dt-bindings: dma: Add lpc32xx DMA mux binding

LPC32XX SoCs use pl080 dma controller which have few request signals
multiplexed between peripherals. This binding describes how devices can
use the multiplexed request signals.

Signed-off-by: Piotr Wojtaszczyk <piotr.wojtaszczyk@timesys.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240627150046.258795-3-piotr.wojtaszczyk@timesys.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>

Documentation/devicetree/bindings/dma/nxp,lpc3220-dmamux.yaml

@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dma/nxp,lpc3220-dmamux.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: DMA multiplexer for LPC32XX SoC (DMA request router)
+
+maintainers:
+  - J.M.B. Downing <jonathan.downing@nautel.com>
+  - Piotr Wojtaszczyk <piotr.wojtaszczyk@timesys.com>
+
+allOf:
+  - $ref: dma-router.yaml#
+
+properties:
+  compatible:
+    const: nxp,lpc3220-dmamux
+
+  reg:
+    maxItems: 1
+
+  dma-masters:
+    description: phandle to a dma node compatible with arm,pl080
+    maxItems: 1
+
+  "#dma-cells":
+    const: 3
+    description: |
+      First two cells same as for device pointed in dma-masters.
+      Third cell represents mux value for the request.
+
+required:
+  - compatible
+  - reg
+  - dma-masters
+
+additionalProperties: false
+
+examples:
+  - |
+    dma-router@7c {
+      compatible = "nxp,lpc3220-dmamux";
+      reg = <0x7c 0x8>;
+      dma-masters = <&dma>;
+      #dma-cells = <3>;
+    };
+
+...

MAINTAINERS

@@ -2428,6 +2428,7 @@ N:	lpc18xx
 
 ARM/LPC32XX SOC SUPPORT
 M:	Vladimir Zapolskiy <vz@mleia.com>
+M:	Piotr Wojtaszczyk <piotr.wojtaszczyk@timesys.com>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:	Maintained
 T:	git git://github.com/vzapolskiy/linux-lpc32xx.git
@@ -2440,6 +2441,14 @@ F:	drivers/usb/host/ohci-nxp.c
 F:	drivers/watchdog/pnx4008_wdt.c
 N:	lpc32xx
 
+LPC32XX DMAMUX SUPPORT
+M:	J.M.B. Downing <jonathan.downing@nautel.com>
+M:	Piotr Wojtaszczyk <piotr.wojtaszczyk@timesys.com>
+R:	Vladimir Zapolskiy <vz@mleia.com>
+L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
+S:	Maintained
+F:	Documentation/devicetree/bindings/dma/nxp,lpc3220-dmamux.yaml
+
 ARM/Marvell Dove/MV78xx0/Orion SOC support
 M:	Andrew Lunn <andrew@lunn.ch>
 M:	Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>