Add optional DKMS target to Makefile (v2)

Using DKMS, the driver will be automatically rebuilt when
the kernel is updated.

* `make dkms` to install via DKMS
* `make dkms_clean` to remove from DKMS

Signed-off-by: Burt P <pburt0@gmail.com>

Makefile

@@ -20,6 +20,19 @@ endif
 SYSTEM_MAP	:= /boot/System.map-$(TARGET)
 
 DRIVER := it87
+ifneq ("","$(wildcard .git/*)")
+DRIVER_VERSION := $(shell git describe --long)
+else
+ifneq ("", "$(wildcard VERSION)")
+DRIVER_VERSION := $(shell cat VERSION)
+else
+DRIVER_VERSION := unknown
+endif
+endif
+
+# DKMS
+DKMS_ROOT_PATH=/usr/src/$(DRIVER)-$(DRIVER_VERSION)
+MODPROBE_OUTPUT=$(shell lsmod | grep it87)
 
 # Directory below /lib/modules/$(TARGET)/kernel into which to install
 # the module:
@@ -38,17 +51,13 @@ ifneq ("","$(wildcard $(MODDESTDIR)/*.ko.xz)")
 COMPRESS_XZ := y
 endif
 
-.PHONY: all install modules modules_install clean
+.PHONY: all install modules modules_install clean dkms dkms_clean
 
 all: modules
 
 # Targets for running make directly in the external module directory:
 
-ifneq ("","$(wildcard .git/*)")
-IT87_CFLAGS=-DIT87_DRIVER_VERSION='\"$(shell git describe --long)\"'
-else
-IT87_CFLAGS=-DIT87_DRIVER_VERSION='\"<unknown>\"'
-endif
+IT87_CFLAGS=-DIT87_DRIVER_VERSION='\"$(DRIVER_VERSION)\"'
 
 modules:
 	@$(MAKE) EXTRA_CFLAGS="$(IT87_CFLAGS)" -C $(KERNEL_BUILD) M=$(CURDIR) $@
@@ -68,3 +77,24 @@ ifeq ($(COMPRESS_XZ), y)
 	@xz -f $(MODDESTDIR)/$(DRIVER).ko
 endif
 	depmod -a -F $(SYSTEM_MAP) $(TARGET)
+
+dkms:
+	@sed -i -e '/^PACKAGE_VERSION=/ s/=.*/=\"$(DRIVER_VERSION)\"/' dkms.conf
+	@echo "$(DRIVER_VERSION)" >VERSION
+	@mkdir $(DKMS_ROOT_PATH)
+	@cp `pwd`/dkms.conf $(DKMS_ROOT_PATH)
+	@cp `pwd`/VERSION $(DKMS_ROOT_PATH)
+	@cp `pwd`/Makefile $(DKMS_ROOT_PATH)
+	@cp `pwd`/compat.h $(DKMS_ROOT_PATH)
+	@cp `pwd`/it87.c $(DKMS_ROOT_PATH)
+	@dkms add -m $(DRIVER) -v $(DRIVER_VERSION)
+	@dkms build -m $(DRIVER) -v $(DRIVER_VERSION)
+	@dkms install --force -m $(DRIVER) -v $(DRIVER_VERSION)
+	@modprobe $(DRIVER)
+
+dkms_clean:
+	@if [ ! -z "$(MODPROBE_OUTPUT)" ]; then \
+		rmmod $(DRIVER);\
+	fi
+	@dkms remove -m $(DRIVER) -v $(DRIVER_VERSION) --all
+	@rm -rf $(DKMS_ROOT_PATH)

dkms.conf

@@ -0,0 +1,7 @@
+MAKE="make"
+CLEAN="make clean"
+PACKAGE_NAME="it87"
+PACKAGE_VERSION="to be filled by make dkms"
+BUILT_MODULE_NAME[0]="it87"
+DEST_MODULE_LOCATION[0]="/kernel/drivers/hwmon/it87"
+AUTOINSTALL="yes"

it87.c

@@ -4263,6 +4263,7 @@ module_param(fix_pwm_polarity, bool, 0000);
 MODULE_PARM_DESC(fix_pwm_polarity,
 		 "Force PWM polarity to active high (DANGEROUS)");
 MODULE_LICENSE("GPL");
+MODULE_VERSION(IT87_DRIVER_VERSION);
 
 module_init(sm_it87_init);
 module_exit(sm_it87_exit);