[U-Boot] [PATCH 3/3] pwm: sunxi: choose best prescaler to improve PWM resolution

[Vasily Khoruzhick]

On Mon, Oct 22, 2018 at 11:29 AM Jagan Teki <jagan at amarulasolutions.com> wrote:
>
> On Wed, Oct 17, 2018 at 10:28 AM Vasily Khoruzhick <anarsoul at gmail.com> wrote:
> >
> > Choose best prescaler to improve PWM resolution. Without this change
> > driver chooses first prescaler that gives us period value within
> > range, but it could be not the best one.
>
> This commit need to elaborate about the real issue, ie got fixed.
> Understand it has chosen best prescaler but why and how it.

If PWM resolution is low then close backlight levels can result in the
same PWM settings, i.e. 0% and 10% can be the same (and thus backlight
remains powered off). Basically the patch does what comment says - it
improves PWM resolution.