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

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>
Cc: Stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index d2e0c275bf4d09383ee59bb3eba1b26155147c1e..ebcbd12d48b9c10767c692621fffcffad87798b5 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);