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

[Yong Li <sdliyong@xxxxxxxxx>]

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.

Thanks,
Yong

2016-06-01 20:35 GMT+08:00 Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>:
> 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@xxxxxxxxx
>> 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@xxxxxxxxx>
>> > Cc: Phil Reid <preid@xxxxxxxxxxxxxxxxx>
>> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
>> > ---
>> >  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@xxxxxxxxxxxxxxx>
> Intel Finland Oy
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