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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Fabrice Gasnier <fabrice.gasnier@st.com>,
        Stable@vger.kernel.org,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 76/81] iio: adc: stm32-adc: fix device used to request dma
Date:   Tue, 26 May 2020 20:53:51 +0200
Message-Id: <20200526183935.502017260@linuxfoundation.org>
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From: Fabrice Gasnier <fabrice.gasnier@st.com>

[ 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@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 d85caedda02e..59fd8b620c50 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -1682,18 +1682,18 @@ 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;
@@ -1816,7 +1816,7 @@ static int stm32_adc_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto err_clk_disable;
 
-	ret = stm32_adc_dma_request(indio_dev);
+	ret = stm32_adc_dma_request(dev, indio_dev);
 	if (ret < 0)
 		goto err_clk_disable;
 
-- 
2.25.1