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

From: Ben Dooks
Date: Mon Jul 23 2018 - 07:32:11 EST




On 2018-07-23 12:12, Peter De Schrijver wrote:
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?

I'll check tomorrow when I have access to all the hw involved.

--
Ben