[Raspberry Pi4] doesn't load device tree overlay

[nguyenanhgiau]

Hi @rsglobal I'm trying to add 3 buttons for rpi4 (power, vol- and vol+). Firstly, I create a device tree overlay in kernel: arch/arm/boot/dts/overlays/arpi-gpio-key-overlay.dts

@@ -0,0 +1,36 @@
/dts-v1/;
/plugin/;
/ {
    compatible = "brcm,bcm2835", "brcm,bcm2708", "brcm,bcm2709";

    fragment@0 {
        target-path = "/";
        __overlay__ {
            keypad: arpi_keys {
                compatible = "gpio-keys";
                #address-cells = <1>;
                #size-cells = <0>;
                gpio-key,wakeup;
                autorepeat;

                button@pow {
                    label = "POWER";
                    linux,code = <116>;
                    gpios = <&gpio 21 1>;
                };

                button@vlu {
                    label = "VOLUME_UP";
                    linux,code = <115>;
                    gpios = <&gpio 20 1>;
                };

                button@vld {
                    label = "VOLUME_DOWN";
                    linux,code = <114>;
                    gpios = <&gpio 16 1>;
                };
            };
        };
    };
}; 

Then, I add this dtoverlay into arch/arm/boot/dts/overlays/Makefile

@@ -29,6 +29,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
    audioinjector-wm8731-audio.dtbo \
    audiosense-pi.dtbo \
    audremap.dtbo \
    arpi-gpio-key.dtbo \
    balena-fin.dtbo \
    cma.dtbo \
    dht11.dtbo \

To load this overlay, I add the following line in config.txt

dtoverlay=dwc2
dtoverlay=vc4-kms-v3d-pi4

# Adding gpio-key
gpio=16,20,21=ip,pu
dtoverlay=arpi-gpio-key

Finally, I build with command: "make images -j$(nproc)" I'm sure this overlay was built because there is arpi-gpio-key.dtbo file in output. But not sure It was copied to boot image.

When the device boot to home screen. I didn't see my buttons in /sys/class/input I make sure this overlay worked well on raspbian OS.

I'm curious why dwc2 was loaded, but arpi-gpio-key was not. Anything missing? Thanks a lot!

[rsglobal]

Hi, you also have to ship compiled dts (.dtb) file. e.g.: https://github.com/GloDroid/glodroid_device/blob/cb5423bf00057a788790442569bcfaef5819a1d0/platform/uboot/uboot.mk#L184

[rsglobal]

Something like this:

ifeq ($(PRODUCT_BOARD_PLATFORM),broadcom)
BOOT_FILES := \
    $(RPI_FIRMWARE_DIR)/boot/bootcode.bin \
    $(RPI_FIRMWARE_DIR)/boot/start_x.elf \
    $(RPI_FIRMWARE_DIR)/boot/start4x.elf \
    $(RPI_FIRMWARE_DIR)/boot/fixup_x.dat \
    $(RPI_FIRMWARE_DIR)/boot/fixup4x.dat \
    $(PRODUCT_OUT)/obj/KERNEL_OBJ/arch/$(TARGET_ARCH)/boot/dts/broadcom/bcm2711-rpi-4-b.dtb \
    $(PRODUCT_OUT)/obj/KERNEL_OBJ/arch/$(TARGET_ARCH)/boot/dts/broadcom/bcm2711-rpi-400.dtb \
    $(PRODUCT_OUT)/obj/KERNEL_OBJ/arch/$(TARGET_ARCH)/boot/dts/broadcom/bcm2711-rpi-cm4.dtb \

+CUSTOM_RPI_OVERLAY_FILES := $(PRODUCT_OUT)/obj/KERNEL_OBJ/arch/$(TARGET_ARCH)/boot/dts/broadcom/overlays/arpi-gpio-key-overlay.dtb

OVERLAY_FILES := $(sort $(shell find -L $(RPI_FIRMWARE_DIR)/boot/overlays))

$(PRODUCT_OUT)/bootloader-sd.img: $(UBOOT_BINARY) $(OVERLAY_FILES) $(ATF_BINARY) $(RPI_CONFIG) $(KERNEL_BINARY)
    dd if=/dev/null of=$@ bs=1 count=1 seek=$$(( 128 * 1024 * 1024 - 256 * 512 ))
    /sbin/mkfs.vfat -F 32 -n boot $@
    /usr/bin/mcopy -i $@ $(UBOOT_BINARY) ::$(notdir $(UBOOT_BINARY))
    /usr/bin/mcopy -i $@ $(ATF_BINARY) ::$(notdir $(ATF_BINARY))
    /usr/bin/mcopy -i $@ $(RPI_CONFIG) ::$(notdir $(RPI_CONFIG))
    /usr/bin/mcopy -i $@ $(BOOT_FILES) ::
    /usr/bin/mmd -i $@ ::overlays
    /usr/bin/mcopy -i $@ $(OVERLAY_FILES) ::overlays/
+   /usr/bin/mcopy -i $@ $(CUSTOM_RPI_OVERLAY_FILES) ::overlays/
endif

[nguyenanhgiau]

Hi @rsglobal It worked well. Thank you for your suggestion This is my patch:

--- a/platform/uboot/uboot.mk
+++ b/platform/uboot/uboot.mk
@@ -183,6 +183,11 @@ BOOT_FILES := \
     $(RPI_FIRMWARE_DIR)/boot/bcm2710-rpi-3-b-plus.dtb \
     $(PRODUCT_OUT)/obj/KERNEL_OBJ/arch/$(TARGET_ARCH)/boot/dts/$(KERNEL_DTB_FILE) \

+CUSTOM_RPI_OVERLAY_DIR := $(PRODUCT_OUT)/obj/KERNEL_OBJ/arch/$(TARGET_ARCH)/boot/dts/overlays
+
+CUSTOM_RPI_OVERLAY_FILES := \
+       $(CUSTOM_RPI_OVERLAY_DIR)/arpi-gpio-key.dtbo
+
 OVERLAY_FILES := $(sort $(shell find -L $(RPI_FIRMWARE_DIR)/boot/overlays))

 $(PRODUCT_OUT)/bootloader-sd.img: $(UBOOT_BINARY) $(OVERLAY_FILES) $(ATF_BINARY) $(RPI_CONFIG) $(KERNEL_BINARY)
@@ -194,6 +199,7 @@ $(PRODUCT_OUT)/bootloader-sd.img: $(UBOOT_BINARY) $(OVERLAY_FILES) $(ATF_BINARY)
        /usr/bin/mcopy -i $@ $(BOOT_FILES) ::
        /usr/bin/mmd -i $@ ::overlays
        /usr/bin/mcopy -i $@ $(OVERLAY_FILES) ::overlays/
+       /usr/bin/mcopy -i $@ $(CUSTOM_RPI_OVERLAY_FILES) ::overlays/
 endif