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-rw-r--r-- | Documentation/devicetree/bindings/dma/st,stm32-dma.yaml | 116 |
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diff --git a/Documentation/devicetree/bindings/dma/st,stm32-dma.yaml b/Documentation/devicetree/bindings/dma/st,stm32-dma.yaml new file mode 100644 index 000000000..55faab6a4 --- /dev/null +++ b/Documentation/devicetree/bindings/dma/st,stm32-dma.yaml @@ -0,0 +1,116 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/dma/st,stm32-dma.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: STMicroelectronics STM32 DMA Controller bindings + +description: | + 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. + DMA clients connected to the STM32 DMA controller must use the format + described in the dma.txt file, using a four-cell specifier for each + channel: a phandle to the DMA controller plus the following four integer cells: + 1. The channel id + 2. The request line number + 3. A 32bit mask specifying the DMA channel configuration which are device + dependent: + -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 + 4. A 32bit bitfield value specifying DMA features which are device dependent: + -bit 0-1: DMA FIFO threshold selection + 0x0: 1/4 full FIFO + 0x1: 1/2 full FIFO + 0x2: 3/4 full FIFO + 0x3: full FIFO + -bit 2: DMA direct mode + 0x0: FIFO mode with threshold selectable with bit 0-1 + 0x1: Direct mode: each DMA request immediately initiates a transfer + from/to the memory, FIFO is bypassed. + -bit 4: alternative DMA request/acknowledge protocol + 0x0: Use standard DMA ACK management, where ACK signal is maintained + up to the removal of request and transfer completion + 0x1: Use alternative DMA ACK management, where ACK de-assertion does + not wait for the de-assertion of the REQuest, ACK is only managed + by transfer completion. This must only be used on channels + managing transfers for STM32 USART/UART. + + +maintainers: + - Amelie Delaunay <amelie.delaunay@foss.st.com> + +allOf: + - $ref: "dma-controller.yaml#" + +properties: + "#dma-cells": + const: 4 + + compatible: + const: st,stm32-dma + + reg: + maxItems: 1 + + clocks: + maxItems: 1 + + interrupts: + maxItems: 8 + description: Should contain all of the per-channel DMA + interrupts in ascending order with respect to the + DMA channel index. + + resets: + maxItems: 1 + + st,mem2mem: + $ref: /schemas/types.yaml#/definitions/flag + description: if defined, it indicates that the controller + supports memory-to-memory transfer + +required: + - compatible + - reg + - clocks + - interrupts + +unevaluatedProperties: false + +examples: + - | + #include <dt-bindings/interrupt-controller/arm-gic.h> + #include <dt-bindings/clock/stm32mp1-clks.h> + #include <dt-bindings/reset/stm32mp1-resets.h> + dma-controller@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-requests = <8>; + }; + +... |