Re: [PATCH v2 5/8] dt-bindings: clock: samsung: convert Exynos4 to dtschema

[Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>]

On 17/08/2021 22:24, Rob Herring wrote:
> On Tue, Aug 10, 2021 at 11:31:42AM +0200, Krzysztof Kozlowski wrote:
>> Merge Exynos4210 and Exynos4412 clock controller bindings to existing DT
>> schema.
>>
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
>> ---
>>  .../bindings/clock/exynos4-clock.txt          | 86 -------------------
>>  .../bindings/clock/samsung,exynos-clock.yaml  | 29 ++++++-
>>  2 files changed, 28 insertions(+), 87 deletions(-)
>>  delete mode 100644 Documentation/devicetree/bindings/clock/exynos4-clock.txt
>>
>> diff --git a/Documentation/devicetree/bindings/clock/exynos4-clock.txt b/Documentation/devicetree/bindings/clock/exynos4-clock.txt
>> deleted file mode 100644
>> index 17bb11365354..000000000000
>> --- a/Documentation/devicetree/bindings/clock/exynos4-clock.txt
>> +++ /dev/null
>> @@ -1,86 +0,0 @@
>> -* Samsung Exynos4 Clock Controller
>> -
>> -The Exynos4 clock controller generates and supplies clock to various controllers
>> -within the Exynos4 SoC. The clock binding described here is applicable to all
>> -SoC's in the Exynos4 family.
>> -
>> -Required Properties:
>> -
>> -- compatible: should be one of the following.
>> -  - "samsung,exynos4210-clock" - controller compatible with Exynos4210 SoC.
>> -  - "samsung,exynos4412-clock" - controller compatible with Exynos4412 SoC.
>> -
>> -- 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/exynos4.h header and can be used in device
>> -tree sources.
>> -
>> -Example 1: An example of a clock controller node is listed below.
>> -
>> -	clock: clock-controller@10030000 {
>> -		compatible = "samsung,exynos4210-clock";
>> -		reg = <0x10030000 0x20000>;
>> -		#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@13820000 {
>> -		compatible = "samsung,exynos4210-uart";
>> -		reg = <0x13820000 0x100>;
>> -		interrupts = <0 54 0>;
>> -		clocks = <&clock CLK_UART2>, <&clock CLK_SCLK_UART2>;
>> -		clock-names = "uart", "clk_uart_baud0";
>> -	};
>> -
>> -Exynos4412 SoC contains some additional clocks for FIMC-ISP (Camera ISP)
>> -subsystem. Registers for those clocks are located in the ISP power domain.
>> -Because those registers are also located in a different memory region than
>> -the main clock controller, a separate clock controller has to be defined for
>> -handling them.
>> -
>> -Required Properties:
>> -
>> -- compatible: should be "samsung,exynos4412-isp-clock".
>> -
>> -- reg: physical base address of the ISP clock controller and length of memory
>> -  mapped region.
>> -
>> -- #clock-cells: should be 1.
>> -
>> -- clocks: list of the clock controller input clock identifiers,
>> -  from common clock bindings, should point to CLK_ACLK200 and
>> -  CLK_ACLK400_MCUISP clocks from the main clock controller.
>> -
>> -- clock-names: list of the clock controller input clock names,
>> -  as described in clock-bindings.txt, should be "aclk200" and
>> -  "aclk400_mcuisp".
>> -
>> -- power-domains: a phandle to ISP power domain node as described by
>> -  generic PM domain bindings.
>> -
>> -Example 3: The clock controllers bindings for Exynos4412 SoCs.
>> -
>> -	clock: clock-controller@10030000 {
>> -		compatible = "samsung,exynos4412-clock";
>> -		reg = <0x10030000 0x18000>;
>> -		#clock-cells = <1>;
>> -	};
>> -
>> -	isp_clock: clock-controller@10048000 {
>> -		compatible = "samsung,exynos4412-isp-clock";
>> -		reg = <0x10048000 0x1000>;
>> -		#clock-cells = <1>;
>> -		power-domains = <&pd_isp>;
>> -		clocks = <&clock CLK_ACLK200>, <&clock CLK_ACLK400_MCUISP>;
>> -		clock-names = "aclk200", "aclk400_mcuisp";
>> -	};
>> diff --git a/Documentation/devicetree/bindings/clock/samsung,exynos-clock.yaml b/Documentation/devicetree/bindings/clock/samsung,exynos-clock.yaml
>> index c7b07fcd3fa1..ea73201f259b 100644
>> --- a/Documentation/devicetree/bindings/clock/samsung,exynos-clock.yaml
>> +++ b/Documentation/devicetree/bindings/clock/samsung,exynos-clock.yaml
>> @@ -23,6 +23,9 @@ properties:
>>            - samsung,exynos3250-cmu
>>            - samsung,exynos3250-cmu-dmc
>>            - samsung,exynos3250-cmu-isp
>> +          - samsung,exynos4210-clock
>> +          - samsung,exynos4412-clock
>> +          - samsung,exynos4412-isp-clock
>>            - samsung,exynos5250-clock
>>            - samsung,exynos5420-clock
>>            - samsung,exynos5800-clock
>> @@ -35,11 +38,18 @@ properties:
>>    assigned-clocks: true
>>    assigned-clock-parents: true
>>    assigned-clock-rates: true
>> -  clocks: true
>> +  clocks:
>> +    description: |
>> +      For samsung,exynos4412-isp-clock, the input clocks should be CLK_ACLK200
>> +      and CLK_ACLK400_MCUISP from the main clock controller.
>> +
>> +  clock-names: true
>>  
>>    "#clock-cells":
>>      const: 1
>>  
>> +  power-domains: true
>> +
> 
> How many?

I'll add it.

> 
> Now all the flavors can have a power domain? Maybe this should be a 
> separate binding given this and the if/then below.

If you ask about the hardware specifically - almost all flavors could
have a power domain.

There are actually several clock controllers in every SoC responsible
for different parts (e.g. display, GPU, audio, video encoder) and most
of them could have a power domain.

However the clock controller bindings and drivers for all ARMv7 Exynos
SoCs were designed as one device with one device node. Inside the driver
spawns sub-controllers but still there is one device node.

Therefore the answer, if you ask about bindings and hardware-driver
model, is that only some of the flavors will have a power domain.

If you think that having to separate bindings, without that "allOf: if:"
below, is simpler then I can split it.

> 
>>    reg:
>>      maxItems: 1
>>  
>> @@ -50,6 +60,23 @@ required:
>>  
>>  additionalProperties: false
>>  
>> +allOf:
>> +  - if:
>> +      properties:
>> +        compatible:
>> +          contains:
>> +            const: samsung,exynos4412-isp-clock
>> +    then:
>> +      properties:
>> +        clock-names:
>> +          items:
>> +            - const: aclk200
>> +            - const: aclk400_mcuisp
>> +      required:
>> +        - clocks
>> +        - clock-names
>> +        - power-domains
>> +
>>  examples:
>>    - |
>>      #include <dt-bindings/clock/exynos5250.h>
>> -- 
>> 2.30.2
>>
>>


Best regards,
Krzysztof