drivers/rtc/rtc-sirfsoc.c: add rtc drivers for CSR SiRFprimaII and SiRFatlasVI

On CSR SiRFprimaII/atlasVI, there is a programmable 16-bit divider
(RTC_DIV) that divides the input 32.768KHz clock to the frequency that
users need (E.g.  1 Hz).  The divided real-time clock will be used to
drive a 32-bit counter (RTC_COUNTER) that provides users with the actual
time.

In each cycle of the divided real-time clock, there is a Hertz interrupt
generated to the RISC.  Users can also configure an alarm (RTC_ALARM).
When RTC_COUNTER matches the alarm, there will be an alarm interrupt
generated to the RISC.

The system RTC can generate an alarm wake-up signal to notify the power
controller to wake up from power saving mode.

Signed-off-by: Xianglong Du <Xianglong.Du@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Cc: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/arm/boot/dts/atlas6.dtsi b/arch/arm/boot/dts/atlas6.dtsi
index 7d1a279..9866cd7 100644
--- a/arch/arm/boot/dts/atlas6.dtsi
+++ b/arch/arm/boot/dts/atlas6.dtsi
@@ -613,7 +613,7 @@
 		};
 
 		rtc-iobg {
-			compatible = "sirf,prima2-rtciobg", "sirf-prima2-rtciobg-bus";
+			compatible = "sirf,prima2-rtciobg", "sirf-prima2-rtciobg-bus", "simple-bus";
 			#address-cells = <1>;
 			#size-cells = <1>;
 			reg = <0x80030000 0x10000>;
diff --git a/arch/arm/boot/dts/prima2.dtsi b/arch/arm/boot/dts/prima2.dtsi
index 02edd89..05e9489 100644
--- a/arch/arm/boot/dts/prima2.dtsi
+++ b/arch/arm/boot/dts/prima2.dtsi
@@ -610,7 +610,7 @@
 		};
 
 		rtc-iobg {
-			compatible = "sirf,prima2-rtciobg", "sirf-prima2-rtciobg-bus";
+			compatible = "sirf,prima2-rtciobg", "sirf-prima2-rtciobg-bus", "simple-bus";
 			#address-cells = <1>;
 			#size-cells = <1>;
 			reg = <0x80030000 0x10000>;