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[v2,3/4] Input: wm9712: Fix wrong pen up readings

Message ID 1362848753-6725-4-git-send-email-mpa@pengutronix.de (mailing list archive)
State New, archived
Headers show

Commit Message

Markus Pargmann March 9, 2013, 5:05 p.m. UTC 
Often a reading can be wrong. This patch assures that this is really a
pen up event and not a false reading.

Based on wm9712: pen up by Teresa Gámez and Christian Hemp.

Cc: Teresa Gámez <t.gamez@phytec.de>
Cc: Christian Hemp <c.hemp@phytec.de>
Cc: stable@vger.kernel.org
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
---
 drivers/input/touchscreen/wm9712.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/input/touchscreen/wm9712.c b/drivers/input/touchscreen/wm9712.c
index a983da1..3b4eed4 100644
--- a/drivers/input/touchscreen/wm9712.c
+++ b/drivers/input/touchscreen/wm9712.c
@@ -302,8 +302,12 @@  static int wm9712_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
 	}
 
 	if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
-		wm->pen_probably_down = 0;
-		return RC_PENUP;
+		/* Sometimes it reads a wrong value the first time. */
+		*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
+		if (!(*sample & WM97XX_PEN_DOWN)) {
+			wm->pen_probably_down = 0;
+			return RC_PENUP;
+		}
 	}
 
 	return RC_VALID;