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| author | Ching-Kang Yen <chingkang@chromium.org> | 2020-07-30 17:37:08 +0800 |
|---|---|---|
| committer | Commit Bot <commit-bot@chromium.org> | 2020-09-03 07:15:38 +0000 |
| commit | 90c79d90699268d31a3a2d8f48af5955e493005b (patch) | |
| tree | d6b16ac11119d1fd117ef5279ddf40e27da6cc79 /driver/accelgyro_bmi_common.c | |
| parent | e9d86fc334f71d6f0daf44f9bc0f9ee311620095 (diff) | |
| download | chrome-ec-90c79d90699268d31a3a2d8f48af5955e493005b.tar.gz | |
driver: bmi: add get_rms_noise() for body detection
We will need the amount of noise for body detection.
The amount of noise in accelometer will depends on several thing, e.g.,
output data rate.
Add get_rms_noise() function to get the root mean square
of noise in BMI.
BRANCH=None
BUG=b:123434029
TEST=buildall
Signed-off-by: Ching-Kang Yen <chingkang@chromium.org>
Change-Id: Ia56bbd2cdb36bee771beb9df32451d3e56f4f028
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2329112
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Heng-ruey Hsu <henryhsu@chromium.org>
Diffstat (limited to 'driver/accelgyro_bmi_common.c')
| -rw-r--r-- | driver/accelgyro_bmi_common.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/driver/accelgyro_bmi_common.c b/driver/accelgyro_bmi_common.c index f348edb1c5..2d8cfa2c45 100644 --- a/driver/accelgyro_bmi_common.c +++ b/driver/accelgyro_bmi_common.c @@ -661,6 +661,34 @@ int bmi_get_offset(const struct motion_sensor_t *s, return EC_SUCCESS; } +#ifdef CONFIG_BODY_DETECTION +int bmi_get_rms_noise(const struct motion_sensor_t *s) +{ + int ret; + fp_t noise_100hz, rate, sqrt_rate_ratio; + + switch (s->type) { + case MOTIONSENSE_TYPE_ACCEL: + /* change unit of ODR to Hz to prevent INT_TO_FP() overflow */ + rate = INT_TO_FP(bmi_get_data_rate(s) / 1000); + /* + * Since the noise is proportional to sqrt(ODR) in BMI, and we + * have rms noise in 100 Hz, we multiply it with the sqrt(ratio + * of ODR to 100Hz) to get current noise. + */ + noise_100hz = INT_TO_FP(BMI_ACCEL_RMS_NOISE_100HZ(V(s))); + sqrt_rate_ratio = fp_sqrtf(fp_div(rate, + INT_TO_FP(BMI_ACCEL_100HZ))); + ret = FP_TO_INT(fp_mul(noise_100hz, sqrt_rate_ratio)); + break; + default: + CPRINTS("%s with gyro/mag is not implemented", __func__); + return 0; + } + return ret; +} +#endif + int bmi_get_resolution(const struct motion_sensor_t *s) { return BMI_RESOLUTION; |