From f1e430e6369f5edac552d99bff15369ef8c6bbd2 Mon Sep 17 00:00:00 2001 From: Michael Hennerich Date: Mon, 16 May 2011 23:17:40 -0700 Subject: [PATCH] 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 Tested-by: Jean-Francois Dagenais Signed-off-by: Dmitry Torokhov --- drivers/input/misc/ad714x.c | 109 ++++++++------------------------------------ 1 file changed, 19 insertions(+), 90 deletions(-) diff --git a/drivers/input/misc/ad714x.c b/drivers/input/misc/ad714x.c index 5f683ec2999e..c3a62c42cd28 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; @@ -404,7 +398,6 @@ 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 { @@ -468,104 +461,41 @@ 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) @@ -639,9 +569,8 @@ 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 -- 2.11.0