iio: adc: stm32-adc: dma transfers cleanup

- Remove processing related to DMA in irq handler as this
data transfer is managed directly in DMA callback.
- Update comment in stm32_adc_set_watermark() function.

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Link: https://lore.kernel.org/r/20201105142941.27301-1-olivier.moysan@st.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index b3f31f1..08be826 100644 (file)
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -1310,7 +1310,7 @@ static int stm32_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
         * dma cyclic transfers are used, buffer is split into two periods.
         * There should be :
         * - always one buffer (period) dma is working on
-        * - one buffer (period) driver can push with iio_trigger_poll().
+        * - one buffer (period) driver can push data.
         */
        watermark = min(watermark, val * (unsigned)(sizeof(u16)));
        adc->rx_buf_sz = min(rx_buf_sz, watermark * 2 * adc->num_conv);
@@ -1573,31 +1573,14 @@ static irqreturn_t stm32_adc_trigger_handler(int irq, void *p)
 
        dev_dbg(&indio_dev->dev, "%s bufi=%d\n", __func__, adc->bufi);
 
-       if (!adc->dma_chan) {
-               /* reset buffer index */
-               adc->bufi = 0;
-               iio_push_to_buffers_with_timestamp(indio_dev, adc->buffer,
-                                                  pf->timestamp);
-       } else {
-               int residue = stm32_adc_dma_residue(adc);
-
-               while (residue >= indio_dev->scan_bytes) {
-                       u16 *buffer = (u16 *)&adc->rx_buf[adc->bufi];
-
-                       iio_push_to_buffers_with_timestamp(indio_dev, buffer,
-                                                          pf->timestamp);
-                       residue -= indio_dev->scan_bytes;
-                       adc->bufi += indio_dev->scan_bytes;
-                       if (adc->bufi >= adc->rx_buf_sz)
-                               adc->bufi = 0;
-               }
-       }
-
+       /* reset buffer index */
+       adc->bufi = 0;
+       iio_push_to_buffers_with_timestamp(indio_dev, adc->buffer,
+                                          pf->timestamp);
        iio_trigger_notify_done(indio_dev->trig);
 
        /* re-enable eoc irq */
-       if (!adc->dma_chan)
-               stm32_adc_conv_irq_enable(adc);
+       stm32_adc_conv_irq_enable(adc);
 
        return IRQ_HANDLED;
 }