[PATCH 13/18] Input: MT - toggle ABS_PRESSURE pointer emulation

[Angela Czubak <acz@xxxxxxxxxxxx>]

Add a function to switch off ABS_PRESSURE generation if necessary.
This may be helpful in case drivers want to generate ABS_PRESSURE events
themselves from ABS_MT_PRESSURE.

Signed-off-by: Angela Czubak <acz@xxxxxxxxxxxx>
---
 drivers/input/input-mt.c | 18 ++++++++++++++++--
 include/linux/input/mt.h |  4 ++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index 44fe6f2f063c..e0bf5917a8b5 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -52,6 +52,7 @@ int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
 
 	mt->num_slots = num_slots;
 	mt->flags = flags;
+	mt->abs_pressure_gen = true;
 	input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
 	input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);
 
@@ -244,12 +245,14 @@ void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
 		input_event(dev, EV_ABS, ABS_X, x);
 		input_event(dev, EV_ABS, ABS_Y, y);
 
-		if (test_bit(ABS_MT_PRESSURE, dev->absbit)) {
+		if (test_bit(ABS_MT_PRESSURE, dev->absbit) &&
+		    mt->abs_pressure_gen) {
 			int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
 			input_event(dev, EV_ABS, ABS_PRESSURE, p);
 		}
 	} else {
-		if (test_bit(ABS_MT_PRESSURE, dev->absbit))
+		if (test_bit(ABS_MT_PRESSURE, dev->absbit) &&
+		    mt->abs_pressure_gen)
 			input_event(dev, EV_ABS, ABS_PRESSURE, 0);
 	}
 }
@@ -312,6 +315,17 @@ void input_mt_sync_frame(struct input_dev *dev)
 }
 EXPORT_SYMBOL(input_mt_sync_frame);
 
+void input_mt_pressure_toggle(struct input_dev *dev, bool toggle)
+{
+	struct input_mt *mt = dev->mt;
+
+	if (!mt)
+		return;
+
+	mt->abs_pressure_gen = toggle;
+}
+EXPORT_SYMBOL(input_mt_pressure_toggle);
+
 static int adjust_dual(int *begin, int step, int *end, int eq, int mu)
 {
 	int f, *p, s, c;
diff --git a/include/linux/input/mt.h b/include/linux/input/mt.h
index 3b8580bd33c1..c870a513bde1 100644
--- a/include/linux/input/mt.h
+++ b/include/linux/input/mt.h
@@ -38,6 +38,7 @@ struct input_mt_slot {
  * @flags: input_mt operation flags
  * @frame: increases every time input_mt_sync_frame() is called
  * @red: reduced cost matrix for in-kernel tracking
+ * @abs_pressure_gen: emulate pointer pressure
  * @slots: array of slots holding current values of tracked contacts
  */
 struct input_mt {
@@ -47,6 +48,7 @@ struct input_mt {
 	unsigned int flags;
 	unsigned int frame;
 	int *red;
+	bool abs_pressure_gen;
 	struct input_mt_slot slots[];
 };
 
@@ -111,6 +113,8 @@ void input_mt_drop_unused(struct input_dev *dev);
 
 void input_mt_sync_frame(struct input_dev *dev);
 
+void input_mt_pressure_toggle(struct input_dev *dev, bool toggle);
+
 /**
  * struct input_mt_pos - contact position
  * @x: horizontal coordinate
-- 
2.34.1.307.g9b7440fafd-goog