Re: [PATCH 06/26] drm/bridge: add devm_drm_of_find_bridge

From: "Luca Ceresoli" <luca.ceresoli@bootlin.com>
To: "Maxime Ripard" <mripard@kernel.org>
Cc: "Andrzej Hajda" <andrzej.hajda@intel.com>,
	"Neil Armstrong" <neil.armstrong@linaro.org>,
	"Robert Foss" <rfoss@kernel.org>,
	"Laurent Pinchart" <Laurent.pinchart@ideasonboard.com>,
	"Jonas Karlman" <jonas@kwiboo.se>,
	"Jernej Skrabec" <jernej.skrabec@gmail.com>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"David Airlie" <airlied@gmail.com>,
	"Simona Vetter" <simona@ffwll.ch>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Alexey Brodkin" <abrodkin@synopsys.com>,
	"Phong LE" <ple@baylibre.com>, "Liu Ying" <victor.liu@nxp.com>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"Sascha Hauer" <s.hauer@pengutronix.de>,
	"Pengutronix Kernel Team" <kernel@pengutronix.de>,
	"Fabio Estevam" <festevam@gmail.com>,
	"Adrien Grassein" <adrien.grassein@gmail.com>,
	"Laurent Pinchart" <laurent.pinchart+renesas@ideasonboard.com>,
	"Tomi Valkeinen" <tomi.valkeinen+renesas@ideasonboard.com>,
	"Kieran Bingham" <kieran.bingham+renesas@ideasonboard.com>,
	"Geert Uytterhoeven" <geert+renesas@glider.be>,
	"Magnus Damm" <magnus.damm@gmail.com>,
	"Kevin Hilman" <khilman@baylibre.com>,
	"Jerome Brunet" <jbrunet@baylibre.com>,
	"Martin Blumenstingl" <martin.blumenstingl@googlemail.com>,
	"Chun-Kuang Hu" <chunkuang.hu@kernel.org>,
	"Philipp Zabel" <p.zabel@pengutronix.de>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"AngeloGioacchino Del Regno"
	<angelogioacchino.delregno@collabora.com>,
	"Anitha Chrisanthus" <anitha.chrisanthus@intel.com>,
	"Edmund Dea" <edmund.j.dea@intel.com>,
	"Inki Dae" <inki.dae@samsung.com>,
	"Seung-Woo Kim" <sw0312.kim@samsung.com>,
	"Kyungmin Park" <kyungmin.park@samsung.com>,
	"Krzysztof Kozlowski" <krzk@kernel.org>,
	"Alim Akhtar" <alim.akhtar@samsung.com>,
	"Hui Pu" <Hui.Pu@gehealthcare.com>,
	"Thomas Petazzoni" <thomas.petazzoni@bootlin.com>,
	<dri-devel@lists.freedesktop.org>, <linux-kernel@vger.kernel.org>,
	<linux-doc@vger.kernel.org>, <imx@lists.linux.dev>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-renesas-soc@vger.kernel.org>,
	<linux-amlogic@lists.infradead.org>,
	<linux-mediatek@lists.infradead.org>,
	<linux-samsung-soc@vger.kernel.org>
Subject: Re: [PATCH 06/26] drm/bridge: add devm_drm_of_find_bridge
Date: Tue, 16 Dec 2025 17:36:07 +0100	[thread overview]
Message-ID: <DEZSCVYVCZ71.1BRL4LGVYAZAX@bootlin.com> (raw)
In-Reply-To: <20251216-cute-bandicoot-of-authority-3c492a@penduick>

Hi Maxime,

On Tue Dec 16, 2025 at 2:49 PM CET, Maxime Ripard wrote:
[...]
>> Not sure why, but it's taking a while before I grasp your ideas about this
>> series and meld them with mine. I hopefully got a clear POV now, so based
>> on it my plan is to rework this series to:
>>
>>  * keep drm_of_find_bridge() but renamed to of_drm_get_bridge(), and keep
>>    patches 1-5 (with the changes suggested by you and Louis, nothing big
>>    and all already sent in v2)
>
> I don't think we should use that name, but on principle, yes.

OK about the rename. I just had sent this email before you requested the
rename. v3 is in the works with the of_drm_find_and_get_bridge() name.

>>  * not add devm_drm_of_find_bridge()
>
> Yep.
>
>>  * add next_bridge pointer to struct drm_bridge and call
>>    drm_bridge_put(bridge->next_bridge) in __drm_bridge_free, document it
>
> We don't have to at this point, you can add next_bridge to the
> drm_bridge pointer if you want, but I don't consider it a prerequisite.
> If we don't we would have to create drm_bridge_funcs->destroy
> implemnentations to give up the driver pointer reference though. Your
> call.

There's a destroy finc already, so I'm adding the next_bridge pointer in v3
along with some driver conversions, including one where the destroy hook is
needed.

>>  * convert patches 7-26 to use bridge->next_bridge where applicable,
>>    or to do something different when needed
>
> Depending on your decision above, we'd need to either convert them to
> use drm_bridge->next_bridge or create a destroy hook for them. Either
> way is fine for me.
>
>>  * maybe remove part of patches 7-26 just to reduce spam and rework effort
>>    in case of further iterations, to send them separately once the approach
>>    is accepted
>>
>> Does it look OK?

Cool, thanks for acking. v3 is just a testing round away from being sent.

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com