On Wed, Jun 08, 2022 at 10:56:23PM +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.
Then brightness can only be negative if the backlight is on but props.brightness is negative, so the test before reading the brightness value from the hardware can be simplified to (brightness < 0).
props.brightness should always be in the interval 0..max_brightness.
This is enforced by the main backlight code (and APIs to set the brightness use unsigned values). Thus props.brightness could only be negative is the driver explicitly sets a negative value as some kind of placeholder (which this driver does not do).
I don't think there is any need to keep this logic.
Daniel.
diff --git a/drivers/video/fbdev/atmel_lcdfb.c b/drivers/video/fbdev/atmel_lcdfb.c index 1fc8de4ecbeb..06159a4da293 100644 --- a/drivers/video/fbdev/atmel_lcdfb.c +++ b/drivers/video/fbdev/atmel_lcdfb.c @@ -109,22 +108,10 @@ 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 = backlight_get_brightness(bl);
- /* 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)
- if (brightness < 0) brightness = lcdc_readl(sinfo, ATMEL_LCDC_CONTRAST_VAL);
else if (power != FB_BLANK_UNBLANK)
brightness = 0;lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_VAL, brightness); if (contrast_ctr & ATMEL_LCDC_POL_POSITIVE)