[PATCH v2] dt-bindings: dma: xilinx: Add power-domains to xlnx,zynqmp-dpdma

[PATCH v2] dt-bindings: dma: xilinx: Add power-domains to xlnx,zynqmp-dpdma

[Michal Simek]

DP DMA has own power domain that's why describe optional power-domain
property.

Signed-off-by: Michal Simek <michal.simek@amd.com>
---

Changes in v2:
- rewrite commit message - requested by Krzysztof

The commit b06112cd5e08 ("arm64: dts: zynqmp: Add power domain for the
DisplayPort DMA controller") added this property already in Linux that's
why the patch is also fixing dts_check warnings.

---
 .../devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml      | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml b/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml
index 825294e3f0e8..f066f6983899 100644
--- a/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml
+++ b/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml
@@ -41,6 +41,9 @@ properties:
   clock-names:
     const: axi_clk
 
+  power-domains:
+    maxItems: 1
+
 required:
   - "#dma-cells"
   - compatible
-- 
2.36.1

Re: [PATCH v2] dt-bindings: dma: xilinx: Add power-domains to xlnx,zynqmp-dpdma

[Krzysztof Kozlowski]

On 03/05/2023 10:00, Michal Simek wrote:
> DP DMA has own power domain that's why describe optional power-domain
> property.
> 
> Signed-off-by: Michal Simek <michal.simek@amd.com>
> ---
> 
> Changes in v2:
> - rewrite commit message - requested by Krzysztof
> 
> The commit b06112cd5e08 ("arm64: dts: zynqmp: Add power domain for the
> DisplayPort DMA controller") added this property already in Linux that's
> why the patch is also fixing dts_check warnings.


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

Best regards,
Krzysztof

Re: [PATCH v2] dt-bindings: dma: xilinx: Add power-domains to xlnx,zynqmp-dpdma

[Laurent Pinchart]

Hi Michal,

Thank you for the patch.

On Wed, May 03, 2023 at 10:00:20AM +0200, Michal Simek wrote:
> DP DMA has own power domain that's why describe optional power-domain
> property.

As far as I understand, the property should always be specified, the
only reason why it's not mandatory is backward-compatibility (I would
make it mandatory, as I think proper validation of new DT is more
important than avoiding breaking validation - but not operation! - of
old DT, but that's a separate story). If my understanding is correct,
could you please update the example in the bindings to add the
power-domains property ?

> Signed-off-by: Michal Simek <michal.simek@amd.com>
> ---
> 
> Changes in v2:
> - rewrite commit message - requested by Krzysztof
> 
> The commit b06112cd5e08 ("arm64: dts: zynqmp: Add power domain for the
> DisplayPort DMA controller") added this property already in Linux that's
> why the patch is also fixing dts_check warnings.
> 
> ---
>  .../devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml      | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml b/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml
> index 825294e3f0e8..f066f6983899 100644
> --- a/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml
> +++ b/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml
> @@ -41,6 +41,9 @@ properties:
>    clock-names:
>      const: axi_clk
>  
> +  power-domains:
> +    maxItems: 1
> +
>  required:
>    - "#dma-cells"
>    - compatible

-- 
Regards,

Laurent Pinchart

Re: [PATCH v2] dt-bindings: dma: xilinx: Add power-domains to xlnx,zynqmp-dpdma

[Michal Simek]

Hi,

On 5/3/23 14:51, Laurent Pinchart wrote:
> Hi Michal,
> 
> Thank you for the patch.
> 
> On Wed, May 03, 2023 at 10:00:20AM +0200, Michal Simek wrote:
>> DP DMA has own power domain that's why describe optional power-domain
>> property.
> 
> As far as I understand, the property should always be specified, the
> only reason why it's not mandatory is backward-compatibility (I would
> make it mandatory, as I think proper validation of new DT is more
> important than avoiding breaking validation - but not operation! - of
> old DT, but that's a separate story). If my understanding is correct,
> could you please update the example in the bindings to add the
> power-domains property ?

backward compatible - of course
always specified - if pd driver is enabled it must be there. If not it doesn't 
do anything - just describes it.

I am not in a position to decide this. But if dt folks agree with your ask I am 
happy to make it mandatory and extend example.

M

Re: [PATCH v2] dt-bindings: dma: xilinx: Add power-domains to xlnx,zynqmp-dpdma

[Krzysztof Kozlowski]

On 03/05/2023 15:27, Michal Simek wrote:
> Hi,
> 
> On 5/3/23 14:51, Laurent Pinchart wrote:
>> Hi Michal,
>>
>> Thank you for the patch.
>>
>> On Wed, May 03, 2023 at 10:00:20AM +0200, Michal Simek wrote:
>>> DP DMA has own power domain that's why describe optional power-domain
>>> property.
>>
>> As far as I understand, the property should always be specified, the
>> only reason why it's not mandatory is backward-compatibility (I would
>> make it mandatory, as I think proper validation of new DT is more
>> important than avoiding breaking validation - but not operation! - of
>> old DT, but that's a separate story). If my understanding is correct,
>> could you please update the example in the bindings to add the
>> power-domains property ?
> 
> backward compatible - of course
> always specified - if pd driver is enabled it must be there. If not it doesn't 
> do anything - just describes it.
> 
> I am not in a position to decide this. But if dt folks agree with your ask I am 
> happy to make it mandatory and extend example.

By making it mandatory in the bindings only, not in the driver, no real
ABI gets broken. Linux won't stop booting if property is missing.
Therefore if device is always part of power domain and it is actually
required, then sure - making it required is useful.

Best regards,
Krzysztof