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Message-ID: <20160411154012.GA24665@rob-hp-laptop>
Date: Mon, 11 Apr 2016 10:40:13 -0500
From: Rob Herring <robh@...nel.org>
To: Chanwoo Choi <cw00.choi@...sung.com>
Cc: myungjoo.ham@...sung.com, kyungmin.park@...sung.com,
k.kozlowski@...sung.com, kgene@...nel.org, rjw@...ysocki.net,
pawel.moll@....com, mark.rutland@....com,
ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
linux@....linux.org.uk, linux.amoon@...il.com,
m.reichl@...etechno.de, tjakobi@...h.uni-bielefeld.de,
inki.dae@...sung.com, linux-kernel@...r.kernel.org,
linux-pm@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v8 02/20] PM / devfreq: exynos: Add documentation for
generic exynos bus frequency driver
On Fri, Apr 08, 2016 at 01:24:51PM +0900, Chanwoo Choi wrote:
> This patch adds the documentation for generic exynos bus frequency
> driver.
>
> Signed-off-by: Chanwoo Choi <cw00.choi@...sung.com>
> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
> Signed-off-by: MyungJoo Ham <myungjoo.ham@...sung.com>
> ---
> .../devicetree/bindings/devfreq/exynos-bus.txt | 95 ++++++++++++++++++++++
> 1 file changed, 95 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/devfreq/exynos-bus.txt
>
> diff --git a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> new file mode 100644
> index 000000000000..78171b918e3f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> @@ -0,0 +1,95 @@
> +* Generic Exynos Bus frequency device
> +
> +The Samsung Exynos SoC has many buses for data transfer between DRAM
> +and sub-blocks in SoC. Most Exynos SoCs share the common architecture
> +for buses. Generally, each bus of Exynos SoC includes a source clock
> +and a power line, which are able to change the clock frequency
> +of the bus in runtime. To monitor the usage of each bus in runtime,
> +the driver uses the PPMU (Platform Performance Monitoring Unit), which
> +is able to measure the current load of sub-blocks.
> +
> +There are a little different composition among Exynos SoC because each Exynos
> +SoC has different sub-blocks. Therefore, shch difference should be specified
> +in devicetree file instead of each device driver. In result, this driver
> +is able to support the bus frequency for all Exynos SoCs.
I still have issues with this whole series. The DT hierarchy represents
buses. You are describing buses here and control of them. I would expect
to see some hierarchy, but there is none. What this looks like is you
are adding nodes based on what fits the current driver.
Rob
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