[U-Boot] rk3xxx.dtsi /usb_host missing specific compatible

[Heiko Stuebner <heiko@sntech.de>]

Am Freitag, 25. August 2017, 13:20:47 CEST schrieb Philipp Tomsich:
> + Heiko
> 
> On Wed, 23 Aug 2017, Artturi Alm wrote:
> 
> > Hi,
> >
> >
> > no idea if this is the right place to mail about this, but i got
> > suggested this node is out-of-norm, and the diff below fixes that
> > for me on rk3188.
> >
> > -Artturi
> 
> When submitting changes, please send a patch w/ an appropriate commit 
> message (e.g. using patman).  If you tag it as "rockchip:", it will 
> eventually get assigned to my queue.
> 
> >
> > diff --git a/arch/arm/dts/rk3xxx.dtsi b/arch/arm/dts/rk3xxx.dtsi
> > index 6d9e36d235..21f2afc104 100644
> > --- a/arch/arm/dts/rk3xxx.dtsi
> > +++ b/arch/arm/dts/rk3xxx.dtsi
> > @@ -157,7 +157,7 @@
> > 	};
> >
> > 	usb_host: usb at 101c0000 {
> > -		compatible = "snps,dwc2";
> > +		compatible = "rockchip,rk3066-usb", "snps,dwc2";
> 
> This is the same on the Linux upstream, which is the leading repository
> for this DTS file.  Also, the "rockchip,rk3066-usb" is used by none of the 
> drivers (whereas "snsp,dwc2" is matche by drivers/usb/host/dwc2.c.
> 
> From my point of view, there's no point in changing this (unless Heiko 
> would like to see this changed both here and in Linux).

In general it is common practice to have a more specialized compatible
as a reserve, to be able add "quirks" later on if necessary without needing
devicetree updates as well. For example the otg node does already have
the rk3066-usb compatible.

On the kernel-side, we even do have specialized init values for Rockchip
dwc2 controllers, which is bound to the rk3066-usb compatible. I'm not
sure why only the otg controller got it though and the addition of the
dwc2 nodes in the mainline kernel was already in 2014 :-) .

So I don't have a set opinion one way or another, as it looks like things
work reasonably well as they are now, but if someone sends in a
_tested_ kernel patch setting the specific compatible, I'll look at it
and possibly apply it :-) . 


Heiko