On 11/10/2017 01:35 PM, Pankaj Bansal wrote: >>> 3. Regarding backward compatibility with PowerPC, I see that there is only one platform in PowerPC architecture that is using flexcan. >>> There is only one platform in "arch/powerpc/boot/dts/" having flexcan node. p1010si-post.dtsi >>> I have added the big-endian property in that platform and have tested it on P1010 platform after backporting the patch to Freescale SDK 1.4 linux. >>> I have sent the patch for this. See "[PATCH 2/3] powerpc: dts: P1010: Add endianness property to flexcan node" >>> I believe these changes can be accepted for both powerpc and arm and other architectures that use flexcan. >> >> No, this is not acceptable. You break the device tree. Please add the le, be information to the devtype data. > > I don't understand how this breaks device tree? can you please elaborate? This method is already being used in other specifications. Boot a new kernel with an old tree on a PPC board -> flexcan will not work. See this talk for more information for stable device tree ABI: https://elinux.org/images/0/0e/OSELAS.Presentation-ELCE2017-DT.pdf https://www.youtube.com/watch?v=6iguKSJJfxo > You can refer "Documentation/devicetree/bindings/usb/usb-ehci.txt" or > "Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt" Or > "Documentation/devicetree/bindings/regmap/regmap.txt". > In my opinion, keeping this info in devtype data is not good idea. > E.g. say two platforms which have same FlexCAN hardware revision, > will have same quirks. BUT these two platforms implement FlexCAN in > le and be fashion respectively. Then it's two different platforms. Simply add another compatible to the driver. > With current FlexCAN driver, these two platforms can have same > devtype data. And we need not to change flexcan.c if we want to add > support for a second platform. We can just add device tree for that > platform (which would be needed anyway), and it can work. We can > mention endianness in device tree. Marc -- Pengutronix e.K. | Marc Kleine-Budde | Industrial Linux Solutions | Phone: +49-231-2826-924 | Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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