Re: [PATCH v4 02/20] PM / devfreq: exynos: Add documentation for generic exynos bus frequency driver
From: MyungJoo Ham
Date: Mon Dec 14 2015 - 03:40:12 EST
>
> This patch adds the documentation for generic exynos bus frequency
> driver.
>
> Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
A little changes following:
> ---
> .../devicetree/bindings/devfreq/exynos-bus.txt | 93 ++++++++++++++++++++++
> 1 file changed, 93 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..e32daef328da
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
> @@ -0,0 +1,93 @@
> +* Generic Exynos Bus frequency device
> +
> +The Samsung Exynos SoC have many buses for data transfer between DRAM
+The Samsung Exynos SoC has many buses for data transfer between DRAM
or
+The Samsung Exynos SoCs have many buses for data transfer between DRAM
(because you intend to support mulitple Exynos SoCs)
> +and sub-blocks in SoC. Almost Exynos SoC have the common architecture
+and sub-blocks in SoC. Most Exynos SoCs share the common architecture
> +for buses. Generally, the each bus of Exynos SoC includes the source clock
+for buses. Generally, each bus of Exynos SoC includes a source clock
> +and power line and then is able to change the clock according to the usage
+and a power line, which are able to change the clock frequency
> +of each buses on runtime. When gathering the usage of each buses on runtime,
+of the bus in runtime. To monitor the usage of each bus in runtime,
> +the driver uses the PPMU (Platform Performance Monitoring Unit) which
+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 the different sub-blocks. So, this difference should be specified
+SoC has different sub-blocks. Therefore, such 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.
> +
[]
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