[PATCH v2 8/8] iio: adc: stm32-dfsdm: claim direct mode for raw read and settings

Fabrice Gasnier
2019-03-21T16:48:15Z

Claim direct mode to ensure no buffer mode is in use for:
- single conversion
- sample rate setting (must be set when filter isn't enabled).
- oversampling ratio (must be set when filter isn't enabled).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
drivers/iio/adc/stm32-dfsdm-adc.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
index 51688eb..ca42946 100644
--- a/drivers/iio/adc/stm32-dfsdm-adc.c
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -1039,16 +1039,23 @@ static int stm32_dfsdm_write_raw(struct iio_dev *indio_dev,

switch (mask) {
case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+ ret = iio_device_claim_direct_mode(indio_dev);
+ if (ret)
+ return ret;
ret = stm32_dfsdm_set_osrs(fl, 0, val);
if (!ret)
adc->oversamp = val;
-
+ iio_device_release_direct_mode(indio_dev);
return ret;

case IIO_CHAN_INFO_SAMP_FREQ:
if (!val)
return -EINVAL;

+ ret = iio_device_claim_direct_mode(indio_dev);
+ if (ret)
+ return ret;
+
switch (ch->src) {
case DFSDM_CHANNEL_SPI_CLOCK_INTERNAL:
spi_freq = adc->dfsdm->spi_master_freq;
@@ -1070,9 +1077,11 @@ static int stm32_dfsdm_write_raw(struct iio_dev *indio_dev,
if (ret < 0) {
dev_err(&indio_dev->dev,
"Not able to find parameter that match!\n");
+ iio_device_release_direct_mode(indio_dev);
return ret;
}
adc->sample_freq = val;
+ iio_device_release_direct_mode(indio_dev);

return 0;
}
@@ -1089,11 +1098,15 @@ static int stm32_dfsdm_read_raw(struct iio_dev *indio_dev,

switch (mask) {
case IIO_CHAN_INFO_RAW:
+ ret = iio_device_claim_direct_mode(indio_dev);
+ if (ret)
+ return ret;
ret = iio_hw_consumer_enable(adc->hwc);
if (ret < 0) {
dev_err(&indio_dev->dev,
"%s: IIO enable failed (channel %d)\n",
__func__, chan->channel);
+ iio_device_release_direct_mode(indio_dev);
return ret;
}
ret = stm32_dfsdm_single_conv(indio_dev, chan, val);
@@ -1102,8 +1115,10 @@ static int stm32_dfsdm_read_raw(struct iio_dev *indio_dev,
dev_err(&indio_dev->dev,
"%s: Conversion failed (channel %d)\n",
__func__, chan->channel);
+ iio_device_release_direct_mode(indio_dev);
return ret;
}
+ iio_device_release_direct_mode(indio_dev);
return IIO_VAL_INT;

case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
--
2.7.4