From 1ff2e1a44e02d4bdbb9be67c7d9acc240a67141f Mon Sep 17 00:00:00 2001 From: Harry Cutts Date: Thu, 30 Aug 2018 14:56:19 -0700 Subject: HID: input: Create a utility class for counting scroll events To avoid code duplication, this class counts high-resolution scroll movements and emits the legacy low-resolution events when appropriate. Drivers should be able to create one instance for each scroll wheel that they need to handle. Signed-off-by: Harry Cutts Reviewed-by: Benjamin Tissoires Signed-off-by: Jiri Kosina --- include/linux/hid.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'include/linux/hid.h') diff --git a/include/linux/hid.h b/include/linux/hid.h index 834e6461a690..037e37b0b0e6 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -1138,6 +1138,34 @@ 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); -- cgit