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| author | Cyan Ogilvie <cyan.ogilvie@gmail.com> | 2016-03-16 19:59:41 +0300 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2016-03-18 19:31:38 +0300 |
| commit | d30596737e8e7b2f1235d7ba20592b8309e3af04 (patch) | |
| tree | 4074e2ad70bff2b085a6e7025e8f202b16c33aeb /drivers/hid/hid-wiimote-modules.c | |
| parent | d66435cc7da95964cb386674bd82ec12ca66320a (diff) | |
| download | linux-d30596737e8e7b2f1235d7ba20592b8309e3af04.tar.xz | |
HID: wiimote: Fix wiimote mp scale linearization
The wiimote motion plus gyros use two scales to report fast and slow
rotation - below 440 deg/s uses 8192/440 units / deg/s, and above uses
8192/2000 units / deg/s.
Previously this driver attempted to linearize the two by scaling the fast
rate by 18 and the slow by 9, but this results in a scale of
8192*9/440 = ~167.564 for slow and 8192*18/2000 = 73.728 for fast.
Correct the fast motion scale factor so that both report ~167.564
units / deg/s
Signed-off-by: Cyan Ogilvie <cyan.ogilvie@gmail.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'drivers/hid/hid-wiimote-modules.c')
| -rw-r--r-- | drivers/hid/hid-wiimote-modules.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/drivers/hid/hid-wiimote-modules.c b/drivers/hid/hid-wiimote-modules.c index 4390eee2ce84..c830ed39348f 100644 --- a/drivers/hid/hid-wiimote-modules.c +++ b/drivers/hid/hid-wiimote-modules.c @@ -2049,9 +2049,11 @@ static void wiimod_mp_in_mp(struct wiimote_data *wdata, const __u8 *ext) * -----+------------------------------+-----+-----+ * The single bits Yaw, Roll, Pitch in the lower right corner specify * whether the wiimote is rotating fast (0) or slow (1). Speed for slow - * roation is 440 deg/s and for fast rotation 2000 deg/s. To get a - * linear scale we multiply by 2000/440 = ~4.5454 which is 18 for fast - * and 9 for slow. + * roation is 8192/440 units / deg/s and for fast rotation 8192/2000 + * units / deg/s. To get a linear scale for fast rotation we multiply + * by 2000/440 = ~4.5454 and scale both fast and slow by 9 to match the + * previous scale reported by this driver. + * This leaves a linear scale with 8192*9/440 (~167.564) units / deg/s. * If the wiimote is not rotating the sensor reports 2^13 = 8192. * Ext specifies whether an extension is connected to the motionp. * which is parsed by wiimote-core. @@ -2070,15 +2072,15 @@ static void wiimod_mp_in_mp(struct wiimote_data *wdata, const __u8 *ext) z -= 8192; if (!(ext[3] & 0x02)) - x *= 18; + x = (x * 2000 * 9) / 440; else x *= 9; if (!(ext[4] & 0x02)) - y *= 18; + y = (y * 2000 * 9) / 440; else y *= 9; if (!(ext[3] & 0x01)) - z *= 18; + z = (z * 2000 * 9) / 440; else z *= 9; |