On Tue, 29 Apr 2025 11:07:04 +0200
Paolo Abeni <pabeni@xxxxxxxxxx> wrote:
> On 4/22/25 4:56 PM, Kory Maincent wrote:
> > +/* Convert interrupt events to 0xff to be aligned with the chan
> > + * number.
> > + */
> > +static u8 tps23881_irq_export_chans_helper(u16 reg_val, u8 field_offset)
> > +{
> > + u8 val;
> > +
> > + val = (reg_val >> (4 + field_offset) & 0xf0) |
> > + (reg_val >> field_offset & 0x0f);
>
> I'm probably low on coffee but I don't see why the above could not be
> replaced with:
>
> return reg_val >> field_offset;
>
> (given that the return type is u8)
Shift takes precedence to bit operation.
So the calculation is like:
val = ((reg_val >> (4 + field_offset)) & 0xf0) |
((reg_val >> field_offset) & 0x0f)
Supposing reg_val = 0xabcd;
- If field_offset = 0, we return 0xbd;
- If field_offset = 4, we return 0xac
Regards
--
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com
