[PATCH v3 1/5] dt-bindings: Document the STM32 DMAMUX bindings

[Pierre-Yves MORDRET]

This patch adds the documentation of device tree bindings for the STM32
DMAMUX.

Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@xxxxxxxxx>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@xxxxxx>
---
 Version history:
    v3:
        * change compatible to st,stm32h7-dmamux to be mode Soc specific
        * add verbosity in dma-cells
    v2:
        * Move clock bindings from optional to mandatory one
        * Drop channelID bindings as managed dynamically from now on by
          DMAMUX driver.
---
---
 .../devicetree/bindings/dma/stm32-dmamux.txt       | 60 ++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/stm32-dmamux.txt

diff --git a/Documentation/devicetree/bindings/dma/stm32-dmamux.txt b/Documentation/devicetree/bindings/dma/stm32-dmamux.txt
new file mode 100644
index 0000000..abdb5ed
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/stm32-dmamux.txt
@@ -0,0 +1,60 @@
+STM32 DMA MUX (DMA request router)
+
+Required properties:
+- compatible:	"st,stm32h7-dmamux"
+- reg:		Memory map for accessing module
+- #dma-cells:	Should be set to <3>.
+		First parameter is request line number.
+		Second is DMA channel configuration
+		Third is Fifo threshold
+		For more details about the three cells, please see
+		stm32-dma.txt documentation binding file
+- dma-masters:	Phandle pointing to the DMA controller
+
+Optional properties:
+- dma-channels : Number of DMA channels supported.
+- dma-requests : Number of DMA requests supported.
+- resets: Reference to a reset controller asserting the DMA controller
+- clocks: Input clock of the DMAMUX instance.
+
+Example:
+
+/* DMA controller */
+dma2: dma-controller@40026400 {
+	compatible = "st,stm32-dma";
+	reg = <0x40026400 0x400>;
+	interrupts = <56>,
+		     <57>,
+		     <58>,
+		     <59>,
+		     <60>,
+		     <68>,
+		     <69>,
+		     <70>;
+	clocks = <&clk_hclk>;
+	#dma-cells = <4>;
+	st,mem2mem;
+	resets = <&rcc 150>;
+	st,dmamux;
+	dma-channels = <8>;
+};
+
+/* DMA mux */
+dmamux2: dma-router@40020820 {
+	compatible = "st,stm32h7-dmamux";
+	reg = <0x40020800 0x1c>;
+	#dma-cells = <3>;
+	dma-requests = <128>;
+	dma-masters = <&dma2>;
+};
+
+/* DMA client */
+usart1: serial@40011000 {
+	compatible = "st,stm32-usart", "st,stm32-uart";
+	reg = <0x40011000 0x400>;
+	interrupts = <37>;
+	clocks = <&clk_pclk2>;
+	dmas = <&dmamux2 41 0x414 0>,
+	       <&dmamux2 42 0x414 0>;
+	dma-names = "rx", "tx";
+};
-- 
2.7.4