RE: [PATCH v6 4/4] clk: samsung: add top clock support for ExynosAuto v920 SoC

["sunyeal.hong" <sunyeal.hong@samsung.com>]

Hello Krzysztof,

> -----Original Message-----
> From: Krzysztof Kozlowski <krzk@kernel.org>
> Sent: Wednesday, August 21, 2024 5:02 PM
> To: sunyeal.hong <sunyeal.hong@samsung.com>; 'Kwanghoon Son'
> <k.son@samsung.com>; 'Sylwester Nawrocki' <s.nawrocki@samsung.com>;
> 'Chanwoo Choi' <cw00.choi@samsung.com>; 'Alim Akhtar'
> <alim.akhtar@samsung.com>; 'Michael Turquette' <mturquette@baylibre.com>;
> 'Stephen Boyd' <sboyd@kernel.org>; 'Rob Herring' <robh@kernel.org>; 'Conor
> Dooley' <conor+dt@kernel.org>
> Cc: linux-samsung-soc@vger.kernel.org; linux-clk@vger.kernel.org;
> devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH v6 4/4] clk: samsung: add top clock support for
> ExynosAuto v920 SoC
> 
> On 21/08/2024 09:06, sunyeal.hong wrote:
> >>>>>>> +	.clk_name		= "dout_clkcmu_peric0_noc",
> >>>>>>
> >>>>>> same question.
> >>>>>> Isn't it "noc"?
> >>>>>> https://lore.kernel.org/linux-samsung-
> >>>>>> soc/58dfae564a4a624e464c7803a309f1f07b5ae83d.camel@samsung.com/
> >>>>>>
> >>>>>> In my case(autov9), if put wrong clk_name dmesg will show that,
> >>>>>> exynos_arm64_register_cmu: could not enable bus clock ...; err =
> >>>>>> -2
> >>>>>>
> >>>>>> Kwang.
> >>>>>>
> >>>>>>
> >>>>>
> >>>>> clk_name follows the guide document provided by hw. v9 is bus, but
> >>>>> v920
> >>>> uses noc.
> >>>>
> >>>> What I mean,
> >>>>
> >>>> .clk_name		= "dout_clkcmu_peric0_noc", // wrong
> >>>> .clk_name		= "noc", // correct
> >>>>
> >>>> Because there is no clock-names "dout_clkcmu_peric0_noc" in
> >>>> exynos/exynosautov920.dtsi.
> >>>>
> >>>
> >>> The clk_name written here has nothing to do with the device tree.
> >>> Please
> >> look at the code carefully.
> >>
> >> Hm? I see in the code clearly:
> >>
> >> 	clk_get(dev, cmu->clk_name);
> >>
> >> Where cmu is the discussed struct.
> >>
> >> If you claim it does not have anything to do with DT, then what is it
> for?
> >>
> >> Best regards,
> >> Krzysztof
> >
> > In general, clk_get is used via the clk_name declared in the DT.
> >
> > However, the question asked here is the parent clock name of peric0_noc,
> so it is unrelated to the device tree.
> 
> No. The question was about clk_name entry in cmu info used directly for
> clk_get.
> 

I have verified that peric0 has a dev parameter and that it should use a clk_name that matches the clock-names declared in the device tree. I will update the patch with a fix.

Best Regards,
sunyeal

> 
> Best regards,
> Krzysztof
>