• Rasmus Villemoes's avatar
    hwmon: (ad7314) Do proper sign extension · 984faa1f
    Rasmus Villemoes authored
    The comment above (data << 2) >> 2 explains what the intention is: To
    use bit 13 of the 14-bit value data as the sign bit. However, this
    doesn't work due to C's promotion rules. data has type s16, but data
    << 2 has type int. To get sign extension, that expression would have
    to be cast back to an s16 before being shifted (at which point C's
    promotion rules would then kick in again and promote the left operand
    to int). As it stands, both expressions are no-ops for any value of
    data.
    
    Avoid these subtleties by using the existing API for
    this. sign_extend32 works equally well for 8 and 16 bit types.
    Signed-off-by: default avatarRasmus Villemoes <linux@rasmusvillemoes.dk>
    Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
    984faa1f
ad7314.c 3.76 KB