RE: [PATCH 1/2] arm64: dts: ls1028a: add missing CAN nodes

[Leo Li <leoyang.li@nxp.com>]

> -----Original Message-----
> From: Michael Walle <michael@walle.cc>
> Sent: Thursday, September 24, 2020 6:31 AM
> To: Leo Li <leoyang.li@nxp.com>
> Cc: linux-arm-kernel@lists.infradead.org; devicetree@vger.kernel.org; linux-
> kernel@vger.kernel.org; linux-can@vger.kernel.org; Shawn Guo
> <shawnguo@kernel.org>; Rob Herring <robh+dt@kernel.org>; Marc Kleine-
> Budde <mkl@pengutronix.de>; Joakim Zhang <qiangqing.zhang@nxp.com>
> Subject: Re: [PATCH 1/2] arm64: dts: ls1028a: add missing CAN nodes
> 
> Am 2020-09-24 02:35, schrieb Leo Li:
> >> -----Original Message-----
> >> From: Michael Walle <michael@walle.cc>
> >> Sent: Wednesday, September 23, 2020 4:57 AM
> >> To: linux-arm-kernel@lists.infradead.org; devicetree@vger.kernel.org;
> >> linux-
> >> kernel@vger.kernel.org; linux-can@vger.kernel.org
> >> Cc: Shawn Guo <shawnguo@kernel.org>; Leo Li <leoyang.li@nxp.com>;
> Rob
> >> Herring <robh+dt@kernel.org>; Marc Kleine-Budde
> <mkl@pengutronix.de>;
> >> Joakim Zhang <qiangqing.zhang@nxp.com>; Michael Walle
> >> <michael@walle.cc>
> >> Subject: [PATCH 1/2] arm64: dts: ls1028a: add missing CAN nodes
> >>
> >> The LS1028A has two FlexCAN controller. These are compatible with the
> >> ones
> >> from the LX2160A. Add the nodes.
> >>
> >> The first controller was tested on the Kontron sl28 board.
> >>
> >> Signed-off-by: Michael Walle <michael@walle.cc>
> >> ---
> >>  arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi | 18
> >> ++++++++++++++++++
> >>  1 file changed, 18 insertions(+)
> >>
> >> diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
> >> b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
> >> index 0efeb8fa773e..807ee921ec12 100644
> >> --- a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
> >> +++ b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
> >> @@ -386,6 +386,24 @@
> >>  			status = "disabled";
> >>  		};
> >>
> >> +		can0: can@2180000 {
> >> +			compatible = "fsl,ls1028ar1-flexcan", "fsl,lx2160ar1-
> >> flexcan";
> >
> > The explicit compatible strings cannot be found in the binding, but
> > matched by the "fsl,<processor>-flexcan" pattern in the binding.  Is
> > this considered to be acceptable now?
> 
> What is the consequence if it is not acceptable? replacing the pattern
> with individual compatible strings?

There is a recommendation in the kernel documentation quoted below:

  7) The wildcard "<chip>" may be used in compatible strings, as in
     the following example:

         - compatible: Must contain '"nvidia,<chip>-pcie",
           "nvidia,tegra20-pcie"' where <chip> is tegra30, tegra132, ...

     As in the above example, the known values of "<chip>" should be
     documented if it is used.

But I am not sure if this is still a hard requirement.  If so, we should list the processors in the binding.

Regards,
Leo