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iio: adc: at91-sama5d2_adc: fix DMA conversion crash

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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: f3c034f617 ("iio: at91-sama5d2_adc: adjust iio_triggered_buffer_{predisable,postenable} positions")
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Link: https://lore.kernel.org/r/20200923121748.49384-1-eugen.hristev@microchip.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Eugen Hristev 2020-09-23 15:17:48 +03:00 committed by Jonathan Cameron
parent b8a533f3c2
commit 1a19879445
1 changed files with 12 additions and 4 deletions
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16
drivers/iio/adc/at91-sama5d2_adc.c
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@ -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,
};
@ -1563,6 +1562,7 @@ static void at91_adc_dma_disable(struct platform_device *pdev)
static int at91_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
{
struct at91_adc_state *st = iio_priv(indio_dev);
int ret;
if (val > AT91_HWFIFO_MAX_SIZE)
return -EINVAL;
@ -1586,7 +1586,15 @@ 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
*/
ret = at91_adc_buffer_prepare(indio_dev);
if (ret)
at91_adc_dma_disable(to_platform_device(&indio_dev->dev));
return ret;
}
static int at91_adc_update_scan_mode(struct iio_dev *indio_dev,