After the move of the postenable code to preenable, the DMA start was
done before the DMA init, which is not correct.
The DMA is initialized in set_watermark. Because of this, we need to call
the DMA start functions in set_watermark, after the DMA init, instead of
preenable hook, when the DMA is not properly setup yet.
Fixes: f3c034f61775 ("iio: at91-sama5d2_adc: adjust iio_triggered_buffer_{predisable,postenable} positions")
Signed-off-by: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx>
---
Hi,
This crash is in the kernel since 5.8-rc1
Please have a look at discussion here:
https://lore.kernel.org/linux-iio/CA+U=DsqRUtjjoe5nevP_wNxTgr27+O2V1h9w7d3QijBQ+5f3XA@xxxxxxxxxxxxxx/T/#t
Thanks !
drivers/iio/adc/at91-sama5d2_adc.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index de9583d6cddd..b5196797dcb8 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -884,7 +884,7 @@ static bool at91_adc_current_chan_is_touch(struct iio_dev *indio_dev)
AT91_SAMA5D2_MAX_CHAN_IDX + 1);
}
-static int at91_adc_buffer_preenable(struct iio_dev *indio_dev)
+static int at91_adc_buffer_prepare(struct iio_dev *indio_dev)
{
int ret;
u8 bit;
@@ -901,7 +901,7 @@ static int at91_adc_buffer_preenable(struct iio_dev *indio_dev)
/* we continue with the triggered buffer */
ret = at91_adc_dma_start(indio_dev);
if (ret) {
- dev_err(&indio_dev->dev, "buffer postenable failed\n");
+ dev_err(&indio_dev->dev, "buffer prepare failed\n");
return ret;
}
@@ -989,7 +989,6 @@ static int at91_adc_buffer_postdisable(struct iio_dev *indio_dev)
}
static const struct iio_buffer_setup_ops at91_buffer_setup_ops = {
- .preenable = &at91_adc_buffer_preenable,
.postdisable = &at91_adc_buffer_postdisable,
};
@@ -1586,7 +1585,11 @@ static int at91_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
else if (val > 1)
at91_adc_dma_init(to_platform_device(&indio_dev->dev));
- return 0;
+ /*
+ * We can start the DMA only after setting the watermark and
+ * having the DMA initialization completed
+ */
+ return at91_adc_buffer_prepare(indio_dev);
}
static int at91_adc_update_scan_mode(struct iio_dev *indio_dev,
--
2.25.1
