DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

Add binding documentation for the Qualcomm Hardware Mutex.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Acked-by: Kumar Gala <galak@codeaurora.org>
Reviewed-by: Andy Gross <agross@codeaurora.org>
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

diff --git a/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
new file mode 100644 (file)
index 0000000..4563f52
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
@@ -0,0 +1,39 @@
+Qualcomm Hardware Mutex Block:
+
+The hardware block provides mutexes utilized between different processors on
+the SoC as part of the communication protocol used by these processors.
+
+- compatible:
+       Usage: required
+       Value type: <string>
+       Definition: must be one of:
+                   "qcom,sfpb-mutex",
+                   "qcom,tcsr-mutex"
+
+- syscon:
+       Usage: required
+       Value type: <prop-encoded-array>
+       Definition: one cell containing:
+                   syscon phandle
+                   offset of the hwmutex block within the syscon
+                   stride of the hwmutex registers
+
+- #hwlock-cells:
+       Usage: required
+       Value type: <u32>
+       Definition: must be 1, the specified cell represent the lock id
+                   (hwlock standard property, see hwlock.txt)
+
+Example:
+
+       tcsr_mutex_block: syscon@fd484000 {
+               compatible = "syscon";
+               reg = <0xfd484000 0x2000>;
+       };
+
+       hwlock@fd484000 {
+               compatible = "qcom,tcsr-mutex";
+               syscon = <&tcsr_mutex_block 0 0x80>;
+
+               #hwlock-cells = <1>;
+       };