Fix a shortcoming in the bindings that doesn't allow for a separate
external clock.

The AXI PWMGEN IP block has a compile option ASYNC_CLK_EN that allows
the use of an external clock for the PWM output separate from the AXI
clock that runs the peripheral.

This was missed in the original bindings and so users were writing dts
files where the one and only clock specified would be the external
clock, if there was one, incorrectly missing the separate AXI clock.

The correct bindings are that the AXI clock is always required and the
external clock is optional (must be given only when HDL compile option
ASYNC_CLK_EN=1).

Cc: stable@vger.kernel.org
Fixes: 1edf2c2a2841 ("dt-bindings: pwm: Add AXI PWM generator")
Signed-off-by: David Lechner <dlechner@baylibre.com>
---
 Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml b/Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml
index bc44381692054f647a160a6573dae4cff2ee3f31..e4c2d5186dedb18701af74bbc957b82a2b0f8737 100644
--- a/Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml
+++ b/Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml
@@ -30,11 +30,19 @@ properties:
     const: 3
 
   clocks:
-    maxItems: 1
+    minItems: 1
+    maxItems: 2
+
+  clock-names:
+    minItems: 1
+    items:
+      - const: axi
+      - const: ext
 
 required:
   - reg
   - clocks
+  - clock-names
 
 unevaluatedProperties: false
 
@@ -43,6 +51,7 @@ examples:
     pwm@44b00000 {
         compatible = "adi,axi-pwmgen-2.00.a";
         reg = <0x44b00000 0x1000>;
-        clocks = <&spi_clk>;
+        clocks = <&fpga_clk>, <&spi_clk>;
+        clock-names = "axi", "ext";
         #pwm-cells = <3>;
     };

-- 
2.43.0

On Thu, May 29, 2025 at 11:53:19AM GMT, David Lechner wrote:
> Fix a shortcoming in the bindings that doesn't allow for a separate
> external clock.
> 
> The AXI PWMGEN IP block has a compile option ASYNC_CLK_EN that allows
> the use of an external clock for the PWM output separate from the AXI
> clock that runs the peripheral.
> 
> This was missed in the original bindings and so users were writing dts
> files where the one and only clock specified would be the external
> clock, if there was one, incorrectly missing the separate AXI clock.
> 
> The correct bindings are that the AXI clock is always required and the
> external clock is optional (must be given only when HDL compile option
> ASYNC_CLK_EN=1).
> 
> Cc: stable@vger.kernel.org
> Fixes: 1edf2c2a2841 ("dt-bindings: pwm: Add AXI PWM generator")
> Signed-off-by: David Lechner <dlechner@baylibre.com>
> ---
>  Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof