[2/7] dt-bindings: bus: Add binding for the Allwinner MBUS controller

Commit Message

Maxime Ripard April 3, 2018, 1:29 p.m. UTC

The MBUS controller drives the MBUS that other devices in the SoC will
use to perform DMA. It also has a register interface that allows to
monitor and control the bandwidth and priorities for masters on that
bus.

Signed-off-by: Maxime Ripard <[e-mail]>
---
 Documentation/devicetree/bindings/sunxi-mbus.txt | 35 +++++++++++++++++-
 1 file changed, 35 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/sunxi-mbus.txt

Patch

diff --git a/Documentation/devicetree/bindings/sunxi-mbus.txt b/Documentation/devicetree/bindings/sunxi-mbus.txt
new file mode 100644
index 000000000000..436df0cac9d0
--- /dev/null
+++ b/Documentation/devicetree/bindings/sunxi-mbus.txt
@@ -0,0 +1,35 @@ 
+Allwinner Memory Bus (MBUS) controller
+
+The MBUS controller drives the MBUS that other devices in the SoC will
+use to perform DMA. It also has a register interface that allows to
+monitor and control the bandwidth and priorities for masters on that
+bus.
+
+Required properties:
+ - compatible: Must be one of:
+	- allwinner,sun5i-a13-mbus
+ - reg: Offset and length of the register set for the controller
+ - clocks: phandle to the clock driving the controller
+ - dma-ranges: see booting-without-of.txt
+ - #dma-parent-cells: Must be one, with the argument being the MBUS port
+   ID
+
+Each device having to perform their DMA through the MBUS must have the
+dma-parent property set to the MBUS controller, as documented in
+booting-without-of.txt.
+
+Example:
+
+mbus: dram-controller@1c01000 {
+	compatible = "allwinner,sun5i-a13-mbus";
+	reg = <0x01c01000 0x1000>;
+	clocks = <&ccu CLK_MBUS>;
+	dma-ranges = <0x00000000 0x40000000 0x20000000>;
+	#dma-parent-cells = <1>;
+};
+
+fe0: display-frontend@1e00000 {
+	compatible = "allwinner,sun5i-a13-display-frontend";
+	...
+	dma-parent = <&mbus 19>;
+};