linux-kernel - Re: [PATCH v2] auxdisplay: ht16k33: Use backlight helper

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Date:   Mon, 09 Jan 2023 10:51:06 +0100
From:   Robin van der Gracht <robin@...tonic.nl>
To:     Stephen Kitt <steve@....org>
Cc:     Miguel Ojeda <ojeda@...nel.org>, linux-kernel@...r.kernel.org,
        Sam Ravnborg <sam@...nborg.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH v2] auxdisplay: ht16k33: Use backlight helper

On 2023-01-06 15:30, Stephen Kitt wrote:
> backlight_properties.fb_blank is deprecated. The states it represents
> are handled by other properties; but instead of accessing those
> properties directly, drivers should use the helpers provided by
> backlight.h.
> 
> Instead of retrieving the backlight brightness in struct
> backlight_properties manually, and then checking whether the backlight
> should be on at all, use backlight_get_brightness() which does all
> this and insulates this from future changes.
> 
> This means that BL_CORE_SUSPENDED is now taken into account, as it
> should be.
> 
> Signed-off-by: Stephen Kitt <steve@....org>
> ---
> 
> Notes:
>     Changes since v1: mention BL_CORE_SUSPENDED.
> 
>  drivers/auxdisplay/ht16k33.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/drivers/auxdisplay/ht16k33.c 
> b/drivers/auxdisplay/ht16k33.c
> index 02425991c159..15ab118c80f5 100644
> --- a/drivers/auxdisplay/ht16k33.c
> +++ b/drivers/auxdisplay/ht16k33.c
> @@ -314,14 +314,9 @@ static int ht16k33_initialize(struct ht16k33_priv 
> *priv)
> 
>  static int ht16k33_bl_update_status(struct backlight_device *bl)
>  {
> -	int brightness = bl->props.brightness;
> +	int brightness = backlight_get_brightness(bl);
>  	struct ht16k33_priv *priv = bl_get_data(bl);
> 
> -	if (bl->props.power != FB_BLANK_UNBLANK ||
> -	    bl->props.fb_blank != FB_BLANK_UNBLANK ||
> -	    bl->props.state & BL_CORE_FBBLANK)
> -		brightness = 0;
> -
>  	return ht16k33_brightness_set(priv, brightness);
>  }

Thank you Stephen (and Sam), looks good!

Reviewed-by: Robin van der Gracht <robin@...tonic.nl>