psmouse: Add some support for the FocalTech PS/2 protocol extensions.

Most of the protocol for these touchpads has been reverse engineered. This commit adds a basic multitouch-capable driver.

A lot of the protocol is still unknown. Especially, we don't know how to identify the device yet apart from the PNP ID.

The previous workaround for these devices has been left in place in case the driver is not compiled into the kernel or in case some other device with the same PNP ID is not recognized by the driver yet still has the same
problems with the device probing code.

---

(Sorry, some serious incompetence caused me to always test an old version of the module, so I overlooked an embarrasing pagefault right during initialization, where memory allocation did not happen early enough)

Thanks for the first round of review, I hope I addressed all comments. Changes compared to the last version:
- The detection code does not compare all registers anymore.
- The driver now reads the size of the touchpad during initialization. This should add support for Asus X450JN, where the touchpad is a bit wider.
- set_input_params has been simplified.
- fingers are now valid=0 when the touchpad reports a large object.

 drivers/input/mouse/Kconfig        |  10 ++
 drivers/input/mouse/focaltech.c    | 300

++++++++++++++++++++++++++++++++++++-

 drivers/input/mouse/focaltech.h    |  60 ++++++++
 drivers/input/mouse/psmouse-base.c |  32 ++--
 drivers/input/mouse/psmouse.h      |   1 +
 5 files changed, 386 insertions(+), 17 deletions(-)

drivers/input/mouse/Kconfig +9 -0

index 366fc7a..db973e5 100644
@@ -146,6 +146,16 @@ config MOUSE_PS2_OLPC
  	  If unsure, say N.
 +config MOUSE_PS2_FOCALTECH
+	bool "FocalTech PS/2 mouse protocol extension" if EXPERT
+	default y
+	depends on MOUSE_PS2
+	help
+	  Say Y here if you have a FocalTech PS/2 TouchPad connected to
+	  your system.
+
+	  If unsure, say Y.
+
 config MOUSE_SERIAL
 	tristate "Serial mouse"
 	select SERIO

drivers/input/mouse/focaltech.c +1 -1

index f4d657e..26bc5b7 100644
@@ -2,6 +2,7 @@
  * Focaltech TouchPad PS/2 mouse driver
  *
  * Copyright (c) 2014 Red Hat Inc.
+ * Copyright (c) 2014 Mathias Gottschlag <[email protected]>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by

@@ -13,15 +14,14 @@
  * Hans de Goede <[email protected]>
  */
 -/*
- * The Focaltech PS/2 touchpad protocol is unknown. This drivers

deals with
- * detection only, to avoid further detection attempts confusing the touchpad
- * this way it at least works in PS/2 mouse compatibility mode.
- */
#include <linux/device.h>
#include <linux/libps2.h>

drivers/input/mouse/focaltech.c +5 -0

+#include <linux/input/mt.h>
+#include <linux/serio.h>
+#include <linux/slab.h>
 #include "psmouse.h"
+#include "focaltech.h"
  static const char * const focaltech_pnp_ids[] = {
 	"FLT0101",

@@ -30,6 +30,12 @@ static const char * const focaltech_pnp_ids[] = {
 	NULL
 };
 +/*
+ * Even if the kernel is built without support for Focaltech PS/2

touchpads (or
+ * when the real driver fails to recognize the device), we still have to detect
+ * them in order to avoid further detection attempts confusing the touchpad.
+ * This way it at least works in PS/2 mouse compatibility mode.
+ */
int focaltech_detect(struct psmouse *psmouse, bool set_properties) {

drivers/input/mouse/focaltech.c +207 -1

 	if (!psmouse_matches_pnp_id(psmouse, focaltech_pnp_ids))

@@ -37,16 +43,296 @@ int focaltech_detect(struct psmouse *psmouse,
 bool set_properties)
  	if (set_properties) {
 		psmouse->vendor = "FocalTech";
-		psmouse->name = "FocalTech Touchpad in mouse emulation mode";
+		psmouse->name = "FocalTech Touchpad";
 	}
  	return 0;
 }
 -int focaltech_init(struct psmouse *psmouse)
+static void focaltech_reset(struct psmouse *psmouse)
 {
 	ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_RESET_DIS);
 	psmouse_reset(psmouse);
+}
+
+#ifdef CONFIG_MOUSE_PS2_FOCALTECH
+
+static void focaltech_report_state(struct psmouse *psmouse)
+{
+	int i;
+	struct focaltech_data *priv = psmouse->private;
+	struct focaltech_hw_state *state = &priv->state;
+	struct input_dev *dev = psmouse->dev;
+	int finger_count = 0;
+
+	for (i = 0; i < FOC_MAX_FINGERS; i++) {
+		struct focaltech_finger_state *finger = &state->fingers[i];
+		int active = finger->active && finger->valid;
+		input_mt_slot(dev, i);
+		input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
+		if (active) {
+			finger_count++;
+			input_report_abs(dev, ABS_MT_POSITION_X, finger->x);
+			input_report_abs(dev, ABS_MT_POSITION_Y,
+					focaltech_invert_y(finger->y));
+		}
+	}
+	input_mt_report_pointer_emulation(dev, finger_count);
+
+	input_report_key(psmouse->dev, BTN_LEFT, state->pressed);
+	input_sync(psmouse->dev);
+}
+
+static void process_touch_packet(struct focaltech_hw_state *state,
+		unsigned char *packet)
+{
+	int i;
+	unsigned char fingers = packet[1];
+
+	state->pressed = (packet[0] >> 4) & 1;
+	/* the second byte contains a bitmap of all fingers touching the pad */
+	for (i = 0; i < FOC_MAX_FINGERS; i++) {
+		if ((fingers & 0x1) && !state->fingers[i].active) {
+			/* we do not have a valid position for the finger yet */
+			state->fingers[i].valid = 0;
+		}
+		state->fingers[i].active = fingers & 0x1;
+		fingers >>= 1;
+	}
+}
+
+static void process_abs_packet(struct focaltech_hw_state *state,
+		unsigned char *packet)
+{
+	unsigned int finger = (packet[1] >> 4) - 1;
+
+	state->pressed = (packet[0] >> 4) & 1;
+	if (finger >= FOC_MAX_FINGERS)
+		return;
+	/*
+	 * packet[5] contains some kind of tool size in the most significant
+	 * nibble. 0xff is a special value (latching) that signals a large
+	 * contact area.
+	 */
+	if (packet[5] == 0xff) {
+		state->fingers[finger].valid = 0;
+		return;
+	}
+	state->fingers[finger].x = ((packet[1] & 0xf) << 8) | packet[2];
+	state->fingers[finger].y = (packet[3] << 8) | packet[4];
+	state->fingers[finger].valid = 1;
+}
+static void process_rel_packet(struct focaltech_hw_state *state,
+		unsigned char *packet)
+{
+	int finger1 = ((packet[0] >> 4) & 0x7) - 1;
+	int finger2 = ((packet[3] >> 4) & 0x7) - 1;
+
+	state->pressed = packet[0] >> 7;
+	if (finger1 < FOC_MAX_FINGERS) {
+		state->fingers[finger1].x += (char)packet[1];
+		state->fingers[finger1].y += (char)packet[2];
+	}
+	/*
+	 * If there is an odd number of fingers, the last relative packet only
+	 * contains one finger. In this case, the second finger index in the
+	 * packet is 0 (we subtract 1 in the lines above to create array
+	 * indices).
+	 */
+	if (finger2 != -1 && finger2 < FOC_MAX_FINGERS) {
+		state->fingers[finger2].x += (char)packet[4];
+		state->fingers[finger2].y += (char)packet[5];
+	}
+}
+
+static void focaltech_process_packet(struct psmouse *psmouse)
+{
+	struct focaltech_data *priv = psmouse->private;
+	unsigned char *packet = psmouse->packet;
+
+	switch (packet[0] & 0xf) {
+	case FOC_TOUCH:
+		process_touch_packet(&priv->state, packet);
+		break;
+	case FOC_ABS:
+		process_abs_packet(&priv->state, packet);
+		break;
+	case FOC_REL:
+		process_rel_packet(&priv->state, packet);
+		break;
+	default:
+		psmouse_err(psmouse, "Unknown packet type: %02x", packet[0]);
+		break;
+	}
+
+	focaltech_report_state(psmouse);
+}
+
+static psmouse_ret_t focaltech_process_byte(struct psmouse *psmouse)
+{
+	if (psmouse->pktcnt >= 6) { /* Full packet received */
+		focaltech_process_packet(psmouse);
+		return PSMOUSE_FULL_PACKET;
+	}
+	/*
+	 * we might want to do some validation of the data here, but we do not
+	 * know the protocoll well enough
+	 */
+	return PSMOUSE_GOOD_DATA;
+}
+
+static int focaltech_switch_protocol(struct psmouse *psmouse)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+	unsigned char param[3];
+
+	param[0] = 0;
+	if (ps2_command(ps2dev, param, 0x10f8))
+		return -EIO;
+	if (ps2_command(ps2dev, param, 0x10f8))
+		return -EIO;
+	if (ps2_command(ps2dev, param, 0x10f8))
+		return -EIO;
+	param[0] = 1;
+	if (ps2_command(ps2dev, param, 0x10f8))
+		return -EIO;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETSCALE11))
+		return -EIO;
+
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_ENABLE))
+		return -EIO;
  	return 0;
 }
+
+static void focaltech_disconnect(struct psmouse *psmouse)
+{
+	focaltech_reset(psmouse);
+	kfree(psmouse->private);
+	psmouse->private = NULL;
+}
+
+static int focaltech_reconnect(struct psmouse *psmouse)
+{
+	focaltech_reset(psmouse);
+	if (focaltech_switch_protocol(psmouse)) {
+		psmouse_err(psmouse,
+			    "Unable to initialize the device.");
+		return -1;
+	}
+	return 0;
+}
+
+static void set_input_params(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	struct focaltech_data *priv = psmouse->private;
+
+	__set_bit(EV_ABS, dev->evbit);
+	input_set_abs_params(dev, ABS_MT_POSITION_X, 0, priv->x_max, 0, 0);
+	input_set_abs_params(dev, ABS_MT_POSITION_Y, 0, priv->y_max, 0, 0);
+	input_mt_init_slots(dev, 5, INPUT_MT_POINTER);
+	__clear_bit(EV_REL, dev->evbit);
+	__clear_bit(REL_X, dev->relbit);
+	__clear_bit(REL_Y, dev->relbit);
+	__clear_bit(BTN_RIGHT, dev->keybit);
+	__clear_bit(BTN_MIDDLE, dev->keybit);
+	__set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
+}
+
+static int focaltech_read_register(struct ps2dev *ps2dev, int reg,
+		unsigned char *param)
+{
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETSCALE11))
+		return -1;
+	param[0] = 0;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -1;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -1;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -1;
+	param[0] = reg;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -1;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
+		return -1;
+	return 0;
+}
+
+static int focaltech_read_size(struct psmouse *psmouse)

drivers/input/mouse/focaltech.c +65 -0

+
+	return 0;
+}
+int focaltech_init(struct psmouse *psmouse)
+{
+	struct focaltech_data *priv;
+	int err;
+
+	psmouse->private = priv = kzalloc(sizeof(struct focaltech_data),
 GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	focaltech_reset(psmouse);
+	if (focaltech_read_size(psmouse)) {
+		focaltech_reset(psmouse);
+		psmouse_err(psmouse,
+			    "Unable to read the size of the touchpad.");
+		err = -ENOSYS;
+		goto fail;
+	}
+	if (focaltech_switch_protocol(psmouse)) {
+		focaltech_reset(psmouse);
+		psmouse_err(psmouse,
+			    "Unable to initialize the device.");
+		err = -ENOSYS;
+		goto fail;
+	}
+
+	set_input_params(psmouse);
+
+	psmouse->protocol_handler = focaltech_process_byte;
+	psmouse->pktsize = 6;
+	psmouse->disconnect = focaltech_disconnect;
+	psmouse->reconnect = focaltech_reconnect;
+	psmouse->cleanup = focaltech_reset;
+	/* resync is not supported yet */
+	psmouse->resync_time = 0;
+
+	return 0;
+fail:
+	focaltech_reset(psmouse);
+	kfree(priv);
+	return err;
+}
+
+bool focaltech_supported(void)
+{
+	return true;
+}
+
+#else /* CONFIG_MOUSE_PS2_FOCALTECH */
+
+int focaltech_init(struct psmouse *psmouse)
+{
+	focaltech_reset(psmouse);
+
+	return 0;
+}
+
+bool focaltech_supported(void)
+{
+	return false;
+}
+
+#endif /* CONFIG_MOUSE_PS2_FOCALTECH */

drivers/input/mouse/focaltech.h +59 -0

index 498650c..68c5cfc 100644
@@ -2,6 +2,7 @@
  * Focaltech TouchPad PS/2 mouse driver
  *
  * Copyright (c) 2014 Red Hat Inc.
+ * Copyright (c) 2014 Mathias Gottschlag <[email protected]>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by

@@ -16,7 +17,66 @@
 #ifndef _FOCALTECH_H
 #define _FOCALTECH_H
 +/*
+ * Packet types - the numbers are not consecutive, so we might be missing
+ * something here.
+ */
+#define FOC_TOUCH 0x3 /* bitmap of active fingers */
+#define FOC_ABS 0x6 /* absolute position of one finger */
+#define FOC_REL 0x9 /* relative position of 1-2 fingers */
+
+#define FOC_MAX_FINGERS 5
+
+#define FOC_MAX_X 2431
+#define FOC_MAX_Y 1663
+
+static inline int focaltech_invert_y(int y)
+{
+	return FOC_MAX_Y - y;
+}
+
+/*
+ * Current state of a single finger on the touchpad.
+ */
+struct focaltech_finger_state {
+	/* the touchpad has generated a touch event for the finger */
+	bool active;
+	/*
+	 * The touchpad has sent position data for the finger. Touch event
+	 * packages reset this flag for new fingers, and there is a time
+	 * between the first touch event and the following absolute position
+	 * packet for the finger where the touchpad has declared the finger to
+	 * be valid, but we do not have any valid position yet.
+	 */
+	bool valid;
+	/* absolute position (from the bottom left corner) of the finger */
+	unsigned int x;
+	unsigned int y;
+};
+
+/*
+ * Description of the current state of the touchpad hardware.
+ */
+struct focaltech_hw_state {
+	/*
+	 * The touchpad tracks the positions of the fingers for us, the array
+	 * indices correspond to the finger indices returned in the report
+	 * packages.
+	 */
+	struct focaltech_finger_state fingers[FOC_MAX_FINGERS];
+	/*
+	 * True if the clickpad has been pressed.
+	 */
+	bool pressed;
+};
+
+struct focaltech_data {
+	unsigned int x_max, y_max;
+	struct focaltech_hw_state state;
+};
+
 int focaltech_detect(struct psmouse *psmouse, bool set_properties);
 int focaltech_init(struct psmouse *psmouse);
+bool focaltech_supported(void);
  #endif

drivers/input/mouse/psmouse-base.c +0 -0

index 26994f6..4a9de33 100644
@@ -725,16 +725,19 @@ static int psmouse_extensions(struct psmouse
 *psmouse,
  /* Always check for focaltech, this is safe as it uses pnp-id

matching */

drivers/input/mouse/psmouse-base.c +13 -10

 	if (psmouse_do_detect(focaltech_detect, psmouse, set_properties) == 0) {
-		if (!set_properties || focaltech_init(psmouse) == 0) {
-			/*
-			 * Not supported yet, use bare protocol.
-			 * Note that we need to also restrict
-			 * psmouse_max_proto so that psmouse_initialize()
-			 * does not try to reset rate and resolution,
-			 * because even that upsets the device.
-			 */
-			psmouse_max_proto = PSMOUSE_PS2;
-			return PSMOUSE_PS2;
+		if (max_proto > PSMOUSE_IMEX) {
+			if (!set_properties || focaltech_init(psmouse) == 0) {
+				if (focaltech_supported())
+					return PSMOUSE_FOCALTECH;
+				/*
+				 * Note that we need to also restrict
+				 * psmouse_max_proto so that psmouse_initialize()
+				 * does not try to reset rate and resolution,
+				 * because even that upsets the device.
+				 */
+				psmouse_max_proto = PSMOUSE_PS2;
+				return PSMOUSE_PS2;
+			}
 		}
 	}
 @@ -1063,6 +1066,15 @@ static const struct psmouse_protocol

psmouse_protocols[] = {

drivers/input/mouse/psmouse-base.c +9 -0

 		.alias		= "cortps",
 		.detect		= cortron_detect,
 	},
+#ifdef CONFIG_MOUSE_PS2_FOCALTECH
+	{
+		.type		= PSMOUSE_FOCALTECH,
+		.name		= "FocalTechPS/2",
+		.alias		= "focaltech",
+		.detect		= focaltech_detect,
+		.init		= focaltech_init,
+	},
+#endif
 	{
 		.type		= PSMOUSE_AUTO,
 		.name		= "auto",

drivers/input/mouse/psmouse.h +0 -0

index f4cf664..c2ff137 100644

Hi Mathias,

Thanks for your continued work on this. 3 remarks online + 1 at the bottom.

Quoted 11 lines · Mathias Gottschlag

Most of the protocol for these touchpads has been reverse engineered. This commit adds a basic multitouch-capable driver.

A lot of the protocol is still unknown. Especially, we don't know how to identify the device yet apart from the PNP ID.

The previous workaround for these devices has been left in place in case the driver is not compiled into the kernel or in case some other device with the same PNP ID is not recognized by the driver yet still has the same
problems with the device probing code.

Missing "Signed-off-by: Mathias Gottschlag <[email protected]>", we need this before this patch can be merged (just put it at the end of the commit message (official end, before the changelog) when you send the next version).

Quoted 16 lines

---

(Sorry, some serious incompetence caused me to always test an old version of the module, so I overlooked an embarrasing pagefault right during initialization, where memory allocation did not happen early enough)

Thanks for the first round of review, I hope I addressed all comments. Changes compared to the last version:
- The detection code does not compare all registers anymore.
- The driver now reads the size of the touchpad during initialization. This should add support for Asus X450JN, where the touchpad is a bit wider.
- set_input_params has been simplified.
- fingers are now valid=0 when the touchpad reports a large object.

Quoted 3 lines

 drivers/input/mouse/Kconfig        |  10 ++
 drivers/input/mouse/focaltech.c    | 300

++++++++++++++++++++++++++++++++++++-

Your mail client has line-wrapped this line, and many others further below, making it impossible to apply this, please resend using "git send-email" .

Quoted 296 lines

 drivers/input/mouse/focaltech.h    |  60 ++++++++
 drivers/input/mouse/psmouse-base.c |  32 ++--
 drivers/input/mouse/psmouse.h      |   1 +
 5 files changed, 386 insertions(+), 17 deletions(-)

drivers/input/mouse/Kconfig +9 -0

index 366fc7a..db973e5 100644
@@ -146,6 +146,16 @@ config MOUSE_PS2_OLPC
  	  If unsure, say N.
 +config MOUSE_PS2_FOCALTECH
+	bool "FocalTech PS/2 mouse protocol extension" if EXPERT
+	default y
+	depends on MOUSE_PS2
+	help
+	  Say Y here if you have a FocalTech PS/2 TouchPad connected to
+	  your system.
+
+	  If unsure, say Y.
+
 config MOUSE_SERIAL
 	tristate "Serial mouse"
 	select SERIO

drivers/input/mouse/focaltech.c +1 -1

index f4d657e..26bc5b7 100644
@@ -2,6 +2,7 @@
  * Focaltech TouchPad PS/2 mouse driver
  *
  * Copyright (c) 2014 Red Hat Inc.
+ * Copyright (c) 2014 Mathias Gottschlag <[email protected]>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by

@@ -13,15 +14,14 @@
  * Hans de Goede <[email protected]>
  */
 -/*
- * The Focaltech PS/2 touchpad protocol is unknown. This drivers

deals with
- * detection only, to avoid further detection attempts confusing the touchpad
- * this way it at least works in PS/2 mouse compatibility mode.
- */
#include <linux/device.h>
#include <linux/libps2.h>

drivers/input/mouse/focaltech.c +5 -0

+#include <linux/input/mt.h>
+#include <linux/serio.h>
+#include <linux/slab.h>
 #include "psmouse.h"
+#include "focaltech.h"
  static const char * const focaltech_pnp_ids[] = {
 	"FLT0101",

@@ -30,6 +30,12 @@ static const char * const focaltech_pnp_ids[] = {
 	NULL
 };
 +/*
+ * Even if the kernel is built without support for Focaltech PS/2

touchpads (or
+ * when the real driver fails to recognize the device), we still have to detect
+ * them in order to avoid further detection attempts confusing the touchpad.
+ * This way it at least works in PS/2 mouse compatibility mode.
+ */
int focaltech_detect(struct psmouse *psmouse, bool set_properties) {

drivers/input/mouse/focaltech.c +211 -1

 	if (!psmouse_matches_pnp_id(psmouse, focaltech_pnp_ids))

@@ -37,16 +43,296 @@ int focaltech_detect(struct psmouse *psmouse,
 bool set_properties)
  	if (set_properties) {
 		psmouse->vendor = "FocalTech";
-		psmouse->name = "FocalTech Touchpad in mouse emulation mode";
+		psmouse->name = "FocalTech Touchpad";
 	}
  	return 0;
 }
 -int focaltech_init(struct psmouse *psmouse)
+static void focaltech_reset(struct psmouse *psmouse)
 {
 	ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_RESET_DIS);
 	psmouse_reset(psmouse);
+}
+
+#ifdef CONFIG_MOUSE_PS2_FOCALTECH
+
+static void focaltech_report_state(struct psmouse *psmouse)
+{
+	int i;
+	struct focaltech_data *priv = psmouse->private;
+	struct focaltech_hw_state *state = &priv->state;
+	struct input_dev *dev = psmouse->dev;
+	int finger_count = 0;
+
+	for (i = 0; i < FOC_MAX_FINGERS; i++) {
+		struct focaltech_finger_state *finger = &state->fingers[i];
+		int active = finger->active && finger->valid;
+		input_mt_slot(dev, i);
+		input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
+		if (active) {
+			finger_count++;
+			input_report_abs(dev, ABS_MT_POSITION_X, finger->x);
+			input_report_abs(dev, ABS_MT_POSITION_Y,
+					focaltech_invert_y(finger->y));
+		}
+	}
+	input_mt_report_pointer_emulation(dev, finger_count);
+
+	input_report_key(psmouse->dev, BTN_LEFT, state->pressed);
+	input_sync(psmouse->dev);
+}
+
+static void process_touch_packet(struct focaltech_hw_state *state,
+		unsigned char *packet)
+{
+	int i;
+	unsigned char fingers = packet[1];
+
+	state->pressed = (packet[0] >> 4) & 1;
+	/* the second byte contains a bitmap of all fingers touching the pad */
+	for (i = 0; i < FOC_MAX_FINGERS; i++) {
+		if ((fingers & 0x1) && !state->fingers[i].active) {
+			/* we do not have a valid position for the finger yet */
+			state->fingers[i].valid = 0;
+		}
+		state->fingers[i].active = fingers & 0x1;
+		fingers >>= 1;
+	}
+}
+
+static void process_abs_packet(struct focaltech_hw_state *state,
+		unsigned char *packet)
+{
+	unsigned int finger = (packet[1] >> 4) - 1;
+
+	state->pressed = (packet[0] >> 4) & 1;
+	if (finger >= FOC_MAX_FINGERS)
+		return;
+	/*
+	 * packet[5] contains some kind of tool size in the most significant
+	 * nibble. 0xff is a special value (latching) that signals a large
+	 * contact area.
+	 */
+	if (packet[5] == 0xff) {
+		state->fingers[finger].valid = 0;
+		return;
+	}
+	state->fingers[finger].x = ((packet[1] & 0xf) << 8) | packet[2];
+	state->fingers[finger].y = (packet[3] << 8) | packet[4];
+	state->fingers[finger].valid = 1;
+}
+static void process_rel_packet(struct focaltech_hw_state *state,
+		unsigned char *packet)
+{
+	int finger1 = ((packet[0] >> 4) & 0x7) - 1;
+	int finger2 = ((packet[3] >> 4) & 0x7) - 1;
+
+	state->pressed = packet[0] >> 7;
+	if (finger1 < FOC_MAX_FINGERS) {
+		state->fingers[finger1].x += (char)packet[1];
+		state->fingers[finger1].y += (char)packet[2];
+	}
+	/*
+	 * If there is an odd number of fingers, the last relative packet only
+	 * contains one finger. In this case, the second finger index in the
+	 * packet is 0 (we subtract 1 in the lines above to create array
+	 * indices).
+	 */
+	if (finger2 != -1 && finger2 < FOC_MAX_FINGERS) {
+		state->fingers[finger2].x += (char)packet[4];
+		state->fingers[finger2].y += (char)packet[5];
+	}
+}
+
+static void focaltech_process_packet(struct psmouse *psmouse)
+{
+	struct focaltech_data *priv = psmouse->private;
+	unsigned char *packet = psmouse->packet;
+
+	switch (packet[0] & 0xf) {
+	case FOC_TOUCH:
+		process_touch_packet(&priv->state, packet);
+		break;
+	case FOC_ABS:
+		process_abs_packet(&priv->state, packet);
+		break;
+	case FOC_REL:
+		process_rel_packet(&priv->state, packet);
+		break;
+	default:
+		psmouse_err(psmouse, "Unknown packet type: %02x", packet[0]);
+		break;
+	}
+
+	focaltech_report_state(psmouse);
+}
+
+static psmouse_ret_t focaltech_process_byte(struct psmouse *psmouse)
+{
+	if (psmouse->pktcnt >= 6) { /* Full packet received */
+		focaltech_process_packet(psmouse);
+		return PSMOUSE_FULL_PACKET;
+	}
+	/*
+	 * we might want to do some validation of the data here, but we do not
+	 * know the protocoll well enough
+	 */
+	return PSMOUSE_GOOD_DATA;
+}
+
+static int focaltech_switch_protocol(struct psmouse *psmouse)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+	unsigned char param[3];
+
+	param[0] = 0;
+	if (ps2_command(ps2dev, param, 0x10f8))
+		return -EIO;
+	if (ps2_command(ps2dev, param, 0x10f8))
+		return -EIO;
+	if (ps2_command(ps2dev, param, 0x10f8))
+		return -EIO;
+	param[0] = 1;
+	if (ps2_command(ps2dev, param, 0x10f8))
+		return -EIO;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETSCALE11))
+		return -EIO;
+
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_ENABLE))
+		return -EIO;
  	return 0;
 }
+
+static void focaltech_disconnect(struct psmouse *psmouse)
+{
+	focaltech_reset(psmouse);
+	kfree(psmouse->private);
+	psmouse->private = NULL;
+}
+
+static int focaltech_reconnect(struct psmouse *psmouse)
+{
+	focaltech_reset(psmouse);
+	if (focaltech_switch_protocol(psmouse)) {
+		psmouse_err(psmouse,
+			    "Unable to initialize the device.");
+		return -1;
+	}
+	return 0;
+}
+
+static void set_input_params(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	struct focaltech_data *priv = psmouse->private;
+
+	__set_bit(EV_ABS, dev->evbit);
+	input_set_abs_params(dev, ABS_MT_POSITION_X, 0, priv->x_max, 0, 0);
+	input_set_abs_params(dev, ABS_MT_POSITION_Y, 0, priv->y_max, 0, 0);
+	input_mt_init_slots(dev, 5, INPUT_MT_POINTER);
+	__clear_bit(EV_REL, dev->evbit);
+	__clear_bit(REL_X, dev->relbit);
+	__clear_bit(REL_Y, dev->relbit);
+	__clear_bit(BTN_RIGHT, dev->keybit);
+	__clear_bit(BTN_MIDDLE, dev->keybit);
+	__set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
+}
+
+static int focaltech_read_register(struct ps2dev *ps2dev, int reg,
+		unsigned char *param)
+{
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETSCALE11))
+		return -1;
+	param[0] = 0;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -1;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -1;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -1;
+	param[0] = reg;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -1;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
+		return -1;
+	return 0;
+}
+
+static int focaltech_read_size(struct psmouse *psmouse)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+	struct focaltech_data *priv = psmouse->private;
+	char param[3];

drivers/input/mouse/focaltech.c int focaltech_detect(struct psmouse *psmouse, · line 271

Quoted 6 lines

drivers/input/mouse/focaltech.c +6 -0

+
+	if (focaltech_read_register(ps2dev, 2, param))
+		return -EIO;
+	/* not sure whether this is 100% correct */
+	priv->x_max = (unsigned char)param[1] * 128;
+	priv->y_max = (unsigned char)param[2] * 128;

Hmm, I assume it is 99% correct for the X450 and X550 ? In that case this is good enough for now.

Quoted 203 lines

drivers/input/mouse/focaltech.c +65 -0

+
+	return 0;
+}
+int focaltech_init(struct psmouse *psmouse)
+{
+	struct focaltech_data *priv;
+	int err;
+
+	psmouse->private = priv = kzalloc(sizeof(struct focaltech_data),
 GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	focaltech_reset(psmouse);
+	if (focaltech_read_size(psmouse)) {
+		focaltech_reset(psmouse);
+		psmouse_err(psmouse,
+			    "Unable to read the size of the touchpad.");
+		err = -ENOSYS;
+		goto fail;
+	}
+	if (focaltech_switch_protocol(psmouse)) {
+		focaltech_reset(psmouse);
+		psmouse_err(psmouse,
+			    "Unable to initialize the device.");
+		err = -ENOSYS;
+		goto fail;
+	}
+
+	set_input_params(psmouse);
+
+	psmouse->protocol_handler = focaltech_process_byte;
+	psmouse->pktsize = 6;
+	psmouse->disconnect = focaltech_disconnect;
+	psmouse->reconnect = focaltech_reconnect;
+	psmouse->cleanup = focaltech_reset;
+	/* resync is not supported yet */
+	psmouse->resync_time = 0;
+
+	return 0;
+fail:
+	focaltech_reset(psmouse);
+	kfree(priv);
+	return err;
+}
+
+bool focaltech_supported(void)
+{
+	return true;
+}
+
+#else /* CONFIG_MOUSE_PS2_FOCALTECH */
+
+int focaltech_init(struct psmouse *psmouse)
+{
+	focaltech_reset(psmouse);
+
+	return 0;
+}
+
+bool focaltech_supported(void)
+{
+	return false;
+}
+
+#endif /* CONFIG_MOUSE_PS2_FOCALTECH */

drivers/input/mouse/focaltech.h +59 -0

index 498650c..68c5cfc 100644
@@ -2,6 +2,7 @@
  * Focaltech TouchPad PS/2 mouse driver
  *
  * Copyright (c) 2014 Red Hat Inc.
+ * Copyright (c) 2014 Mathias Gottschlag <[email protected]>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by

@@ -16,7 +17,66 @@
 #ifndef _FOCALTECH_H
 #define _FOCALTECH_H
 +/*
+ * Packet types - the numbers are not consecutive, so we might be missing
+ * something here.
+ */
+#define FOC_TOUCH 0x3 /* bitmap of active fingers */
+#define FOC_ABS 0x6 /* absolute position of one finger */
+#define FOC_REL 0x9 /* relative position of 1-2 fingers */
+
+#define FOC_MAX_FINGERS 5
+
+#define FOC_MAX_X 2431
+#define FOC_MAX_Y 1663
+
+static inline int focaltech_invert_y(int y)
+{
+	return FOC_MAX_Y - y;
+}
+
+/*
+ * Current state of a single finger on the touchpad.
+ */
+struct focaltech_finger_state {
+	/* the touchpad has generated a touch event for the finger */
+	bool active;
+	/*
+	 * The touchpad has sent position data for the finger. Touch event
+	 * packages reset this flag for new fingers, and there is a time
+	 * between the first touch event and the following absolute position
+	 * packet for the finger where the touchpad has declared the finger to
+	 * be valid, but we do not have any valid position yet.
+	 */
+	bool valid;
+	/* absolute position (from the bottom left corner) of the finger */
+	unsigned int x;
+	unsigned int y;
+};
+
+/*
+ * Description of the current state of the touchpad hardware.
+ */
+struct focaltech_hw_state {
+	/*
+	 * The touchpad tracks the positions of the fingers for us, the array
+	 * indices correspond to the finger indices returned in the report
+	 * packages.
+	 */
+	struct focaltech_finger_state fingers[FOC_MAX_FINGERS];
+	/*
+	 * True if the clickpad has been pressed.
+	 */
+	bool pressed;
+};
+
+struct focaltech_data {
+	unsigned int x_max, y_max;
+	struct focaltech_hw_state state;
+};
+
 int focaltech_detect(struct psmouse *psmouse, bool set_properties);
 int focaltech_init(struct psmouse *psmouse);
+bool focaltech_supported(void);
  #endif

drivers/input/mouse/psmouse-base.c +0 -0

index 26994f6..4a9de33 100644
@@ -725,16 +725,19 @@ static int psmouse_extensions(struct psmouse
 *psmouse,
  /* Always check for focaltech, this is safe as it uses pnp-id

matching */

drivers/input/mouse/psmouse-base.c +13 -10

 	if (psmouse_do_detect(focaltech_detect, psmouse, set_properties) == 0) {
-		if (!set_properties || focaltech_init(psmouse) == 0) {
-			/*
-			 * Not supported yet, use bare protocol.
-			 * Note that we need to also restrict
-			 * psmouse_max_proto so that psmouse_initialize()
-			 * does not try to reset rate and resolution,
-			 * because even that upsets the device.
-			 */
-			psmouse_max_proto = PSMOUSE_PS2;
-			return PSMOUSE_PS2;
+		if (max_proto > PSMOUSE_IMEX) {
+			if (!set_properties || focaltech_init(psmouse) == 0) {
+				if (focaltech_supported())
+					return PSMOUSE_FOCALTECH;
+				/*
+				 * Note that we need to also restrict
+				 * psmouse_max_proto so that psmouse_initialize()
+				 * does not try to reset rate and resolution,
+				 * because even that upsets the device.
+				 */
+				psmouse_max_proto = PSMOUSE_PS2;
+				return PSMOUSE_PS2;
+			}
 		}
 	}
 @@ -1063,6 +1066,15 @@ static const struct psmouse_protocol

psmouse_protocols[] = {

drivers/input/mouse/psmouse-base.c +9 -0

 		.alias		= "cortps",
 		.detect		= cortron_detect,
 	},
+#ifdef CONFIG_MOUSE_PS2_FOCALTECH
+	{
+		.type		= PSMOUSE_FOCALTECH,
+		.name		= "FocalTechPS/2",
+		.alias		= "focaltech",
+		.detect		= focaltech_detect,
+		.init		= focaltech_init,
+	},
+#endif
 	{
 		.type		= PSMOUSE_AUTO,
 		.name		= "auto",

drivers/input/mouse/psmouse.h +0 -0

index f4cf664..c2ff137 100644

drivers/input/mouse/psmouse.h enum psmouse_type { · line 102

Quoted 7 lines

drivers/input/mouse/psmouse.h +1 -0

@@ -96,6 +96,7 @@ enum psmouse_type {
 	PSMOUSE_FSP,
 	PSMOUSE_SYNAPTICS_RELATIVE,
 	PSMOUSE_CYPRESS,
+	PSMOUSE_FOCALTECH,
 	PSMOUSE_AUTO		/* This one should always be last */
 };
 -- 1.9.1

Overall looks good, assuming the answer to my question about x_max / y_max is "yes", then you may add:

Reviewed-by Hans de Goede <[email protected]>

After your Signed-off-by when you submit v4 (we need a v4 because of the line wrapping issue).

Regards,

Hans

Am 31.10.2014 um 14:29 schrieb Hans de Goede:

Quoted 339 lines

Hi Mathias,

Thanks for your continued work on this. 3 remarks online + 1 at the bottom.

Quoted 11 lines · Mathias Gottschlag

Most of the protocol for these touchpads has been reverse engineered. This commit adds a basic multitouch-capable driver.

A lot of the protocol is still unknown. Especially, we don't know how to identify the device yet apart from the PNP ID.

The previous workaround for these devices has been left in place in case the driver is not compiled into the kernel or in case some other device with the same PNP ID is not recognized by the driver yet still has the same
problems with the device probing code.

Missing "Signed-off-by: Mathias Gottschlag <[email protected]>", we need this before this patch can be merged (just put it at the end of the commit message (official end, before the changelog) when you send the next version).

Quoted 16 lines

---

(Sorry, some serious incompetence caused me to always test an old version of the module, so I overlooked an embarrasing pagefault right during initialization, where memory allocation did not happen early enough)

Thanks for the first round of review, I hope I addressed all comments. Changes compared to the last version:
- The detection code does not compare all registers anymore.
- The driver now reads the size of the touchpad during initialization. This should add support for Asus X450JN, where the touchpad is a bit wider.
- set_input_params has been simplified.
- fingers are now valid=0 when the touchpad reports a large object.

Quoted 3 lines

 drivers/input/mouse/Kconfig        |  10 ++
 drivers/input/mouse/focaltech.c    | 300

++++++++++++++++++++++++++++++++++++-

Your mail client has line-wrapped this line, and many others further below, making it impossible to apply this, please resend using "git send-email" .

Quoted 296 lines

 drivers/input/mouse/focaltech.h    |  60 ++++++++
 drivers/input/mouse/psmouse-base.c |  32 ++--
 drivers/input/mouse/psmouse.h      |   1 +
 5 files changed, 386 insertions(+), 17 deletions(-)

drivers/input/mouse/Kconfig +9 -0

index 366fc7a..db973e5 100644
@@ -146,6 +146,16 @@ config MOUSE_PS2_OLPC
  	  If unsure, say N.
 +config MOUSE_PS2_FOCALTECH
+	bool "FocalTech PS/2 mouse protocol extension" if EXPERT
+	default y
+	depends on MOUSE_PS2
+	help
+	  Say Y here if you have a FocalTech PS/2 TouchPad connected to
+	  your system.
+
+	  If unsure, say Y.
+
 config MOUSE_SERIAL
 	tristate "Serial mouse"
 	select SERIO

drivers/input/mouse/focaltech.c +1 -1

index f4d657e..26bc5b7 100644
@@ -2,6 +2,7 @@
  * Focaltech TouchPad PS/2 mouse driver
  *
  * Copyright (c) 2014 Red Hat Inc.
+ * Copyright (c) 2014 Mathias Gottschlag <[email protected]>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by

@@ -13,15 +14,14 @@
  * Hans de Goede <[email protected]>
  */
 -/*
- * The Focaltech PS/2 touchpad protocol is unknown. This drivers

deals with
- * detection only, to avoid further detection attempts confusing the touchpad
- * this way it at least works in PS/2 mouse compatibility mode.
- */
#include <linux/device.h>
#include <linux/libps2.h>

drivers/input/mouse/focaltech.c +5 -0

+#include <linux/input/mt.h>
+#include <linux/serio.h>
+#include <linux/slab.h>
 #include "psmouse.h"
+#include "focaltech.h"
  static const char * const focaltech_pnp_ids[] = {
 	"FLT0101",

@@ -30,6 +30,12 @@ static const char * const focaltech_pnp_ids[] = {
 	NULL
 };
 +/*
+ * Even if the kernel is built without support for Focaltech PS/2

touchpads (or
+ * when the real driver fails to recognize the device), we still have to detect
+ * them in order to avoid further detection attempts confusing the touchpad.
+ * This way it at least works in PS/2 mouse compatibility mode.
+ */
int focaltech_detect(struct psmouse *psmouse, bool set_properties) {

drivers/input/mouse/focaltech.c +211 -1

 	if (!psmouse_matches_pnp_id(psmouse, focaltech_pnp_ids))

@@ -37,16 +43,296 @@ int focaltech_detect(struct psmouse *psmouse,
 bool set_properties)
  	if (set_properties) {
 		psmouse->vendor = "FocalTech";
-		psmouse->name = "FocalTech Touchpad in mouse emulation mode";
+		psmouse->name = "FocalTech Touchpad";
 	}
  	return 0;
 }
 -int focaltech_init(struct psmouse *psmouse)
+static void focaltech_reset(struct psmouse *psmouse)
 {
 	ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_RESET_DIS);
 	psmouse_reset(psmouse);
+}
+
+#ifdef CONFIG_MOUSE_PS2_FOCALTECH
+
+static void focaltech_report_state(struct psmouse *psmouse)
+{
+	int i;
+	struct focaltech_data *priv = psmouse->private;
+	struct focaltech_hw_state *state = &priv->state;
+	struct input_dev *dev = psmouse->dev;
+	int finger_count = 0;
+
+	for (i = 0; i < FOC_MAX_FINGERS; i++) {
+		struct focaltech_finger_state *finger = &state->fingers[i];
+		int active = finger->active && finger->valid;
+		input_mt_slot(dev, i);
+		input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
+		if (active) {
+			finger_count++;
+			input_report_abs(dev, ABS_MT_POSITION_X, finger->x);
+			input_report_abs(dev, ABS_MT_POSITION_Y,
+					focaltech_invert_y(finger->y));
+		}
+	}
+	input_mt_report_pointer_emulation(dev, finger_count);
+
+	input_report_key(psmouse->dev, BTN_LEFT, state->pressed);
+	input_sync(psmouse->dev);
+}
+
+static void process_touch_packet(struct focaltech_hw_state *state,
+		unsigned char *packet)
+{
+	int i;
+	unsigned char fingers = packet[1];
+
+	state->pressed = (packet[0] >> 4) & 1;
+	/* the second byte contains a bitmap of all fingers touching the pad */
+	for (i = 0; i < FOC_MAX_FINGERS; i++) {
+		if ((fingers & 0x1) && !state->fingers[i].active) {
+			/* we do not have a valid position for the finger yet */
+			state->fingers[i].valid = 0;
+		}
+		state->fingers[i].active = fingers & 0x1;
+		fingers >>= 1;
+	}
+}
+
+static void process_abs_packet(struct focaltech_hw_state *state,
+		unsigned char *packet)
+{
+	unsigned int finger = (packet[1] >> 4) - 1;
+
+	state->pressed = (packet[0] >> 4) & 1;
+	if (finger >= FOC_MAX_FINGERS)
+		return;
+	/*
+	 * packet[5] contains some kind of tool size in the most significant
+	 * nibble. 0xff is a special value (latching) that signals a large
+	 * contact area.
+	 */
+	if (packet[5] == 0xff) {
+		state->fingers[finger].valid = 0;
+		return;
+	}
+	state->fingers[finger].x = ((packet[1] & 0xf) << 8) | packet[2];
+	state->fingers[finger].y = (packet[3] << 8) | packet[4];
+	state->fingers[finger].valid = 1;
+}
+static void process_rel_packet(struct focaltech_hw_state *state,
+		unsigned char *packet)
+{
+	int finger1 = ((packet[0] >> 4) & 0x7) - 1;
+	int finger2 = ((packet[3] >> 4) & 0x7) - 1;
+
+	state->pressed = packet[0] >> 7;
+	if (finger1 < FOC_MAX_FINGERS) {
+		state->fingers[finger1].x += (char)packet[1];
+		state->fingers[finger1].y += (char)packet[2];
+	}
+	/*
+	 * If there is an odd number of fingers, the last relative packet only
+	 * contains one finger. In this case, the second finger index in the
+	 * packet is 0 (we subtract 1 in the lines above to create array
+	 * indices).
+	 */
+	if (finger2 != -1 && finger2 < FOC_MAX_FINGERS) {
+		state->fingers[finger2].x += (char)packet[4];
+		state->fingers[finger2].y += (char)packet[5];
+	}
+}
+
+static void focaltech_process_packet(struct psmouse *psmouse)
+{
+	struct focaltech_data *priv = psmouse->private;
+	unsigned char *packet = psmouse->packet;
+
+	switch (packet[0] & 0xf) {
+	case FOC_TOUCH:
+		process_touch_packet(&priv->state, packet);
+		break;
+	case FOC_ABS:
+		process_abs_packet(&priv->state, packet);
+		break;
+	case FOC_REL:
+		process_rel_packet(&priv->state, packet);
+		break;
+	default:
+		psmouse_err(psmouse, "Unknown packet type: %02x", packet[0]);
+		break;
+	}
+
+	focaltech_report_state(psmouse);
+}
+
+static psmouse_ret_t focaltech_process_byte(struct psmouse *psmouse)
+{
+	if (psmouse->pktcnt >= 6) { /* Full packet received */
+		focaltech_process_packet(psmouse);
+		return PSMOUSE_FULL_PACKET;
+	}
+	/*
+	 * we might want to do some validation of the data here, but we do not
+	 * know the protocoll well enough
+	 */
+	return PSMOUSE_GOOD_DATA;
+}
+
+static int focaltech_switch_protocol(struct psmouse *psmouse)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+	unsigned char param[3];
+
+	param[0] = 0;
+	if (ps2_command(ps2dev, param, 0x10f8))
+		return -EIO;
+	if (ps2_command(ps2dev, param, 0x10f8))
+		return -EIO;
+	if (ps2_command(ps2dev, param, 0x10f8))
+		return -EIO;
+	param[0] = 1;
+	if (ps2_command(ps2dev, param, 0x10f8))
+		return -EIO;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETSCALE11))
+		return -EIO;
+
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_ENABLE))
+		return -EIO;
  	return 0;
 }
+
+static void focaltech_disconnect(struct psmouse *psmouse)
+{
+	focaltech_reset(psmouse);
+	kfree(psmouse->private);
+	psmouse->private = NULL;
+}
+
+static int focaltech_reconnect(struct psmouse *psmouse)
+{
+	focaltech_reset(psmouse);
+	if (focaltech_switch_protocol(psmouse)) {
+		psmouse_err(psmouse,
+			    "Unable to initialize the device.");
+		return -1;
+	}
+	return 0;
+}
+
+static void set_input_params(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	struct focaltech_data *priv = psmouse->private;
+
+	__set_bit(EV_ABS, dev->evbit);
+	input_set_abs_params(dev, ABS_MT_POSITION_X, 0, priv->x_max, 0, 0);
+	input_set_abs_params(dev, ABS_MT_POSITION_Y, 0, priv->y_max, 0, 0);
+	input_mt_init_slots(dev, 5, INPUT_MT_POINTER);
+	__clear_bit(EV_REL, dev->evbit);
+	__clear_bit(REL_X, dev->relbit);
+	__clear_bit(REL_Y, dev->relbit);
+	__clear_bit(BTN_RIGHT, dev->keybit);
+	__clear_bit(BTN_MIDDLE, dev->keybit);
+	__set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
+}
+
+static int focaltech_read_register(struct ps2dev *ps2dev, int reg,
+		unsigned char *param)
+{
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETSCALE11))
+		return -1;
+	param[0] = 0;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -1;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -1;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -1;
+	param[0] = reg;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -1;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
+		return -1;
+	return 0;
+}
+
+static int focaltech_read_size(struct psmouse *psmouse)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+	struct focaltech_data *priv = psmouse->private;
+	char param[3];

Quoted 8 lines

drivers/input/mouse/focaltech.c int focaltech_detect(struct psmouse *psmouse, · line 271

Quoted 6 lines

drivers/input/mouse/focaltech.c +6 -0

+
+	if (focaltech_read_register(ps2dev, 2, param))
+		return -EIO;
+	/* not sure whether this is 100% correct */
+	priv->x_max = (unsigned char)param[1] * 128;
+	priv->y_max = (unsigned char)param[2] * 128;

Hmm, I assume it is 99% correct for the X450 and X550 ? In that case this is good enough for now.

It seems to be correct for Asus R405LD, X450, K750 (=X750?), UX303. Good enough, or should I wait for more feedback?