linux-kernel - Re: [PATCH v2] fbdev: atmel_lcdfb: Rework backlight status updates

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Date:   Thu, 9 Jun 2022 20:55:37 +0200
From:   Sam Ravnborg <sam@...nborg.org>
To:     Stephen Kitt <steve@....org>
Cc:     Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Claudiu Beznea <claudiu.beznea@...rochip.com>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Helge Deller <deller@....de>, linux-fbdev@...r.kernel.org,
        dri-devel@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] fbdev: atmel_lcdfb: Rework backlight status updates

Hi Stephen, thanks!
On Thu, Jun 09, 2022 at 08:04:40PM +0200, Stephen Kitt wrote:
> Instead of checking the state of various backlight_properties fields
> against the memorised state in atmel_lcdfb_info.bl_power,
> atmel_bl_update_status() should retrieve the desired state using
> backlight_get_brightness (which takes into account the power state,
> blanking etc.). This means the explicit checks using props.fb_blank
> and props.power can be dropped.
> 
> The backlight framework ensures that backlight is never negative, so
> the test before reading the brightness from the hardware always ends
> up false and the whole block can be removed. The framework retrieves
> the brightness from the hardware through atmel_bl_get_brightness()
> when necessary.
> 
> As a result, bl_power in struct atmel_lcdfb_info is no longer
> necessary, so remove that while we're at it. Since we only ever care
> about reading the current state in backlight_properties, drop the
> updates at the end of the function.
> 
> Signed-off-by: Stephen Kitt <steve@....org>
> Cc: Nicolas Ferre <nicolas.ferre@...rochip.com>
> Cc: Helge Deller <deller@....de>
> Cc: Alexandre Belloni <alexandre.belloni@...tlin.com>
> Cc: Claudiu Beznea <claudiu.beznea@...rochip.com>
> Cc: linux-fbdev@...r.kernel.org
> Cc: dri-devel@...ts.freedesktop.org
> Cc: linux-arm-kernel@...ts.infradead.org
Acked-by: Sam Ravnborg <sam@...nborg.org>

	Sam