From 9378c0251c7ac4b247177fb0c292a025ca1b751c Mon Sep 17 00:00:00 2001 From: Franklin S Cooper Jr Date: Fri, 16 Oct 2015 15:34:41 -0700 Subject: Input: edt-ft5x06 - work around FT5506 firmware bug In the touchscreen controller ISR, reading the tsc starting from register 0x2 causes the tsc to infrequently update the detected finger's x and y coordinate. The irq pin toggles at a fast rate to indicate touch events are happening. However, the tsc on average updates the touch point's x and y value every ~100 ms which is much slower than the advertised rate of 100+ Hz. This leads to multiple reads within this ~100 ms time window returning the same value. Example: X: 10 , Y: 30 X: 10 , Y: 30 X: 10, Y: 30 .. // After 100 ms X: 300, Y: 300 X: 300, y: 300 .. // After 100 ms X: 1743, Y: 621 X: 1743, Y: 621 For some reason if instead of starting to read at register 0x2 you start reading at register 0x0 this issue isn't seen. This seems like a quirk only seen in the EDT FT5506 so to fix this issue simply adjust the code to start reading from 0x0. Technically this isn't wrong so no regressions should be seen with other touchscreen controllers supported by this driver. Signed-off-by: Franklin S Cooper Jr Signed-off-by: Dmitry Torokhov --- drivers/input/touchscreen/edt-ft5x06.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/input') diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c index 214d8a08a469..0b0f8c17f3f7 100644 --- a/drivers/input/touchscreen/edt-ft5x06.c +++ b/drivers/input/touchscreen/edt-ft5x06.c @@ -172,7 +172,7 @@ static irqreturn_t edt_ft5x06_ts_isr(int irq, void *dev_id) struct edt_ft5x06_ts_data *tsdata = dev_id; struct device *dev = &tsdata->client->dev; u8 cmd; - u8 rdbuf[61]; + u8 rdbuf[63]; int i, type, x, y, id; int offset, tplen, datalen, crclen; int error; @@ -186,8 +186,8 @@ static irqreturn_t edt_ft5x06_ts_isr(int irq, void *dev_id) break; case M09: - cmd = 0x02; - offset = 1; + cmd = 0x0; + offset = 3; tplen = 6; crclen = 0; break; -- cgit v1.2.3