On 20/03/2024 17:37, Rob Herring wrote:
On Tue, Mar 19, 2024 at 10:22:37AM +0200, Tomi Valkeinen wrote:
The DP subsystem for ZynqMP support audio via two channels, and the DP
DMA has dma-engines for those channels. For some reason the DT binding
has not specified those channels, even if the picture included in
xlnx,zynqmp-dpsub.yaml shows "2 x aud" DMAs.
New required entries is an ABI change. This message kind of indicates it
was a mistake, but should be a lot more explicit. Are things broken
without the entries? Need 'Fixes'?
I'll improve the desc for the next version.
So, yes, it's an ABI change, and as far as I can guess (I can't figure
out any other reason), the audio DMAs were left out by mistake or
misunderstanding. The Linux driver has not supported audio, so this has
not been an issue and nothing is broken.
Now that this series adds the audio support, I had to add the audio
DMAs. I considered making the DMAs optional in the DT, but that doesn't
sound right, even if that would keep the ABI compatibility (wouldn't
it?). The driver I add in this series does consider the audio DMAs as
optional, though. If they're not present, the driver will continue
without audio support.
So, strictly speaking I think this is a fix to the original commit that
adds the DT node, but as the driver using the audio DMAs comes in only
now, I think there's no need for the 'Fixes' and backporting.
I'm happy to change the approach if you think some other way is better.
Tomi
Add the two audio DMAs to the binding.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
---
.../devicetree/bindings/display/xlnx/xlnx,zynqmp-dpsub.yaml | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/Documentation/devicetree/bindings/display/xlnx/xlnx,zynqmp-dpsub.yaml b/Documentation/devicetree/bindings/display/xlnx/xlnx,zynqmp-dpsub.yaml
index 554f9d5809d4..6b754d4f260e 100644
--- a/Documentation/devicetree/bindings/display/xlnx/xlnx,zynqmp-dpsub.yaml
+++ b/Documentation/devicetree/bindings/display/xlnx/xlnx,zynqmp-dpsub.yaml
@@ -100,12 +100,16 @@ properties:
- description: Video layer, plane 1 (U/V or U)
- description: Video layer, plane 2 (V)
- description: Graphics layer
+ - description: Audio channel 0
+ - description: Audio channel 1
dma-names:
items:
- const: vid0
- const: vid1
- const: vid2
- const: gfx0
+ - const: aud0
+ - const: aud1
phys:
description: PHYs for the DP data lanes
@@ -194,11 +198,13 @@ examples:
power-domains = <&pd_dp>;
resets = <&reset ZYNQMP_RESET_DP>;
- dma-names = "vid0", "vid1", "vid2", "gfx0";
+ dma-names = "vid0", "vid1", "vid2", "gfx0", "aud0", "aud1";
dmas = <&xlnx_dpdma 0>,
<&xlnx_dpdma 1>,
<&xlnx_dpdma 2>,
- <&xlnx_dpdma 3>;
+ <&xlnx_dpdma 3>,
+ <&xlnx_dpdma 4>,
+ <&xlnx_dpdma 5>;
phys = <&psgtr 1 PHY_TYPE_DP 0 3>,
<&psgtr 0 PHY_TYPE_DP 1 3>;
--
2.34.1
