[v2] pinctrl: qcom: Fix logic error when TLMM reg-names property is missing

[PATCH v2] pinctrl: qcom: Fix logic error when TLMM reg-names property is missing

Posted by yuanjie yang 2 months, 2 weeks ago

From: Yuanjie Yang <yuanjie.yang@oss.qualcomm.com>

Some Qualcomm platforms, such as sm8750.dtsi, define a single TLMM
region without the reg-names property. This is a valid and expected
configuration. However, the current code incorrectly treats the absence
of reg-names as an error, resulting in unintended behavior.

Refactor the logic to handle both cases correctly:
If only the gpio parameter is provided, default to TLMM region 0.
If both gpio and name are provided, compare the reg-names entries in the
TLMM node with the given name to select the appropriate region.

Fixes: 56ffb63749f4 ("pinctrl: qcom: add multi TLMM region option parameter")

Signed-off-by: Yuanjie Yang <yuanjie.yang@oss.qualcomm.com>

---
- optimize commit message
- optimize code structure and fix kfree issue
- rebase on tag: next-20250723
- Link to v1: https://lore.kernel.org/all/20250722054446.3432-1-yuanjie.yang@oss.qualcomm.com/

---
 drivers/pinctrl/qcom/tlmm-test.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/pinctrl/qcom/tlmm-test.c b/drivers/pinctrl/qcom/tlmm-test.c
index 7d7fff538755..e41fe7e76c80 100644
--- a/drivers/pinctrl/qcom/tlmm-test.c
+++ b/drivers/pinctrl/qcom/tlmm-test.c
@@ -581,10 +581,13 @@ static int tlmm_reg_base(struct device_node *tlmm, struct resource *res)
 	int ret;
 	int i;
 
+	if (!strcmp(tlmm_reg_name, "default_region"))
+		return of_address_to_resource(tlmm, 0, res);
+
 	count = of_property_count_strings(tlmm, "reg-names");
 	if (count <= 0) {
 		pr_err("failed to find tlmm reg name\n");
-		return count;
+		return -EINVAL;
 	}
 
 	reg_names = kcalloc(count, sizeof(char *), GFP_KERNEL);
@@ -597,19 +600,16 @@ static int tlmm_reg_base(struct device_node *tlmm, struct resource *res)
 		return -EINVAL;
 	}
 
-	if (!strcmp(tlmm_reg_name, "default_region")) {
-		ret = of_address_to_resource(tlmm, 0, res);
-	} else {
-		for (i = 0; i < count; i++) {
-			if (!strcmp(reg_names[i], tlmm_reg_name)) {
-				ret = of_address_to_resource(tlmm, i, res);
-				break;
-			}
+	for (i = 0; i < count; i++) {
+		if (!strcmp(reg_names[i], tlmm_reg_name)) {
+			ret = of_address_to_resource(tlmm, i, res);
+			break;
 		}
-		if (i == count)
-			ret = -EINVAL;
 	}
 
+	if (i == count)
+		ret = -EINVAL;
+
 	kfree(reg_names);
 
 	return ret;

base-commit: a933d3dc1968fcfb0ab72879ec304b1971ed1b9a
-- 
2.34.1

Re: [PATCH v2] pinctrl: qcom: Fix logic error when TLMM reg-names property is missing

Posted by Dmitry Baryshkov 2 months, 2 weeks ago

On Wed, Jul 23, 2025 at 03:50:24PM +0800, yuanjie yang wrote:
> From: Yuanjie Yang <yuanjie.yang@oss.qualcomm.com>
> 
> Some Qualcomm platforms, such as sm8750.dtsi, define a single TLMM
> region without the reg-names property. This is a valid and expected
> configuration. However, the current code incorrectly treats the absence
> of reg-names as an error, resulting in unintended behavior.
> 
> Refactor the logic to handle both cases correctly:
> If only the gpio parameter is provided, default to TLMM region 0.
> If both gpio and name are provided, compare the reg-names entries in the
> TLMM node with the given name to select the appropriate region.
> 
> Fixes: 56ffb63749f4 ("pinctrl: qcom: add multi TLMM region option parameter")
> 
> Signed-off-by: Yuanjie Yang <yuanjie.yang@oss.qualcomm.com>
> 
> ---
> - optimize commit message
> - optimize code structure and fix kfree issue
> - rebase on tag: next-20250723
> - Link to v1: https://lore.kernel.org/all/20250722054446.3432-1-yuanjie.yang@oss.qualcomm.com/
> 
> ---
>  drivers/pinctrl/qcom/tlmm-test.c | 22 +++++++++++-----------
>  1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/pinctrl/qcom/tlmm-test.c b/drivers/pinctrl/qcom/tlmm-test.c
> index 7d7fff538755..e41fe7e76c80 100644
> --- a/drivers/pinctrl/qcom/tlmm-test.c
> +++ b/drivers/pinctrl/qcom/tlmm-test.c
> @@ -581,10 +581,13 @@ static int tlmm_reg_base(struct device_node *tlmm, struct resource *res)
>  	int ret;
>  	int i;
>  
> +	if (!strcmp(tlmm_reg_name, "default_region"))
> +		return of_address_to_resource(tlmm, 0, res);
> +
>  	count = of_property_count_strings(tlmm, "reg-names");
>  	if (count <= 0) {
>  		pr_err("failed to find tlmm reg name\n");
> -		return count;
> +		return -EINVAL;

Why? It's better to propagate the error instead of reinventing it.

>  	}
>  
>  	reg_names = kcalloc(count, sizeof(char *), GFP_KERNEL);
> @@ -597,19 +600,16 @@ static int tlmm_reg_base(struct device_node *tlmm, struct resource *res)
>  		return -EINVAL;
>  	}
>  
> -	if (!strcmp(tlmm_reg_name, "default_region")) {
> -		ret = of_address_to_resource(tlmm, 0, res);
> -	} else {
> -		for (i = 0; i < count; i++) {
> -			if (!strcmp(reg_names[i], tlmm_reg_name)) {
> -				ret = of_address_to_resource(tlmm, i, res);
> -				break;
> -			}
> +	for (i = 0; i < count; i++) {
> +		if (!strcmp(reg_names[i], tlmm_reg_name)) {
> +			ret = of_address_to_resource(tlmm, i, res);
> +			break;
>  		}
> -		if (i == count)
> -			ret = -EINVAL;
>  	}
>  
> +	if (i == count)
> +		ret = -EINVAL;
> +
>  	kfree(reg_names);
>  
>  	return ret;
> 
> base-commit: a933d3dc1968fcfb0ab72879ec304b1971ed1b9a
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry

Re: [PATCH v2] pinctrl: qcom: Fix logic error when TLMM reg-names property is missing

Posted by yuanjiey 2 months, 2 weeks ago

On Wed, Jul 23, 2025 at 02:27:46PM +0300, Dmitry Baryshkov wrote:
> On Wed, Jul 23, 2025 at 03:50:24PM +0800, yuanjie yang wrote:
> > From: Yuanjie Yang <yuanjie.yang@oss.qualcomm.com>
> > 
> > Some Qualcomm platforms, such as sm8750.dtsi, define a single TLMM
> > region without the reg-names property. This is a valid and expected
> > configuration. However, the current code incorrectly treats the absence
> > of reg-names as an error, resulting in unintended behavior.
> > 
> > Refactor the logic to handle both cases correctly:
> > If only the gpio parameter is provided, default to TLMM region 0.
> > If both gpio and name are provided, compare the reg-names entries in the
> > TLMM node with the given name to select the appropriate region.
> > 
> > Fixes: 56ffb63749f4 ("pinctrl: qcom: add multi TLMM region option parameter")
> > 
> > Signed-off-by: Yuanjie Yang <yuanjie.yang@oss.qualcomm.com>
> > 
> > ---
> > - optimize commit message
> > - optimize code structure and fix kfree issue
> > - rebase on tag: next-20250723
> > - Link to v1: https://lore.kernel.org/all/20250722054446.3432-1-yuanjie.yang@oss.qualcomm.com/
> > 
> > ---
> >  drivers/pinctrl/qcom/tlmm-test.c | 22 +++++++++++-----------
> >  1 file changed, 11 insertions(+), 11 deletions(-)
> > 
> > diff --git a/drivers/pinctrl/qcom/tlmm-test.c b/drivers/pinctrl/qcom/tlmm-test.c
> > index 7d7fff538755..e41fe7e76c80 100644
> > --- a/drivers/pinctrl/qcom/tlmm-test.c
> > +++ b/drivers/pinctrl/qcom/tlmm-test.c
> > @@ -581,10 +581,13 @@ static int tlmm_reg_base(struct device_node *tlmm, struct resource *res)
> >  	int ret;
> >  	int i;
> >  
> > +	if (!strcmp(tlmm_reg_name, "default_region"))
> > +		return of_address_to_resource(tlmm, 0, res);
> > +
> >  	count = of_property_count_strings(tlmm, "reg-names");
> >  	if (count <= 0) {
> >  		pr_err("failed to find tlmm reg name\n");
> > -		return count;
> > +		return -EINVAL;
> 
> Why? It's better to propagate the error instead of reinventing it.

of_property_count_strings often return value > 0 (count) or value < 0 (error code).
But theoretically the return value can equal 0 (value == 0), perhaps this situation
will not happen.

However, from the code logic perspective, this tool should early return when count<=0,
if return count == 0, code flow can not stop, this will lead to a mistake in the tool. 
  line:
    639:ret = tlmm_reg_base(tlmm, &res);
    640:if (ret < 0)
    641:	return ret;  

With this consideration, I have reinvented the error code.

> >  	}
> >  
> >  	reg_names = kcalloc(count, sizeof(char *), GFP_KERNEL);
> > @@ -597,19 +600,16 @@ static int tlmm_reg_base(struct device_node *tlmm, struct resource *res)
> >  		return -EINVAL;
> >  	}
> >  
> > -	if (!strcmp(tlmm_reg_name, "default_region")) {
> > -		ret = of_address_to_resource(tlmm, 0, res);
> > -	} else {
> > -		for (i = 0; i < count; i++) {
> > -			if (!strcmp(reg_names[i], tlmm_reg_name)) {
> > -				ret = of_address_to_resource(tlmm, i, res);
> > -				break;
> > -			}
> > +	for (i = 0; i < count; i++) {
> > +		if (!strcmp(reg_names[i], tlmm_reg_name)) {
> > +			ret = of_address_to_resource(tlmm, i, res);
> > +			break;
> >  		}
> > -		if (i == count)
> > -			ret = -EINVAL;
> >  	}
> >  
> > +	if (i == count)
> > +		ret = -EINVAL;
> > +
> >  	kfree(reg_names);
> >  
> >  	return ret;
> > 
> > base-commit: a933d3dc1968fcfb0ab72879ec304b1971ed1b9a
> > -- 
> > 2.34.1
> > 
> 
> -- 
> With best wishes
> Dmitry

Thanks,
Yuanjie