From 539e87dd661f5ce321019c27ab15cad55345e429 Mon Sep 17 00:00:00 2001 From: Felix Brack Date: Thu, 29 May 2025 15:53:24 +0200 Subject: [PATCH] ARM: dts: am335x-pdu001: Fix RS-485 transceiver switching The wiring of the RS-485 transceiver of UART0 of the PDU-001 board allows sending or receiving date exclusively. In other words: no character transmitted will ever be received. Hence the tx-filter counter in the OMAP serial driver can't work correctly as it relies on receiving the transmitted characters. This in turn will prevent reception of data unless we disable the tx-filter counter. This patch disables the tx-filter counter by enabling the DTS setting rs485-rx-during-tx. This might sound like the opposite to be done but it uses the enabling of rs485-rx-during-tx not for receiving the data transmitted but for disabling the tx-fiter counter. Tested-by: Felix Brack Signed-off-by: Felix Brack Link: https://lore.kernel.org/r/20250529135324.182868-1-fb@ltec.ch Signed-off-by: Kevin Hilman --- arch/arm/boot/dts/ti/omap/am335x-pdu001.dts | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm/boot/dts/ti/omap/am335x-pdu001.dts b/arch/arm/boot/dts/ti/omap/am335x-pdu001.dts index f0da94a738d58..c9ccb9de21ad7 100644 --- a/arch/arm/boot/dts/ti/omap/am335x-pdu001.dts +++ b/arch/arm/boot/dts/ti/omap/am335x-pdu001.dts @@ -258,6 +258,7 @@ rts-gpios = <&gpio1 9 GPIO_ACTIVE_HIGH>; rs485-rts-active-high; + rs485-rx-during-tx; rs485-rts-delay = <0 0>; linux,rs485-enabled-at-boot-time; -- 2.47.2