Re: [PATCH v1 3/3] ARM64 LPC: update binding doc

[Rongrong Zou]

Sorry for so late reply, it is difficult for me to understand ISA config :( .

å 2015/12/30 17:06, Arnd Bergmann åé:
> On Tuesday 29 December 2015 21:33:52 Rongrong Zou wrote:
> > Signed-off-by: Rongrong Zou <zourongrong@xxxxxxxxx>
> > ---
> >   .../devicetree/bindings/arm64/low-pin-count.txt      | 20 ++++++++++++++++++++
> >   1 file changed, 20 insertions(+)
> >   create mode 100644 Documentation/devicetree/bindings/arm64/low-pin-count.txt
> >
> > diff --git a/Documentation/devicetree/bindings/arm64/low-pin-count.txt b/Documentation/devicetree/bindings/arm64/low-pin-count.txt
> > new file mode 100644
> > index 0000000..215f2c4
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/arm64/low-pin-count.txt
> > @@ -0,0 +1,20 @@
> > +Low Pin Count bus driver
> > +
> > +Usually LPC controller is part of PCI host bridge, so the legacy ISA
> > +port locate on LPC bus can be accessed directly. But some SoC have
> > +independent LPC controller, and we can access the legacy port by specifying
> > +LPC address cycle. Thus, LPC driver is introduced.
> > +
> > +Required properties:
> > +- compatible: "low-pin-count"
> > +- reg: specifies low pin count address range
> > +
> > +
> > +Example:
> > +
> > +        lpc_0: lpc@a01b0000 {
> > +		#address-cells = <1>;
> > +		#size-cells = <1>;
> > +                compatible = "low-pin-count";
> > +                reg = <0x0 0xa01b0000 0x0 0x10000>;
> > +        };
>
> One more thought: please try to stick as closely as possible to the existing
> ISA binding that is documented at
>
> http://www.firmware.org/1275/bindings/isa/isa0_4d.ps
From the specification, I think I should use 2 32bit integer to describe the isa addr in dts.
> In particular, this should cover the possibility of describing both memory
> and I/O spaces in child devices.

I found below config in powerpc dts "arch/powerpc/boot/dts/mpc8544ds.dts"

isa@1e {
                                device_type = "isa";
                                #interrupt-cells = <2>;
                                #size-cells = <1>;
                                #address-cells = <2>;
                                reg = <0xf000 0x0 0x0 0x0 0x0>;
                                ranges = <0x1 0x0 0x1000000 0x0 0x0
                                          0x1000>;
                                interrupt-parent = <&i8259>;



                                rtc@70 {
                                        compatible = "pnpPNP,b00";
                                        reg = <0x1 0x70 0x2>;
                                };
 the isa space in child-node: reg = <0x1 0x70 0x2>;
 0x1 means IO space, 70 means addr, 0x2 is size.
 but when i config the following in dts, the ipmi_0 node can't be probed,
 I think there may be some problems.

lpc_0: lpc@a01b0000 {
	compatible = "low-pin-count";
	device_type = "isa";
	#address-cells = <2>;
	#size-cells = <1>;
	reg = <0x0 0xa01b0000 0x0 0x10000>;

	ipmi_0:ipmi@000000e4{
		device_type = "ipmi";
		compatible = "ipmi-bt";
		reg = <0x1 0x000000e4 0x4>;
};







> 	Arnd
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