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 v3] backlight: gpio_backlight: Drop output gpio direction check for initial power state
Date: Fri, 21 Jul 2023 08:58:46 +0000 [thread overview]
Message-ID: <20230721090332.1528569-1-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:
---
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.
---
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>
---
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 8:58 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-21 8:58 Ying Liu [this message]
2023-07-21 9:10 ` [PATCH v3] backlight: gpio_backlight: Drop output gpio direction check for initial power state Andy Shevchenko
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