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Date:   Tue, 22 Mar 2022 19:42:24 +0100
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Subject: Re: [Patch v5 3/4] dt-bindings: memory: Update reg maxitems for
 tegra186
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To:     Ashish Mhetre <amhetre@nvidia.com>, robh+dt@kernel.org,
        thierry.reding@gmail.com, digetx@gmail.com, jonathanh@nvidia.com,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        linux-tegra@vger.kernel.org
Cc:     vdumpa@nvidia.com, Snikam@nvidia.com
References: <20220316092525.4554-1-amhetre@nvidia.com>
 <20220316092525.4554-4-amhetre@nvidia.com>
 <74db8a20-7cce-ff86-7ae4-466416443ba9@canonical.com>
 <66a3f996-ac12-9165-93c9-e1fa93b80eed@nvidia.com>
From:   Krzysztof Kozlowski <krzk@kernel.org>
In-Reply-To: <66a3f996-ac12-9165-93c9-e1fa93b80eed@nvidia.com>
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On 22/03/2022 19:12, Ashish Mhetre wrote:
> 
> 
> On 3/20/2022 6:12 PM, Krzysztof Kozlowski wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> On 16/03/2022 10:25, Ashish Mhetre wrote:
>>>  From tegra186 onwards, memory controller support multiple channels.
>>> Reg items are updated with address and size of these channels.
>>> Tegra186 has overall 5 memory controller channels. Tegra194 and tegra234
>>> have overall 17 memory controller channels each.
>>> There is 1 reg item for memory controller stream-id registers.
>>> So update the reg maxItems to 18 in tegra186 devicetree documentation.
>>>
>>> Signed-off-by: Ashish Mhetre <amhetre@nvidia.com>
>>> ---
>>>   .../nvidia,tegra186-mc.yaml                   | 20 +++++++++++++------
>>>   1 file changed, 14 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra186-mc.yaml b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra186-mc.yaml
>>> index 13c4c82fd0d3..3c4e231dc1de 100644
>>> --- a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra186-mc.yaml
>>> +++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra186-mc.yaml
>>> @@ -34,8 +34,8 @@ properties:
>>>             - nvidia,tegra234-mc
>>>
>>>     reg:
>>> -    minItems: 1
>>> -    maxItems: 3
>>> +    minItems: 6
>>> +    maxItems: 18
>>
>> Still ABI break and now the in-kernel DTS will report dt check errors.
>>
> The dt check error is because I mistakenly updated example in EMC node
> instead of MC. I'll fix it in next version.

The existing DTS will start failing with:
nvidia,tegra186-mc.example.dtb: memory-controller@2c00000: reg: [[0,
46137344, 0, 720896]] is too short


because you require now length of 6 minimum.

> 
>> I think you ignored the comments you got about breaking ABI.
>>
> No, I took care of the ABI break in v5. I have updated details about
> how we took care of it in first patch.

Right, driver part looks ok.


Best regards,
Krzysztof