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

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Date:   Thu, 29 Jun 2023 19:10:33 +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

Hello Andy!

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. 

> 
> Can you use fwnode_irq_get() instead?

Will it help ?

>From docs:

 * Return: Linux IRQ number on success. Other values are determined
 * according to acpi_irq_get() or of_irq_get() operation.

* of_irq_get()
* Return: Linux IRQ number on success, or 0 on the IRQ mapping failure


> The shadowing is most likely due to nasty =0 comparison.

Indeed.


> 
> Also that ERROR is a bit weird, pr_err() is already on error level.
> 

Completely agree.