[PATCH v2 1/3] pwm: pwm-mediatek: Simplify error handling with dev_err_probe()

[PATCH v2 1/3] pwm: pwm-mediatek: Simplify error handling with dev_err_probe()

[AngeloGioacchino Del Regno]

Use dev_err_probe() to simplify handling errors in pwm_mediatek_probe().

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/pwm/pwm-mediatek.c | 30 +++++++++++-------------------
 1 file changed, 11 insertions(+), 19 deletions(-)

diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
index 0d4dd80e9f07..c7d5ca09a684 100644
--- a/drivers/pwm/pwm-mediatek.c
+++ b/drivers/pwm/pwm-mediatek.c
@@ -227,18 +227,14 @@ static int pwm_mediatek_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	pc->clk_top = devm_clk_get(&pdev->dev, "top");
-	if (IS_ERR(pc->clk_top)) {
-		dev_err(&pdev->dev, "clock: top fail: %ld\n",
-			PTR_ERR(pc->clk_top));
-		return PTR_ERR(pc->clk_top);
-	}
+	if (IS_ERR(pc->clk_top))
+		return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk_top),
+				     "clock: top failed\n");
 
 	pc->clk_main = devm_clk_get(&pdev->dev, "main");
-	if (IS_ERR(pc->clk_main)) {
-		dev_err(&pdev->dev, "clock: main fail: %ld\n",
-			PTR_ERR(pc->clk_main));
-		return PTR_ERR(pc->clk_main);
-	}
+	if (IS_ERR(pc->clk_main))
+		return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk_main),
+				     "clock: main failed\n");
 
 	for (i = 0; i < pc->soc->num_pwms; i++) {
 		char name[8];
@@ -246,11 +242,9 @@ static int pwm_mediatek_probe(struct platform_device *pdev)
 		snprintf(name, sizeof(name), "pwm%d", i + 1);
 
 		pc->clk_pwms[i] = devm_clk_get(&pdev->dev, name);
-		if (IS_ERR(pc->clk_pwms[i])) {
-			dev_err(&pdev->dev, "clock: %s fail: %ld\n",
-				name, PTR_ERR(pc->clk_pwms[i]));
-			return PTR_ERR(pc->clk_pwms[i]);
-		}
+		if (IS_ERR(pc->clk_pwms[i]))
+			return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk_pwms[i]),
+					     "clock: %s failed\n", name);
 	}
 
 	pc->chip.dev = &pdev->dev;
@@ -258,10 +252,8 @@ static int pwm_mediatek_probe(struct platform_device *pdev)
 	pc->chip.npwm = pc->soc->num_pwms;
 
 	ret = devm_pwmchip_add(&pdev->dev, &pc->chip);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
-		return ret;
-	}
+	if (ret < 0)
+		return dev_err_probe(&pdev->dev, ret, "pwmchip_add() failed\n");
 
 	return 0;
 }
-- 
2.33.1


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[PATCH v2 2/3] pwm: pwm-mediatek: Allocate clk_pwms with devm_kmalloc_array

[AngeloGioacchino Del Regno]

Switch from devm_kcalloc to devm_kmalloc_array when allocating clk_pwms,
as this structure is being filled right after allocating it, hence
there is no need to zero it out beforehand.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/pwm/pwm-mediatek.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
index c7d5ca09a684..6b39f3d69e41 100644
--- a/drivers/pwm/pwm-mediatek.c
+++ b/drivers/pwm/pwm-mediatek.c
@@ -221,7 +221,7 @@ static int pwm_mediatek_probe(struct platform_device *pdev)
 	if (IS_ERR(pc->regs))
 		return PTR_ERR(pc->regs);
 
-	pc->clk_pwms = devm_kcalloc(&pdev->dev, pc->soc->num_pwms,
+	pc->clk_pwms = devm_kmalloc_array(&pdev->dev, pc->soc->num_pwms,
 				    sizeof(*pc->clk_pwms), GFP_KERNEL);
 	if (!pc->clk_pwms)
 		return -ENOMEM;
-- 
2.33.1


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[PATCH v2 3/3] pwm: pwm-mediatek: Beautify error messages text

[AngeloGioacchino Del Regno]

As a cherry-on-top cleanup, make error messages clearer to read
by changing instances of "clock: XXXX failed" to a more readable
"Failed to get XXXX clock". Also add "of" to unsupported period
error.

This is purely a cosmetic change; no "real" functional changes.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/pwm/pwm-mediatek.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
index 6b39f3d69e41..568b13a48717 100644
--- a/drivers/pwm/pwm-mediatek.c
+++ b/drivers/pwm/pwm-mediatek.c
@@ -146,7 +146,7 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm,
 
 	if (clkdiv > PWM_CLK_DIV_MAX) {
 		pwm_mediatek_clk_disable(chip, pwm);
-		dev_err(chip->dev, "period %d not supported\n", period_ns);
+		dev_err(chip->dev, "period of %d ns not supported\n", period_ns);
 		return -EINVAL;
 	}
 
@@ -229,12 +229,12 @@ static int pwm_mediatek_probe(struct platform_device *pdev)
 	pc->clk_top = devm_clk_get(&pdev->dev, "top");
 	if (IS_ERR(pc->clk_top))
 		return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk_top),
-				     "clock: top failed\n");
+				     "Failed to get top clock\n");
 
 	pc->clk_main = devm_clk_get(&pdev->dev, "main");
 	if (IS_ERR(pc->clk_main))
 		return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk_main),
-				     "clock: main failed\n");
+				     "Failed to get main clock\n");
 
 	for (i = 0; i < pc->soc->num_pwms; i++) {
 		char name[8];
@@ -244,7 +244,7 @@ static int pwm_mediatek_probe(struct platform_device *pdev)
 		pc->clk_pwms[i] = devm_clk_get(&pdev->dev, name);
 		if (IS_ERR(pc->clk_pwms[i]))
 			return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk_pwms[i]),
-					     "clock: %s failed\n", name);
+					     "Failed to get %s clock\n", name);
 	}
 
 	pc->chip.dev = &pdev->dev;
-- 
2.33.1


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Re: [PATCH v2 1/3] pwm: pwm-mediatek: Simplify error handling with dev_err_probe()

[Thierry Reding]

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On Mon, Feb 14, 2022 at 03:03:37PM +0100, AngeloGioacchino Del Regno wrote:
> Use dev_err_probe() to simplify handling errors in pwm_mediatek_probe().
> 
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
>  drivers/pwm/pwm-mediatek.c | 30 +++++++++++-------------------
>  1 file changed, 11 insertions(+), 19 deletions(-)

Applied, thanks.

Thierry

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Re: [PATCH v2 2/3] pwm: pwm-mediatek: Allocate clk_pwms with devm_kmalloc_array

[Thierry Reding]

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On Mon, Feb 14, 2022 at 03:03:38PM +0100, AngeloGioacchino Del Regno wrote:
> Switch from devm_kcalloc to devm_kmalloc_array when allocating clk_pwms,
> as this structure is being filled right after allocating it, hence
> there is no need to zero it out beforehand.
> 
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
>  drivers/pwm/pwm-mediatek.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied, thanks.

Thierry

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Re: [PATCH v2 3/3] pwm: pwm-mediatek: Beautify error messages text

[Thierry Reding]

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On Tue, Feb 15, 2022 at 02:47:33PM +0800, Macpaul Lin wrote:
> On 2/14/22 10:03 PM, AngeloGioacchino Del Regno wrote:
> > As a cherry-on-top cleanup, make error messages clearer to read
> > by changing instances of "clock: XXXX failed" to a more readable
> > "Failed to get XXXX clock". Also add "of" to unsupported period
> > error.
> > 
> > This is purely a cosmetic change; no "real" functional changes.
> > 
> > Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> > ---
> >   drivers/pwm/pwm-mediatek.c | 8 ++++----
> >   1 file changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
> > index 6b39f3d69e41..568b13a48717 100644
> > --- a/drivers/pwm/pwm-mediatek.c
> > +++ b/drivers/pwm/pwm-mediatek.c
> > @@ -146,7 +146,7 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm,
> >   	if (clkdiv > PWM_CLK_DIV_MAX) {
> >   		pwm_mediatek_clk_disable(chip, pwm);
> > -		dev_err(chip->dev, "period %d not supported\n", period_ns);
> > +		dev_err(chip->dev, "period of %d ns not supported\n", period_ns);
> >   		return -EINVAL;
> >   	}
> > @@ -229,12 +229,12 @@ static int pwm_mediatek_probe(struct platform_device *pdev)
> >   	pc->clk_top = devm_clk_get(&pdev->dev, "top");
> >   	if (IS_ERR(pc->clk_top))
> >   		return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk_top),
> > -				     "clock: top failed\n");
> > +				     "Failed to get top clock\n");
> >   	pc->clk_main = devm_clk_get(&pdev->dev, "main");
> >   	if (IS_ERR(pc->clk_main))
> >   		return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk_main),
> > -				     "clock: main failed\n");
> > +				     "Failed to get main clock\n");
> >   	for (i = 0; i < pc->soc->num_pwms; i++) {
> >   		char name[8];
> > @@ -244,7 +244,7 @@ static int pwm_mediatek_probe(struct platform_device *pdev)
> >   		pc->clk_pwms[i] = devm_clk_get(&pdev->dev, name);
> >   		if (IS_ERR(pc->clk_pwms[i]))
> >   			return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk_pwms[i]),
> > -					     "clock: %s failed\n", name);
> > +					     "Failed to get %s clock\n", name);
> >   	}
> >   	pc->chip.dev = &pdev->dev;
> > 
> 
> The format of these debug messages "clock: top" or "clock: main" is meant to
> keep both human and machine's readability at the same time.
> This kind of format is much more easier to parse by scripts, which the
> driver's category and sub nodes are separated by delimiters . If a fail log
> has been provided, the script could indicated where the issue might exists
> probably. Device vender, field application engineer, and driver maintainer
> could be able to write and use the error log parser before debugging.

Does such a script truly exist? Given that most error messages don't
follow this format, I would expect it to be only very marginally useful.
Typically the prefix that the dev_printk() variants add is enough
information to deduct where the error happens, at which point it's back
to good old grep to find the matching string to localize exactly.

> I'm not sure if this kind of format will be better. Like, "Failed to get
> clock: %s".
> 
> If most people like this kind of solution ("Failed to get clock: %s\n"),
> then you can have the reviewed-by tag.
> Thanks!
> 
> Reviewed-by: Macpaul Lin <macpaul.lin@mediatek.com>

I'm going to assume that the scriptability is a theoretical argument, so
I'll take this. Let me know if you do rely on the exact format and I can
drop this again.

Thierry

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