[RFC v2: PATCH 1/2] dt-bindings: Document the hi3660 reset bindings

[zhangfei]

On 2016年11月24日 17:50, Philipp Zabel wrote:
> Am Donnerstag, den 24.11.2016, 17:40 +0800 schrieb zhangfei:
>> On 2016年11月24日 17:26, Philipp Zabel wrote:
>>> Am Mittwoch, den 23.11.2016, 16:07 +0800 schrieb Zhangfei Gao:
>>>> Add DT bindings documentation for hi3660 SoC reset controller.
>>>>
>>>> Signed-off-by: Zhangfei Gao <zhangfei.gao at linaro.org>
>>>> ---
>>>>    .../bindings/reset/hisilicon,hi3660-reset.txt      | 51 ++++++++++++++++++++++
>>>>    1 file changed, 51 insertions(+)
>>>>    create mode 100644 Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt b/Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt
>>>> new file mode 100644
>>>> index 0000000..250daf2
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt
>>>> @@ -0,0 +1,51 @@
>>>> +Hisilicon System Reset Controller
>>>> +======================================
>>>> +
>>>> +Please also refer to reset.txt in this directory for common reset
>>>> +controller binding usage.
>>>> +
>>>> +The reset controller registers are part of the system-ctl block on
>>>> +hi3660 SoC.
>>>> +
>>>> +Required properties:
>>>> +- compatible: should be
>>>> +		 "hisilicon,hi3660-reset"
>>>> +- #reset-cells: 1, see below
>>>> +- hisi,rst-syscon: phandle of the reset's syscon.
>>>> +- hisi,reset-bits: Contains the reset control register information
>>>> +		  Should contain 2 cells for each reset exposed to
>>>> +		  consumers, defined as:
>>>> +			Cell #1 : offset from the syscon register base
>>>> +			Cell #2 : bits position of the control register
>>>> +
>>>> +Example:
>>>> +	iomcu: iomcu at ffd7e000 {
>>>> +		compatible = "hisilicon,hi3660-iomcu", "syscon";
>>>> +		reg = <0x0 0xffd7e000 0x0 0x1000>;
>>>> +	};
>>>> +
>>>> +	iomcu_rst: iomcu_rst_controller {
>>> This should be
>>> 	iomcu_rst: reset-controller {
>>>
>>>> +		compatible = "hisilicon,hi3660-reset";
>>>> +		#reset-cells = <1>;
>>>> +		hisi,rst-syscon = <&iomcu>;
>>>> +		hisi,reset-bits = <0x20 0x8		/* 0: i2c0 */
>>>> +				   0x20 0x10		/* 1: i2c1 */
>>>> +				   0x20 0x20		/* 2: i2c2 */
>>>> +				   0x20 0x8000000>;	/* 3: i2c6 */
>>>> +	};
>>> The reset lines are controlled through iomcu bits, is there a reason not
>>> to put the iomcu_rst node inside the iomcu node? That way the
>>> hisi,rst-syscon property could be removed and the syscon could be
>>> retrieved via the reset-controller parent node.
>> iomcu is common registers, controls clock and reset, etc.
>> So we use syscon, without mapping the registers everywhere.
>> It is common case in hisilicon, same in hi6220.
>>
>> Also the #clock-cells and #reset-cells can not be put in the same node,
>> if they are both using probe, since reset_probe will not be called.
>>
>> So we use hisi,rst-syscon as a general solution.
> What I meant is this:
>
> 	iomcu: iomcu at ffd7e000 {
> 		compatible = "hisilicon,hi3660-iomcu", "syscon", "simple-mfd";
> 		reg = <0x0 0xffd7e000 0x0 0x1000>;
#clock-cells = <1>;
In my test, if there add #clock-cells = <1>, reset_probe will not be 
called any more.
Since clk_probe is called first.
No matter iomcu_rst is child node or not.

Thanks
>
> 		iomcu_rst: reset-controller {
> 			compatible = "hisilicon,hi3660-reset";
> 			#reset-cells = <1>;
> 			hisi,reset-bits = <0x20 0x8		/* 0: i2c0 */
> 					   0x20 0x10		/* 1: i2c1 */
> 					   0x20 0x20		/* 2: i2c2 */
> 					   0x20 0x8000000>;	/* 3: i2c6 */
> 		};
> 	};
>
> regards
> Philipp
>