Subject: Re: [PATCH v13 1/4] dt-bindings: dmaengine: Add doc for tegra gpcdma
To:     Akhil R <akhilrajeev@nvidia.com>, Rob Herring <robh@kernel.org>
Cc:     "dan.j.williams@intel.com" <dan.j.williams@intel.com>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>,
        Krishna Yarlagadda <kyarlagadda@nvidia.com>,
        Laxman Dewangan <ldewangan@nvidia.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
        "p.zabel@pengutronix.de" <p.zabel@pengutronix.de>,
        Rajesh Gumasta <rgumasta@nvidia.com>,
        "thierry.reding@gmail.com" <thierry.reding@gmail.com>,
        "vkoul@kernel.org" <vkoul@kernel.org>
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 <1637573292-13214-2-git-send-email-akhilrajeev@nvidia.com>
 <YaOo/FHKQBAa93hd@robh.at.kernel.org>
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From:   Jon Hunter <jonathanh@nvidia.com>
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Date:   Tue, 30 Nov 2021 09:34:19 +0000
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On 29/11/2021 05:01, Akhil R wrote:
>> On Mon, Nov 22, 2021 at 02:58:09PM +0530, Akhil R wrote:
>>> Add DT binding document for Nvidia Tegra GPCDMA controller.
>>>
>>> Signed-off-by: Rajesh Gumasta <rgumasta@nvidia.com>
>>> Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
>>> Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
>>> ---
>>>   .../bindings/dma/nvidia,tegra186-gpc-dma.yaml      | 111
>> +++++++++++++++++++++
>>>   1 file changed, 111 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..3a5a70d
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.ya
>>> +++ ml
>>> @@ -0,0 +1,111 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2
>>> +---
>>> +$id: https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevicetree.org%2Fschemas%2Fdma%2Fnvidia%2Ctegra186-gpc-dma.yaml%23&amp;data=04%7C01%7Cjonathanh%40nvidia.com%7Cd1e0c14ac72b4c24976908d9b2f53fb1%7C43083d15727340c1b7db39efd9ccc17a%7C0%7C0%7C637737588681303734%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=6qMb%2B0Lr3PMMvh5WrdTUEXC76qYo5rJKnG8DisYI5js%3D&amp;reserved=0
>>> +$schema: https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevicetree.org%2Fmeta-schemas%2Fcore.yaml%23&amp;data=04%7C01%7Cjonathanh%40nvidia.com%7Cd1e0c14ac72b4c24976908d9b2f53fb1%7C43083d15727340c1b7db39efd9ccc17a%7C0%7C0%7C637737588681303734%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=TktMUBi4U%2B%2B58D%2FJqGY4v9B78cYVMZeXP6pLM1CkGe0%3D&amp;reserved=0
>>> +
>>> +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:
>>> +      - const: nvidia,tegra186-gpcdma
>>> +      - items:
>>> +         - const: nvidia,tegra186-gpcdma
>>> +         - const: nvidia,tegra194-gpcdma
>>
>> Still not how 'compatible' works nor what I wrote out for you.
> I thought '186' and '194' got interchanged in your previous comment because it is 194
> which is the superset of 186 and have got more features than 186.
> Or probably I did not understand the idea correctly yet.


Hi Rob, this is the way around that we want it. Tegra194 is backward 
compatible with Tegra186. The above does align with what you mentioned 
before, so I am also not clear what the issue is with the above?

Jon

-- 
nvpublic