From: James Hughes <james.hughes@raspberrypi.org>
Date: Fri, 22 Sep 2017 09:24:04 +0000 (+0100)
Subject: Touchscreen spurious event fix
X-Git-Tag: archive/raspbian/4.9.51-1+rpi1~5^2~144
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=7b7b07acd4d15e048d86e766eed9fb21f3ad210e;p=linux-4.9.git

Touchscreen spurious event fix

Touchscreen driver was not checking event type,
which meant bad coords that arrived with the
finger up event were being used, causing this
spurious coordinate event.

Fix is to ignore all finger up events.

Signed-off-by: James Hughes <james.hughes@raspberrypi.org>
---

diff --git a/drivers/input/touchscreen/rpi-ft5406.c b/drivers/input/touchscreen/rpi-ft5406.c
index 9d7d05482355..ab35716caafa 100644
--- a/drivers/input/touchscreen/rpi-ft5406.c
+++ b/drivers/input/touchscreen/rpi-ft5406.c
@@ -42,6 +42,9 @@ struct ft5406_regs {
 
 #define SCREEN_WIDTH  800
 #define SCREEN_HEIGHT 480
+#define FTS_TOUCH_DOWN      0
+#define FTS_TOUCH_UP        1
+#define FTS_TOUCH_CONTACT   2
 
 struct ft5406 {
 	struct platform_device * pdev;
@@ -81,18 +84,22 @@ static int ft5406_thread(void *arg)
 				int x = (((int) regs.point[i].xh & 0xf) << 8) + regs.point[i].xl;
 				int y = (((int) regs.point[i].yh & 0xf) << 8) + regs.point[i].yl;
 				int touchid = (regs.point[i].yh >> 4) & 0xf;
+				int event_id = (regs.point[i].xh >> 6) & 0x3;
 				
 				modified_ids |= 1 << touchid;
 
-				if(!((1 << touchid) & known_ids))
-					dev_dbg(&ts->pdev->dev, "x = %d, y = %d, touchid = %d\n", x, y, touchid);
-				
-				input_mt_slot(ts->input_dev, touchid);
-				input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, 1);
+				if (event_id == FTS_TOUCH_CONTACT ||
+					event_id == FTS_TOUCH_DOWN) {
+					if(!((1 << touchid) & known_ids))
+						dev_dbg(&ts->pdev->dev, "x = %d, y = %d, touchid = %d\n",
+								x, y, touchid);
 
-				input_report_abs(ts->input_dev, ABS_MT_POSITION_X, x);
-				input_report_abs(ts->input_dev, ABS_MT_POSITION_Y, y);
+					input_mt_slot(ts->input_dev, touchid);
+					input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, 1);
 
+					input_report_abs(ts->input_dev, ABS_MT_POSITION_X, x);
+					input_report_abs(ts->input_dev, ABS_MT_POSITION_Y, y);
+				}
 			}
 
 			released_ids = known_ids & ~modified_ids;
@@ -100,7 +107,8 @@ static int ft5406_thread(void *arg)
 			{
 				if(released_ids & (1<<i))
 				{
-					dev_dbg(&ts->pdev->dev, "Released %d, known = %x modified = %x\n", i, known_ids, modified_ids);
+					dev_dbg(&ts->pdev->dev, "Released %d, known = %x modified = %x\n",
+							i, known_ids, modified_ids);
 					input_mt_slot(ts->input_dev, i);
 					input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, 0);
 					modified_ids &= ~(1 << i);