Re: [PATCH 2/8] clk: tegra: host1x has fractional divider

From: Peter De Schrijver
Date: Mon Jul 23 2018 - 07:12:24 EST


On Mon, Jul 23, 2018 at 10:32:58AM +0100, Ben Dooks wrote:
>
>
> On 2018-07-23 09:50, Peter De Schrijver wrote:
> >On Fri, Jul 20, 2018 at 02:45:26PM +0100, Ben Dooks wrote:
> >>The host1x clock according to both tegra2 and tegra3 manuals is
> >>an 8bit divider with lsb being fractional. This is running into
> >>an issue where the host1x is being set on a tegra20a system to
> >>266.4MHz but ends up at 222MHz instead.
> >>
> >
> >The fact the hw has a fractional divider, does not mean we're
> >allowed to use
> >it. Due to the non 50% duty cycle of fractional divided clocks,
> >they are not
> >allowed for certain peripherals. Do you have information
> >indicating this is
> >ok for the host1x clock?
>
> Only that's what was setup for the systems we're using.
> We couldn't match the 2.6 working system without these changes.
>

On Tegra20 or Tegra30?

Peter.