diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt b/Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt index 63a48928f3a8..b152a75dceae 100644 --- a/Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt +++ b/Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt @@ -2,9 +2,10 @@ Texas Instruments DMA Crossbar (DMA request router) Required properties: - compatible: "ti,dra7-dma-crossbar" for DRA7xx DMA crossbar + "ti,am335x-edma-crossbar" for AM335x and AM437x - reg: Memory map for accessing module -- #dma-cells: Should be set to <1>. - Clients should use the crossbar request number (input) +- #dma-cells: Should be set to to match with the DMA controller's dma-cells + for ti,dra7-dma-crossbar and <3> for ti,am335x-edma-crossbar. - dma-requests: Number of DMA requests the crossbar can receive - dma-masters: phandle pointing to the DMA controller @@ -14,6 +15,15 @@ The DMA controller node need to have the following poroperties: Optional properties: - ti,dma-safe-map: Safe routing value for unused request lines +Notes: +When requesting channel via ti,dra7-dma-crossbar, the DMA clinet must request +the DMA event number as crossbar ID (input to the DMA crossbar). + +For ti,am335x-edma-crossbar: the meaning of parameters of dmas for clients: +dmas = <&edma_xbar 12 0 1>; where <12> is the DMA request number, <0> is the TC +the event should be assigned and <1> is the mux selection for in the crossbar. +When mux 0 is used the DMA channel can be requested directly from edma node. + Example: /* DMA controller */ @@ -47,6 +57,7 @@ uart1: serial@4806a000 { ti,hwmods = "uart1"; clock-frequency = <48000000>; status = "disabled"; + /* Requesting crossbar input 49 and 50 */ dmas = <&sdma_xbar 49>, <&sdma_xbar 50>; dma-names = "tx", "rx"; }; |