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Date:   Sun, 23 Oct 2022 16:15:58 +0100
From:   Paul Cercueil <paul@crapouillou.net>
Subject: Re: [PATCH v3 2/2] serial: 8250/ingenic: Add support for the
 JZ4750/JZ4755
To:     Siarhei Volkau <lis8215@gmail.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Jiri Slaby <jirislaby@kernel.org>,
        linux-serial@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org
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Le dim. 23 oct. 2022 =C3=A0 17:04:49 +0300, Siarhei Volkau=20
<lis8215@gmail.com> a =C3=A9crit :
> =D0=B2=D1=81, 23 =D0=BE=D0=BA=D1=82. 2022 =D0=B3. =D0=B2 12:16, Paul Cerc=
ueil=20
> <paul@crapouillou.net>:
>>  Do you have such hardware?
>=20
> No
>=20
>>  Don't add support for cases you can't test.
>=20
> It's just a side effect of that approach.
>=20
>>  For what we know - all JZ475x use a 24 MHz crystal and all JZ4760(B)
>>  use a 12 MHz crystal, until proven otherwise.
>=20
> Ouf course it just confirms the rule but I found one exception:=20
> JZ4750 & 12MHz
> Link:=20
> https://github.com/carlos-wong/uboot_jz4755/blob/master/include/configs/l=
ib4750.h

Then when this board is upstreamed it will declare a 12 MHz oscillator=20
in its DT, and the ingenic init code won't have to enable the /2=20
divider for that particular board.

> Regarding your proposal:
> In my opinion enabling the divisor unconditionally is a bad practice,
> as it's already enabled (or not) by the bootloader, with respect to=20
> the
> hardware capabilities.I think it's better to keep the driver as it is=20
> than
> adding such things.

Well, I disagree. Linux should not depend on whatever the bootloader=20
configures.

-Paul