linux-kernel - Re: [PATCH 01/15] video: fbdev: atmel

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Date:   Mon, 09 Jan 2023 11:14:53 +0200
From:   Jani Nikula <jani.nikula@...ux.intel.com>
To:     Sam Ravnborg via B4 Submission Endpoint 
        <devnull+sam.ravnborg.org@...nel.org>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Helge Deller <deller@....de>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Claudiu Beznea <claudiu.beznea@...rochip.com>,
        Antonino Daplas <adaplas@...il.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Robin van der Gracht <robin@...tonic.nl>,
        Miguel Ojeda <ojeda@...nel.org>, Lee Jones <lee@...nel.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>
Cc:     linux-fbdev@...r.kernel.org, Stephen Kitt <steve@....org>,
        Sam Ravnborg <sam@...nborg.org>, linux-staging@...ts.linux.dev,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        Ludovic Desroches <ludovic.desroches@...rochip.com>,
        linux-omap@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 01/15] video: fbdev: atmel_lcdfb: Rework backlight handling

On Sat, 07 Jan 2023, Sam Ravnborg via B4 Submission Endpoint <devnull+sam.ravnborg.org@...nel.org> wrote:
> From: Sam Ravnborg <sam@...nborg.org>
>
> The atmel_lcdfb had code to save/restore power state.
> This is not needed so drop it.
>
> Introduce backlight_is_brightness() to make logic simpler.

backlight_is_brightness?

BR,
Jani.


>
> Signed-off-by: Sam Ravnborg <sam@...nborg.org>
> Cc: Nicolas Ferre <nicolas.ferre@...rochip.com>
> Cc: Alexandre Belloni <alexandre.belloni@...tlin.com>
> Cc: Ludovic Desroches <ludovic.desroches@...rochip.com>
> Cc: linux-fbdev@...r.kernel.org
> Cc: linux-arm-kernel@...ts.infradead.org
> ---
>  drivers/video/fbdev/atmel_lcdfb.c | 24 +++---------------------
>  1 file changed, 3 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/video/fbdev/atmel_lcdfb.c b/drivers/video/fbdev/atmel_lcdfb.c
> index 1fc8de4ecbeb..d297b3892637 100644
> --- a/drivers/video/fbdev/atmel_lcdfb.c
> +++ b/drivers/video/fbdev/atmel_lcdfb.c
> @@ -49,7 +49,6 @@ struct atmel_lcdfb_info {
>  	struct clk		*lcdc_clk;
>  
>  	struct backlight_device	*backlight;
> -	u8			bl_power;
>  	u8			saved_lcdcon;
>  
>  	u32			pseudo_palette[16];
> @@ -109,32 +108,18 @@ static u32 contrast_ctr = ATMEL_LCDC_PS_DIV8
>  static int atmel_bl_update_status(struct backlight_device *bl)
>  {
>  	struct atmel_lcdfb_info *sinfo = bl_get_data(bl);
> -	int			power = sinfo->bl_power;
> -	int			brightness = bl->props.brightness;
> +	int brightness;
>  
> -	/* REVISIT there may be a meaningful difference between
> -	 * fb_blank and power ... there seem to be some cases
> -	 * this doesn't handle correctly.
> -	 */
> -	if (bl->props.fb_blank != sinfo->bl_power)
> -		power = bl->props.fb_blank;
> -	else if (bl->props.power != sinfo->bl_power)
> -		power = bl->props.power;
> -
> -	if (brightness < 0 && power == FB_BLANK_UNBLANK)
> -		brightness = lcdc_readl(sinfo, ATMEL_LCDC_CONTRAST_VAL);
> -	else if (power != FB_BLANK_UNBLANK)
> -		brightness = 0;
> +	brightness = backlight_get_brightness(bl);
>  
>  	lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_VAL, brightness);
> +
>  	if (contrast_ctr & ATMEL_LCDC_POL_POSITIVE)
>  		lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_CTR,
>  			brightness ? contrast_ctr : 0);
>  	else
>  		lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_CTR, contrast_ctr);
>  
> -	bl->props.fb_blank = bl->props.power = sinfo->bl_power = power;
> -
>  	return 0;
>  }
>  
> @@ -155,8 +140,6 @@ static void init_backlight(struct atmel_lcdfb_info *sinfo)
>  	struct backlight_properties props;
>  	struct backlight_device	*bl;
>  
> -	sinfo->bl_power = FB_BLANK_UNBLANK;
> -
>  	if (sinfo->backlight)
>  		return;
>  
> @@ -173,7 +156,6 @@ static void init_backlight(struct atmel_lcdfb_info *sinfo)
>  	sinfo->backlight = bl;
>  
>  	bl->props.power = FB_BLANK_UNBLANK;
> -	bl->props.fb_blank = FB_BLANK_UNBLANK;
>  	bl->props.brightness = atmel_bl_get_brightness(bl);
>  }

-- 
Jani Nikula, Intel Open Source Graphics Center