| # Copyright (c) 2019, STMicroelectronics |
| # SPDX-License-Identifier: Apache-2.0 |
| |
| description: | |
| STM32 DMAMUX controller |
| |
| The STM32 DMAMUX is a direct memory access multiplexer |
| capable of supporting independent DMA channels. |
| DMAMUX clients connected to the STM32 DMA ultiplexer must use a two-cell specifier |
| for each dmamux channel: a phandle to the DMA multiplexer plus the following 2 integer cells: |
| 1. channel: the mux channel from 0 to <dma-channels> - 1 |
| 2. slot: the request line Multiplexer ID |
| 3. channel-config: A 32bit mask specifying the DMA channel configuration |
| which is device dependent: |
| -bit 6-7 : Direction (see dma.h) |
| 0x0: MEM to MEM |
| 0x1: MEM to PERIPH |
| 0x2: PERIPH to MEM |
| 0x3: reserved for PERIPH to PERIPH |
| -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 11-12 : Peripheral data size |
| 0x0: Byte (8 bits) |
| 0x1: Half-word (16 bits) |
| 0x2: Word (32 bits) |
| 0x3: reserved |
| -bit 13-14 : Memory data size |
| 0x0: Byte (8 bits) |
| 0x1: Half-word (16 bits) |
| 0x2: Word (32 bits) |
| 0x3: reserved |
| -bit 15: Peripheral Increment Offset Size not USED for DMA V2 |
| 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 |
| example for stm32wb55x |
| dmamux1: dmamux@40020800 { |
| compatible = "st,stm32-dmamux"; |
| ... |
| dma-channels = <14>; |
| dma-generators = <4>; |
| dma-requests= <36>; |
| status = "disabled"; |
| }; |
| for client SPI of stm32wb55x |
| spi1: spi@40013000 { |
| compatible = "st,stm32-spi"; |
| dmas = <&dmamux1 11 7 0x20440 |
| &dmamux1 1 6 0x20480>; |
| dma-names = "tx", "rx"; |
| }; |
| |
| compatible: "st,stm32-dmamux" |
| |
| include: dmamux-controller.yaml |
| |
| properties: |
| reg: |
| required: true |
| |
| "#dma-cells": |
| const: 3 |
| |
| # Parameter syntax of stm32 follows the dma client dts syntax |
| # in the Linux kernel declared in |
| # https://git.kernel.org/pub/scm/linux/kernel/git/devicetree/devicetree-rebasing.git/plain/Bindings/dma/st,stm32-dmamux.yaml |
| |
| dma-cells: |
| - channel |
| - slot |
| - channel-config |
