Re: [PATCH v2 9/9] iio: ABI: add DAC sysfs synchronous_mode parameter

[David Lechner]

On 9/5/24 10:17 AM, Angelo Dureghello wrote:
> From: Angelo Dureghello <adureghello@xxxxxxxxxxxx>
> 
> Some DACs as ad3552r need a synchronous mode setting, adding
> this parameter for ad3552r and for future use on other DACs,
> if needed.
> 
> Signed-off-by: Angelo Dureghello <adureghello@xxxxxxxxxxxx>
> ---
>  Documentation/ABI/testing/sysfs-bus-iio-dac | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dac b/Documentation/ABI/testing/sysfs-bus-iio-dac
> index 810eaac5533c..2f4960c79385 100644
> --- a/Documentation/ABI/testing/sysfs-bus-iio-dac
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-dac
> @@ -59,3 +59,19 @@ Description:
>  		multiple predefined symbols. Each symbol corresponds to a different
>  		output, denoted as out_voltageY_rawN, where N is the integer value
>  		of the symbol. Writing an integer value N will select out_voltageY_rawN.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/out_voltage_synchronous_mode
> +KernelVersion:	6.13
> +Contact:	linux-iio@xxxxxxxxxxxxxxx
> +Description:
> +		Arm or disarm a wait-for-synchronization flag. Arming this flag
> +		means the DAC will wait for a synchronizatiopn signal on a
> +		specific internal or external wired connection. I.e., there are
> +		cases where multiple DACs IP are built in the same chip or fpga
> +		design, and they need to start the data stream synchronized.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/out_voltage_synchronous_mode_available
> +KernelVersion:	6.13
> +Contact:	linux-iio@xxxxxxxxxxxxxxx
> +Description:
> +		List of available values for synchronous_mode.
> 

Since this depends on how things are wired, it seems like this should be
something specified in the devicetree, not through sysfs attributes.