[PATCH RFC 0/2] pinctrl: Add support gpiod_to_irq

[PATCH RFC 0/2] pinctrl: Add support gpiod_to_irq

[Xianwei Zhao via B4 Relay]

Some users need to obtain an IRQ directly from a GPIO descriptor through gpiod_to_irq().
Add the required DT binding and implementation to support this use case.
Since this introduces a new DT property, the property is kept optional to
maintain compatibility with existing SoCs and DTS files.

Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
---
Xianwei Zhao (2):
      dt-bindings: pinctl: amlogic,pinctrl-a4: Add gpio irq property
      pinctrl: meson: amlogic-a4: support gpiod_to_irq

 .../bindings/pinctrl/amlogic,pinctrl-a4.yaml       |  5 ++
 drivers/pinctrl/meson/pinctrl-amlogic-a4.c         | 54 ++++++++++++++++++++++
 2 files changed, 59 insertions(+)
---
base-commit: 4ca496f6285e16d91751e5c84c6010e03285528c
change-id: 20260520-gpio-to-irq-be4797d2a23f

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

[PATCH RFC 1/2] dt-bindings: pinctl: amlogic,pinctrl-a4: Add gpio irq property

[Xianwei Zhao via B4 Relay]

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

Add the hw-irq property for each GPIO bank and enable interrupt-parent
for pinctrl so that gpiod_to_irq() can translate GPIO lines to IRQs.

Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
---
 Documentation/devicetree/bindings/pinctrl/amlogic,pinctrl-a4.yaml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/pinctrl/amlogic,pinctrl-a4.yaml b/Documentation/devicetree/bindings/pinctrl/amlogic,pinctrl-a4.yaml
index b69db1b95345..65ec9121300e 100644
--- a/Documentation/devicetree/bindings/pinctrl/amlogic,pinctrl-a4.yaml
+++ b/Documentation/devicetree/bindings/pinctrl/amlogic,pinctrl-a4.yaml
@@ -37,6 +37,8 @@ properties:
 
   ranges: true
 
+  interrupt-parent: true
+
 patternProperties:
   "^gpio@[0-9a-f]+$":
     type: object
@@ -65,6 +67,9 @@ patternProperties:
       gpio-ranges:
         maxItems: 1
 
+      hw-irq:
+        $ref: /schemas/types.yaml#/definitions/uint32
+
     required:
       - reg
       - reg-names

-- 
2.52.0

[PATCH RFC 2/2] pinctrl: meson: amlogic-a4: support gpiod_to_irq

[Xianwei Zhao via B4 Relay]

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

Add the to_irq() callback implementation so that
gpiod_to_irq() can map GPIO lines to IRQs correctly.

Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
---
 drivers/pinctrl/meson/pinctrl-amlogic-a4.c | 54 ++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
index 5ae0c19d007d..663681887f35 100644
--- a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
+++ b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
@@ -10,6 +10,7 @@
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_irq.h>
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
@@ -97,6 +98,8 @@ struct aml_gpio_bank {
 	struct regmap			*reg_gpio;
 	struct regmap			*reg_ds;
 	const struct multi_mux		*p_mux;
+	struct device_node		*of_irq;
+	u32				irq_start;
 };
 
 struct aml_pinctrl {
@@ -836,6 +839,32 @@ static int aml_pctl_parse_functions(struct device_node *np,
 	return 0;
 }
 
+static struct device_node *aml_get_of_irq(struct device_node *np)
+{
+	struct device_node *of_irq;
+
+	of_irq = of_irq_find_parent(np);
+	if (of_irq && of_device_is_compatible(of_irq, "amlogic,meson-gpio-intc")) {
+		of_node_put(of_irq);
+		return of_irq;
+	}
+
+	if (of_irq)
+		of_node_put(of_irq);
+
+	return NULL;
+}
+
+static u32 aml_bank_irq(struct device_node *np)
+{
+	u32 hw_irq;
+
+	if (of_property_read_u32(np, "hw-irq", &hw_irq))
+		return U32_MAX;
+
+	return hw_irq;
+}
+
 static u32 aml_bank_pins(struct device_node *np)
 {
 	struct of_phandle_args of_args;
@@ -1003,6 +1032,27 @@ static int aml_gpio_get(struct gpio_chip *chip, unsigned int gpio)
 	return !!(val & BIT(bit));
 }
 
+static int aml_gpio_to_irq(struct gpio_chip *chip, unsigned int gpio)
+{
+	struct aml_gpio_bank *bank = gpiochip_get_data(chip);
+	struct irq_fwspec fwspec;
+	int hwirq;
+
+	if (bank->irq_start == U32_MAX)
+		return -EINVAL;
+	if (!bank->of_irq)
+		return -EINVAL;
+
+	hwirq = gpio + bank->irq_start;
+
+	fwspec.fwnode = of_fwnode_handle(bank->of_irq);
+	fwspec.param_count = 2;
+	fwspec.param[0] = hwirq;
+	fwspec.param[1] = IRQ_TYPE_NONE;
+
+	return irq_create_fwspec_mapping(&fwspec);
+}
+
 static const struct gpio_chip aml_gpio_template = {
 	.request		= gpiochip_generic_request,
 	.free			= gpiochip_generic_free,
@@ -1012,6 +1062,7 @@ static const struct gpio_chip aml_gpio_template = {
 	.direction_input	= aml_gpio_direction_input,
 	.direction_output	= aml_gpio_direction_output,
 	.get_direction		= aml_gpio_get_direction,
+	.to_irq			= aml_gpio_to_irq,
 	.can_sleep		= true,
 };
 
@@ -1079,6 +1130,7 @@ static int aml_gpiolib_register_bank(struct aml_pinctrl *info,
 		bank->reg_ds = bank->reg_gpio;
 	}
 
+	bank->irq_start = aml_bank_irq(np);
 	bank->gpio_chip = aml_gpio_template;
 	bank->gpio_chip.base = -1;
 	bank->gpio_chip.ngpio = aml_bank_pins(np);
@@ -1154,6 +1206,8 @@ static int aml_pctl_probe_dt(struct platform_device *pdev,
 				pdesc->name = pin_names[j];
 				pdesc++;
 			}
+
+			info->banks[bank].of_irq = aml_get_of_irq(np);
 			bank++;
 		} else {
 			ret = aml_pctl_parse_functions(child, info,

-- 
2.52.0

Re: [PATCH RFC 2/2] pinctrl: meson: amlogic-a4: support gpiod_to_irq

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Premature `of_node_put()` in `aml_get_of_irq()` creates a dangling pointer, leading to a Use-After-Free.
--

commit 682e8ff8b51a310ddf41177d04828ab2fd8a5670
Author: Xianwei Zhao <xianwei.zhao@amlogic.com>

pinctrl: meson: amlogic-a4: support gpiod_to_irq

This patch adds the to_irq() callback implementation so that gpiod_to_irq()
can map GPIO lines to IRQs correctly.

> diff --git a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
> index 5ae0c19d007d7..663681887f35c 100644
> --- a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
> +++ b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c

[ ... ]

> @@ -836,6 +839,32 @@ static int aml_pctl_parse_functions(struct device_node *np,
>  	return 0;
>  }
>  
> +static struct device_node *aml_get_of_irq(struct device_node *np)
> +{
> +	struct device_node *of_irq;
> +
> +	of_irq = of_irq_find_parent(np);
> +	if (of_irq && of_device_is_compatible(of_irq, "amlogic,meson-gpio-intc")) {
> +		of_node_put(of_irq);
> +		return of_irq;

[Severity: High]
Does this premature of_node_put() call create a use-after-free risk?

of_irq_find_parent() returns a device node with an incremented reference
count. By calling of_node_put() before returning the pointer, the reference
is dropped while the pointer is still passed back and cached in bank->of_irq.

Later, aml_gpio_to_irq() dereferences this pointer:

    fwspec.fwnode = of_fwnode_handle(bank->of_irq);

If the device node is dynamically freed (for example, during Device Tree
overlay removal) between caching and use, this would lead to a
use-after-free. Should we retain the reference here until driver teardown
instead?

> +	}
> +
> +	if (of_irq)
> +		of_node_put(of_irq);
> +
> +	return NULL;
> +}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260611-gpio-to-irq-v1-0-12201716f23f@amlogic.com?part=2

Re: [PATCH RFC 1/2] dt-bindings: pinctl: amlogic,pinctrl-a4: Add gpio irq property

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:
- [Medium] The newly added `hw-irq` property is not marked as required for the GPIO banks, and the example is not updated.
- [Medium] The custom device tree property `hw-irq` lacks a vendor prefix.
- [Low] The newly added `hw-irq` property lacks a description field.
--

commit 779e29b8c4c1e37224d568880fcfcc77220c1d72
Author: Xianwei Zhao <xianwei.zhao@amlogic.com>

dt-bindings: pinctl: amlogic,pinctrl-a4: Add gpio irq property

Add the hw-irq property for each GPIO bank and enable interrupt-parent
for pinctrl so that gpiod_to_irq() can translate GPIO lines to IRQs.

> diff --git a/Documentation/devicetree/bindings/pinctrl/amlogic,pinctrl-a4.yaml b/Documentation/devicetree/bindings/pinctrl/amlogic,pinctrl-a4.yaml
> --- a/Documentation/devicetree/bindings/pinctrl/amlogic,pinctrl-a4.yaml
> +++ b/Documentation/devicetree/bindings/pinctrl/amlogic,pinctrl-a4.yaml

[ ... ]

> @@ -65,6 +67,9 @@ patternProperties:
>        gpio-ranges:
>          maxItems: 1
>  
> +      hw-irq:
> +        $ref: /schemas/types.yaml#/definitions/uint32

[Severity: Medium]
Should this custom property have a vendor prefix to prevent namespace
collisions, such as amlogic,hw-irq? 

[Severity: Low]
Would it be helpful to include a description field here to document the
purpose and semantic usage of this new property?

> +
>      required:
>        - reg
>        - reg-names

[Severity: Medium]
The commit message indicates this property is added for each GPIO bank.
Should hw-irq be included in this required list under the 
patternProperties:^gpio@[0-9a-f]+$ node to ensure incomplete configurations
fail schema validation?

Additionally, the example at the bottom of the file doesn't seem to include
this new property:

examples:
  ...
    gpio@4240 {
        reg = <0 0x4240 0 0x40>, <0 0x4000 0 0x8>;
        reg-names = "gpio", "mux";
        gpio-controller;
        #gpio-cells = <2>;
        gpio-ranges = <&periphs_pinctrl 0 8 10>;
    };

Does the example section need to be updated to demonstrate the usage of the
newly added property?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260611-gpio-to-irq-v1-0-12201716f23f@amlogic.com?part=1

Re: [PATCH RFC 0/2] pinctrl: Add support gpiod_to_irq

[Linus Walleij]

Hi Xianwei,

thanks for your patches!

On Thu, Jun 11, 2026 at 9:54 AM Xianwei Zhao via B4 Relay
<devnull+xianwei.zhao.amlogic.com@kernel.org> wrote:

> Some users need to obtain an IRQ directly from a GPIO descriptor through gpiod_to_irq().
> Add the required DT binding and implementation to support this use case.
> Since this introduces a new DT property, the property is kept optional to
> maintain compatibility with existing SoCs and DTS files.

To me it looks like you have just re-implemented hierarchical
irqs.

Look into the section "Infrastructure helpers for GPIO irqchips"
in Documentation/driver-api/gpio/driver.rst, especially towards
the end.

Solve this by using GPIOLIB_IRQCHIP and a custom
child_to_parent_hwirq() callback to translate the GPIO into
an IRQ.

To just implement gpiod_to_irq() without any irqchip abstraction
is also broken: you can't force all users to just use this way
to get an IRQ it's excessively restricting.

Add

  interrupt-controller: true

  "#interrupt-cells":
    const: 2

to the pinctrl node as well so that DT users can simply request
the IRQ from the irqchip inside of the pin controller. It will
be hierarchical and lightweight but an irqchip nevertheless.

The GPIOLIB_IRQCHIP approach will help you to get this
right.

Yours,
Linus Walleij