[PATCH_V4 1/3] dt-bindings: dma: Add binding for jz4780-dma

Zubair Lutfullah Kakakhel
2015-03-18T16:16:35Z

From: Alex Smith <alex.smith@imgtec.com>

Add device tree bindings for the DMA controller on JZ4780 SoCs, used by
the dma-jz4780 driver.

Signed-off-by: Alex Smith <alex.smith@imgtec.com>
Signed-off-by: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>

---
V3 -> V4
None

V3 -> V2
Changed binding.
Used to be 3 DMA cells required. <&dma TX_type RX_type Reserved>
Now 2 DMA cells are required. <&dma Transfer_type Reserved>

This is more common in DMA bindings.
And I couldn't figure any reason that 3 cells were used.

V1 -> V2 None
---
.../devicetree/bindings/dma/jz4780-dma.txt | 56 ++++++++++++++++++++++
1 file changed, 56 insertions(+)
create mode 100644 Documentation/devicetree/bindings/dma/jz4780-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/jz4780-dma.txt b/Documentation/devicetree/bindings/dma/jz4780-dma.txt
new file mode 100644
index 0000000..f25feee
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/jz4780-dma.txt
@@ -0,0 +1,56 @@
+* Ingenic JZ4780 DMA Controller
+
+Required properties:
+
+- compatible: Should be "ingenic,jz4780-dma"
+- reg: Should contain the DMA controller registers location and length.
+- interrupts: Should contain the interrupt specifier of the DMA controller.
+- interrupt-parent: Should be the phandle of the interrupt controller that
+- clocks: Should contain a clock specifier for the JZ4780 PDMA clock.
+- #dma-cells: Must be <2>. Number of integer cells in the dmas property of
+ DMA clients (see below).
+
+Optional properties:
+
+- ingenic,reserved-channels: Bitmask of channels to reserve for devices that
+ need a specific channel. These channels will only be assigned when explicitly
+ requested by a client. The primary use for this is channels 0 and 1, which
+ can be configured to have special behaviour for NAND/BCH when using
+ programmable firmware.
+
+Example:
+
+dma: dma@13420000 {
+ compatible = "ingenic,jz4780-dma";
+ reg = <0x13420000 0x10000>;
+
+ interrupt-parent = <&intc>;
+ interrupts = <10>;
+
+ clocks = <&cgu JZ4780_CLK_PDMA>;
+
+ #dma-cells = <2>;
+
+ ingenic,reserved-channels = <0x3>;
+};
+
+DMA clients must use the format described in dma.txt, giving a phandle to the
+DMA controller plus the following 2 integer cells:
+
+1. Request type: The DMA request type for transfers to/from the device on
+ the allocated channel, as defined in the SoC documentation.
+
+2. Channel: If set to 0xffffffff, any available channel will be allocated for
+ the client. Otherwise, the exact channel specified will be used. The channel
+ should be reserved on the DMA controller using the ingenic,reserved-channels
+ property.
+
+Example:
+
+uart0: serial@10030000 {
+ ...
+ dmas = <&dma 0x14 0xffffffff
+ &dma 0x15 0xffffffff>;
+ dma-names = "tx", "rx";
+ ...
+};
--
1.9.1