[IMX8MM][MYON2] auto apply of board rev overlay

The commit introduces a new routine for loading and applying the overlay
of the device tree, depending on the detected revision of the board.
This routine is stored in the "fdt_overlay_board_rev" env variable.

In order to execute this code after the loading of the dtb, we overwrite
the command "fdt_overlay_load2ram" (MACRO_ENV_FDT_LOAD_OVERLAY_BASE).

board/seco/imx8mm_myon2/README

@@ -65,15 +65,5 @@ Device tree overlays
 There are few version/revision of Myon II i.MX8MM modules. They may have different hardware components (e.g. audio codecs),
 and to enable these components in Linux, there are device tree overlays.
 
-The DT overlay can be set with the "seco_config" command in U-Boot, for example:
-
-MX SECO U-Boot > seco_config
-…
- __________________________________________________
-     Choose FDT overlay option for board revision.
- __________________________________________________
-1) not use
-2) V1R4
-3) V2R1
-> 2
-…
+The DT overlay will be applied automatically if the board revision is detected and device tree overlay for that revision
+exists on the boot partition.

board/seco/imx8mm_myon2/env_conf.h

@@ -114,14 +114,6 @@ video_mode_t video_mode_list_novideo [] = {
 #ifdef CONFIG_OF_LIBFDT_OVERLAY
 /* *********************************** FDT OVERLAY *********************************** */
 overlay_list_t overlay_peripheral_list[] = {
-	{
-		.title = "board revision",
-		.options = {
-			{ "not use", "" },		// default
-			{ "V1R4", STR(ENV_DTBO_MYON2_IMX8MM_V1R4) },
-			{ "V2R1", STR(ENV_DTBO_MYON2_IMX8MM_V2R1) },
-		},
-	},
 	{
 		.title = "display",
 		.options = {

include/configs/seco_imx8mm_myon2.h

@@ -325,6 +325,35 @@
 
 #define ENV_BOOT_TYPE				booti
 
+#ifdef CONFIG_OF_LIBFDT_OVERLAY
+#define ENV_DEVICE_CONFIG \
+	"fdt_overlay_board_rev= echo \"Applying board revision specific overlay...\"; " \
+	    "if itest.s ${board_rev} == \"????\"; then echo \"Unknown revision of the board\"; exit; fi; " \
+	    "if test -n ${board_rev}; then " \
+	        "if load mmc \"${fdt_device_id}:${fdt_partition}\" 0x45000000 seco-imx8mm-myon2-${board_rev}.dtbo; then " \
+	            "fdt apply 0x45000000; " \
+	        "fi; " \
+	    "fi;\0" \
+
+#endif
+
 #include "seco_mx8_env.h"
 
+#ifdef CONFIG_OF_LIBFDT_OVERLAY
+#undef MACRO_ENV_FDT_LOAD_OVERLAY_BASE
+/* Here we overwrite the fdt_overlay_load2ram command, to additionally apply
+   device tree overlay for detected board revision.
+*/
+
+#define MACRO_ENV_FDT_LOAD_OVERLAY_BASE \
+	fdt addr ${fdt_loadaddr}; fdt resize ${fdt_resize}; \
+	if test -n "${fdt_overlay_carrier_file}"; then run fdt_overlay_carrier_cmd; fi; \
+	seco_config fdtoverlay ; \
+	if test -n "${fdt_overlay_per_cmd}"; then run fdt_overlay_per_cmd; fi; \
+	if test -n "${fdt_overlay_video_cmd}"; then run fdt_overlay_video_cmd; fi; \
+	if test -n "${fdt_overlay_touch_cmd}"; then run fdt_overlay_touch_cmd; fi; \
+	if test -n "${fdt_overlay_board_rev}"; then run fdt_overlay_board_rev; fi; \
+
+#endif
+
 #endif /* __SECO_IMX8MM_MYON2_H */

include/configs/seco_mx8_dtbo.h

@@ -69,6 +69,4 @@
 #define ENV_DTBO_C57_EDP                seco-imx8qxp-c57-sn65dsi86-edp.dtbo
 
 #define ENV_DTBO_ATM0700L61             seco-imx8mm-myon2-atm0700l61ct.dtbo
-#define ENV_DTBO_MYON2_IMX8MM_V1R4      seco-imx8mm-myon2-v1r4.dtbo
-#define ENV_DTBO_MYON2_IMX8MM_V2R1      seco-imx8mm-myon2-v2r1.dtbo
 #endif   /* __SECO_MX8_DTBO_H  */