From: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
As reported by Jean-Francois Dagenais, the wheel algorithm caused a
divide by zero exception due to missing variable pre-initialization.
In fact it turned out that the whole algorithm had several problems.
It is therefore replaced with something that is known working.
Signed-off-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
---
drivers/input/misc/ad714x.c | 109 ++++++++-----------------------------------
1 files changed, 19 insertions(+), 90 deletions(-)
diff --git a/drivers/input/misc/ad714x.c b/drivers/input/misc/ad714x.c
index 3e97879..bcc6c9b 100644
--- a/drivers/input/misc/ad714x.c
+++ b/drivers/input/misc/ad714x.c
@@ -79,13 +79,7 @@ struct ad714x_slider_drv {
struct ad714x_wheel_drv {
int abs_pos;
int flt_pos;
- int pre_mean_value;
int pre_highest_stage;
- int pre_mean_value_no_offset;
- int mean_value;
- int mean_value_no_offset;
- int pos_offset;
- int pos_ratio;
int highest_stage;
enum ad714x_device_state state;
struct input_dev *input;
@@ -408,7 +402,6 @@ static void ad714x_slider_state_machine(struct ad714x_chip *ad714x, int idx)
ad714x_slider_cal_highest_stage(ad714x, idx);
ad714x_slider_cal_abs_pos(ad714x, idx);
ad714x_slider_cal_flt_pos(ad714x, idx);
-
input_report_abs(sw->input, ABS_X, sw->flt_pos);
input_report_key(sw->input, BTN_TOUCH, 1);
} else {
@@ -474,104 +467,41 @@ static void ad714x_wheel_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
/*
* When the scroll wheel is activated, we compute the absolute position based
* on the sensor values. To calculate the position, we first determine the
- * sensor that has the greatest response among the 8 sensors that constitutes
- * the scrollwheel. Then we determined the 2 sensors on either sides of the
+ * sensor that has the greatest response among the sensors that constitutes
+ * the scrollwheel. Then we determined the sensors on either sides of the
* sensor with the highest response and we apply weights to these sensors. The
- * result of this computation gives us the mean value which defined by the
- * following formula:
- * For i= second_before_highest_stage to i= second_after_highest_stage
- * v += Sensor response(i)*WEIGHT*(i+3)
- * w += Sensor response(i)
- * Mean_Value=v/w
- * pos_on_scrollwheel = (Mean_Value - position_offset) / position_ratio
+ * result of this computation gives us the mean value.
*/
-#define WEIGHT_FACTOR 30
-/* This constant prevents the "PositionOffset" from reaching a big value */
-#define OFFSET_POSITION_CLAMP 120
static void ad714x_wheel_cal_abs_pos(struct ad714x_chip *ad714x, int idx)
{
struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
int stage_num = hw->end_stage - hw->start_stage + 1;
- int second_before, first_before, highest, first_after, second_after;
+ int first_before, highest, first_after;
int a_param, b_param;
- /* Calculate Mean value */
-
- second_before = (sw->highest_stage + stage_num - 2) % stage_num;
first_before = (sw->highest_stage + stage_num - 1) % stage_num;
highest = sw->highest_stage;
first_after = (sw->highest_stage + stage_num + 1) % stage_num;
- second_after = (sw->highest_stage + stage_num + 2) % stage_num;
-
- if (((sw->highest_stage - hw->start_stage) > 1) &&
- ((hw->end_stage - sw->highest_stage) > 1)) {
- a_param = ad714x->sensor_val[second_before] *
- (second_before - hw->start_stage + 3) +
- ad714x->sensor_val[first_before] *
- (second_before - hw->start_stage + 3) +
- ad714x->sensor_val[highest] *
- (second_before - hw->start_stage + 3) +
- ad714x->sensor_val[first_after] *
- (first_after - hw->start_stage + 3) +
- ad714x->sensor_val[second_after] *
- (second_after - hw->start_stage + 3);
- } else {
- a_param = ad714x->sensor_val[second_before] *
- (second_before - hw->start_stage + 1) +
- ad714x->sensor_val[first_before] *
- (second_before - hw->start_stage + 2) +
- ad714x->sensor_val[highest] *
- (second_before - hw->start_stage + 3) +
- ad714x->sensor_val[first_after] *
- (first_after - hw->start_stage + 4) +
- ad714x->sensor_val[second_after] *
- (second_after - hw->start_stage + 5);
- }
- a_param *= WEIGHT_FACTOR;
- b_param = ad714x->sensor_val[second_before] +
+ a_param = ad714x->sensor_val[highest] *
+ (highest - hw->start_stage) +
+ ad714x->sensor_val[first_before] *
+ (highest - hw->start_stage - 1) +
+ ad714x->sensor_val[first_after] *
+ (highest - hw->start_stage + 1);
+ b_param = ad714x->sensor_val[highest] +
ad714x->sensor_val[first_before] +
- ad714x->sensor_val[highest] +
- ad714x->sensor_val[first_after] +
- ad714x->sensor_val[second_after];
-
- sw->pre_mean_value = sw->mean_value;
- sw->mean_value = a_param / b_param;
-
- /* Calculate the offset */
-
- if ((sw->pre_highest_stage == hw->end_stage) &&
- (sw->highest_stage == hw->start_stage))
- sw->pos_offset = sw->mean_value;
- else if ((sw->pre_highest_stage == hw->start_stage) &&
- (sw->highest_stage == hw->end_stage))
- sw->pos_offset = sw->pre_mean_value;
-
- if (sw->pos_offset > OFFSET_POSITION_CLAMP)
- sw->pos_offset = OFFSET_POSITION_CLAMP;
-
- /* Calculate the mean value without the offset */
-
- sw->pre_mean_value_no_offset = sw->mean_value_no_offset;
- sw->mean_value_no_offset = sw->mean_value - sw->pos_offset;
- if (sw->mean_value_no_offset < 0)
- sw->mean_value_no_offset = 0;
-
- /* Calculate ratio to scale down to NUMBER_OF_WANTED_POSITIONS */
-
- if ((sw->pre_highest_stage == hw->end_stage) &&
- (sw->highest_stage == hw->start_stage))
- sw->pos_ratio = (sw->pre_mean_value_no_offset * 100) /
- hw->max_coord;
- else if ((sw->pre_highest_stage == hw->start_stage) &&
- (sw->highest_stage == hw->end_stage))
- sw->pos_ratio = (sw->mean_value_no_offset * 100) /
- hw->max_coord;
- sw->abs_pos = (sw->mean_value_no_offset * 100) / sw->pos_ratio;
+ ad714x->sensor_val[first_after];
+
+ sw->abs_pos = ((hw->max_coord / (hw->end_stage - hw->start_stage)) *
+ a_param) / b_param;
+
if (sw->abs_pos > hw->max_coord)
sw->abs_pos = hw->max_coord;
+ else if (sw->abs_pos < 0)
+ sw->abs_pos = 0;
}
static void ad714x_wheel_cal_flt_pos(struct ad714x_chip *ad714x, int idx)
@@ -645,9 +575,8 @@ static void ad714x_wheel_state_machine(struct ad714x_chip *ad714x, int idx)
ad714x_wheel_cal_highest_stage(ad714x, idx);
ad714x_wheel_cal_abs_pos(ad714x, idx);
ad714x_wheel_cal_flt_pos(ad714x, idx);
-
input_report_abs(sw->input, ABS_WHEEL,
- sw->abs_pos);
+ sw->flt_pos);
input_report_key(sw->input, BTN_TOUCH, 1);
} else {
/* When the user lifts off the sensor, configure
--
1.6.0.2
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