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 7BE97C02192 for ; Fri, 7 Feb 2025 08:59:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Content-Transfer-Encoding:Content-Type:MIME-Version:References:In-Reply-To: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=MXvhynDFLGl2VG/eD2ULksaHNrcYF1H4SjCXfYiNuEI=; b=r4uGsz6MRTRxS1 iqtNNYBMYbmj4oEF1TBDoF0Mh0vvecbslYgGpKjBj3hMimwdrBTN4nFKa+Eeu0s2Ntmddl+HJ3u9Z nNgGpVam32jPjYmquTK983UcycULjwO+o846wpnGlyBtuO3MQIntQhvnM/4fhR0UW0p3bFmGhkZ0q WtpTfnfWLWzak0ExxQUQnYuSHtbcuZV3WGsvkQ4wQTMxS5BRT4t85r2Ray5ObQwmURfIqlrf+HGjw LX3ckxg2B/aohIiK23Xi0YaKqxU8Oapl2X6ayYq5BhQArx+g3aL6UXXwBF9KeAb486cxQES+3cTU8 JL1PZc+PqNLjtotD8AXg==; 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x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgddvkeekgecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfitefpfffkpdcuggftfghnshhusghstghrihgsvgenuceurghilhhouhhtmecufedtudenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhepfffhvfevuffkjghfohfogggtgfesthejredtredtvdenucfhrhhomhepnfhutggrucevvghrvghsohhlihcuoehluhgtrgdrtggvrhgvshholhhisegsohhothhlihhnrdgtohhmqeenucggtffrrghtthgvrhhnpeeglefffefghefhtddvfeeufeeiveekgffgleekieduteekkeetvdehudekgfdvvdenucffohhmrghinhepsghoohhtlhhinhdrtghomhenucfkphepvdgrtddvmeeijedtmedvtddvtdemvggrtddumegtvgejvgemiegtgegvmeeitggtjeemleekgeejnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepvdgrtddvmeeijedtmedvtddvtdemvggrtddumegtvgejvgemiegtgegvmeeitggtjeemleekgeejpdhhvghlohepsghoohhthidpmhgrihhlfhhrohhmpehluhgtrgdrtggvrhgvshholhhisegsohhothhlihhnrdgtohhmpdhnsggprhgtphhtthhopeefjedprhgtphhtthhopegumhhithhrhidrsggrrhihshhhkhhovheslhhinhgrrhhordhorhhgpdhrtghpthhtohepshhimhhonhgrsehffhiflhhlrdgthhdprhgtphhtthhopehinhhkihdruggrvgesshgrmhhsuhhnghdrt ghomhdprhgtphhtthhopehjrghgrghnsegrmhgrrhhulhgrshholhhuthhiohhnshdrtghomhdprhgtphhtthhopehmrdhsiiihphhrohifshhkihesshgrmhhsuhhnghdrtghomhdprhgtphhtthhopegtrghtrghlihhnrdhmrghrihhnrghssegrrhhmrdgtohhmpdhrtghpthhtohepfihilhhlsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehshhgrfihnghhuoheskhgvrhhnvghlrdhorhhg X-GND-Sasl: luca.ceresoli@bootlin.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250207_005410_645757_80C3C9CD X-CRM114-Status: GOOD ( 43.80 ) 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: , Cc: Alexandre Belloni , =?UTF-8?Q?Herv?= =?UTF-8?Q?=C3=A9?= Codina , Thomas Petazzoni , linux-doc@vger.kernel.org, Catalin Marinas , Paul Kocialkowski , dri-devel@lists.freedesktop.org, Claudiu Beznea , Laurent Pinchart , Andrzej Hajda , David Airlie , Fabio Estevam , Marek Szyprowski , Simona Vetter , Robert Foss , Jonathan Corbet , Sam Ravnborg , Jernej Skrabec , Daniel Thompson , Jagan Teki , Jessica Zhang , Thomas Zimmermann , Will Deacon , Jonas Karlman , Sascha Hauer , Maarten Lankhorst , Maxime Ripard , Inki Dae , linux-arm-kernel@lists.infradead.org, Neil Armstrong , Boris Brezillon , linux-kernel@vger.kernel.org, Paul Kocialkowski , Pengutronix Kernel Team , Shawn Guo Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, 7 Feb 2025 04:55:54 +0200 Dmitry Baryshkov wrote: > On Thu, Feb 06, 2025 at 07:14:26PM +0100, Luca Ceresoli wrote: > > In order to support panels described either via graph links or via a > > subnode (e.g. "panel@0"), this driver uses low-level deprecated functions > > to find the next bridge. The resulting logic is complex and duplicates code > > already present in the DRM bridge core. Switch to the new APIs in DRM > > bridge core that allow to do the same in a much cleaner way. > > > > Note there are two slight changes in the new logic intended to improve the > > final result: > > > > * the old code looks for a subnode with any name except "port" or "ports", > > while the new code uses the node passed as a parameter > > > > * the old code looks for a subnode first and falls back to a graph link, > > while the new code uses the reverse order because graph links are the > > recommended device tree representation now > > > > The first change makes the code more robust by avoiding the risk of using > > an unrelated node which is not describing a panel and not names "port" or > > "ports". > > > > The second change is not expected to expose regressions because, in the > > cases where both a subnode and a graph link are used to describe a panel, > > the graph link should point to the subnode itself, such as in > > arch/arm64/boot/dts/qcom/sdm850-lenovo-yoga-c630.dts > > > > As a further cleanup, use a temporary variable to assign dsi->out_bridge > > only on success. This avoids the risk of leaving a non-NULL value in > > dsi->out_bridge when samsung_dsim_host_attach() fails. > > > > Suggested-by: Dmitry Baryshkov > > Signed-off-by: Luca Ceresoli > > > > --- > > > > This patch was added in v6. > > --- > > drivers/gpu/drm/bridge/samsung-dsim.c | 55 ++++++----------------------------- > > 1 file changed, 9 insertions(+), 46 deletions(-) > > > > diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c > > index f8b4fb8357659018ec0db65374ee5d05330639ae..bbd0a4f5a3f52b61bf48f10d6e8ca741bffa5e46 100644 > > --- a/drivers/gpu/drm/bridge/samsung-dsim.c > > +++ b/drivers/gpu/drm/bridge/samsung-dsim.c > > @@ -1704,55 +1704,16 @@ static int samsung_dsim_host_attach(struct mipi_dsi_host *host, > > const struct samsung_dsim_plat_data *pdata = dsi->plat_data; > > struct device *dev = dsi->dev; > > struct device_node *np = dev->of_node; > > - struct device_node *remote; > > - struct drm_panel *panel; > > + struct drm_bridge *out_bridge; > > int ret; > > > > - /* > > - * Devices can also be child nodes when we also control that device > > - * through the upstream device (ie, MIPI-DCS for a MIPI-DSI device). > > - * > > - * Lookup for a child node of the given parent that isn't either port > > - * or ports. > > - */ > > Please leave the comment in place (maybe rewrite it slightly). OK > > - for_each_available_child_of_node(np, remote) { > > - if (of_node_name_eq(remote, "port") || > > - of_node_name_eq(remote, "ports")) > > - continue; > > + out_bridge = devm_drm_of_get_bridge(dev, np, 1, 0); > > + if (IS_ERR(out_bridge) && PTR_ERR(out_bridge) != -EPROBE_DEFER) > > Can it actually return EPROBE_DEFER? It can't indeed. Dropping the second condition. > > > + out_bridge = devm_drm_of_get_bridge_by_node(dev, device->dev.of_node); > > > > - goto of_find_panel_or_bridge; > > - } > > - > > - /* > > - * 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; > > - > > - remote = of_graph_get_remote_node(np, 1, 0); > > - > > -of_find_panel_or_bridge: > > - if (!remote) > > - return -ENODEV; > > - > > - panel = of_drm_find_panel(remote); > > - if (!IS_ERR(panel)) { > > - dsi->out_bridge = devm_drm_panel_bridge_add(dev, panel); > > - } else { > > - dsi->out_bridge = of_drm_find_bridge(remote); > > - if (!dsi->out_bridge) > > - dsi->out_bridge = ERR_PTR(-EINVAL); > > - } > > - > > - of_node_put(remote); > > - > > - if (IS_ERR(dsi->out_bridge)) { > > - ret = PTR_ERR(dsi->out_bridge); > > - DRM_DEV_ERROR(dev, "failed to find the bridge: %d\n", ret); > > - return ret; > > + if (IS_ERR(out_bridge)) { > > + DRM_DEV_ERROR(dev, "failed to find the bridge: %ld\n", PTR_ERR(out_bridge)); > > + return PTR_ERR(out_bridge); > > } > > > > DRM_DEV_INFO(dev, "Attached %s device (lanes:%d bpp:%d mode-flags:0x%lx)\n", > > @@ -1784,6 +1745,8 @@ static int samsung_dsim_host_attach(struct mipi_dsi_host *host, > > dsi->format = device->format; > > dsi->mode_flags = device->mode_flags; > > > > + dsi->out_bridge = out_bridge; > > + > > Please move the assignment closer to the original place. OK. With this change it doesn't make sense to have a temporary out_bridge variable, so I'll drop it as well. Luca -- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com