Re: [PATCH 3/4] iio: dac: adi-axi-dac: add data source get

[Nuno Sá]

On Fri, 2025-03-21 at 21:28 +0100, Angelo Dureghello wrote:
> From: Angelo Dureghello <adureghello@xxxxxxxxxxxx>
> 
> Add data source getter.
> 
> Signed-off-by: Angelo Dureghello <adureghello@xxxxxxxxxxxx>
> ---
>  drivers/iio/dac/adi-axi-dac.c | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/drivers/iio/dac/adi-axi-dac.c b/drivers/iio/dac/adi-axi-dac.c
> index
> 892d770aec69c4259de777058801c9ab33c79923..a6abd828ebdb34800cc08a2151e52a9acda9eba1
> 100644
> --- a/drivers/iio/dac/adi-axi-dac.c
> +++ b/drivers/iio/dac/adi-axi-dac.c
> @@ -514,6 +514,32 @@ static int axi_dac_data_source_set(struct iio_backend *back,
> unsigned int chan,
>  	}
>  }
>  
> +static int axi_dac_data_source_get(struct iio_backend *back, unsigned int chan,
> +				   enum iio_backend_data_source *data)
> +{
> +	struct axi_dac_state *st = iio_backend_get_priv(back);
> +	int ret;
> +	u32 val;
> +
> +	ret = regmap_read(st->regmap, AXI_DAC_CHAN_CNTRL_7_REG(chan), &val);
> +	if (ret)
> +		return ret;

Is chan something that we can validate? Do we reliable know max number of channels?

> +
> +	switch (val) {
> +	case AXI_DAC_DATA_INTERNAL_TONE:
> +		*data = IIO_BACKEND_INTERNAL_CONTINUOUS_WAVE;
> +		return 0;
> +	case AXI_DAC_DATA_DMA:
> +		*data = IIO_BACKEND_EXTERNAL;
> +		return 0;
> +	case AXI_DAC_DATA_INTERNAL_RAMP_16BIT:
> +		*data = IIO_BACKEND_INTERNAL_RAMP_16BIT;
> +		return 0;
> +	default:
> +		return -EINVAL;

More of a nitpick comment but I would some other error code. This is not really an
"Invalid argument" situation. Maybe -EIO as the HW is giving something unexpected? or
ENOTSUPP (likely not exactly like this)...

- Nuno Sá

>  	.ddr_disable = axi_dac_ddr_disable,
>  	.data_stream_enable = axi_dac_data_stream_enable,
>