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

Arnd Bergmann
2015-12-31T14:41:35Z

On Thursday 31 December 2015 22:12:19 Rongrong Zou wrote:
> 在 2015/12/30 17:06, Arnd Bergmann 写道:
> > On Tuesday 29 December 2015 21:33:52 Rongrong Zou wrote:
> >> +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>;
> };

The DT sample above looks good in principle. I believe what you are missing
here is code in your driver to scan the child nodes to create the platform
devices. of_bus_isa_translate() should work with your definition here
and create the correct IORESOURCE_IO resources. You don't have any MMIO
resources, so the absence of a ranges property is ok. Maybe all you
are missing is a call to of_platform_populate() or of_platform_bus_probe()?

Arnd