dt-bindings: dmaengine: xilinx_dma: Add binding for Xilinx MCDMA IP

Add devicetree binding for Xilinx AXI Multichannel Direct Memory Access
(AXI MCDMA) IP. The AXI MCDMA provides high-bandwidth direct memory
access between memory and AXI4-Stream target peripherals. The AXI MCDMA
core provides a scatter-gather interface with multiple channel support
with independent configuration.
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1571763622-29281-4-git-send-email-radhey.shyam.pandey@xilinx.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/dma/xilinx/xilinx_dma.txt

@@ -11,11 +11,16 @@ is to receive from the device.
 Xilinx AXI CDMA engine, it does transfers between memory-mapped source
 address and a memory-mapped destination address.
 
+Xilinx AXI MCDMA engine, it does transfer between memory and AXI4 stream
+target devices. It can be configured to have up to 16 independent transmit
+and receive channels.
+
 Required properties:
 - compatible: Should be one of-
 		"xlnx,axi-vdma-1.00.a"
 		"xlnx,axi-dma-1.00.a"
 		"xlnx,axi-cdma-1.00.a"
+		"xlnx,axi-mcdma-1.00.a"
 - #dma-cells: Should be <1>, see "dmas" property below
 - reg: Should contain VDMA registers location and length.
 - xlnx,addrwidth: Should be the vdma addressing size in bits(ex: 32 bits).
@@ -31,7 +36,7 @@ Required properties:
 			   "m_axis_mm2s_aclk", "s_axis_s2mm_aclk"
 	For CDMA:
 	Required elements: "s_axi_lite_aclk", "m_axi_aclk"
-	For AXIDMA:
+	For AXIDMA and MCDMA:
 	Required elements: "s_axi_lite_aclk"
 	Optional elements: "m_axi_mm2s_aclk", "m_axi_s2mm_aclk",
 			   "m_axi_sg_aclk"
@@ -39,7 +44,7 @@ Required properties:
 Required properties for VDMA:
 - xlnx,num-fstores: Should be the number of framebuffers as configured in h/w.
 
-Optional properties for AXI DMA:
+Optional properties for AXI DMA and MCDMA:
 - xlnx,sg-length-width: Should be set to the width in bits of the length
 	register as configured in h/w. Takes values {8...26}. If the property
 	is missing or invalid then the default value 23 is used. This is the
@@ -56,8 +61,8 @@ Required child node properties:
 	For VDMA: It should be either "xlnx,axi-vdma-mm2s-channel" or
 	"xlnx,axi-vdma-s2mm-channel".
 	For CDMA: It should be "xlnx,axi-cdma-channel".
-	For AXIDMA: It should be either "xlnx,axi-dma-mm2s-channel" or
-	"xlnx,axi-dma-s2mm-channel".
+	For AXIDMA and MCDMA: It should be either "xlnx,axi-dma-mm2s-channel"
+	or "xlnx,axi-dma-s2mm-channel".
 - interrupts: Should contain per channel VDMA interrupts.
 - xlnx,datawidth: Should contain the stream data width, take values
 	{32,64...1024}.
@@ -70,6 +75,8 @@ Optional child node properties for VDMA:
 	enabled/disabled in hardware.
 - xlnx,enable-vert-flip: Tells vertical flip is
 	enabled/disabled in hardware(S2MM path).
+Optional child node properties for MCDMA:
+- dma-channels: Number of dma channels in child node.
 
 Example:
 ++++++++