HID: hid-lg4ff: Introduce a module parameter to disable automatic switch of compatibility mode

Introduce a module parameter to disable automatic switch of Logitech gaming
wheels from compatibility to native mode. This only applies to multimode wheels.
Signed-off-by: Michal Malý <madcatxster@devoid-pointer.net>
Tested-by: Simon Wood <simon@mungewell.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-lg.c

@@ -27,6 +27,7 @@
 #include "usbhid/usbhid.h"
 #include "hid-ids.h"
 #include "hid-lg.h"
+#include "hid-lg4ff.h"
 
 #define LG_RDESC		0x001
 #define LG_BAD_RELATIVE_KEYS	0x002
@@ -818,4 +819,10 @@ static struct hid_driver lg_driver = {
 };
 module_hid_driver(lg_driver);
 
+#ifdef CONFIG_LOGIWHEELS_FF
+int lg4ff_no_autoswitch = 0;
+module_param_named(lg4ff_no_autoswitch, lg4ff_no_autoswitch, int, S_IRUGO);
+MODULE_PARM_DESC(lg4ff_no_autoswitch, "Do not switch multimode wheels to their native mode automatically");
+#endif
+
 MODULE_LICENSE("GPL");

drivers/hid/hid-lg.h

@@ -24,16 +24,4 @@ int lg3ff_init(struct hid_device *hdev);
 static inline int lg3ff_init(struct hid_device *hdev) { return -1; }
 #endif
 
-#ifdef CONFIG_LOGIWHEELS_FF
-int lg4ff_adjust_input_event(struct hid_device *hid, struct hid_field *field,
-			     struct hid_usage *usage, __s32 value, struct lg_drv_data *drv_data);
-int lg4ff_init(struct hid_device *hdev);
-int lg4ff_deinit(struct hid_device *hdev);
-#else
-static inline int lg4ff_adjust_input_event(struct hid_device *hid, struct hid_field *field,
-					   struct hid_usage *usage, __s32 value, struct lg_drv_data *drv_data) { return 0; }
-static inline int lg4ff_init(struct hid_device *hdev) { return -1; }
-static inline int lg4ff_deinit(struct hid_device *hdev) { return -1; }
-#endif
-
 #endif

drivers/hid/hid-lg4ff.c

@@ -30,6 +30,7 @@
 
 #include "usbhid/usbhid.h"
 #include "hid-lg.h"
+#include "hid-lg4ff.h"
 #include "hid-ids.h"
 
 #define to_hid_device(pdev) container_of(pdev, struct hid_device, dev)
@@ -803,7 +804,8 @@ static int lg4ff_handle_multimode_wheel(struct hid_device *hid, u16 *real_produc
 	/* Switch from "Driving Force" mode to native mode automatically.
 	 * Otherwise keep the wheel in its current mode */
 	if (reported_product_id == USB_DEVICE_ID_LOGITECH_WHEEL &&
-	    reported_product_id != *real_product_id) {
+	    reported_product_id != *real_product_id &&
+	    !lg4ff_no_autoswitch) {
 		const struct lg4ff_compat_mode_switch *s;
 
 		switch (*real_product_id) {

drivers/hid/hid-lg4ff.h

+#ifndef __HID_LG4FF_H
+#define __HID_LG4FF_H
+
+#ifdef CONFIG_LOGIWHEELS_FF
+extern int lg4ff_no_autoswitch; /* From hid-lg.c */
+
+int lg4ff_adjust_input_event(struct hid_device *hid, struct hid_field *field,
+			     struct hid_usage *usage, __s32 value, struct lg_drv_data *drv_data);
+int lg4ff_init(struct hid_device *hdev);
+int lg4ff_deinit(struct hid_device *hdev);
+#else
+static inline int lg4ff_adjust_input_event(struct hid_device *hid, struct hid_field *field,
+					   struct hid_usage *usage, __s32 value, struct lg_drv_data *drv_data) { return 0; }
+static inline int lg4ff_init(struct hid_device *hdev) { return -1; }
+static inline int lg4ff_deinit(struct hid_device *hdev) { return -1; }
+#endif
+
+#endif