1// SPDX-License-Identifier: (GPL-2.0+ OR MIT) 2/* 3 * Copyright 2022 Gateworks Corporation 4 * 5 * GW72xx RS422 (RS485 full duplex): 6 * - GPIO1_0 rs485_term selects on-chip termination 7 * - GPIO4_0 rs485_en needs to be driven high (active) 8 * - GPIO4_2 rs485_hd needs to be driven low (in-active) 9 * - UART4_TX is DE for RS485 transmitter 10 * - RS485_EN needs to be pulled high 11 * - RS485_HALF needs to be low 12 */ 13 14#include <dt-bindings/gpio/gpio.h> 15 16#include "imx8mm-pinfunc.h" 17 18/dts-v1/; 19/plugin/; 20 21&gpio4 { 22 rs485-en-hog { 23 gpio-hog; 24 gpios = <0 GPIO_ACTIVE_HIGH>; 25 output-high; 26 line-name = "rs485_en"; 27 }; 28 29 rs485-hd-hog { 30 gpio-hog; 31 gpios = <2 GPIO_ACTIVE_HIGH>; 32 output-low; 33 line-name = "rs485_hd"; 34 }; 35}; 36 37&uart2 { 38 pinctrl-names = "default"; 39 pinctrl-0 = <&pinctrl_uart2>; 40 rts-gpios = <&gpio5 29 GPIO_ACTIVE_HIGH>; 41 linux,rs485-enabled-at-boot-time; 42 status = "okay"; 43}; 44 45&uart4 { 46 status = "disabled"; 47}; 48 49&iomuxc { 50 pinctrl_uart2: uart2grp { 51 fsl,pins = < 52 MX8MM_IOMUXC_UART2_RXD_UART2_DCE_RX 0x140 53 MX8MM_IOMUXC_UART2_TXD_UART2_DCE_TX 0x140 54 MX8MM_IOMUXC_UART4_TXD_GPIO5_IO29 0x140 55 >; 56 }; 57}; 58