[PATCH v3 1/2] dt-bindings: pwm: dwc: add reset optional

[dongxuyang]

From: Xuyang Dong <dongxuyang@xxxxxxxxxxxxxxxxxx>

The DesignWare PWM controller provides separate reset signals for each
clock domain, as specified in the hardware documentation. Without
asserting and deasserting these resets during probe, PWM outputs may
remain in an undefined state after system reboot.

To address this, the driver now supports an optional 'resets' property.
A full reset is performed only when no PWM channel is enabled, as
determined by reading the enable bit in each channel's control register.
This allows safe coexistence with bootloaders that have already
configured active PWM channels.

Signed-off-by: Xuyang Dong <dongxuyang@xxxxxxxxxxxxxxxxxx>
---
 .../devicetree/bindings/pwm/snps,dw-apb-timers-pwm2.yaml       | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/pwm/snps,dw-apb-timers-pwm2.yaml b/Documentation/devicetree/bindings/pwm/snps,dw-apb-timers-pwm2.yaml
index 7523a89a1773..fd9f73c75121 100644
--- a/Documentation/devicetree/bindings/pwm/snps,dw-apb-timers-pwm2.yaml
+++ b/Documentation/devicetree/bindings/pwm/snps,dw-apb-timers-pwm2.yaml
@@ -43,6 +43,9 @@ properties:
       - const: bus
       - const: timer
 
+  resets:
+    maxItems: 1
+
   snps,pwm-number:
     $ref: /schemas/types.yaml#/definitions/uint32
     description: The number of PWM channels configured for this instance
-- 
2.34.1