arm64: dts: phygate-tauri-l: add overlays for RS232 and RS485

UART2 and UART4 can used in following combination,

2 x RS232:
- UART2 and UART4 without flow control
- MUX selection GPIO3_20 must be held low

1 x RS232 + 1 x RS485:
- UART2 - RS232
- UART4 - RS485
- MUX selection GPIO3_20 must be held high
- RE/DE for RS485 controlled with GPIO3_25

1 x RS232 with flow control:
- UART2 - RS232
- MUX selection GPIO3_20 must be held low

Signed-off-by: Parthiban Nallathambi <parthiban@linumiz.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

1 files changed, 76 insertions, 0 deletions

diff --git a/arch/arm64/boot/dts/freescale/imx8mm-phygate-tauri-l-rs232-rs485.dtso b/arch/arm64/boot/dts/freescale/imx8mm-phygate-tauri-l-rs232-rs485.dtso
new file mode 100644
index 000000000000..f4448cde0407
--- /dev/null
+++ b/arch/arm64/boot/dts/freescale/imx8mm-phygate-tauri-l-rs232-rs485.dtso
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright (C) 2021 PHYTEC Messtechnik GmbH
+ * Author: Jens Lang <j.lang@phytec.de>
+ *
+ * Tauri-L RS232 + RS485:
+ *  - GPIO3_20 uart4_rs485_en needs to be driven high (active)
+ *  - GPIO3_25 RS485_DE Driver enable
+ */
+
+#include <dt-bindings/clock/imx8mm-clock.h>
+#include <dt-bindings/gpio/gpio.h>
+#include "imx8mm-pinfunc.h"
+
+/dts-v1/;
+/plugin/;
+
+&{/} {
+	compatible = "phytec,imx8mm-phygate-tauri-l";
+
+};
+
+&gpio3 {
+	pinctrl-names = "default";
+	pinctrcl-0 = <&pinctrl_gpio3_hog>;
+
+	uart4_rs485_en {
+		gpio-hog;
+		gpios = <20 GPIO_ACTIVE_HIGH>;
+		output-high;
+		line-name = "uart4_rs485_en";
+	};
+};
+
+/* UART2 - RS232  */
+&uart2 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_uart2>;
+	assigned-clocks = <&clk IMX8MM_CLK_UART2>;
+	assigned-clock-parents = <&clk IMX8MM_SYS_PLL1_80M>;
+	status = "okay";
+};
+
+/* UART4 - RS485  */
+&uart4 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_uart4>;
+	assigned-clocks = <&clk IMX8MM_CLK_UART4>;
+	assigned-clock-parents = <&clk IMX8MM_SYS_PLL1_80M>;
+	rts-gpios = <&gpio3 25 GPIO_ACTIVE_HIGH>;
+	linux,rs485-enabled-at-boot-time;
+	status = "okay";
+};
+
+&iomuxc {
+	pinctrl_gpio3_hog: gpio3hoggrp {
+		fsl,pins = <
+			MX8MM_IOMUXC_SAI5_RXC_GPIO3_IO20	0x49
+		>;
+	};
+
+	pinctrl_uart2: uart2grp {
+		fsl,pins = <
+			MX8MM_IOMUXC_UART2_RXD_UART2_DCE_RX	0x00
+			MX8MM_IOMUXC_UART2_TXD_UART2_DCE_TX	0x00
+		>;
+	};
+
+	pinctrl_uart4: uart4grp {
+		fsl,pins = <
+			MX8MM_IOMUXC_UART4_RXD_UART4_DCE_RX	0x49
+			MX8MM_IOMUXC_UART4_TXD_UART4_DCE_TX	0x49
+			MX8MM_IOMUXC_SAI5_MCLK_GPIO3_IO25	0x49
+		>;
+	};
+};