Subject: [PATCH 00/11] ARM: OMAP: OMAP5 & AM43x DSS

From: [email-masked] (Archit Taneja)
Date: Tue, 20 May 2014 11:01:19 +0530

Hi,

On Friday 16 May 2014 01:44 PM, Tomi Valkeinen wrote:
> On 12/05/14 18:48, Tony Lindgren wrote:
>
>>>> Also, I'm wondering why we still have .clk and .opt_clks entries in the
>>>> hwmod data for am43xx and omap5 which are both device tree based with
>>>> all the clocks coming from .dts files?
>>>
>>> I think they are needed for the omap_device/hwmod stuff to work. Only
>>> omapdss driver knows about the clocks defined in the .dts files, and the
>>> omap_device/hwmod code still needs to do the reset and maybe some other
>>> tasks that require the clocks.
>>
>> We're already populating the hwmod data from dts entries, that's done by
>> omap_device_build_from_dt. Why aren't we doing that for dt defined clocks?
>>
>> I'd rather not start adding new data that will then just be removed, that's
>> what people call "pointless extra churn".
>
> I don't know why. I have to say I'm not 100% sure if that's done or not,
> but at least I can't find where it's done.

The reason why clocks are needed from hwmod data is because we still 
don't populate hwmod fields like main_clk and opt_clock from DT clocks.

The reason why this isn't done yet is because we currently haven't 
figured out a clean way to tell hwmod what clock is the main_clk, and 
what clocks are optional clocks.

One of the proposed methods was to assume the clock named to be "fck" as 
main_clk, and the remaining clocks as optional clocks for hwmod. That 
method wasn't agreed upon, this looks like the thread which discusses this:

http://marc.info/?l=linux-arm-kernel&m=138928084823142&w=2

Archit