Re: [PATCH] HID: ft260: fix format type warning in ft260_word_show()

[Joe Perches]

On Sun, 2021-05-09 at 22:32 +0300, Michael Zaidman wrote:
> Fixes: 6a82582d9fa4 ("HID: ft260: add usb hid to i2c host bridge driver")
> 
> Fix warning reported by static analysis when built with W=1 for arm64 by
> clang version 13.0.0
> 
> > > drivers/hid/hid-ft260.c:794:44: warning: format specifies type 'short' but
>    the argument has type 'int' [-Wformat]
>            return scnprintf(buf, PAGE_SIZE, "%hi\n", le16_to_cpu(*field));
>                                              ~~~     ^~~~~~~~~~~~~~~~~~~
>                                              %i
>    include/linux/byteorder/generic.h:91:21: note: expanded from
>                                             macro 'le16_to_cpu'
>    #define le16_to_cpu __le16_to_cpu
>                        ^
>    include/uapi/linux/byteorder/big_endian.h:36:26: note: expanded from
>                                                     macro '__le16_to_cpu'
>    #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x))
>                             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/uapi/linux/swab.h:105:2: note: expanded from macro '__swab16'
>            (__builtin_constant_p((__u16)(x)) ?     \
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Signed-off-by: Michael Zaidman <michael.zaidman@xxxxxxxxx>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> ---
>  drivers/hid/hid-ft260.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c
> index 047aa85a7c83..38794a29599c 100644
> --- a/drivers/hid/hid-ft260.c
> +++ b/drivers/hid/hid-ft260.c
> @@ -791,7 +791,7 @@ static int ft260_word_show(struct hid_device *hdev, int id, u8 *cfg, int len,
>  	if (ret != len && ret >= 0)
>  		return -EIO;
>  
> 
> -	return scnprintf(buf, PAGE_SIZE, "%hi\n", le16_to_cpu(*field));
> +	return scnprintf(buf, PAGE_SIZE, "%d\n", le16_to_cpu(*field));
>  }

There are 2 of these so I wonder about the static analysis.
It's probably better to use sysfs_emit as well.
---
 drivers/hid/hid-ft260.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c
index 7a9ba984a75a..475641682fff 100644
--- a/drivers/hid/hid-ft260.c
+++ b/drivers/hid/hid-ft260.c
@@ -783,7 +783,7 @@ static int ft260_byte_show(struct hid_device *hdev, int id, u8 *cfg, int len,
 	if (ret != len && ret >= 0)
 		return -EIO;
 
-	return scnprintf(buf, PAGE_SIZE, "%hi\n", *field);
+	return sysfs_emit(buf, "%d\n", *field);
 }
 
 static int ft260_word_show(struct hid_device *hdev, int id, u8 *cfg, int len,
@@ -795,7 +795,7 @@ static int ft260_word_show(struct hid_device *hdev, int id, u8 *cfg, int len,
 	if (ret != len && ret >= 0)
 		return -EIO;
 
-	return scnprintf(buf, PAGE_SIZE, "%hi\n", le16_to_cpu(*field));
+	return sysfs_emit(buf, "%d\n", le16_to_cpu(*field));
 }
 
 #define FT260_ATTR_SHOW(name, reptype, id, type, func)			       \