Re: [PATCH v3 2/3] Documentation: ABI: added filter mode doc in sysfs-bus-iio

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 19 Jun 2024 15:22:43 +0300
Ramona Alexandra Nechita <ramona.nechita@analog.com> wrote:

> The filter mode / filter type property is used for ad4130
> and ad7779 drivers, therefore the ABI doc file for ad4130
> was removed, merging both of them in the sysfs-bus-iio
> 
> Signed-off-by: Ramona Alexandra Nechita <ramona.nechita@analog.com>
> ---
>  Documentation/ABI/testing/sysfs-bus-iio       |  7 +++
>  .../ABI/testing/sysfs-bus-iio-adc-ad4130      | 46 -------------------
>  2 files changed, 7 insertions(+), 46 deletions(-)
>  delete mode 100644 Documentation/ABI/testing/sysfs-bus-iio-adc-ad4130
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> index 2e6d5ebfd3c7..c808ec9c4a81 100644
> --- a/Documentation/ABI/testing/sysfs-bus-iio
> +++ b/Documentation/ABI/testing/sysfs-bus-iio
> @@ -2225,6 +2225,13 @@ Description:
>  		An example format is 16-bytes, 2-digits-per-byte, HEX-string
>  		representing the sensor unique ID number.
>  
> +What:		/sys/bus/iio/devices/iio:deviceX/filter_type_available
> +What:		/sys/bus/iio/devices/iio:deviceX/in_voltage-voltage_filter_mode_available
> +KernelVersion:	6.1
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Reading returns a list with the possible filter modes.
Even though it is not generalized an a given device might not provide each option, we still
need to let those writing userspace software know what they might get.
So Include the options, but skip the frequency specific details etc.

For things like the pf ones, just say + device specific post filter X

If the details are necessary we do allow a device specific entry in the main
docs.  I think there are a few existing ones though not sure they've
made it to the top level doc rather than one of the device type specific ones.



> +
>  What:		/sys/.../events/in_proximity_thresh_either_runningperiod
>  KernelVersion:	6.6
>  Contact:	linux-iio@vger.kernel.org
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-adc-ad4130 b/Documentation/ABI/testing/sysfs-bus-iio-adc-ad4130
> deleted file mode 100644
> index f24ed6687e90..000000000000
> --- a/Documentation/ABI/testing/sysfs-bus-iio-adc-ad4130
> +++ /dev/null
> @@ -1,46 +0,0 @@
> -What:		/sys/bus/iio/devices/iio:deviceX/in_voltage-voltage_filter_mode_available
> -KernelVersion:  6.2
> -Contact:	linux-iio@vger.kernel.org
> -Description:
> -		Reading returns a list with the possible filter modes.
> -
> -		  * "sinc4"       - Sinc 4. Excellent noise performance. Long
> -                    1st conversion time. No natural 50/60Hz rejection.
> -
> -		  * "sinc4+sinc1" - Sinc4 + averaging by 8. Low 1st conversion
> -		    time.
> -
> -		  * "sinc3"	      - Sinc3. Moderate 1st conversion time.
> -		    Good noise performance.
> -
> -		  * "sinc3+rej60" - Sinc3 + 60Hz rejection. At a sampling
> -		    frequency of 50Hz, achieves simultaneous 50Hz and 60Hz
> -		    rejection.
> -
> -		  * "sinc3+sinc1" - Sinc3 + averaging by 8. Low 1st conversion
> -		    time. Best used with a sampling frequency of at least
> -		    216.19Hz.
> -
> -		  * "sinc3+pf1"   - Sinc3 + Post Filter 1. 53dB rejection @
> -		    50Hz, 58dB rejection @ 60Hz.
> -
> -		  * "sinc3+pf2"   - Sinc3 + Post Filter 2. 70dB rejection @
> -		    50Hz, 70dB rejection @ 60Hz.
> -
> -		  * "sinc3+pf3"   - Sinc3 + Post Filter 3. 99dB rejection @
> -		    50Hz, 103dB rejection @ 60Hz.
> -
> -		  * "sinc3+pf4"   - Sinc3 + Post Filter 4. 103dB rejection @
> -		    50Hz, 109dB rejection @ 60Hz.
> -
> -What:		/sys/bus/iio/devices/iio:deviceX/in_voltageY-voltageZ_filter_mode
> -KernelVersion:  6.2
> -Contact:	linux-iio@vger.kernel.org
> -Description:
> -		Set the filter mode of the differential channel. When the filter
> -		mode changes, the in_voltageY-voltageZ_sampling_frequency and
> -		in_voltageY-voltageZ_sampling_frequency_available attributes
> -		might also change to accommodate the new filter mode.
> -		If the current sampling frequency is out of range for the new
> -		filter mode, the sampling frequency will be changed to the
> -		closest valid one.