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Message-ID: <72ed9df4-4bec-b9e5-c14d-3e998d83a102@linaro.org>
Date:   Fri, 9 Sep 2022 14:57:06 +0200
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Subject: Re: [PATCH 1/3] dt-bindings: pwm: tegra: Add compatible string for
 Tegra234
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To:     Sandipan Patra <spatra@nvidia.com>,
        "thierry.reding@gmail.com" <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "krzysztof.kozlowski+dt@linaro.org" 
        <krzysztof.kozlowski+dt@linaro.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc:     Bibek Basu <bbasu@nvidia.com>,
        Krishna Yarlagadda <kyarlagadda@nvidia.com>
References: <20220907062545.30203-1-spatra@nvidia.com>
 <75d5e29e-7418-3b8f-f549-6a69fd479852@linaro.org>
 <DM5PR12MB16283364646CBD853C89B425AD439@DM5PR12MB1628.namprd12.prod.outlook.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <DM5PR12MB16283364646CBD853C89B425AD439@DM5PR12MB1628.namprd12.prod.outlook.com>
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On 09/09/2022 13:17, Sandipan Patra wrote:
> 
>> -----Original Message-----
>> From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>> Sent: Thursday, September 8, 2022 5:44 PM
>> To: Sandipan Patra <spatra@nvidia.com>; thierry.reding@gmail.com;
>> Jonathan Hunter <jonathanh@nvidia.com>; robh+dt@kernel.org;
>> krzysztof.kozlowski+dt@linaro.org; devicetree@vger.kernel.org; linux-
>> tegra@vger.kernel.org; linux-kernel@vger.kernel.org
>> Cc: Bibek Basu <bbasu@nvidia.com>; Krishna Yarlagadda
>> <kyarlagadda@nvidia.com>
>> Subject: Re: [PATCH 1/3] dt-bindings: pwm: tegra: Add compatible string for
>> Tegra234
>>
>> External email: Use caution opening links or attachments
>>
>>
>> On 07/09/2022 08:25, Sandipan Patra wrote:
>>> Tegra234 has 8 different PWM controllers and each controller has only
>>> one output. Add a device tree compatible string for Tegra234.
>>>
>>> Signed-off-by: Sandipan Patra <spatra@nvidia.com>
>>> ---
>>>  Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git
>>> a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt
>>> b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt
>>> index 74c41e34c3b6..331c1e66e8fa 100644
>>> --- a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt
>>> +++ b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt
>>> @@ -9,7 +9,7 @@ Required properties:
>>>    - "nvidia,tegra132-pwm", "nvidia,tegra20-pwm": for Tegra132
>>>    - "nvidia,tegra210-pwm", "nvidia,tegra20-pwm": for Tegra210
>>>    - "nvidia,tegra186-pwm": for Tegra186
>>> -  - "nvidia,tegra194-pwm": for Tegra194
>>> +  - "nvidia,tegra194-pwm": for Tegra194, Tegra234
>>
>> The commit msg suggest it is different. Are you sure they are exactly the
>> same? If not the same, but compatible, you should use fallback.
> 
> Tegra194 and Tegra234 are 2 different chips using exactly same pwm module and dt node.
> This change is to convey that same compatible is used for Tegra234 as well.

Then recommended is to have Tegra234 specific compatible with fallback
to 194.


Best regards,
Krzysztof