rtc: bindings: Provide ST bindings for ST's LPC RTC device

On current ST platforms the LPC controls a number of functions including
Watchdog and Real Time Clock.  This patch provides the bindings used to
configure LPC in RTC mode.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/Documentation/devicetree/bindings/rtc/rtc-st-lpc.txt b/Documentation/devicetree/bindings/rtc/rtc-st-lpc.txt
new file mode 100644 (file)
index 0000000..73407f5
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/rtc-st-lpc.txt
@@ -0,0 +1,25 @@
+STMicroelectronics Low Power Controller (LPC) - RTC
+===================================================
+
+LPC currently supports Watchdog OR Real Time Clock functionality.
+
+[See: ../watchdog/st_lpc_wdt.txt for Watchdog options]
+
+Required properties
+
+- compatible   : Must be one of: "st,stih407-lpc" "st,stih416-lpc"
+                                 "st,stih415-lpc" "st,stid127-lpc"
+- reg          : LPC registers base address + size
+- interrupts    : LPC interrupt line number and associated flags
+- clocks       : Clock used by LPC device (See: ../clock/clock-bindings.txt)
+- st,lpc-mode  : The LPC can run either one of two modes ST_LPC_MODE_RTC [0] or
+                 ST_LPC_MODE_WDT [1].  One (and only one) mode must be
+                 selected.
+
+Example:
+       lpc@fde05000 {
+               compatible      = "st,stih407-lpc";
+               reg             = <0xfde05000 0x1000>;
+               clocks          = <&clk_s_d3_flexgen CLK_LPC_0>;
+               st,lpc-mode     = <ST_LPC_MODE_RTC>;
+       };