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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 903CFC4361B for ; Tue, 8 Dec 2020 04:45:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4659E23A58 for ; Tue, 8 Dec 2020 04:45:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726931AbgLHEp3 (ORCPT ); Mon, 7 Dec 2020 23:45:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60428 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725928AbgLHEp3 (ORCPT ); Mon, 7 Dec 2020 23:45:29 -0500 Received: from mail-ot1-x343.google.com (mail-ot1-x343.google.com [IPv6:2607:f8b0:4864:20::343]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE7D8C061749 for ; Mon, 7 Dec 2020 20:44:48 -0800 (PST) Received: by mail-ot1-x343.google.com with SMTP id b62so14789721otc.5 for ; Mon, 07 Dec 2020 20:44:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=S839lFMHy0MANqMX7LWPsNoTjUegKOQvqUVMPavlC6U=; b=cPp45lFN7EuWl0/lks1tVaMwk5uWFdxivYWhaGF4067O3UY2TYPjybuRmrsoFtp181 jyFkty98xB+dpDH/Zp5SKoBL3wi8wGd0kGbMVsZhtxnf0137Ty1SPv9l09C1H5VPQwp9 HRiG7CAvk+PSumHqbQbwSCBlSFG8ubvb4arPsbJvxl2JESREVz14KEqYdpolVA64eHFH 1FPJZ1ZiDhom6U4BDoehZBcOfU9UYbmqB/93NBcpYMGXD4TCxISBD9h6SOjDxKV8+RYP +wB9YGUsEaQ0lwqvvJTniFX0s2sEo176ugxVzL9gG51AsKz1nxAHyJm3LJzR1W1eWBmH 8Kfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=S839lFMHy0MANqMX7LWPsNoTjUegKOQvqUVMPavlC6U=; b=HBDSb0jHpmTZAu0fIgQB//D5w0f6LLcxOpU/Wy0YUP/bfffidmuYgBbzkQTYV0eDEf l7xNjAW2YKOum+XuNGUVAdgBf0hmmiN4t2lz5lydnquayQV5ERjqwGbOZR7Nf/rBjM3E M4OJAaP2OD52CWVc9J9TYQgJiLn7uTMn1aOadUCE6s4v478ZREpqTOt6hm1ToknXimyU GfF5eP/U+V2DNdzXA80zZXumBCaBagakaEODRpvUZke6RCx7yhJiyL2sWIrkfLgyPx6o WzyGDo3fgy2ov+C03Vb+9yG1hMzIVb7NB4AlI9pD8oDpvYNPqzP3I5P657dNQFnyfEOY TZFw== X-Gm-Message-State: AOAM530b6Xb8t6bTlmn1+V27PDzRcVZb5M+JupcFIlcFSCs0k2/I/gfT mMSfA2dVlnUJodEhsczXE+koaw== X-Google-Smtp-Source: ABdhPJyQpX+x8CsyAIpk0UarS+sOy31K736OMAOfCChjfjOwQ4qoP3bt78faRAsycAlt5uSGYTG+vg== X-Received: by 2002:a05:6830:11cc:: with SMTP id v12mr16250268otq.363.1607402688364; Mon, 07 Dec 2020 20:44:48 -0800 (PST) Received: from builder.lan (104-57-184-186.lightspeed.austtx.sbcglobal.net. [104.57.184.186]) by smtp.gmail.com with ESMTPSA id c19sm3171921otn.59.2020.12.07.20.44.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Dec 2020 20:44:47 -0800 (PST) From: Bjorn Andersson To: Thierry Reding , Sam Ravnborg , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH] drm/panel: Make backlight attachment lazy Date: Mon, 7 Dec 2020 22:44:46 -0600 Message-Id: <20201208044446.973238-1-bjorn.andersson@linaro.org> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some bridge chips, such as the TI SN65DSI86 DSI/eDP bridge, provides means of generating a PWM signal for backlight control of the attached panel. The provided PWM chip is typically controlled by the pwm-backlight driver, which if tied to the panel will provide DPMS. But with the current implementation the panel will refuse to probe because the bridge driver has yet to probe and register the PWM chip, and the bridge driver will refuse to probe because it's unable to find the panel. Mitigate this catch-22 situation by allowing the panel driver to probe and retry the attachment of the backlight as the panel is turned on or off. Signed-off-by: Bjorn Andersson --- drivers/gpu/drm/drm_panel.c | 47 +++++++++++++++++++++++++++---------- include/drm/drm_panel.h | 8 +++++++ 2 files changed, 43 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c index f634371c717a..7487329bd22d 100644 --- a/drivers/gpu/drm/drm_panel.c +++ b/drivers/gpu/drm/drm_panel.c @@ -43,6 +43,34 @@ static LIST_HEAD(panel_list); * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add(). */ +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE) +static int drm_panel_of_backlight_lazy(struct drm_panel *panel) +{ + struct backlight_device *backlight; + + if (!panel || !panel->dev) + return -EINVAL; + + backlight = devm_of_find_backlight(panel->dev); + + if (IS_ERR(backlight)) { + if (PTR_ERR(backlight) == -EPROBE_DEFER) { + panel->backlight_init_pending = true; + return 0; + } + + return PTR_ERR(backlight); + } + + panel->backlight = backlight; + panel->backlight_init_pending = false; + + return 0; +} +#else +static int drm_panel_of_backlight_lazy(struct drm_panel *panel) { return 0; } +#endif + /** * drm_panel_init - initialize a panel * @panel: DRM panel @@ -161,6 +189,9 @@ int drm_panel_enable(struct drm_panel *panel) return ret; } + if (panel->backlight_init_pending) + drm_panel_of_backlight_lazy(panel); + ret = backlight_enable(panel->backlight); if (ret < 0) DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n", @@ -187,6 +218,9 @@ int drm_panel_disable(struct drm_panel *panel) if (!panel) return -EINVAL; + if (panel->backlight_init_pending) + drm_panel_of_backlight_lazy(panel); + ret = backlight_disable(panel->backlight); if (ret < 0) DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n", @@ -328,18 +362,7 @@ EXPORT_SYMBOL(of_drm_get_panel_orientation); */ int drm_panel_of_backlight(struct drm_panel *panel) { - struct backlight_device *backlight; - - if (!panel || !panel->dev) - return -EINVAL; - - backlight = devm_of_find_backlight(panel->dev); - - if (IS_ERR(backlight)) - return PTR_ERR(backlight); - - panel->backlight = backlight; - return 0; + return drm_panel_of_backlight_lazy(panel); } EXPORT_SYMBOL(drm_panel_of_backlight); #endif diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h index 33605c3f0eba..b126abebb2f3 100644 --- a/include/drm/drm_panel.h +++ b/include/drm/drm_panel.h @@ -149,6 +149,14 @@ struct drm_panel { */ struct backlight_device *backlight; + /** + * @backlight_init_pending + * + * Backlight driver is not yet available so further attempts to + * initialize @backlight is necessary. + */ + bool backlight_init_pending; + /** * @funcs: * -- 2.29.2 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=-16.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 47F3EC4167B for ; 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[104.57.184.186]) by smtp.gmail.com with ESMTPSA id c19sm3171921otn.59.2020.12.07.20.44.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Dec 2020 20:44:47 -0800 (PST) From: Bjorn Andersson To: Thierry Reding , Sam Ravnborg , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter Subject: [RFC PATCH] drm/panel: Make backlight attachment lazy Date: Mon, 7 Dec 2020 22:44:46 -0600 Message-Id: <20201208044446.973238-1-bjorn.andersson@linaro.org> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 X-Mailman-Approved-At: Tue, 08 Dec 2020 08:32:06 +0000 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: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Some bridge chips, such as the TI SN65DSI86 DSI/eDP bridge, provides means of generating a PWM signal for backlight control of the attached panel. The provided PWM chip is typically controlled by the pwm-backlight driver, which if tied to the panel will provide DPMS. But with the current implementation the panel will refuse to probe because the bridge driver has yet to probe and register the PWM chip, and the bridge driver will refuse to probe because it's unable to find the panel. Mitigate this catch-22 situation by allowing the panel driver to probe and retry the attachment of the backlight as the panel is turned on or off. Signed-off-by: Bjorn Andersson --- drivers/gpu/drm/drm_panel.c | 47 +++++++++++++++++++++++++++---------- include/drm/drm_panel.h | 8 +++++++ 2 files changed, 43 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c index f634371c717a..7487329bd22d 100644 --- a/drivers/gpu/drm/drm_panel.c +++ b/drivers/gpu/drm/drm_panel.c @@ -43,6 +43,34 @@ static LIST_HEAD(panel_list); * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add(). */ +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE) +static int drm_panel_of_backlight_lazy(struct drm_panel *panel) +{ + struct backlight_device *backlight; + + if (!panel || !panel->dev) + return -EINVAL; + + backlight = devm_of_find_backlight(panel->dev); + + if (IS_ERR(backlight)) { + if (PTR_ERR(backlight) == -EPROBE_DEFER) { + panel->backlight_init_pending = true; + return 0; + } + + return PTR_ERR(backlight); + } + + panel->backlight = backlight; + panel->backlight_init_pending = false; + + return 0; +} +#else +static int drm_panel_of_backlight_lazy(struct drm_panel *panel) { return 0; } +#endif + /** * drm_panel_init - initialize a panel * @panel: DRM panel @@ -161,6 +189,9 @@ int drm_panel_enable(struct drm_panel *panel) return ret; } + if (panel->backlight_init_pending) + drm_panel_of_backlight_lazy(panel); + ret = backlight_enable(panel->backlight); if (ret < 0) DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n", @@ -187,6 +218,9 @@ int drm_panel_disable(struct drm_panel *panel) if (!panel) return -EINVAL; + if (panel->backlight_init_pending) + drm_panel_of_backlight_lazy(panel); + ret = backlight_disable(panel->backlight); if (ret < 0) DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n", @@ -328,18 +362,7 @@ EXPORT_SYMBOL(of_drm_get_panel_orientation); */ int drm_panel_of_backlight(struct drm_panel *panel) { - struct backlight_device *backlight; - - if (!panel || !panel->dev) - return -EINVAL; - - backlight = devm_of_find_backlight(panel->dev); - - if (IS_ERR(backlight)) - return PTR_ERR(backlight); - - panel->backlight = backlight; - return 0; + return drm_panel_of_backlight_lazy(panel); } EXPORT_SYMBOL(drm_panel_of_backlight); #endif diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h index 33605c3f0eba..b126abebb2f3 100644 --- a/include/drm/drm_panel.h +++ b/include/drm/drm_panel.h @@ -149,6 +149,14 @@ struct drm_panel { */ struct backlight_device *backlight; + /** + * @backlight_init_pending + * + * Backlight driver is not yet available so further attempts to + * initialize @backlight is necessary. + */ + bool backlight_init_pending; + /** * @funcs: * -- 2.29.2 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel