On Sat, Nov 10, 2018 at 12:02 AM Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> wrote: > > Hi Kunihiko, > > On Fri, 2018-11-09 at 10:42 +0900, Kunihiko Hayashi wrote: > > Add compatible strings for reset control of AHCI core implemented in > > UniPhier SoCs. The reset control belongs to AHCI glue layer. > > > > Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx> > > --- > > Documentation/devicetree/bindings/reset/uniphier-reset.txt | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/reset/uniphier-reset.txt b/Documentation/devicetree/bindings/reset/uniphier-reset.txt > > index f63c511..ea00517 100644 > > --- a/Documentation/devicetree/bindings/reset/uniphier-reset.txt > > +++ b/Documentation/devicetree/bindings/reset/uniphier-reset.txt > > @@ -133,6 +133,9 @@ Required properties: > > "socionext,uniphier-pxs2-usb3-reset" - for PXs2 SoC USB3 > > "socionext,uniphier-ld20-usb3-reset" - for LD20 SoC USB3 > > "socionext,uniphier-pxs3-usb3-reset" - for PXs3 SoC USB3 > > + "socionext,uniphier-pro4-ahci-reset" - for Pro4 SoC AHCI > > + "socionext,uniphier-pxs2-ahci-reset" - for PXs2 SoC AHCI > > + "socionext,uniphier-pxs3-ahci-reset" - for PXs3 SoC AHCI > > Since the driver behaves identically for "socionext,uniphier-pro4-usb3- > reset" and "socionext,uniphier-pro4-ahci-reset", would it make sense to > add a common compatible? As far as I could guess, he just happened to find the same driver code could be reused for other hardware. Theoretically, this can happen anywhere since a reset controller is just a set of registers each bit of which is connected to a reset line. If you added a super-generic compatible like "simple-reset", I would agree with "socionext,uniphier-pro4-usb3-reset", "simple-reset" since this is a pattern. However, "socionext,uniphier-pro4-glue-reset" is kind of a halfway house where it is SoC-specific, but still ambiguous. > Something like: > "socionext,uniphier-pro4-usb3-reset", "socionext,uniphier-pro4-glue-reset" - for USB3 SoC AHCI > "socionext,uniphier-pro4-ahci-reset", "socionext,uniphier-pro4-glue-reset" - for Pro4 SoC AHCI > > That way if more places turn up where the glue layer reset is used, > you can add them without patching the driver every time. This is a trade-off between "patch the driver" and "potential change of the binding". There is no real hardware like pro4-glue-reset. I am guessing this is a part of syscon or something, but I cannot find any explanation in a bigger picture. So, I cannot judge this further more. > regards > Philipp -- Best Regards Masahiro Yamada
