Handle manual build with Makefile

Makefile

@@ -2,10 +2,44 @@ obj-m += sharp.o
 sharp-objs += src/main.o src/drm_iface.o src/params_iface.o src/ioctl_iface.o
 ccflags-y := -DDEBUG -g -std=gnu99 -Wno-declaration-after-statement
 
-.PHONY: all clean
+.PHONY: all clean install uninstall
 
-all:
+# LINUX_DIR is set by Buildroot, but not if running manually
-	$(MAKE) -C '$(LINUX_DIR)' M='$(PWD)' modules
+ifeq ($(LINUX_DIR),)
+LINUX_DIR := /lib/modules/$(shell uname -r)/build
+endif
+
+BOOT_CONFIG_LINE := dtoverlay=sharp
+
+all: sharp.ko sharp.dtbo
+
+sharp.ko: src/*.c src/*.h
+	$(MAKE) -C '$(LINUX_DIR)' M='$(shell pwd)' modules
+
+sharp.dtbo: sharp.dts
+	dtc -@ -I dts -O dtb -W no-unit_address_vs_reg -o $@ $<
+
+install: sharp.ko sharp.dtbo
+	# Install kernel module
+	$(MAKE) -C '$(LINUX_DIR)' M='$(shell pwd)' modules_install
+	# Install device tree overlay
+	install -D -m 0644 sharp.dtbo /boot/overlays/
+	# Add configuration line if it wasn't already there
+	grep -qxF '$(BOOT_CONFIG_LINE)' /boot/config.txt \
+		|| echo '$(BOOT_CONFIG_LINE)' >> /boot/config.txt
+	# Add auto-load module line if it wasn't already there
+	grep -qxF 'sharp' /etc/modules \
+		|| echo 'sharp' >> /etc/modules
+	# Rebuild dependencies
+	depmod -A
+
+uninstall:
+	# Remove auto-load module line and create a backup file
+	sed -i.save '/sharp/d' /etc/modules
+	# Remove configuration line and create a backup file
+	sed -i.save '/$(BOOT_CONFIG_LINE)/d' /boot/config.txt
+	# Remove device tree overlay
+	rm -f /boot/overlays/sharp.dtbo
 
 clean:
-	$(MAKE) -C '$(LINUX_DIR)' M='$(PWD)' clean
+	$(MAKE) -C '$(LINUX_DIR)' M='$(shell pwd)' clean