Re: [PATCH 1/2] docs: dt: submitting-patches: Document sending DTS patches

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Krzysztof,

On Tue, Feb 25, 2025 at 07:48:21PM +0100, Krzysztof Kozlowski wrote:
> Document two rules already widely used and enforced by DT maintainers
> and SoC platform maintainers:
> 
> 1. DTS patches should be placed at the end of driver patchset to
>    indicate no dependencies of driver code on DTS.
> 
> 2. DTS patches should be applied via SoC platform maintainers, because
>    it is a driver-independent hardware description.  However some
>    driver maintainers are reluctant to pick up portions of patchsets and
>    prefer to take entire set at once.  For such cases, the DTS portion
>    should be split into separate patchset, so it will not end up in the
>    driver subsystem integration tree.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

This matches my understanding of the current (and best) practices, so

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  .../bindings/submitting-patches.rst           | 19 +++++++++++++++++--
>  1 file changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/submitting-patches.rst b/Documentation/devicetree/bindings/submitting-patches.rst
> index a64f21a5f299..f3e23e69a638 100644
> --- a/Documentation/devicetree/bindings/submitting-patches.rst
> +++ b/Documentation/devicetree/bindings/submitting-patches.rst
> @@ -54,11 +54,22 @@ I. For patch submitters
>       followed as of commit bff5da4335256513497cc8c79f9a9d1665e09864
>       ("checkpatch: add DT compatible string documentation checks"). ]
>  
> -  7) If a documented compatible string is not yet matched by the
> +  7) DTS is treated in general as driver-independent hardware description, thus
> +     any DTS patches, regardless whether using existing or new bindings, should
> +     be placed at the end of patchset to indicate no dependency of drivers on
> +     the DTS.  DTS will be anyway applied through separate tree or branch, so
> +     different order would indicate the serie is non-bisectable.
> +
> +     If a driver subsystem maintainer prefers to apply entire set, instead of
> +     their relevant portion of patchset, please split the DTS patches into
> +     separate patchset with a reference in changelog or cover letter to the
> +     bindings submission on the mailing list.
> +
> +  8) If a documented compatible string is not yet matched by the
>       driver, the documentation should also include a compatible
>       string that is matched by the driver.
>  
> -  8) Bindings are actively used by multiple projects other than the Linux
> +  9) Bindings are actively used by multiple projects other than the Linux
>       Kernel, extra care and consideration may need to be taken when making changes
>       to existing bindings.
>  
> @@ -79,6 +90,10 @@ II. For kernel maintainers
>    3) For a series going though multiple trees, the binding patch should be
>       kept with the driver using the binding.
>  
> +  4) The DTS files should however never be applied via driver subsystem tree,
> +     but always via platform SoC trees on dedicated branches (see also
> +     Documentation/process/maintainer-soc.rst).
> +
>  III. Notes
>  ==========
>  
> -- 
> 2.43.0
> 
> 

-- 
Regards,

Laurent Pinchart