bootcount: add a new driver with syscon as backend

The driver will use a syscon regmap as backend and supports both
16 and 32 size value. The value will be stored in the CPU's endianness.

Signed-off-by: Nandor Han <nandor.han@vaisala.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/doc/device-tree-bindings/bootcount-syscon.txt b/doc/device-tree-bindings/bootcount-syscon.txt
new file mode 100644
index 0000000000..e124f7b614
--- /dev/null
+++ b/doc/device-tree-bindings/bootcount-syscon.txt
@@ -0,0 +1,24 @@
+Bootcount Configuration
+This is the implementation of the feature as described in
+https://www.denx.de/wiki/DULG/UBootBootCountLimit.
+
+Required Properties:
+- compatible: must be "u-boot,bootcount-syscon".
+- syscon: reference to the syscon device used.
+- reg: contains address and size of the register and the location and size of the bootcount value.
+	   The driver supports a 4 bytes register length and 2 and 4 bytes bootcount value length.
+- reg-names: must be "syscon_reg", "offset";
+
+Example:
+	...
+	syscon0: syscon@0 {
+		compatible = "sandbox,syscon0";
+		reg = <0x10 16>;
+	};
+	...
+	bootcount@0 {
+		compatible = "u-boot,bootcount-syscon";
+		syscon = <&syscon0>;
+		reg = <0x0 0x04>, <0x0 0x04>;
+		reg-names = "syscon_reg", "offset";
+	};