On Wed, Nov 3, 2021 at 5:34 AM Akhil R [off-list ref] wrote:

quoted

On Thu, Oct 28, 2021 at 06:53:36PM +0530, Akhil R wrote:

quoted

Add DT binding document for Nvidia Tegra GPCDMA controller.

Signed-off-by: Rajesh Gumasta <redacted>
Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
---
 .../bindings/dma/nvidia,tegra186-gpc-dma.yaml      | 115

+++++++++++++++++++++

quoted

 1 file changed, 115 insertions(+)
 create mode 100644
Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml

diff --git
a/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
b/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
new file mode 100644
index 0000000..bc97efc

--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.ya
+++ ml

@@ -0,0 +1,115 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2
+---
+$id: http://devicetree.org/schemas/dma/nvidia,tegra186-gpc-dma.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NVIDIA Tegra GPC DMA Controller Device Tree Bindings
+
+description: |
+  The Tegra General Purpose Central (GPC) DMA controller is used for
+faster
+  data transfers between memory to memory, memory to device and
+device to
+  memory.
+
+maintainers:
+  - Jon Hunter <jonathanh@nvidia.com>
+  - Rajesh Gumasta <rgumasta@nvidia.com>
+
+allOf:
+  - $ref: "dma-controller.yaml#"
+
+properties:
+  compatible:
+    oneOf:
+      - enum:
+          - nvidia,tegra186-gpcdma
+          - nvidia,tegra194-gpcdma
+      - items:
+          - const: nvidia,tegra186-gpcdma
+          - const: nvidia,tegra194-gpcdma

One of these is wrong. Either 186 has a fallback to 194 or it doesn't.

Not sure if I understood this correctly. Tegra186 and 194 have different chip data
inside driver based on the compatible. I guess, it then needs to be one of these.
Or is the mistake something related to formatting?

It's not about what the driver uses, but what is valid in a DT file.
Either you say the 2 implementations are different and in no way
compatible with each other:

enum:
  - nvidia,tegra186-gpcdma
  - nvidia,tegra194-gpcdma

Or you say 186 is backwards compatible with 194 (meaning 186 is a
superset of 194 so a driver written for 194 still works on 186 (though
not any new features)).

oneOf:
  - const: nvidia,tegra194-gpcdma
  - items:
    - const: nvidia,tegra186-gpcdma
    - const: nvidia,tegra194-gpcdma

Rob