Re: [PATCH v1 21/50] ARM: dts: exynos: add OPP into FSYS APB bus in Exynos5420

From: Lukasz Luba
Date: Mon Jul 22 2019 - 06:47:11 EST


Hi Krzysztof,

On 7/17/19 10:48 AM, Krzysztof Kozlowski wrote:
> On Mon, 15 Jul 2019 at 14:44, Lukasz Luba <l.luba@xxxxxxxxxxxxxxxxxxx> wrote:
>>
>> Add an OPP for FSYS APB which reflects the real possible frequency.
>> The bus will have a new parent clock which speed has 600MHz, thus
>> a new possible frequency provided by the clock divider is 150MHz.
>> According to the documentation max possible frequency for this bus is
>> 200MHz.
>
> Commit msg is good but title could be improved. Focus in the title
> what problem/issue you are solving - add intermediate step in scaling
> of FSYS APB?
The devfreq governor for this bus device follows the set OPP of the
master device - WCORE bus and sets the OPP with corresponding ID.
Thus, jumping to max frequency 200MHz when the WCORE bus and other
devices are operating in the middle of their min-max speed is not
needed for FSYS APB and this patch adds the intermediate speed step.

Regards,
Lukasz

>
> Best regards,
> Krzysztof
>
>