Use smoothed version of sensor array data to calculate movement and add weight to prior values when calculating average. This gives more granular and more predictable movement.
Signed-off-by: Clinton Sprain <[email protected]> --- drivers/input/mouse/appletouch.c | 60 ++++++++++++++++++++++++++------------ 1 file changed, 42 insertions(+), 18 deletions(-) diff --git a/drivers/input/mouse/appletouch.c b/drivers/input/mouse/appletouch.c index d48181b..edbdd95 100644 --- a/drivers/input/mouse/appletouch.c +++ b/drivers/input/mouse/appletouch.c @@ -338,21 +338,51 @@ static void atp_reinit(struct work_struct *work) static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact, int *z, int *fingers) { - int i; + int i, k; + int smooth[nb_sensors + 2]; + int smooth_tmp[nb_sensors + 2]; + /* values to calculate mean */ int pcum = 0, psum = 0; int is_increasing = 0; *fingers = 0; + /* + * Use a smoothed version of sensor data for movement calculations, to + * combat noise without needing to toss out values based on a threshold. + * This improves tracking. Finger count is calculated separately based + * on raw data. + */ + + for (i = 0; i < nb_sensors; i++) { /* Scale up to minimize */ + smooth[i] = xy_sensors[i] << 12; /* rounding/truncation. */ + } + + /* Mitigate some of the data loss from smoothing on the edge sensors. */ + smooth[-1] = smooth[0] >> 2; + smooth[nb_sensors] = smooth[nb_sensors - 1] >> 2; + + for (k = 0; k < 4; k++) { + for (i = 0; i < nb_sensors; i++) { /* Blend with neighbors. */ + smooth_tmp[i] = (smooth[i - 1] + smooth[i] * 2 + smooth[i + 1]) >> 2; + } + + for (i = 0; i < nb_sensors; i++) { + smooth[i] = smooth_tmp[i]; + if (k == 3) /* Last go-round, so scale back down. */ + smooth[i] = smooth[i] >> 12; + } + + smooth[-1] = smooth[0] >> 2; + smooth[nb_sensors] = smooth[nb_sensors - 1] >> 2; + } + for (i = 0; i < nb_sensors; i++) { if (xy_sensors[i] < threshold) { if (is_increasing) is_increasing = 0; - continue; - } - /* * Makes the finger detection more versatile. For example, * two fingers with no gap will be detected. Also, my @@ -367,7 +397,8 @@ static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact, * * - Jason Parekh <[email protected]> */ - if (i < 1 || + + } else if (i < 1 || (!is_increasing && xy_sensors[i - 1] < xy_sensors[i])) { (*fingers)++; is_increasing = 1; @@ -375,15 +406,8 @@ static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact, is_increasing = 0; } - /* - * Subtracts threshold so a high sensor that just passes the - * threshold won't skew the calculated absolute coordinate. - * Fixes an issue where slowly moving the mouse would - * occasionally jump a number of pixels (slowly moving the - * finger makes this issue most apparent.) - */ - pcum += (xy_sensors[i] - threshold) * i; - psum += (xy_sensors[i] - threshold); + pcum += (smooth[i]) * i; + psum += (smooth[i]); } if (psum > 0) { @@ -565,8 +589,8 @@ static void atp_complete_geyser_1_2(struct urb *urb) if (x && y) { if (dev->x_old != -1) { - x = (dev->x_old * 3 + x) >> 2; - y = (dev->y_old * 3 + y) >> 2; + x = (dev->x_old * 7 + x) >> 3; + y = (dev->y_old * 7 + y) >> 3; dev->x_old = x; dev->y_old = y; @@ -677,8 +701,8 @@ static void atp_complete_geyser_3_4(struct urb *urb) if (x && y) { if (dev->x_old != -1) { - x = (dev->x_old * 3 + x) >> 2; - y = (dev->y_old * 3 + y) >> 2; + x = (dev->x_old * 7 + x) >> 3; + y = (dev->y_old * 7 + y) >> 3; dev->x_old = x; dev->y_old = y; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
