data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
>  
>  	err = iio_device_register(indio_dev);
>