From: Ying Liu <victor.liu@nxp.com> To: "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>, "linux-fbdev@vger.kernel.org" <linux-fbdev@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Cc: "lee@kernel.org" <lee@kernel.org>, "daniel.thompson@linaro.org" <daniel.thompson@linaro.org>, "jingoohan1@gmail.com" <jingoohan1@gmail.com>, "deller@gmx.de" <deller@gmx.de>, "andy@kernel.org" <andy@kernel.org>, "linus.walleij@linaro.org" <linus.walleij@linaro.org>, "brgl@bgdev.pl" <brgl@bgdev.pl> Subject: [PATCH v4] backlight: gpio_backlight: Drop output GPIO direction check for initial power state Date: Fri, 21 Jul 2023 09:29:03 +0000 [thread overview] Message-ID: <20230721093342.1532531-1-victor.liu@nxp.com> (raw) If GPIO pin is in input state but backlight is currently off due to default pull downs, then initial power state is set to FB_BLANK_UNBLANK in DT boot mode with phandle link and the backlight is effectively turned on in gpio_backlight_probe(), which is undesirable according to patch description of commit ec665b756e6f ("backlight: gpio-backlight: Correct initial power state handling"). Quote: ---8<--- If in DT boot we have phandle link then leave the GPIO in a state which the bootloader left it and let the user of the backlight to configure it further. ---8<--- So, let's drop output GPIO direction check and only check GPIO value to set the initial power state. Fixes: 706dc68102bc ("backlight: gpio: Explicitly set the direction of the GPIO") Signed-off-by: Liu Ying <victor.liu@nxp.com> --- v3->v4: * Capitalize words 'gpio' in patch description. (Andy) * Capitalize word 'gpio' in patch title. * Quote appropriately in patch description. (Andy) v2->v3: * Add Fixes tag. (Daniel) v1->v2: * Improve patch description. (Daniel, Bartosz, Andy) drivers/video/backlight/gpio_backlight.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c index 6f78d928f054..38c46936fdcd 100644 --- a/drivers/video/backlight/gpio_backlight.c +++ b/drivers/video/backlight/gpio_backlight.c @@ -87,8 +87,7 @@ static int gpio_backlight_probe(struct platform_device *pdev) /* Not booted with device tree or no phandle link to the node */ bl->props.power = def_value ? FB_BLANK_UNBLANK : FB_BLANK_POWERDOWN; - else if (gpiod_get_direction(gbl->gpiod) == 0 && - gpiod_get_value_cansleep(gbl->gpiod) == 0) + else if (gpiod_get_value_cansleep(gbl->gpiod) == 0) bl->props.power = FB_BLANK_POWERDOWN; else bl->props.power = FB_BLANK_UNBLANK; -- 2.37.1
WARNING: multiple messages have this Message-ID (diff)
From: Ying Liu <victor.liu@nxp.com> To: "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>, "linux-fbdev@vger.kernel.org" <linux-fbdev@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Cc: "andy@kernel.org" <andy@kernel.org>, "daniel.thompson@linaro.org" <daniel.thompson@linaro.org>, "jingoohan1@gmail.com" <jingoohan1@gmail.com>, "deller@gmx.de" <deller@gmx.de>, "lee@kernel.org" <lee@kernel.org>, "brgl@bgdev.pl" <brgl@bgdev.pl> Subject: [PATCH v4] backlight: gpio_backlight: Drop output GPIO direction check for initial power state Date: Fri, 21 Jul 2023 09:29:03 +0000 [thread overview] Message-ID: <20230721093342.1532531-1-victor.liu@nxp.com> (raw) If GPIO pin is in input state but backlight is currently off due to default pull downs, then initial power state is set to FB_BLANK_UNBLANK in DT boot mode with phandle link and the backlight is effectively turned on in gpio_backlight_probe(), which is undesirable according to patch description of commit ec665b756e6f ("backlight: gpio-backlight: Correct initial power state handling"). Quote: ---8<--- If in DT boot we have phandle link then leave the GPIO in a state which the bootloader left it and let the user of the backlight to configure it further. ---8<--- So, let's drop output GPIO direction check and only check GPIO value to set the initial power state. Fixes: 706dc68102bc ("backlight: gpio: Explicitly set the direction of the GPIO") Signed-off-by: Liu Ying <victor.liu@nxp.com> --- v3->v4: * Capitalize words 'gpio' in patch description. (Andy) * Capitalize word 'gpio' in patch title. * Quote appropriately in patch description. (Andy) v2->v3: * Add Fixes tag. (Daniel) v1->v2: * Improve patch description. (Daniel, Bartosz, Andy) drivers/video/backlight/gpio_backlight.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c index 6f78d928f054..38c46936fdcd 100644 --- a/drivers/video/backlight/gpio_backlight.c +++ b/drivers/video/backlight/gpio_backlight.c @@ -87,8 +87,7 @@ static int gpio_backlight_probe(struct platform_device *pdev) /* Not booted with device tree or no phandle link to the node */ bl->props.power = def_value ? FB_BLANK_UNBLANK : FB_BLANK_POWERDOWN; - else if (gpiod_get_direction(gbl->gpiod) == 0 && - gpiod_get_value_cansleep(gbl->gpiod) == 0) + else if (gpiod_get_value_cansleep(gbl->gpiod) == 0) bl->props.power = FB_BLANK_POWERDOWN; else bl->props.power = FB_BLANK_UNBLANK; -- 2.37.1
next reply other threads:[~2023-07-21 9:29 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-07-21 9:29 Ying Liu [this message] 2023-07-21 9:29 ` [PATCH v4] backlight: gpio_backlight: Drop output GPIO direction check for initial power state Ying Liu 2023-07-21 10:38 ` andy 2023-07-21 10:38 ` andy 2023-07-21 11:07 ` Bartosz Golaszewski 2023-07-21 11:07 ` Bartosz Golaszewski 2023-07-24 17:46 ` Linus Walleij 2023-07-24 17:46 ` Linus Walleij 2023-07-28 11:14 ` (subset) " Lee Jones 2023-07-28 11:14 ` Lee Jones
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