Commit e2f82001 authored by Sean Nyekjaer's avatar Sean Nyekjaer Committed by Jonathan Cameron
Browse files

iio: imu: inv_icm42600: Fix temperature calculation 



>From the documentation:
"offset to be added to <type>[Y]_raw prior toscaling by <type>[Y]_scale"
Offset should be applied before multiplying scale, so divide offset by
scale to make this correct.

Fixes: bc3eb020 ("iio: imu: inv_icm42600: add temperature sensor support")
Signed-off-by: default avatarSean Nyekjaer <sean@geanix.com>
Acked-by: default avatarJean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Link: https://patch.msgid.link/20250502-imu-v1-1-129b8391a4e3@geanix.com


Cc: <Stable@vger.kernel.org>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 921fece3

drivers/iio/imu/inv_icm42600/inv_icm42600_temp.c

+5 −3
Original line number Diff line number Diff line
@@ -67,16 +67,18 @@ int inv_icm42600_temp_read_raw(struct iio_dev *indio_dev, 
		return IIO_VAL_INT;

	/*

	 * T°C = (temp / 132.48) + 25

	 * Tm°C = 1000 * ((temp * 100 / 13248) + 25)

	 * Tm°C = 1000 * ((temp / 132.48) + 25)

	 * Tm°C = 7.548309 * temp + 25000

	 * Tm°C = (temp + 3312) * 7.548309

	 * scale: 100000 / 13248 ~= 7.548309

	 * offset: 25000

	 * offset: 3312

	 */

	case IIO_CHAN_INFO_SCALE:

		*val = 7;

		*val2 = 548309;

		return IIO_VAL_INT_PLUS_MICRO;

	case IIO_CHAN_INFO_OFFSET:

		*val = 25000;

		*val = 3312;

		return IIO_VAL_INT;

	default:

		return -EINVAL;