Input: psmouse - 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.
Signed-off-by: Mathias Gottschlag <mgottschlag@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/Kconfig

@@ -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

@@ -2,6 +2,7 @@
  * Focaltech TouchPad PS/2 mouse driver
  *
  * Copyright (c) 2014 Red Hat Inc.
+ * Copyright (c) 2014 Mathias Gottschlag <mgottschlag@gmail.com>
  *
  * 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 <hdegoede@redhat.com>
  */
 
-/*
- * 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>
+#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)
 {
 	if (!psmouse_matches_pnp_id(psmouse, focaltech_pnp_ids))
@@ -37,16 +43,404 @@ 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
+
+/*
+ * 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
+
+/*
+ * 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. The
+	 * flag is 0 when the finger is not active, and there is a
+	 * time between the first touch event for the finger 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;
+};
+
+static void focaltech_report_state(struct psmouse *psmouse)
+{
+	struct focaltech_data *priv = psmouse->private;
+	struct focaltech_hw_state *state = &priv->state;
+	struct input_dev *dev = psmouse->dev;
+	int i;
+
+	for (i = 0; i < FOC_MAX_FINGERS; i++) {
+		struct focaltech_finger_state *finger = &state->fingers[i];
+		bool active = finger->active && finger->valid;
+
+		input_mt_slot(dev, i);
+		input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
+		if (active) {
+			input_report_abs(dev, ABS_MT_POSITION_X, finger->x);
+			input_report_abs(dev, ABS_MT_POSITION_Y,
+					 FOC_MAX_Y - finger->y);
+		}
+	}
+	input_mt_report_pointer_emulation(dev, true);
+
+	input_report_key(psmouse->dev, BTN_LEFT, state->pressed);
+	input_sync(psmouse->dev);
+}
+
+static void focaltech_process_touch_packet(struct psmouse *psmouse,
+					   unsigned char *packet)
+{
+	struct focaltech_data *priv = psmouse->private;
+	struct focaltech_hw_state *state = &priv->state;
+	unsigned char fingers = packet[1];
+	int i;
+
+	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++) {
+		state->fingers[i].active = fingers & 0x1;
+		if (!state->fingers[i].active) {
+			/*
+			 * Even when the finger becomes active again, we still
+			 * will have to wait for the first valid position.
+			 */
+			state->fingers[i].valid = false;
+		}
+		fingers >>= 1;
+	}
+}
+
+static void focaltech_process_abs_packet(struct psmouse *psmouse,
+					 unsigned char *packet)
+{
+	struct focaltech_data *priv = psmouse->private;
+	struct focaltech_hw_state *state = &priv->state;
+	unsigned int finger;
+
+	finger = (packet[1] >> 4) - 1;
+	if (finger >= FOC_MAX_FINGERS) {
+		psmouse_err(psmouse, "Invalid finger in abs packet: %d\n",
+			    finger);
+		return;
+	}
+
+	state->pressed = (packet[0] >> 4) & 1;
+
+	/*
+	 * 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 = false;
+		return;
+	}
+
+	state->fingers[finger].x = ((packet[1] & 0xf) << 8) | packet[2];
+	state->fingers[finger].y = (packet[3] << 8) | packet[4];
+	state->fingers[finger].valid = true;
+}
+
+static void focaltech_process_rel_packet(struct psmouse *psmouse,
+					 unsigned char *packet)
+{
+	struct focaltech_data *priv = psmouse->private;
+	struct focaltech_hw_state *state = &priv->state;
+	int finger1, finger2;
+
+	state->pressed = packet[0] >> 7;
+	finger1 = ((packet[0] >> 4) & 0x7) - 1;
+	if (finger1 < FOC_MAX_FINGERS) {
+		state->fingers[finger1].x += (char)packet[1];
+		state->fingers[finger1].y += (char)packet[2];
+	} else {
+		psmouse_err(psmouse, "First finger in rel packet invalid: %d\n",
+			    finger1);
+	}
+
+	/*
+	 * 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, so the finger will overflow
+	 * and be above FOC_MAX_FINGERS).
+	 */
+	finger2 = ((packet[3] >> 4) & 0x7) - 1;
+	if (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)
+{
+	unsigned char *packet = psmouse->packet;
+
+	switch (packet[0] & 0xf) {
+	case FOC_TOUCH:
+		focaltech_process_touch_packet(psmouse, packet);
+		break;
+
+	case FOC_ABS:
+		focaltech_process_abs_packet(psmouse, packet);
+		break;
+
+	case FOC_REL:
+		focaltech_process_rel_packet(psmouse, packet);
+		break;
+
+	default:
+		psmouse_err(psmouse, "Unknown packet type: %02x\n", 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 protocol 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)
+{
+	int error;
+
+	focaltech_reset(psmouse);
+
+	error = focaltech_switch_protocol(psmouse);
+	if (error) {
+		psmouse_err(psmouse, "Unable to initialize the device\n");
+		return error;
+	}
+
+	return 0;
+}
+
+static void focaltech_set_input_params(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	struct focaltech_data *priv = psmouse->private;
+
+	/*
+	 * Undo part of setup done for us by psmouse core since touchpad
+	 * is not a relative device.
+	 */
+	__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);
+
+	/*
+	 * Now set up our capabilities.
+	 */
+	__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);
+	__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 -EIO;
+
+	param[0] = 0;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -EIO;
+
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -EIO;
+
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -EIO;
+
+	param[0] = reg;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -EIO;
+
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
+		return -EIO;
+
+	return 0;
+}
+
+static int focaltech_read_size(struct psmouse *psmouse)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+	struct focaltech_data *priv = psmouse->private;
+	char param[3];
+
+	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;
+
+	return 0;
+}
+int focaltech_init(struct psmouse *psmouse)
+{
+	struct focaltech_data *priv;
+	int error;
+
+	psmouse->private = priv = kzalloc(sizeof(struct focaltech_data),
+					  GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	focaltech_reset(psmouse);
+
+	error = focaltech_read_size(psmouse);
+	if (error) {
+		psmouse_err(psmouse,
+			    "Unable to read the size of the touchpad\n");
+		goto fail;
+	}
+
+	error = focaltech_switch_protocol(psmouse);
+	if (error) {
+		psmouse_err(psmouse, "Unable to initialize the device\n");
+		goto fail;
+	}
+
+	focaltech_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 error;
 }
+
+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

@@ -2,6 +2,7 @@
  * Focaltech TouchPad PS/2 mouse driver
  *
  * Copyright (c) 2014 Red Hat Inc.
+ * Copyright (c) 2014 Mathias Gottschlag <mgottschlag@gmail.com>
  *
  * 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
@@ -18,5 +19,6 @@
 
 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

@@ -725,16 +725,19 @@ static int psmouse_extensions(struct psmouse *psmouse,
 
 /* Always check for focaltech, this is safe as it uses pnp-id matching */
 	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[] = {
 		.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

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