iio: adc: stm32-dfsdm: move dma slave config to start routine

Move DMA slave configuration to start routine: depending on regular or
injected mode is in use, DMA needs to read resp. RDATAR or JDATAR.
This is precursor patch to introduce injected mode (used for scan).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
index 818627f..66e2ea0 100644 (file)
--- a/drivers/iio/adc/stm32-dfsdm-adc.c
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -556,6 +556,11 @@ static void stm32_dfsdm_audio_dma_buffer_done(void *data)
 static int stm32_dfsdm_adc_dma_start(struct iio_dev *indio_dev)
 {
        struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+       struct dma_slave_config config = {
+               .src_addr = (dma_addr_t)adc->dfsdm->phys_base +
+                       DFSDM_RDATAR(adc->fl_id),
+               .src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
+       };
        struct dma_async_tx_descriptor *desc;
        dma_cookie_t cookie;
        int ret;
@@ -566,6 +571,10 @@ static int stm32_dfsdm_adc_dma_start(struct iio_dev *indio_dev)
        dev_dbg(&indio_dev->dev, "%s size=%d watermark=%d\n", __func__,
                adc->buf_sz, adc->buf_sz / 2);
 
+       ret = dmaengine_slave_config(adc->dma_chan, &config);
+       if (ret)
+               return ret;
+
        /* Prepare a DMA cyclic transaction */
        desc = dmaengine_prep_dma_cyclic(adc->dma_chan,
                                         adc->dma_buf,
@@ -925,12 +934,6 @@ static void stm32_dfsdm_dma_release(struct iio_dev *indio_dev)
 static int stm32_dfsdm_dma_request(struct iio_dev *indio_dev)
 {
        struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
-       struct dma_slave_config config = {
-               .src_addr = (dma_addr_t)adc->dfsdm->phys_base +
-                       DFSDM_RDATAR(adc->fl_id),
-               .src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
-       };
-       int ret;
 
        adc->dma_chan = dma_request_slave_channel(&indio_dev->dev, "rx");
        if (!adc->dma_chan)
@@ -940,23 +943,11 @@ static int stm32_dfsdm_dma_request(struct iio_dev *indio_dev)
                                         DFSDM_DMA_BUFFER_SIZE,
                                         &adc->dma_buf, GFP_KERNEL);
        if (!adc->rx_buf) {
-               ret = -ENOMEM;
-               goto err_release;
+               dma_release_channel(adc->dma_chan);
+               return -ENOMEM;
        }
 
-       ret = dmaengine_slave_config(adc->dma_chan, &config);
-       if (ret)
-               goto err_free;
-
        return 0;
-
-err_free:
-       dma_free_coherent(adc->dma_chan->device->dev, DFSDM_DMA_BUFFER_SIZE,
-                         adc->rx_buf, adc->dma_buf);
-err_release:
-       dma_release_channel(adc->dma_chan);
-
-       return ret;
 }
 
 static int stm32_dfsdm_adc_chan_init_one(struct iio_dev *indio_dev,