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

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Message-ID: <CANBLGcykb99SntD=C67_-iUoZZLeFfMw8jZWdF9fmFss3u24iA@mail.gmail.com>
Date:   Tue, 13 Feb 2018 10:18:35 +0100
From:   Emil Renner Berthing <emil.renner.berthing@...il.com>
To:     Rob Herring <robh@...nel.org>
Cc:     Brian Norris <briannorris@...omium.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        Heiko Stuebner <heiko@...ech.de>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>,
        Enric Balletbo Serra <eballetbo@...il.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Doug Anderson <dianders@...omium.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        Chris Zhong <zyw@...k-chips.com>,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        William wu <wulf@...k-chips.com>, kernel@...labora.com,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        huang lin <hl@...k-chips.com>
Subject: Re: [PATCH 2/3] Documentation: bindings: add usb3-host-disable and
 usb3-host-port for Rockchip USB Type-C PHY

On 12 February 2018 at 23:29, Rob Herring <robh@...nel.org> wrote:
> On Mon, Feb 12, 2018 at 3:26 PM, Brian Norris <briannorris@...omium.org> wrote:
>> 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@...il.com> wrote:
>>> > 2018-02-08 18:52 GMT+01:00 Rob Herring <robh@...nel.org>:
>>> >> On Thu, Feb 8, 2018 at 9:20 AM, Enric Balletbo i Serra
>>> >> <enric.balletbo@...labora.com> 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 it's CrOS only that's using these, then it's really up to you all.
> I guess it depends if many folks are trying to run mainline on CrOS
> devices and don't necessarily keep things in sync.

For what it's worth I run mainline on my Chromebook Plus (rk3399-gru-kevin),
but in order to have a somewhat working setup you need to run
4.16-rc1 + various patches from the rockchip mailing list which means
you have to keep up with the latest mainline (both kernel and devicetree)
anyway. So I'm all in favour of cleaning up the devicetree.

>> 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.
>
> Yes, makes sense.
>
> Rob
>
> _______________________________________________
> Linux-rockchip mailing list
> Linux-rockchip@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-rockchip

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