linux-kernel - Re: [PATCH 2/2] gpio: bcm-kona: use platform_irq

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Message-ID: <20191203071534.zqxlizjkav4ul2n5@pengutronix.de>
Date:   Tue, 3 Dec 2019 08:15:34 +0100
From:   Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
To:     Peng Fan <peng.fan@....com>
Cc:     "rjui@...adcom.com" <rjui@...adcom.com>,
        "linus.walleij@...aro.org" <linus.walleij@...aro.org>,
        "bgolaszewski@...libre.com" <bgolaszewski@...libre.com>,
        "f.fainelli@...il.com" <f.fainelli@...il.com>,
        "sbranden@...adcom.com" <sbranden@...adcom.com>,
        "thierry.reding@...il.com" <thierry.reding@...il.com>,
        "robh@...nel.org" <robh@...nel.org>,
        "bcm-kernel-feedback-list@...adcom.com" 
        <bcm-kernel-feedback-list@...adcom.com>,
        dl-linux-imx <linux-imx@....com>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-pwm@...r.kernel.org" <linux-pwm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Alice Guo <alice.guo@....com>
Subject: Re: [PATCH 2/2] gpio: bcm-kona: use platform_irq_count

On Tue, Dec 03, 2019 at 07:00:40AM +0000, Peng Fan wrote:
> > Subject: Re: [PATCH 2/2] gpio: bcm-kona: use platform_irq_count
> > 
> > On Tue, Dec 03, 2019 at 06:04:27AM +0000, Peng Fan wrote:
> > > From: Peng Fan <peng.fan@....com>
> > >
> > > Use platform_irq_count to replace of_irq_count
> > >
> > > Signed-off-by: Peng Fan <peng.fan@....com>
> > > ---
> > >
> > > V1:
> > >  Code inspection, not tested
> > >
> > >  drivers/gpio/gpio-bcm-kona.c | 3 +--
> > >  1 file changed, 1 insertion(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/gpio/gpio-bcm-kona.c
> > > b/drivers/gpio/gpio-bcm-kona.c index 4122683eb1f9..c50721980a7c
> > 100644
> > > --- a/drivers/gpio/gpio-bcm-kona.c
> > > +++ b/drivers/gpio/gpio-bcm-kona.c
> > > @@ -19,7 +19,6 @@
> > >  #include <linux/io.h>
> > >  #include <linux/gpio/driver.h>
> > >  #include <linux/of_device.h>
> > > -#include <linux/of_irq.h>
> > >  #include <linux/init.h>
> > >  #include <linux/irqdomain.h>
> > >  #include <linux/irqchip/chained_irq.h> @@ -586,7 +585,7 @@ static int
> > > bcm_kona_gpio_probe(struct platform_device *pdev)
> > >
> > >  	kona_gpio->gpio_chip = template_chip;
> > >  	chip = &kona_gpio->gpio_chip;
> > > -	kona_gpio->num_bank = of_irq_count(dev->of_node);
> > > +	kona_gpio->num_bank = platform_irq_count(pdev);
> > 
> > of_irq_count returns 0 or a positive int while platform_irq_count might return
> > a negative error code. This needs handling. Also I wonder why
> > platform_irq_count() is better than of_irq_count() which would be good to
> > describe in the commit log.
> 
> Inspired from https://lkml.org/lkml/2015/11/18/466
> From Rob:
> "
> So I started looking at why you are using of_irq_count which drivers
> shouldn't need to. In patch 5 you use it to allocate memory to store
> the irq names, then use them here...
> "
> 
> Is this ok?

I would say something like:

	platform_irq_count() is the more generic way (independent of
	device trees) to determine the count of available interrupts. So
	use this instead.

	As platform_irq_count() might return an error code (which
	of_irq_count doesn't) some additional handling is necessary.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |