linux-kernel - Re: [PATCH v1 09/43] clocksource: ep93xx: Add driver for Cirrus Logic EP93xx

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Date:   Thu, 29 Jun 2023 20:16:13 +0300
From:   Nikita Shubin <nikita.shubin@...uefel.me>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Alexander Sverdlin <alexander.sverdlin@...il.com>,
        Arnd Bergmann <arnd@...db.de>,
        Linus Walleij <linus.walleij@...aro.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Michael Peters <mpeters@...eddedts.com>,
        Kris Bahnsen <kris@...eddedts.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 09/43] clocksource: ep93xx: Add driver for Cirrus
 Logic EP93xx

On Thu, 2023-06-29 at 16:39 +0300, Andy Shevchenko wrote:
> On Thu, Jun 29, 2023 at 4:10 PM Nikita Shubin
> <nikita.shubin@...uefel.me> wrote:
> > On Wed, 2023-06-21 at 11:28 +0300, Andy Shevchenko wrote:
> > > On Wed, Jun 21, 2023 at 11:22 AM Nikita Shubin
> > > <nikita.shubin@...uefel.me> wrote:
> 
> ...
> 
> > > > > > +       irq = irq_of_parse_and_map(np, 0);
> > > > > > +       if (irq <= 0) {
> > > > > > +               pr_err("ERROR: invalid interrupt
> > > > > > number\n");
> > > > > > +               ret = -EINVAL;
> > > > > 
> > > > > Shadowed error in case of negative returned code. Why?
> > > > 
> > > > Majority of clocksource drivers shadow it. Same like above.
> > > 
> > > It doesn't mean they are correct or using brand new APIs.
> > 
> > Or may be this because irq_of_parse_and_map can return zero as
> > error,
> > and returning zero from timer_init means success ?
> > 
> > Please correct me if i am wrong here.
> 
> 0 means no mapped IRQ.
> 
> > > Can you use fwnode_irq_get() instead?
> > 
> > Will it help ?
> 
> Yes, definitely, in two aspects:
> 1/ it makes code less OF-dependent (helps also OF people to clean up
> the spread of OF headers and APIs where they are not needed);
> 2/ it takes care about proper error codes.
> 

Well... every use of fwnode_irq_get in 6.4 looks like:

	err = fwnode_irq_get(fwnode, 0);
	if (err < 0)
		return err;
	if (!err)
		return -EINVAL;

So i don't see any special care as it still calls of_irq_get just like
irq_of_parse_and_map.

But i am convinced to use the same approach, thank you!