Renamed "w" into "red_cost_matrix" for readability.
Add docs and comments to detail what the code is expected to do.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
---
drivers/input/input-mt.c | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index b6ee42a..b269113 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -359,23 +359,41 @@ static int input_mt_set_matrix(struct input_mt *mt,
return w - mt->red;
}
+/**
+ * input_mt_set_slots() - assign slots to the list of pos thanks to the reduced
+ * cost matrix
+ * @mt: the input_mt handle of the current device
+ * @slots: the slot assignment to be filled
+ * @num_pos: number of positions
+ *
+ * For each given touch in pos, try to match the touch to a previous one.
+ * Then, assign new slots to those who were not a match with the previously
+ * sent slots.
+ */
static void input_mt_set_slots(struct input_mt *mt,
int *slots, int num_pos)
{
struct input_mt_slot *s;
- int *w = mt->red, *p;
+ int *red_cost_matrix = mt->red;
+ int *p;
+ /* first initialise the output values to -1 */
for (p = slots; p != slots + num_pos; p++)
*p = -1;
+ /* for each currently active slot, match it with one of the touch
+ * in the pos array */
for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
if (!input_mt_is_active(s))
continue;
for (p = slots; p != slots + num_pos; p++)
- if (*w++ < 0)
+ if (*red_cost_matrix++ < 0)
+ /* we have a match, store the slot value
+ * in pos[i] */
*p = s - mt->slots;
}
+ /* for each unassigned touch in pos, assign a new slot for it */
for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
if (input_mt_is_active(s))
continue;
--
2.1.0
--
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