[PATCH] pinctrl: meson: amlogic-a4: use nolock get range

[PATCH] pinctrl: meson: amlogic-a4: use nolock get range

[Xianwei Zhao via B4 Relay]

From: Xianwei Zhao <xianwei.zhao@amlogic.com>

Use pinctrl_find_gpio_range_from_pin_nolock() instead of
pinctrl_find_gpio_range_from_pin() when configuring a pin or
setting a GPIO value.

This avoids taking the lock and allows the code to be safely
called from interrupt context.

Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
---
Use pinctrl_find_gpio_range_from_pin_nolock 
when configuring a pin or setting a GPIO value.
---
 drivers/pinctrl/meson/pinctrl-amlogic-a4.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
index 5ae0c19d007d..420f7915c010 100644
--- a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
+++ b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
@@ -300,7 +300,7 @@ static int aml_pmx_set_mux(struct pinctrl_dev *pctldev, unsigned int fselector,
 	int i;
 
 	for (i = 0; i < group->npins; i++) {
-		range =  pinctrl_find_gpio_range_from_pin(pctldev, group->pins[i]);
+		range =  pinctrl_find_gpio_range_from_pin_nolock(pctldev, group->pins[i]);
 		aml_pctl_set_function(info, range, group->pins[i], group->func[i]);
 	}
 
@@ -499,7 +499,7 @@ static int aml_pinconf_disable_bias(struct aml_pinctrl *info,
 				    unsigned int pin)
 {
 	struct pinctrl_gpio_range *range =
-			 pinctrl_find_gpio_range_from_pin(info->pctl, pin);
+			 pinctrl_find_gpio_range_from_pin_nolock(info->pctl, pin);
 	struct aml_gpio_bank *bank = gpio_chip_to_bank(range->gc);
 	unsigned int reg, bit = 0;
 
@@ -512,7 +512,7 @@ static int aml_pinconf_enable_bias(struct aml_pinctrl *info, unsigned int pin,
 				   bool pull_up)
 {
 	struct pinctrl_gpio_range *range =
-			 pinctrl_find_gpio_range_from_pin(info->pctl, pin);
+			 pinctrl_find_gpio_range_from_pin_nolock(info->pctl, pin);
 	struct aml_gpio_bank *bank = gpio_chip_to_bank(range->gc);
 	unsigned int reg, bit, val = 0;
 	int ret;
@@ -534,7 +534,7 @@ static int aml_pinconf_set_drive_strength(struct aml_pinctrl *info,
 					  u16 drive_strength_ua)
 {
 	struct pinctrl_gpio_range *range =
-			 pinctrl_find_gpio_range_from_pin(info->pctl, pin);
+			 pinctrl_find_gpio_range_from_pin_nolock(info->pctl, pin);
 	struct aml_gpio_bank *bank = gpio_chip_to_bank(range->gc);
 	unsigned int reg, bit, ds_val;
 
@@ -569,7 +569,7 @@ static int aml_pinconf_set_gpio_bit(struct aml_pinctrl *info,
 				    bool arg)
 {
 	struct pinctrl_gpio_range *range =
-			 pinctrl_find_gpio_range_from_pin(info->pctl, pin);
+			 pinctrl_find_gpio_range_from_pin_nolock(info->pctl, pin);
 	struct aml_gpio_bank *bank = gpio_chip_to_bank(range->gc);
 	unsigned int reg, bit;
 

---
base-commit: aca7f93a3eba55962d3448ed005f84daabe37c5f
change-id: 20260611-pinctrl-nolock-2f93ff2d61eb

Best regards,
-- 
Xianwei Zhao <xianwei.zhao@amlogic.com>



_______________________________________________
linux-amlogic mailing list
linux-amlogic@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic

Re: [PATCH] pinctrl: meson: amlogic-a4: use nolock get range

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:

New issues:
- [High] Lockless iteration of `pctldev->gpio_ranges` introduces a data race against concurrent list modifications.

Pre-existing issues:
- [High] Missing validation of `pinctrl_find_gpio_range_from_pin_nolock()` return value leading to NULL pointer dereference.
--

commit f9e63102e7090909caca32b069c2328643c7a837
Author: Xianwei Zhao <xianwei.zhao@amlogic.com>

pinctrl: meson: amlogic-a4: use nolock get range

This commit updates the amlogic-a4 pinctrl driver to use the nolock
variant of pinctrl_find_gpio_range_from_pin() when configuring pins or
setting GPIO values. This avoids taking the lock and allows the code to be
safely called from interrupt context.

> diff --git a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
> index 35d27626a336b..29702b363e222 100644
> --- a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
> +++ b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
> @@ -250,7 +250,7 @@ static int aml_pmx_set_mux(struct pinctrl_dev *pctldev, unsigned int fselector,
>  	int i;
>  
>  	for (i = 0; i < group->npins; i++) {
> -		range =  pinctrl_find_gpio_range_from_pin(pctldev, group->pins[i]);
> +		range =  pinctrl_find_gpio_range_from_pin_nolock(pctldev, group->pins[i]);

[Severity: High]
Can this introduce a data race against concurrent list modifications?

The pctldev->gpio_ranges list is a standard doubly-linked list. Functions
like aml_pmx_set_mux() can be reached via pinctrl_select_state(), which
does not hold pctldev->mutex.

Because aml_pctl_probe() exposes the pinctrl device globally via
devm_pinctrl_register() before adding GPIO ranges via gpiochip_add_data(),
concurrent consumer probes could invoke these lockless traversals exactly
while list_add_tail() is actively mutating the list under pctldev->mutex.
Could this traverse corrupted list pointers and cause an infinite loop or
kernel panic?

[Severity: High]
This is a pre-existing issue, but does this missing NULL check lead to a
dereference if a pin is not found?

If a requested pin does not belong to any registered GPIO range,
pinctrl_find_gpio_range_from_pin_nolock() returns NULL. The returned range
pointer is then passed directly to aml_pctl_set_function() which
immediately dereferences it via range->gc in the gpio_chip_to_bank() macro:

aml_pctl_set_function()
    struct aml_gpio_bank *bank = gpio_chip_to_bank(range->gc);

>  		aml_pctl_set_function(info, range, group->pins[i], group->func[i]);
>  	}
>  

[ ... ]

> @@ -449,7 +449,7 @@ static int aml_pinconf_disable_bias(struct aml_pinctrl *info,
>  				    unsigned int pin)
>  {
>  	struct pinctrl_gpio_range *range =
> -			 pinctrl_find_gpio_range_from_pin(info->pctl, pin);
> +			 pinctrl_find_gpio_range_from_pin_nolock(info->pctl, pin);
>  	struct aml_gpio_bank *bank = gpio_chip_to_bank(range->gc);

[Severity: High]
This is a pre-existing issue, but as with aml_pmx_set_mux(), the return
value of pinctrl_find_gpio_range_from_pin_nolock() is immediately
dereferenced via range->gc. Should there be a check for NULL here as well?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260611-pinctrl-nolock-v1-1-aca022d4d60f@amlogic.com?part=1

_______________________________________________
linux-amlogic mailing list
linux-amlogic@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic

Re: [PATCH] pinctrl: meson: amlogic-a4: use nolock get range

[Linus Walleij]

On Thu, Jun 11, 2026 at 9:10 AM Xianwei Zhao via B4 Relay
<devnull+xianwei.zhao.amlogic.com@kernel.org> wrote:

> From: Xianwei Zhao <xianwei.zhao@amlogic.com>
>
> Use pinctrl_find_gpio_range_from_pin_nolock() instead of
> pinctrl_find_gpio_range_from_pin() when configuring a pin or
> setting a GPIO value.
>
> This avoids taking the lock and allows the code to be safely
> called from interrupt context.
>
> Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>

Patch applied!

Yours,
Linus Walleij

_______________________________________________
linux-amlogic mailing list
linux-amlogic@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic