[PATCH v2 1/4] dt-bindings: Document the STM32 DMA bindings

M'boumba Cedric Madianga
2015-10-13T14:00:45Z

This patch adds documentation of device tree bindings for the STM32 dma
controller.

Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
---
.../devicetree/bindings/dma/stm32-dma.txt | 98 ++++++++++++++++++++++
1 file changed, 98 insertions(+)
create mode 100644 Documentation/devicetree/bindings/dma/stm32-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/stm32-dma.txt b/Documentation/devicetree/bindings/dma/stm32-dma.txt
new file mode 100644
index 0000000..9ce0d49
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/stm32-dma.txt
@@ -0,0 +1,98 @@
+* STMicroelectronics STM32 DMA controller
+
+The STM32 DMA is a general-purpose direct memory access controller capable of
+supporting 8 independent DMA channels. Each channel can have up to 8 requests.
+
+Required properties:
+- compatible: Should be "st,stm32-dma"
+- reg: Should contain DMA registers location and length. This should include
+ all of the per-channel registers.
+- interrupts: Should contain all of the per-channel DMA interrupts.
+- clocks: Should contain the input clock of the DMA instance.
+- #dma-cells : Must be <4>. See DMA client paragraph for more details.
+
+Optional properties:
+- resets: Reference to a reset controller asserting the DMA controller
+- st,mem2mem: boolean; if defined, it indicates that the controller supports
+ memory-to-memory transfer
+
+Example:
+
+ dma2: dma-controller at 40026400 {
+ compatible = "st,stm32-dma";
+ reg = <0x40026400 0x400>;
+ interrupts = <56>,
+ <57>,
+ <58>,
+ <59>,
+ <60>,
+ <68>,
+ <69>,
+ <70>;
+ clocks = <&clk_hclk>;
+ #dma-cells = <4>;
+ st,mem2mem;
+ resets = <&rcc 150>;
+ };
+
+* DMA client
+
+Required properties:
+- dmas: Comma separated list of dma channel requests
+- dma-names: Names of the aforementioned requested channels
+
+Each dmas request consists of 5 cells:
+1. A phandle pointing to the STM32 DMA controller
+2. The channel id
+3. The request line number
+4. A 32bit mask specifying the DMA channel configuration
+ -bit 1: Direct Mode Error Interrupt
+ 0x0: disabled
+ 0x1: enabled
+ -bit 2: Transfer Error Interrupt
+ 0x0: disabled
+ 0x1: enabled
+ -bit 3: Half Transfer Mode Error Interrupt
+ 0x0: disabled
+ 0x1: enabled
+ -bit 4: Transfer Complete Interrupt
+ 0x0: disabled
+ 0x1: enabled
+ -bit 9: Peripheral Increment Address
+ 0x0: no address increment between transfers
+ 0x1: increment address between transfers
+ -bit 10: Memory Increment Address
+ 0x0: no address increment between transfers
+ 0x1: increment address between transfers
+ -bit 15: Peripheral Increment Offset Size
+ 0x0: offset size is linked to the peripheral bus width
+ 0x1: offset size is fixed to 4 (32-bit alignment)
+ -bit 16-17: Priority level
+ 0x0: low
+ 0x1: medium
+ 0x2: high
+ 0x3: very high
+5. A 32bit mask specifying the DMA FIFO configuration
+ -bit 0-1: Fifo threshold
+ 0x0: 1/4 full FIFO
+ 0x1: 1/2 full FIFO
+ 0x2: 3/4 full FIFO
+ 0x3:full FIFO
+ -bit 2: Direct mode
+ 0x0: enabled
+ 0x1: disabled
+ -bit 7: FIFO Error Interrupt
+ 0x0: disabled
+ 0x1: enabled
+
+Example:
+
+ usart1: serial at 40011000 {
+ compatible = "st,stm32-usart", "st,stm32-uart";
+ reg = <0x40011000 0x400>;
+ interrupts = <37>;
+ clocks = <&clk_pclk2>;
+ dmas = <&dma2 2 4 0x20610 0x3>,
+ <&dma2 7 5 0x20610 0x3>;
+ dma-names = "rx", "tx";
+ };
--
1.9.1