The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 52cd91c27f3908b88e8b25aed4a4d20660abcc45 Mon Sep 17 00:00:00 2001

From: Fabrice Gasnier fabrice.gasnier@st.com Date: Thu, 30 Apr 2020 11:28:45 +0200 Subject: [PATCH] iio: adc: stm32-adc: fix device used to request dma

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@st.com Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index ae622ee6d08c..dfc3a306c667 100644 --- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c @@ -1812,18 +1812,18 @@ 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", ret); return ret; @@ -1930,7 +1930,7 @@ 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;