1 files changed, 52 insertions, 40 deletions

diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
index 7c0f6b21559d..191a1b87895f 100644
--- a/drivers/input/touchscreen/ti_am335x_tsc.c
+++ b/drivers/input/touchscreen/ti_am335x_tsc.c
@@ -26,6 +26,7 @@
 #include <linux/delay.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/sort.h>
 
 #include <linux/mfd/ti_am335x_tscadc.h>
 
@@ -204,56 +205,61 @@ static void titsc_step_config(struct titsc *ts_dev)
 	am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask);
 }
 
+static int titsc_cmp_coord(const void *a, const void *b)
+{
+	return *(int *)a - *(int *)b;
+}
+
 static void titsc_read_coordinates(struct titsc *ts_dev,
 		u32 *x, u32 *y, u32 *z1, u32 *z2)
 {
-	unsigned int fifocount = titsc_readl(ts_dev, REG_FIFO0CNT);
-	unsigned int prev_val_x = ~0, prev_val_y = ~0;
-	unsigned int prev_diff_x = ~0, prev_diff_y = ~0;
-	unsigned int read, diff;
-	unsigned int i, channel;
+	unsigned int yvals[7], xvals[7];
+	unsigned int i, xsum = 0, ysum = 0;
 	unsigned int creads = ts_dev->coordinate_readouts;
-	unsigned int first_step = TOTAL_STEPS - (creads * 2 + 2);
 
-	*z1 = *z2 = 0;
-	if (fifocount % (creads * 2 + 2))
-		fifocount -= fifocount % (creads * 2 + 2);
-	/*
-	 * Delta filter is used to remove large variations in sampled
-	 * values from ADC. The filter tries to predict where the next
-	 * coordinate could be. This is done by taking a previous
-	 * coordinate and subtracting it form current one. Further the
-	 * algorithm compares the difference with that of a present value,
-	 * if true the value is reported to the sub system.
-	 */
-	for (i = 0; i < fifocount; i++) {
-		read = titsc_readl(ts_dev, REG_FIFO0);
-
-		channel = (read & 0xf0000) >> 16;
-		read &= 0xfff;
-		if (channel > first_step + creads + 2) {
-			diff = abs(read - prev_val_x);
-			if (diff < prev_diff_x) {
-				prev_diff_x = diff;
-				*x = read;
-			}
-			prev_val_x = read;
+	for (i = 0; i < creads; i++) {
+		yvals[i] = titsc_readl(ts_dev, REG_FIFO0);
+		yvals[i] &= 0xfff;
+	}
 
-		} else if (channel == first_step + creads + 1) {
-			*z1 = read;
+	*z1 = titsc_readl(ts_dev, REG_FIFO0);
+	*z1 &= 0xfff;
+	*z2 = titsc_readl(ts_dev, REG_FIFO0);
+	*z2 &= 0xfff;
 
-		} else if (channel == first_step + creads + 2) {
-			*z2 = read;
+	for (i = 0; i < creads; i++) {
+		xvals[i] = titsc_readl(ts_dev, REG_FIFO0);
+		xvals[i] &= 0xfff;
+	}
 
-		} else if (channel > first_step) {
-			diff = abs(read - prev_val_y);
-			if (diff < prev_diff_y) {
-				prev_diff_y = diff;
-				*y = read;
-			}
-			prev_val_y = read;
+	/*
+	 * If co-ordinates readouts is less than 4 then
+	 * report the average. In case of 4 or more
+	 * readouts, sort the co-ordinate samples, drop
+	 * min and max values and report the average of
+	 * remaining values.
+	 */
+	if (creads <=  3) {
+		for (i = 0; i < creads; i++) {
+			ysum += yvals[i];
+			xsum += xvals[i];
 		}
+		ysum /= creads;
+		xsum /= creads;
+	} else {
+		sort(yvals, creads, sizeof(unsigned int),
+		     titsc_cmp_coord, NULL);
+		sort(xvals, creads, sizeof(unsigned int),
+		     titsc_cmp_coord, NULL);
+		for (i = 1; i < creads - 1; i++) {
+			ysum += yvals[i];
+			xsum += xvals[i];
+		}
+		ysum /= creads - 2;
+		xsum /= creads - 2;
 	}
+	*y = ysum;
+	*x = xsum;
 }
 
 static irqreturn_t titsc_irq(int irq, void *dev)
@@ -369,6 +375,12 @@ static int titsc_parse_dt(struct platform_device *pdev,
 	if (err < 0)
 		return err;
 
+	if (ts_dev->coordinate_readouts <= 0) {
+		dev_warn(&pdev->dev,
+			 "invalid co-ordinate readouts, resetting it to 5\n");
+		ts_dev->coordinate_readouts = 5;
+	}
+
 	err = of_property_read_u32(node, "ti,charge-delay",
 				   &ts_dev->charge_delay);
 	/*