diff mbox series

[v2,05/19] iio: adc: at91-sama5d2_adc: exit from write_raw() when buffers are enabled

Message ID 20220628151631.3116454-6-claudiu.beznea@microchip.com (mailing list archive)
State Accepted
Headers show
Series iio: adc: at91-sama5d2_adc: add support for temperature sensor | expand

Commit Message

Claudiu Beznea June 28, 2022, 3:16 p.m. UTC
When buffers are enabled conversion may start asynchronously thus
allowing changes on actual hardware could lead to bad behavior. Thus
do not allow changing oversampling ratio and sample frequency when
if iio_device_claim_direct_mode() returns with error.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 drivers/iio/adc/at91-sama5d2_adc.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
diff mbox series

Patch

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index 2c087d52f164..cd2b8190a8da 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -1641,6 +1641,7 @@  static int at91_adc_write_raw(struct iio_dev *indio_dev,
 			      int val, int val2, long mask)
 {
 	struct at91_adc_state *st = iio_priv(indio_dev);
+	int ret;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
@@ -1650,20 +1651,29 @@  static int at91_adc_write_raw(struct iio_dev *indio_dev,
 		/* if no change, optimize out */
 		if (val == st->oversampling_ratio)
 			return 0;
+
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
 		mutex_lock(&st->lock);
 		st->oversampling_ratio = val;
 		/* update ratio */
 		at91_adc_config_emr(st);
 		mutex_unlock(&st->lock);
+		iio_device_release_direct_mode(indio_dev);
 		return 0;
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		if (val < st->soc_info.min_sample_rate ||
 		    val > st->soc_info.max_sample_rate)
 			return -EINVAL;
 
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
 		mutex_lock(&st->lock);
 		at91_adc_setup_samp_freq(indio_dev, val);
 		mutex_unlock(&st->lock);
+		iio_device_release_direct_mode(indio_dev);
 		return 0;
 	default:
 		return -EINVAL;