On Wed, Jun 02, 2021 at 01:33:07PM +0200, Matthias Brugger wrote: > > > On 01/06/2021 08:07, Chen-Yu Tsai wrote: > > Hi, > > > > On Tue, Jun 1, 2021 at 1:50 PM Jianjun Wang <jianjun.wang@xxxxxxxxxxxx> wrote: > >> > >> On Tue, 2021-06-01 at 11:53 +0800, Chen-Yu Tsai wrote: > >>> Hi, > >>> > >>> On Tue, Jun 1, 2021 at 10:50 AM Jianjun Wang <jianjun.wang@xxxxxxxxxxxx> wrote: > >>>> > >>>> MT8195 is an ARM platform SoC which has the same PCIe IP with MT8192. > >>> > >>> Based on what I'm seeing internally, there seems to be some inconsistency > >>> across the MediaTek platform on whether new compatible strings should be > >>> introduced for "fully compatible" IP blocks. > >>> > >>> If this hardware block in MT8195 is "the same" as the one in MT8192, do we > >>> really need the new compatible string? Are there any concerns? > >> > >> Hi Chen-Yu, > >> > >> It's ok to reuse the compatible string with MT8192, but I think this > >> will be easier to find which platforms this driver is compatible with, > >> especially when we have more and more platforms in the future. > > > > If it's just for informational purposes, then having the MT8192 compatible > > as a fallback would work, and we wouldn't need to make changes to the driver. > > This works better especially if we have to support multiple operating systems > > that use device tree. > > > > So we would want > > > > "mediatek,mt8195-pcie", "mediatek,mt8192-pcie" > > > > and > > > > "mediatek,mt8192-pcie" > > > > be the valid options. > > > > Personally I'm not seeing enough value to justify adding the compatible string > > just for informational purposes though. One could easily discern which hardware > > is used by looking at the device tree. > > > > I agree, if no differences between the two chips are known, adding a > binding withe new compatible and a fallback is a good thing. If we > later on realize that mt8195 PCI block has differences, we can add the > matching to the driver. So this series can be dropped, right ? Thanks, Lorenzo > Regards, > Matthias > > > > > Regards > > ChenYu > > > > > >> Thanks. > >>> > >>> > >>> Thanks > >>> ChenYu > >>> > >>> > >>>> Signed-off-by: Jianjun Wang <jianjun.wang@xxxxxxxxxxxx> > >>>> --- > >>>> Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml | 4 +++- > >>>> 1 file changed, 3 insertions(+), 1 deletion(-) > >>>> > >>>> diff --git a/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml b/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml > >>>> index e7b1f9892da4..d5e4a3e63d97 100644 > >>>> --- a/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml > >>>> +++ b/Documentation/devicetree/bindings/pci/mediatek-pcie-gen3.yaml > >>>> @@ -48,7 +48,9 @@ allOf: > >>>> > >>>> properties: > >>>> compatible: > >>>> - const: mediatek,mt8192-pcie > >>>> + oneOf: > >>>> + - const: mediatek,mt8192-pcie > >>>> + - const: mediatek,mt8195-pcie > >>>> > >>>> reg: > >>>> maxItems: 1 > >>>> -- > >>>> 2.18.0 > >>>> _______________________________________________ > >>>> Linux-mediatek mailing list > >>>> Linux-mediatek@xxxxxxxxxxxxxxxxxxx > >>>> http://lists.infradead.org/mailman/listinfo/linux-mediatek > >>
