Re: [PATCH v4 1/1] USB: core: let USB device know device node

[Philipp Zabel <p.zabel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

Am Freitag, den 05.02.2016, 14:11 +0800 schrieb Peter Chen:
[...]
> > The reference recommendation states that for single-configuration USB
> > devices the compatible should contain all of the applicable strings from
> > the list starting with 2) "usbVID,PID.REV" and ending with 11)
> > "usb,device". Are we going to ignore this?
>
> I have not seen benefits if we write several compatibles in dts,
> the information of compatibles listed in doc can be got during
> the enumeration.
> 
> I suggest we use the simple pattern for this compatible, in that
> case, every one can be easy to follow it, and will not be confused
> which compatibles should be used, and the style can be unify.

Just pointing it out, a comment why this differs from the recommendation
would be nice to avoid confusion.

[...]
> > > +		compatible = "usb05e3,0608";
> > > +		reg = <0x1>;
> > > +	};
> > 
> > I'd have written this node as:
> > 
> > 	hub: hub@1 {
> > 		compatible = "usb5e3,608", "usb5e3,class9",
> > 			     "usb,class9", "usb,device";
> > 		reg = <1>;
> > 	};
> 
> The reg should be hexadecimal, do we need to add "0x" before the value?

The unit-address name part should be hexadecimal, the reg property value
doesn't have to be. As long as the value is < 10 I don't see a problem.

> > As another example, I'd like to introduce the USB WLAN Adapter soldered
> > onto the imx6q-gk802 board to its power enable GPIO via the device tree:
> > 
> > /* Internal USB port (USBH1) */
> > &usbh1 {
> > 	#address-cells = <1>;
> > 	#size-cells = <0>;
> > 	status = "okay";
> > 
> > 	/* RTL8192CU 802.11n WLAN Adapter */
> > 	device@1 {
> > 		compatible = "usbbda,8176.200", "usbbda,8176",
> > 			     "usb,device";
> > 		reg = <1>;
> > 
> > 		enable-gpios = <&gpio2 0 GPIO_ACTIVE_LOW>;
> > 	};
> > };
> > 
> 
> It is okay to use your example, but I still insist like below:

Sorry for being imprecise. The hub example is fine for the
documentation. I just wanted to illustrate how and why I am interested
in this discussion.

best regards
Philipp

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