Re: [PATCH v2 1/5] iio: ABI: Generalize ABI documentation for DAC

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Thu, 23 May 2024 11:19:05 +0800
Kim Seer Paller <kimseer.paller@analog.com> wrote:

> Introduces a more generalized ABI documentation for DAC. Instead of
> having separate ABI files for each DAC, we now have a single ABI file
> that covers the common sysfs interface for all DAC.
> 
> Co-developed-by: Michael Hennerich <michael.hennerich@analog.com>
> Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
> Signed-off-by: Kim Seer Paller <kimseer.paller@analog.com>
> ---
>  Documentation/ABI/testing/sysfs-bus-iio-dac   | 61 +++++++++++++++++++
>  .../ABI/testing/sysfs-bus-iio-dac-ltc2688     | 31 ----------
>  MAINTAINERS                                   |  8 +++
>  3 files changed, 69 insertions(+), 31 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-dac
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dac b/Documentation/ABI/testing/sysfs-bus-iio-dac
> new file mode 100644
> index 000000000000..53d5213520c6
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-dac
> @@ -0,0 +1,61 @@
> +What:		/sys/bus/iio/devices/iio:deviceX/out_currentY_toggle_en
> +KernelVersion:	5.18
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Toggle enable. Write 1 to enable toggle or 0 to disable it. This is
> +		useful when one wants to change the DAC output codes. The way it should
> +		be done is:
> +
> +		- disable toggle operation;
> +		- change out_currentY_raw0 and out_currentY_raw1;

Generalize to [0...N] or something like that to allow more symbols.

> +		- enable toggle operation.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/out_currentY_raw0
> +What:		/sys/bus/iio/devices/iio:deviceX/out_currentY_raw1
> +KernelVersion:	5.18
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		It has the same meaning as out_currentY_raw. This attribute is
> +		specific to toggle enabled channels and refers to the DAC output
> +		code in INPUT_A (_raw0) and INPUT_B (_raw1). The same scale and offset
> +		as in out_currentY_raw applies.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/out_currentY_symbol
> +KernelVersion:	5.18
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Performs a SW toggle. This attribute is specific to toggle
> +		enabled channels and allows to toggle between out_currentY_raw0
> +		and out_currentY_raw1 through software. Writing 0 will select
> +		out_currentY_raw0 while 1 selects out_currentY_raw1.
Perhaps write this more generally.  The ABI handles more than 2 symbol values.

                Performs a SW switch to a predefined output symbol, allowing
		switching between current symbol A with output
		out_currentY_rawA and new symbol B with output
		out_currentY_rawB by writing integer value B.
 
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/out_voltageY_toggle_en
> +KernelVersion:	5.18
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Toggle enable. Write 1 to enable toggle or 0 to disable it. This is
> +		useful when one wants to change the DAC output codes. The way it should
> +		be done is:
> +
> +		- disable toggle operation;
> +		- change out_voltageY_raw0 and out_voltageY_raw1;
> +		- enable toggle operation.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/out_voltageY_raw0
> +What:		/sys/bus/iio/devices/iio:deviceX/out_voltageY_raw1
> +KernelVersion:	5.18
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		It has the same meaning as out_voltageY_raw. This attribute is
> +		specific to toggle enabled channels and refers to the DAC output
> +		code in INPUT_A (_raw0) and INPUT_B (_raw1). The same scale and offset
> +		as in out_voltageY_raw applies.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/out_voltageY_symbol
> +KernelVersion:	5.18
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Performs a SW toggle. This attribute is specific to toggle
> +		enabled channels and allows to toggle between out_voltageY_raw0
> +		and out_voltageY_raw1 through software. Writing 0 will select
> +		out_voltageY_raw0 while 1 selects out_voltageY_raw1.

> diff --git a/MAINTAINERS b/MAINTAINERS
> index 758c202ec712..b3be54c09159 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -12850,6 +12850,14 @@ S:	Maintained
>  F:	Documentation/devicetree/bindings/iio/dac/lltc,ltc1660.yaml
>  F:	drivers/iio/dac/ltc1660.c
>  
> +LTC2664 IIO DAC DRIVER
> +M:	Michael Hennerich <michael.hennerich@analog.com>
> +M:	Kim Seer Paller <kimseer.paller@analog.com>
> +L:	linux-iio@vger.kernel.org
> +S:	Supported
> +W:	https://ez.analog.com/linux-software-drivers
> +F:	Documentation/ABI/testing/sysfs-bus-iio-dac

As it's a general doc, doesn't really belong in a driver specific entry.
So far we haven't listed these generic docs as having specific maintainers
and people have to rely on history to figure out who to cc.

> +
>  LTC2688 IIO DAC DRIVER
>  M:	Nuno Sá <nuno.sa@analog.com>
>  L:	linux-iio@vger.kernel.org