On Sun, 16 Jan 2022 17:35:27 PST (-0800), zong.li@xxxxxxxxxx wrote:
Add dma-channels property, then we can determine how many channels there by device tree, rather than statically defines it in PDMA driver
Maybe "statically defining it" is better here?
Signed-off-by: Zong Li <zong.li@xxxxxxxxxx> --- .../devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml b/Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml index d32a71b975fe..3dbb8caefc17 100644 --- a/Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml +++ b/Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml @@ -34,6 +34,12 @@ properties: minItems: 1 maxItems: 8 + dma-channels: + description: For backwards-compatible, the default value is 4
Maybe "backwards-compatibility" is better here?
+ minimum: 1 + maximum: 4 + default: 4 + '#dma-cells': const: 1 @@ -50,6 +56,7 @@ examples: dma@3000000 { compatible = "sifive,fu540-c000-pdma";
IMO we should have a "sifive,pdma-1.0.0" (or whatever the versioning scheme ended up being) here, in addition to the SOC-specific DT entry. It's kind of odd to start extending the SOC-specific DT entry, as the whole idea there is to let us have an out in case we find future compatibility issues.
reg = <0x3000000 0x8000>; + dma-channels = <4>; interrupts = <23 24 25 26 27 28 29 30>; #dma-cells = <1>; };