Input: Mac button emulation - allow compiling as a module

Not all systems require Mac-style button emulation, however distributions
enable it by default so it is readily available. Allow compiling it as a
module so it can be loaded only on systems that actually require it.
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/macintosh/Kconfig

@@ -171,9 +171,8 @@ config INPUT_ADBHID
 	  If unsure, say Y.
 
 config MAC_EMUMOUSEBTN
-	bool "Support for mouse button 2+3 emulation"
-	depends on SYSCTL
-	select INPUT
+	tristate "Support for mouse button 2+3 emulation"
+	depends on SYSCTL && INPUT
 	help
 	  This provides generic support for emulating the 2nd and 3rd mouse
 	  button with keypresses.  If you say Y here, the emulation is still
@@ -185,6 +184,9 @@ config MAC_EMUMOUSEBTN
 
 	  If you have an Apple machine with a 1-button mouse, say Y here.
 
+	  To compile this driver as a module, choose M here: the
+	  module will be called mac_hid.
+
 config THERM_WINDTUNNEL
 	tristate "Support for thermal management on Windtunnel G4s"
 	depends on I2C && I2C_POWERMAC && PPC_PMAC && !PPC_PMAC64

drivers/macintosh/mac_hid.c

@@ -14,6 +14,8 @@
 #include <linux/input.h>
 #include <linux/module.h>
 
+MODULE_LICENSE("GPL");
+
 static int mouse_emulate_buttons;
 static int mouse_button2_keycode = KEY_RIGHTCTRL;	/* right control key */
 static int mouse_button3_keycode = KEY_RIGHTALT;	/* right option key */
@@ -252,7 +254,6 @@ static ctl_table mac_hid_root_dir[] = {
 
 static struct ctl_table_header *mac_hid_sysctl_header;
 
-
 static int __init mac_hid_init(void)
 {
 	mac_hid_sysctl_header = register_sysctl_table(mac_hid_root_dir);
@@ -261,5 +262,13 @@ static int __init mac_hid_init(void)
 
 	return 0;
 }
+module_init(mac_hid_init);
 
-device_initcall(mac_hid_init);
+static void __exit mac_hid_exit(void)
+{
+	unregister_sysctl_table(mac_hid_sysctl_header);
+
+	if (mouse_emulate_buttons)
+		mac_hid_stop_emulation();
+}
+module_exit(mac_hid_exit);