linux-kernel - [PATCH v2 1/4] spi: stm32: properly fail on dma_request

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Message-ID: <20251218-stm32-spi-enhancements-v2-1-3b69901ca9fe@foss.st.com>
Date: Thu, 18 Dec 2025 11:48:27 +0100
From: Alain Volmat <alain.volmat@...s.st.com>
To: Mark Brown <broonie@...nel.org>,
        Maxime Coquelin
	<mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>
CC: <linux-spi@...r.kernel.org>, <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <devicetree@...r.kernel.org>, Alain Volmat <alain.volmat@...s.st.com>
Subject: [PATCH v2 1/4] spi: stm32: properly fail on dma_request_chan error

Correct handling of the dma_request_chan call in order to avoid
misleading warn message if no DMA is provided within the device-tree
and moreover fail if dma_request_chan has returned a valid error.

Signed-off-by: Alain Volmat <alain.volmat@...s.st.com>
---
 drivers/spi/spi-stm32.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 2c804c1aef98..40651b6050f6 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -2406,11 +2406,13 @@ static int stm32_spi_probe(struct platform_device *pdev)
 	spi->dma_tx = dma_request_chan(spi->dev, "tx");
 	if (IS_ERR(spi->dma_tx)) {
 		ret = PTR_ERR(spi->dma_tx);
-		spi->dma_tx = NULL;
-		if (ret == -EPROBE_DEFER)
+		if (ret == -ENODEV) {
+			dev_info(&pdev->dev, "tx dma disabled\n");
+			spi->dma_tx = NULL;
+		} else {
+			dev_err_probe(&pdev->dev, ret, "failed to request tx dma channel\n");
 			goto err_clk_disable;
-
-		dev_warn(&pdev->dev, "failed to request tx dma channel\n");
+		}
 	} else {
 		ctrl->dma_tx = spi->dma_tx;
 	}
@@ -2418,11 +2420,13 @@ static int stm32_spi_probe(struct platform_device *pdev)
 	spi->dma_rx = dma_request_chan(spi->dev, "rx");
 	if (IS_ERR(spi->dma_rx)) {
 		ret = PTR_ERR(spi->dma_rx);
-		spi->dma_rx = NULL;
-		if (ret == -EPROBE_DEFER)
+		if (ret == -ENODEV) {
+			dev_info(&pdev->dev, "rx dma disabled\n");
+			spi->dma_rx = NULL;
+		} else {
+			dev_err_probe(&pdev->dev, ret, "failed to request rx dma channel\n");
 			goto err_dma_release;
-
-		dev_warn(&pdev->dev, "failed to request rx dma channel\n");
+		}
 	} else {
 		ctrl->dma_rx = spi->dma_rx;
 	}

-- 
2.34.1