[PATCH 2/2] ARM: dts: renesas: r9a06g032: Drop snps,dw-apb-uart compatibility

[Geert Uytterhoeven]

make dtbs_check:

    arch/arm/boot/dts/renesas/r9a06g032-rzn1d400-db.dtb: serial at 40060000: compatible: 'oneOf' conditional failed, one must be fixed:
	    ['renesas,r9a06g032-uart', 'renesas,rzn1-uart', 'snps,dw-apb-uart'] is too long
    ...

As per commit 72b0505f0830df95 ("dt: serial: Add Renesas RZ/N1 binding
documentation"), the RZ/N1 UART is a modified Synopsys DesignWare UART.
The modifications only relate to DMA, so you could actually use the
controller with the Synopsys compatible string if you are not using DMA,
but you should not do so.  Hence the first three UARTs (which don't
support DMA) were added with a "snps,dw-apb-uart" fallback, to use the
existing Synopsys DesignWare UART support.

Since support for the RZ/N1-specific compatible value was added to the
driver a long time ago (commit 2ff5fa7f742ab0c6 ("serial: 8250_dw: Add
compatible string for Renesas RZ/N1 UART") in v4.19), the extra
compatible value can be dropped safely.

Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>
---
Alternatively, the bindings[1] could be augmented with an extra section:

    - items:
        - enum:
            - renesas,r9a06g032-uart
            - renesas,r9a06g033-uart
        - const: renesas,rzn1-uart
        - const: snps,dw-apb-uart     # RZ/N1 without DMA

and perhaps extra logic to prohibit the dmas property when both
renesas,rzn1-uart and snps,dw-apb-uart are present.

Given the complexity of the latter, I went for the simple solution.

[1] Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
---
 arch/arm/boot/dts/renesas/r9a06g032.dtsi | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm/boot/dts/renesas/r9a06g032.dtsi b/arch/arm/boot/dts/renesas/r9a06g032.dtsi
index 87e03446fb4de705..fc523106c2a4c6a0 100644
--- a/arch/arm/boot/dts/renesas/r9a06g032.dtsi
+++ b/arch/arm/boot/dts/renesas/r9a06g032.dtsi
@@ -171,7 +171,7 @@ usb at 2,0 {
 		};
 
 		uart0: serial at 40060000 {
-			compatible = "renesas,r9a06g032-uart", "renesas,rzn1-uart", "snps,dw-apb-uart";
+			compatible = "renesas,r9a06g032-uart", "renesas,rzn1-uart";
 			reg = <0x40060000 0x400>;
 			interrupts = <GIC_SPI 6 IRQ_TYPE_LEVEL_HIGH>;
 			reg-shift = <2>;
@@ -182,7 +182,7 @@ uart0: serial at 40060000 {
 		};
 
 		uart1: serial at 40061000 {
-			compatible = "renesas,r9a06g032-uart", "renesas,rzn1-uart", "snps,dw-apb-uart";
+			compatible = "renesas,r9a06g032-uart", "renesas,rzn1-uart";
 			reg = <0x40061000 0x400>;
 			interrupts = <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>;
 			reg-shift = <2>;
@@ -193,7 +193,7 @@ uart1: serial at 40061000 {
 		};
 
 		uart2: serial at 40062000 {
-			compatible = "renesas,r9a06g032-uart", "renesas,rzn1-uart", "snps,dw-apb-uart";
+			compatible = "renesas,r9a06g032-uart", "renesas,rzn1-uart";
 			reg = <0x40062000 0x400>;
 			interrupts = <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>;
 			reg-shift = <2>;
-- 
2.43.0