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authorFabrice Gasnier <fabrice.gasnier@st.com>2018-01-05 15:34:54 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-03 17:39:23 +0100
commite2d4cdb7b8a4b2f8d4dfc2ae067229595ec0190c (patch)
tree12f2a701637c6fb0a520a15cfd1abde706dad462
parentcfd96cbd607ab5d63a33cd63673221f4d572ea8c (diff)
iio: adc: stm32: fix scan of multiple channels with DMA
commit 04e491ca9df60ffe8637d00d68e5ab8bc73b30d5 upstream. By default, watermark is set to '1'. Watermark is used to fine tune cyclic dma buffer period. In case watermark is left untouched (e.g. 1) and several channels are being scanned, buffer period is wrongly set (e.g. to 1 sample). As a consequence, data is never pushed to upper layer. Fix buffer period size, by taking scan channels number into account. Fixes: 2763ea0585c9 ("iio: adc: stm32: add optional dma support") Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/iio/adc/stm32-adc.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 4df32cf1650e..172753b14a4f 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -1314,6 +1314,7 @@ static int stm32_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
{
struct stm32_adc *adc = iio_priv(indio_dev);
unsigned int watermark = STM32_DMA_BUFFER_SIZE / 2;
+ unsigned int rx_buf_sz = STM32_DMA_BUFFER_SIZE;
/*
* dma cyclic transfers are used, buffer is split into two periods.
@@ -1322,7 +1323,7 @@ static int stm32_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
* - one buffer (period) driver can push with iio_trigger_poll().
*/
watermark = min(watermark, val * (unsigned)(sizeof(u16)));
- adc->rx_buf_sz = watermark * 2;
+ adc->rx_buf_sz = min(rx_buf_sz, watermark * 2 * adc->num_conv);
return 0;
}