[PATCH v8 1/5] Documentation: add sbsa-gwdt driver documentation

[fu.wei@linaro.org]

From: Fu Wei <fu.wei@linaro.org>

The sbsa-gwdt.txt documentation in devicetree/bindings/watchdog is for
introducing SBSA(Server Base System Architecture) Generic Watchdog
device node info into FDT.

Also add sbsa-gwdt introduction in watchdog-parameters.txt

Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Fu Wei <fu.wei@linaro.org>
---
 .../devicetree/bindings/watchdog/sbsa-gwdt.txt     | 46 ++++++++++++++++++++++
 Documentation/watchdog/watchdog-parameters.txt     |  6 +++
 2 files changed, 52 insertions(+)

diff --git a/Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt b/Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt
new file mode 100644
index 0000000..ad8e99a
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt
@@ -0,0 +1,46 @@
+* SBSA (Server Base System Architecture) Generic Watchdog
+
+The SBSA Generic Watchdog Timer is used to force a reset of the system
+after two stages of timeout have elapsed.  A detailed definition of the
+watchdog timer can be found in the ARM document: ARM-DEN-0029 - Server
+Base System Architecture (SBSA)
+
+Required properties:
+- compatible: Should at least contain "arm,sbsa-gwdt".
+
+- reg: Each entry specifies the base physical 64-bit address of a register
+  frame and the 64-bit length of that frame; currently, two frames must be
+  defined, in this order:
+  1: Watchdog control frame
+  2: Refresh frame.
+
+- interrupts: At least one interrupt must be defined that will be used as
+  the WS0 interrupt.  A WS1 interrupt definition can be provided, but is
+  optional.  The interrupts must be defined in this order:
+  1: WS0 interrupt
+  2: WS1 interrupt
+
+Optional properties
+- timeout-sec: To use a timeout value that is different from the driver
+  default values, use this property.  If used, at least one timeout value
+  (in seconds) must be provided.  A second optional timeout value (in
+  seconds) may also be provided and will be used as the pre-timeout value,
+  if it is given.
+
+  There are two possible sources for driver default timeout values:
+  (1) the driver contains hard-coded default values, or
+  (2) module parameters can be given when the module is loaded
+
+  If timeout/pretimeout values are provided when the module loads, they
+  will take priority.  Second priority will be the timeout-sec from DTB,
+  and third the hard-coded driver values.
+
+Example for FVP Foundation Model v8:
+
+watchdog@2a440000 {
+	compatible = "arm,sbsa-gwdt";
+	reg = <0x0 0x2a440000 0 0x1000>,
+	      <0x0 0x2a450000 0 0x1000>;
+	interrupts = <0 27 4>;
+	timeout-sec = <60 30>;
+};
diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt
index 9f9ec9f..e62c8c4 100644
--- a/Documentation/watchdog/watchdog-parameters.txt
+++ b/Documentation/watchdog/watchdog-parameters.txt
@@ -284,6 +284,12 @@ sbc_fitpc2_wdt:
 margin: Watchdog margin in seconds (default 60s)
 nowayout: Watchdog cannot be stopped once started
 -------------------------------------------------
+sbsa_gwdt:
+timeout: Watchdog timeout in seconds. (default 60s)
+pretimeout: Watchdog pretimeout in seconds. (default 30s)
+nowayout: Watchdog cannot be stopped once started
+	(default=kernel config parameter)
+-------------------------------------------------
 sc1200wdt:
 isapnp: When set to 0 driver ISA PnP support will be disabled (default=1)
 io: io port
-- 
2.4.3