Re: [PATCH v6] drm/i915/hwmon: expose fan speed

Andy Shevchenko
2024-08-22T13:28:30Z

On Thu, Aug 22, 2024 at 10:28:38AM +0300, Raag Jadav wrote:
> On Tue, Aug 20, 2024 at 05:06:39PM +0300, Andy Shevchenko wrote:
> > On Tue, Aug 20, 2024 at 04:12:46PM +0300, Raag Jadav wrote:
> > > On Tue, Aug 20, 2024 at 01:23:35PM +0300, Andy Shevchenko wrote:
> > > > On Tue, Aug 20, 2024 at 11:50:10AM +0530, Raag Jadav wrote:
> > > >
> > > > But it still has an issue with 64-bit division on 32-bit platforms, right?
> > > >
> > > > > + /*
> > > > > + * Calculate fan speed in RPM by time averaging two subsequent
> > > > > + * readings in minutes.
> > > > > + * RPM = number of rotations * msecs per minute / time in msecs
> > > > > + */
> > > > > + *val = DIV_ROUND_UP(rotations * (MSEC_PER_SEC * 60), time);
> > > >
> > > > ...somewhere here?
> > >
> > > Use div64_u64() instead? Or is there a better alternative?
> >
> > I don't know the code well to offer anything better. Probably for a starter
> > you can switch to use DIV_ROUND_UP_ULL().
>
> This one seems to work. Does it warrant an explanation here?

You mean _ULL part? No.

--
With Best Regards,
Andy Shevchenko