Re: [PATCH v5 1/3] dt-bindings: Add dma-channels property and modify compatible

From: Palmer Dabbelt
Date: Thu Mar 03 2022 - 15:43:11 EST


On Sun, 06 Feb 2022 22:30:38 PST (-0800), zong.li@xxxxxxxxxx wrote:
Add dma-channels property, then we can determine how many channels there
by device tree, rather than statically defining it in PDMA driver.
In addition, we also modify the compatible for PDMA versioning scheme.

Signed-off-by: Zong Li <zong.li@xxxxxxxxxx>
Suggested-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
---
.../bindings/dma/sifive,fu540-c000-pdma.yaml | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml b/Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml
index 75ad898c59bc..92f410f54d72 100644
--- a/Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml
+++ b/Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml
@@ -25,7 +25,15 @@ description: |
properties:
compatible:
items:
- - const: sifive,fu540-c000-pdma
+ - enum:
+ - sifive,fu540-c000-pdma
+ - const: sifive,pdma0
+ description:
+ Should be "sifive,<chip>-pdma" and "sifive,pdma<version>".
+ Supported compatible strings are -
+ "sifive,fu540-c000-pdma" for the SiFive PDMA v0 as integrated onto the
+ SiFive FU540 chip resp and "sifive,pdma0" for the SiFive PDMA v0 IP block
+ with no chip integration tweaks.

reg:
maxItems: 1
@@ -34,6 +42,12 @@ properties:
minItems: 1
maxItems: 8

+ dma-channels:
+ description: For backwards-compatibility, the default value is 4
+ minimum: 1
+ maximum: 4
+ default: 4
+
'#dma-cells':
const: 1

@@ -48,8 +62,9 @@ additionalProperties: false
examples:
- |
dma@3000000 {
- compatible = "sifive,fu540-c000-pdma";
+ compatible = "sifive,fu540-c000-pdma", "sifive,pdma0";
reg = <0x3000000 0x8000>;
+ dma-channels = <4>;
interrupts = <23>, <24>, <25>, <26>, <27>, <28>, <29>, <30>;
#dma-cells = <1>;
};

Reviewed-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Acked-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>