Rob Herring <robh+dt@xxxxxxxxxx> writes:
> Like PCI, USB, SDIO, etc., you need to define an AC97 bus binding
> which defines child node structure, compatible formatting (if you can
> base compatibles on something like VID/PID), and addressing (reg and
> unit-address formats). Then once you define child nodes, you can add
> whatever sideband connections you need. The AC97 core should be able
> to populate struct device_node if there are any matching child
> devices.
Ok, I thing I understand.
So the device-tree will look like :
ac97: sound@40500000 {
compatible = "marvell,pxa270-ac97";
reg = < 0x40500000 0x1000 >;
interrupts = <14>;
reset-gpios = <&gpio 95 GPIO_ACTIVE_HIGH>;
#sound-dai-cells = <1>;
pinctrl-names = "default";
pinctrl-0 = < &pinctrl_ac97_default >;
clocks = <&clks CLK_AC97>, <&clks CLK_AC97CONF>;
clock-names = "AC97CLK", "AC97CONFCLK";
wm9713@0 {
reg = <0>; /* Codex index (between 0 and 3) */
compatible = "ac97-codec";
clocks = <&fixed_wm9713_clock>;
clock-names = "ac97_clk";
}
};
And the function ac97_codec_add() will :
- scan the device-tree ac97 controller childs
- match one if its reg equals (in our case wm9713@0)
- set codec->dev.of_node to the matched one
> It gets a bit more complicated if you need to do things like
> enable power or de-assert resets to discover the devices. Sounds like
> that might be the next person's problem in this case. :)
Yeah ... Crossing fingers that won't be me :)
Cheers.
--
Robert
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