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>

2 files changed, 16 insertions, 0 deletions

diff --git a/include/linux/input.h b/include/linux/input.h
index 99e2a52c0509..6de145df4c1c 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -848,6 +848,7 @@ struct input_keymap_entry {
  */
 #define MT_TOOL_FINGER          0
 #define MT_TOOL_PEN             1
+#define MT_TOOL_MAX             1
 
 /*
  * Values describing the status of a force-feedback effect
@@ -1122,6 +1123,7 @@ struct ff_effect {
  *      of tracked contacts
  * @mtsize: number of MT slots the device uses
  * @slot: MT slot currently being transmitted
+ * @trkid: stores MT tracking ID for the current contact
  * @absinfo: array of &struct absinfo elements holding information
  *      about absolute axes (current value, min, max, flat, fuzz,
  *      resolution)
@@ -1206,6 +1208,7 @@ struct input_dev {
         struct input_mt_slot *mt;
         int mtsize;
         int slot;
+        int trkid;
 
         struct input_absinfo *absinfo;
 
diff --git a/include/linux/input/mt.h b/include/linux/input/mt.h
index d7f6518e3222..b3ac06a4435d 100644
--- a/include/linux/input/mt.h
+++ b/include/linux/input/mt.h
@@ -13,6 +13,8 @@
 
 #include <linux/input.h>
 
+#define TRKID_MAX       0xffff
+
 /**
  * struct input_mt_slot - represents the state of an input MT slot
  * @abs: holds current values of ABS_MT axes for this slot
@@ -36,9 +38,20 @@ static inline int input_mt_get_value(const struct input_mt_slot *slot,
 int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots);
 void input_mt_destroy_slots(struct input_dev *dev);
 
+static inline int input_mt_new_trkid(struct input_dev *dev)
+{
+        return dev->trkid++ & TRKID_MAX;
+}
+
 static inline void input_mt_slot(struct input_dev *dev, int slot)
 {
         input_event(dev, EV_ABS, ABS_MT_SLOT, slot);
 }
 
+void input_mt_report_slot_state(struct input_dev *dev,
+                                unsigned int tool_type, bool active);
+
+void input_mt_report_finger_count(struct input_dev *dev, int count);
+void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count);
+
 #endif