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Input: ad714x - fix captouch wheel option algorithm
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@analog.com> Tested-by: Jean-Francois Dagenais <jeff.dagenais@gmail.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
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3532cb0ca2
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1 changed files with 17 additions and 88 deletions
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@ -79,13 +79,7 @@ struct ad714x_slider_drv {
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struct ad714x_wheel_drv {
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int abs_pos;
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int flt_pos;
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int pre_mean_value;
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int pre_highest_stage;
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int pre_mean_value_no_offset;
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int mean_value;
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int mean_value_no_offset;
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int pos_offset;
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int pos_ratio;
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int highest_stage;
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enum ad714x_device_state state;
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struct input_dev *input;
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@ -404,7 +398,6 @@ static void ad714x_slider_state_machine(struct ad714x_chip *ad714x, int idx)
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ad714x_slider_cal_highest_stage(ad714x, idx);
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ad714x_slider_cal_abs_pos(ad714x, idx);
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ad714x_slider_cal_flt_pos(ad714x, idx);
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input_report_abs(sw->input, ABS_X, sw->flt_pos);
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input_report_key(sw->input, BTN_TOUCH, 1);
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} else {
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@ -468,104 +461,41 @@ static void ad714x_wheel_cal_sensor_val(struct ad714x_chip *ad714x, int idx)
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/*
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* When the scroll wheel is activated, we compute the absolute position based
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* on the sensor values. To calculate the position, we first determine the
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* sensor that has the greatest response among the 8 sensors that constitutes
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* the scrollwheel. Then we determined the 2 sensors on either sides of the
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* sensor that has the greatest response among the sensors that constitutes
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* the scrollwheel. Then we determined the sensors on either sides of the
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* sensor with the highest response and we apply weights to these sensors. The
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* result of this computation gives us the mean value which defined by the
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* following formula:
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* For i= second_before_highest_stage to i= second_after_highest_stage
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* v += Sensor response(i)*WEIGHT*(i+3)
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* w += Sensor response(i)
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* Mean_Value=v/w
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* pos_on_scrollwheel = (Mean_Value - position_offset) / position_ratio
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* result of this computation gives us the mean value.
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*/
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#define WEIGHT_FACTOR 30
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/* This constant prevents the "PositionOffset" from reaching a big value */
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#define OFFSET_POSITION_CLAMP 120
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static void ad714x_wheel_cal_abs_pos(struct ad714x_chip *ad714x, int idx)
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{
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struct ad714x_wheel_plat *hw = &ad714x->hw->wheel[idx];
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struct ad714x_wheel_drv *sw = &ad714x->sw->wheel[idx];
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int stage_num = hw->end_stage - hw->start_stage + 1;
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int second_before, first_before, highest, first_after, second_after;
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int first_before, highest, first_after;
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int a_param, b_param;
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/* Calculate Mean value */
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second_before = (sw->highest_stage + stage_num - 2) % stage_num;
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first_before = (sw->highest_stage + stage_num - 1) % stage_num;
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highest = sw->highest_stage;
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first_after = (sw->highest_stage + stage_num + 1) % stage_num;
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second_after = (sw->highest_stage + stage_num + 2) % stage_num;
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if (((sw->highest_stage - hw->start_stage) > 1) &&
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((hw->end_stage - sw->highest_stage) > 1)) {
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a_param = ad714x->sensor_val[second_before] *
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(second_before - hw->start_stage + 3) +
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ad714x->sensor_val[first_before] *
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(second_before - hw->start_stage + 3) +
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ad714x->sensor_val[highest] *
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(second_before - hw->start_stage + 3) +
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ad714x->sensor_val[first_after] *
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(first_after - hw->start_stage + 3) +
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ad714x->sensor_val[second_after] *
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(second_after - hw->start_stage + 3);
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} else {
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a_param = ad714x->sensor_val[second_before] *
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(second_before - hw->start_stage + 1) +
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ad714x->sensor_val[first_before] *
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(second_before - hw->start_stage + 2) +
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ad714x->sensor_val[highest] *
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(second_before - hw->start_stage + 3) +
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ad714x->sensor_val[first_after] *
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(first_after - hw->start_stage + 4) +
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ad714x->sensor_val[second_after] *
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(second_after - hw->start_stage + 5);
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}
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a_param *= WEIGHT_FACTOR;
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b_param = ad714x->sensor_val[second_before] +
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a_param = ad714x->sensor_val[highest] *
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(highest - hw->start_stage) +
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ad714x->sensor_val[first_before] *
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(highest - hw->start_stage - 1) +
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ad714x->sensor_val[first_after] *
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(highest - hw->start_stage + 1);
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b_param = ad714x->sensor_val[highest] +
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ad714x->sensor_val[first_before] +
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ad714x->sensor_val[highest] +
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ad714x->sensor_val[first_after] +
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ad714x->sensor_val[second_after];
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ad714x->sensor_val[first_after];
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sw->pre_mean_value = sw->mean_value;
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sw->mean_value = a_param / b_param;
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sw->abs_pos = ((hw->max_coord / (hw->end_stage - hw->start_stage)) *
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a_param) / b_param;
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/* Calculate the offset */
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if ((sw->pre_highest_stage == hw->end_stage) &&
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(sw->highest_stage == hw->start_stage))
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sw->pos_offset = sw->mean_value;
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else if ((sw->pre_highest_stage == hw->start_stage) &&
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(sw->highest_stage == hw->end_stage))
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sw->pos_offset = sw->pre_mean_value;
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if (sw->pos_offset > OFFSET_POSITION_CLAMP)
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sw->pos_offset = OFFSET_POSITION_CLAMP;
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/* Calculate the mean value without the offset */
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sw->pre_mean_value_no_offset = sw->mean_value_no_offset;
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sw->mean_value_no_offset = sw->mean_value - sw->pos_offset;
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if (sw->mean_value_no_offset < 0)
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sw->mean_value_no_offset = 0;
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/* Calculate ratio to scale down to NUMBER_OF_WANTED_POSITIONS */
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if ((sw->pre_highest_stage == hw->end_stage) &&
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(sw->highest_stage == hw->start_stage))
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sw->pos_ratio = (sw->pre_mean_value_no_offset * 100) /
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hw->max_coord;
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else if ((sw->pre_highest_stage == hw->start_stage) &&
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(sw->highest_stage == hw->end_stage))
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sw->pos_ratio = (sw->mean_value_no_offset * 100) /
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hw->max_coord;
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sw->abs_pos = (sw->mean_value_no_offset * 100) / sw->pos_ratio;
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if (sw->abs_pos > hw->max_coord)
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sw->abs_pos = hw->max_coord;
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else if (sw->abs_pos < 0)
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sw->abs_pos = 0;
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}
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static void ad714x_wheel_cal_flt_pos(struct ad714x_chip *ad714x, int idx)
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@ -639,9 +569,8 @@ static void ad714x_wheel_state_machine(struct ad714x_chip *ad714x, int idx)
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ad714x_wheel_cal_highest_stage(ad714x, idx);
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ad714x_wheel_cal_abs_pos(ad714x, idx);
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ad714x_wheel_cal_flt_pos(ad714x, idx);
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input_report_abs(sw->input, ABS_WHEEL,
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sw->abs_pos);
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sw->flt_pos);
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input_report_key(sw->input, BTN_TOUCH, 1);
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} else {
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/* When the user lifts off the sensor, configure
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