[PATCH 4/5] backlight: led_bl: fix led -> backlight brightness mapping

[Daniel Thompson]

On Fri, Apr 17, 2020 at 02:33:11PM +0300, Tomi Valkeinen wrote:
> The code that maps the LED default brightness to backlight levels has
> two issues: 1) if the default brightness is the first backlight level
> (usually 0), the code fails to find it, and 2) when the code fails to
> find a backlight level, it ends up using max_brightness + 1 as the
> default brightness.
> 
> Fix these two issues.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
> ---
>  drivers/video/backlight/led_bl.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/video/backlight/led_bl.c b/drivers/video/backlight/led_bl.c
> index 63693c4f0883..021b5edd895c 100644
> --- a/drivers/video/backlight/led_bl.c
> +++ b/drivers/video/backlight/led_bl.c
> @@ -159,10 +159,11 @@ static int led_bl_parse_levels(struct device *dev,
>  		 */
>  		db = priv->default_brightness;
>  		for (i = 0 ; i < num_levels; i++) {
> -			if ((i && db > levels[i - 1]) && db <= levels[i])
> +			if ((i == 0 || db > levels[i - 1]) && db <= levels[i])
>  				break;
>  		}
> -		priv->default_brightness = i;
> +
> +		priv->default_brightness = i < num_levels ? i : 0;

This seems a bit odd. If the LED is currently set to brighter than the
maximum brightness level why would we choose a default brightness of
zero?


Daniel.


>  		priv->max_brightness = num_levels - 1;
>  		priv->levels = levels;
>  	} else if (num_levels >= 0) {
> -- 
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