[PATCH 1/2] dt: dma: Add DT binding document for jz4780-dma

Zubair Lutfullah Kakakhel
2015-01-29T12:20:39Z

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>
---
.../devicetree/bindings/dma/jz4780-dma.txt | 59 ++++++++++++++++++++++
1 file changed, 59 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..0e46056
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/jz4780-dma.txt
@@ -0,0 +1,59 @@
+* 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.
+- clocks: Should contain a clock specifier for the JZ4780 PDMA clock.
+- #dma-cells: Must be <3>. 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>;
+
+ interrupts = <10>;
+
+ clocks = <&cgu JZ4780_CLK_PDMA>;
+
+ #dma-cells = <3>;
+
+ ingenic,reserved-channels = <0x3>;
+};
+
+DMA clients must use the format described in dma.txt, giving a phandle to the
+DMA controller plus the following 3 integer cells:
+
+1. Transmit request type: The DMA request type for transfers to the device on
+ the allocated channel, as defined in the SoC documentation. If set to 0,
+ transfers to the device will not be allowed on the channel.
+
+2. Receive request type: The DMA request type for transfers from the device on
+ the allocated channel, as defined in the SoC documentation. If set to 0,
+ transfers from the device will not be allowed on the channel.
+
+3. 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 0 0xffffffff
+ &dma 0 0x15 0xffffffff>;
+ dma-names = "tx", "rx";
+ ...
+};
--
1.9.1