[PATCH 5.4 103/111] iio: adc: stm32-adc: fix device used to request dma

From: Greg Kroah-Hartman
Date: Tue May 26 2020 - 15:10:27 EST

From: Fabrice Gasnier <fabrice.gasnier@xxxxxx>

[ Upstream commit 52cd91c27f3908b88e8b25aed4a4d20660abcc45 ]

DMA channel request should use device struct from platform device struct.
Currently it's using iio device struct. But at this stage when probing,
device struct isn't yet registered (e.g. device_register is done in
iio_device_register). Since commit 71723a96b8b1 ("dmaengine: Create
symlinks between DMA channels and slaves"), a warning message is printed
as the links in sysfs can't be created, due to device isn't yet registered:
- Cannot create DMA slave symlink
- Cannot create DMA dma:rx symlink

Fix this by using device struct from platform device to request dma chan.

Fixes: 2763ea0585c99 ("iio: adc: stm32: add optional dma support")

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
Cc: <Stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/iio/adc/stm32-adc.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index a2279cccb584..94fde39d9ff7 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -1757,18 +1757,18 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev)
return 0;

-static int stm32_adc_dma_request(struct iio_dev *indio_dev)
+static int stm32_adc_dma_request(struct device *dev, struct iio_dev *indio_dev)
struct stm32_adc *adc = iio_priv(indio_dev);
struct dma_slave_config config;
int ret;

- adc->dma_chan = dma_request_chan(&indio_dev->dev, "rx");
+ adc->dma_chan = dma_request_chan(dev, "rx");
if (IS_ERR(adc->dma_chan)) {
ret = PTR_ERR(adc->dma_chan);
if (ret != -ENODEV) {
if (ret != -EPROBE_DEFER)
- dev_err(&indio_dev->dev,
+ dev_err(dev,
"DMA channel request failed with %d\n",
return ret;
@@ -1874,7 +1874,7 @@ static int stm32_adc_probe(struct platform_device *pdev)
if (ret < 0)
return ret;

- ret = stm32_adc_dma_request(indio_dev);
+ ret = stm32_adc_dma_request(dev, indio_dev);
if (ret < 0)
return ret;