linux-kernel - [PATCH] i2c: stm32: do not display error when DMA is not requested

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Date:   Thu, 10 Sep 2020 11:32:29 +0200
From:   Alain Volmat <alain.volmat@...com>
To:     <wsa@...nel.org>, <pierre-yves.mordret@...com>
CC:     <alexandre.torgue@...com>, <linux-i2c@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <fabrice.gasnier@...com>,
        <alain.volmat@...com>
Subject: [PATCH] i2c: stm32: do not display error when DMA is not requested

DMA usage is optional for the I2C driver. check for the -ENODEV
error in order to avoid displaying an error when no DMA
has been requested.

Signed-off-by: Alain Volmat <alain.volmat@...com>
---
This patch should be applied on top of the patch [i2c: stm32: Simplify with dev_err_probe()]
---
 drivers/i2c/busses/i2c-stm32.c   | 16 ++++++++++------
 drivers/i2c/busses/i2c-stm32f7.c |  5 +++++
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-stm32.c b/drivers/i2c/busses/i2c-stm32.c
index 198f848b7be9..91767156d63d 100644
--- a/drivers/i2c/busses/i2c-stm32.c
+++ b/drivers/i2c/busses/i2c-stm32.c
@@ -25,8 +25,11 @@ struct stm32_i2c_dma *stm32_i2c_dma_request(struct device *dev,
 	/* Request and configure I2C TX dma channel */
 	dma->chan_tx = dma_request_chan(dev, "tx");
 	if (IS_ERR(dma->chan_tx)) {
-		ret = dev_err_probe(dev, PTR_ERR(dma->chan_tx),
-				    "can't request DMA tx channel\n");
+		if (PTR_ERR(dma->chan_tx) == -ENODEV)
+			ret = PTR_ERR(dma->chan_tx);
+		else
+			ret = dev_err_probe(dev, PTR_ERR(dma->chan_tx),
+					    "can't request DMA tx channel\n");
 		goto fail_al;
 	}
 
@@ -44,8 +47,11 @@ struct stm32_i2c_dma *stm32_i2c_dma_request(struct device *dev,
 	/* Request and configure I2C RX dma channel */
 	dma->chan_rx = dma_request_chan(dev, "rx");
 	if (IS_ERR(dma->chan_rx)) {
-		ret = dev_err_probe(dev, PTR_ERR(dma->chan_rx),
-				    "can't request DMA rx channel\n");
+		if (PTR_ERR(dma->chan_tx) == -ENODEV)
+			ret = PTR_ERR(dma->chan_tx);
+		else
+			ret = dev_err_probe(dev, PTR_ERR(dma->chan_rx),
+					    "can't request DMA rx channel\n");
 		goto fail_tx;
 	}
 
@@ -73,8 +79,6 @@ struct stm32_i2c_dma *stm32_i2c_dma_request(struct device *dev,
 	dma_release_channel(dma->chan_tx);
 fail_al:
 	devm_kfree(dev, dma);
-	if (ret != -EPROBE_DEFER)
-		dev_info(dev, "can't use DMA\n");
 
 	return ERR_PTR(ret);
 }
diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index a8f1758e4c5b..58f342aea3c1 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -2049,6 +2049,11 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
 					     STM32F7_I2C_TXDR,
 					     STM32F7_I2C_RXDR);
 	if (PTR_ERR(i2c_dev->dma) == -ENODEV) {
+		/*
+		 * DMA usage is not mandatory for the I2C, it is not an error
+		 * to receive -ENODEV
+		 */
+		dev_dbg(i2c_dev->dev, "not using DMA\n");
 		i2c_dev->dma = NULL;
 	} else if (IS_ERR(i2c_dev->dma)) {
 		ret = dev_err_probe(&pdev->dev, PTR_ERR(i2c_dev->dma),
-- 
2.7.4