On 05/30/2017 08:23 PM, Andy Shevchenko wrote: > On Sun, May 28, 2017 at 9:39 PM, Hauke Mehrtens <hauke@xxxxxxxxxx> wrote: >> From: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx> >> >> Instead of hacking the configuration of the FPI bus into the arch code >> add an own bus driver for this internal bus. The FPI bus is the main >> bus of the SoC. This bus driver makes sure the bus is configured >> correctly before the child drivers are getting initialized. This driver >> will probably also be used on different SoC later. > >> +Optional properties: >> +- regmap : A phandle to the RCU syscon > >> +- offset-endianness : Offset of the endianness configuration register > > Shouldn't be one of > > big-endian; > little-endian; > native-endian; > > ? The offset-endianness is the offset of the endianes register in the RCU register range which is accessed through the syscon. For the SoCs where I checked it is the same value. I should add a documentation of big-endian. > For what purpose that register is used? > Is it configurable in RTL? IOW why you need to have it in DT? > >> + offset-endianness = <0x4c>; >> + big-endian; > >> + /* RCU configuration is optional */ >> + rcu_regmap = syscon_regmap_lookup_by_phandle(np, "regmap"); > >> + if (!IS_ERR_OR_NULL(rcu_regmap)) { > > _OR_NULL is suspicious. You are doing something wrong. > This is only needed for some SoCs, some chips do not have this register. Should I do this based on the compatibility string? Hauke -- 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