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

[Tomi Valkeinen <tomi.valkeinen@ti.com>]

On 20/04/2020 18:55, Daniel Thompson wrote:
> 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@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?

Indeed, better to set it to max.

  Tomi

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