Re: [PATCH] drm/omap: Migrate minimum FCK/PCK ratio from Kconfig to dts
From: H. Nikolaus Schaller
Date: Mon Sep 30 2019 - 10:56:57 EST
> Am 30.09.2019 um 16:27 schrieb Tomi Valkeinen <tomi.valkeinen@xxxxxx>:
>
> On 30/09/2019 17:20, Tomi Valkeinen wrote:
>
>> Let's see what Tero says, but yeah, something is odd here. I expected the max divider to be 16 with Tero's patch, but I don't see it having that effect. I can get the div to 31.
>> You can see this from the clock register 0x48004e40 (CM_CLKSEL_DSS). The lowest bits are the divider, 5 to 0. The TRM says max div is 32.
>> Tero said for him the dividers > 16 didn't "stick" to the register. I'm now wondering if he has an old beagleboard with OMAP34xx, which has max div 16.
>
> So testing a bit more here, I can see the DSS working fine and fps as expected when I write values directly to CM_CLKSEL_DSS:5:0, with dividers up to 31. With 32, DSS breaks. The TRM (AM/DM37x) says value 32 is valid.
Just a blind guess: is there something in the errata to take care of?