[PATCH] dt-bindings: pwm: st,pwm: convert to DT schema

[PATCH] dt-bindings: pwm: st,pwm: convert to DT schema

[Charan Pedumuru]

Convert STMicroelectronics STiH41x PWM/Capture controller binding
to DT schema.

Signed-off-by: Charan Pedumuru <charan.pedumuru@gmail.com>
---
 Documentation/devicetree/bindings/pwm/pwm-st.txt  | 43 -----------
 Documentation/devicetree/bindings/pwm/st,pwm.yaml | 90 +++++++++++++++++++++++
 2 files changed, 90 insertions(+), 43 deletions(-)

diff --git a/Documentation/devicetree/bindings/pwm/pwm-st.txt b/Documentation/devicetree/bindings/pwm/pwm-st.txt
deleted file mode 100644
index 19fce774cafa..000000000000
--- a/Documentation/devicetree/bindings/pwm/pwm-st.txt
+++ /dev/null
@@ -1,43 +0,0 @@
-STMicroelectronics PWM driver bindings
---------------------------------------
-
-Required parameters:
-- compatible :		"st,pwm"
-- #pwm-cells : 		Number of cells used to specify a PWM. First cell
-			specifies the per-chip index of the PWM to use and the
-			second cell is the period in nanoseconds - fixed to 2
-			for STiH41x.
-- reg :			Physical base address and length of the controller's
-			registers.
-- pinctrl-names: 	Set to "default".
-- pinctrl-0: 		List of phandles pointing to pin configuration nodes
-			for PWM module.
-			For Pinctrl properties, please refer to [1].
-- clock-names: 		Valid entries are "pwm" and/or "capture".
-- clocks: 		phandle of the clock used by the PWM module.
-			For Clk properties, please refer to [2].
-- interrupts:		IRQ for the Capture device
-
-Optional properties:
-- st,pwm-num-chan:	Number of available PWM channels.  Default is 0.
-- st,capture-num-chan:	Number of available Capture channels.  Default is 0.
-
-[1] Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
-[2] Documentation/devicetree/bindings/clock/clock-bindings.txt
-
-Example:
-
-pwm1: pwm@fe510000 {
-	compatible = "st,pwm";
-	reg = <0xfe510000 0x68>;
-	#pwm-cells = <2>;
-	pinctrl-names = "default";
-	pinctrl-0 = <&pinctrl_pwm1_chan0_default
-		     &pinctrl_pwm1_chan1_default
-		     &pinctrl_pwm1_chan2_default
-		     &pinctrl_pwm1_chan3_default>;
-	clocks = <&clk_sysin>;
-	clock-names = "pwm";
-	st,pwm-num-chan = <4>;
-	st,capture-num-chan = <2>;
-};
diff --git a/Documentation/devicetree/bindings/pwm/st,pwm.yaml b/Documentation/devicetree/bindings/pwm/st,pwm.yaml
new file mode 100644
index 000000000000..2c10f54b5caf
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/st,pwm.yaml
@@ -0,0 +1,90 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/st,pwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STMicroelectronics STiH41x PWM/Capture controller
+
+maintainers:
+  - Ajit Pal Singh <ajitpal.singh@st.com>
+
+description:
+  The STiH41x PWM controller supports both PWM output and input capture
+  functionality. It provides multiple PWM output channels for generating
+  variable duty-cycle waveforms, and multiple input capture channels for
+  measuring external signal periods and pulse widths. PWM output channels
+  and input capture channels are configured independently via
+  st,pwm-num-chan and st,capture-num-chan respectively.
+
+allOf:
+  - $ref: pwm.yaml#
+
+properties:
+  compatible:
+    const: st,pwm
+
+  reg:
+    maxItems: 1
+
+  "#pwm-cells":
+    const: 2
+
+  pinctrl-names:
+    const: default
+
+  clock-names:
+    items:
+      enum: [pwm, capture]
+    minItems: 1
+    maxItems: 2
+
+  clocks:
+    minItems: 1
+    maxItems: 2
+
+  interrupts:
+    description: IRQ line for the capture device.
+    maxItems: 1
+
+  st,pwm-num-chan:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Number of available PWM output channels.
+    minimum: 0
+    maximum: 4
+    default: 0
+
+  st,capture-num-chan:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Number of available input capture channels.
+    minimum: 0
+    maximum: 4
+    default: 0
+
+required:
+  - reg
+  - compatible
+  - "#pwm-cells"
+  - pinctrl-names
+  - clock-names
+  - clocks
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    pwm@fe510000 {
+        compatible = "st,pwm";
+        reg = <0xfe510000 0x68>;
+        #pwm-cells = <2>;
+        pinctrl-names = "default";
+        pinctrl-0 = <&pinctrl_pwm1_chan0_default
+                     &pinctrl_pwm1_chan1_default
+                     &pinctrl_pwm1_chan2_default
+                     &pinctrl_pwm1_chan3_default>;
+        clocks = <&clk_sysin>;
+        clock-names = "pwm";
+        st,pwm-num-chan = <4>;
+        st,capture-num-chan = <2>;
+    };
+...

---
base-commit: c425609d6ac4012c8bbf01ec2e10e801b1923a7b
change-id: 20260613-st-pwm-1feade6cfea3

Best regards,
--  
Charan Pedumuru <charan.pedumuru@gmail.com>

Re: [PATCH] dt-bindings: pwm: st,pwm: convert to DT schema

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The `interrupts` property is unconditionally required by the driver but omitted from the YAML schema's required list.
--

commit b16a62dff3236ec8b123a99775f6c90dbfd9912f
Author: Charan Pedumuru <charan.pedumuru@gmail.com>

dt-bindings: pwm: st,pwm: convert to DT schema

Convert STMicroelectronics STiH41x PWM/Capture controller binding
to DT schema.

> diff --git a/Documentation/devicetree/bindings/pwm/pwm-st.txt b/Documentation/devicetree/bindings/pwm/pwm-st.txt
> deleted file mode 100644
> index 19fce774cafad..0000000000000
> --- a/Documentation/devicetree/bindings/pwm/pwm-st.txt
> +++ /dev/null

[ ... ]

> -Required parameters:

[ ... ]

> -- interrupts:		IRQ for the Capture device

[ ... ]

> diff --git a/Documentation/devicetree/bindings/pwm/st,pwm.yaml b/Documentation/devicetree/bindings/pwm/st,pwm.yaml
> new file mode 100644
> index 0000000000000..2c10f54b5caf3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/st,pwm.yaml

[ ... ]

> +required:
> +  - reg
> +  - compatible
> +  - "#pwm-cells"
> +  - pinctrl-names
> +  - clock-names
> +  - clocks

[Severity: Medium]
Should interrupts be included in this required list?

The original text binding listed interrupts under the required parameters,
and the driver unconditionally requests it during probe:

drivers/pwm/pwm-sti.c:sti_pwm_probe() {
    ...
    irq = platform_get_irq(pdev, 0);
    if (irq < 0)
        return irq;

    ret = devm_request_irq(&pdev->dev, irq, sti_pwm_interrupt, 0,
                           pdev->name, pc);
    ...
}

Without interrupts in the required list, incomplete device trees will pass
schema validation but fail deterministically at runtime.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260613-st-pwm-v1-1-458c2c89709a@gmail.com?part=1

Re: [PATCH] dt-bindings: pwm: st,pwm: convert to DT schema

[Charan Pedumuru]

On 13-06-2026 12:43, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] The `interrupts` property is unconditionally required by the driver but omitted from the YAML schema's required list.
> --
> 
> commit b16a62dff3236ec8b123a99775f6c90dbfd9912f
> Author: Charan Pedumuru <charan.pedumuru@gmail.com>
> 
> dt-bindings: pwm: st,pwm: convert to DT schema
> 
> Convert STMicroelectronics STiH41x PWM/Capture controller binding
> to DT schema.
> 
>> diff --git a/Documentation/devicetree/bindings/pwm/pwm-st.txt b/Documentation/devicetree/bindings/pwm/pwm-st.txt
>> deleted file mode 100644
>> index 19fce774cafad..0000000000000
>> --- a/Documentation/devicetree/bindings/pwm/pwm-st.txt
>> +++ /dev/null
> 
> [ ... ]
> 
>> -Required parameters:
> 
> [ ... ]
> 
>> -- interrupts:		IRQ for the Capture device

Okay, I will define and add interrupts to the required.

> 
> [ ... ]
> 
>> diff --git a/Documentation/devicetree/bindings/pwm/st,pwm.yaml b/Documentation/devicetree/bindings/pwm/st,pwm.yaml
>> new file mode 100644
>> index 0000000000000..2c10f54b5caf3
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/pwm/st,pwm.yaml
> 
> [ ... ]
> 
>> +required:
>> +  - reg
>> +  - compatible
>> +  - "#pwm-cells"
>> +  - pinctrl-names
>> +  - clock-names
>> +  - clocks
> 
> [Severity: Medium]
> Should interrupts be included in this required list?
> 
> The original text binding listed interrupts under the required parameters,
> and the driver unconditionally requests it during probe:
> 
> drivers/pwm/pwm-sti.c:sti_pwm_probe() {
>     ...
>     irq = platform_get_irq(pdev, 0);
>     if (irq < 0)
>         return irq;
> 
>     ret = devm_request_irq(&pdev->dev, irq, sti_pwm_interrupt, 0,
>                            pdev->name, pc);
>     ...
> }
> 
> Without interrupts in the required list, incomplete device trees will pass
> schema validation but fail deterministically at runtime.

Okay. I will add interrupts to my next revision.

> 

-- 
Best Regards,
Charan.