X-Git-Url: http://git.monstr.eu/?p=linux-2.6-microblaze.git;a=blobdiff_plain;f=Documentation%2Fdevicetree%2Fbindings%2Fdma%2Fst%2Cstm32-dma.yaml;h=4bf676fd25dcf40942d2b9c63e664c690c0162a2;hp=2a5325f480f69f7e1b629730bb0881191f962670;hb=fdfc346302a7b63e3d5b9168be74bb12b1975999;hpb=0461a1ae98bc3045492333bebf6e79d4e859d3a1

diff --git a/Documentation/devicetree/bindings/dma/st,stm32-dma.yaml b/Documentation/devicetree/bindings/dma/st,stm32-dma.yaml
index 2a5325f480f6..4bf676fd25dc 100644
--- a/Documentation/devicetree/bindings/dma/st,stm32-dma.yaml
+++ b/Documentation/devicetree/bindings/dma/st,stm32-dma.yaml
@@ -40,6 +40,13 @@ description: |
          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: