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

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Message-ID: <AM0PR04MB448149801572B13676845FF088420@AM0PR04MB4481.eurprd04.prod.outlook.com>
Date:   Tue, 3 Dec 2019 07:40:49 +0000
From:   Peng Fan <peng.fan@....com>
To:     Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
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

> Subject: Re: [PATCH 2/2] gpio: bcm-kona: use platform_irq_count
> 
> On Tue, Dec 03, 2019 at 07:23:14AM +0000, Peng Fan wrote:
> > > 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://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2F
> > > >
> lkml .org%2Flkml%2F2015%2F11%2F18%2F466&amp;data=02%7C01%7Cpen
> g.f
> > > an%40nxp.c
> > > >
> > >
> om%7C46364bf12479463df7d308d777c09b39%7C686ea1d3bc2b4c6fa92cd9
> > > 9c5c3016
> > > >
> > >
> 35%7C0%7C0%7C637109541440912984&amp;sdata=awTvwwmo4692Hx7IJ
> > > H%2BllEVJH7
> > > > ngINufoMH8UsosU%2BA%3D&amp;reserved=0
> > > > 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.
> >
> > Thanks, how about this change?
> > @@ -586,11 +585,15 @@ 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);
> > -       if (kona_gpio->num_bank == 0) {
> > +       ret = platform_irq_count(pdev);
> > +       if (!ret) {
> >                 dev_err(dev, "Couldn't determine # GPIO banks\n");
> >                 return -ENOENT;
> > +       } else if (ret < 0) {
> > +               return ret;
> 
> This is inconsitent. In the ret==0 case you emit an error message, in the ret <
> 0 case you don't. I think the sensible approach would be to
> do:
> 
> 	if (ret == 0) {
!ret should be fine, I think checkpatch might trigger warning using ret == 0.
> 		dev_err(dev, "Couldn't determine # GPIO banks\n");
> 		return -ENOENT;
> 	} else if (ret < 0) {
> 		if (ret != -EPROBE_DEFER)
> 			dev_err(dev, "Failed to determine count of GPIO banks
> (%pe)\n", ERR_PTR(ret));
> 		return ret;
> 	}

ok, will use this for v2.

Thanks,
Peng.

> 
> Best regards
> Uwe
> 
> --
> Pengutronix e.K.                           | Uwe Kleine-König
> |
> Industrial Linux Solutions                 |
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