[PATCH] iio: adc: ti_am335x_adc: Make DMAs optional

[Wadim Egorov <w.egorov@phytec.de>]

DMAs are optional. Even if the DMA request is unsuccessfully,
the ADC can still work properly.
Make tiadc_request_dma() not fail if we do not provide dmas &
dma-names properties.

This actually fixes the wrong error handling of the tiadc_request_dma()
result where the probing only failed if -EPROPE_DEFER was returned.

Fixes: f438b9da75eb ("drivers: iio: ti_am335x_adc: add dma support")

Signed-off-by: Wadim Egorov <w.egorov@phytec.de>
---
 drivers/iio/adc/ti_am335x_adc.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index 8db7a01cb5fb..e14aa9254ab1 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c
@@ -543,8 +543,11 @@ static int tiadc_request_dma(struct platform_device *pdev,
 	if (IS_ERR(dma->chan)) {
 		int ret = PTR_ERR(dma->chan);
 
+		if (ret != -ENODEV)
+			return dev_err_probe(&pdev->dev, ret,
+					     "RX DMA channel request failed\n");
 		dma->chan = NULL;
-		return ret;
+		return 0;
 	}
 
 	/* RX buffer */
@@ -670,7 +673,7 @@ static int tiadc_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, indio_dev);
 
 	err = tiadc_request_dma(pdev, adc_dev);
-	if (err && err == -EPROBE_DEFER)
+	if (err)
 		goto err_dma;
 
 	return 0;
-- 
2.25.1