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 X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9FFE4C07E95 for ; Tue, 20 Jul 2021 17:34:46 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3FA6B608FE for ; Tue, 20 Jul 2021 17:34:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3FA6B608FE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ravnborg.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id ADEE46E108; Tue, 20 Jul 2021 17:34:45 +0000 (UTC) Received: from mx2.smtp.larsendata.com (mx2.smtp.larsendata.com [91.221.196.228]) by gabe.freedesktop.org (Postfix) with ESMTPS id 743566E108 for ; Tue, 20 Jul 2021 17:34:44 +0000 (UTC) Received: from mail01.mxhotel.dk (mail01.mxhotel.dk [91.221.196.236]) by mx2.smtp.larsendata.com (Halon) with ESMTPS id caccbd04-e980-11eb-8d1a-0050568cd888; Tue, 20 Jul 2021 17:34:53 +0000 (UTC) Received: from ravnborg.org (80-162-45-141-cable.dk.customer.tdc.net [80.162.45.141]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: sam@ravnborg.org) by mail01.mxhotel.dk (Postfix) with ESMTPSA id A24F6194B7F; Tue, 20 Jul 2021 19:34:55 +0200 (CEST) Date: Tue, 20 Jul 2021 19:34:38 +0200 X-Report-Abuse-To: abuse@mxhotel.dk From: Sam Ravnborg To: Maxime Ripard Subject: Re: [PATCH 02/10] drm/bridge: Add a function to abstract away panels Message-ID: References: <20210720134525.563936-1-maxime@cerno.tech> <20210720134525.563936-3-maxime@cerno.tech> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210720134525.563936-3-maxime@cerno.tech> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Neil Armstrong , David Airlie , dri-devel@lists.freedesktop.org, Jonas Karlman , linux-kernel@vger.kernel.org, Robert Foss , Andrzej Hajda , Thierry Reding , Jernej Skrabec , Thomas Zimmermann , Daniel Vetter , Laurent Pinchart Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi Maxime, On Tue, Jul 20, 2021 at 03:45:17PM +0200, Maxime Ripard wrote: > Display drivers so far need to have a lot of boilerplate to first > retrieve either the panel or bridge that they are connected to using > drm_of_find_panel_or_bridge(), and then either deal with each with ad-hoc > functions or create a drm panel bridge through drm_panel_bridge_add. > > In order to reduce the boilerplate and hopefully create a path of least > resistance towards using the DRM panel bridge layer, let's create the > function devm_drm_of_get_next to reduce that boilerplate. > > Signed-off-by: Maxime Ripard > --- > drivers/gpu/drm/drm_bridge.c | 62 +++++++++++++++++++++++++++++++++--- > drivers/gpu/drm/drm_of.c | 3 ++ > include/drm/drm_bridge.h | 2 ++ > 3 files changed, 63 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c > index 044acd07c153..aef8c9f4fb9f 100644 > --- a/drivers/gpu/drm/drm_bridge.c > +++ b/drivers/gpu/drm/drm_bridge.c > @@ -24,10 +24,12 @@ > #include > #include > #include > +#include > > #include > #include > #include > +#include > > #include "drm_crtc_internal.h" > > @@ -50,10 +52,8 @@ > * > * Display drivers are responsible for linking encoders with the first bridge > * in the chains. This is done by acquiring the appropriate bridge with > - * of_drm_find_bridge() or drm_of_find_panel_or_bridge(), or creating it for a > - * panel with drm_panel_bridge_add_typed() (or the managed version > - * devm_drm_panel_bridge_add_typed()). Once acquired, the bridge shall be > - * attached to the encoder with a call to drm_bridge_attach(). > + * drm_of_get_next(). Once acquired, the bridge shall be attached to the > + * encoder with a call to drm_bridge_attach(). > * > * Bridges are responsible for linking themselves with the next bridge in the > * chain, if any. This is done the same way as for encoders, with the call to > @@ -1223,6 +1223,60 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np) > return NULL; > } > EXPORT_SYMBOL(of_drm_find_bridge); > + > +/** > + * devm_drm_of_get_next - Return next bridge in the chain I would prefer a more IMO descriptive name - something like this: devm_drm_of_get_bridge - Return a bridge or a panel wrapped as a bridge > + * @dev: device to tie the bridge lifetime to > + * @np: device tree node containing encoder output ports > + * @port: port in the device tree node > + * @endpoint: endpoint in the device tree node > + * > + * Given a DT node's port and endpoint number, finds the connected node > + * and returns the associated bridge if any, or creates and returns a > + * drm panel bridge instance if a panel is connected. > + * > + * Returns a pointer to the bridge if successful, or an error pointer > + * otherwise. > + */ > +struct drm_bridge *devm_drm_of_get_next(struct device *dev, > + struct device_node *np, > + unsigned int port, > + unsigned int endpoint) > +{ > + struct device_node *remote; > + struct drm_bridge *bridge; > + struct drm_panel *panel; > + > + /* > + * 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 ERR_PTR(-ENODEV); > + > + remote = of_graph_get_remote_node(np, port, endpoint); > + if (!remote) > + return ERR_PTR(-ENODEV); > + > + bridge = of_drm_find_bridge(remote); > + if (bridge) { > + of_node_put(remote); > + return bridge; > + } > + > + panel = of_drm_find_panel(remote); > + if (IS_ERR(panel)) { > + of_node_put(remote); > + return ERR_CAST(panel); > + } Here panel may be NULL which is unhadled, as devm_drm_panel_bridge_add() will fault if the passed panel pointer is NULL. Sam > + > + of_node_put(remote); > + > + return devm_drm_panel_bridge_add(dev, panel); > +} > +EXPORT_SYMBOL(devm_drm_of_get_next); > #endif > > MODULE_AUTHOR("Ajay Kumar "); > diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c > index 997b8827fed2..bbbdc4d17ac9 100644 > --- a/drivers/gpu/drm/drm_of.c > +++ b/drivers/gpu/drm/drm_of.c > @@ -231,6 +231,9 @@ EXPORT_SYMBOL_GPL(drm_of_encoder_active_endpoint); > * return either the associated struct drm_panel or drm_bridge device. Either > * @panel or @bridge must not be NULL. > * > + * This function is deprecated and should not be used in new drivers. Use > + * drm_of_get_next() instead. > + * > * Returns zero if successful, or one of the standard error codes if it fails. > */ > int drm_of_find_panel_or_bridge(const struct device_node *np, > diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h > index 46bdfa48c413..e16fafc6f37d 100644 > --- a/include/drm/drm_bridge.h > +++ b/include/drm/drm_bridge.h > @@ -911,6 +911,8 @@ struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev, > struct drm_bridge *devm_drm_panel_bridge_add_typed(struct device *dev, > struct drm_panel *panel, > u32 connector_type); > +struct drm_bridge *devm_drm_of_get_next(struct device *dev, struct device_node *node, > + unsigned int port, unsigned int endpoint); > struct drm_connector *drm_panel_bridge_connector(struct drm_bridge *bridge); > #endif > > -- > 2.31.1