3 files changed, 129 insertions, 43 deletions

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index cd323254ca6f..fc5afbd78625 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -686,6 +686,10 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
                                                                   sizeof(struct input_absinfo))))
                                         return -EFAULT;
 
+                                /* We can't change number of reserved MT slots */
+                                if (t == ABS_MT_SLOT)
+                                        return -EINVAL;
+
                                 /*
                                  * Take event lock to ensure that we are not
                                  * changing device parameters in the middle
diff --git a/drivers/input/input.c b/drivers/input/input.c
index a3d5485154e7..54109c33e36c 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -33,25 +33,6 @@ MODULE_LICENSE("GPL");
 
 #define INPUT_DEVICES   256
 
-/*
- * EV_ABS events which should not be cached are listed here.
- */
-static unsigned int input_abs_bypass_init_data[] __initdata = {
-        ABS_MT_TOUCH_MAJOR,
-        ABS_MT_TOUCH_MINOR,
-        ABS_MT_WIDTH_MAJOR,
-        ABS_MT_WIDTH_MINOR,
-        ABS_MT_ORIENTATION,
-        ABS_MT_POSITION_X,
-        ABS_MT_POSITION_Y,
-        ABS_MT_TOOL_TYPE,
-        ABS_MT_BLOB_ID,
-        ABS_MT_TRACKING_ID,
-        ABS_MT_PRESSURE,
-        0
-};
-static unsigned long input_abs_bypass[BITS_TO_LONGS(ABS_CNT)];
-
 static LIST_HEAD(input_dev_list);
 static LIST_HEAD(input_handler_list);
 
@@ -181,6 +162,56 @@ static void input_stop_autorepeat(struct input_dev *dev)
 #define INPUT_PASS_TO_DEVICE    2
 #define INPUT_PASS_TO_ALL       (INPUT_PASS_TO_HANDLERS | INPUT_PASS_TO_DEVICE)
 
+static int input_handle_abs_event(struct input_dev *dev,
+                                  unsigned int code, int *pval)
+{
+        bool is_mt_event;
+        int *pold;
+
+        if (code == ABS_MT_SLOT) {
+                /*
+                 * "Stage" the event; we'll flush it later, when we
+                 * get actiual touch data.
+                 */
+                if (*pval >= 0 && *pval < dev->mtsize)
+                        dev->slot = *pval;
+
+                return INPUT_IGNORE_EVENT;
+        }
+
+        is_mt_event = code >= ABS_MT_FIRST && code <= ABS_MT_LAST;
+
+        if (!is_mt_event) {
+                pold = &dev->abs[code];
+        } else if (dev->mt) {
+                struct input_mt_slot *mtslot = &dev->mt[dev->slot];
+                pold = &mtslot->abs[code - ABS_MT_FIRST];
+        } else {
+                /*
+                 * Bypass filtering for multitouch events when
+                 * not employing slots.
+                 */
+                pold = NULL;
+        }
+
+        if (pold) {
+                *pval = input_defuzz_abs_event(*pval, *pold,
+                                                dev->absfuzz[code]);
+                if (*pold == *pval)
+                        return INPUT_IGNORE_EVENT;
+
+                *pold = *pval;
+        }
+
+        /* Flush pending "slot" event */
+        if (is_mt_event && dev->slot != dev->abs[ABS_MT_SLOT]) {
+                dev->abs[ABS_MT_SLOT] = dev->slot;
+                input_pass_event(dev, EV_ABS, ABS_MT_SLOT, dev->slot);
+        }
+
+        return INPUT_PASS_TO_HANDLERS;
+}
+
 static void input_handle_event(struct input_dev *dev,
                                unsigned int type, unsigned int code, int value)
 {
@@ -233,21 +264,9 @@ static void input_handle_event(struct input_dev *dev,
                 break;
 
         case EV_ABS:
-                if (is_event_supported(code, dev->absbit, ABS_MAX)) {
-
-                        if (test_bit(code, input_abs_bypass)) {
-                                disposition = INPUT_PASS_TO_HANDLERS;
-                                break;
-                        }
+                if (is_event_supported(code, dev->absbit, ABS_MAX))
+                        disposition = input_handle_abs_event(dev, code, &value);
 
-                        value = input_defuzz_abs_event(value,
-                                        dev->abs[code], dev->absfuzz[code]);
-
-                        if (dev->abs[code] != value) {
-                                dev->abs[code] = value;
-                                disposition = INPUT_PASS_TO_HANDLERS;
-                        }
-                }
                 break;
 
         case EV_REL:
@@ -1288,6 +1307,7 @@ static void input_dev_release(struct device *device)
         struct input_dev *dev = to_input_dev(device);
 
         input_ff_destroy(dev);
+        input_mt_destroy_slots(dev);
         kfree(dev);
 
         module_put(THIS_MODULE);
@@ -1537,6 +1557,45 @@ void input_free_device(struct input_dev *dev)
 EXPORT_SYMBOL(input_free_device);
 
 /**
+ * input_mt_create_slots() - create MT input slots
+ * @dev: input device supporting MT events and finger tracking
+ * @num_slots: number of slots used by the device
+ *
+ * This function allocates all necessary memory for MT slot handling
+ * in the input device, and adds ABS_MT_SLOT to the device capabilities.
+ */
+int input_mt_create_slots(struct input_dev *dev, unsigned int num_slots)
+{
+        if (!num_slots)
+                return 0;
+
+        dev->mt = kcalloc(num_slots, sizeof(struct input_mt_slot), GFP_KERNEL);
+        if (!dev->mt)
+                return -ENOMEM;
+
+        dev->mtsize = num_slots;
+        input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
+
+        return 0;
+}
+EXPORT_SYMBOL(input_mt_create_slots);
+
+/**
+ * input_mt_destroy_slots() - frees the MT slots of the input device
+ * @dev: input device with allocated MT slots
+ *
+ * This function is only needed in error path as the input core will
+ * automatically free the MT slots when the device is destroyed.
+ */
+void input_mt_destroy_slots(struct input_dev *dev)
+{
+        kfree(dev->mt);
+        dev->mt = NULL;
+        dev->mtsize = 0;
+}
+EXPORT_SYMBOL(input_mt_destroy_slots);
+
+/**
  * input_set_capability - mark device as capable of a certain event
  * @dev: device that is capable of emitting or accepting event
  * @type: type of the event (EV_KEY, EV_REL, etc...)
@@ -1945,20 +2004,10 @@ static const struct file_operations input_fops = {
         .open = input_open_file,
 };
 
-static void __init input_init_abs_bypass(void)
-{
-        const unsigned int *p;
-
-        for (p = input_abs_bypass_init_data; *p; p++)
-                input_abs_bypass[BIT_WORD(*p)] |= BIT_MASK(*p);
-}
-
 static int __init input_init(void)
 {
         int err;
 
-        input_init_abs_bypass();
-
         err = class_register(&input_class);
         if (err) {
                 printk(KERN_ERR "input: unable to register input_dev class\n");
diff --git a/include/linux/input.h b/include/linux/input.h
index cc524c8b6703..a14de64ed16a 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -691,9 +691,12 @@ struct input_absinfo {
 #define ABS_TILT_X              0x1a
 #define ABS_TILT_Y              0x1b
 #define ABS_TOOL_WIDTH          0x1c
+
 #define ABS_VOLUME              0x20
+
 #define ABS_MISC                0x28
 
+#define ABS_MT_SLOT             0x2f    /* MT slot being modified */
 #define ABS_MT_TOUCH_MAJOR      0x30    /* Major axis of touching ellipse */
 #define ABS_MT_TOUCH_MINOR      0x31    /* Minor axis (omit if circular) */
 #define ABS_MT_WIDTH_MAJOR      0x32    /* Major axis of approaching ellipse */
@@ -706,6 +709,12 @@ struct input_absinfo {
 #define ABS_MT_TRACKING_ID      0x39    /* Unique ID of initiated contact */
 #define ABS_MT_PRESSURE         0x3a    /* Pressure on contact area */
 
+#ifdef __KERNEL__
+/* Implementation details, userspace should not care about these */
+#define ABS_MT_FIRST            ABS_MT_TOUCH_MAJOR
+#define ABS_MT_LAST             ABS_MT_PRESSURE
+#endif
+
 #define ABS_MAX                 0x3f
 #define ABS_CNT                 (ABS_MAX+1)
 
@@ -1048,6 +1057,14 @@ struct ff_effect {
 #include <linux/mod_devicetable.h>
 
 /**
+ * struct input_mt_slot - represents the state of an input MT slot
+ * @abs: holds current values of ABS_MT axes for this slot
+ */
+struct input_mt_slot {
+        int abs[ABS_MT_LAST - ABS_MT_FIRST + 1];
+};
+
+/**
  * struct input_dev - represents an input device
  * @name: name of the device
  * @phys: physical path to the device in the system hierarchy
@@ -1085,6 +1102,10 @@ struct ff_effect {
  * @sync: set to 1 when there were no new events since last EV_SYNC
  * @abs: current values for reports from absolute axes
  * @rep: current values for autorepeat parameters (delay, rate)
+ * @mt: pointer to array of struct input_mt_slot holding current values
+ *      of tracked contacts
+ * @mtsize: number of MT slots the device uses
+ * @slot: MT slot currently being transmitted
  * @key: reflects current state of device's keys/buttons
  * @led: reflects current state of device's LEDs
  * @snd: reflects current state of sound effects
@@ -1164,6 +1185,10 @@ struct input_dev {
         int abs[ABS_CNT];
         int rep[REP_MAX + 1];
 
+        struct input_mt_slot *mt;
+        int mtsize;
+        int slot;
+
         unsigned long key[BITS_TO_LONGS(KEY_CNT)];
         unsigned long led[BITS_TO_LONGS(LED_CNT)];
         unsigned long snd[BITS_TO_LONGS(SND_CNT)];
@@ -1412,6 +1437,11 @@ static inline void input_mt_sync(struct input_dev *dev)
         input_event(dev, EV_SYN, SYN_MT_REPORT, 0);
 }
 
+static inline void input_mt_slot(struct input_dev *dev, int slot)
+{
+        input_event(dev, EV_ABS, ABS_MT_SLOT, slot);
+}
+
 void input_set_capability(struct input_dev *dev, unsigned int type, unsigned int code);
 
 /**
@@ -1506,5 +1536,8 @@ int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file);
 int input_ff_create_memless(struct input_dev *dev, void *data,
                 int (*play_effect)(struct input_dev *, void *, struct ff_effect *));
 
+int input_mt_create_slots(struct input_dev *dev, unsigned int num_slots);
+void input_mt_destroy_slots(struct input_dev *dev);
+
 #endif
 #endif