Some devices use an internal key for tracking which cannot be directly
mapped to slots. This patch provides a key-to-slot mapping, which can
be used by drivers of such devices.
Signed-off-by: Henrik Rydberg <rydberg@xxxxxxxxxxx>
---
drivers/input/input-mt.c | 32 ++++++++++++++++++++++++++++++++
include/linux/input/mt.h | 4 ++++
2 files changed, 36 insertions(+)
diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index 2acf693..4c0e531 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -384,3 +384,35 @@ int input_mt_assign_slots(struct input_dev *dev, int *slots,
return 0;
}
EXPORT_SYMBOL(input_mt_assign_slots);
+
+/**
+ * input_mt_get_slot_by_key() - return slot matching key
+ * @dev: input device with allocated MT slots
+ * @key: the key of the sought slot
+ *
+ * Returns the slot of the given key, if it exists, otherwise
+ * set the key on the first unused slot and return.
+ *
+ * If no available slot can be found, -1 is returned.
+ */
+int input_mt_get_slot_by_key(struct input_dev *dev, int key)
+{
+ struct input_mt *mt = dev->mt;
+ struct input_mt_slot *s;
+
+ if (!mt)
+ return -1;
+
+ for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
+ if (input_mt_is_active(s) && s->key == key)
+ return s - mt->slots;
+
+ for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
+ if (!input_mt_is_active(s)) {
+ s->key = key;
+ return s - mt->slots;
+ }
+
+ return -1;
+}
+EXPORT_SYMBOL(input_mt_get_slot_by_key);
diff --git a/include/linux/input/mt.h b/include/linux/input/mt.h
index 10bb77c..bbdc694 100644
--- a/include/linux/input/mt.h
+++ b/include/linux/input/mt.h
@@ -24,10 +24,12 @@
* struct input_mt_slot - represents the state of an input MT slot
* @abs: holds current values of ABS_MT axes for this slot
* @frame: last frame at which input_mt_report_slot_state() was called
+ * @key: optional driver designation of this slot
*/
struct input_mt_slot {
int abs[ABS_MT_LAST - ABS_MT_FIRST + 1];
unsigned int frame;
+ unsigned int key;
};
/**
@@ -109,4 +111,6 @@ struct input_mt_pos {
int input_mt_assign_slots(struct input_dev *dev, int *slots,
const struct input_mt_pos *pos, int num_pos);
+int input_mt_get_slot_by_key(struct input_dev *dev, int key);
+
#endif
--
1.7.12
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