[PATCH v2 7/8] spi: imx: defer spi initialization, if DMA engine is pending

From: Anton Bondarenko
Date: Fri Sep 25 2015 - 13:59:43 EST


If SPI device supports DMA mode, but DMA controller is not yet
available due to e.g. a delay in the corresponding kernel module
initialization, retry to initialize SPI driver later on instead of
falling back into PIO only mode.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@xxxxxxxxxx>
Signed-off-by: Anton Bondarenko <anton_bondarenko@xxxxxxxxxx>
---
drivers/spi/spi-imx.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 44d3cf0..1bf0739a 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -1343,9 +1343,15 @@ static int spi_imx_probe(struct platform_device *pdev)
* Only validated on i.mx6 now, can remove the constrain if validated on
* other chips.
*/
- if (is_imx5x_ecspi(spi_imx) &&
- spi_imx_sdma_init(&pdev->dev, spi_imx, master))
- dev_err(&pdev->dev, "dma setup error,use pio instead\n");
+ if (is_imx5x_ecspi(spi_imx)) {
+ ret = spi_imx_sdma_init(&pdev->dev, spi_imx, master);
+ if (ret == -EPROBE_DEFER)
+ goto out_clk_put;
+
+ if (ret < 0)
+ dev_err(&pdev->dev, "dma setup error %d, use pio\n",
+ ret);
+ }

spi_imx->devtype_data->reset(spi_imx);

--
2.5.2

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