diff mbox series

[v2,1/2] gpiolib: improve coding style for local variables

Message ID 20211118132317.15898-1-brgl@bgdev.pl
State Superseded
Headers show
Series [v2,1/2] gpiolib: improve coding style for local variables | expand

Commit Message

Bartosz Golaszewski Nov. 18, 2021, 1:23 p.m. UTC 
Drop unneeded whitespaces and put the variables of the same type
together for consistency with the rest of the code.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/gpio/gpiolib.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

Comments

Andy Shevchenko Nov. 22, 2021, 11:20 a.m. UTC | #1 
On Fri, Nov 19, 2021 at 08:35:33PM +0100, Bartosz Golaszewski wrote:
> On Thu, Nov 18, 2021 at 10:16 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > On Thu, Nov 18, 2021 at 09:12:59PM +0100, Bartosz Golaszewski wrote:
> > > On Thu, Nov 18, 2021 at 6:06 PM Andy Shevchenko
> > > <andriy.shevchenko@linux.intel.com> wrote:
> > > > On Thu, Nov 18, 2021 at 02:23:17PM +0100, Bartosz Golaszewski wrote:

...

> > > > >       if (gc->ngpio == 0) {
> > > > > -             chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> > > > > -             ret = -EINVAL;
> > > > > -             goto err_free_descs;
> > > > > +             ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
> > > > > +             if (ret) {
> > > > > +                     chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> > > > > +                     ret = -EINVAL;
> > > > > +                     goto err_free_descs;
> > > > > +             }
> > > > > +
> > > > > +             gc->ngpio = ngpios;
> > > > >       }
> > > >
> > > > This should be
> > > >
> > > >         if (gc->ngpio == 0) {
> > > >                 ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
> > > >                 if (ret)
> > > >                         return ret;
> > >
> > > But device_property_read_u32() returning -ENODATA means there's no
> > > such property, which should actually be converted to -EINVAL as the
> > > caller wanting to create the chip provided invalid configuration - in
> > > this case: a chip with 0 lines. In case of the non-array variant of
> > > read_u32 that's also the only error that can be returned so this bit
> > > looks right to me.
> >
> > So, what is so special about -EINVAL? Why -ENODATA is not good enough which
> > will exactly explain to the caller what's going on, no?
> >
> 
> Let's imagine the user sets gc->ngpio = 0 incorrectly thinking it'll
> make gpiolib set it to some sane default. Then gpiochip_add_data()
> returns -ENODATA (No data available). This is confusing IMO. But if we
> convert it to -EINVAL, it now says "Invalid value" which points to the
> wrong configuration.
> 
> ENODATA means "device tree property is not present" in this case but
> the problem is that user supplies the gpiolib with invalid
> configuration. EINVAL is the right error here.

Then be explicit, don't shadow other error codes from fwnode API.

	if (ret && ret != -ENODATA)

> > > >                 gc->ngpio = ngpios;
> > > >         }
> > > >
> > > >         if (gc->ngpio == 0) {
> > > >                 chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> > > >                 ret = -EINVAL;
> > > >                 goto err_free_descs;
> >
> > When the caller intended to create a chip with 0 GPIOs they will get an error
> > as you wish with an error message.
> 
> Yes, as it was before.
diff mbox series

Patch

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index abfbf546d159..20d63028b85c 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -594,11 +594,10 @@  int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 			       struct lock_class_key *request_key)
 {
 	struct fwnode_handle *fwnode = gc->parent ? dev_fwnode(gc->parent) : NULL;
-	unsigned long	flags;
-	int		ret = 0;
-	unsigned	i;
-	int		base = gc->base;
+	int ret = 0, base = gc->base;
 	struct gpio_device *gdev;
+	unsigned long flags;
+	unsigned int i;
 
 	/*
 	 * First: allocate and populate the internal stat container, and