Re: [RFC PATCH v3 1/2] clk: samsung: Add a clock lookup function

[Javier Martinez Canillas]

+Tomeu who I forgot to add to the cc list.

Hello Mike,

Thanks a lot for your feedback.

On 03/31/2015 03:40 AM, Michael Turquette wrote:
>> 
>> I don't performance is a big issue here. I just thought that since the
>> lookup table is already filled by the driver and the lookup function
>> is one line, we could use that instead to get the performance benefit.
>> 
>> But I don't mind to drop this patch and use the generic lookup function
>> from the CCF API if that is preferred.
> 
> Hello,
> 
> I am not a fan of __clk_lookup and I don't like to see it used more and
> more outside of drivers/clk/clk.c. You mentioned that performance wasn't
> really the problem here.  The real method for a driver to get a clock is
> with clk_get(). Any reason to not use that?
>

I can certainly use clk_get() but I thought that the clk consumer API was
not supposed to be used from within clock drivers. That's why I mentioned
__clk_lookup() as a possibility since that is part of the provider API.

Below is a RFC patch that uses clk_get() [0]. That needs another patch
which was part of a previous RFC and adds an alias for the mdma0 clock:

https://lkml.org/lkml/2015/3/27/769

If you think that is the correct approach then I can post it as a patch.

It would be great if you can also provide some feedback about the other
patch in the first RFC that instead of enabling and disabling the mdma0
clock in driver, does it in the exynos5420 platform PM callbacks:

https://lkml.org/lkml/2015/3/27/770

I was asked to do it in the exynos5420 clk driver instead but maybe you
have a different opinion on that.

Best regards,
Javier

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