Add separated dtb for U-Boot with fastboot

Signed-off-by: Mikhail Vanyulin <mikhail.vanyulin@rtsoft.de>

arch/arm/dts/Makefile

@@ -906,7 +906,8 @@ dtb-$(CONFIG_ARCH_IMX8M) += \
 	seco-imx8mq-c20.dtb \
 	seco-imx8mq-c12.dtb \
 	seco-imx8mm-c61.dtb \
-	seco-imx8mm-myon2.dtb
+	seco-imx8mm-myon2.dtb \
+	seco-imx8mm-myon2-otg.dtb
 
 dtb-$(CONFIG_ARCH_IMXRT) += imxrt1050-evk.dtb \
 	imxrt1020-evk.dtb

arch/arm/dts/seco-imx8mm-myon2-otg.dts

+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright 2018 NXP
+ * Copyright 2024 SECO
+ */
+
+/dts-v1/;
+
+#include "seco-imx8mm-myon2.dts"
+
+&usbotg1 {
+	dr_mode = "otg";
+};

board/seco/imx8mm_myon2/README

@@ -44,11 +44,7 @@ Universal Serial Bus
 By default, the U-Boot configuration is built with a working USB hub and Ethernet on the ConXM carrier.
 Alternatively, the U-Boot image can be built with USB in "device" mode and fastboot enabled.
 
-1) Switch "dr_mode" to "otg" for "usbotg1" node in arch/arm/dts/seco-imx8mm-myon2.dts
-
-  sed -i '/pinctrl_otg1_pwrenable/{n;s/\tdr_mode =.*/\tdr_mode = "otg";/}' arch/arm/dts/seco-imx8mm-myon2.dts
-
-2) Build U-boot using alternative defconfig
+1) Build U-boot using alternative defconfig
 
   make seco_imx8mm_myon2_fastboot_defconfig
   make -j $(nproc) flash.bin

configs/seco_imx8mm_myon2_fastboot_defconfig

@@ -22,7 +22,7 @@ CONFIG_SPL_MMC_SUPPORT=y
 CONFIG_SPL_SERIAL_SUPPORT=y
 CONFIG_SPL_DRIVERS_MISC_SUPPORT=y
 CONFIG_SPL=y
-CONFIG_DEFAULT_DEVICE_TREE="seco-imx8mm-myon2"
+CONFIG_DEFAULT_DEVICE_TREE="seco-imx8mm-myon2-otg"
 CONFIG_FIT=y
 CONFIG_FIT_EXTERNAL_OFFSET=0x3000
 CONFIG_SPL_LOAD_FIT=y