Re: [PATCH] clk: Hi6220: enable stub clock driver for ARCH_HISI

[Amit Kucheria]

On Mon, Aug 8, 2016 at 12:12 PM, Leo Yan <leo.yan@xxxxxxxxxx> wrote:
> Hi Amit,
>
> On Mon, Aug 08, 2016 at 11:23:31AM +0530, Amit Kucheria wrote:
>> On Mon, Aug 8, 2016 at 9:07 AM, Leo Yan <leo.yan@xxxxxxxxxx> wrote:
>> > In current kernel config 'CONFIG_STUB_CLK_HI6220' is disabled by
>> > default, as result stub clock driver has not been registered and
>> > CPUFreq driver cannot work.
>>
>> I have a related patch that has been pending for a while:
>> https://lkml.org/lkml/2016/6/20/375 but it was tied only to the
>> thermal driver.
>
> I also have concern this patch may duplicate with yours.
>
>> Is the stub mandatory for the architecture? Will other SoCs in the
>> family will use the same stub?
>
> I don't think stub driver is mandartory for archtitecture and it's
> only used by Hi6220 on Hikey. AFAIK, currently stub driver is only used
> by CPU frequency change.
>
> The logic is:
>   Thermal cooling device driver
>       `-> CPUFreq DT driver
>               `-> Stub clock driver
>
> ARM is working on Hikey for EAS profiling, so usually the use case is
> to enable CPUFreq driver and stub clock driver. Sometimes it only
> need enable this driver without thermal driver; so this is why we
> cannot rely on thermal driver to enable stub clock driver.
>
> I'm open-minded if you have better idea to enable it.
>
>> > This patch is to enable stub clock driver in config for ARCH_HISI.
>> >
>> > Reported-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
>> > Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>
>> > ---
>> >  drivers/clk/hisilicon/Kconfig | 1 +
>> >  1 file changed, 1 insertion(+)
>> >
>> > diff --git a/drivers/clk/hisilicon/Kconfig b/drivers/clk/hisilicon/Kconfig
>> > index 3f537a0..9e0a95e 100644
>> > --- a/drivers/clk/hisilicon/Kconfig
>> > +++ b/drivers/clk/hisilicon/Kconfig
>> > @@ -23,5 +23,6 @@ config RESET_HISI
>> >  config STUB_CLK_HI6220
>> >         bool "Hi6220 Stub Clock Driver"
>> >         depends on COMMON_CLK_HI6220 && MAILBOX
>> > +       default ARCH_HISI

Instead of forcing this up on the entire arch, why not restrict it to
just the cpufreq driver?  ARM_HISI_ACPU_CPUFREQ?

>> >         help
>> >           Build the Hisilicon Hi6220 stub clock driver.
>> > --
>> > 1.9.1
>> >