[PATCH 0/2] Avoid meaningless DMA error print & use dev_err_probe

[PATCH 0/2] Avoid meaningless DMA error print & use dev_err_probe

[Alain Volmat]

This serie replaces the patch from Holger Assmann [i2c: stm32: remove
unnecessary DMA kernel error log] (1) and the first version of [i2c: stm32:
do not display error when DMA is not requested] from myself (2).

A first patch is fixing useless error print when not being able to get
DMA channel (DMA is only optional) and also avoid printing twice an error
when a real DMA error is happening.

On top of that, dev_err_probe from Krzysztof has been rebased.

[1] https://marc.info/?l=linux-i2c&m=159741480608578&w=2
[2] https://marc.info/?l=linux-i2c&m=159973040314193&w=2

Alain Volmat (1):
  i2c: stm32: fix error message on upon dma_request_chan & defer
    handling

Krzysztof Kozlowski (1):
  i2c: stm32: Simplify with dev_err_probe()

 drivers/i2c/busses/i2c-stm32.c   | 12 ++++++------
 drivers/i2c/busses/i2c-stm32f4.c |  6 ++----
 drivers/i2c/busses/i2c-stm32f7.c | 27 +++++++++++----------------
 3 files changed, 19 insertions(+), 26 deletions(-)

-- 
2.7.4

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[PATCH 1/2] i2c: stm32: fix error message on upon dma_request_chan & defer handling

[Alain Volmat]

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.

CC: Krzysztof Kozlowski <krzk@kernel.org>
CC: Holger Assmann <h.assmann@pengutronix.de>
Signed-off-by: Alain Volmat <alain.volmat@st.com>
---
This patch replaces the patch [i2c: stm32: do not display error when DMA is not requested]
previously sent on the mailing list.
---
 drivers/i2c/busses/i2c-stm32.c   |  6 ++----
 drivers/i2c/busses/i2c-stm32f7.c | 13 ++++++-------
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/i2c/busses/i2c-stm32.c b/drivers/i2c/busses/i2c-stm32.c
index 3f69a3bb6119..468620db9ea5 100644
--- a/drivers/i2c/busses/i2c-stm32.c
+++ b/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 @@ 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 bff3479fe122..8a61320a9cb9 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -2052,14 +2052,13 @@ 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) {
-- 
2.7.4


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[PATCH v2 2/2] i2c: stm32: Simplify with dev_err_probe()

[Alain Volmat]

From: Krzysztof Kozlowski <krzk@kernel.org>

Common pattern of handling deferred probe can be simplified with
dev_err_probe().  Less code and the error value gets printed.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Alain Volmat <alain.volmat@st.com>
---
v2: rebased on top of patch [i2c: stm32: fix error message on upon
dma_request_chan & defer handling]
---
 drivers/i2c/busses/i2c-stm32.c   | 10 ++++++----
 drivers/i2c/busses/i2c-stm32f4.c |  6 ++----
 drivers/i2c/busses/i2c-stm32f7.c | 14 +++++---------
 3 files changed, 13 insertions(+), 17 deletions(-)

diff --git a/drivers/i2c/busses/i2c-stm32.c b/drivers/i2c/busses/i2c-stm32.c
index 468620db9ea5..157c64e27d0b 100644
--- a/drivers/i2c/busses/i2c-stm32.c
+++ b/drivers/i2c/busses/i2c-stm32.c
@@ -26,8 +26,9 @@ 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 != -ENODEV) && (ret != -EPROBE_DEFER))
-			dev_err(dev, "can't request DMA tx channel\n");
+		if (ret != -ENODEV)
+			ret = dev_err_probe(dev, ret,
+					    "can't request DMA tx channel\n");
 		goto fail_al;
 	}
 
@@ -46,8 +47,9 @@ 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 != -ENODEV) && (ret != -EPROBE_DEFER))
-			dev_err(dev, "can't request DMA rx channel\n");
+		if (ret != -ENODEV)
+			ret = dev_err_probe(dev, ret,
+					    "can't request DMA rx channel\n");
 
 		goto fail_tx;
 	}
diff --git a/drivers/i2c/busses/i2c-stm32f4.c b/drivers/i2c/busses/i2c-stm32f4.c
index 48e269284369..937c2c8fd349 100644
--- a/drivers/i2c/busses/i2c-stm32f4.c
+++ b/drivers/i2c/busses/i2c-stm32f4.c
@@ -797,10 +797,8 @@ static int stm32f4_i2c_probe(struct platform_device *pdev)
 
 	rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
 	if (IS_ERR(rst)) {
-		ret = PTR_ERR(rst);
-		if (ret != -EPROBE_DEFER)
-			dev_err(&pdev->dev, "Error: Missing reset ctrl\n");
-
+		ret = dev_err_probe(&pdev->dev, PTR_ERR(rst),
+				    "Error: Missing reset ctrl\n");
 		goto clk_free;
 	}
 	reset_control_assert(rst);
diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index 8a61320a9cb9..0fbd964c2fe8 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -1968,11 +1968,9 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
 						    "wakeup-source");
 
 	i2c_dev->clk = devm_clk_get(&pdev->dev, NULL);
-	if (IS_ERR(i2c_dev->clk)) {
-		if (PTR_ERR(i2c_dev->clk) != -EPROBE_DEFER)
-			dev_err(&pdev->dev, "Failed to get controller clock\n");
-		return PTR_ERR(i2c_dev->clk);
-	}
+	if (IS_ERR(i2c_dev->clk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(i2c_dev->clk),
+				     "Failed to get controller clock\n");
 
 	ret = clk_prepare_enable(i2c_dev->clk);
 	if (ret) {
@@ -1982,10 +1980,8 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
 
 	rst = devm_reset_control_get(&pdev->dev, NULL);
 	if (IS_ERR(rst)) {
-		ret = PTR_ERR(rst);
-		if (ret != -EPROBE_DEFER)
-			dev_err(&pdev->dev, "Error: Missing reset ctrl\n");
-
+		ret = dev_err_probe(&pdev->dev, PTR_ERR(rst),
+				    "Error: Missing reset ctrl\n");
 		goto clk_free;
 	}
 	reset_control_assert(rst);
-- 
2.7.4


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