linux-kernel - Re: [PATCH] gpio: bd70528: remove unneeded break

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Message-ID: <0738b0cc482cfd07400cf8b0b0b2092e671cfb34.camel@fi.rohmeurope.com>
Date:   Tue, 20 Oct 2020 11:48:29 +0000
From:   "Vaittinen, Matti" <Matti.Vaittinen@...rohmeurope.com>
To:     "bgolaszewski@...libre.com" <bgolaszewski@...libre.com>,
        "trix@...hat.com" <trix@...hat.com>,
        "linus.walleij@...aro.org" <linus.walleij@...aro.org>
CC:     "joe@...ches.com" <joe@...ches.com>,
        linux-power <linux-power@...rohmeurope.com>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "apw@...onical.com" <apw@...onical.com>
Subject: Re: [PATCH] gpio: bd70528: remove unneeded break

On Tue, 2020-10-20 at 13:07 +0300, Matti Vaittinen wrote:
> Thanks Tom,
> 
> On Mon, 2020-10-19 at 12:33 -0700, trix@...hat.com wrote:
> > From: Tom Rix <trix@...hat.com>
> > 
> > A break is not needed if it is preceded by a return
> > 
> > Signed-off-by: Tom Rix <trix@...hat.com>
> > ---
> >  drivers/gpio/gpio-bd70528.c | 3 ---
> >  1 file changed, 3 deletions(-)
> > 
> > diff --git a/drivers/gpio/gpio-bd70528.c b/drivers/gpio/gpio-
> > bd70528.c
> > index 45b3da8da336..931e5765fe92 100644
> > --- a/drivers/gpio/gpio-bd70528.c
> > +++ b/drivers/gpio/gpio-bd70528.c
> > @@ -71,17 +71,14 @@ static int bd70528_gpio_set_config(struct
> > gpio_chip *chip, unsigned int offset,
> >  					  GPIO_OUT_REG(offset),
> >  					  BD70528_GPIO_DRIVE_MASK,
> >  					  BD70528_GPIO_OPEN_DRAIN);
> > -		break;
> My personal taste is also to omit these breaks but I am pretty sure I
> saw some tooling issuing a warning about falling through the switch-
> case back when I wrote this. Most probably checkpatch didn't like
> that
> back then.

I did a test and removed the breaks. Then I copied the modified file to
drivers/gpio/dummy.c
Next I committed this dummy.c in git, ran git-format-patch -s and
finally ran the checkpatch on this... Following was produced:


[mvaittin@...alhost linux]$ scripts/checkpatch.pl 0001-gpio-add-
dummy.patch 
Traceback (most recent call last):
  File "scripts/spdxcheck.py", line 6, in <module>
    from ply import lex, yacc
ImportError: No module named ply
WARNING: added, moved or deleted file(s), does MAINTAINERS need
updating?
#15: 
new file mode 100644

WARNING: Possible switch case/default not preceded by break or
fallthrough comment
#91: FILE: drivers/gpio/dummy.c:72:
+	case PIN_CONFIG_DRIVE_PUSH_PULL:

WARNING: Possible switch case/default not preceded by break or
fallthrough comment
#96: FILE: drivers/gpio/dummy.c:77:
+	case PIN_CONFIG_INPUT_DEBOUNCE:

total: 0 errors, 3 warnings, 229 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-
inplace.

0001-gpio-add-dummy.patch has style problems, please review.

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.

I guess that explains the odd "fallthrough" comments you mentioned in
another email. I guess the checkpatch should be fixed before you put
too much effort in clean-up...


And for peeps who have not been following - following function triggers
the checkpatch error above:

static int bd70528_gpio_set_config(struct gpio_chip *chip, unsigned int
offset,
				   unsigned long config)
{
	struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);

	switch (pinconf_to_config_param(config)) {
	case PIN_CONFIG_DRIVE_OPEN_DRAIN:
		return regmap_update_bits(bdgpio->chip.regmap,
					  GPIO_OUT_REG(offset),
					  BD70528_GPIO_DRIVE_MASK,
					  BD70528_GPIO_OPEN_DRAIN);
	case PIN_CONFIG_DRIVE_PUSH_PULL:
		return regmap_update_bits(bdgpio->chip.regmap,
					  GPIO_OUT_REG(offset),
					  BD70528_GPIO_DRIVE_MASK,
					  BD70528_GPIO_PUSH_PULL);
	case PIN_CONFIG_INPUT_DEBOUNCE:
		return bd70528_set_debounce(bdgpio, offset,
					    pinconf_to_config_argument(
config));
	default:
		break;
	}
	return -ENOTSUPP;
}


Best Regards
	Matti Vaittinen