st,stm32-dmamux¶

Description¶

These nodes are “dmamux” bus nodes.

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
   4. features: NOT USED by dmamux
 exemple for stm32wb55x
   dmamux1: dmamux@40020800 {
       compatible = "st,stm32-dmamux";
       ...
       dma-channels = <14>;
       dma-generators = <4>;
       dma-requests= <36>;
       status = "disabled";
       label = "DMAMUX_1";
      };
  for client SPI of stm32wb55x
   spi1: spi@40013000 {
       compatible = "st,stm32-spi";
       dmas = <&dmamux1 11 7 0x20440 0
       &dmamux1 1 6 0x20480 0>;
       dma-names = "tx", "rx";
      };

Properties¶

Properties not inherited from the base binding file.

Name	Type	Details
`#dma-cells`	`int`	Number of items to expect in a DMA specifier This property is required. Constant value: `4`
`dma-channels`	`int`	Number of DMAMUX output request channels supported by the controller This property is required.
`dma-generators`	`int`	Number of DMAMUX Request generator supported by the controller
`dma-requests`	`int`	Number of DMAMUX Peripheral Request Line inputs supported by the controller This property is required.

Properties inherited from the base binding file, which defines common properties that may be set on many nodes. Not all of these may apply to the “st,stm32-dmamux” compatible.

Name	Type	Details
`reg`	`array`	register space This property is required. See Important properties for more information.
`interrupts`	`array`	interrupts for device This property is required. See Important properties for more information.
`label`	`string`	Human readable string describing the device (used as device_get_binding() argument) This property is required. See Important properties for more information.
`status`	`string`	indicates the operational status of a device Legal values: `'ok'`, `'okay'`, `'disabled'`, `'reserved'`, `'fail'`, `'fail-sss'` See Important properties for more information.
`compatible`	`string-array`	compatible strings This property is required. See Important properties for more information.
`reg-names`	`string-array`	name of each register space
`interrupts-extended`	`compound`	extended interrupt specifier for device
`interrupt-names`	`string-array`	name of each interrupt
`interrupt-parent`	`phandle`	phandle to interrupt controller node
`clocks`	`phandle-array`	Clock gate information
`clock-names`	`string-array`	name of each clock
`#address-cells`	`int`	number of address cells in reg property
`#size-cells`	`int`	number of size cells in reg property
`dmas`	`phandle-array`	DMA channels specifiers
`dma-names`	`string-array`	Provided names of DMA channel specifiers
`io-channels`	`phandle-array`	IO channels specifiers
`io-channel-names`	`string-array`	Provided names of IO channel specifiers

Specifier cell names¶

dma cells: channel, slot, channel-config, features