dt-bindings: dma: sprd,sc9860-dma: convert to YAML

Convert the Spreadtrum SC9860 DMA bindings to DT schema.

Changes during conversion:
- rename file to match compatible
- make interrupts optional, the AGCP DMA controller doesn't need it
- describe the optional ashb_eb clock for the AGCP DMA controller

Signed-off-by: Stanislav Jakubek <[e-mail]>
Reviewed-by: Rob Herring (Arm) <[e-mail]>
Link: https://lore.kernel.org/r/Zob1+kGW1xeBKehA@standask-GA-A55M-S2HP
Signed-off-by: Vinod Koul <[e-mail]>

Documentation/devicetree/bindings/dma/sprd,sc9860-dma.yaml

···
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dma/sprd,sc9860-dma.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Spreadtrum SC9860 DMA controller
+
+description: |
+  There are three DMA controllers: AP DMA, AON DMA and AGCP DMA. For AGCP
+  DMA controller, it can or do not request the IRQ, which will save
+  system power without resuming system by DMA interrupts if AGCP DMA
+  does not request the IRQ.
+
+maintainers:
+  - Orson Zhai <[e-mail]>
+  - Baolin Wang <[e-mail]>
+  - Chunyan Zhang <[e-mail]>
+
+properties:
+  compatible:
+    const: sprd,sc9860-dma
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    minItems: 1
+    items:
+      - description: DMA enable clock
+      - description: optional ashb_eb clock, only for the AGCP DMA controller
+
+  clock-names:
+    minItems: 1
+    items:
+      - const: enable
+      - const: ashb_eb
+
+  '#dma-cells':
+    const: 1
+
+  dma-channels:
+    const: 32
+
+  '#dma-channels':
+    const: 32
+    deprecated: true
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - '#dma-cells'
+  - dma-channels
+
+allOf:
+  - $ref: dma-controller.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/sprd,sc9860-clk.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    /* AP DMA controller */
+    dma-controller@20100000 {
+      compatible = "sprd,sc9860-dma";
+      reg = <0x20100000 0x4000>;
+      interrupts = <GIC_SPI 42 IRQ_TYPE_LEVEL_HIGH>;
+      clocks = <&apahb_gate CLK_DMA_EB>;
+      clock-names = "enable";
+      #dma-cells = <1>;
+      dma-channels = <32>;
+    };
+
+    /* AGCP DMA controller */
+    dma-controller@41580000 {
+      compatible = "sprd,sc9860-dma";
+      reg = <0x41580000 0x4000>;
+      clocks = <&agcp_gate CLK_AGCP_DMAAP_EB>,
+               <&agcp_gate CLK_AGCP_AP_ASHB_EB>;
+      clock-names = "enable", "ashb_eb";
+      #dma-cells = <1>;
+      dma-channels = <32>;
+    };
+...

Documentation/devicetree/bindings/dma/sprd-dma.txt

···
-* Spreadtrum DMA controller
-
-This binding follows the generic DMA bindings defined in dma.txt.
-
-Required properties:
-- compatible: Should be "sprd,sc9860-dma".
-- reg: Should contain DMA registers location and length.
-- interrupts: Should contain one interrupt shared by all channel.
-- #dma-cells: must be <1>. Used to represent the number of integer
-	cells in the dmas property of client device.
-- dma-channels : Number of DMA channels supported. Should be 32.
-- clock-names: Should contain the clock of the DMA controller.
-- clocks: Should contain a clock specifier for each entry in clock-names.
-
-Deprecated properties:
-- #dma-channels : Number of DMA channels supported. Should be 32.
-
-Example:
-
-Controller:
-apdma: dma-controller@20100000 {
-	compatible = "sprd,sc9860-dma";
-	reg = <0x20100000 0x4000>;
-	interrupts = <GIC_SPI 50 IRQ_TYPE_LEVEL_HIGH>;
-	#dma-cells = <1>;
-	dma-channels = <32>;
-	clock-names = "enable";
-	clocks = <&clk_ap_ahb_gates 5>;
-};
-
-
-Client:
-DMA clients connected to the Spreadtrum DMA controller must use the format
-described in the dma.txt file, using a two-cell specifier for each channel.
-The two cells in order are:
-1. A phandle pointing to the DMA controller.
-2. The slave id.
-
-spi0: spi@70a00000{
-	...
-	dma-names = "rx_chn", "tx_chn";
-	dmas = <&apdma 11>, <&apdma 12>;
-	...
-};