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@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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