Re: BBB touch screen and ADC interactions

[Michael Welling <mwelling@ieee.org>]

On Tue, May 19, 2015 at 05:16:46PM -0700, Greg Wilson-Lindberg wrote:
> 
> I would be happy to test the patch, better than what I was going to try.
> 
> -Greg

Below is the simple workaround patch that I used to eliminate the repeated
release events that were occurring without touching the screen.

See if it helps.

diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
index 191a1b8..f876097 100644
--- a/drivers/input/touchscreen/ti_am335x_tsc.c
+++ b/drivers/input/touchscreen/ti_am335x_tsc.c
@@ -281,13 +281,11 @@ static irqreturn_t titsc_irq(int irq, void *dev)
 	if (status & IRQENB_PENUP) {
 		fsm = titsc_readl(ts_dev, REG_ADCFSM);
 		if (fsm == ADCFSM_STEPID) {
-			ts_dev->pen_down = false;
 			input_report_key(input_dev, BTN_TOUCH, 0);
 			input_report_abs(input_dev, ABS_PRESSURE, 0);
 			input_sync(input_dev);
-		} else {
-			ts_dev->pen_down = true;
 		}
+		ts_dev->pen_down = false;
 		irqclr |= IRQENB_PENUP;
 	}