Re: [PATCH v8 5/8] Loongson: YeeLoong: add hardware monitoring driver

[Wu Zhangjin <wuzhangjin@gmail.com>]

On Sun, 2009-12-06 at 09:47 +0100, Pavel Machek wrote: 
> Hi!
> 
> > +static int get_battery_current(void)
> > +{
> > +   s16 value;
> > +
> > +   value = (ec_read(REG_BAT_CURRENT_HIGH) << 8) |
> > +           (ec_read(REG_BAT_CURRENT_LOW));
> > +
> > +   if (value < 0)
> > +           value = ~value + 1;
> > +
> > +   return value;
> > +}
> 
> What is going on here? I thought the value is already in two's
> complement... Is the above equivalent of
> 
>             if (value < 0)
>                value = -value; 
> 
> ? If so, why? If not, can you add a comment?

Right, then, will use this instead:

static int get_battery_current(void)
{ 
        s16 value;

        value = (ec_read(REG_BAT_CURRENT_HIGH) << 8) |
                (ec_read(REG_BAT_CURRENT_LOW));

        return abs(value);
}

Thanks & Best Regards,
        Wu Zhangjin