linux-kernel - Re: [PATCH 3/4] backlight: pwm_bl: Set scale type for CIE 1931 curves

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Message-ID: <3ef89251-146c-c4e4-91c8-19ae855824ac@collabora.com>
Date:   Wed, 19 Jun 2019 11:17:07 +0200
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Matthias Kaehlcke <mka@...omium.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Lee Jones <lee.jones@...aro.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Cc:     linux-pwm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Douglas Anderson <dianders@...omium.org>,
        Brian Norris <briannorris@...omium.org>,
        Pavel Machek <pavel@....cz>,
        Jacek Anaszewski <jacek.anaszewski@...il.com>
Subject: Re: [PATCH 3/4] backlight: pwm_bl: Set scale type for CIE 1931 curves

Hi Matthias,

On 13/6/19 21:43, Matthias Kaehlcke wrote:
> For backlight curves calculated with the CIE 1931 algorithm set
> the brightness scale type property accordingly. This makes the
> scale type available to userspace via the 'scale' sysfs attribute.
> 
> Signed-off-by: Matthias Kaehlcke <mka@...omium.org>

Tested on Samsung Chromebook Plus which uses the CIE 1931 algorithm.

Tested-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>

> ---
>  drivers/video/backlight/pwm_bl.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index fb45f866b923..f067fe7aa35d 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -553,6 +553,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
>  		goto err_alloc;
>  	}
>  
> +	memset(&props, 0, sizeof(struct backlight_properties));
> +
>  	if (data->levels) {
>  		/*
>  		 * For the DT case, only when brightness levels is defined
> @@ -591,6 +593,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
>  
>  			pb->levels = data->levels;
>  		}
> +
> +		props.scale = BACKLIGHT_SCALE_CIE1931;
>  	} else {
>  		/*
>  		 * That only happens for the non-DT case, where platform data
> @@ -601,7 +605,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
>  
>  	pb->lth_brightness = data->lth_brightness * (state.period / pb->scale);
>  
> -	memset(&props, 0, sizeof(struct backlight_properties));
>  	props.type = BACKLIGHT_RAW;
>  	props.max_brightness = data->max_brightness;
>  	bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,
>