linux-kernel - Re: [PATCH 09/15] staging: fbtft: fb_ssd1351.c: Introduce backlight_is

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Date:   Sun, 8 Jan 2023 20:28:17 +0100
From:   Stephen Kitt <steve@....org>
To:     Sam Ravnborg via B4 Submission Endpoint 
        <devnull+sam.ravnborg.org@...nel.org>
Cc:     <sam@...nborg.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>, linux-fbdev@...r.kernel.org,
        dri-devel@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-omap@...r.kernel.org, linux-staging@...ts.linux.dev,
        linuxppc-dev@...ts.ozlabs.org,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [PATCH 09/15] staging: fbtft: fb_ssd1351.c: Introduce
 backlight_is_blank()

On Sat, 07 Jan 2023 19:26:23 +0100, Sam Ravnborg via B4 Submission Endpoint
<devnull+sam.ravnborg.org@...nel.org> wrote:

> From: Sam Ravnborg <sam@...nborg.org>
> 
> Avoiding direct access to backlight_properties.props.
> 
> Access to the deprecated props.fb_blank replaced by backlight_is_blank().
> Access to props.power is dropped - it was only used for debug.
> 
> Signed-off-by: Sam Ravnborg <sam@...nborg.org>
> Cc: Stephen Kitt <steve@....org>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: Daniel Thompson <daniel.thompson@...aro.org>
> Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Cc: linux-fbdev@...r.kernel.org
> ---
>  drivers/staging/fbtft/fb_ssd1351.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/staging/fbtft/fb_ssd1351.c
> b/drivers/staging/fbtft/fb_ssd1351.c index b8d55aa8c5c7..995fbd2f3dc6 100644
> --- a/drivers/staging/fbtft/fb_ssd1351.c
> +++ b/drivers/staging/fbtft/fb_ssd1351.c
> @@ -190,15 +190,12 @@ static struct fbtft_display display = {
>  static int update_onboard_backlight(struct backlight_device *bd)
>  {
>  	struct fbtft_par *par = bl_get_data(bd);
> -	bool on;
> +	bool blank = backlight_is_blank(bd);
>  
> -	fbtft_par_dbg(DEBUG_BACKLIGHT, par,
> -		      "%s: power=%d, fb_blank=%d\n",
> -		      __func__, bd->props.power, bd->props.fb_blank);
> +	fbtft_par_dbg(DEBUG_BACKLIGHT, par, "%s: blank=%d\n", __func__,
> blank); 
> -	on = !backlight_is_blank(bd);
>  	/* Onboard backlight connected to GPIO0 on SSD1351, GPIO1 unused */
> -	write_reg(par, 0xB5, on ? 0x03 : 0x02);
> +	write_reg(par, 0xB5, !blank ? 0x03 : 0x02);
>  
>  	return 0;
>  }
> 
> -- 
> 2.34.1

For debugging purposes here, would there be any point in logging props.state?
As in

        fbtft_par_dbg(DEBUG_BACKLIGHT, par,
-                     "%s: power=%d, fb_blank=%d\n",
-                     __func__, bd->props.power, bd->props.fb_blank);
+                     "%s: power=%d, state=%u\n",
+                     __func__, bd->props.power, bd->props.state);

In any case,

Reviewed-by: Stephen Kitt <steve@....org>

Regards,

Stephen

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