iio: cros_ec: Fix the maths for gyro scale calculation
commit 3d02d7082e5823598090530c3988a35f69689943 upstream. Calculation did not use IIO_DEGREE_TO_RAD and implemented a variant to avoid precision loss as we aim a nano value. The offset added to avoid rounding error, though, doesn't give us a close result to the expected value. E.g. For 1000dps, the result should be: (1000 * pi ) / 180 >> 15 ~= 0.000532632218 But with current calculation we get $ cat scale 0.000547890 Fix the calculation by just doing the maths involved for a nano value val * pi * 10e12 / (180 * 2^15) so we get a closer result. $ cat scale 0.000532632 Fixes: c14dca07 ("iio: cros_ec_sensors: add ChromeOS EC Contiguous Sensors driver") Signed-off-by: NGwendal Grignou <gwendal@chromium.org> Signed-off-by: NEnric Balletbo i Serra <enric.balletbo@collabora.com> Cc: <Stable@vger.kernel.org> Signed-off-by: NJonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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