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From: Krzysztof Kozlowski <krzk@kernel.org>
To: Sylwester Nawrocki <snawrocki@kernel.org>
Cc: Tomasz Figa <tomasz.figa@gmail.com>,
	linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Sylwester Nawrocki <s.nawrocki@samsung.com>,
	Chanwoo Choi <cw00.choi@samsung.com>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>, Kukjin Kim <kgene@kernel.org>,
	linux-samsung-soc@vger.kernel.org,
	Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: [PATCH 1/2] soc: samsung: exynos-pmu: instantiate clkout driver as MFD
Date: Fri, 23 Oct 2020 13:37:28 +0200	[thread overview]
Message-ID: <20201023113728.GA61748@kozik-lap> (raw)
In-Reply-To: <32d3faaf-1631-3ebe-6d73-fe565c39639d@kernel.org>

On Fri, Oct 23, 2020 at 01:34:19PM +0200, Sylwester Nawrocki wrote:
> Hi,
> 
> On 10/1/20 18:56, Krzysztof Kozlowski wrote:
> > The Exynos clock output (clkout) driver uses same register address space
> > (Power Management Unit address space) as Exynos PMU driver and same set
> > of compatibles.  It was modeled as clock provider instantiated with
> > CLK_OF_DECLARE_DRIVE().
> > 
> > This however brings ordering problems and lack of probe deferral,
> > therefore clkout driver should be converted to a regular module and
> > instantiated as a child of PMU driver to be able to use existing
> > compatibles and address space.
> 
> It might have been cleaner to have the CLKOUT device as a PMU subnode in DT, 
> then device instantiation would be already covered by devm_of_platform_populate().
> But it gets a bit complicated to make such a change in a backward compatible way.

Yes, I agree, but the backward compatibility would be here a pain.
Optionally the driver could check for new DTB and skip adding MFD
children... but this is just simpler.

> 
> I have tested both patches on Trats2, where CLKOUT provides master clock for
> the audio codec.
> 
> Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> Tested-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

Thanks!

Best regards,
Krzysztof

WARNING: multiple messages have this Message-ID (diff)
From: Krzysztof Kozlowski <krzk@kernel.org>
To: Sylwester Nawrocki <snawrocki@kernel.org>
Cc: linux-samsung-soc@vger.kernel.org,
	Stephen Boyd <sboyd@kernel.org>,
	Michael Turquette <mturquette@baylibre.com>,
	linux-kernel@vger.kernel.org, Tomasz Figa <tomasz.figa@gmail.com>,
	Chanwoo Choi <cw00.choi@samsung.com>,
	Kukjin Kim <kgene@kernel.org>,
	Sylwester Nawrocki <s.nawrocki@samsung.com>,
	linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: [PATCH 1/2] soc: samsung: exynos-pmu: instantiate clkout driver as MFD
Date: Fri, 23 Oct 2020 13:37:28 +0200	[thread overview]
Message-ID: <20201023113728.GA61748@kozik-lap> (raw)
In-Reply-To: <32d3faaf-1631-3ebe-6d73-fe565c39639d@kernel.org>

On Fri, Oct 23, 2020 at 01:34:19PM +0200, Sylwester Nawrocki wrote:
> Hi,
> 
> On 10/1/20 18:56, Krzysztof Kozlowski wrote:
> > The Exynos clock output (clkout) driver uses same register address space
> > (Power Management Unit address space) as Exynos PMU driver and same set
> > of compatibles.  It was modeled as clock provider instantiated with
> > CLK_OF_DECLARE_DRIVE().
> > 
> > This however brings ordering problems and lack of probe deferral,
> > therefore clkout driver should be converted to a regular module and
> > instantiated as a child of PMU driver to be able to use existing
> > compatibles and address space.
> 
> It might have been cleaner to have the CLKOUT device as a PMU subnode in DT, 
> then device instantiation would be already covered by devm_of_platform_populate().
> But it gets a bit complicated to make such a change in a backward compatible way.

Yes, I agree, but the backward compatibility would be here a pain.
Optionally the driver could check for new DTB and skip adding MFD
children... but this is just simpler.

> 
> I have tested both patches on Trats2, where CLKOUT provides master clock for
> the audio codec.
> 
> Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> Tested-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

Thanks!

Best regards,
Krzysztof

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  reply	other threads:[~2020-10-23 11:37 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-01 16:56 [PATCH 0/2] samsung: exynos: convert clkout to module driver Krzysztof Kozlowski
2020-10-01 16:56 ` Krzysztof Kozlowski
2020-10-01 16:56 ` [PATCH 1/2] soc: samsung: exynos-pmu: instantiate clkout driver as MFD Krzysztof Kozlowski
2020-10-01 16:56   ` Krzysztof Kozlowski
2020-10-14  2:44   ` Stephen Boyd
2020-10-14  2:44     ` Stephen Boyd
2020-10-23 11:34   ` Sylwester Nawrocki
2020-10-23 11:34     ` Sylwester Nawrocki
2020-10-23 11:37     ` Krzysztof Kozlowski [this message]
2020-10-23 11:37       ` Krzysztof Kozlowski
2020-10-28 22:02   ` Krzysztof Kozlowski
2020-10-28 22:02     ` Krzysztof Kozlowski
2020-10-01 16:56 ` [PATCH 2/2] clk: samsung: exynos-clkout: convert to module driver Krzysztof Kozlowski
2020-10-01 16:56   ` Krzysztof Kozlowski
2020-10-14  2:43   ` Stephen Boyd
2020-10-14  2:43     ` Stephen Boyd
2020-10-14  6:17     ` Krzysztof Kozlowski
2020-10-14  6:17       ` Krzysztof Kozlowski
2020-10-23 11:42   ` Sylwester Nawrocki
2020-10-23 11:42     ` Sylwester Nawrocki
2020-10-28 22:07   ` Krzysztof Kozlowski
2020-10-28 22:07     ` Krzysztof Kozlowski

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