Re: [PATCH v1 1/1] gpio: pca953x: enfore type for i2c_smbus_write_word_data()

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Wed, 2016-06-01 at 23:19 +0800, Yong Li wrote:
> Hi andy,
> 
> Sorry for the confusing. I tested the patch today, using Ubuntu 1604 +
> gcc 5.3, the make bzImage does not output any warning messages about
> this .c file. I am wondering how you captured the warnings. It seems
> that I need the "make C=2" command.


It requires to explicitly enable endianess check via CF= parameter.

Linus, by the way do we need to go with this to stable and -rc2?

> 
> Thanks,
> Yong
> 
> 2016-06-01 20:35 GMT+08:00 Andy Shevchenko <andriy.shevchenko@linux.in
> tel.com>:
> > On Wed, 2016-06-01 at 12:44 +0800, Yong Li wrote:
> > > Hi Andy,
> > > 
> > > Could you let me know which build system you are using? I am using
> > > Ubuntu 1604(64 bit) to build the kernel source, but I did not find
> > > the
> > > warning.
> > 
> > Hmm... I'm confused what exactly you are asking here. My host system
> > is
> > Debian unstable, kernel is built by it's own KBuild infrastructure.
> > 
> > I'm pretty sure you are talking about this:
> > 
> > https://lwn.net/Articles/205624/
> > 
> > > 
> > > Thanks,
> > > Yong
> > > 
> > > 2016-06-01 3:03 GMT+08:00 Andy Shevchenko <andriy.shevchenko@linux
> > > .int
> > > el.com>:
> > > > The commit 9b8e3ec34318 ("gpio: pca953x: Use correct u16 value
> > > > for
> > > > register
> > > > word write") fixed regression in pca953x_write_regs(). At the
> > > > same
> > > > time the
> > > > solution introduced a sparse warning:
> > > > 
> > > > drivers/gpio/gpio-pca953x.c:168:39: warning: incorrect type in
> > > > argument 3 (different base types)
> > > > drivers/gpio/gpio-pca953x.c:168:39:    expected unsigned short
> > > > [unsigned] [usertype] value
> > > > drivers/gpio/gpio-pca953x.c:168:39:    got restricted __le16
> > > > [usertype] <noident>
> > > > 
> > > > Fix the code by enforcing the type of
> > > > i2c_smbus_write_word_data()
> > > > parameter.
> > > > 
> > > > Cc: Yong Li <sdliyong@gmail.com>
> > > > Cc: Phil Reid <preid@electromag.com.au>
> > > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.co
> > > > m>
> > > > ---
> > > >  drivers/gpio/gpio-pca953x.c | 9 ++++++---
> > > >  1 file changed, 6 insertions(+), 3 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-
> > > > pca953x.c
> > > > index d8233be..21b21cd 100644
> > > > --- a/drivers/gpio/gpio-pca953x.c
> > > > +++ b/drivers/gpio/gpio-pca953x.c
> > > > @@ -163,10 +163,13 @@ static int pca953x_write_regs(struct
> > > > pca953x_chip *chip, int reg, u8 *val)
> > > >                                         NBANK(chip), val);
> > > >         } else {
> > > >                 switch (chip->chip_type) {
> > > > -               case PCA953X_TYPE:
> > > > -                       ret = i2c_smbus_write_word_data(chip-
> > > > > client,
> > > > -                           reg << 1,
> > > > cpu_to_le16(get_unaligned((u16
> > > > *)val)));
> > > > +               case PCA953X_TYPE: {
> > > > +                       __le16 word =
> > > > cpu_to_le16(get_unaligned((u16
> > > > *)val));
> > > > +
> > > > +                       ret = i2c_smbus_write_word_data(chip-
> > > > > client, reg << 1,
> > > > +                                                       (__force
> > > > u16)word);
> > > >                         break;
> > > > +               }
> > > >                 case PCA957X_TYPE:
> > > >                         ret = i2c_smbus_write_byte_data(chip-
> > > > > client, reg << 1,
> > > >                                                         val[0]);
> > > > --
> > > > 2.8.1
> > > > 
> > 
> > --
> > Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Intel Finland Oy

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
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