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

Rongrong Zou
2015-12-31T14:13:27Z

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

在 2015/12/30 17:06, Arnd Bergmann 写道:
> On Tuesday 29 December 2015 21:33:52 Rongrong Zou wrote:
>> Signed-off-by: Rongrong Zou <zourongrong@gmail.com>
>> ---
>> .../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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