[PATCH v2 4/8] iio: adc: stm32-dfsdm: move dma slave config to start routine

Fabrice Gasnier
2019-03-21T16:48:01Z

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>
---
drivers/iio/adc/stm32-dfsdm-adc.c | 31 +++++++++++--------------------
1 file changed, 11 insertions(+), 20 deletions(-)

diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
index 818627f..66e2ea0 100644
--- 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,
--
2.7.4