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Commit ce5b8fc1 authored by Gregor Boirie's avatar Gregor Boirie Committed by Jonathan Cameron
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iio:pressure:ms5611: fix ms5607 temp compensation 

Computation of sens2 was wrong and is fixed by this patch, sens2 should be:
    2 * (t - 2000)^2
See page 8 of ms5607 datasheet here:
    http://www.meas-spec.com/product/pressure/MS5607-02BA03.aspx



Signed-off-by: default avatarGregor Boirie <gregor.boirie@parrot.com>
Acked-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
Acked-by: default avatarPeter Meerwald-Stadler <pmeerw@pmeerw.net>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent fc0dccdd

drivers/iio/pressure/ms5611_core.c

+6 −6
Original line number Diff line number Diff line
@@ -136,17 +136,17 @@ static int ms5607_temp_and_pressure_compensate(struct ms5611_chip_info *chip_inf 


	t = 2000 + ((chip_info->prom[6] * dt) >> 23);

	if (t < 2000) {

		s64 off2, sens2, t2;

		s64 off2, sens2, t2, tmp;



		t2 = (dt * dt) >> 31;

		off2 = (61 * (t - 2000) * (t - 2000)) >> 4;

		sens2 = off2 << 1;

		tmp = (t - 2000) * (t - 2000);

		off2 = (61 * tmp) >> 4;

		sens2 = tmp << 1;



		if (t < -1500) {

			s64 tmp = (t + 1500) * (t + 1500);



			tmp = (t + 1500) * (t + 1500);

			off2 += 15 * tmp;

			sens2 += (8 * tmp);

			sens2 += 8 * tmp;

		}



		t -= t2;