path: root/drivers/input/mouse/hgpk.c

/*
 * OLPC HGPK (XO-1) touchpad PS/2 mouse driver
 *
 * Copyright (c) 2006-2008 One Laptop Per Child
 * Authors:
 *   Zephaniah E. Hull
 *   Andres Salomon <dilinger@debian.org>
 *
 * This driver is partly based on the ALPS driver, which is:
 *
 * Copyright (c) 2003 Neil Brown <neilb@cse.unsw.edu.au>
 * Copyright (c) 2003-2005 Peter Osterlund <petero2@telia.com>
 * Copyright (c) 2004 Dmitry Torokhov <dtor@mail.ru>
 * Copyright (c) 2005 Vojtech Pavlik <vojtech@suse.cz>
 *
 * 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.
 */

/*
 * The spec from ALPS is available from
 * <http://wiki.laptop.org/go/Touch_Pad/Tablet>.  It refers to this
 * device as HGPK (Hybrid GS, PT, and Keymatrix).
 *
 * The earliest versions of the device had simultaneous reporting; that
 * was removed.  After that, the device used the Advanced Mode GS/PT streaming
 * stuff.  That turned out to be too buggy to support, so we've finally
 * switched to Mouse Mode (which utilizes only the center 1/3 of the touchpad).
 */

#define DEBUG
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/module.h>
#include <linux/serio.h>
#include <linux/libps2.h>
#include <linux/delay.h>
#include <asm/olpc.h>

#include "psmouse.h"
#include "hgpk.h"

#define ILLEGAL_XY 999999

static bool tpdebug;
module_param(tpdebug, bool, 0644);
MODULE_PARM_DESC(tpdebug, "enable debugging, dumping packets to KERN_DEBUG.");

static int recalib_delta = 100;
module_param(recalib_delta, int, 0644);
MODULE_PARM_DESC(recalib_delta,
	"packets containing a delta this large will be discarded, and a "
	"recalibration may be scheduled.");

static int jumpy_delay = 20;
module_param(jumpy_delay, int, 0644);
MODULE_PARM_DESC(jumpy_delay,
	"delay (ms) before recal after jumpiness detected");

static int spew_delay = 1;
module_param(spew_delay, int, 0644);
MODULE_PARM_DESC(spew_delay,
	"delay (ms) before recal after packet spew detected");

static int recal_guard_time;
module_param(recal_guard_time, int, 0644);
MODULE_PARM_DESC(recal_guard_time,
	"interval (ms) during which recal will be restarted if packet received");

static int post_interrupt_delay = 40;
module_param(post_interrupt_delay, int, 0644);
MODULE_PARM_DESC(post_interrupt_delay,
	"delay (ms) before recal after recal interrupt detected");

static bool autorecal = true;
module_param(autorecal, bool, 0644);
MODULE_PARM_DESC(autorecal, "enable recalibration in the driver");

static char hgpk_mode_name[16];
module_param_string(hgpk_mode, hgpk_mode_name, sizeof(hgpk_mode_name), 0644);
MODULE_PARM_DESC(hgpk_mode,
	"default hgpk mode: mouse, glidesensor or pentablet");

static int hgpk_default_mode = HGPK_MODE_MOUSE;

static const char * const hgpk_mode_names[] = {
	[HGPK_MODE_MOUSE] = "Mouse",
	[HGPK_MODE_GLIDESENSOR] = "GlideSensor",
	[HGPK_MODE_PENTABLET] = "PenTablet",
};

static int hgpk_mode_from_name(const char *buf, int len)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(hgpk_mode_names); i++) {
		const char *name = hgpk_mode_names[i];
		if (strlen(name) == len && !strncasecmp(name, buf, len))
			return i;
	}

	return HGPK_MODE_INVALID;
}

/*
 * see if new value is within 20% of half of old value
 */
static int approx_half(int curr, int prev)
{
	int belowhalf, abovehalf;

	if (curr < 5 || prev < 5)
		return 0;

	belowhalf = (prev * 8) / 20;
	abovehalf = (prev * 12) / 20;

	return belowhalf < curr && curr <= abovehalf;
}

/*
 * Throw out oddly large delta packets, and any that immediately follow whose
 * values are each approximately half of the previous.  It seems that the ALPS
 * firmware emits errant packets, and they get averaged out slowly.
 */
static int hgpk_discard_decay_hack(struct psmouse *psmouse, int x, int y)
{
	struct hgpk_data *priv = psmouse->private;
	int avx, avy;
	bool do_recal = false;

	avx = abs(x);
	avy = abs(y);

	/* discard if too big, or half that but > 4 times the prev delta */
	if (avx > recalib_delta ||
		(avx > recalib_delta / 2 && ((avx / 4) > priv->xlast))) {
		psmouse_warn(psmouse, "detected %dpx jump in x\n", x);
		priv->xbigj = avx;
	} else if (approx_half(avx, priv->xbigj)) {
		psmouse_warn(