1 files changed, 108 insertions, 35 deletions

diff --git a/drivers/input/mouse/appletouch.c b/drivers/input/mouse/appletouch.c
index 800ca7dfafc..ef234c9b2f2 100644
--- a/drivers/input/mouse/appletouch.c
+++ b/drivers/input/mouse/appletouch.c
@@ -48,6 +48,7 @@ struct atp_info {
 	int yfact;				/* Y multiplication factor */
 	int datalen;				/* size of USB transfers */
 	void (*callback)(struct urb *);		/* callback function */
+	int fuzz;				/* fuzz touchpad generates */
 };
 
 static void atp_complete_geyser_1_2(struct urb *urb);
@@ -61,6 +62,7 @@ static const struct atp_info fountain_info = {
 	.yfact		= 43,
 	.datalen	= 81,
 	.callback	= atp_complete_geyser_1_2,
+	.fuzz		= 16,
 };
 
 static const struct atp_info geyser1_info = {
@@ -71,6 +73,7 @@ static const struct atp_info geyser1_info = {
 	.yfact		= 43,
 	.datalen	= 81,
 	.callback	= atp_complete_geyser_1_2,
+	.fuzz		= 16,
 };
 
 static const struct atp_info geyser2_info = {
@@ -81,6 +84,7 @@ static const struct atp_info geyser2_info = {
 	.yfact		= 43,
 	.datalen	= 64,
 	.callback	= atp_complete_geyser_1_2,
+	.fuzz		= 0,
 };
 
 static const struct atp_info geyser3_info = {
@@ -90,6 +94,7 @@ static const struct atp_info geyser3_info = {
 	.yfact		= 64,
 	.datalen	= 64,
 	.callback	= atp_complete_geyser_3_4,
+	.fuzz		= 0,
 };
 
 static const struct atp_info geyser4_info = {
@@ -99,6 +104,7 @@ static const struct atp_info geyser4_info = {
 	.yfact		= 64,
 	.datalen	= 64,
 	.callback	= atp_complete_geyser_3_4,
+	.fuzz		= 0,
 };
 
 #define ATP_DEVICE(prod, info)					\
@@ -155,8 +161,11 @@ MODULE_DEVICE_TABLE(usb, atp_table);
 #define ATP_XSENSORS	26
 #define ATP_YSENSORS	16
 
-/* amount of fuzz this touchpad generates */
-#define ATP_FUZZ	16
+/*
+ * The largest possible bank of sensors with additional buffer of 4 extra values
+ * on either side, for an array of smoothed sensor values.
+ */
+#define ATP_SMOOTHSIZE	34
 
 /* maximum pressure this driver will report */
 #define ATP_PRESSURE	300
@@ -165,7 +174,13 @@ MODULE_DEVICE_TABLE(usb, atp_table);
  * Threshold for the touchpad sensors. Any change less than ATP_THRESHOLD is
  * ignored.
  */
-#define ATP_THRESHOLD	 5
+#define ATP_THRESHOLD	5
+
+/*
+ * How far we'll bitshift our sensor values before averaging them. Mitigates
+ * rounding errors.
+ */
+#define ATP_SCALE	12
 
 /* Geyser initialization constants */
 #define ATP_GEYSER_MODE_READ_REQUEST_ID		1
@@ -203,11 +218,14 @@ struct atp {
 	bool			valid;		/* are the samples valid? */
 	bool			size_detect_done;
 	bool			overflow_warned;
+	int			fingers_old;	/* last reported finger count */
 	int			x_old;		/* last reported x/y, */
 	int			y_old;		/* used for smoothing */
 	signed char		xy_cur[ATP_XSENSORS + ATP_YSENSORS];
 	signed char		xy_old[ATP_XSENSORS + ATP_YSENSORS];
 	int			xy_acc[ATP_XSENSORS + ATP_YSENSORS];
+	int			smooth[ATP_SMOOTHSIZE];
+	int			smooth_tmp[ATP_SMOOTHSIZE];
 	int			idlecount;	/* number of empty packets */
 	struct work_struct	work;
 };
@@ -326,10 +344,17 @@ static void atp_reinit(struct work_struct *work)
 			retval);
 }
 
-static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact,
-			     int *z, int *fingers)
+static int atp_calculate_abs(struct atp *dev, int offset, int nb_sensors,
+			     int fact, int *z, int *fingers)
 {
-	int i;
+	int i, pass;
+
+	/*
+	 * Use offset to point xy_sensors at the first value in dev->xy_acc
+	 * for whichever dimension we're looking at this particular go-round.
+	 */
+	int *xy_sensors = dev->xy_acc + offset;
+
 	/* values to calculate mean */
 	int pcum = 0, psum = 0;
 	int is_increasing = 0;
@@ -341,9 +366,6 @@ static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact,
 			if (is_increasing)
 				is_increasing = 0;
 
-			continue;
-		}
-
 		/*
 		 * Makes the finger detection more versatile.  For example,
 		 * two fingers with no gap will be detected.  Also, my
@@ -358,27 +380,63 @@ static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact,
 		 *
 		 * - Jason Parekh <jasonparekh@gmail.com>
 		 */
-		if (i < 1 ||
+
+		} else if (i < 1 ||
 		    (!is_increasing && xy_sensors[i - 1] < xy_sensors[i])) {
 			(*fingers)++;
 			is_increasing = 1;
 		} else if (i > 0 && (xy_sensors[i - 1] - xy_sensors[i] > threshold)) {
 			is_increasing = 0;
 		}
+	}
+
+	if (*fingers < 1)     /* No need to continue if no fingers are found. */
+		return 0;
 
+	/*
+	 * Use a smoothed version of sensor data for movement calculations, to
+	 * combat noise without needing to rely so heavily on a threshold.
+	 * This improves tracking.
+	 *
+	 * The smoothed array is bigger than the original so that the smoothing
+	 * doesn't result in edge values being truncated.
+	 */
+
+	memset(dev->smooth, 0, 4 * sizeof(dev->smooth[0]));
+	/* Pull base values, scaled up to help avoid truncation errors. */
+	for (i = 0; i < nb_sensors; i++)
+		dev->smooth[i + 4] = xy_sensors[i] << ATP_SCALE;
+	memset(&dev->smooth[nb_sensors + 4], 0, 4 * sizeof(dev->smooth[0]));
+
+	for (pass = 0; pass < 4; pass++) {
+		/* Handle edge. */
+		dev->smooth_tmp[0] = (dev->smooth[0] + dev->smooth[1]) / 2;
+
+		/* Average values with neighbors. */
+		for (i = 1; i < nb_sensors + 7; i++)
+			dev->smooth_tmp[i] = (dev->smooth[i - 1] +
+					      dev->smooth[i] * 2 +
+					      dev->smooth[i + 1]) / 4;
+
+		/* Handle other edge. */
+		dev->smooth_tmp[i] = (dev->smooth[i - 1] + dev->smooth[i]) / 2;
+
+		memcpy(dev->smooth, dev->smooth_tmp, sizeof(dev->smooth));
+	}
+
+	for (i = 0; i < nb_sensors + 8; i++) {
 		/*
-		 * Subtracts threshold so a high sensor that just passes the
-		 * threshold won't skew the calculated absolute coordinate.
-		 * Fixes an issue where slowly moving the mouse would
-		 * occasionally jump a number of pixels (slowly moving the
-		 * finger makes this issue most apparent.)
+		 * Skip values if they're small enough to be truncated to 0
+		 * by scale. Mostly noise.
 		 */
-		pcum += (xy_sensors[i] - threshold) * i;
-		psum += (xy_sensors[i] - threshold);
+		if ((dev->smooth[i] >> ATP_SCALE) > 0) {
+			pcum += dev->smooth[i] * i;
+			psum += dev->smooth[i];
+		}
 	}
 
 	if (psum > 0) {
-		*z = psum;
+		*z = psum >> ATP_SCALE;        /* Scale down pressure output. */
 		return pcum * fact / psum;
 	}
 
@@ -455,7 +513,7 @@ static void atp_detect_size(struct atp *dev)
 			input_set_abs_params(dev->input, ABS_X, 0,
 					     (dev->info->xsensors_17 - 1) *
 							dev->info->xfact - 1,
-					     ATP_FUZZ, 0);
+					     dev->info->fuzz, 0);
 			break;
 		}
 	}
@@ -471,7 +529,7 @@ static void atp_complete_geyser_1_2(struct urb *urb)
 {
 	int x, y, x_z, y_z, x_f, y_f;
 	int retval, i, j;
-	int key;
+	int key, fingers;
 	struct atp *dev = urb->context;
 	int status = atp_status_check(urb);
 
@@ -548,16 +606,18 @@ static void atp_complete_geyser_1_2(struct urb *urb)
 
 	dbg_dump("accumulator", dev->xy_acc);
 
-	x = atp_calculate_abs(dev->xy_acc, ATP_XSENSORS,
+	x = atp_calculate_abs(dev, 0, ATP_XSENSORS,
 			      dev->info->xfact, &x_z, &x_f);
-	y = atp_calculate_abs(dev->xy_acc + ATP_XSENSORS, ATP_YSENSORS,
+	y = atp_calculate_abs(dev, ATP_XSENSORS, ATP_YSENSORS,
 			      dev->info->yfact, &y_z, &y_f);
 	key = dev->data[dev->info->datalen - 1] & ATP_STATUS_BUTTON;
 
-	if (x && y) {
+	fingers = max(x_f, y_f);
+
+	if (x && y && fingers == dev->fingers_old) {
 		if (dev->x_old != -1) {
-			x = (dev->x_old * 3 + x) >> 2;
-			y = (dev->y_old * 3 + y) >> 2;
+			x = (dev->x_old * 7 + x) >> 3;
+			y = (dev->y_old * 7 + y) >> 3;
 			dev->x_old = x;
 			dev->y_old = y;
 
@@ -571,7 +631,7 @@ static void atp_complete_geyser_1_2(struct urb *urb)
 			input_report_abs(dev->input, ABS_Y, y);
 			input_report_abs(dev->input, ABS_PRESSURE,
 					 min(ATP_PRESSURE, x_z + y_z));
-			atp_report_fingers(dev->input, max(x_f, y_f));
+			atp_report_fingers(dev->input, fingers);
 		}
 		dev->x_old = x;
 		dev->y_old = y;
@@ -579,6 +639,7 @@ static void atp_complete_geyser_1_2(struct urb *urb)
 	} else if (!x && !y) {
 
 		dev->x_old = dev->y_old = -1;
+		dev->fingers_old = 0;
 		input_report_key(dev->input, BTN_TOUCH, 0);
 		input_report_abs(dev->input, ABS_PRESSURE, 0);
 		atp_report_fingers(dev->input, 0);
@@ -587,6 +648,10 @@ static void atp_complete_geyser_1_2(struct urb *urb)
 		memset(dev->xy_acc, 0, sizeof(dev->xy_acc));
 	}
 
+	if (fingers != dev->fingers_old)
+		dev->x_old = dev->y_old = -1;
+	dev->fingers_old = fingers;
+
 	input_report_key(dev->input, BTN_LEFT, key);
 	input_sync(dev->input);
 
@@ -604,7 +669,7 @@ static void atp_complete_geyser_3_4(struct urb *urb)
 {
 	int x, y, x_z, y_z, x_f, y_f;
 	int retval, i, j;
-	int key;
+	int key, fingers;
 	struct atp *dev = urb->context;
 	int status = atp_status_check(urb);
 
@@ -660,16 +725,19 @@ static void atp_complete_geyser_3_4(struct urb *urb)
 
 	dbg_dump("accumulator", dev->xy_acc);
 
-	x = atp_calculate_abs(dev->xy_acc, ATP_XSENSORS,
+	x = atp_calculate_abs(dev, 0, ATP_XSENSORS,
 			      dev->info->xfact, &x_z, &x_f);
-	y = atp_calculate_abs(dev->xy_acc + ATP_XSENSORS, ATP_YSENSORS,
+	y = atp_calculate_abs(dev, ATP_XSENSORS, ATP_YSENSORS,
 			      dev->info->yfact, &y_z, &y_f);
+
 	key = dev->data[dev->info->datalen - 1] & ATP_STATUS_BUTTON;
 
-	if (x && y) {
+	fingers = max(x_f, y_f);
+
+	if (x && y && fingers == dev->fingers_old) {
 		if (dev->x_old != -1) {
-			x = (dev->x_old * 3 + x) >> 2;
-			y = (dev->y_old * 3 + y) >> 2;
+			x = (dev->x_old * 7 + x) >> 3;
+			y = (dev->y_old * 7 + y) >> 3;
 			dev->x_old = x;
 			dev->y_old = y;
 
@@ -683,7 +751,7 @@ static void atp_complete_geyser_3_4(struct urb *urb)
 			input_report_abs(dev->input, ABS_Y, y);
 			input_report_abs(dev->input, ABS_PRESSURE,
 					 min(ATP_PRESSURE, x_z + y_z));
-			atp_report_fingers(dev->input, max(x_f, y_f));
+			atp_report_fingers(dev->input, fingers);
 		}
 		dev->x_old = x;
 		dev->y_old = y;
@@ -691,6 +759,7 @@ static void atp_complete_geyser_3_4(struct urb *urb)
 	} else if (!x && !y) {
 
 		dev->x_old = dev->y_old = -1;
+		dev->fingers_old = 0;
 		input_report_key(dev->input, BTN_TOUCH, 0);
 		input_report_abs(dev->input, ABS_PRESSURE, 0);
 		atp_report_fingers(dev->input, 0);
@@ -699,6 +768,10 @@ static void atp_complete_geyser_3_4(struct urb *urb)
 		memset(dev->xy_acc, 0, sizeof(dev->xy_acc));
 	}
 
+	if (fingers != dev->fingers_old)
+		dev->x_old = dev->y_old = -1;
+	dev->fingers_old = fingers;
+
 	input_report_key(dev->input, BTN_LEFT, key);
 	input_sync(dev->input);
 
@@ -843,10 +916,10 @@ static int atp_probe(struct usb_interface *iface,
 
 	input_set_abs_params(input_dev, ABS_X, 0,
 			     (dev->info->xsensors - 1) * dev->info->xfact - 1,
-			     ATP_FUZZ, 0);
+			     dev->info->fuzz, 0);
 	input_set_abs_params(input_dev, ABS_Y, 0,
 			     (dev->info->ysensors - 1) * dev->info->yfact - 1,
-			     ATP_FUZZ, 0);
+			     dev->info->fuzz, 0);
 	input_set_abs_params(input_dev, ABS_PRESSURE, 0, ATP_PRESSURE, 0, 0);
 
 	set_bit(EV_KEY, input_dev->evbit);