dmaengine: add device tree binding documentation for the nbpfaxi driver

The nbpfaxi dmaengine driver doesn't define any new bindings, it only
uses standard dmaengine bindings and defines 3 flags for the 3rd parameter
of the "dmas" property.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/dma/nbpfaxi.txt b/Documentation/devicetree/bindings/dma/nbpfaxi.txt
new file mode 100644
index 000000000000..d5e2522b9ec1
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/nbpfaxi.txt
@@ -0,0 +1,61 @@
+* Renesas "Type-AXI" NBPFAXI* DMA controllers
+
+* DMA controller
+
+Required properties
+
+- compatible:   must be one of
+                "renesas,nbpfaxi64dmac1b4"
+                "renesas,nbpfaxi64dmac1b8"
+                "renesas,nbpfaxi64dmac1b16"
+                "renesas,nbpfaxi64dmac4b4"
+                "renesas,nbpfaxi64dmac4b8"
+                "renesas,nbpfaxi64dmac4b16"
+                "renesas,nbpfaxi64dmac8b4"
+                "renesas,nbpfaxi64dmac8b8"
+                "renesas,nbpfaxi64dmac8b16"
+- #dma-cells:   must be 2: the first integer is a terminal number, to which this
+                slave is connected, the second one is flags. Flags is a bitmask
+                with the following bits defined:
+
+#define NBPF_SLAVE_RQ_HIGH      1
+#define NBPF_SLAVE_RQ_LOW       2
+#define NBPF_SLAVE_RQ_LEVEL     4
+
+Optional properties:
+
+You can use dma-channels and dma-requests as described in dma.txt, although they
+won't be used, this information is derived from the compatibility string.
+
+Example:
+
+        dma: dma-controller@48000000 {
+                compatible = "renesas,nbpfaxi64dmac8b4";
+                reg = <0x48000000 0x400>;
+                interrupts = <0 12 0x4
+                              0 13 0x4
+                              0 14 0x4
+                              0 15 0x4
+                              0 16 0x4
+                              0 17 0x4
+                              0 18 0x4
+                              0 19 0x4>;
+                #dma-cells = <2>;
+                dma-channels = <8>;
+                dma-requests = <8>;
+        };
+
+* DMA client
+
+Required properties:
+
+dmas and dma-names are required, as described in dma.txt.
+
+Example:
+
+#include <dt-bindings/dma/nbpfaxi.h>
+
+...
+                dmas = <&dma 0 (NBPF_SLAVE_RQ_HIGH | NBPF_SLAVE_RQ_LEVEL)
+                        &dma 1 (NBPF_SLAVE_RQ_HIGH | NBPF_SLAVE_RQ_LEVEL)>;
+                dma-names = "rx", "tx";