Commit 907b2ad8 authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Jonathan Cameron
Browse files

iio: at91-sama5d2: Fix incorrect cast to platform_device 



The at91-sama5d2 driver calls `to_platform_device()` on a struct device
that is part of a IIO device. This is incorrect since
`to_platform_device()` must only be called on a struct device that is part
of a platform device.

The code still works by accident because non of the struct platform_device
specific fields are accessed.

Refactor the code a bit so that it behaves identically, but does not use
the incorrect cast. This avoids accidentally adding undefined behavior in
the future by assuming the `struct platform_device` is actually valid.

Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Tested-by: default avatarEugen Hristev <eugen.hristev@microchip.com>
Link: https://lore.kernel.org/r/20211019082929.30503-1-lars@metafoo.de


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent eb046989

drivers/iio/adc/at91-sama5d2_adc.c

+16 −18
Original line number Diff line number Diff line
@@ -1661,10 +1661,9 @@ static int at91_adc_write_raw(struct iio_dev *indio_dev, 
	}

}



static void at91_adc_dma_init(struct platform_device *pdev)

static void at91_adc_dma_init(struct at91_adc_state *st)

{

	struct iio_dev *indio_dev = platform_get_drvdata(pdev);

	struct at91_adc_state *st = iio_priv(indio_dev);

	struct device *dev = &st->indio_dev->dev;

	struct dma_slave_config config = {0};

	/* we have 2 bytes for each channel */

	unsigned int sample_size = st->soc_info.platform->nr_channels * 2;
@@ -1679,9 +1678,9 @@ static void at91_adc_dma_init(struct platform_device *pdev) 
	if (st->dma_st.dma_chan)

		return;



	st->dma_st.dma_chan = dma_request_chan(&pdev->dev, "rx");

	st->dma_st.dma_chan = dma_request_chan(dev, "rx");

	if (IS_ERR(st->dma_st.dma_chan))  {

		dev_info(&pdev->dev, "can't get DMA channel\n");

		dev_info(dev, "can't get DMA channel\n");

		st->dma_st.dma_chan = NULL;

		goto dma_exit;

	}
@@ -1691,7 +1690,7 @@ static void at91_adc_dma_init(struct platform_device *pdev) 
					       &st->dma_st.rx_dma_buf,

					       GFP_KERNEL);

	if (!st->dma_st.rx_buf) {

		dev_info(&pdev->dev, "can't allocate coherent DMA area\n");

		dev_info(dev, "can't allocate coherent DMA area\n");

		goto dma_chan_disable;

	}
@@ -1704,11 +1703,11 @@ static void at91_adc_dma_init(struct platform_device *pdev) 
	config.dst_maxburst = 1;



	if (dmaengine_slave_config(st->dma_st.dma_chan, &config)) {

		dev_info(&pdev->dev, "can't configure DMA slave\n");

		dev_info(dev, "can't configure DMA slave\n");

		goto dma_free_area;

	}



	dev_info(&pdev->dev, "using %s for rx DMA transfers\n",

	dev_info(dev, "using %s for rx DMA transfers\n",

		 dma_chan_name(st->dma_st.dma_chan));



	return;
@@ -1720,13 +1719,12 @@ static void at91_adc_dma_init(struct platform_device *pdev) 
	dma_release_channel(st->dma_st.dma_chan);

	st->dma_st.dma_chan = NULL;

dma_exit:

	dev_info(&pdev->dev, "continuing without DMA support\n");

	dev_info(dev, "continuing without DMA support\n");

}



static void at91_adc_dma_disable(struct platform_device *pdev)

static void at91_adc_dma_disable(struct at91_adc_state *st)

{

	struct iio_dev *indio_dev = platform_get_drvdata(pdev);

	struct at91_adc_state *st = iio_priv(indio_dev);

	struct device *dev = &st->indio_dev->dev;

	/* we have 2 bytes for each channel */

	unsigned int sample_size = st->soc_info.platform->nr_channels * 2;

	unsigned int pages = DIV_ROUND_UP(AT91_HWFIFO_MAX_SIZE *
@@ -1744,7 +1742,7 @@ static void at91_adc_dma_disable(struct platform_device *pdev) 
	dma_release_channel(st->dma_st.dma_chan);

	st->dma_st.dma_chan = NULL;



	dev_info(&pdev->dev, "continuing without DMA support\n");

	dev_info(dev, "continuing without DMA support\n");

}



static int at91_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
@@ -1770,9 +1768,9 @@ static int at91_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val) 
	 */



	if (val == 1)

		at91_adc_dma_disable(to_platform_device(&indio_dev->dev));

		at91_adc_dma_disable(st);

	else if (val > 1)

		at91_adc_dma_init(to_platform_device(&indio_dev->dev));

		at91_adc_dma_init(st);



	/*

	 * We can start the DMA only after setting the watermark and
@@ -1780,7 +1778,7 @@ static int at91_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val) 
	 */

	ret = at91_adc_buffer_prepare(indio_dev);

	if (ret)

		at91_adc_dma_disable(to_platform_device(&indio_dev->dev));

		at91_adc_dma_disable(st);



	return ret;

}
@@ -2077,7 +2075,7 @@ static int at91_adc_probe(struct platform_device *pdev) 
	return 0;



dma_disable:

	at91_adc_dma_disable(pdev);

	at91_adc_dma_disable(st);

per_clk_disable_unprepare:

	clk_disable_unprepare(st->per_clk);

vref_disable:
@@ -2094,7 +2092,7 @@ static int at91_adc_remove(struct platform_device *pdev) 


	iio_device_unregister(indio_dev);



	at91_adc_dma_disable(pdev);

	at91_adc_dma_disable(st);



	clk_disable_unprepare(st->per_clk);