Re: [PATCH v1 12/16] pinctrl: starfive: Add pinctrl driver for StarFive SoCs

From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Emil Renner Berthing <kernel@esmil.dk>
Cc: linux-riscv <linux-riscv@lists.infradead.org>,
	devicetree <devicetree@vger.kernel.org>,
	linux-clk <linux-clk@vger.kernel.org>,
	"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>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Marc Zyngier <maz@kernel.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Linus Walleij <linus.walleij@linaro.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Jiri Slaby <jirislaby@kernel.org>,
	Maximilian Luz <luzmaximilian@gmail.com>,
	Sagar Kadam <sagar.kadam@sifive.com>,
	Drew Fustini <drew@beagleboard.org>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Anup Patel <anup.patel@wdc.com>,
	Atish Patra <atish.patra@wdc.com>,
	Matteo Croce <mcroce@microsoft.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Huan Feng <huan.feng@starfivetech.com>
Subject: Re: [PATCH v1 12/16] pinctrl: starfive: Add pinctrl driver for StarFive SoCs
Date: Mon, 18 Oct 2021 19:28:10 +0300	[thread overview]
Message-ID: <CAHp75VcgFRGpca-pSU9T5Oo1fT4aWQJd5EQfyZscGYx0mDMJ_Q@mail.gmail.com> (raw)
In-Reply-To: <CAHp75VccSDLVbs1sF_-1zghWyLKtKKV1qtxOxZZ-cS0e6S-sBA@mail.gmail.com>

On Mon, Oct 18, 2021 at 7:23 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Mon, Oct 18, 2021 at 6:56 PM Emil Renner Berthing <kernel@esmil.dk> wrote:
> > On Mon, 18 Oct 2021 at 17:48, Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > > On Mon, Oct 18, 2021 at 6:35 PM Emil Renner Berthing <kernel@esmil.dk> wrote:
> > > > On Tue, 12 Oct 2021 at 19:03, Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > > > > On Tue, Oct 12, 2021 at 4:43 PM Emil Renner Berthing <kernel@esmil.dk> wrote:

...

> > > > > > +       ret = clk_prepare_enable(clk);
> > > > > > +       if (ret) {
> > > > >
> > > > > > +               reset_control_deassert(rst);
> > > > >
> > > > > Use devm_add_action_or_reset().
> > > >
> > > > I don't see how that is better.
> > >
> > > Pity. The rule of thumb is to either try to use devm_*() everywhere in
> > > the probe, or don't use it at all. Above is the more-or-less standard
> > > pattern where devn_add_action_or_reset() is being used in the entire
> > > kernel.
> > >
> > > > Then I'd first need to call that and
> > > > check for errors, but just on the line below enabling the clock the
> > > > reset line is deasserted anyway, so then the action isn't needed any
> > > > longer. So that 3 lines of code for devm_add_action_or_reset +
> > > > lingering unneeded action or code to remove it again vs. just the line
> > > > above.
> > >
> > > Then don't use devm_*() at all. What's the point?
> >
> > I'm confused. So you wan't an unneeded action to linger because the
> > probe function temporarily asserts reset for 3 lines of code?
>
> I;m talking about clk_prepare_enable().

Having a second look I found even problematic error paths because of
mixing devm_*() with non-devm_*() calls, which only assures me that
your ->probe() error path is broken and should be revisited.

-- 
With Best Regards,
Andy Shevchenko