[PATCH v4 6/6] arm64: dts: rockchip: px30-ringneck-haikou: add rs485 support on uart5

Farouk Bouabid
2024-01-26T14:59:48Z

A hardware switch can set the rs485 transceiver into half or full duplex
mode.

Switching to the half-duplex mode requires the user to enable em485 on
uart5 using ioctl, DE/RE are both connected to GPIO0_B5 which is the
RTS signal for uart5. Which means GPIO0_B5 is implemented as rs485
rx-enable gpio.

In full-duplex mode (em485 is disabled), DE is connected to GPIO0_B5 and
RE is grounded (active). This requires rx-enable gpio to be inactive to
enable DE as well.

Signed-off-by: Farouk Bouabid <farouk.bouabid@theobroma-systems.com>
---
arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts b/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts
index 16798eb77077..369a6518a487 100644
--- a/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts
+++ b/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts
@@ -227,6 +227,8 @@ &uart0 {

&uart5 {
pinctrl-0 = <&uart5_xfer>;
+ rs485-rx-enable-gpios = <&gpio0 RK_PB5 GPIO_ACTIVE_LOW>;
+ rs485-rx-enable-inactive-when-rs485-disabled;
status = "okay";
};