On Wednesday 15 January 2014, Marc Carino wrote: > + gen-ctrl { > + compatible = "brcm,brcmstb-gen-ctrl-v1"; > + reg = <0xf0404304 0x4 > + 0xf0404308 0x4 > + 0xf03e2578 0x4 > + 0xf03e2488 0x10 > + 0xf0452000 0x20>; > + }; Sorry I didn't get back to you on this when we discussed the previous version. I'm actually less happy with this DT representation than the original. What I take from your description is that you have multiple register ranges that basically combine more-or-less random registers that belong into different Linux subsystems. I think the best way to deal with this is to have the "syscon" driver handle the multiplexing between the various drivers that need access to the registers. It would look something like (taking the numbers from your previous patch): ahb { ranges = <0 0xf0000000 0x1000000>; /* 16 MB remapped registers */ hif-cpubuictrl: syscon@3e2400 { compatible = "brcm,7445-cpubioctrl", "syscon"; reg = <0x3e2000, 0x1000>; }; hif-continuation: syscon@45200 { compatible = "brcm,7445-hif-continuation", "syscon"; reg = <0x452000, 0x1000>; }; sun-top-ctrl: ... }; This lets the syscon driver find and map the three register areas. Drivers that need access to the registers then do reset { compatible = "brcm,7445-reset-ctrl"; syscon = <&sun-top-ctrl 0x300 0x100>; #reset-cells = <1>; }; And then you can add a regular device driver to drivers/reset that provides a device_reset() API to other drivers, or a system-reset function to be registered as arm_pm_restart. This driver would use syscon_regmap_lookup_by_phandle() to get access to a regmap pointer, and then use either hardcoded offsets into the regmap, or get those offsets from numbers in the devicetree, as provided in the example above. Arnd -- 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