Re: [PATCH v2 3/3] Documentation: ABI: adl8113: add documentation

[Jonathan Cameron <jic23@kernel.org>]

On Sat, 8 Nov 2025 17:43:54 +0000
Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:

> Add ABI documentation for the ADL8113 Low Noise Amplifier,
> covering the 4 pin-selectable operating modes.
> 
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>

I'm still reluctant to have a mode parameter because they are close
to unusable because they always indicate something highly device
specific that no generic userspace can make use of.

My hang up continues to be that the first two are normal _scale
controls, but the 2nd two are saying use this path for the signal
with analog components in it, but providing no info on what that
means wrt to what is measured.

If we do go ahead with this, then it needs a more specific name
to avoid trampling on the namespace as "mode" would.
> ---
> 
> Changes in v2:
> - Enhance external_bypass_a mode description: clarify signal routing from RFIN to OUT_A and from IN_A to RFOUT
> - Enhance external_bypass_b mode description: clarify signal routing from RFIN to OUT_B and from IN_B to RFOUT
>  .../testing/sysfs-bus-iio-amplifiers-adl8113  | 32 +++++++++++++++++++
>  1 file changed, 32 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-amplifiers-adl8113
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-amplifiers-adl8113 b/Documentation/ABI/testing/sysfs-bus-iio-amplifiers-adl8113
> new file mode 100644
> index 000000000000..6e3994283a45
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-amplifiers-adl8113
> @@ -0,0 +1,32 @@
> +What:		/sys/bus/iio/devices/iio:deviceX/mode
> +Date:		January 2025
> +KernelVersion:	6.14
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		This attribute allows the user to set the operation mode of the
> +		ADL8113 Low Noise Amplifier. The available modes control signal
> +		routing through different paths within the device.
> +
> +		The supported modes are:
> +
> +		* internal_amplifier - Signal passes through the internal low
> +		  noise amplifier (VA=0, VB=0). Provides 14dB gain.
> +
> +		* internal_bypass - Signal bypasses through internal bypass path
> +		  (VA=1, VB=1). Provides 0dB gain.
> +
> +		* external_bypass_a - Signal routes from RFIN to OUT_A and from IN_A to RFOUT
> +		  (VA=0, VB=1). Provides 0dB gain.
> +
> +		* external_bypass_b - Signal routes from RFIN to OUT_B and from IN_B to RFOUT
> +		  (VA=1, VB=0). Provides 0dB gain.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/mode_available
> +Date:		January 2025
> +KernelVersion:	6.14
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Reading this attribute returns a space-separated list of all
> +		available operation modes for the ADL8113 device. The modes
> +		control the signal path and determine whether the signal passes
> +		through the internal amplifier or various bypass paths.