[PATCH RESEND 3/7] input: ti_am335x_tsc: Add variance filter
From: Patil, Rachna <hidden>
Date: 2012-11-07 07:08:51
Also in:
linux-devicetree, linux-iio, lkml
Subsystem:
input (keyboard, mouse, joystick, touchscreen) drivers, the rest · Maintainers:
Dmitry Torokhov, Linus Torvalds
Only fine tuning variance parameter present in tslib utility does not help in removing all the ADC noise. This logic of filtering is necessary to get this touchscreen to work finely. Signed-off-by: Patil, Rachna <redacted> --- drivers/input/touchscreen/ti_am335x_tsc.c | 15 ++++++++++++++- 1 files changed, 14 insertions(+), 1 deletions(-)
diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
index 6a817a8..7a26810 100644
--- a/drivers/input/touchscreen/ti_am335x_tsc.c
+++ b/drivers/input/touchscreen/ti_am335x_tsc.c@@ -32,6 +32,8 @@ #define ADCFSM_STEPID 0x10 #define SEQ_SETTLE 275 #define MAX_12BIT ((1 << 12) - 1) +#define TSCADC_DELTA_X 15 +#define TSCADC_DELTA_Y 15 /* * Refer to function regbit_map() to
@@ -51,6 +53,8 @@ struct titsc { unsigned int wires; unsigned int x_plate_resistance; unsigned int enable_bits; + unsigned int bckup_x; + unsigned int bckup_y; bool pen_down; int steps_to_configure; int config_inp[20];
@@ -309,12 +313,18 @@ static irqreturn_t titsc_irq(int irq, void *dev) unsigned int z1, z2, z; unsigned int fsm; unsigned int fifo1count, fifo0count; + unsigned int diffx = 0, diffy = 0; int i; status = titsc_readl(ts_dev, REG_IRQSTATUS); if (status & IRQENB_FIFO0THRES) { titsc_read_coordinates(ts_dev, &x, &y); + diffx = abs(x - (ts_dev->bckup_x)); + diffy = abs(y - (ts_dev->bckup_y)); + ts_dev->bckup_x = x; + ts_dev->bckup_y = y; + z1 = titsc_readl(ts_dev, REG_FIFO0) & 0xfff; z2 = titsc_readl(ts_dev, REG_FIFO1) & 0xfff;
@@ -338,7 +348,8 @@ static irqreturn_t titsc_irq(int irq, void *dev) z /= z1; z = (z + 2047) >> 12; - if (z <= MAX_12BIT) { + if ((diffx < TSCADC_DELTA_X) && + (diffy < TSCADC_DELTA_Y) && (z <= MAX_12BIT)) { input_report_abs(input_dev, ABS_X, x); input_report_abs(input_dev, ABS_Y, y); input_report_abs(input_dev, ABS_PRESSURE, z);
@@ -361,6 +372,8 @@ static irqreturn_t titsc_irq(int irq, void *dev) fsm = titsc_readl(ts_dev, REG_ADCFSM); if (fsm == ADCFSM_STEPID) { ts_dev->pen_down = false; + ts_dev->bckup_x = 0; + ts_dev->bckup_y = 0; input_report_key(input_dev, BTN_TOUCH, 0); input_report_abs(input_dev, ABS_PRESSURE, 0); input_sync(input_dev);
--
1.7.0.4