[PATCH v3] ARM: dts: witherspoon: add Epson RX8900CE RTC module

[Chris Smart <chris@distroguy.com>]

This commit adds the relevant device tree entry for the Epson RX8900CE
RTC module on the I2C bus.

Note that there are two options that we may need to set.

If there is no connected battery:
 epson,vdet-disable;

If there is no trickle charge diode:
 epson,vdet-disable;

These are currently left commented out in the commit.

Signed-off-by: Chris Smart <chris@distroguy.com>
---

Changes since v1:
	- fixed up the entry for rtc@32

Changes since v2:
	- fix up code formatting

Tested with kernel config from openbmc meta-ast2500 yocto, compiled
with:

ARCH=arm CROSS_COMPILE=arm-linux-gnu- make -j$(nproc) dtbs


 arch/arm/boot/dts/aspeed-bmc-opp-witherspoon.dts | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm/boot/dts/aspeed-bmc-opp-witherspoon.dts b/arch/arm/boot/dts/aspeed-bmc-opp-witherspoon.dts
index 328a9c4e189e..2972c6279183 100644
--- a/arch/arm/boot/dts/aspeed-bmc-opp-witherspoon.dts
+++ b/arch/arm/boot/dts/aspeed-bmc-opp-witherspoon.dts
@@ -148,7 +148,19 @@
 
 	/* TPM */
 	/* 9552 */
+
 	/* RTC */
+	rtc@32 {
+		compatible = "epson,rx8900";
+		reg = <0x32>;
+		/*
+		 * If no battery, set this:
+		 * epson,vdet-disable;
+		 * If no trickle charge diode, set this:
+		 * epson,vdet-disable;
+		 */
+	};
+
 	/* EEPROM */
 
 	eeprom@51 {
-- 
2.9.3