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 uart0. Implement GPIO0_B5 as rts-gpios with RTS_ON_SEND
option enabled (default) so that driver mode gets enabled while sending
(RTS high) and receiver mode gets enabled while not sending (RTS low).
In full-duplex mode (em485 is disabled), DE is connected to GPIO0_B5 and
RE is grounded (enabled). Since GPIO0_B5 is implemented as rts-gpios, the
driver mode gets enabled whenever we want to send something and RE is not
affected (always enabled) in this case by the state of RTS.
Signed-off-by: Farouk Bouabid <farouk.bouabid@xxxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts b/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts
index 16798eb77077..ae398acdcf45 100644
--- a/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts
+++ b/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts
@@ -227,6 +227,7 @@ &uart0 {
&uart5 {
pinctrl-0 = <&uart5_xfer>;
+ rts-gpios = <&gpio0 RK_PB5 GPIO_ACTIVE_HIGH>;
status = "okay";
};
--
2.34.1
