Hi Rob, On mer., mai 31 2017, Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx> wrote: > Hi Rob, > > On mer., mai 31 2017, Rob Herring <robh@xxxxxxxxxx> wrote: >>> >>> Required properties: >>> >>> -- compatible : Should be "marvell,orion-gpio", "marvell,mv78200-gpio" >>> - or "marvell,armadaxp-gpio". "marvell,orion-gpio" should be used for >>> - Orion, Kirkwood, Dove, Discovery (except MV78200) and Armada >>> - 370. "marvell,mv78200-gpio" should be used for the Discovery >>> - MV78200. "marvel,armadaxp-gpio" should be used for all Armada XP >>> - SoCs (MV78230, MV78260, MV78460). >>> +- compatible : Should be "marvell,orion-gpio", "marvell,mv78200-gpio", >>> + "marvell,armadaxp-gpio" or "marvell,armada-8k-gpio". >>> + >>> + "marvell,orion-gpio" should be used for Orion, Kirkwood, Dove, >>> + Discovery (except MV78200) and Armada 370. "marvell,mv78200-gpio" >>> + should be used for the Discovery MV78200. >>> + >>> + "marvel,armadaxp-gpio" should be used for all Armada XP SoCs >>> + (MV78230, MV78260, MV78460). >>> + >>> + "marvell,armada-8k-gpio" should be used for the Armada 7K and 8K >>> + SoCs (either from AP or CP), see >>> + Documentation/devicetree/bindings/arm/marvell/cp110-system-controller0.txt >>> + and >>> + Documentation/devicetree/bindings/arm/marvell/ap806-system-controller.txt >>> + for specific details about the offset property. >>> >>> - reg: Address and length of the register set for the device. Only one >>> entry is expected, except for the "marvell,armadaxp-gpio" variant >>> for which two entries are expected: one for the general registers, >>> - one for the per-cpu registers. >>> + one for the per-cpu registers. Not used for marvell,armada-8k-gpio. >> >> Why can't use you use reg instead of offset? > > I looked for how the other syscon user did, and I found the offset > usage. So I assumed it was the way to do it. But if you wan I can use a > reg property. I had a closer looked to the binding when syscon is used with several subnodes. And actually the reg usage is very uncommon, I only find it in drivers/regulator/pbias-regulator.c but for legacy. I am not sure that we have any benefit with this reg property: we won't use the length of the register and we need to add a range property in the parent node. An other way to pass this information is to have a different compatible string which will match the different offset available. In this case the reg property won't be used in a syscon node. However, while it makes sens for the difference between AP806 and CP110, it would be strange to have a different compatible string for gpio bank 1 and gpio bank 2. So, in the end I would prefer to use the offset. From my point of view it is better to not use the reg property for two different purposes: mmio address vs offset in a syscon. But if you think that from the point of view of the device tree compliance we have to use the reg property, of course I will change it. Thanks, Gregory > > Gregory > >> >> Rob > > -- > Gregory Clement, Free Electrons > Kernel, drivers, real-time and embedded Linux > development, consulting, training and support. > http://free-electrons.com > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
