Messages in this thread | | | Date | Wed, 10 Sep 2014 14:14:24 +0200 | From | Johan Hovold <> | Subject | Re: [PATCH 5/5] rtc: at91sam9: add DT bindings documentation |
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On Wed, Sep 03, 2014 at 10:45:34AM +0200, Boris BREZILLON wrote: > Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com> > --- > .../devicetree/bindings/rtc/atmel,at91sam9-rtc.txt | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > create mode 100644 Documentation/devicetree/bindings/rtc/atmel,at91sam9-rtc.txt > > diff --git a/Documentation/devicetree/bindings/rtc/atmel,at91sam9-rtc.txt b/Documentation/devicetree/bindings/rtc/atmel,at91sam9-rtc.txt > new file mode 100644 > index 0000000..9ca455f > --- /dev/null > +++ b/Documentation/devicetree/bindings/rtc/atmel,at91sam9-rtc.txt > @@ -0,0 +1,20 @@ > +Atmel AT91SAM9260 Real Time Timer > + > +Required properties: > +- compatible: should be: "atmel,at91sam9260-rtt" > +- reg: should contain 2 memory regions > + * the first one encodes the memory region of the RTT controller > + * the second one encodes the GPBR (General Purpose Backup Resgisters) > + memory region used to store the current time > +- interrupts: rtc alarm/event interrupt > +- clocks: should contain one clock pointing the the slow clk > + > +Example: > + > +rtc@fffffe00 { > + compatible = "atmel,at91sam9260-rtt"; > + reg = <0xfffffd20 0x10 > + 0xfffffd50 0x4>; > + interrupts = <1 4 7>; > + clocks = <&clk32k>; > +};
This does not describe the hardware, but rather a specific software configuration.
The RTT is first of all not an RTC (although it can be used as one in a specific software configuration). And the second register resource above is not an RTT register, but a general-purpose backup register could be used for other purposes (which register to use is currently configurable for legacy booting using CONFIG_RTC_DRV_AT91SAM9_GPBR).
This was discussed in the thread where I posted an RFC for this last year (which you linked to in your original submission thread), but no conclusion was reached:
http://www.spinics.net/lists/arm-kernel/msg236292.html
Johan
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