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

[Philipp Zabel]

Am Donnerstag, den 24.11.2016, 18:20 +0800 schrieb 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.

I don't understand this, does the clock driver bind to the iomcu node
using CLK_OF_DECLARE_DRIVER(..., "hisilicon,hi3660-iomcu", ...)?

My comment was based only on this reset binding documentation and the
example DT snippet. Could you point me to the clock driver probe code
and show me a more complete part of the hi3660 device tree?

regards
Philipp