input: mt: Move tracking and pointer emulation to input-mt

The drivers using the type B protocol all report tracking information
the same way. The contact id is semantically equivalent to
ABS_MT_SLOT, and the handling of ABS_MT_TRACKING_ID only complicates
the driver. The situation can be improved upon by providing a common
pointer emulation code, thereby removing the need for the tracking id
in the driver.  This patch moves all tracking event handling over to
the input core, simplifying both the existing drivers and the ones
currently in preparation.

Acked-by: Ping Cheng <pingc@wacom.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>

1 files changed, 2 insertions, 28 deletions

diff --git a/drivers/hid/hid-3m-pct.c b/drivers/hid/hid-3m-pct.c
index ea475964d05a..4fb7c7528d16 100644
--- a/drivers/hid/hid-3m-pct.c
+++ b/drivers/hid/hid-3m-pct.c
@@ -28,7 +28,6 @@ MODULE_LICENSE("GPL");
 #include "hid-ids.h"
 
 #define MAX_SLOTS               60
-#define MAX_TRKID               USHRT_MAX
 
 /* estimated signal-to-noise ratios */
 #define SN_MOVE                 2048
@@ -36,14 +35,11 @@ MODULE_LICENSE("GPL");
 
 struct mmm_finger {
         __s32 x, y, w, h;
-        __u16 id;
-        bool prev_touch;
         bool touch, valid;
 };
 
 struct mmm_data {
         struct mmm_finger f[MAX_SLOTS];
-        __u16 id;
         __u8 curid;
         __u8 nexp, nreal;
         bool touch, valid;
@@ -117,11 +113,6 @@ static int mmm_input_mapping(struct hid_device *hdev, struct hid_input *hi,
                                         0, 1, 0, 0);
                         return 1;
                 case HID_DG_CONTACTID:
-                        field->logical_maximum = MAX_TRKID;
-                        hid_map_usage(hi, usage, bit, max,
-                                        EV_ABS, ABS_MT_TRACKING_ID);
-                        input_set_abs_params(hi->input, ABS_MT_TRACKING_ID,
-                                             0, MAX_TRKID, 0, 0);
                         input_mt_init_slots(hi->input, MAX_SLOTS);
                         return 1;
                 }
@@ -152,7 +143,6 @@ static int mmm_input_mapped(struct hid_device *hdev, struct hid_input *hi,
  */
 static void mmm_filter_event(struct mmm_data *md, struct input_dev *input)
 {
-        struct mmm_finger *oldest = 0;
         int i;
         for (i = 0; i < MAX_SLOTS; ++i) {
                 struct mmm_finger *f = &md->f[i];
@@ -161,6 +151,7 @@ static void mmm_filter_event(struct mmm_data *md, struct input_dev *input)
                         continue;
                 }
                 input_mt_slot(input, i);
+                input_mt_report_slot_state(input, MT_TOOL_FINGER, f->touch);
                 if (f->touch) {
                         /* this finger is on the screen */
                         int wide = (f->w > f->h);
@@ -168,33 +159,16 @@ static void mmm_filter_event(struct mmm_data *md, struct input_dev *input)
                         int major = max(f->w, f->h) >> 1;
                         int minor = min(f->w, f->h) >> 1;
 
-                        if (!f->prev_touch)
-                                f->id = md->id++;
-                        input_event(input, EV_ABS, ABS_MT_TRACKING_ID, f->id);
                         input_event(input, EV_ABS, ABS_MT_POSITION_X, f->x);
                         input_event(input, EV_ABS, ABS_MT_POSITION_Y, f->y);
                         input_event(input, EV_ABS, ABS_MT_ORIENTATION, wide);
                         input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, major);
                         input_event(input, EV_ABS, ABS_MT_TOUCH_MINOR, minor);
-                        /* touchscreen emulation: pick the oldest contact */
-                        if (!oldest || ((f->id - oldest->id) & (SHRT_MAX + 1)))
-                                oldest = f;
-                } else {
-                        /* this finger took off the screen */
-                        input_event(input, EV_ABS, ABS_MT_TRACKING_ID, -1);
                 }
-                f->prev_touch = f->touch;
                 f->valid = 0;
         }
 
-        /* touchscreen emulation */
-        if (oldest) {
-                input_event(input, EV_KEY, BTN_TOUCH, 1);
-                input_event(input, EV_ABS, ABS_X, oldest->x);
-                input_event(input, EV_ABS, ABS_Y, oldest->y);
-        } else {
-                input_event(input, EV_KEY, BTN_TOUCH, 0);
-        }
+        input_mt_report_pointer_emulation(input, true);
         input_sync(input);
 }