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From:   Wadim Egorov <w.egorov@phytec.de>
To:     <jic23@kernel.org>, <lars@metafoo.de>, <robh@kernel.org>,
        <heiko@sntech.de>, <peter.ujfalusi@ti.com>, <mugunthanvnm@ti.com>
CC:     <linux-iio@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <nm@ti.com>, <upstream@lists.phytec.de>
Subject: [PATCH v2] iio: adc: ti_am335x_adc: Fix return value check of tiadc_request_dma()
Date:   Mon, 25 Sep 2023 15:44:27 +0200
Message-ID: <20230925134427.214556-1-w.egorov@phytec.de>
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Fix wrong handling of a DMA request where the probing only failed
if -EPROPE_DEFER was returned. Instead, let us fail if a non -ENODEV
value is returned. This makes DMAs explicitly optional. Even if the
DMA request is unsuccessfully, the ADC can still work properly.
We do also handle the defer probe case by making use of dev_err_probe().

Fixes: f438b9da75eb ("drivers: iio: ti_am335x_adc: add dma support")
Signed-off-by: Wadim Egorov <w.egorov@phytec.de>
---
v2:
  - Update description
  - Drop line break after Fixes tag
  - Move decision about optional DMA into probe/caller
---
 drivers/iio/adc/ti_am335x_adc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index 8db7a01cb5fb..5f8795986995 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c
@@ -670,8 +670,10 @@ 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 && err != -ENODEV) {
+		dev_err_probe(&pdev->dev, err, "DMA request failed\n");
 		goto err_dma;
+	}
 
 	return 0;
 
-- 
2.34.1