From: Franklin S Cooper Jr <fcooper@xxxxxx> 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 <fcooper@xxxxxx> --- drivers/input/touchscreen/edt-ft5x06.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c index 752da69..b3ed631 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[59]; + u8 rdbuf[61]; int i, type, x, y, id; int offset, tplen, datalen; int error; @@ -188,8 +188,8 @@ 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; datalen = tplen * tsdata->max_support_points - cmd + 1; break; -- 2.6.1 -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
