Subject: [PATCH 3/3] ARM: bcm2835: Add the necessary firmware driver information to the DT

From: [email-masked] (Stephen Warren)
Date: Wed, 29 Apr 2015 17:43:32 -0600

On 04/29/15 10:29, Eric Anholt wrote:
> Stephen Warren <[email-masked]> writes:
>
>> On 04/27/2015 05:14 PM, Eric Anholt wrote:
>>> This gets the USB power domain turned on so that DWC2 can probe, even
>>> if the bootloader didn't turn it on for us (which is the case if you
>>> use the RPi firmware without chainloading U-Boot).
>>
>>> diff --git a/arch/arm/boot/dts/bcm2835-rpi.dtsi b/arch/arm/boot/dts/bcm2835-rpi.dtsi
>>
>>> +&usb {
>>> +	power-domains = <&firmware POWER_DOMAIN_USB>;
>>> +};
>>
>> That property doesn't seem to be documented in
>> Documentation/devicetree/bindings/usb/dwc2.txt (which defines compatible
>> = "brcm,bcm2835-usb"). Is it implemented?
>
> power-domains is a generic property that's parsed by
> drivers/base/power/domain.c.  See also
> Documentation/devicetree/bindings/power/power_domain.txt&

Sure, but the binding for the node still needs to mention that it's 
acceptable for that property to exist (a/k/a that the USB binding 
inherits from or aggregates the power domains binding). Part of 
mentioning that would be a description of what the entries in the 
power-domains property mean (how many are legal, what each index 
represents).