Message-ID: <29db87ce-94b4-7106-aae6-a122c979d5d6@linaro.org>
Date:   Fri, 24 Feb 2023 09:26:47 +0100
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Subject: Re: [PATCH v1 RFC 1/3] dt-bindings: serial: amlogic,meson-uart: Add
 compatible string for G12A
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To:     Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc:     linux-amlogic@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        jirislaby@kernel.org, neil.armstrong@linaro.org,
        krzysztof.kozlowski+dt@linaro.org, robh+dt@kernel.org,
        gregkh@linuxfoundation.org,
        Christian Hewitt <christianshewitt@gmail.com>
References: <20230222210425.626474-1-martin.blumenstingl@googlemail.com>
 <20230222210425.626474-2-martin.blumenstingl@googlemail.com>
 <319cb654-51f6-6241-802b-22ee0d5b0aab@linaro.org>
 <CAFBinCCzXb2Ty3TaZatEKQyxJmYPhHDL7SeLfF5-3PsDKBznWw@mail.gmail.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <CAFBinCCzXb2Ty3TaZatEKQyxJmYPhHDL7SeLfF5-3PsDKBznWw@mail.gmail.com>
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On 23/02/2023 21:14, Martin Blumenstingl wrote:
> 
>> The question is whether the devices can be made compatible thus keeping
>> DTS working on older kernel. This commit suggests they are. Your DTS
>> commit is written in different tone - something was broken and is being
>> fixed.
> If we keep "amlogic,meson-gx-uart" as fallback compatible string then
> old kernels (or other .dtb consumers - like u-boot) would still work.
> Without the new "amlogic,meson-g12a-uart" compatible string we're
> unable to make use of a newly added clock divider within the UART IP
> block which allows baud rates such as 1500000 to work without (a lot
> of) jitter. Old kernels - with the new .dtb - would still be able to
> use serial (thanks to the "amlogic,meson-gx-uart" fallback compatible
> string) albeit with limited divider support (so not all baud rates can
> be used).
> Is this a valid plan?

Yes.

Best regards,
Krzysztof