From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yong Li <sdliyong@gmail.com>
Subject: Re: [PATCH v1 1/1] gpio: pca953x: enfore type for i2c_smbus_write_word_data()
Date: Wed, 1 Jun 2016 12:44:53 +0800
Message-ID: <CADO9-pd60y8u7fQ-thBfpKr58t-=i2D9gyW-PWcz1_CyvgOFsA@mail.gmail.com>
References: <1464721423-10969-1-git-send-email-andriy.shevchenko@linux.intel.com>
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To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: linux-gpio@vger.kernel.org, Linus Walleij <linus.walleij@linaro.org>, Phil Reid <preid@electromag.com.au>

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.

Thanks,
Yong

2016-06-01 3:03 GMT+08:00 Andy Shevchenko <andriy.shevchenko@linux.intel.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.com>
> ---
>  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
>