diff options
Diffstat (limited to 'drivers/iio/magnetometer/ak8975.c')
| -rw-r--r-- | drivers/iio/magnetometer/ak8975.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c index ff284e5afd9..05423543f89 100644 --- a/drivers/iio/magnetometer/ak8975.c +++ b/drivers/iio/magnetometer/ak8975.c @@ -85,6 +85,7 @@ #define AK8975_MAX_CONVERSION_TIMEOUT 500 #define AK8975_CONVERSION_DONE_POLL_TIME 10 #define AK8975_DATA_READY_TIMEOUT ((100*HZ)/1000) +#define RAW_TO_GAUSS(asa) ((((asa) + 128) * 3000) / 256) /* * Per-instance context data for the device. @@ -265,15 +266,15 @@ static int ak8975_setup(struct i2c_client *client) * * Since 1uT = 0.01 gauss, our final scale factor becomes: * - * Hadj = H * ((ASA + 128) / 256) * 3/10 * 100 - * Hadj = H * ((ASA + 128) * 30 / 256 + * Hadj = H * ((ASA + 128) / 256) * 3/10 * 1/100 + * Hadj = H * ((ASA + 128) * 0.003) / 256 * * Since ASA doesn't change, we cache the resultant scale factor into the * device context in ak8975_setup(). */ - data->raw_to_gauss[0] = ((data->asa[0] + 128) * 30) >> 8; - data->raw_to_gauss[1] = ((data->asa[1] + 128) * 30) >> 8; - data->raw_to_gauss[2] = ((data->asa[2] + 128) * 30) >> 8; + data->raw_to_gauss[0] = RAW_TO_GAUSS(data->asa[0]); + data->raw_to_gauss[1] = RAW_TO_GAUSS(data->asa[1]); + data->raw_to_gauss[2] = RAW_TO_GAUSS(data->asa[2]); return 0; } @@ -428,8 +429,9 @@ static int ak8975_read_raw(struct iio_dev *indio_dev, case IIO_CHAN_INFO_RAW: return ak8975_read_axis(indio_dev, chan->address, val); case IIO_CHAN_INFO_SCALE: - *val = data->raw_to_gauss[chan->address]; - return IIO_VAL_INT; + *val = 0; + *val2 = data->raw_to_gauss[chan->address]; + return IIO_VAL_INT_PLUS_MICRO; } return -EINVAL; } |