Subject: [PATCH 3/5] clk: samsung: Document binding for Exynos4415 clock controller

From: [email-masked] (Chanwoo Choi)
Date: Fri, 24 Oct 2014 19:34:54 +0900

Hi Sylwester,

On 10/24/2014 07:32 PM, Sylwester Nawrocki wrote:
> On 20/10/14 05:32, Chanwoo Choi wrote:
>> The Exynos4415 clocks are statically listed and registered using the
>> Samsung specific common clock helper functions. Both device tree based
>> clock lookup and clkdev based clock lookups are supported.
> 
> I think the above text is not relevant, DT binding is not supposed
> to depend on any OS. Instead I would just put here something like:
> 
> "This patch adds DT binding documentation for Exynos4415 SoC system
> clock controllers."

OK, I will modify it as your comment.

> 
>> Cc: Sylwester Nawrocki <[email-masked]>
>> Cc: Tomasz Figa <[email-masked]>
>> Signed-off-by: Chanwoo Choi <[email-masked]>
>> Acked-by: Kyungmin Park <[email-masked]>
>> ---
>>  .../devicetree/bindings/clock/exynos4415-clock.txt | 49 ++++++++++++++++++++++
>>  1 file changed, 49 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/clock/exynos4415-clock.txt
>>
>> diff --git a/Documentation/devicetree/bindings/clock/exynos4415-clock.txt b/Documentation/devicetree/bindings/clock/exynos4415-clock.txt
>> new file mode 100644
>> index 0000000..8aa4f4f
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/clock/exynos4415-clock.txt
>> @@ -0,0 +1,49 @@
>> +* Samsung Exynos4415 Clock Controller
>> +
>> +The Exynos4415 clock controller generates and supplies clock to various
>> +controllers within the Exynos4415 SoC.
> 
> s/controllers/consumer devices/ ?
> 
>> +
>> +Required Properties:
> 
> s/P/p/ ?

I'll fix it.

> 
>> +
>> +- compatible: should be one of the following.
> 
> s/./:/ ?

I will change it (. -> :)

> 
>> +  - "samsung,exynos4415-cmu" - controller compatible with Exynos4415 SoC.
> 
>>>From current description it seems "samsung,exynos4415-cmu-dmc" is compatible
> with "samsung,exynos4415-cmu", which is not the case AFAIK.
> Perhaps we should change description here to something along the lines of:
> 
> - "samsung,exynos4415-cmu" - for the main system clocks controller
>   (CMU_LEFTBUS, CMU_RIGHTBUS, CMU_TOP, CMU_CPU clock domains),
> 
>> +  - "samsung,exynos4415-cmu-dmc" - controller compatible with
>> +    Exynos4415 SoC for Dynamic Memory Controller domain.
> 
> This seems unclear, how about
> 
>  - "samsung,exynos4415-cmu-dmc" - for the Exynos4415 SoC DRAM Memory
>     Controller (DMC) domain clock controller.
> 
> ?

OK, I'll modify it

>> +- reg: physical base address of the controller and length of memory mapped
>> +  region.
>> +
>> +- #clock-cells: should be 1.
>> +
>> +Each clock is assigned an identifier and client nodes can use this identifier
>> +to specify the clock which they consume.
>> +
>> +All available clocks are defined as preprocessor macros in
>> +dt-bindings/clock/exynos4415.h header and can be used in device
>> +tree sources.
> 
>> +Example 1: An example of a clock controller node is listed below.
>> +
>> +	cmu: clock-controller at 10030000 {
>> +		compatible = "samsung,exynos4415-cmu";
>> +		reg = <0x10030000 0x18000>;
>> +		#clock-cells = <1>;
>> +	};
>> +
>> +	cmu-dmc: clock-controller at 105C0000 {
>> +		compatible = "samsung,exynos4415-cmu-dmc";
>> +		reg = <0x105C0000 0x3000>;
>> +		#clock-cells = <1>;
>> +	};
>> +
>> +Example 2: UART controller node that consumes the clock generated by the clock
>> +	   controller. Refer to the standard clock bindings for information
>> +	   about 'clocks' and 'clock-names' property.
>> +
>> +	serial_0: serial at 13800000 {
>> +		compatible = "samsung,exynos4210-uart";
>> +		reg = <0x13800000 0x100>;
>> +		interrupts = <0 109 0>;
>> +		clocks = <&cmu CLK_UART0>, <&cmu CLK_SCLK_UART0>;
>> +		clock-names = "uart", "clk_uart_baud0";
>> +	};
> 
> I think we could omit those example snippets, it's all generic stuff and
> there is already plenty examples in descriptions of the DT binding for
> other SoCs.

OK, I'll drop this example.

Thanks for your review.

Best Regards,
Chanwoo Choi

> --
> Regards,
> Sylwester