Re: [PATCH v4 1/3] dt-bindings: dma: fsl-edma: add dma-channel-mask property description
From: Frank Li <Frank.li@nxp.com>
Date: 2026-02-11 15:34:49
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imx, linux-arm-kernel, lkml
On Wed, Feb 11, 2026 at 05:28:24PM +0800, Joy Zou wrote:
Add documentation for the dma-channel-mask property in the fsl-edma binding. This property uses an inverted bit definition: bit value 0 indicates the channel is available, while bit value 1 indicates unavailable. That was already used widely for i.MX8, i.MX9. Correcting the definition will break backward compatibility. This reversal only impacts the eDMA dts node and driver, and doesn't impact DMA consumer. Therefore, keep the inverted definition. Also add a note at the top of the binding to highlight this inverted definition to prevent confusion. Signed-off-by: Joy Zou <redacted> ---
Reviewed-by: Frank Li <Frank.Li@nxp.com>
quoted hunk ↗ jump to hunk
Documentation/devicetree/bindings/dma/fsl,edma.yaml | 9 +++++++++ 1 file changed, 9 insertions(+)diff --git a/Documentation/devicetree/bindings/dma/fsl,edma.yaml b/Documentation/devicetree/bindings/dma/fsl,edma.yaml index fa4248e2f1b9cecd00f1535744bfe6d9ecdba613..f609038e35ae1836b89c5b4d8a095b15a882fb87 100644 --- a/Documentation/devicetree/bindings/dma/fsl,edma.yaml +++ b/Documentation/devicetree/bindings/dma/fsl,edma.yaml@@ -12,6 +12,9 @@ description: | DMAMUX0 and DMAMUX1, specific DMA request source can only be multiplexed by any channel of certain group, DMAMUX0 or DMAMUX1, but not both. + This binding has an inverted dma-channel-mask definition compared to + the common DMA binding for historical reasons. + maintainers: - Peng Fan <peng.fan@nxp.com>@@ -95,6 +98,12 @@ properties: eDMA are implemented in big endian mode, otherwise in little mode. type: boolean + dma-channel-mask: + description: | + Bitmask of available DMA channels (inverted definition). + Bit semantics: 0 means channel available, 1 means channel unavailable + default: 0 + required: - "#dma-cells" - compatible --2.37.1