linux-kernel - Re: [PATCH v6 10/26] drm/bridge: add devm_drm_of_get_bridge_by

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250210-vague-fluorescent-toad-c7d1ce@houat>
Date: Mon, 10 Feb 2025 19:22:15 +0100
From: Maxime Ripard <mripard@...nel.org>
To: Luca Ceresoli <luca.ceresoli@...tlin.com>
Cc: Simona Vetter <simona@...ll.ch>, Inki Dae <inki.dae@...sung.com>, 
	Jagan Teki <jagan@...rulasolutions.com>, Marek Szyprowski <m.szyprowski@...sung.com>, 
	Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, Shawn Guo <shawnguo@...nel.org>, 
	Sascha Hauer <s.hauer@...gutronix.de>, Pengutronix Kernel Team <kernel@...gutronix.de>, 
	Fabio Estevam <festevam@...il.com>, Daniel Thompson <danielt@...nel.org>, 
	Andrzej Hajda <andrzej.hajda@...el.com>, Jonathan Corbet <corbet@....net>, 
	Sam Ravnborg <sam@...nborg.org>, Boris Brezillon <bbrezillon@...nel.org>, 
	Nicolas Ferre <nicolas.ferre@...rochip.com>, Alexandre Belloni <alexandre.belloni@...tlin.com>, 
	Claudiu Beznea <claudiu.beznea@...on.dev>, Jessica Zhang <quic_jesszhan@...cinc.com>, 
	Paul Kocialkowski <contact@...lk.fr>, Dmitry Baryshkov <dmitry.baryshkov@...aro.org>, 
	Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>, Jonas Karlman <jonas@...boo.se>, 
	Jernej Skrabec <jernej.skrabec@...il.com>, Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
	Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, 
	Hervé Codina <herve.codina@...tlin.com>, Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
	linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org, linux-doc@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, Paul Kocialkowski <paul.kocialkowski@...tlin.com>
Subject: Re: [PATCH v6 10/26] drm/bridge: add devm_drm_of_get_bridge_by_node()

On Thu, Feb 06, 2025 at 07:14:25PM +0100, Luca Ceresoli wrote:
> devm_drm_of_get_bridge(), which is based on graph links, is the recommended
> function to get a pointer to the following bridge.
> 
> This is valid even for panels, for which the recommended device tree
> description is via graph links and not (or not only) panel subnodes of a
> panel controller (e.g. "dsi@...4" controller node with a "panel@0"
> subnode).
> 
> However there are drivers supporting the panel subnode description in
> addition to the graph links. For those drivers add a _by_node variant that
> takes the node of the target node.
> 
> Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> Signed-off-by: Luca Ceresoli <luca.ceresoli@...tlin.com>
> 
> ---
> 
> This patch was added in v6.
> ---
>  drivers/gpu/drm/drm_bridge.c | 30 ++++++++++++++++++++++++++++++
>  include/drm/drm_bridge.h     |  8 ++++++++
>  2 files changed, 38 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index 2aa17fbe538b86066c4e68f0d0e8046e9ca9b965..b0834b8644284e5f7751cec81724af849b4180e7 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -1407,6 +1407,36 @@ struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,
>  }
>  EXPORT_SYMBOL(devm_drm_of_get_bridge);
>  
> +/**
> + * devm_drm_of_get_bridge_by_node - Return bridge for a given OF node
> + * @dev: device to tie the bridge lifetime to
> + * @bridge_node: device node of the remote bridge
> + *
> + * Given a bridge DT node, returns the associated bridge if any. This
> + * should be used in addition to devm_drm_of_get_bridge() when the regular
> + * graph link search is not enough, e.g. for drivers that need to support
> + * panels described only as subnodes.
> + *
> + * RETURNS:
> + * A pointer to the bridge if successful, or an error pointer otherwise.
> + */
> +struct drm_bridge *devm_drm_of_get_bridge_by_node(struct device *dev,
> +						  struct device_node *bridge_node)
> +{
> +	struct drm_bridge *bridge;
> +	int ret;
> +
> +	if (!bridge_node)
> +		return ERR_PTR(-EINVAL);
> +
> +	bridge = of_drm_find_bridge(bridge_node);
> +	if (!bridge)
> +		return ERR_PTR(-ENODEV);
> +
> +	return bridge;
> +}
> +EXPORT_SYMBOL(devm_drm_of_get_bridge_by_node);
> +

A bridge is a KMS-facing structure, there's no reason to tie it to the
lifetime of the device.

Maxime

Download attachment "signature.asc" of type "application/pgp-signature" (274 bytes)