From patchwork Sat Oct 19 08:35:50 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bartosz Golaszewski X-Patchwork-Id: 11200009 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 86A0E112B for ; Sat, 19 Oct 2019 08:36:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5BA1320872 for ; Sat, 19 Oct 2019 08:36:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=bgdev-pl.20150623.gappssmtp.com header.i=@bgdev-pl.20150623.gappssmtp.com header.b="0LLfhTrc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728328AbfJSIgw (ORCPT ); Sat, 19 Oct 2019 04:36:52 -0400 Received: from mail-wm1-f65.google.com ([209.85.128.65]:54858 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728305AbfJSIgP (ORCPT ); Sat, 19 Oct 2019 04:36:15 -0400 Received: by mail-wm1-f65.google.com with SMTP id p7so8371375wmp.4 for ; Sat, 19 Oct 2019 01:36:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bgdev-pl.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=+S1F9dGo/ErbKc+5MFUBRKg7ZKdxaGhAR9G3FlyzzL8=; b=0LLfhTrcJfkDD2KAFAf2MOHq0yJVpuFZpKnviLv848iy8t7hqY+CGdVLo3/g5BzAnP Vmh1RNwwivxdx6HOxcryCtVTIx1NP3zdU3hhJF4LXX8poyhw6UbZy12/dERrSdt7b5L9 TGO6h+x33e73YSGHYwVFplerlB38wTr663PRMwBBzMcgU2gIDpuQSYG5VDCkuoQh0T21 l4Tbe6CyZ6122rckrz/yK1AQZfrsa2U/DC2+ep4qqNVIvr2TqG5o4XGlnLdguOBzftfm DWBdQAc/YGRkHAthUyAoIVEN+OfKp5K8t/sUuhPJqeDIclC6LBHEW6SutvjPGJ3KyY7n K0DQ== 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=+S1F9dGo/ErbKc+5MFUBRKg7ZKdxaGhAR9G3FlyzzL8=; b=TJkb/cq9CoJA/npE/1qUPJoHnqy4XLfMY907Nw0Z9x7bNB+bzEmyd9LfH8hQZWFagw XyQ2DjXQSD2tgQ12T5npd6qvlmCaX+DjPoc9pFXIsxySwFVzF9KDloF8RG7MUPyTMer+ u0ym9gDDh/I2aA5heSgiR2l1cg6Vg3sNaQhJtGW2H/hR59DUjGwx4/ZA/96GhuwUPkQh XCr81WeYYAEFORlxiZMc5Ry7JKPQw/EqPIVntBXXkQg4QrqLv6bFv0IFm/MCBhuFoY/j iU8y6K67cezEo0ZOX/ns/N0d/jOP9uJLHJnrmJ8MLeU9I4c/DOrL4sfTs8M+ESMAeGRU mXOg== X-Gm-Message-State: APjAAAWqzQE0M9+RE/UwuSJC/33f2yWrvZthjvebqD75fVDNQJQMv6pa SkQy5Zz54AeF9vgMi3iR2xD4rQ== X-Google-Smtp-Source: APXvYqyGbXOURlCI3MAwmOrcJg5aZDgiyvPwiSPVXZJ2NBbEzH3nY7FwT+floFDAlMGcDtVWgxKA1w== X-Received: by 2002:a1c:8157:: with SMTP id c84mr10602738wmd.56.1571474173411; Sat, 19 Oct 2019 01:36:13 -0700 (PDT) Received: from debian-brgl.home ([2a01:cb1d:af:5b00:6d6c:8493:1ab5:dad7]) by smtp.gmail.com with ESMTPSA id u1sm7242627wmc.38.2019.10.19.01.36.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Oct 2019 01:36:12 -0700 (PDT) From: Bartosz Golaszewski To: Yoshinori Sato , Rich Felker , Lee Jones , Daniel Thompson , Jingoo Han , Bartlomiej Zolnierkiewicz , Linus Walleij , Andy Shevchenko , Jacopo Mondi Cc: linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, Bartosz Golaszewski Subject: [PATCH v6 3/9] backlight: gpio: explicitly set the direction of the GPIO Date: Sat, 19 Oct 2019 10:35:50 +0200 Message-Id: <20191019083556.19466-4-brgl@bgdev.pl> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191019083556.19466-1-brgl@bgdev.pl> References: <20191019083556.19466-1-brgl@bgdev.pl> MIME-Version: 1.0 Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org From: Bartosz Golaszewski The GPIO backlight driver currently requests the line 'as is', without acively setting its direction. This can lead to problems: if the line is in input mode by default, we won't be able to drive it later when updating the status and also reading its initial value doesn't make sense for backlight setting. Request the line 'as is' initially, so that we can read its value without affecting it but then change the direction to output explicitly when setting the initial brightness. Also: check the current direction and only read the value if it's output. Signed-off-by: Bartosz Golaszewski --- drivers/video/backlight/gpio_backlight.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c index 3955b513f2f8..a36ac3a45b81 100644 --- a/drivers/video/backlight/gpio_backlight.c +++ b/drivers/video/backlight/gpio_backlight.c @@ -25,9 +25,8 @@ struct gpio_backlight { int def_value; }; -static int gpio_backlight_update_status(struct backlight_device *bl) +static int gpio_backlight_get_curr_brightness(struct backlight_device *bl) { - struct gpio_backlight *gbl = bl_get_data(bl); int brightness = bl->props.brightness; if (bl->props.power != FB_BLANK_UNBLANK || @@ -35,6 +34,14 @@ static int gpio_backlight_update_status(struct backlight_device *bl) bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK)) brightness = 0; + return brightness; +} + +static int gpio_backlight_update_status(struct backlight_device *bl) +{ + struct gpio_backlight *gbl = bl_get_data(bl); + int brightness = gpio_backlight_get_curr_brightness(bl); + gpiod_set_value_cansleep(gbl->gpiod, brightness); return 0; @@ -85,7 +92,8 @@ static int gpio_backlight_initial_power_state(struct gpio_backlight *gbl) return gbl->def_value ? FB_BLANK_UNBLANK : FB_BLANK_POWERDOWN; /* if the enable GPIO is disabled, do not enable the backlight */ - if (gpiod_get_value_cansleep(gbl->gpiod) == 0) + if (gpiod_get_direction(gbl->gpiod) == 0 && + gpiod_get_value_cansleep(gbl->gpiod) == 0) return FB_BLANK_POWERDOWN; return FB_BLANK_UNBLANK; @@ -98,7 +106,7 @@ static int gpio_backlight_probe(struct platform_device *pdev) struct backlight_properties props; struct backlight_device *bl; struct gpio_backlight *gbl; - int ret; + int ret, init_brightness; gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL); if (gbl == NULL) @@ -151,7 +159,12 @@ static int gpio_backlight_probe(struct platform_device *pdev) bl->props.power = gpio_backlight_initial_power_state(gbl); bl->props.brightness = 1; - backlight_update_status(bl); + init_brightness = gpio_backlight_get_curr_brightness(bl); + ret = gpiod_direction_output(gbl->gpiod, init_brightness); + if (ret) { + dev_err(&pdev->dev, "failed to set initial brightness\n"); + return ret; + } platform_set_drvdata(pdev, bl); return 0;