Re: [PATCH 2/3] media: docs: v4l2-subdev: move "Subdev registration" to a subsection

From: Jacopo Mondi
Date: Tue Sep 15 2020 - 20:33:48 EST


Hi Luca,

On Fri, Sep 04, 2020 at 11:51:40PM +0200, Luca Ceresoli wrote:
> The subdev registration topic is pretty lengthy, and takes more than
> half of the "V4L2 sub-devices" section. Help readers in finding their
> way through the document by dedicating a subsection to
> "Subdev registration".
>
> Each of the two registration methods takes many paragraphs, but since
> adding a subsubsection would be overkill, just emphasize them in bold.

I see bold being used mostly for C symbols names, I don't know if
that's a kind of convention or not.

I would not mind a subsection to be honest...
I think the patch is good and I'll provide a tag, maybe others can
provide opinions too!

Reviewed-by: Jacopo Mondi <jacopo@xxxxxxxxxx>

Thanks
j

>
> Signed-off-by: Luca Ceresoli <luca@xxxxxxxxxxxxxxxx>
> ---
> Documentation/driver-api/media/v4l2-subdev.rst | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/driver-api/media/v4l2-subdev.rst b/Documentation/driver-api/media/v4l2-subdev.rst
> index 9a7dddd97f5a..fb66163deb38 100644
> --- a/Documentation/driver-api/media/v4l2-subdev.rst
> +++ b/Documentation/driver-api/media/v4l2-subdev.rst
> @@ -138,6 +138,9 @@ ensures that width, height and the media bus pixel code are equal on both source
> and sink of the link. Subdev drivers are also free to use this function to
> perform the checks mentioned above in addition to their own checks.
>
> +Subdev registration
> +~~~~~~~~~~~~~~~~~~~
> +
> There are currently two ways to register subdevices with the V4L2 core. The
> first (traditional) possibility is to have subdevices registered by bridge
> drivers. This can be done when the bridge driver has the complete information
> @@ -157,7 +160,7 @@ below.
> Using one or the other registration method only affects the probing process, the
> run-time bridge-subdevice interaction is in both cases the same.
>
> -In the synchronous case a device (bridge) driver needs to register the
> +In the **synchronous** case a device (bridge) driver needs to register the
> :c:type:`v4l2_subdev` with the v4l2_device:
>
> :c:func:`v4l2_device_register_subdev <v4l2_device_register_subdev>`
> @@ -238,9 +241,9 @@ contain several subdevs that use an I2C bus, but also a subdev that is
> controlled through GPIO pins. This distinction is only relevant when setting
> up the device, but once the subdev is registered it is completely transparent.
>
> -In the asynchronous case subdevice probing can be invoked independently of the
> -bridge driver availability. The subdevice driver then has to verify whether all
> -the requirements for a successful probing are satisfied. This can include a
> +In the **asynchronous** case subdevice probing can be invoked independently of
> +the bridge driver availability. The subdevice driver then has to verify whether
> +all the requirements for a successful probing are satisfied. This can include a
> check for a master clock availability. If any of the conditions aren't satisfied
> the driver might decide to return ``-EPROBE_DEFER`` to request further reprobing
> attempts. Once all conditions are met the subdevice shall be registered using
> --
> 2.28.0
>