i2c: stm32: fix error message on upon dma_request_chan & defer handling

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.
Cleaning up the error messages during probe, remove the additional
-EPROBE_DEFER within probe function since additional error message
doesn't give much more information than what is already reported
within the stm32_i2c_dma_request function.

Signed-off-by: Alain Volmat <alain.volmat@st.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drivers/i2c/busses/i2c-stm32.c

@@ -26,7 +26,7 @@ struct stm32_i2c_dma *stm32_i2c_dma_request(struct device *dev,
 	dma->chan_tx = dma_request_chan(dev, "tx");
 	if (IS_ERR(dma->chan_tx)) {
 		ret = PTR_ERR(dma->chan_tx);
-		if (ret != -EPROBE_DEFER)
+		if ((ret != -ENODEV) && (ret != -EPROBE_DEFER))
 			dev_err(dev, "can't request DMA tx channel\n");
 		goto fail_al;
 	}
@@ -46,7 +46,7 @@ struct stm32_i2c_dma *stm32_i2c_dma_request(struct device *dev,
 	dma->chan_rx = dma_request_chan(dev, "rx");
 	if (IS_ERR(dma->chan_rx)) {
 		ret = PTR_ERR(dma->chan_rx);
-		if (ret != -EPROBE_DEFER)
+		if ((ret != -ENODEV) && (ret != -EPROBE_DEFER))
 			dev_err(dev, "can't request DMA rx channel\n");
 
 		goto fail_tx;
@@ -76,8 +76,6 @@ fail_tx:
 	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);
 }

drivers/i2c/busses/i2c-stm32f7.c

@@ -2121,14 +2121,13 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
 	i2c_dev->dma = stm32_i2c_dma_request(i2c_dev->dev, phy_addr,
 					     STM32F7_I2C_TXDR,
 					     STM32F7_I2C_RXDR);
-	if (PTR_ERR(i2c_dev->dma) == -ENODEV)
-		i2c_dev->dma = NULL;
-	else if (IS_ERR(i2c_dev->dma)) {
+	if (IS_ERR(i2c_dev->dma)) {
 		ret = PTR_ERR(i2c_dev->dma);
-		if (ret != -EPROBE_DEFER)
-			dev_err(&pdev->dev,
-				"Failed to request dma error %i\n", ret);
-		goto fmp_clear;
+		/* DMA support is optional, only report other errors */
+		if (ret != -ENODEV)
+			goto fmp_clear;
+		dev_dbg(i2c_dev->dev, "No DMA option: fallback using interrupts\n");
+		i2c_dev->dma = NULL;
 	}
 
 	if (i2c_dev->wakeup_src) {