[PATCH] iio: at91-sama5d2_adc: fix iio_triggered_buffer_{predisable,postenable} positions

[Alexandru Ardelean]

The iio_triggered_buffer_{predisable,postenable} functions attach/detach
poll functions.

The iio_triggered_buffer_postenable() should be called first to attach the
poll function, and then the driver can init the data to be triggered.

Similarly, iio_triggered_buffer_predisable() should be called last to first
disable the data (to be triggered) and then the poll function should be
detached.

For this driver, the predisable & postenable hooks are also need to take
into consideration the touchscreen, so the hooks need to be put in places
that avoid the code for that cares about it.

Signed-off-by: Alexandru Ardelean <alexandru.ardel...@analog.com>
---
 drivers/iio/adc/at91-sama5d2_adc.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c 
b/drivers/iio/adc/at91-sama5d2_adc.c
index e1850f3d5cf3..ac3e5c4c9840 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -889,20 +889,24 @@ static int at91_adc_buffer_postenable(struct iio_dev 
*indio_dev)
        if (!(indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES))
                return -EINVAL;
 
+       ret = iio_triggered_buffer_postenable(indio_dev);
+       if (ret)
+               return ret;
+
        /* we continue with the triggered buffer */
        ret = at91_adc_dma_start(indio_dev);
        if (ret) {
                dev_err(&indio_dev->dev, "buffer postenable failed\n");
+               iio_triggered_buffer_predisable(indio_dev);
                return ret;
        }
 
-       return iio_triggered_buffer_postenable(indio_dev);
+       return 0;
 }
 
 static int at91_adc_buffer_predisable(struct iio_dev *indio_dev)
 {
        struct at91_adc_state *st = iio_priv(indio_dev);
-       int ret;
        u8 bit;
 
        /* check if we are disabling triggered buffer or the touchscreen */
@@ -916,13 +920,8 @@ static int at91_adc_buffer_predisable(struct iio_dev 
*indio_dev)
        if (!(indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES))
                return -EINVAL;
 
-       /* continue with the triggered buffer */
-       ret = iio_triggered_buffer_predisable(indio_dev);
-       if (ret < 0)
-               dev_err(&indio_dev->dev, "buffer predisable failed\n");
-
        if (!st->dma_st.dma_chan)
-               return ret;
+               goto out;
 
        /* if we are using DMA we must clear registers and end DMA */
        dmaengine_terminate_sync(st->dma_st.dma_chan);
@@ -949,7 +948,9 @@ static int at91_adc_buffer_predisable(struct iio_dev 
*indio_dev)
 
        /* read overflow register to clear possible overflow status */
        at91_adc_readl(st, AT91_SAMA5D2_OVER);
-       return ret;
+
+out:
+       return iio_triggered_buffer_predisable(indio_dev);
 }
 
 static const struct iio_buffer_setup_ops at91_buffer_setup_ops = {
-- 
2.20.1