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From:   Emil Renner Berthing <kernel@esmil.dk>
Date:   Fri, 22 Oct 2021 15:34:58 +0200
Message-ID: <CANBLGcysKdqo+FioSkhd1PZRLzPF=fRJrCTsUGR7vXcn2WpYHg@mail.gmail.com>
Subject: Re: [PATCH v2 09/16] reset: starfive-jh7100: Add StarFive JH7100
 reset driver
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     linux-riscv <linux-riscv@lists.infradead.org>,
        devicetree <devicetree@vger.kernel.org>,
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        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        "open list:SERIAL DRIVERS" <linux-serial@vger.kernel.org>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Rob Herring <robh+dt@kernel.org>,
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        Stephen Boyd <sboyd@kernel.org>,
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        Linus Walleij <linus.walleij@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
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On Fri, 22 Oct 2021 at 14:56, Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> On Thu, Oct 21, 2021 at 8:43 PM Emil Renner Berthing <kernel@esmil.dk> wrote:
> > +static const u32 jh7100_reset_asserted[4] = {
>
> > +       BIT(JH7100_RST_U74 % 32) |
> > +       BIT(JH7100_RST_VP6_DRESET % 32) |
> > +       BIT(JH7100_RST_VP6_BRESET % 32),
>
> It's hard to notice that this is only one entry. See also below.

Yeah, so what would be a better way to style it?

> > +       BIT(JH7100_RST_HIFI4_DRESET % 32) |
> > +       BIT(JH7100_RST_HIFI4_BRESET % 32),
> > +
> > +       BIT(JH7100_RST_E24 % 32)
>
> + Comma.
>
> > +};
>
> Why all these ugly % 32 against constants?

Because the JH7100_RST_ values goes higher than 31. There is a
BIT_MASK macro, but that does % BITS_PER_LONG and this is a 64bit
machine.

> ...
>
> > +       if (!assert)
> > +               done ^= mask;
>
> Can you convert this to simple
>
>   if (assert)
>     ret = readl_...
>   else
>     ret = readl_...
>
> below?

I don't see how that would work. We're using the done value in in the
readl_poll_timeout. Maybe you can be a bit more explicit.

The reason is that for most reset lines a 0 in the status register
means it's asserted and a 1 means it's deasserted. For the few reset
lines above this is reversed though.

/Emil