From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9B3CFF34C49 for ; Mon, 13 Apr 2026 13:59:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Cc:To:In-Reply-To:References :Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=6uVyC++V1UmVV258SySNjnH/QWEzHB3vGKW3rS3VhpE=; b=xhL+hJS4ZqfWQmtwlD4AJMx5WB +neYCAUAWOGYTAc+j4TnDsIAU3FEoYGImOXFEcyMepRaLCuy78ObEdaKK1HTTvip0Awu29932w0HX uG42AuCNtzUmpeHVswQ+Js4HKi5oA+r1re/WpYdNcm5QJebPFBStaI6ZWgXY9x0e4JJrgApNSkw9x TkkvGHLU2n9Bd1P4H7wWM4YIK6nwtoo2oCbeVBL19sUb5pXgkao5KsoWJrEQRxoa1goZ2pGKGkkSa udx525/KBh6PJIFTmOowfT0ZhFtRLwMUCYHJ80U8a5CU25QI3fjWDqGnvdogCx1lXe/zqmj8Rp2vt F85nru0A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wCHoX-0000000FngG-37pk; Mon, 13 Apr 2026 13:58:57 +0000 Received: from smtpout-03.galae.net ([185.246.85.4]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wCHoU-0000000Fnea-3QtE for linux-arm-kernel@lists.infradead.org; Mon, 13 Apr 2026 13:58:56 +0000 Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-03.galae.net (Postfix) with ESMTPS id 06EB94E429EA; Mon, 13 Apr 2026 13:58:53 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id C4FA75FFB9; Mon, 13 Apr 2026 13:58:52 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 8366410450084; Mon, 13 Apr 2026 15:58:47 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1776088731; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=6uVyC++V1UmVV258SySNjnH/QWEzHB3vGKW3rS3VhpE=; b=z/IAyX3cr6ydhmF+62EMz8NfkSsjebBn7/omwngWBm8Nn4uyX7nYklonTQ5fXdLL5QiOYy +1THmm5QjgiJqYt3Gx6EHZqO1sYrGB5+soslEjRulOl7J0x7FLcZRIV7rOcXvFvfvjQPS3 WpTDOcLtHwMq4fovz2LnVZRTWM3zCfi+WcZwtPZkqWq6hglUMRpXS6gA+3cjLhRjk/EjWx +ENFvJi4VWk66EXtK3T72MsaL/pERdNNZTfe8S9pK84OG09lOVXS/NVr5a8rhwY120mzk2 gWIkuNkFFsjLlXjxZerjx1HbvuXqJ8hxOjxcp8YXLCaId3XpvSlQWExCz5zH5A== From: Luca Ceresoli Date: Mon, 13 Apr 2026 15:58:33 +0200 Subject: [PATCH 01/10] drm/bridge: add of_drm_get_bridge_by_endpoint() MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260413-drm-bridge-alloc-getput-panel_or_bridge-v1-1-acd01cd79a1f@bootlin.com> References: <20260413-drm-bridge-alloc-getput-panel_or_bridge-v1-0-acd01cd79a1f@bootlin.com> In-Reply-To: <20260413-drm-bridge-alloc-getput-panel_or_bridge-v1-0-acd01cd79a1f@bootlin.com> To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Clark , Dmitry Baryshkov , Abhinav Kumar , Jessica Zhang , Sean Paul , Marijn Suijten , Xinliang Liu , Tian Tao , Xinwei Kong , Sumit Semwal , Yongqin Liu , John Stultz , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Tomi Valkeinen , Michal Simek Cc: Hui Pu , Ian Ray , Thomas Petazzoni , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, Luca Ceresoli X-Mailer: b4 0.15.1 X-Last-TLS-Session-Version: TLSv1.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260413_065855_125845_A375FB8F X-CRM114-Status: GOOD ( 17.79 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org drm_of_find_panel_or_bridge() is widely used, but many callers pass NULL into the @panel or the @bridge arguments, thus making a very partial usage of this rather complex function. Besides, the bridge returned in @bridge is not refcounted, thus making this API unsafe when DRM bridge hotplug will be introduced. Solve both issues for the cases of calls to drm_of_find_panel_or_bridge() with a NULL @panel pointer by adding a new function that only looks for bridges (and is thus much simpler) and increments the refcount of the returned bridge. The new function is identical to drm_of_find_panel_or_bridge() except it: - handles bridge refcounting: uses of_drm_find_and_get_bridge() instead of of_drm_find_bridge() internally to return a refcounted bridge - is slightly simpler to use: just takes no @panel parameter - has a simpler implementation: it is equal to drm_of_find_panel_or_bridge() after removing the code that becomes dead when @panel == NULL Also add this function to drm_bridge.c and not drm_of.c because it returns bridges only. Signed-off-by: Luca Ceresoli --- drivers/gpu/drm/drm_bridge.c | 46 ++++++++++++++++++++++++++++++++++++++++++++ include/drm/drm_bridge.h | 9 +++++++++ 2 files changed, 55 insertions(+) diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index ba80bebb5685..e51990b74417 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -1581,6 +1581,52 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np) return bridge; } EXPORT_SYMBOL(of_drm_find_bridge); + +/** + * of_drm_get_bridge_by_endpoint - return DRM bridge connected to a port/endpoint + * @np: device tree node containing output ports + * @port: port in the device tree node, or -1 for the first port found + * @endpoint: endpoint in the device tree node, or -1 for the first endpoint found + * @bridge: pointer to hold returned drm_bridge, must not be NULL + * + * Given a DT node's port and endpoint number, find the connected node and + * return the associated drm_bridge device. + * + * The refcount of the returned bridge is incremented. Use drm_bridge_put() + * when done with it. + * + * Returns zero (and sets *bridge to a valid bridge pointer) if successful, + * or one of the standard error codes (and the value in *bridge is + * unspecified) if it fails. + */ +int of_drm_get_bridge_by_endpoint(const struct device_node *np, + int port, int endpoint, + struct drm_bridge **bridge) +{ + if (!bridge) + return -EINVAL; + + /* + * of_graph_get_remote_node() produces a noisy error message if port + * node isn't found and the absence of the port is a legit case here, + * so at first we silently check whether graph presents in the + * device-tree node. + */ + if (!of_graph_is_present(np)) + return -ENODEV; + + struct device_node *remote __free(device_node) = + of_graph_get_remote_node(np, port, endpoint); + if (!remote) + return -ENODEV; + + *bridge = of_drm_find_and_get_bridge(remote); + if (*bridge) + return 0; + + return -EPROBE_DEFER; +} +EXPORT_SYMBOL_GPL(of_drm_get_bridge_by_endpoint); #endif /** diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index a8d67bd9ee50..ad93597cd622 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -1327,6 +1327,9 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge, #ifdef CONFIG_OF struct drm_bridge *of_drm_find_and_get_bridge(struct device_node *np); struct drm_bridge *of_drm_find_bridge(struct device_node *np); +int of_drm_get_bridge_by_endpoint(const struct device_node *np, + int port, int endpoint, + struct drm_bridge **bridge); #else static inline struct drm_bridge *of_drm_find_and_get_bridge(struct device_node *np) { @@ -1336,6 +1339,12 @@ static inline struct drm_bridge *of_drm_find_bridge(struct device_node *np) { return NULL; } +static inline int of_drm_get_bridge_by_endpoint(const struct device_node *np, + int port, int endpoint, + struct drm_bridge **bridge) +{ + return -ENODEV; +} #endif static inline bool drm_bridge_is_last(struct drm_bridge *bridge) -- 2.53.0