Thread (23 messages) 23 messages, 3 authors, 2018-07-27

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

From: Krzysztof Kozlowski <krzk@kernel.org>
Date: 2018-07-18 06:17:55
Also in: linux-arm-kernel, linux-pm, linux-samsung-soc, lkml

On 17 July 2018 at 22:23, Anand Moon [off-list ref] wrote:
Hi Krzysztof

On 17 July 2018 at 17:50, Krzysztof Kozlowski [off-list ref] wrote:
quoted
Hi Anand,

Thanks for patch.

On 17 July 2018 at 12:12, Anand Moon [off-list ref] wrote:
quoted
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.
I am sorry but I am still unable to see what is broken and what are
you trying to fix. I asked what is broken and you replied that there
is a sensor, there is a clock, drivers use clk_prepare_enable and some
more parameter need to be tuned... None of these are answers to
question - what is broken. How can I reproduce the problem?

Best regards,
Krzysztof
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