linux-kernel - Re: [PATCH v3 3/3] i2c: rk3x: Add check for clk

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Message-ID: <CANeGvZVibHOsqdD+zw_u2yswJdvUu=Ssep9eWeAOcqmg6J-zqg@mail.gmail.com>
Date: Thu, 14 Nov 2024 15:56:54 -0500
From: Jiasheng Jiang <jiashengjiangcool@...il.com>
To: Andi Shyti <andi.shyti@...nel.org>
Cc: dianders@...omium.org, rmk@...-67.arm.linux.org.uk, max.schwarz@...ine.de, 
	david.wu@...k-chips.com, heiko@...ech.de, vz@...ia.com, wsa@...nel.org, 
	manabian@...il.com, linux-arm-kernel@...ts.infradead.org, 
	linux-rockchip@...ts.infradead.org, linux-i2c@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 3/3] i2c: rk3x: Add check for clk_enable()

On Wed, Nov 13, 2024 at 5:24 PM Andi Shyti <andi.shyti@...nel.org> wrote:
>
> Hi Jiasheng,
>
> On Thu, Nov 07, 2024 at 09:14:28PM +0000, Jiasheng Jiang wrote:
> > Add check for the return value of clk_enable() in order to catch the
> > potential exception. Moreover, convert the return type of
>
> It's more an "unlikely exception" rather than a "potential
> exeption".
>
> > rk3x_i2c_adapt_div() into int and add the check.
>
> ...
>
> >  static u32 rk3x_i2c_func(struct i2c_adapter *adap)
> > @@ -1365,9 +1389,12 @@ static int rk3x_i2c_probe(struct platform_device *pdev)
> >       }
> >
> >       clk_rate = clk_get_rate(i2c->clk);
> > -     rk3x_i2c_adapt_div(i2c, clk_rate);
> > +     ret = rk3x_i2c_adapt_div(i2c, clk_rate);
> >       clk_disable(i2c->clk);
>
> you can't disable a clock that has failed to enable, right?
>
> BTW, although I like this patch (or at least I don't dislike), I
> still want to check whether it's wanted or not.
>
> Andi
>

Thank you for your advice. I have carefully reviewed the patch.
There are two clocks: "i2c->clk" and "i2c->pclk".
The "i2c->clk" is enabled and disabled in rk3x_i2c_probe(),
while the "i2c->pclk" is managed within rk3x_i2c_adapt_div().
Thus, the "i2c->clk" has already been enabled at this point.

-Jiasheng


> >
> > +     if (ret)
> > +             goto err_clk_notifier;
> > +
> >       ret = i2c_add_adapter(&i2c->adap);
> >       if (ret < 0)
> >               goto err_clk_notifier;
> > --
> > 2.25.1
> >