Messages in this thread | | | Date | Mon, 22 Aug 2022 09:28:05 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH v2 16/16] hwmon: (mr75203) add debugfs to read and write temperature coefficients |
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On Mon, Aug 22, 2022 at 04:59:43PM +0300, Farber, Eliav wrote: > On 8/19/2022 2:11 AM, Guenter Roeck wrote: > > On Wed, Aug 17, 2022 at 05:43:21AM +0000, Eliav Farber wrote: > > > This change adds debugfs to read and write TS coefficients - g, h, j and > > > cal5. > > > > > > The coefficients can vary between product and product, so to calibrate > > > them it can be very useful to to be able to modify them on the fly. > > > > > > e.g. > > > > > > cat /sys/kernel/debug/940f23d0000.pvt/ts_coeff_cal5 > > > 4096 > > > > > > echo 83000 > sys/kernel/debug/940f23d0000.pvt/ts_coeff_g > > > > > > > What happens if you write 0 into all those attributes, or 0xffffffff ? > The driver equation is: > T = G + H * (n / cal5 - 0.5) + J * F > So I added protection for cal5 not being 0. > Besides that there is no limitation on what these values can be. > I can't really think of any other logical limitation I can apply. > There needs to be an overflow protection. I am quite sure that 0xffffffff would result in overflows and thus in quite random reported values.
Thanks, Guenter
> -- > Regards, Eliav
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