[PATCH 1/3] input: appletouch: parametrize and set saner defaults for fuzz and threshold

[Clinton Sprain <clintonsprain@gmail.com>]

Dials back the default fuzz and threshold settings for
most devices using this driver, based on values from
user feedback from forums and bug reports. This
increases smoothness and movement granularity. No
changes were made for the older devices that use the
driver, as I did not find any user feedback for them
regarding these settings; however, the two settings can
also now both be specified as module parameters in case
there is a desire to change the values for devices that
do not have new defaults.

There are also a couple of style cleanups per checkpatch.pl.

Signed-off-by: Clinton Sprain <clintonsprain@gmail.com>
---
 drivers/input/mouse/appletouch.c |   66 ++++++++++++++++++++++++--------------
 1 file changed, 42 insertions(+), 24 deletions(-)

diff --git a/drivers/input/mouse/appletouch.c b/drivers/input/mouse/appletouch.c
index e42f1fa..f5a16ee 100644
--- a/drivers/input/mouse/appletouch.c
+++ b/drivers/input/mouse/appletouch.c
@@ -43,12 +43,14 @@
  */
 struct atp_info {
 	int xsensors;				/* number of X sensors */
-	int xsensors_17;			/* 17" models have more sensors */
+	int xsensors_17;			/* 17" model has more sensors */
 	int ysensors;				/* number of Y sensors */
 	int xfact;				/* X multiplication factor */
 	int yfact;				/* Y multiplication factor */
 	int datalen;				/* size of USB transfers */
 	void (*callback)(struct urb *);		/* callback function */
+	int fuzz;				/* fuzz touchpad generates */
+	int threshold;				/* sensitivity threshold */
 };
 
 static void atp_complete_geyser_1_2(struct urb *urb);
@@ -62,6 +64,8 @@ static const struct atp_info fountain_info = {
 	.yfact		= 43,
 	.datalen	= 81,
 	.callback	= atp_complete_geyser_1_2,
+	.fuzz		= 16,
+	.threshold	= 5,
 };
 
 static const struct atp_info geyser1_info = {
@@ -72,6 +76,8 @@ static const struct atp_info geyser1_info = {
 	.yfact		= 43,
 	.datalen	= 81,
 	.callback	= atp_complete_geyser_1_2,
+	.fuzz		= 16,
+	.threshold	= 5,
 };
 
 static const struct atp_info geyser2_info = {
@@ -82,6 +88,8 @@ static const struct atp_info geyser2_info = {
 	.yfact		= 43,
 	.datalen	= 64,
 	.callback	= atp_complete_geyser_1_2,
+	.fuzz		= 0,
+	.threshold	= 3,
 };
 
 static const struct atp_info geyser3_info = {
@@ -91,6 +99,8 @@ static const struct atp_info geyser3_info = {
 	.yfact		= 64,
 	.datalen	= 64,
 	.callback	= atp_complete_geyser_3_4,
+	.fuzz		= 0,
+	.threshold	= 3,
 };
 
 static const struct atp_info geyser4_info = {
@@ -100,6 +110,8 @@ static const struct atp_info geyser4_info = {
 	.yfact		= 64,
 	.datalen	= 64,
 	.callback	= atp_complete_geyser_3_4,
+	.fuzz		= 0,
+	.threshold	= 3,
 };
 
 #define ATP_DEVICE(prod, info)					\
@@ -156,18 +168,9 @@ MODULE_DEVICE_TABLE(usb, atp_table);
 #define ATP_XSENSORS	26
 #define ATP_YSENSORS	16
 
-/* amount of fuzz this touchpad generates */
-#define ATP_FUZZ	16
-
 /* maximum pressure this driver will report */
 #define ATP_PRESSURE	300
 
-/*
- * Threshold for the touchpad sensors. Any change less than ATP_THRESHOLD is
- * ignored.
- */
-#define ATP_THRESHOLD	 5
-
 /* Geyser initialization constants */
 #define ATP_GEYSER_MODE_READ_REQUEST_ID		1
 #define ATP_GEYSER_MODE_WRITE_REQUEST_ID	9
@@ -213,14 +216,16 @@ struct atp {
 	struct work_struct	work;
 };
 
-#define dbg_dump(msg, tab) \
+#define dbg_dump(msg, tab)						\
+{									\
 	if (debug > 1) {						\
 		int __i;						\
 		printk(KERN_DEBUG "appletouch: %s", msg);		\
 		for (__i = 0; __i < ATP_XSENSORS + ATP_YSENSORS; __i++)	\
 			printk(" %02x", tab[__i]);			\
 		printk("\n");						\
-	}
+	}								\
+}
 
 #define dprintk(format, a...)						\
 	do {								\
@@ -236,14 +241,20 @@ MODULE_AUTHOR("Sven Anders");
 MODULE_DESCRIPTION("Apple PowerBook and MacBook USB touchpad driver");
 MODULE_LICENSE("GPL");
 
-/*
- * Make the threshold a module parameter
- */
-static int threshold = ATP_THRESHOLD;
+static int threshold = -1;
 module_param(threshold, int, 0644);
 MODULE_PARM_DESC(threshold, "Discard any change in data from a sensor"
 			    " (the trackpad has many of these sensors)"
-			    " less than this value.");
+			    " less than this value. Devices have defaults;"
+			    " this parameter overrides them.");
+static int fuzz = -1;
+
+module_param(fuzz, int, 0644);
+MODULE_PARM_DESC(fuzz, "Fuzz the trackpad generates. The higher"
+		       " this is, the less sensitive the trackpad"
+		       " will feel, but values too low may generate"
+		       " random movement. Devices have defaults;"
+		       " this parameter overrides them.");
 
 static int debug;
 module_param(debug, int, 0644);
@@ -363,7 +374,8 @@ static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact,
 		    (!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)) {
+		} else if (i > 0 && (xy_sensors[i - 1] -
+			xy_sensors[i] > threshold)) {
 			is_increasing = 0;
 		}
 
@@ -456,7 +468,7 @@ 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);
+					     fuzz, 0);
 			break;
 		}
 	}
@@ -513,7 +525,8 @@ static void atp_complete_geyser_1_2(struct urb *urb)
 
 			/* Y values */
 			dev->xy_cur[ATP_XSENSORS + i] = dev->data[5 * i +  1];
-			dev->xy_cur[ATP_XSENSORS + i + 8] = dev->data[5 * i + 3];
+			dev->xy_cur[ATP_XSENSORS + i + 8] =
+				dev->data[5 * i + 3];
 		}
 	}
 
@@ -809,12 +822,17 @@ static int atp_probe(struct usb_interface *iface,
 	dev->info = info;
 	dev->overflow_warned = false;
 
+	if (fuzz < 0)
+		fuzz = dev->info->fuzz;
+	if (threshold < 0)
+		threshold = dev->info->threshold;
+
 	dev->urb = usb_alloc_urb(0, GFP_KERNEL);
 	if (!dev->urb)
 		goto err_free_devs;
 
-	dev->data = usb_alloc_coherent(dev->udev, dev->info->datalen, GFP_KERNEL,
-				       &dev->urb->transfer_dma);
+	dev->data = usb_alloc_coherent(dev->udev, dev->info->datalen,
+					GFP_KERNEL, &dev->urb->transfer_dma);
 	if (!dev->data)
 		goto err_free_urb;
 
@@ -844,10 +862,10 @@ 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);
+			     fuzz, 0);
 	input_set_abs_params(input_dev, ABS_Y, 0,
 			     (dev->info->ysensors - 1) * dev->info->yfact - 1,
-			     ATP_FUZZ, 0);
+			     fuzz, 0);
 	input_set_abs_params(input_dev, ABS_PRESSURE, 0, ATP_PRESSURE, 0, 0);
 
 	set_bit(EV_KEY, input_dev->evbit);
-- 
1.7.9.5