[PATCHv1] rtc: bcm-iproc: Add support for Broadcom iproc rtc

Arnd Bergmann arnd at arndb.de
Wed Mar 11 13:31:42 PDT 2015

On Wednesday 11 March 2015 13:00:22 Arun Ramamurthy wrote:
> Arnd, this is the device tree entry that I would end up with and I plan 
> to use syscon_regmap_lookup_by_phandle in the rtc driver. Does this look 
> acceptable?
> rtc: iproc_rtc at 0x03026000 {
>                 compatible = "brcm,iproc-rtc";
>                 reg =   <0x03026000 0xC>,
>                 iso_cell_syscon = <&crmu_iso_cell_control>;
>                 bbl_auth_syscon = <&crmu_bbl_auth>
>                 status = "okay";
> crmu_iso_cell_control:crmu at 0x0301C02C {
>                 compatible = "syscon";
>                 reg = <0x0301C038 0x8>
> }
> crmu_bbl_auth:crmu at 0x03024C74 {
>                 compatible = "syscon";
>                 reg = <0x03024C74 0x8>;
> }

This doesn't look right, sorry:

A syscon device is defined as a collection of registers that
have no logical grouping within them but that can be seen
as a single device. What you have here instead are two syscon
nodes that each have only a single 8-byte register.

What are the other registers surrounding those? I would expect
something like

	crmu0: syscon at 03010000 {
                 compatible = "syscon";
                 reg = <0x03010000 0x10000>;

and then use an offset into the syscon from the rtc node, like

	iproc_rtc: rtc at 03026000 {
		compatible = "brcm,iproc-rtc";
		reg = <0x03026000 0x1000>;
		iso_cell_syscon = <&crmu0 0xc038>;
		bbl_auth_syscon = <&crmu1 0x4c74>;

Note also that you got most of the naming wrong:

- node names should be generic strings like "rtc", "syscon", "pci" etc.
  The specific strings are defined in ePAPR.
- unit addresses should match the first 'reg' property and
  not start with '0x'.
- it seems strange that the rtc has only 12 bytes of registers,
  though that may actually be correct.


More information about the linux-arm-kernel mailing list