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Message-ID: <3c80282b-0d63-1e1f-1036-1c8e79f1cbbc@collabora.com>
Date:   Tue, 12 Apr 2022 01:28:41 +0300
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Subject: Re: [Patch v6 3/4] dt-bindings: memory: Update reg maxitems for
 tegra186
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To:     Ashish Mhetre <amhetre@nvidia.com>,
        Dmitry Osipenko <digetx@gmail.com>,
        krzysztof.kozlowski@linaro.org, thierry.reding@gmail.com,
        jonathanh@nvidia.com, robh+dt@kernel.org,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        linux-tegra@vger.kernel.org, krzysztof.kozlowski+dt@linaro.org
Cc:     vdumpa@nvidia.com, Snikam@nvidia.com
References: <20220406052459.10438-1-amhetre@nvidia.com>
 <20220406052459.10438-4-amhetre@nvidia.com>
 <3e044f9e-3200-bb26-897d-1977e3825c92@gmail.com>
 <81686bc4-c580-862b-1c29-51b34e419154@nvidia.com>
 <57825f4a-8cfa-ef00-6462-fea37cd4d7be@collabora.com>
 <8930bbfe-2c33-ea90-c48d-c6a00005b6a5@nvidia.com>
From:   Dmitry Osipenko <dmitry.osipenko@collabora.com>
In-Reply-To: <8930bbfe-2c33-ea90-c48d-c6a00005b6a5@nvidia.com>
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On 4/11/22 18:41, Ashish Mhetre wrote:
> 
> 
> On 4/11/2022 8:59 PM, Dmitry Osipenko wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> On 4/11/22 18:02, Ashish Mhetre wrote:
>>>
>>>
>>> On 4/10/2022 7:51 PM, Dmitry Osipenko wrote:
>>>> External email: Use caution opening links or attachments
>>>>
>>>>
>>>> 06.04.2022 08:24, Ashish Mhetre пишет:
>>>>>            memory-controller@2c00000 {
>>>>>                compatible = "nvidia,tegra186-mc";
>>>>> -            reg = <0x0 0x02c00000 0x0 0xb0000>;
>>>>> +            reg = <0x0 0x02c00000 0x0 0x10000>,    /* MC-SID */
>>>>> +                  <0x0 0x02c10000 0x0 0x10000>,    /* Broadcast
>>>>> channel */
>>>>> +                  <0x0 0x02c20000 0x0 0x10000>,    /* MC0 */
>>>>> +                  <0x0 0x02c30000 0x0 0x10000>,    /* MC1 */
>>>>> +                  <0x0 0x02c40000 0x0 0x10000>,    /* MC2 */
>>>>> +                  <0x0 0x02c50000 0x0 0x10000>;    /* MC3 */
>>>>> +            reg-names = "mc-sid", "mc-broadcast", "mc0", "mc1",
>>>>> "mc2", "mc3";
>>>>
>>>> The "mc-" prefix feels redundant to me, I'd name the regs like this:
>>>>
>>>>     "sid", "broadcast", "ch0", "ch1", "ch2", "ch3"
>>>>
>>>>
>>>> You should also add validation of the regs/reg-names to the yaml based
>>>> on SoC version. I.e. it's not enough to only bump the maxItems.
>>>
>>> Okay, I will add validation of reg-names as following:
>>>
>>>    reg-names:
>>>      minItems: 0
>>>      maxItems: 6
>>>      items:
>>>        - const: sid
>>>        - const: broadcast
>>>        - const: ch0
>>>        - const: ch1
>>>        - const: ch2
>>>        - const: ch3
>>>
>>>
>>> We will have to keep minItems to 0 in order to make it compatible with
>>> old DT, right?
>>
>> Bindings are about the latest DTs. In general older dtbs must be updated
>> and you must get error from the schema checker for older DTs. It's only
>> drivers that should care about older dtbs.
> 
> On v5 Krzysztof mentioned that old DTS will start failing with new
> bindings https://lkml.org/lkml/2022/3/22/907.
> So I just wanted to confirm whether it's fine if updated bindings
> start to fail with old DTS?

Since the older DT was incorrect, it's fine that the DT check will fail
for it.