iio: accel: bmc150: Fix bma222 scale unit
authorStephan Gerhold <stephan@gerhold.net>
Fri, 11 Jun 2021 08:08:54 +0000 (10:08 +0200)
committerJonathan Cameron <Jonathan.Cameron@huawei.com>
Sun, 13 Jun 2021 16:00:17 +0000 (17:00 +0100)
According to sysfs-bus-iio documentation the unit for accelerometer
values after applying scale/offset should be m/s^2, not g, which explains
why the scale values for the other variants in bmc150-accel do not match
exactly the values given in the datasheet.

To get the correct values, we need to multiply the BMA222 scale values
by g = 9.80665 m/s^2.

Fixes: a1a210bf29a1 ("iio: accel: bmc150-accel: Add support for BMA222")
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20210611080903.14384-2-stephan@gerhold.net
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
drivers/iio/accel/bmc150-accel-core.c

index a3d08d7..a80ee0f 100644 (file)
@@ -1145,11 +1145,12 @@ static const struct bmc150_accel_chip_info bmc150_accel_chip_info_tbl[] = {
                /*
                 * The datasheet page 17 says:
                 * 15.6, 31.3, 62.5 and 125 mg per LSB.
+                * IIO unit is m/s^2 so multiply by g = 9.80665 m/s^2.
                 */
-               .scale_table = { {156000, BMC150_ACCEL_DEF_RANGE_2G},
-                                {313000, BMC150_ACCEL_DEF_RANGE_4G},
-                                {625000, BMC150_ACCEL_DEF_RANGE_8G},
-                                {1250000, BMC150_ACCEL_DEF_RANGE_16G} },
+               .scale_table = { {152984, BMC150_ACCEL_DEF_RANGE_2G},
+                                {306948, BMC150_ACCEL_DEF_RANGE_4G},
+                                {612916, BMC150_ACCEL_DEF_RANGE_8G},
+                                {1225831, BMC150_ACCEL_DEF_RANGE_16G} },
        },
        [bma222e] = {
                .name = "BMA222E",