Input: psmouse - add OLPC touchpad driver

This adds support for OLPC's touchpad.  It has lots of neat features,
none of which are enabled because the hardware is too buggy.  Instead,
we use it like a normal touchpad, but with a number of workarounds in
place to deal with the frequent hardware spasms.  Humidity changes,
sweat, tinfoil underwear, plugging in AC, drinks, evil felines.. All
tend to cause the touchpad to freak out.

Signed-off-by: Andres Salomon <dilinger@debian.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 477 insertions, 0 deletions

diff --git a/drivers/input/mouse/hgpk.c b/drivers/input/mouse/hgpk.c
new file mode 100644
index 00000000000..e82d34201e9
--- /dev/null
+++ b/drivers/input/mouse/hgpk.c
@@ -0,0 +1,477 @@
+/*
+ * 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/input.h>
+#include <linux/serio.h>
+#include <linux/libps2.h>
+#include <linux/delay.h>
+#include <asm/olpc.h>
+
+#include "psmouse.h"
+#include "hgpk.h"
+
+static int tpdebug;
+module_param(tpdebug, int, 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 cause a recalibration.");
+
+/*
+ * When the touchpad gets ultra-sensitive, one can keep their finger 1/2"
+ * above the pad and still have it send packets.  This causes a jump cursor
+ * when one places their finger on the pad.  We can probably detect the
+ * jump as we see a large deltas (>= 100px).  In mouse mode, I've been
+ * unable to even come close to 100px deltas during normal usage, so I think
+ * this threshold is safe.  If a large delta occurs, trigger a recalibration.
+ */
+static void hgpk_jumpy_hack(struct psmouse *psmouse, int x, int y)
+{
+	struct hgpk_data *priv = psmouse->private;
+
+	if (abs(x) > recalib_delta || abs(y) > recalib_delta) {
+		hgpk_err(psmouse, ">%dpx jump detected (%d,%d)\n",
+				recalib_delta, x, y);
+		/* My car gets forty rods to the hogshead and that's the
+		 * way I likes it! */
+		psmouse_queue_work(psmouse, &priv->recalib_wq,
+				msecs_to_jiffies(1000));
+	}
+}
+
+/*
+ * We have no idea why this particular hardware bug occurs.  The touchpad
+ * will randomly start spewing packets without anything touching the
+ * pad.  This wouldn't necessarily be bad, but it's indicative of a
+ * severely miscalibrated pad; attempting to use the touchpad while it's
+ * spewing means the cursor will jump all over the place, and act "drunk".
+ *
+ * The packets that are spewed tend to all have deltas between -2 and 2, and
+ * the cursor will move around without really going very far.  It will
+ * tend to end up in the same location; if we tally up the changes over
+ * 100 packets, we end up w/ a final delta of close to 0.  This happens
+ * pretty regularly when the touchpad is spewing, and is pretty hard to
+ * manually trigger (at least for *my* fingers).  So, it makes a perfect
+ * scheme for detecting spews.
+ */
+static void hgpk_spewing_hack(struct psmouse *psmouse,
+			      int l, int r, int x, int y)
+{
+	struct hgpk_data *priv = psmouse->private;
+
+	/* ignore button press packets; many in a row could trigger
+	 * a false-positive! */
+	if (l || r)
+		return;
+
+	priv->x_tally += x;
+	priv->y_tally += y;
+
+	if (++priv->count > 100) {
+		if (abs(priv->x_tally) < 3 && abs(priv->y_tally) < 3) {
+			hgpk_dbg(psmouse, "packet spew detected (%d,%d)\n",
+				 priv->x_tally, priv->y_tally);
+			psmouse_queue_work(psmouse, &priv->recalib_wq,
+					   msecs_to_jiffies(1000));
+		}
+		/* reset every 100 packets */
+		priv->count = 0;
+		priv->x_tally = 0;
+		priv->y_tally = 0;
+	}
+}
+
+/*
+ * HGPK Mouse Mode format (standard mouse format, sans middle button)
+ *
+ * byte 0:	y-over	x-over	y-neg	x-neg	1	0	swr	swl
+ * byte 1:	x7	x6	x5	x4	x3	x2	x1	x0
+ * byte 2:	y7	y6	y5	y4	y3	y2	y1	y0
+ *
+ * swr/swl are the left/right buttons.
+ * x-neg/y-neg are the x and y delta negative bits
+ * x-over/y-over are the x and y overflow bits
+ */
+static int hgpk_validate_byte(unsigned char *packet)
+{
+	return (packet[0] & 0x0C) == 0x08;
+}
+
+static void hgpk_process_packet(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	unsigned char *packet = psmouse->packet;
+	int x, y, left, right;
+
+	left = packet[0] & 1;
+	right = (packet[0] >> 1) & 1;
+
+	x = packet[1] - ((packet[0] << 4) & 0x100);
+	y = ((packet[0] << 3) & 0x100) - packet[2];
+
+	hgpk_jumpy_hack(psmouse, x, y);
+	hgpk_spewing_hack(psmouse, left, right, x, y);
+
+	if (tpdebug)
+		hgpk_dbg(psmouse, "l=%d r=%d x=%d y=%d\n", left, right, x, y);
+
+	input_report_key(dev, BTN_LEFT, left);
+	input_report_key(dev, BTN_RIGHT, right);
+
+	input_report_rel(dev, REL_X, x);
+	input_report_rel(dev, REL_Y, y);
+
+	input_sync(dev);
+}
+
+static psmouse_ret_t hgpk_process_byte(struct psmouse *psmouse)
+{
+	struct hgpk_data *priv = psmouse->private;
+
+	if (hgpk_validate_byte(psmouse->packet)) {
+		hgpk_dbg(psmouse, "%s: (%d) %02x %02x %02x\n",
+				__func__, psmouse->pktcnt, psmouse->packet[0],
+				psmouse->packet[1], psmouse->packet[2]);
+		return PSMOUSE_BAD_DATA;
+	}
+
+	if (psmouse->pktcnt >= psmouse->pktsize) {
+		hgpk_process_packet(psmouse);
+		return PSMOUSE_FULL_PACKET;
+	}
+
+	if (priv->recalib_window) {
+		if (time_before(jiffies, priv->recalib_window)) {
+			/*
+			 * ugh, got a packet inside our recalibration
+			 * window, schedule another recalibration.
+			 */
+			hgpk_dbg(psmouse,
+				 "packet inside calibration window, "
+				 "queueing another recalibration\n");
+			psmouse_queue_work(psmouse, &priv->recalib_wq,
+					msecs_to_jiffies(1000));
+		}
+		priv->recalib_window = 0;
+	}
+
+	return PSMOUSE_GOOD_DATA;
+}
+
+static int hgpk_force_recalibrate(struct psmouse *psmouse)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+	struct hgpk_data *priv = psmouse->private;
+
+	/* C-series touchpads added the recalibrate command */
+	if (psmouse->model < HGPK_MODEL_C)
+		return 0;
+
+	/* we don't want to race with the irq handler, nor with resyncs */
+	psmouse_set_state(psmouse, PSMOUSE_INITIALIZING);
+
+	/* start by resetting the device */
+	psmouse_reset(psmouse);
+
+	/* send the recalibrate request */
+	if (ps2_command(ps2dev, NULL, 0xf5) ||
+	    ps2_command(ps2dev, NULL, 0xf5) ||
+	    ps2_command(ps2dev, NULL, 0xe6) ||
+	    ps2_command(ps2dev, NULL, 0xf5)) {
+		return -1;
+	}
+
+	/* according to ALPS, 150mS is required for recalibration */
+	msleep(150);
+
+	/* XXX: If a finger is down during this delay, recalibration will
+	 * detect capacitance incorrectly.  This is a hardware bug, and
+	 * we don't have a good way to deal with it.  The 2s window stuff
+	 * (below) is our best option for now.
+	 */
+
+	if (ps2_command(ps2dev, NULL, PSMOUSE_CMD_ENABLE))
+		return -1;
+
+	psmouse_set_state(psmouse, PSMOUSE_ACTIVATED);
+
+	/* After we recalibrate, we shouldn't get any packets for 2s.  If
+	 * we do, it's likely that someone's finger was on the touchpad.
+	 * If someone's finger *was* on the touchpad, it's probably
+	 * miscalibrated.  So, we should schedule another recalibration
+	 */
+	priv->recalib_window = jiffies +  msecs_to_jiffies(2000);
+
+	return 0;
+}
+
+/*
+ * This kills power to the touchpad; according to ALPS, current consumption
+ * goes down to 50uA after running this.  To turn power back on, we drive
+ * MS-DAT low.
+ */
+static int hgpk_toggle_power(struct psmouse *psmouse, int enable)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+	int timeo;
+
+	/* Added on D-series touchpads */
+	if (psmouse->model < HGPK_MODEL_D)
+		return 0;
+
+	if (enable) {
+		psmouse_set_state(psmouse, PSMOUSE_INITIALIZING);
+
+		/*
+		 * Sending a byte will drive MS-DAT low; this will wake up
+		 * the controller.  Once we get an ACK back from it, it
+		 * means we can continue with the touchpad re-init.  ALPS
+		 * tells us that 1s should be long enough, so set that as
+		 * the upper bound.
+		 */
+		for (timeo = 20; timeo > 0; timeo--) {
+			if (!ps2_sendbyte(&psmouse->ps2dev,
+					PSMOUSE_CMD_DISABLE, 20))
+				break;
+			msleep(50);
+		}
+
+		psmouse_reset(psmouse);
+
+		/* should be all set, enable the touchpad */
+		ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_ENABLE);
+		psmouse_set_state(psmouse, PSMOUSE_ACTIVATED);
+
+	} else {
+		hgpk_dbg(psmouse, "Powering off touchpad.\n");
+		psmouse_set_state(psmouse, PSMOUSE_IGNORE);
+
+		if (ps2_command(ps2dev, NULL, 0xec) ||
+		    ps2_command(ps2dev, NULL, 0xec) ||
+		    ps2_command(ps2dev, NULL, 0xea)) {
+			return -1;
+		}
+
+		/* probably won't see an ACK, the touchpad will be off */
+		ps2_sendbyte(&psmouse->ps2dev, 0xec, 20);
+	}
+
+	return 0;
+}
+
+static int hgpk_poll(struct psmouse *psmouse)
+{
+	/* We can't poll, so always return failure. */
+	return -1;
+}
+
+static int hgpk_reconnect(struct psmouse *psmouse)
+{
+	/* During suspend/resume the ps2 rails remain powered.  We don't want
+	 * to do a reset because it's flush data out of buffers; however,
+	 * earlier prototypes (B1) had some brokenness that required a reset. */
+	if (olpc_board_at_least(olpc_board(0xb2)))
+		if (psmouse->ps2dev.serio->dev.power.power_state.event !=
+				PM_EVENT_ON)
+			return 0;
+
+	psmouse_reset(psmouse);
+
+	return 0;
+}
+
+static ssize_t hgpk_show_powered(struct psmouse *psmouse, void *data, char *buf)
+{
+	struct hgpk_data *priv = psmouse->private;
+
+	return sprintf(buf, "%d\n", priv->powered);
+}
+
+static ssize_t hgpk_set_powered(struct psmouse *psmouse, void *data,
+				const char *buf, size_t count)
+{
+	struct hgpk_data *priv = psmouse->private;
+	unsigned long value;
+	int err;
+
+	err = strict_strtoul(buf, 10, &value);
+	if (err || value > 1)
+		return -EINVAL;
+
+	if (value != priv->powered) {
+		/*
+		 * hgpk_toggle_power will deal w/ state so
+		 * we're not racing w/ irq
+		 */
+		err = hgpk_toggle_power(psmouse, value);
+		if (!err)
+			priv->powered = value;
+	}
+
+	return err ? err : count;
+}
+
+__PSMOUSE_DEFINE_ATTR(powered, S_IWUSR | S_IRUGO, NULL,
+		      hgpk_show_powered, hgpk_set_powered, 0);
+
+static void hgpk_disconnect(struct psmouse *psmouse)
+{
+	struct hgpk_data *priv = psmouse->private;
+
+	device_remove_file(&psmouse->ps2dev.serio->dev,
+			   &psmouse_attr_powered.dattr);
+	psmouse_reset(psmouse);
+	kfree(priv);
+}
+
+static void hgpk_recalib_work(struct work_struct *work)
+{
+	struct delayed_work *w = container_of(work, struct delayed_work, work);
+	struct hgpk_data *priv = container_of(w, struct hgpk_data, recalib_wq);
+	struct psmouse *psmouse = priv->psmouse;
+
+	hgpk_dbg(psmouse, "recalibrating touchpad..\n");
+
+	if (hgpk_force_recalibrate(psmouse))
+		hgpk_err(psmouse, "recalibration failed!\n");
+}
+
+static int hgpk_register(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	int err;
+
+	/* unset the things that psmouse-base sets which we don't have */
+	__clear_bit(BTN_MIDDLE, dev->keybit);
+
+	/* set the things we do have */
+	__set_bit(EV_KEY, dev->evbit);
+	__set_bit(EV_REL, dev->evbit);
+
+	__set_bit(REL_X, dev->relbit);
+	__set_bit(REL_Y, dev->relbit);
+
+	__set_bit(BTN_LEFT, dev->keybit);
+	__set_bit(BTN_RIGHT, dev->keybit);
+
+	/* register handlers */
+	psmouse->protocol_handler = hgpk_process_byte;
+	psmouse->poll = hgpk_poll;
+	psmouse->disconnect = hgpk_disconnect;
+	psmouse->reconnect = hgpk_reconnect;
+	psmouse->pktsize = 3;
+
+	/* Disable the idle resync. */
+	psmouse->resync_time = 0;
+	/* Reset after a lot of bad bytes. */
+	psmouse->resetafter = 1024;
+
+	err = device_create_file(&psmouse->ps2dev.serio->dev,
+				 &psmouse_attr_powered.dattr);
+	if (err)
+		hgpk_err(psmouse, "Failed to create sysfs attribute\n");
+
+	return err;
+}
+
+int hgpk_init(struct psmouse *psmouse)
+{
+	struct hgpk_data *priv;
+	int err = -ENOMEM;
+
+	priv = kzalloc(sizeof(struct hgpk_data), GFP_KERNEL);
+	if (!priv)
+		goto alloc_fail;
+
+	psmouse->private = priv;
+	priv->psmouse = psmouse;
+	priv->powered = 1;
+	INIT_DELAYED_WORK(&priv->recalib_wq, hgpk_recalib_work);
+
+	err = psmouse_reset(psmouse);
+	if (err)
+		goto init_fail;
+
+	err = hgpk_register(psmouse);
+	if (err)
+		goto init_fail;
+
+	return 0;
+
+init_fail:
+	kfree(priv);
+alloc_fail:
+	return err;
+}
+
+static enum hgpk_model_t hgpk_get_model(struct psmouse *psmouse)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+	unsigned char param[3];
+
+	/* E7, E7, E7, E9 gets us a 3 byte identifier */
+	if (ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE21) ||
+	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE21) ||
+	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE21) ||
+	    ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
+		return -EIO;
+	}
+
+	hgpk_dbg(psmouse, "ID: %02x %02x %02x", param[0], param[1], param[2]);
+
+	/* HGPK signature: 0x67, 0x00, 0x<model> */
+	if (param[0] != 0x67 || param[1] != 0x00)
+		return -ENODEV;
+
+	hgpk_info(psmouse, "OLPC touchpad revision 0x%x\n", param[2]);
+
+	return param[2];
+}
+
+int hgpk_detect(struct psmouse *psmouse, int set_properties)
+{
+	int version;
+
+	version = hgpk_get_model(psmouse);
+	if (version < 0)
+		return version;
+
+	if (set_properties) {
+		psmouse->vendor = "ALPS";
+		psmouse->name = "HGPK";
+		psmouse->model = version;
+	}
+
+	return 0;
+}