Re: [PATCH] input: (gtco) use sign_extend32() for sign extension

[Dmitry Torokhov]

On Fri, Jan 23, 2015 at 01:29:36PM +0100, Martin Kepplinger wrote:
> Signed-off-by: Martin Kepplinger <martink@xxxxxxxxx>
> ---
> Despite it's name, sign_extend32() is safe to use for 8 and 16 bit types too.


Applied, thank you, but I am sure it can be cleaned up even more.

> 
> 
>  drivers/input/tablet/gtco.c | 11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/input/tablet/gtco.c b/drivers/input/tablet/gtco.c
> index 8580456..272a838 100644
> --- a/drivers/input/tablet/gtco.c
> +++ b/drivers/input/tablet/gtco.c
> @@ -59,7 +59,7 @@ Scott Hill shill@xxxxxxxxxxxxxxx
>  #include <asm/uaccess.h>
>  #include <asm/unaligned.h>
>  #include <asm/byteorder.h>
> -
> +#include <linux/bitops.h>
>  
>  #include <linux/usb/input.h>
>  
> @@ -666,13 +666,8 @@ static void gtco_urb_callback(struct urb *urbinfo)
>  		case 4:
>  			/* Tilt */
>  
> -			/* Sign extend these 7 bit numbers.  */
> -			if (device->buffer[6] & 0x40)
> -				device->buffer[6] |= 0x80;
> -
> -			if (device->buffer[7] & 0x40)
> -				device->buffer[7] |= 0x80;
> -
> +			device->buffer[6] = sign_extend32(device->buffer[6], 6);
> +			device->buffer[7] = sign_extend32(device->buffer[7], 6);
>  
>  			valsigned = (device->buffer[6]);
>  			input_report_abs(inputdev, ABS_TILT_X, (s32)valsigned);
> -- 
> 2.1.4
> 

-- 
Dmitry
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