driver: bmi160: Fix ODR to REG when rate is less than 100Hz properly

When the ODr was the exact frequency, the calculation was not correct.
For instance, 50Hz would return register 6 when 7 was expected.

Fixes: 0e99e9763 ("bmi160: Fix ODR to REG when rate is less than 100Hz")

BUG=b:120942904
BRANCH=none
TEST=use:
    for (int i = 1600000 ; i > 1000 ; i >>= 1) {
        printf("%d mHZ : reg %d\n", i + 1, BMI160_ODR_TO_REG(i + 1));
        printf("%d mHZ : reg %d\n", i, BMI160_ODR_TO_REG(i));
        printf("%d mHZ : reg %d\n", i -1 , BMI160_ODR_TO_REG(i -1));
    }
To verify the code is correct:
1600001 mHZ : reg 12
1600000 mHZ : reg 12
1599999 mHZ : reg 11
800001 mHZ : reg 11
800000 mHZ : reg 11
799999 mHZ : reg 10
400001 mHZ : reg 10
400000 mHZ : reg 10
399999 mHZ : reg 9
200001 mHZ : reg 9
200000 mHZ : reg 9
199999 mHZ : reg 8
100001 mHZ : reg 8
100000 mHZ : reg 8
99999 mHZ : reg 7
50001 mHZ : reg 7
50000 mHZ : reg 7
49999 mHZ : reg 6
25001 mHZ : reg 6
25000 mHZ : reg 6
24999 mHZ : reg 5
12501 mHZ : reg 5
12500 mHZ : reg 5
12499 mHZ : reg 4
6251 mHZ : reg 4
6250 mHZ : reg 4
6249 mHZ : reg 3
3126 mHZ : reg 3
3125 mHZ : reg 3
3124 mHZ : reg 2
1563 mHZ : reg 2
1562 mHZ : reg 2
1561 mHZ : reg 1

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Change-Id: Iefd0e0c732b52fef02f5b048c083ea67a2da247c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2093289
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
(cherry picked from commit c3dcd2826896e2f2f9b585dcd42ea98d38ae17cc)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2262107
Tested-by: Inno.Park <ih.yoo.park@samsung.corp-partner.google.com>
Reviewed-by: Inno.Park <ih.yoo.park@samsung.corp-partner.google.com>
Reviewed-by: Bob Moragues <moragues@chromium.org>
Commit-Queue: Bob Moragues <moragues@chromium.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/driver/accelgyro_bmi160.h b/driver/accelgyro_bmi160.h
index 626da83217..78f167b305 100644
--- a/driver/accelgyro_bmi160.h
+++ b/driver/accelgyro_bmi160.h
@@ -178,7 +178,7 @@ enum fifo_header {
 	((_regval) < BMI160_ODR_100HZ ? 100000 / (1 << (8 - (_regval))) : \
 					100000 * (1 << ((_regval) - 8)))
 #define BMI160_ODR_TO_REG(_odr) \
-	((_odr) < 100000 ? (__builtin_clz(100000 / (_odr)) - 24) : \
+	((_odr) < 100000 ? (__builtin_clz(100000 / ((_odr) + 1)) - 24) : \
 			   (39 - __builtin_clz((_odr) / 100000)))
 
 #define BMI160_CONF_REG(_sensor)   (0x40 + 2 * (_sensor))