HID: wacom: peport In Range event according to the spec

Some Cintiq and Intuos tablets report In Range event. This event is sent before
valid data is reported when tool enters proximity; or before out of proximity
event is reported when tool exits.

While entering proximity, In Range means a pen is detected. This information
can be used for palm/touch rejection on both pen and touch enabled devices.
While exiting, it means the tool has reached its maximum detectable distance.
Signed-off-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/wacom_wac.c

@@ -443,9 +443,6 @@ static int wacom_intuos_inout(struct wacom_wac *wacom)
 
 	/* Enter report */
 	if ((data[1] & 0xfc) == 0xc0) {
-		if (features->quirks & WACOM_QUIRK_MULTI_INPUT)
-			wacom->shared->stylus_in_proximity = true;
-
 		/* serial number of the tool */
 		wacom->serial[idx] = ((data[3] & 0x0f) << 28) +
 			(data[4] << 20) + (data[5] << 12) +
@@ -554,19 +551,22 @@ static int wacom_intuos_inout(struct wacom_wac *wacom)
 	   (features->type == CINTIQ && !(data[1] & 0x40)))
 		return 1;
 
-	/* Range Report */
-	if ((data[1] & 0xfe) == 0x20) {
+	if (features->quirks & WACOM_QUIRK_MULTI_INPUT)
+		wacom->shared->stylus_in_proximity = true;
+
+	/* in Range while exiting */
+	if (((data[1] & 0xfe) == 0x20) && wacom->reporting_data) {
 		input_report_key(input, BTN_TOUCH, 0);
 		input_report_abs(input, ABS_PRESSURE, 0);
 		input_report_abs(input, ABS_DISTANCE, wacom->features.distance_max);
-		if (features->quirks & WACOM_QUIRK_MULTI_INPUT)
-			wacom->shared->stylus_in_proximity = true;
+		return 2;
 	}
 
 	/* Exit report */
 	if ((data[1] & 0xfe) == 0x80) {
 		if (features->quirks & WACOM_QUIRK_MULTI_INPUT)
 			wacom->shared->stylus_in_proximity = false;
+		wacom->reporting_data = false;
 
 		/* don't report exit if we don't know the ID */
 		if (!wacom->id[idx])
@@ -952,6 +952,7 @@ static int wacom_intuos_irq(struct wacom_wac *wacom)
 	input_report_abs(input, ABS_MISC, wacom->id[idx]); /* report tool id */
 	input_report_key(input, wacom->tool[idx], 1);
 	input_event(input, EV_MSC, MSC_SERIAL, wacom->serial[idx]);
+	wacom->reporting_data = true;
 	return 1;
 }
 

drivers/hid/wacom_wac.h

@@ -189,6 +189,7 @@ struct wacom_wac {
 	int tool[2];
 	int id[2];
 	__u32 serial[2];
+	bool reporting_data;
 	struct wacom_features features;
 	struct wacom_shared *shared;
 	struct input_dev *input;