[PATCH v2 3/8] iio: adc: stm32-dfsdm: move dma enable from start_conv() to start_dma()

Fabrice Gasnier
2019-03-21T16:48:42Z

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>
---
drivers/iio/adc/stm32-dfsdm-adc.c | 77 +++++++++++++++++++--------------------
1 file changed, 38 insertions(+), 39 deletions(-)

diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
index 8690672..818627f 100644
--- 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));
--
2.7.4