dmaengine: at_hdmac: add FIFO configuration parameter to DMA DT binding

For most devices the FIFO configuration is the same i.e. when half FIFO size is
available/filled, a source/destination request is serviced. But USART devices
have to do it when there is enough space/data available to perform a single
AHB access so the ASAP configuration.

Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/Documentation/devicetree/bindings/dma/atmel-dma.txt b/Documentation/devicetree/bindings/dma/atmel-dma.txt
index c80e8a3402f0..c280a0e6f42d 100644
--- a/Documentation/devicetree/bindings/dma/atmel-dma.txt
+++ b/Documentation/devicetree/bindings/dma/atmel-dma.txt
@@ -24,8 +24,11 @@ The three cells in order are:
 1. A phandle pointing to the DMA controller.
 2. The memory interface (16 most significant bits), the peripheral interface
 (16 less significant bits).
-3. The peripheral identifier for the hardware handshaking interface. The
-identifier can be different for tx and rx.
+3. Parameters for the at91 DMA configuration register which are device
+dependant:
+  - bit 7-0: peripheral identifier for the hardware handshaking interface. The
+  identifier can be different for tx and rx.
+  - bit 11-8: FIFO configuration. 0 for half FIFO, 1 for ALAP, 1 for ASAP.
 
 Example: