Re: [PATCH 1/5] thermal: exynos: enable core tmu clk on exynos platform

From: Anand Moon
Date: Tue Jul 17 2018 - 16:24:23 EST


Hi Krzysztof

On 17 July 2018 at 17:50, Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> Hi Anand,
>
> Thanks for patch.
>
> On 17 July 2018 at 12:12, Anand Moon <linux.amoon@xxxxxxxxx> wrote:
>> clk_summary do not show tmu_apbif clk enable, so replace
>> the clk_prepare with clk_prepare_enables to enable tmu clk.
>
> This is not valid reason to do a change. What is clk_summary does not
> really matter. Your change has negative impact on power consumption as
> the clock stays enabled all the time. This is not what we want... so
> please explain it more - why you need the clock to be enabled all the
> time? What is broken (clk_summary is not broken in this case)?
>

Opps I could not explain some more in my commit message.

Actually TMU sensor for Exynos process are controlled by so external clk

Exynos4412 have VDD18_TS sensor which controls the CLK_SENSE tmu.
Exynos5422 have VDD18_TS01 / VDD18_TS23 / VDD18_TS4 sensor which
control the CLK_SENSE tmu.

So as per my understanding tmu is clk driver which control the flow PMIC.

clk_prepare_enable combine clk_prepare and clk_enable
and clk_disable_unprepare combine clk_disable and clk_unprepare.

most of the driver prefer clk_prepare_enable and clk_disable_unprepare.

clk_summary is just a reference looking point where we could check the
clk is enable/disable.

what is broken ?
I still few more parameter need to tuned to configure the tmu driver.

>> simplify the enable of tmu_triminfo_apbif clk, also fixed
>> the order of goto error for failed cases.
>
> This has to be split into separate change.
>
> Best regards,
> Krzysztof

Best Regards
-Anand