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dt-bindings: dma: ingenic: Support #dma-cells = <3>

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Extend the binding to support specifying a different request type for
each direction.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20211206174259.68133-3-paul@crapouillou.net
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Paul Cercueil 2021-12-06 17:42:55 +00:00 committed by Vinod Koul
parent e0699a7595
commit dafa79a10e
1 changed files with 10 additions and 4 deletions
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14
Documentation/devicetree/bindings/dma/ingenic,dma.yaml
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@ -44,13 +44,19 @@ properties:
maxItems: 1
"#dma-cells":
const: 2
enum: [2, 3]
description: >
DMA clients must use the format described in dma.txt, giving a phandle
to the DMA controller plus the following 2 integer cells:
to the DMA controller plus the following integer cells:
- Request type: The DMA request type for transfers to/from the
device on the allocated channel, as defined in the SoC documentation.
- Request type: The DMA request type specifies the device endpoint that
will be the source or destination of the DMA transfer.
If "#dma-cells" is 2, the request type is a single cell, and the
direction will be unidirectional (either RX or TX but not both).
If "#dma-cells" is 3, the request type has two cells; the first
one corresponds to the host to device direction (TX), the second one
corresponds to the device to host direction (RX). The DMA channel is
then bidirectional.
- Channel: If set to 0xffffffff, any available channel will be allocated
for the client. Otherwise, the exact channel specified will be used.