Input: byd - add BYD PS/2 touchpad driver

Driver for the BYD BTP10463 touchpad, found in PC Specialist `Lafite'
laptops. This patch sends the magic command sequence which causes the
touchpad to stream intellimouse-style packets.

Gestures are detected inside the touchpad, and exposed as special
values in the Z component of each packet - absolute coordinates are
not supported, even in the Windows driver. At present, this supports
two-finger vertical and horizontal scrolling, and provides the
framework to expose the other gestures it can recognize.

Signed-off-by: Chris Diamand <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/mouse/Kconfig

···
 
 	  If unsure, say Y.
 
+config MOUSE_PS2_BYD
+	bool "BYD PS/2 mouse protocol extension" if EXPERT
+	default y
+	depends on MOUSE_PS2
+	help
+	  Say Y here if you have a BYD PS/2 touchpad connected to
+	  your system.
+
+	  If unsure, say Y.
+
 config MOUSE_PS2_LOGIPS2PP
 	bool "Logitech PS/2++ mouse protocol extension" if EXPERT
 	default y

drivers/input/mouse/Makefile

···
 psmouse-objs := psmouse-base.o synaptics.o focaltech.o
 
 psmouse-$(CONFIG_MOUSE_PS2_ALPS)	+= alps.o
+psmouse-$(CONFIG_MOUSE_PS2_BYD)		+= byd.o
 psmouse-$(CONFIG_MOUSE_PS2_ELANTECH)	+= elantech.o
 psmouse-$(CONFIG_MOUSE_PS2_OLPC)	+= hgpk.o
 psmouse-$(CONFIG_MOUSE_PS2_LOGIPS2PP)	+= logips2pp.o

drivers/input/mouse/byd.c

···
+/*
+ * BYD TouchPad PS/2 mouse driver
+ *
+ * Copyright (C) 2015 Chris Diamand <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/delay.h>
+#include <linux/input.h>
+#include <linux/libps2.h>
+#include <linux/serio.h>
+
+#include "psmouse.h"
+#include "byd.h"
+
+#define PS2_Y_OVERFLOW	BIT_MASK(7)
+#define PS2_X_OVERFLOW	BIT_MASK(6)
+#define PS2_Y_SIGN	BIT_MASK(5)
+#define PS2_X_SIGN	BIT_MASK(4)
+#define PS2_ALWAYS_1	BIT_MASK(3)
+#define PS2_MIDDLE	BIT_MASK(2)
+#define PS2_RIGHT	BIT_MASK(1)
+#define PS2_LEFT	BIT_MASK(0)
+
+/*
+ * The touchpad reports gestures in the last byte of each packet. It can take
+ * any of the following values:
+ */
+
+/* One-finger scrolling in one of the edge scroll zones. */
+#define BYD_SCROLLUP		0xCA
+#define BYD_SCROLLDOWN		0x36
+#define BYD_SCROLLLEFT		0xCB
+#define BYD_SCROLLRIGHT		0x35
+/* Two-finger scrolling. */
+#define BYD_2DOWN		0x2B
+#define BYD_2UP			0xD5
+#define BYD_2LEFT		0xD6
+#define BYD_2RIGHT		0x2A
+/* Pinching in or out. */
+#define BYD_ZOOMOUT		0xD8
+#define BYD_ZOOMIN		0x28
+/* Three-finger swipe. */
+#define BYD_3UP			0xD3
+#define BYD_3DOWN		0x2D
+#define BYD_3LEFT		0xD4
+#define BYD_3RIGHT		0x2C
+/* Four-finger swipe. */
+#define BYD_4UP			0xCD
+#define BYD_4DOWN		0x33
+
+int byd_detect(struct psmouse *psmouse, bool set_properties)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+	unsigned char param[4];
+
+	param[0] = 0x03;
+	param[1] = 0x00;
+	param[2] = 0x00;
+	param[3] = 0x00;
+
+	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;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
+		return -1;
+	if (ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
+		return -1;
+
+	if (param[1] != 0x03 || param[2] != 0x64)
+		return -ENODEV;
+
+	psmouse_dbg(psmouse, "BYD touchpad detected\n");
+
+	if (set_properties) {
+		psmouse->vendor = "BYD";
+		psmouse->name = "TouchPad";
+	}
+
+	return 0;
+}
+
+static psmouse_ret_t byd_process_byte(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	u8 *pkt = psmouse->packet;
+
+	if (psmouse->pktcnt > 0 && !(pkt[0] & PS2_ALWAYS_1)) {
+		psmouse_warn(psmouse, "Always_1 bit not 1. pkt[0] = %02x\n",
+			     pkt[0]);
+		return PSMOUSE_BAD_DATA;
+	}
+
+	if (psmouse->pktcnt < psmouse->pktsize)
+		return PSMOUSE_GOOD_DATA;
+
+	/* Otherwise, a full packet has been received */
+	switch (pkt[3]) {
+	case 0: {
+		/* Standard packet */
+		/* Sign-extend if a sign bit is set. */
+		unsigned int signx = pkt[0] & PS2_X_SIGN ? ~0xFF : 0;
+		unsigned int signy = pkt[0] & PS2_Y_SIGN ? ~0xFF : 0;
+		int dx = signx | (int) pkt[1];
+		int dy = signy | (int) pkt[2];
+
+		input_report_rel(psmouse->dev, REL_X, dx);
+		input_report_rel(psmouse->dev, REL_Y, -dy);
+
+		input_report_key(psmouse->dev, BTN_LEFT, pkt[0] & PS2_LEFT);
+		input_report_key(psmouse->dev, BTN_RIGHT, pkt[0] & PS2_RIGHT);
+		input_report_key(psmouse->dev, BTN_MIDDLE, pkt[0] & PS2_MIDDLE);
+		break;
+	}
+
+	case BYD_SCROLLDOWN:
+	case BYD_2DOWN:
+		input_report_rel(dev, REL_WHEEL, -1);
+		break;
+
+	case BYD_SCROLLUP:
+	case BYD_2UP:
+		input_report_rel(dev, REL_WHEEL, 1);
+		break;
+
+	case BYD_SCROLLLEFT:
+	case BYD_2LEFT:
+		input_report_rel(dev, REL_HWHEEL, -1);
+		break;
+
+	case BYD_SCROLLRIGHT:
+	case BYD_2RIGHT:
+		input_report_rel(dev, REL_HWHEEL, 1);
+		break;
+
+	case BYD_ZOOMOUT:
+	case BYD_ZOOMIN:
+	case BYD_3UP:
+	case BYD_3DOWN:
+	case BYD_3LEFT:
+	case BYD_3RIGHT:
+	case BYD_4UP:
+	case BYD_4DOWN:
+		break;
+
+	default:
+		psmouse_warn(psmouse,
+			     "Unrecognized Z: pkt = %02x %02x %02x %02x\n",
+			     psmouse->packet[0], psmouse->packet[1],
+			     psmouse->packet[2], psmouse->packet[3]);
+		return PSMOUSE_BAD_DATA;
+	}
+
+	input_sync(dev);
+
+	return PSMOUSE_FULL_PACKET;
+}
+
+/* Send a sequence of bytes, where each is ACKed before the next is sent. */
+static int byd_send_sequence(struct psmouse *psmouse, const u8 *seq, size_t len)
+{
+	unsigned int i;
+
+	for (i = 0; i < len; ++i) {
+		if (ps2_command(&psmouse->ps2dev, NULL, seq[i]))
+			return -1;
+	}
+	return 0;
+}
+
+/* Keep scrolling after fingers are removed. */
+#define SCROLL_INERTIAL		0x01
+#define SCROLL_NO_INERTIAL	0x02
+
+/* Clicking can be done by tapping or pressing. */
+#define CLICK_BOTH		0x01
+/* Clicking can only be done by pressing. */
+#define CLICK_PRESS_ONLY	0x02
+
+static int byd_enable(struct psmouse *psmouse)
+{
+	const u8 seq1[] = { 0xE2, 0x00, 0xE0, 0x02, 0xE0 };
+	const u8 seq2[] = {
+		0xD3, 0x01,
+		0xD0, 0x00,
+		0xD0, 0x04,
+		/* Whether clicking is done by tapping or pressing. */
+		0xD4, CLICK_PRESS_ONLY,
+		0xD5, 0x01,
+		0xD7, 0x03,
+		/* Vertical and horizontal one-finger scroll zone inertia. */
+		0xD8, SCROLL_INERTIAL,
+		0xDA, 0x05,
+		0xDB, 0x02,
+		0xE4, 0x05,
+		0xD6, 0x01,
+		0xDE, 0x04,
+		0xE3, 0x01,
+		0xCF, 0x00,
+		0xD2, 0x03,
+		/* Vertical and horizontal two-finger scrolling inertia. */
+		0xE5, SCROLL_INERTIAL,
+		0xD9, 0x02,
+		0xD9, 0x07,
+		0xDC, 0x03,
+		0xDD, 0x03,
+		0xDF, 0x03,
+		0xE1, 0x03,
+		0xD1, 0x00,
+		0xCE, 0x00,
+		0xCC, 0x00,
+		0xE0, 0x00,
+		0xE2, 0x01
+	};
+	u8 param[4];
+
+	if (byd_send_sequence(psmouse, seq1, ARRAY_SIZE(seq1)))
+		return -1;
+
+	/* Send a 0x01 command, which should return 4 bytes. */
+	if (ps2_command(&psmouse->ps2dev, param, 0x0401))
+		return -1;
+
+	if (byd_send_sequence(psmouse, seq2, ARRAY_SIZE(seq2)))
+		return -1;
+
+	return 0;
+}
+
+/*
+ * Send the set of PS/2 commands required to make it identify as an
+ * intellimouse with 4-byte instead of 3-byte packets.
+ */
+static int byd_send_intellimouse_sequence(struct psmouse *psmouse)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+	u8 param[4];
+	int i;
+	const struct {
+		u16 command;
+		u8 arg;
+	} seq[] = {
+		{ PSMOUSE_CMD_RESET_BAT, 0 },
+		{ PSMOUSE_CMD_RESET_BAT, 0 },
+		{ PSMOUSE_CMD_GETID, 0 },
+		{ PSMOUSE_CMD_SETSCALE11, 0 },
+		{ PSMOUSE_CMD_SETSCALE11, 0 },
+		{ PSMOUSE_CMD_SETSCALE11, 0 },
+		{ PSMOUSE_CMD_GETINFO, 0 },
+		{ PSMOUSE_CMD_SETRES, 0x03 },
+		{ PSMOUSE_CMD_SETRATE, 0xC8 },
+		{ PSMOUSE_CMD_SETRATE, 0x64 },
+		{ PSMOUSE_CMD_SETRATE, 0x50 },
+		{ PSMOUSE_CMD_GETID, 0 },
+		{ PSMOUSE_CMD_SETRATE, 0xC8 },
+		{ PSMOUSE_CMD_SETRATE, 0xC8 },
+		{ PSMOUSE_CMD_SETRATE, 0x50 },
+		{ PSMOUSE_CMD_GETID, 0 },
+		{ PSMOUSE_CMD_SETRATE, 0x64 },
+		{ PSMOUSE_CMD_SETRES, 0x03 },
+		{ PSMOUSE_CMD_ENABLE, 0 }
+	};
+
+	memset(param, 0, sizeof(param));
+	for (i = 0; i < ARRAY_SIZE(seq); ++i) {
+		param[0] = seq[i].arg;
+		if (ps2_command(ps2dev, param, seq[i].command))
+			return -1;
+	}
+
+	return 0;
+}
+
+static int byd_reset_touchpad(struct psmouse *psmouse)
+{
+	if (byd_send_intellimouse_sequence(psmouse))
+		return -EIO;
+
+	if (byd_enable(psmouse))
+		return -EIO;
+
+	return 0;
+}
+
+static int byd_reconnect(struct psmouse *psmouse)
+{
+	int retry = 0, error = 0;
+
+	psmouse_dbg(psmouse, "Reconnect\n");
+	do {
+		psmouse_reset(psmouse);
+		if (retry)
+			ssleep(1);
+		error = byd_detect(psmouse, 0);
+	} while (error && ++retry < 3);
+
+	if (error)
+		return error;
+
+	psmouse_dbg(psmouse, "Reconnected after %d attempts\n", retry);
+
+	error = byd_reset_touchpad(psmouse);
+	if (error) {
+		psmouse_err(psmouse, "Unable to initialize device\n");
+		return error;
+	}
+
+	return 0;
+}
+
+int byd_init(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+
+	if (psmouse_reset(psmouse))
+		return -EIO;
+
+	if (byd_reset_touchpad(psmouse))
+		return -EIO;
+
+	psmouse->reconnect = byd_reconnect;
+	psmouse->protocol_handler = byd_process_byte;
+	psmouse->pktsize = 4;
+	psmouse->resync_time = 0;
+
+	__set_bit(BTN_MIDDLE, dev->keybit);
+	__set_bit(REL_WHEEL, dev->relbit);
+	__set_bit(REL_HWHEEL, dev->relbit);
+
+	return 0;
+}

drivers/input/mouse/byd.h

···
+#ifndef _BYD_H
+#define _BYD_H
+
+#ifdef CONFIG_MOUSE_PS2_BYD
+int byd_detect(struct psmouse *psmouse, bool set_properties);
+int byd_init(struct psmouse *psmouse);
+#else
+static inline int byd_detect(struct psmouse *psmouse, bool set_properties)
+{
+	return -ENOSYS;
+}
+static inline int byd_init(struct psmouse *psmouse)
+{
+	return -ENOSYS;
+}
+#endif /* CONFIG_MOUSE_PS2_BYD */
+
+#endif /* _BYD_H */

drivers/input/mouse/psmouse-base.c

···
 #include "cypress_ps2.h"
 #include "focaltech.h"
 #include "vmmouse.h"
+#include "byd.h"
 
 #define DRIVER_DESC	"PS/2 mouse driver"
 
···
 		.init		= vmmouse_init,
 	},
 #endif
+#ifdef CONFIG_MOUSE_PS2_BYD
+	{
+		.type		= PSMOUSE_BYD,
+		.name		= "BydPS/2",
+		.alias		= "byd",
+		.detect		= byd_detect,
+		.init		= byd_init,
+	},
+#endif
 	{
 		.type		= PSMOUSE_AUTO,
 		.name		= "auto",
···
 		if (psmouse_try_protocol(psmouse, PSMOUSE_TOUCHKIT_PS2,
 					 &max_proto, set_properties, true))
 			return PSMOUSE_TOUCHKIT_PS2;
+
+		if (psmouse_try_protocol(psmouse, PSMOUSE_BYD,
+					 &max_proto, set_properties, true))
+			return PSMOUSE_BYD;
 	}
 
 	/*

drivers/input/mouse/psmouse.h

···
 	PSMOUSE_CYPRESS,
 	PSMOUSE_FOCALTECH,
 	PSMOUSE_VMMOUSE,
+	PSMOUSE_BYD,
 	PSMOUSE_AUTO		/* This one should always be last */
 };