Re: [PATCH 2/3] Documentation: bindings: add usb3-host-disable and usb3-host-port for Rockchip USB Type-C PHY

[Brian Norris]

Hi,

On Mon, Feb 12, 2018 at 10:43:41AM -0600, Rob Herring wrote:
> On Thu, Feb 8, 2018 at 3:23 PM, Enric Balletbo Serra
> <eballetbo@xxxxxxxxx> wrote:
> > 2018-02-08 18:52 GMT+01:00 Rob Herring <robh@xxxxxxxxxx>:
> >> On Thu, Feb 8, 2018 at 9:20 AM, Enric Balletbo i Serra
> >> <enric.balletbo@xxxxxxxxxxxxx> wrote:
> >>> --- a/Documentation/devicetree/bindings/phy/phy-rockchip-typec.txt
> >>> +++ b/Documentation/devicetree/bindings/phy/phy-rockchip-typec.txt
> >>> @@ -36,6 +36,12 @@ offset, enable bit, write mask bit.
> >>>   - rockchip,uphy-dp-sel : the register of type-c phy enable DP function
> >>>     for type-c phy0, it must be <0x6268 19 19>;
> >>>     for type-c phy1, it must be <0x6268 3 19>;
> >>> + - rockchip,usb3-host-disable : the register of type-c phy disable usb3 host
> >>> +   for type-c phy0, it must be <0x2434 0 16>;
> >>> +   for type-c phy1, it must be <0x2444 0 16>;
> >>> + - rockchip,usb3-host-port : the register of type-c phy usb3 port number
> >>> +   for type-c phy0, it must be <0x2434 12 28>;
> >>> +   for type-c phy1, it must be <0x2444 12 28>;
> >>
> >> When does this list stop? Adding properties for various register
> >> fields doesn't scale. This information should be in the driver and
> >> based on the compatible string if necessary.
> >>
> >
> > I see, seams reasonable to me, is this applicable to the new ones only
> > or I should get rid of all the proprieties like this from the DT
> > (including the old ones)?
> 
> We're already kind of stuck with the existing ones. So it depends if
> people want to phase them out or not.

FWIW, any Chrome{device} using these sort of bindings is perfectly
capable of handling changed bindings (we ship DTBs with the kernel). But
that's not typically how mainline covers binding deprecation.

If we're going to start recommending not putting these offsets in the
DT, I'd vote for deprecating them, for consistency. (Otherwise, we'll
keep running into this same question.) We only documented the RK3399
("rockchip,rk3399-typec-phy") binding, so all users should have the same
offsets. I dunno if/how we pick a time for eventually removing the
bindings entirely.

Brian