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Date:   Fri, 21 Jul 2023 09:42:51 +0100
From:   Daniel Thompson <daniel.thompson@linaro.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>,
        "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: Re: [PATCH v2] backlight: gpio_backlight: Drop output gpio direction
 check for initial power state
Message-ID: <20230721084251.GF2525277@aspen.lan>
References: <20230721073555.1377236-1-victor.liu@nxp.com>
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In-Reply-To: <20230721073555.1377236-1-victor.liu@nxp.com>
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On Fri, Jul 21, 2023 at 07:31:37AM +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:
> ---
> 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.
>
> Signed-off-by: Liu Ying <victor.liu@nxp.com>

Based on the discussion for v1 about 706dc68102bc ("backlight: gpio:
Explicitly set the direction of the GPIO"), I think there should
be a Fixes: tag here.


Daniel.