Re: [PATCH 2/5] power: supply: bd71828: Fix current direction

On Wed, Aug 12, 2026 at 10:25:36AM +0200, Andreas Kemnade wrote:
> On Wed, 12 Aug 2026 11:17:36 +0300
> Andy Shevchenko <[email protected]> wrote:
> > On Wed, Aug 12, 2026 at 10:10:50AM +0200, Andreas Kemnade wrote:
> > > On Mon, 10 Aug 2026 13:09:07 +0300
> > > Matti Vaittinen <[email protected]> wrote:  

...

> > > That code is complicated. What about a generic 16bit non_2complemented sign
> > > to 2-complemented sign function/macro. Such would have prevented the error
> > > in the first places. So &vals[i] = signbit_to_2complement(be16_to_cpu(tmp_curr), 15) * pwr->curr_factor  
> > 
> > Do you mean existing sign_extend32() from bitops.h?
> > 
> 
> I don't think it does what is needed. Here we have
> 
> 0000 0000 0000 0001 -> 1
> Usually we have
> 
> 1111 1111 1111 1111 -> -1
> 
> but here
> 
> 1000 0000 0000 0001 -> -1

I see, wouldn't this be then as simple as

	sign = $REGVAL & BIT(15 /* sign bit */);
	if (sign)
		$REGVAL = sign - $REGVAL;

> If I do understand things correctly. I not find something useful
> in bitops.h.

-- 
With Best Regards,
Andy Shevchenko