Re: [PATCH 3/4] dt-bindings: mt8173-mtu3: add generic compatible and rename file

[Chunfeng Yun]

On Mon, 2017-08-14 at 13:23 +0200, Matthias Brugger wrote:
> 
> On 08/11/2017 09:00 AM, Chunfeng Yun wrote:
> > On Thu, 2017-08-10 at 21:54 -0500, Rob Herring wrote:
> >> On Tue, Aug 08, 2017 at 01:42:51PM +0800, Chunfeng Yun wrote:
> >>> The mt8173-mtu3.txt actually holds the bindings for all mediatek
> >>> SoCs with usb3 DRD IP, so add a generic compatible and change the
> >>> name to mtu3.txt.
> >>>
> >>> Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
> >>> ---
> >>>   .../bindings/usb/{mt8173-mtu3.txt => mtu3.txt}     |    6 ++++--
> >>>   1 file changed, 4 insertions(+), 2 deletions(-)
> >>>   rename Documentation/devicetree/bindings/usb/{mt8173-mtu3.txt => mtu3.txt} (95%)
> >>>
> >>> diff --git a/Documentation/devicetree/bindings/usb/mt8173-mtu3.txt b/Documentation/devicetree/bindings/usb/mtu3.txt
> >>> similarity index 95%
> >>> rename from Documentation/devicetree/bindings/usb/mt8173-mtu3.txt
> >>> rename to Documentation/devicetree/bindings/usb/mtu3.txt
> >>> index 1d7c3bc..832741d 100644
> >>> --- a/Documentation/devicetree/bindings/usb/mt8173-mtu3.txt
> >>> +++ b/Documentation/devicetree/bindings/usb/mtu3.txt
> >>
> >> mediatek,mtu3.txt
> > Ok
> >>
> >>> @@ -1,7 +1,9 @@
> >>>   The device node for Mediatek USB3.0 DRD controller
> >>>   
> >>>   Required properties:
> >>> - - compatible : should be "mediatek,mt8173-mtu3"
> >>> + - compatible : should be one of
> >>> +	"mediatek,mt8173-mtu3" (deprecated, use "mediatek,mtu3" instead),
> >>
> >> NAK. You can add generic compatibles, but you need SoC specific ones in
> >> addition.
> > It's for backward compatibility
> > 
> 
> I think backwards compatibility should be in the driver but not in the binding 
> description. Apart from that device tree files will need to provide a SoC 
> specific binding apart from the generic one, for example:
> 
> "mediatek,mt8173-mtu3", "mediatek,mtu3": for mt8173
> "mediatek,mt7623-mtu3", "mediatek,mtu3": for mt6723
> 
> This is needed to cover possible bugs/features that can be found in the future 
> for a specific SoC. The driver can match just against the generic binding and 
> will only implement a match against the SoC specific one if a bug/feature is 
> present.
> 
> Makes sense?
Got it, thanks a lot
> 
> Regards,
> Matthias