From mboxrd@z Thu Jan  1 00:00:00 1970
From: Vasily Khoruzhick <anarsoul@gmail.com>
Date: Mon, 22 Oct 2018 11:35:58 -0700
Subject: [U-Boot] [PATCH 3/3] pwm: sunxi: choose best prescaler to
 improve PWM resolution
In-Reply-To: <CAMty3ZA+fH3So1W6QKMA4e4+gRrX5rWAnP3vvU=FirWrXJJByQ@mail.gmail.com>
References: <20181017045635.9857-1-anarsoul@gmail.com>
 <20181017045635.9857-3-anarsoul@gmail.com>
 <CAMty3ZA+fH3So1W6QKMA4e4+gRrX5rWAnP3vvU=FirWrXJJByQ@mail.gmail.com>
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On Mon, Oct 22, 2018 at 11:29 AM Jagan Teki <jagan@amarulasolutions.com> wrote:
>
> On Wed, Oct 17, 2018 at 10:28 AM Vasily Khoruzhick <anarsoul@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.