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# 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
interrupts:
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