Revert "HID: input: Create a utility class for counting scroll events"

This reverts commit 1ff2e1a44e02d4bdbb9be67c7d9acc240a67141f.

It turns out the current API is not that compatible with
some Microsoft mice, so better start again from scratch.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Harry Cutts <hcutts@chromium.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-input.c

@@ -1841,48 +1841,3 @@ void hidinput_disconnect(struct hid_device *hid)
 }
 EXPORT_SYMBOL_GPL(hidinput_disconnect);
 
-/**
- * hid_scroll_counter_handle_scroll() - Send high- and low-resolution scroll
- *                                      events given a high-resolution wheel
- *                                      movement.
- * @counter: a hid_scroll_counter struct describing the wheel.
- * @hi_res_value: the movement of the wheel, in the mouse's high-resolution
- *                units.
- *
- * Given a high-resolution movement, this function converts the movement into
- * microns and emits high-resolution scroll events for the input device. It also
- * uses the multiplier from &struct hid_scroll_counter to emit low-resolution
- * scroll events when appropriate for backwards-compatibility with userspace
- * input libraries.
- */
-void hid_scroll_counter_handle_scroll(struct hid_scroll_counter *counter,
-				      int hi_res_value)
-{
-	int low_res_scroll_amount;
-	/* Some wheels will rest 7/8ths of a notch from the previous notch
-	 * after slow movement, so we want the threshold for low-res events to
-	 * be in the middle of the notches (e.g. after 4/8ths) as opposed to on
-	 * the notches themselves (8/8ths).
-	 */
-	int threshold = counter->resolution_multiplier / 2;
-
-	input_report_rel(counter->dev, REL_WHEEL_HI_RES,
-			 hi_res_value * counter->microns_per_hi_res_unit);
-
-	counter->remainder += hi_res_value;
-	if (abs(counter->remainder) >= threshold) {
-		/* Add (or subtract) 1 because we want to trigger when the wheel
-		 * is half-way to the next notch (i.e. scroll 1 notch after a
-		 * 1/2 notch movement, 2 notches after a 1 1/2 notch movement,
-		 * etc.).
-		 */
-		low_res_scroll_amount =
-			counter->remainder / counter->resolution_multiplier
-			+ (hi_res_value > 0 ? 1 : -1);
-		input_report_rel(counter->dev, REL_WHEEL,
-				 low_res_scroll_amount);
-		counter->remainder -=
-			low_res_scroll_amount * counter->resolution_multiplier;
-	}
-}
-EXPORT_SYMBOL_GPL(hid_scroll_counter_handle_scroll);

include/linux/hid.h

@@ -1139,34 +1139,6 @@ static inline u32 hid_report_len(struct hid_report *report)
 int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size,
 		int interrupt);
 
-
-/**
- * struct hid_scroll_counter - Utility class for processing high-resolution
- *                             scroll events.
- * @dev: the input device for which events should be reported.
- * @microns_per_hi_res_unit: the amount moved by the user's finger for each
- *                           high-resolution unit reported by the mouse, in
- *                           microns.
- * @resolution_multiplier: the wheel's resolution in high-resolution mode as a
- *                         multiple of its lower resolution. For example, if
- *                         moving the wheel by one "notch" would result in a
- *                         value of 1 in low-resolution mode but 8 in
- *                         high-resolution, the multiplier is 8.
- * @remainder: counts the number of high-resolution units moved since the last
- *             low-resolution event (REL_WHEEL or REL_HWHEEL) was sent. Should
- *             only be used by class methods.
- */
-struct hid_scroll_counter {
-	struct input_dev *dev;
-	int microns_per_hi_res_unit;
-	int resolution_multiplier;
-
-	int remainder;
-};
-
-void hid_scroll_counter_handle_scroll(struct hid_scroll_counter *counter,
-				      int hi_res_value);
-
 /* HID quirks API */
 unsigned long hid_lookup_quirk(const struct hid_device *hdev);
 int hid_quirks_init(char **quirks_param, __u16 bus, int count);