From mboxrd@z Thu Jan 1 00:00:00 1970 From: robh@kernel.org (Rob Herring) Date: Mon, 11 Apr 2016 10:40:13 -0500 Subject: [PATCH v8 02/20] PM / devfreq: exynos: Add documentation for generic exynos bus frequency driver In-Reply-To: <1460089509-16260-3-git-send-email-cw00.choi@samsung.com> References: <1460089509-16260-1-git-send-email-cw00.choi@samsung.com> <1460089509-16260-3-git-send-email-cw00.choi@samsung.com> Message-ID: <20160411154012.GA24665@rob-hp-laptop> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 > Reviewed-by: Krzysztof Kozlowski > Signed-off-by: MyungJoo Ham > --- > .../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