iio: mxs-lradc: only update the buffer when its conversions have finished

commit 89bb35e200bee745c539a96666e0792301ca40f1 upstream.

Using the touchscreen while running buffered capture results in the
buffer reporting lots of wrong values, often just zeros. This is because
we push readings to the buffer every time a touchscreen interrupt
arrives, including when the buffer's own conversions have not yet
finished. So let's only push to the buffer when its conversions are
ready.

Signed-off-by: Kristina Martšenko <kristina.martsenko@gmail.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index 822cced84659a71be7105304bcc0a62d749ee75b..351339ccaad6715b6d6fdcebfe4a38cf5c2830e1 100644 (file)
--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c
@@ -1152,10 +1152,12 @@ static irqreturn_t mxs_lradc_handle_irq(int irq, void *data)
                                LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL2));
        }
 
-       if (iio_buffer_enabled(iio))
-               iio_trigger_poll(iio->trig);
-       else if (reg & LRADC_CTRL1_LRADC_IRQ(0))
+       if (iio_buffer_enabled(iio)) {
+               if (reg & lradc->buffer_vchans)
+                       iio_trigger_poll(iio->trig);
+       } else if (reg & LRADC_CTRL1_LRADC_IRQ(0)) {
                complete(&lradc->completion);
+       }
 
        mxs_lradc_reg_clear(lradc, reg & clr_irq, LRADC_CTRL1);