HID: wiimote: add sub-device module infrastructure

To avoid loading all sub-device drivers for every Wii Remote, even though
the required hardware might not be available, we introduce a module layer.

The module layer specifies which sub-devices are available on each
device-type. After device detection, we only load the modules for the
detected device. If module loading fails, we unload everything and mark
the device as WIIMOTE_DEV_UNKNOWN. As long as a device is marked as
"unknown", no sub-devices will be used and the device is considered
unsupported.

All the different sub-devices, including KEYS, RUMBLE, BATTERY, LEDS,
ACCELEROMETER, IR and more will be ported in follow-up patches to the new
module layer.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-wiimote.h b/drivers/hid/hid-wiimote.h
index 3441702..3c94e3c 100644
--- a/drivers/hid/hid-wiimote.h
+++ b/drivers/hid/hid-wiimote.h
@@ -108,6 +108,33 @@
 	struct work_struct init_worker;
 };
 
+/* wiimote modules */
+
+enum wiimod_module {
+	WIIMOD_NUM,
+	WIIMOD_NULL = WIIMOD_NUM,
+};
+
+#define WIIMOD_FLAG_INPUT		0x0001
+
+struct wiimod_ops {
+	__u16 flags;
+	unsigned long arg;
+	int (*probe) (const struct wiimod_ops *ops,
+		      struct wiimote_data *wdata);
+	void (*remove) (const struct wiimod_ops *ops,
+			struct wiimote_data *wdata);
+
+	void (*in_keys) (struct wiimote_data *wdata, const __u8 *keys);
+	void (*in_accel) (struct wiimote_data *wdata, const __u8 *accel);
+	void (*in_ir) (struct wiimote_data *wdata, const __u8 *ir, bool packed,
+		       unsigned int id);
+};
+
+extern const struct wiimod_ops *wiimod_table[WIIMOD_NUM];
+
+/* wiimote requests */
+
 enum wiiproto_reqs {
 	WIIPROTO_REQ_NULL = 0x0,
 	WIIPROTO_REQ_RUMBLE = 0x10,