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From: "andy@kernel.org" <andy@kernel.org>
To: Ying Liu <victor.liu@nxp.com>
Cc: "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>,
	"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>,
	"linus.walleij@linaro.org" <linus.walleij@linaro.org>,
	"brgl@bgdev.pl" <brgl@bgdev.pl>
Subject: Re: [PATCH v4] backlight: gpio_backlight: Drop output GPIO direction check for initial power state
Date: Fri, 21 Jul 2023 13:38:05 +0300	[thread overview]
Message-ID: <ZLpgDc1RNpYvOdMC@smile.fi.intel.com> (raw)
In-Reply-To: <20230721093342.1532531-1-victor.liu@nxp.com>

On Fri, Jul 21, 2023 at 09:29:03AM +0000, Ying Liu wrote:
> 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.

LGTM,
Reviewed-by: Andy Shevchenko <andy@kernel.org>

-- 
With Best Regards,
Andy Shevchenko



WARNING: multiple messages have this Message-ID (diff)
From: "andy@kernel.org" <andy@kernel.org>
To: Ying Liu <victor.liu@nxp.com>
Cc: "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>,
	"linux-fbdev@vger.kernel.org" <linux-fbdev@vger.kernel.org>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"brgl@bgdev.pl" <brgl@bgdev.pl>
Subject: Re: [PATCH v4] backlight: gpio_backlight: Drop output GPIO direction check for initial power state
Date: Fri, 21 Jul 2023 13:38:05 +0300	[thread overview]
Message-ID: <ZLpgDc1RNpYvOdMC@smile.fi.intel.com> (raw)
In-Reply-To: <20230721093342.1532531-1-victor.liu@nxp.com>

On Fri, Jul 21, 2023 at 09:29:03AM +0000, Ying Liu wrote:
> 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.

LGTM,
Reviewed-by: Andy Shevchenko <andy@kernel.org>

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2023-07-21 10:38 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-21  9:29 [PATCH v4] backlight: gpio_backlight: Drop output GPIO direction check for initial power state Ying Liu
2023-07-21  9:29 ` Ying Liu
2023-07-21 10:38 ` andy [this message]
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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