Input: trackpoint - Optimize trackpoint init to use power-on reset

The trackpoint driver sets various parameter default values, all of
which happen to be power-on defaults (Source: IBM TrackPoint Engineering
Specification, Version 4.0. Also confirmed by empirical data).

By sending the power-on reset command to reset all parameters to
power-on state, we can skip the lengthy process of programming all
parameters. In testing, ~2.5 secs of time writing parameters was reduced
to .35 seconds waiting for power-on reset to complete.

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

2 files changed, 166 insertions, 87 deletions

diff --git a/drivers/input/mouse/trackpoint.c b/drivers/input/mouse/trackpoint.c
index f310249..ca843b6 100644
--- a/drivers/input/mouse/trackpoint.c
+++ b/drivers/input/mouse/trackpoint.c
@@ -20,9 +20,34 @@
 #include "trackpoint.h"
 
 /*
+ * Power-on Reset: Resets all trackpoint parameters, including RAM values,
+ * to defaults.
+ * Returns zero on success, non-zero on failure.
+ */
+static int trackpoint_power_on_reset(struct ps2dev *ps2dev)
+{
+	unsigned char results[2];
+	int tries = 0;
+
+	/* Issue POR command, and repeat up to once if 0xFC00 received */
+	do {
+		if (ps2_command(ps2dev, NULL, MAKE_PS2_CMD(0, 0, TP_COMMAND)) ||
+		    ps2_command(ps2dev, results, MAKE_PS2_CMD(0, 2, TP_POR)))
+			return -1;
+	} while (results[0] == 0xFC && results[1] == 0x00 && ++tries < 2);
+
+	/* Check for success response -- 0xAA00 */
+	if (results[0] != 0xAA || results[1] != 0x00)
+		return -1;
+
+	return 0;
+}
+
+/*
  * Device IO: read, write and toggle bit
  */
-static int trackpoint_read(struct ps2dev *ps2dev, unsigned char loc, unsigned char *results)
+static int trackpoint_read(struct ps2dev *ps2dev,
+			   unsigned char loc, unsigned char *results)
 {
 	if (ps2_command(ps2dev, NULL, MAKE_PS2_CMD(0, 0, TP_COMMAND)) ||
 	    ps2_command(ps2dev, results, MAKE_PS2_CMD(0, 1, loc))) {
@@ -32,7 +57,8 @@ static int trackpoint_read(struct ps2dev *ps2dev, unsigned char loc, unsigned ch
 	return 0;
 }
 
-static int trackpoint_write(struct ps2dev *ps2dev, unsigned char loc, unsigned char val)
+static int trackpoint_write(struct ps2dev *ps2dev,
+			    unsigned char loc, unsigned char val)
 {
 	if (ps2_command(ps2dev, NULL, MAKE_PS2_CMD(0, 0, TP_COMMAND)) ||
 	    ps2_command(ps2dev, NULL, MAKE_PS2_CMD(0, 0, TP_WRITE_MEM)) ||
@@ -44,7 +70,8 @@ static int trackpoint_write(struct ps2dev *ps2dev, unsigned char loc, unsigned c
 	return 0;
 }
 
-static int trackpoint_toggle_bit(struct ps2dev *ps2dev, unsigned char loc, unsigned char mask)
+static int trackpoint_toggle_bit(struct ps2dev *ps2dev,
+				 unsigned char loc, unsigned char mask)
 {
 	/* Bad things will happen if the loc param isn't in this range */
 	if (loc < 0x20 || loc >= 0x2F)
@@ -60,6 +87,18 @@ static int trackpoint_toggle_bit(struct ps2dev *ps2dev, unsigned char loc, unsig
 	return 0;
 }
 
+static int trackpoint_update_bit(struct ps2dev *ps2dev, unsigned char loc,
+				 unsigned char mask, unsigned char value)
+{
+	int retval = 0;
+	unsigned char data;
+
+	trackpoint_read(ps2dev, loc, &data);
+	if (((data & mask) == mask) != !!value)
+		retval = trackpoint_toggle_bit(ps2dev, loc, mask);
+
+	return retval;
+}
 
 /*
  * Trackpoint-specific attributes
@@ -69,6 +108,7 @@ struct trackpoint_attr_data {
 	unsigned char command;
 	unsigned char mask;
 	unsigned char inverted;
+	unsigned char power_on_default;
 };
 
 static ssize_t trackpoint_show_int_attr(struct psmouse *psmouse, void *data, char *buf)
@@ -102,10 +142,11 @@ static ssize_t trackpoint_set_int_attr(struct psmouse *psmouse, void *data,
 	return count;
 }
 
-#define TRACKPOINT_INT_ATTR(_name, _command)					\
+#define TRACKPOINT_INT_ATTR(_name, _command, _default)				\
 	static struct trackpoint_attr_data trackpoint_attr_##_name = {		\
 		.field_offset = offsetof(struct trackpoint_data, _name),	\
 		.command = _command,						\
+		.power_on_default = _default,					\
 	};									\
 	PSMOUSE_DEFINE_ATTR(_name, S_IWUSR | S_IRUGO,				\
 			    &trackpoint_attr_##_name,				\
@@ -139,31 +180,60 @@ static ssize_t trackpoint_set_bit_attr(struct psmouse *psmouse, void *data,
 }
 
 
-#define TRACKPOINT_BIT_ATTR(_name, _command, _mask, _inv)				\
-	static struct trackpoint_attr_data trackpoint_attr_##_name = {		\
-		.field_offset	= offsetof(struct trackpoint_data, _name),	\
-		.command	= _command,					\
-		.mask		= _mask,					\
-		.inverted	= _inv,						\
-	};									\
-	PSMOUSE_DEFINE_ATTR(_name, S_IWUSR | S_IRUGO,				\
-			    &trackpoint_attr_##_name,				\
-			    trackpoint_show_int_attr, trackpoint_set_bit_attr)
-
-TRACKPOINT_INT_ATTR(sensitivity, TP_SENS);
-TRACKPOINT_INT_ATTR(speed, TP_SPEED);
-TRACKPOINT_INT_ATTR(inertia, TP_INERTIA);
-TRACKPOINT_INT_ATTR(reach, TP_REACH);
-TRACKPOINT_INT_ATTR(draghys, TP_DRAGHYS);
-TRACKPOINT_INT_ATTR(mindrag, TP_MINDRAG);
-TRACKPOINT_INT_ATTR(thresh, TP_THRESH);
-TRACKPOINT_INT_ATTR(upthresh, TP_UP_THRESH);
-TRACKPOINT_INT_ATTR(ztime, TP_Z_TIME);
-TRACKPOINT_INT_ATTR(jenks, TP_JENKS_CURV);
-
-TRACKPOINT_BIT_ATTR(press_to_select, TP_TOGGLE_PTSON, TP_MASK_PTSON, 0);
-TRACKPOINT_BIT_ATTR(skipback, TP_TOGGLE_SKIPBACK, TP_MASK_SKIPBACK, 0);
-TRACKPOINT_BIT_ATTR(ext_dev, TP_TOGGLE_EXT_DEV, TP_MASK_EXT_DEV, 1);
+#define TRACKPOINT_BIT_ATTR(_name, _command, _mask, _inv, _default)	\
+static struct trackpoint_attr_data trackpoint_attr_##_name = {		\
+	.field_offset		= offsetof(struct trackpoint_data,	\
+					   _name),			\
+	.command		= _command,				\
+	.mask			= _mask,				\
+	.inverted		= _inv,					\
+	.power_on_default	= _default,				\
+	};								\
+PSMOUSE_DEFINE_ATTR(_name, S_IWUSR | S_IRUGO,				\
+		    &trackpoint_attr_##_name,				\
+		    trackpoint_show_int_attr, trackpoint_set_bit_attr)
+
+#define TRACKPOINT_UPDATE_BIT(_psmouse, _tp, _name)			\
+do {									\
+	struct trackpoint_attr_data *_attr = &trackpoint_attr_##_name;	\
+									\
+	trackpoint_update_bit(&_psmouse->ps2dev,			\
+			_attr->command, _attr->mask, _tp->_name);	\
+} while (0)
+
+#define TRACKPOINT_UPDATE(_power_on, _psmouse, _tp, _name)		\
+do {									\
+	if (!_power_on ||						\
+	    _tp->_name != trackpoint_attr_##_name.power_on_default) {	\
+		if (!trackpoint_attr_##_name.mask)			\
+			trackpoint_write(&_psmouse->ps2dev,		\
+				 trackpoint_attr_##_name.command,	\
+				 _tp->_name);				\
+		else							\
+			TRACKPOINT_UPDATE_BIT(_psmouse, _tp, _name);	\
+	}								\
+} while (0)
+
+#define TRACKPOINT_SET_POWER_ON_DEFAULT(_tp, _name)				\
+	(_tp->_name = trackpoint_attr_##_name.power_on_default)
+
+TRACKPOINT_INT_ATTR(sensitivity, TP_SENS, TP_DEF_SENS);
+TRACKPOINT_INT_ATTR(speed, TP_SPEED, TP_DEF_SPEED);
+TRACKPOINT_INT_ATTR(inertia, TP_INERTIA, TP_DEF_INERTIA);
+TRACKPOINT_INT_ATTR(reach, TP_REACH, TP_DEF_REACH);
+TRACKPOINT_INT_ATTR(draghys, TP_DRAGHYS, TP_DEF_DRAGHYS);
+TRACKPOINT_INT_ATTR(mindrag, TP_MINDRAG, TP_DEF_MINDRAG);
+TRACKPOINT_INT_ATTR(thresh, TP_THRESH, TP_DEF_THRESH);
+TRACKPOINT_INT_ATTR(upthresh, TP_UP_THRESH, TP_DEF_UP_THRESH);
+TRACKPOINT_INT_ATTR(ztime, TP_Z_TIME, TP_DEF_Z_TIME);
+TRACKPOINT_INT_ATTR(jenks, TP_JENKS_CURV, TP_DEF_JENKS_CURV);
+
+TRACKPOINT_BIT_ATTR(press_to_select, TP_TOGGLE_PTSON, TP_MASK_PTSON, 0,
+		    TP_DEF_PTSON);
+TRACKPOINT_BIT_ATTR(skipback, TP_TOGGLE_SKIPBACK, TP_MASK_SKIPBACK, 0,
+		    TP_DEF_SKIPBACK);
+TRACKPOINT_BIT_ATTR(ext_dev, TP_TOGGLE_EXT_DEV, TP_MASK_EXT_DEV, 1,
+		    TP_DEF_EXT_DEV);
 
 static struct attribute *trackpoint_attrs[] = {
 	&psmouse_attr_sensitivity.dattr.attr,
@@ -202,73 +272,72 @@ static int trackpoint_start_protocol(struct psmouse *psmouse, unsigned char *fir
 	return 0;
 }
 
-static int trackpoint_sync(struct psmouse *psmouse)
+/*
+ * Write parameters to trackpad.
+ * in_power_on_state: Set to true if TP is in default / power-on state (ex. if
+ *		      power-on reset was run). If so, values will only be
+ *		      written to TP if they differ from power-on default.
+ */
+static int trackpoint_sync(struct psmouse *psmouse, bool in_power_on_state)
 {
 	struct trackpoint_data *tp = psmouse->private;
-	unsigned char toggle;
-
-	/* Disable features that may make device unusable with this driver */
-	trackpoint_read(&psmouse->ps2dev, TP_TOGGLE_TWOHAND, &toggle);
-	if (toggle & TP_MASK_TWOHAND)
-		trackpoint_toggle_bit(&psmouse->ps2dev, TP_TOGGLE_TWOHAND, TP_MASK_TWOHAND);
-
-	trackpoint_read(&psmouse->ps2dev, TP_TOGGLE_SOURCE_TAG, &toggle);
-	if (toggle & TP_MASK_SOURCE_TAG)
-		trackpoint_toggle_bit(&psmouse->ps2dev, TP_TOGGLE_SOURCE_TAG, TP_MASK_SOURCE_TAG);
-
-	trackpoint_read(&psmouse->ps2dev, TP_TOGGLE_MB, &toggle);
-	if (toggle & TP_MASK_MB)
-		trackpoint_toggle_bit(&psmouse->ps2dev, TP_TOGGLE_MB, TP_MASK_MB);
-
-	/* Push the config to the device */
-	trackpoint_write(&psmouse->ps2dev, TP_SENS, tp->sensitivity);
-	trackpoint_write(&psmouse->ps2dev, TP_INERTIA, tp->inertia);
-	trackpoint_write(&psmouse->ps2dev, TP_SPEED, tp->speed);
-
-	trackpoint_write(&psmouse->ps2dev, TP_REACH, tp->reach);
-	trackpoint_write(&psmouse->ps2dev, TP_DRAGHYS, tp->draghys);
-	trackpoint_write(&psmouse->ps2dev, TP_MINDRAG, tp->mindrag);
-
-	trackpoint_write(&psmouse->ps2dev, TP_THRESH, tp->thresh);
-	trackpoint_write(&psmouse->ps2dev, TP_UP_THRESH, tp->upthresh);
 
-	trackpoint_write(&psmouse->ps2dev, TP_Z_TIME, tp->ztime);
-	trackpoint_write(&psmouse->ps2dev, TP_JENKS_CURV, tp->jenks);
+	if (!in_power_on_state) {
+		/*
+		 * Disable features that may make device unusable
+		 * with this driver.
+		 */
+		trackpoint_update_bit(&psmouse->ps2dev, TP_TOGGLE_TWOHAND,
+				      TP_MASK_TWOHAND, TP_DEF_TWOHAND);
 
-	trackpoint_read(&psmouse->ps2dev, TP_TOGGLE_PTSON, &toggle);
-	if (((toggle & TP_MASK_PTSON) == TP_MASK_PTSON) != tp->press_to_select)
-		 trackpoint_toggle_bit(&psmouse->ps2dev, TP_TOGGLE_PTSON, TP_MASK_PTSON);
+		trackpoint_update_bit(&psmouse->ps2dev, TP_TOGGLE_SOURCE_TAG,
+				      TP_MASK_SOURCE_TAG, TP_DEF_SOURCE_TAG);
 
-	trackpoint_read(&psmouse->ps2dev, TP_TOGGLE_SKIPBACK, &toggle);
-	if (((toggle & TP_MASK_SKIPBACK) == TP_MASK_SKIPBACK) != tp->skipback)
-		trackpoint_toggle_bit(&psmouse->ps2dev, TP_TOGGLE_SKIPBACK, TP_MASK_SKIPBACK);
+		trackpoint_update_bit(&psmouse->ps2dev, TP_TOGGLE_MB,
+				      TP_MASK_MB, TP_DEF_MB);
+	}
 
-	trackpoint_read(&psmouse->ps2dev, TP_TOGGLE_EXT_DEV, &toggle);
-	if (((toggle & TP_MASK_EXT_DEV) == TP_MASK_EXT_DEV) != tp->ext_dev)
-		trackpoint_toggle_bit(&psmouse->ps2dev, TP_TOGGLE_EXT_DEV, TP_MASK_EXT_DEV);
+	/*
+	 * These properties can be changed in this driver. Only
+	 * configure them if the values are non-default or if the TP is in
+	 * an unknown state.
+	 */
+	TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, sensitivity);
+	TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, inertia);
+	TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, speed);
+	TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, reach);
+	TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, draghys);
+	TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, mindrag);
+	TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, thresh);
+	TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, upthresh);
+	TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, ztime);
+	TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, jenks);
+
+	/* toggles */
+	TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, press_to_select);
+	TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, skipback);
+	TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, ext_dev);
 
 	return 0;
 }
 
 static void trackpoint_defaults(struct trackpoint_data *tp)
 {
-	tp->press_to_select = TP_DEF_PTSON;
-	tp->sensitivity = TP_DEF_SENS;
-	tp->speed = TP_DEF_SPEED;
-	tp->reach = TP_DEF_REACH;
-
-	tp->draghys = TP_DEF_DRAGHYS;
-	tp->mindrag = TP_DEF_MINDRAG;
-
-	tp->thresh = TP_DEF_THRESH;
-	tp->upthresh = TP_DEF_UP_THRESH;
-
-	tp->ztime = TP_DEF_Z_TIME;
-	tp->jenks = TP_DEF_JENKS_CURV;
-
-	tp->inertia = TP_DEF_INERTIA;
-	tp->skipback = TP_DEF_SKIPBACK;
-	tp->ext_dev = TP_DEF_EXT_DEV;
+	TRACKPOINT_SET_POWER_ON_DEFAULT(tp, sensitivity);
+	TRACKPOINT_SET_POWER_ON_DEFAULT(tp, speed);
+	TRACKPOINT_SET_POWER_ON_DEFAULT(tp, reach);
+	TRACKPOINT_SET_POWER_ON_DEFAULT(tp, draghys);
+	TRACKPOINT_SET_POWER_ON_DEFAULT(tp, mindrag);
+	TRACKPOINT_SET_POWER_ON_DEFAULT(tp, thresh);
+	TRACKPOINT_SET_POWER_ON_DEFAULT(tp, upthresh);
+	TRACKPOINT_SET_POWER_ON_DEFAULT(tp, ztime);
+	TRACKPOINT_SET_POWER_ON_DEFAULT(tp, jenks);
+	TRACKPOINT_SET_POWER_ON_DEFAULT(tp, inertia);
+
+	/* toggles */
+	TRACKPOINT_SET_POWER_ON_DEFAULT(tp, press_to_select);
+	TRACKPOINT_SET_POWER_ON_DEFAULT(tp, skipback);
+	TRACKPOINT_SET_POWER_ON_DEFAULT(tp, ext_dev);
 }
 
 static void trackpoint_disconnect(struct psmouse *psmouse)
@@ -281,10 +350,13 @@ static void trackpoint_disconnect(struct psmouse *psmouse)
 
 static int trackpoint_reconnect(struct psmouse *psmouse)
 {
+	int reset_fail;
+
 	if (trackpoint_start_protocol(psmouse, NULL))
 		return -1;
 
-	if (trackpoint_sync(psmouse))
+	reset_fail = trackpoint_power_on_reset(&psmouse->ps2dev);
+	if (trackpoint_sync(psmouse, !reset_fail))
 		return -1;
 
 	return 0;
@@ -322,7 +394,12 @@ int trackpoint_detect(struct psmouse *psmouse, bool set_properties)
 		__set_bit(BTN_MIDDLE, psmouse->dev->keybit);
 
 	trackpoint_defaults(psmouse->private);
-	trackpoint_sync(psmouse);
+
+	error = trackpoint_power_on_reset(&psmouse->ps2dev);
+
+	/* Write defaults to TP only if reset fails. */
+	if (error)
+		trackpoint_sync(psmouse, false);
 
 	error = sysfs_create_group(&ps2dev->serio->dev.kobj, &trackpoint_attr_group);
 	if (error) {
diff --git a/drivers/input/mouse/trackpoint.h b/drivers/input/mouse/trackpoint.h
index e558a70..ecd0547 100644
--- a/drivers/input/mouse/trackpoint.h
+++ b/drivers/input/mouse/trackpoint.h
@@ -126,6 +126,8 @@
 #define TP_DEF_PTSON		0x00
 #define TP_DEF_SKIPBACK		0x00
 #define TP_DEF_EXT_DEV		0x00	/* 0 means enabled */
+#define TP_DEF_TWOHAND		0x00
+#define TP_DEF_SOURCE_TAG	0x00
 
 #define MAKE_PS2_CMD(params, results, cmd) ((params<<12) | (results<<8) | (cmd))
 
@@ -136,9 +138,9 @@ struct trackpoint_data
 	unsigned char thresh, upthresh;
 	unsigned char ztime, jenks;
 
+	/* toggles */
 	unsigned char press_to_select;
 	unsigned char skipback;
-
 	unsigned char ext_dev;
 };