[C61] add port1, port2 rs485 support

* enabled at u-boot: seco_config tool

arch/arm64/boot/dts/seco/overlays/Makefile

@@ -26,8 +26,10 @@ dtbo-$(CONFIG_ARCH_MXC) += \
 	seco-imx8qm-c43-lvds-sn65dsi86.dtbo\
 	seco-imx8mm-c61-port1-gpios.dtbo\
 	seco-imx8mm-c61-port1-rs232.dtbo\
+	seco-imx8mm-c61-port1-rs485.dtbo\
 	seco-imx8mm-c61-port2-gpios.dtbo\
 	seco-imx8mm-c61-port2-rs232.dtbo\
+	seco-imx8mm-c61-port2-rs485.dtbo\
 	seco-imx8mp-d18-hdmi.dtbo\
 	seco-imx8mp-d18-edp.dtbo\
 	seco-imx8mp-d18-lvds-fhd.dtbo\

arch/arm64/boot/dts/seco/overlays/seco-imx8mm-c61-port1-rs485-overlay.dts

+/*
+ * Copyright 2017 NXP
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "fsl,imx8mm-evk", "seco,imx8mm-c61", "fsl,imx8mm";
+
+/*  __________________________________________________________________________
+ * |                                                                          |
+ * |                               RS485 PORT1                                |
+ * |__________________________________________________________________________|
+ */
+
+	fragment@uart3 {
+		target = <&uart3>;
+		__overlay__ {
+			status = "okay";
+			linux,rs485-enabled-at-boot-time;
+			rs485-rx-during-tx;
+		};
+	};
+
+};
+

arch/arm64/boot/dts/seco/overlays/seco-imx8mm-c61-port2-rs485-overlay.dts

+/*
+ * Copyright 2017 NXP
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "fsl,imx8mm-evk", "seco,imx8mm-c61", "fsl,imx8mm";
+
+/*  __________________________________________________________________________
+ * |                                                                          |
+ * |                               RS485 PORT2                                |
+ * |__________________________________________________________________________|
+ */
+
+	fragment@uart4 {
+		target = <&uart4>;
+		__overlay__ {
+			status = "okay";
+			linux,rs485-enabled-at-boot-time;
+			rs485-rx-during-tx;
+		};
+	};
+
+};
+