iio: adc: stm32-dfsdm: move dma enable from start_conv() to start_dma()

Move DMA enable (e.g. set RDMAEN bit) away from start_conv() that is used
for both buffer and single conversions. Thus, single conv rely on
interrupt, not dma.
Note: take care to prepare all DMA stuff and set RDMAEN before starting
filter (can be set only when DFEN=0).

This is precursor patch to ease support of triggered buffer mode.

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 8690672..818627f 100644 (file)
--- a/drivers/iio/adc/stm32-dfsdm-adc.c
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -429,12 +429,10 @@ static ssize_t dfsdm_adc_audio_set_spiclk(struct iio_dev *indio_dev,
 }
 
 static int stm32_dfsdm_start_conv(struct stm32_dfsdm_adc *adc,
-                                 const struct iio_chan_spec *chan,
-                                 bool dma)
+                                 const struct iio_chan_spec *chan)
 {
        struct regmap *regmap = adc->dfsdm->regmap;
        int ret;
-       unsigned int dma_en = 0;
 
        ret = stm32_dfsdm_start_channel(adc->dfsdm, chan->channel);
        if (ret < 0)
@@ -444,25 +442,12 @@ static int stm32_dfsdm_start_conv(struct stm32_dfsdm_adc *adc,
        if (ret < 0)
                goto stop_channels;
 
-       if (dma) {
-               /* Enable DMA transfer*/
-               dma_en =  DFSDM_CR1_RDMAEN(1);
-       }
-       /* Enable DMA transfer*/
-       ret = regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
-                                DFSDM_CR1_RDMAEN_MASK, dma_en);
-       if (ret < 0)
-               goto filter_unconfigure;
-
        ret = stm32_dfsdm_start_filter(adc->dfsdm, adc->fl_id);
        if (ret < 0)
-               goto stop_dma;
+               goto filter_unconfigure;
 
        return 0;
 
-stop_dma:
-       regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
-                          DFSDM_CR1_RDMAEN_MASK, 0);
 filter_unconfigure:
        regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
                           DFSDM_CR1_CFG_MASK, 0);
@@ -479,10 +464,6 @@ static void stm32_dfsdm_stop_conv(struct stm32_dfsdm_adc *adc,
 
        stm32_dfsdm_stop_filter(adc->dfsdm, adc->fl_id);
 
-       /* Clean conversion options */
-       regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
-                          DFSDM_CR1_RDMAEN_MASK, 0);
-
        regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
                           DFSDM_CR1_CFG_MASK, 0);
 
@@ -599,15 +580,36 @@ static int stm32_dfsdm_adc_dma_start(struct iio_dev *indio_dev)
 
        cookie = dmaengine_submit(desc);
        ret = dma_submit_error(cookie);
-       if (ret) {
-               dmaengine_terminate_all(adc->dma_chan);
-               return ret;
-       }
+       if (ret)
+               goto err_stop_dma;
 
        /* Issue pending DMA requests */
        dma_async_issue_pending(adc->dma_chan);
 
+       /* Enable DMA transfer*/
+       ret = regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR1(adc->fl_id),
+                                DFSDM_CR1_RDMAEN_MASK, DFSDM_CR1_RDMAEN_MASK);
+       if (ret < 0)
+               goto err_stop_dma;
+
        return 0;
+
+err_stop_dma:
+       dmaengine_terminate_all(adc->dma_chan);
+
+       return ret;
+}
+
+static void stm32_dfsdm_adc_dma_stop(struct iio_dev *indio_dev)
+{
+       struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+
+       if (!adc->dma_chan)
+               return;
+
+       regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR1(adc->fl_id),
+                          DFSDM_CR1_RDMAEN_MASK, 0);
+       dmaengine_terminate_all(adc->dma_chan);
 }
 
 static int stm32_dfsdm_postenable(struct iio_dev *indio_dev)
@@ -623,24 +625,22 @@ static int stm32_dfsdm_postenable(struct iio_dev *indio_dev)
        if (ret < 0)
                return ret;
 
-       ret = stm32_dfsdm_start_conv(adc, chan, true);
+       ret = stm32_dfsdm_adc_dma_start(indio_dev);
        if (ret) {
-               dev_err(&indio_dev->dev, "Can't start conversion\n");
+               dev_err(&indio_dev->dev, "Can't start DMA\n");
                goto stop_dfsdm;
        }
 
-       if (adc->dma_chan) {
-               ret = stm32_dfsdm_adc_dma_start(indio_dev);
-               if (ret) {
-                       dev_err(&indio_dev->dev, "Can't start DMA\n");
-                       goto err_stop_conv;
-               }
+       ret = stm32_dfsdm_start_conv(adc, chan);
+       if (ret) {
+               dev_err(&indio_dev->dev, "Can't start conversion\n");
+               goto err_stop_dma;
        }
 
        return 0;
 
-err_stop_conv:
-       stm32_dfsdm_stop_conv(adc, chan);
+err_stop_dma:
+       stm32_dfsdm_adc_dma_stop(indio_dev);
 stop_dfsdm:
        stm32_dfsdm_stop_dfsdm(adc->dfsdm);
 
@@ -652,11 +652,10 @@ static int stm32_dfsdm_predisable(struct iio_dev *indio_dev)
        struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
        const struct iio_chan_spec *chan = &indio_dev->channels[0];
 
-       if (adc->dma_chan)
-               dmaengine_terminate_all(adc->dma_chan);
-
        stm32_dfsdm_stop_conv(adc, chan);
 
+       stm32_dfsdm_adc_dma_stop(indio_dev);
+
        stm32_dfsdm_stop_dfsdm(adc->dfsdm);
 
        return 0;
@@ -736,7 +735,7 @@ static int stm32_dfsdm_single_conv(struct iio_dev *indio_dev,
        if (ret < 0)
                goto stop_dfsdm;
 
-       ret = stm32_dfsdm_start_conv(adc, chan, false);
+       ret = stm32_dfsdm_start_conv(adc, chan);
        if (ret < 0) {
                regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR2(adc->fl_id),
                                   DFSDM_CR2_REOCIE_MASK, DFSDM_CR2_REOCIE(0));