dmaengine: add device tree binding documentation for the nbpfaxi driver

The nbpfaxi dmaengine driver doesn't define any new bindings, it only
uses standard dmaengine bindings and defines 3 flags for the 3rd parameter
of the "dmas" property.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Guennadi Liakhovetski 2014-07-19 12:48:45 +02:00 committed by Vinod Koul
parent ed64610f29
commit 94c7b6fc7c
2 changed files with 81 additions and 0 deletions

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* Renesas "Type-AXI" NBPFAXI* DMA controllers
* DMA controller
Required properties
- compatible: must be one of
"renesas,nbpfaxi64dmac1b4"
"renesas,nbpfaxi64dmac1b8"
"renesas,nbpfaxi64dmac1b16"
"renesas,nbpfaxi64dmac4b4"
"renesas,nbpfaxi64dmac4b8"
"renesas,nbpfaxi64dmac4b16"
"renesas,nbpfaxi64dmac8b4"
"renesas,nbpfaxi64dmac8b8"
"renesas,nbpfaxi64dmac8b16"
- #dma-cells: must be 2: the first integer is a terminal number, to which this
slave is connected, the second one is flags. Flags is a bitmask
with the following bits defined:
#define NBPF_SLAVE_RQ_HIGH 1
#define NBPF_SLAVE_RQ_LOW 2
#define NBPF_SLAVE_RQ_LEVEL 4
Optional properties:
You can use dma-channels and dma-requests as described in dma.txt, although they
won't be used, this information is derived from the compatibility string.
Example:
dma: dma-controller@48000000 {
compatible = "renesas,nbpfaxi64dmac8b4";
reg = <0x48000000 0x400>;
interrupts = <0 12 0x4
0 13 0x4
0 14 0x4
0 15 0x4
0 16 0x4
0 17 0x4
0 18 0x4
0 19 0x4>;
#dma-cells = <2>;
dma-channels = <8>;
dma-requests = <8>;
};
* DMA client
Required properties:
dmas and dma-names are required, as described in dma.txt.
Example:
#include <dt-bindings/dma/nbpfaxi.h>
...
dmas = <&dma 0 (NBPF_SLAVE_RQ_HIGH | NBPF_SLAVE_RQ_LEVEL)
&dma 1 (NBPF_SLAVE_RQ_HIGH | NBPF_SLAVE_RQ_LEVEL)>;
dma-names = "rx", "tx";

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/*
* Copyright (C) 2013-2014 Renesas Electronics Europe Ltd.
* Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*/
#ifndef DT_BINDINGS_NBPFAXI_H
#define DT_BINDINGS_NBPFAXI_H
/**
* Use "#dma-cells = <2>;" with the second integer defining slave DMA flags:
*/
#define NBPF_SLAVE_RQ_HIGH 1
#define NBPF_SLAVE_RQ_LOW 2
#define NBPF_SLAVE_RQ_LEVEL 4
#endif