[PATCH v2] input: goodix: Check the 'buffer status' bit before reading data

[PATCH v2] input: goodix: Check the 'buffer status' bit before reading data

[Paul Cercueil]

The MSB of the first byte read via I2C at the coordinates address
indicates whether the data is valid or ready (called "buffer status" in
the datasheets) when an interrupt is raised. Previously, this bit was
ignored, which resulted in a lot of incorrect detections of "finger
removed" events.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
v2: Fix commit message

 drivers/input/touchscreen/goodix.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
index ca19668..9fa6c5f 100644
--- a/drivers/input/touchscreen/goodix.c
+++ b/drivers/input/touchscreen/goodix.c
@@ -98,6 +98,9 @@ static int goodix_ts_read_input_report(struct goodix_ts_data *ts, u8 *data)
 		return error;
 	}
 
+	if (!(data[0] & 0x80))
+		return -EAGAIN;
+
 	touch_num = data[0] & 0x0f;
 	if (touch_num > GOODIX_MAX_CONTACTS)
 		return -EPROTO;
-- 
2.1.4

Re: [PATCH v2] input: goodix: Check the 'buffer status' bit before reading data

[Bastien Nocera]

On Fri, 2015-05-01 at 14:40 +0200, Paul Cercueil wrote:
> The MSB of the first byte read via I2C at the coordinates address
> indicates whether the data is valid or ready (called "buffer status" 
> in
> the datasheets) when an interrupt is raised. Previously, this bit was
> ignored, which resulted in a lot of incorrect detections of "finger
> removed" events.
> 
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>

Signed-off-by: Bastien Nocera <hadess@hadess.net>

Re: [PATCH v2] input: goodix: Check the 'buffer status' bit before reading data

[Dmitry Torokhov]

On Fri, May 01, 2015 at 04:13:55PM +0200, Bastien Nocera wrote:
> On Fri, 2015-05-01 at 14:40 +0200, Paul Cercueil wrote:
> > The MSB of the first byte read via I2C at the coordinates address
> > indicates whether the data is valid or ready (called "buffer status" 
> > in
> > the datasheets) when an interrupt is raised. Previously, this bit was
> > ignored, which resulted in a lot of incorrect detections of "finger
> > removed" events.
> > 
> > Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> 
> Signed-off-by: Bastien Nocera <hadess@hadess.net>

Applied, thank you.

-- 
Dmitry