dt-bindings: serial: snps-dw-apb-uart: Switch dma-names order

Commit 370f696e4474 ("dt-bindings: serial: snps-dw-apb-uart: add dma &
dma-names properties") documented dma-names property to handle Allwinner
D1 dtbs_check warnings, but relies on the rx->tx ordering, which is the
reverse of what a different board expects:

  rk3326-odroid-go2.dtb: serial@ff030000: dma-names:0: 'rx' was expected

A quick and incomplete check shows the inconsistency is present in many
other DTS files:

$ git grep -A10 snps,dw-apb-uart | grep dma-names | sort -u
arch/arm64/boot/dts/rockchip/px30.dtsi-         dma-names = "tx", "rx";
arch/arm64/boot/dts/rockchip/rk3328.dtsi-       dma-names = "tx", "rx";
arch/arm64/boot/dts/rockchip/rk3588s.dtsi-      dma-names = "tx", "rx";
arch/arm/boot/dts/rk3066a.dtsi-                 dma-names = "tx", "rx";
arch/arm/boot/dts/rk3128.dtsi-                  dma-names = "tx", "rx";
arch/arm/boot/dts/rk3288.dtsi-                  dma-names = "tx", "rx";
arch/arm/boot/dts/rv1126.dtsi-                  dma-names = "tx", "rx";
arch/arm/boot/dts/socfpga.dtsi-                 dma-names = "tx", "rx";
arch/arm/boot/dts/sun6i-a31.dtsi-               dma-names = "rx", "tx";
arch/arm/boot/dts/sun8i-a23-a33.dtsi-           dma-names = "rx", "tx";
arch/arm/boot/dts/sun8i-v3s.dtsi-               dma-names = "rx", "tx";
arch/arm/boot/dts/sunxi-h3-h5.dtsi-             dma-names = "rx", "tx";
arch/riscv/boot/dts/allwinner/sunxi-d1s-t113.dtsi-  dma-names = "rx", "tx";

The initial proposed solution was to allow a flexible dma-names order in
the binding, due to potential ABI breakage concerns after fixing the DTS
files. But luckily the Allwinner boards are not really affected, since
all of them are using a shared DMA channel for rx and tx:

$ git grep -A10 snps,dw-apb-uart | grep 'sun.*dmas' | sort -u
arch/arm/boot/dts/sun6i-a31.dtsi-       dmas = <&dma 10>, <&dma 10>;
arch/arm/boot/dts/sun6i-a31.dtsi-       dmas = <&dma 22>, <&dma 22>;
arch/arm/boot/dts/sun6i-a31.dtsi-       dmas = <&dma 6>, <&dma 6>;
arch/arm/boot/dts/sun6i-a31.dtsi-       dmas = <&dma 7>, <&dma 7>;
arch/arm/boot/dts/sun6i-a31.dtsi-       dmas = <&dma 8>, <&dma 8>;
arch/arm/boot/dts/sun6i-a31.dtsi-       dmas = <&dma 9>, <&dma 9>;
arch/arm/boot/dts/sun8i-a23-a33.dtsi-   dmas = <&dma 10>, <&dma 10>;
arch/arm/boot/dts/sun8i-a23-a33.dtsi-   dmas = <&dma 6>, <&dma 6>;
arch/arm/boot/dts/sun8i-a23-a33.dtsi-   dmas = <&dma 7>, <&dma 7>;
arch/arm/boot/dts/sun8i-a23-a33.dtsi-   dmas = <&dma 8>, <&dma 8>;
arch/arm/boot/dts/sun8i-a23-a33.dtsi-   dmas = <&dma 9>, <&dma 9>;
arch/arm/boot/dts/sun8i-v3s.dtsi-       dmas = <&dma 6>, <&dma 6>;
arch/arm/boot/dts/sun8i-v3s.dtsi-       dmas = <&dma 7>, <&dma 7>;
arch/arm/boot/dts/sun8i-v3s.dtsi-       dmas = <&dma 8>, <&dma 8>;
arch/arm/boot/dts/sunxi-h3-h5.dtsi-     dmas = <&dma 6>, <&dma 6>;
arch/arm/boot/dts/sunxi-h3-h5.dtsi-     dmas = <&dma 7>, <&dma 7>;
arch/arm/boot/dts/sunxi-h3-h5.dtsi-     dmas = <&dma 8>, <&dma 8>;
arch/arm/boot/dts/sunxi-h3-h5.dtsi-     dmas = <&dma 9>, <&dma 9>;
arch/riscv/boot/dts/allwinner/sunxi-d1s-t113.dtsi-  dmas = <&dma 14>, <&dma 14>;
arch/riscv/boot/dts/allwinner/sunxi-d1s-t113.dtsi-  dmas = <&dma 15>, <&dma 15>;
arch/riscv/boot/dts/allwinner/sunxi-d1s-t113.dtsi-  dmas = <&dma 16>, <&dma 16>;
arch/riscv/boot/dts/allwinner/sunxi-d1s-t113.dtsi-  dmas = <&dma 17>, <&dma 17>;
arch/riscv/boot/dts/allwinner/sunxi-d1s-t113.dtsi-  dmas = <&dma 18>, <&dma 18>;
arch/riscv/boot/dts/allwinner/sunxi-d1s-t113.dtsi-  dmas = <&dma 19>, <&dma 19>;

Switch dma-names order to tx->rx as the first step in fixing the
inconsistency. The remaining DTS fixes will be handled by separate
patches.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230321215624.78383-2-cristian.ciocaltea@collabora.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
index 8212a9f483b5..3862411c77b5 100644
--- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
+++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
@@ -72,8 +72,8 @@ properties:
 
   dma-names:
     items:
-      - const: rx
       - const: tx
+      - const: rx
 
   snps,uart-16550-compatible:
     description: reflects the value of UART_16550_COMPATIBLE configuration