Hi Alexandre,

quoted

While I don't have much experience with the TS part of the code but I
can investigate if you don't have any idea.

can you please test the following patch?
After releasing the touchscreen the internal state machine was left in a
wrong state.

diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index e2dd783..558a76c 100644
--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c

@@ -698,6 +698,7 @@ static void mxs_lradc_finish_touch_event(struct mxs_lradc *lradc, bool valid)
        }

        /* if it is released, wait for the next touch via IRQ */
+       lradc->cur_plate = LRADC_TOUCH;
        mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ, LRADC_CTRL1);
        mxs_lradc_reg_set(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
 }