Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 2224 insertions, 0 deletions

diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
new file mode 100644
index 000000000..f8575b80d
--- /dev/null
+++ b/drivers/input/mouse/elantech.c
@@ -0,0 +1,2224 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Elantech Touchpad driver (v6)
+ *
+ * Copyright (C) 2007-2009 Arjan Opmeer <arjan@opmeer.net>
+ *
+ * Trademarks are the property of their respective owners.
+ */
+
+#include <linux/delay.h>
+#include <linux/dmi.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/platform_device.h>
+#include <linux/serio.h>
+#include <linux/libps2.h>
+#include <linux/unaligned.h>
+#include "psmouse.h"
+#include "elantech.h"
+#include "elan_i2c.h"
+
+#define elantech_debug(fmt, ...)					\
+	do {								\
+		if (etd->info.debug)					\
+			psmouse_printk(KERN_DEBUG, psmouse,		\
+					fmt, ##__VA_ARGS__);		\
+	} while (0)
+
+/*
+ * Send a Synaptics style sliced query command
+ */
+static int synaptics_send_cmd(struct psmouse *psmouse, unsigned char c,
+				unsigned char *param)
+{
+	if (ps2_sliced_command(&psmouse->ps2dev, c) ||
+	    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
+		psmouse_err(psmouse, "%s query 0x%02x failed.\n", __func__, c);
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * V3 and later support this fast command
+ */
+static int elantech_send_cmd(struct psmouse *psmouse, unsigned char c,
+				unsigned char *param)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+
+	if (ps2_command(ps2dev, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+	    ps2_command(ps2dev, NULL, c) ||
+	    ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
+		psmouse_err(psmouse, "%s query 0x%02x failed.\n", __func__, c);
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * A retrying version of ps2_command
+ */
+static int elantech_ps2_command(struct psmouse *psmouse,
+				unsigned char *param, int command)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+	struct elantech_data *etd = psmouse->private;
+	int rc;
+	int tries = ETP_PS2_COMMAND_TRIES;
+
+	do {
+		rc = ps2_command(ps2dev, param, command);
+		if (rc == 0)
+			break;
+		tries--;
+		elantech_debug("retrying ps2 command 0x%02x (%d).\n",
+				command, tries);
+		msleep(ETP_PS2_COMMAND_DELAY);
+	} while (tries > 0);
+
+	if (rc)
+		psmouse_err(psmouse, "ps2 command 0x%02x failed.\n", command);
+
+	return rc;
+}
+
+/*
+ * Send an Elantech style special command to read 3 bytes from a register
+ */
+static int elantech_read_reg_params(struct psmouse *psmouse, u8 reg, u8 *param)
+{
+	if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+	    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
+	    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+	    elantech_ps2_command(psmouse, NULL, reg) ||
+	    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
+		psmouse_err(psmouse,
+			    "failed to read register %#02x\n", reg);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * Send an Elantech style special command to write a register with a parameter
+ */
+static int elantech_write_reg_params(struct psmouse *psmouse, u8 reg, u8 *param)
+{
+	if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+	    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
+	    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+	    elantech_ps2_command(psmouse, NULL, reg) ||
+	    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+	    elantech_ps2_command(psmouse, NULL, param[0]) ||
+	    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+	    elantech_ps2_command(psmouse, NULL, param[1]) ||
+	    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
+		psmouse_err(psmouse,
+			    "failed to write register %#02x with value %#02x%#02x\n",
+			    reg, param[0], param[1]);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * Send an Elantech style special command to read a value from a register
+ */
+static int elantech_read_reg(struct psmouse *psmouse, unsigned char reg,
+				unsigned char *val)
+{
+	struct elantech_data *etd = psmouse->private;
+	unsigned char param[3];
+	int rc = 0;
+
+	if (reg < 0x07 || reg > 0x26)
+		return -1;
+
+	if (reg > 0x11 && reg < 0x20)
+		return -1;
+
+	switch (etd->info.hw_version) {
+	case 1:
+		if (ps2_sliced_command(&psmouse->ps2dev, ETP_REGISTER_READ) ||
+		    ps2_sliced_command(&psmouse->ps2dev, reg) ||
+		    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
+			rc = -1;
+		}
+		break;
+
+	case 2:
+		if (elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse,  NULL, ETP_REGISTER_READ) ||
+		    elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse,  NULL, reg) ||
+		    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
+			rc = -1;
+		}
+		break;
+
+	case 3 ... 4:
+		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
+		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse, NULL, reg) ||
+		    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
+			rc = -1;
+		}
+		break;
+	}
+
+	if (rc)
+		psmouse_err(psmouse, "failed to read register 0x%02x.\n", reg);
+	else if (etd->info.hw_version != 4)
+		*val = param[0];
+	else
+		*val = param[1];
+
+	return rc;
+}
+
+/*
+ * Send an Elantech style special command to write a register with a value
+ */
+static int elantech_write_reg(struct psmouse *psmouse, unsigned char reg,
+				unsigned char val)
+{
+	struct elantech_data *etd = psmouse->private;
+	int rc = 0;
+
+	if (reg < 0x07 || reg > 0x26)
+		return -1;
+
+	if (reg > 0x11 && reg < 0x20)
+		return -1;
+
+	switch (etd->info.hw_version) {
+	case 1:
+		if (ps2_sliced_command(&psmouse->ps2dev, ETP_REGISTER_WRITE) ||
+		    ps2_sliced_command(&psmouse->ps2dev, reg) ||
+		    ps2_sliced_command(&psmouse->ps2dev, val) ||
+		    ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_SETSCALE11)) {
+			rc = -1;
+		}
+		break;
+
+	case 2:
+		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_WRITE) ||
+		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse, NULL, reg) ||
+		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse, NULL, val) ||
+		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
+			rc = -1;
+		}
+		break;
+
+	case 3:
+		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
+		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse, NULL, reg) ||
+		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse, NULL, val) ||
+		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
+			rc = -1;
+		}
+		break;
+
+	case 4:
+		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
+		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse, NULL, reg) ||
+		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
+		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+		    elantech_ps2_command(psmouse, NULL, val) ||
+		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
+			rc = -1;
+		}
+		break;
+	}
+
+	if (rc)
+		psmouse_err(psmouse,
+			    "failed to write register 0x%02x with value 0x%02x.\n",
+			    reg, val);
+
+	return rc;
+}
+
+/*
+ * Dump a complete mouse movement packet to the syslog
+ */
+static void elantech_packet_dump(struct psmouse *psmouse)
+{
+	psmouse_printk(KERN_DEBUG, psmouse, "PS/2 packet [%*ph]\n",
+		       psmouse->pktsize, psmouse->packet);
+}
+
+/*
+ * Advertise INPUT_PROP_BUTTONPAD for clickpads. The testing of bit 12 in
+ * fw_version for this is based on the following fw_version & caps table:
+ *
+ * Laptop-model:           fw_version:     caps:           buttons:
+ * Acer S3                 0x461f00        10, 13, 0e      clickpad
+ * Acer S7-392             0x581f01        50, 17, 0d      clickpad
+ * Acer V5-131             0x461f02        01, 16, 0c      clickpad
+ * Acer V5-551             0x461f00        ?               clickpad
+ * Asus K53SV              0x450f01        78, 15, 0c      2 hw buttons
+ * Asus G46VW              0x460f02        00, 18, 0c      2 hw buttons
+ * Asus G750JX             0x360f00        00, 16, 0c      2 hw buttons
+ * Asus TP500LN            0x381f17        10, 14, 0e      clickpad
+ * Asus X750JN             0x381f17        10, 14, 0e      clickpad
+ * Asus UX31               0x361f00        20, 15, 0e      clickpad
+ * Asus UX32VD             0x361f02        00, 15, 0e      clickpad
+ * Avatar AVIU-145A2       0x361f00        ?               clickpad
+ * Fujitsu CELSIUS H760    0x570f02        40, 14, 0c      3 hw buttons (**)
+ * Fujitsu CELSIUS H780    0x5d0f02        41, 16, 0d      3 hw buttons (**)
+ * Fujitsu LIFEBOOK E544   0x470f00        d0, 12, 09      2 hw buttons
+ * Fujitsu LIFEBOOK E546   0x470f00        50, 12, 09      2 hw buttons
+ * Fujitsu LIFEBOOK E547   0x470f00        50, 12, 09      2 hw buttons
+ * Fujitsu LIFEBOOK E554   0x570f01        40, 14, 0c      2 hw buttons
+ * Fujitsu LIFEBOOK E557   0x570f01        40, 14, 0c      2 hw buttons
+ * Fujitsu T725            0x470f01        05, 12, 09      2 hw buttons
+ * Fujitsu H730            0x570f00        c0, 14, 0c      3 hw buttons (**)
+ * Gigabyte U2442          0x450f01        58, 17, 0c      2 hw buttons
+ * Lenovo L430             0x350f02        b9, 15, 0c      2 hw buttons (*)
+ * Lenovo L530             0x350f02        b9, 15, 0c      2 hw buttons (*)
+ * Samsung NF210           0x150b00        78, 14, 0a      2 hw buttons
+ * Samsung NP770Z5E        0x575f01        10, 15, 0f      clickpad
+ * Samsung NP700Z5B        0x361f06        21, 15, 0f      clickpad
+ * Samsung NP900X3E-A02    0x575f03        ?               clickpad
+ * Samsung NP-QX410        0x851b00        19, 14, 0c      clickpad
+ * Samsung RC512           0x450f00        08, 15, 0c      2 hw buttons
+ * Samsung RF710           0x450f00        ?               2 hw buttons
+ * System76 Pangolin       0x250f01        ?               2 hw buttons
+ * (*) + 3 trackpoint buttons
+ * (**) + 0 trackpoint buttons
+ * Note: Lenovo L430 and Lenovo L530 have the same fw_version/caps
+ */
+static inline int elantech_is_buttonpad(struct elantech_device_info *info)
+{
+	return info->fw_version & 0x001000;
+}
+
+/*
+ * Interpret complete data packets and report absolute mode input events for
+ * hardware version 1. (4 byte packets)
+ */
+static void elantech_report_absolute_v1(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	struct elantech_data *etd = psmouse->private;
+	unsigned char *packet = psmouse->packet;
+	int fingers;
+
+	if (etd->info.fw_version < 0x020000) {
+		/*
+		 * byte 0:  D   U  p1  p2   1  p3   R   L
+		 * byte 1:  f   0  th  tw  x9  x8  y9  y8
+		 */
+		fingers = ((packet[1] & 0x80) >> 7) +
+				((packet[1] & 0x30) >> 4);
+	} else {
+		/*
+		 * byte 0: n1  n0  p2  p1   1  p3   R   L
+		 * byte 1:  0   0   0   0  x9  x8  y9  y8
+		 */
+		fingers = (packet[0] & 0xc0) >> 6;
+	}
+
+	if (etd->info.jumpy_cursor) {
+		if (fingers != 1) {
+			etd->single_finger_reports = 0;
+		} else if (etd->single_finger_reports < 2) {
+			/* Discard first 2 reports of one finger, bogus */
+			etd->single_finger_reports++;
+			elantech_debug("discarding packet\n");
+			return;
+		}
+	}
+
+	input_report_key(dev, BTN_TOUCH, fingers != 0);
+
+	/*
+	 * byte 2: x7  x6  x5  x4  x3  x2  x1  x0
+	 * byte 3: y7  y6  y5  y4  y3  y2  y1  y0
+	 */
+	if (fingers) {
+		input_report_abs(dev, ABS_X,
+			((packet[1] & 0x0c) << 6) | packet[2]);
+		input_report_abs(dev, ABS_Y,
+			etd->y_max - (((packet[1] & 0x03) << 8) | packet[3]));
+	}
+
+	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
+	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
+	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
+
+	psmouse_report_standard_buttons(dev, packet[0]);
+
+	if (etd->info.fw_version < 0x020000 &&
+	    (etd->info.capabilities[0] & ETP_CAP_HAS_ROCKER)) {
+		/* rocker up */
+		input_report_key(dev, BTN_FORWARD, packet[0] & 0x40);
+		/* rocker down */
+		input_report_key(dev, BTN_BACK, packet[0] & 0x80);
+	}
+
+	input_sync(dev);
+}
+
+static void elantech_set_slot(struct input_dev *dev, int slot, bool active,
+			      unsigned int x, unsigned int y)
+{
+	input_mt_slot(dev, slot);
+	input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
+	if (active) {
+		input_report_abs(dev, ABS_MT_POSITION_X, x);
+		input_report_abs(dev, ABS_MT_POSITION_Y, y);
+	}
+}
+
+/* x1 < x2 and y1 < y2 when two fingers, x = y = 0 when not pressed */
+static void elantech_report_semi_mt_data(struct input_dev *dev,
+					 unsigned int num_fingers,
+					 unsigned int x1, unsigned int y1,
+					 unsigned int x2, unsigned int y2)
+{
+	elantech_set_slot(dev, 0, num_fingers != 0, x1, y1);
+	elantech_set_slot(dev, 1, num_fingers >= 2, x2, y2);
+}
+
+/*
+ * Interpret complete data packets and report absolute mode input events for
+ * hardware version 2. (6 byte packets)
+ */
+static void elantech_report_absolute_v2(struct psmouse *psmouse)
+{
+	struct elantech_data *etd = psmouse->private;
+	struct input_dev *dev = psmouse->dev;
+	unsigned char *packet = psmouse->packet;
+	unsigned int fingers, x1 = 0, y1 = 0, x2 = 0, y2 = 0;
+	unsigned int width = 0, pres = 0;
+
+	/* byte 0: n1  n0   .   .   .   .   R   L */
+	fingers = (packet[0] & 0xc0) >> 6;
+
+	switch (fingers) {
+	case 3:
+		/*
+		 * Same as one finger, except report of more than 3 fingers:
+		 * byte 3:  n4  .   w1  w0   .   .   .   .
+		 */
+		if (packet[3] & 0x80)
+			fingers = 4;
+		fallthrough;
+	case 1:
+		/*
+		 * byte 1:  .   .   .   .  x11 x10 x9  x8
+		 * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
+		 */
+		x1 = ((packet[1] & 0x0f) << 8) | packet[2];
+		/*
+		 * byte 4:  .   .   .   .  y11 y10 y9  y8
+		 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
+		 */
+		y1 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
+
+		pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
+		width = ((packet[0] & 0x30) >> 2) | ((packet[3] & 0x30) >> 4);
+		break;
+
+	case 2:
+		/*
+		 * The coordinate of each finger is reported separately
+		 * with a lower resolution for two finger touches:
+		 * byte 0:  .   .  ay8 ax8  .   .   .   .
+		 * byte 1: ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0
+		 */
+		x1 = (((packet[0] & 0x10) << 4) | packet[1]) << 2;
+		/* byte 2: ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0 */
+		y1 = etd->y_max -
+			((((packet[0] & 0x20) << 3) | packet[2]) << 2);
+		/*
+		 * byte 3:  .   .  by8 bx8  .   .   .   .
+		 * byte 4: bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0
+		 */
+		x2 = (((packet[3] & 0x10) << 4) | packet[4]) << 2;
+		/* byte 5: by7 by8 by5 by4 by3 by2 by1 by0 */
+		y2 = etd->y_max -
+			((((packet[3] & 0x20) << 3) | packet[5]) << 2);
+
+		/* Unknown so just report sensible values */
+		pres = 127;
+		width = 7;
+		break;
+	}
+
+	input_report_key(dev, BTN_TOUCH, fingers != 0);
+	if (fingers != 0) {
+		input_report_abs(dev, ABS_X, x1);
+		input_report_abs(dev, ABS_Y, y1);
+	}
+	elantech_report_semi_mt_data(dev, fingers, x1, y1, x2, y2);
+	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
+	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
+	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
+	input_report_key(dev, BTN_TOOL_QUADTAP, fingers == 4);
+	psmouse_report_standard_buttons(dev, packet[0]);
+	if (etd->info.reports_pressure) {
+		input_report_abs(dev, ABS_PRESSURE, pres);
+		input_report_abs(dev, ABS_TOOL_WIDTH, width);
+	}
+
+	input_sync(dev);
+}
+
+static void elantech_report_trackpoint(struct psmouse *psmouse,
+				       int packet_type)
+{
+	/*
+	 * byte 0:  0   0  sx  sy   0   M   R   L
+	 * byte 1:~sx   0   0   0   0   0   0   0
+	 * byte 2:~sy   0   0   0   0   0   0   0
+	 * byte 3:  0   0 ~sy ~sx   0   1   1   0
+	 * byte 4: x7  x6  x5  x4  x3  x2  x1  x0
+	 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
+	 *
+	 * x and y are written in two's complement spread
+	 * over 9 bits with sx/sy the relative top bit and
+	 * x7..x0 and y7..y0 the lower bits.
+	 * The sign of y is opposite to what the input driver
+	 * expects for a relative movement
+	 */
+
+	struct elantech_data *etd = psmouse->private;
+	struct input_dev *tp_dev = etd->tp_dev;
+	unsigned char *packet = psmouse->packet;
+	int x, y;
+	u32 t;
+
+	t = get_unaligned_le32(&packet[0]);
+
+	switch (t & ~7U) {
+	case 0x06000030U:
+	case 0x16008020U:
+	case 0x26800010U:
+	case 0x36808000U:
+
+		/*
+		 * This firmware misreport coordinates for trackpoint
+		 * occasionally. Discard packets outside of [-127, 127] range
+		 * to prevent cursor jumps.
+		 */
+		if (packet[4] == 0x80 || packet[5] == 0x80 ||
+		    packet[1] >> 7 == packet[4] >> 7 ||
+		    packet[2] >> 7 == packet[5] >> 7) {
+			elantech_debug("discarding packet [%6ph]\n", packet);
+			break;
+
+		}
+		x = packet[4] - (int)((packet[1]^0x80) << 1);
+		y = (int)((packet[2]^0x80) << 1) - packet[5];
+
+		psmouse_report_standard_buttons(tp_dev, packet[0]);
+
+		input_report_rel(tp_dev, REL_X, x);
+		input_report_rel(tp_dev, REL_Y, y);
+
+		input_sync(tp_dev);
+
+		break;
+
+	default:
+		/* Dump unexpected packet sequences if debug=1 (default) */
+		if (etd->info.debug == 1)
+			elantech_packet_dump(psmouse);
+
+		break;
+	}
+}
+
+/*
+ * Interpret complete data packets and report absolute mode input events for
+ * hardware version 3. (12 byte packets for two fingers)
+ */
+static void elantech_report_absolute_v3(struct psmouse *psmouse,
+					int packet_type)
+{
+	struct input_dev *dev = psmouse->dev;
+	struct elantech_data *etd = psmouse->private;
+	unsigned char *packet = psmouse->packet;
+	unsigned int fingers = 0, x1 = 0, y1 = 0, x2 = 0, y2 = 0;
+	unsigned int width = 0, pres = 0;
+
+	/* byte 0: n1  n0   .   .   .   .   R   L */
+	fingers = (packet[0] & 0xc0) >> 6;
+
+	switch (fingers) {
+	case 3:
+	case 1:
+		/*
+		 * byte 1:  .   .   .   .  x11 x10 x9  x8
+		 * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
+		 */
+		x1 = ((packet[1] & 0x0f) << 8) | packet[2];
+		/*
+		 * byte 4:  .   .   .   .  y11 y10 y9  y8
+		 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
+		 */
+		y1 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
+		break;
+
+	case 2:
+		if (packet_type == PACKET_V3_HEAD) {
+			/*
+			 * byte 1:   .    .    .    .  ax11 ax10 ax9  ax8
+			 * byte 2: ax7  ax6  ax5  ax4  ax3  ax2  ax1  ax0
+			 */
+			etd->mt[0].x = ((packet[1] & 0x0f) << 8) | packet[2];
+			/*
+			 * byte 4:   .    .    .    .  ay11 ay10 ay9  ay8
+			 * byte 5: ay7  ay6  ay5  ay4  ay3  ay2  ay1  ay0
+			 */
+			etd->mt[0].y = etd->y_max -
+				(((packet[4] & 0x0f) << 8) | packet[5]);
+			/*
+			 * wait for next packet
+			 */
+			return;
+		}
+
+		/* packet_type == PACKET_V3_TAIL */
+		x1 = etd->mt[0].x;
+		y1 = etd->mt[0].y;
+		x2 = ((packet[1] & 0x0f) << 8) | packet[2];
+		y2 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
+		break;
+	}
+
+	pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
+	width = ((packet[0] & 0x30) >> 2) | ((packet[3] & 0x30) >> 4);
+
+	input_report_key(dev, BTN_TOUCH, fingers != 0);
+	if (fingers != 0) {
+		input_report_abs(dev, ABS_X, x1);
+		input_report_abs(dev, ABS_Y, y1);
+	}
+	elantech_report_semi_mt_data(dev, fingers, x1, y1, x2, y2);
+	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
+	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
+	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
+
+	/* For clickpads map both buttons to BTN_LEFT */
+	if (elantech_is_buttonpad(&etd->info))
+		input_report_key(dev, BTN_LEFT, packet[0] & 0x03);
+	else
+		psmouse_report_standard_buttons(dev, packet[0]);
+
+	input_report_abs(dev, ABS_PRESSURE, pres);
+	input_report_abs(dev, ABS_TOOL_WIDTH, width);
+
+	input_sync(dev);
+}
+
+static void elantech_input_sync_v4(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	struct elantech_data *etd = psmouse->private;
+	unsigned char *packet = psmouse->packet;
+
+	/* For clickpads map both buttons to BTN_LEFT */
+	if (elantech_is_buttonpad(&etd->info))
+		input_report_key(dev, BTN_LEFT, packet[0] & 0x03);
+	else
+		psmouse_report_standard_buttons(dev, packet[0]);
+
+	input_mt_report_pointer_emulation(dev, true);
+	input_sync(dev);
+}
+
+static void process_packet_status_v4(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	unsigned char *packet = psmouse->packet;
+	unsigned fingers;
+	int i;
+
+	/* notify finger state change */
+	fingers = packet[1] & 0x1f;
+	for (i = 0; i < ETP_MAX_FINGERS; i++) {
+		if ((fingers & (1 << i)) == 0) {
+			input_mt_slot(dev, i);
+			input_mt_report_slot_state(dev, MT_TOOL_FINGER, false);
+		}
+	}
+
+	elantech_input_sync_v4(psmouse);
+}
+
+static void process_packet_head_v4(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	struct elantech_data *etd = psmouse->private;
+	unsigned char *packet = psmouse->packet;
+	int id;
+	int pres, traces;
+
+	id = ((packet[3] & 0xe0) >> 5) - 1;
+	if (id < 0 || id >= ETP_MAX_FINGERS)
+		return;
+
+	etd->mt[id].x = ((packet[1] & 0x0f) << 8) | packet[2];
+	etd->mt[id].y = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
+	pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
+	traces = (packet[0] & 0xf0) >> 4;
+
+	input_mt_slot(dev, id);
+	input_mt_report_slot_state(dev, MT_TOOL_FINGER, true);
+
+	input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[id].x);
+	input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[id].y);
+	input_report_abs(dev, ABS_MT_PRESSURE, pres);
+	input_report_abs(dev, ABS_MT_TOUCH_MAJOR, traces * etd->width);
+	/* report this for backwards compatibility */
+	input_report_abs(dev, ABS_TOOL_WIDTH, traces);
+
+	elantech_input_sync_v4(psmouse);
+}
+
+static void process_packet_motion_v4(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	struct elantech_data *etd = psmouse->private;
+	unsigned char *packet = psmouse->packet;
+	int weight, delta_x1 = 0, delta_y1 = 0, delta_x2 = 0, delta_y2 = 0;
+	int id, sid;
+
+	id = ((packet[0] & 0xe0) >> 5) - 1;
+	if (id < 0 || id >= ETP_MAX_FINGERS)
+		return;
+
+	sid = ((packet[3] & 0xe0) >> 5) - 1;
+	weight = (packet[0] & 0x10) ? ETP_WEIGHT_VALUE : 1;
+	/*
+	 * Motion packets give us the delta of x, y values of specific fingers,
+	 * but in two's complement. Let the compiler do the conversion for us.
+	 * Also _enlarge_ the numbers to int, in case of overflow.
+	 */
+	delta_x1 = (signed char)packet[1];
+	delta_y1 = (signed char)packet[2];
+	delta_x2 = (signed char)packet[4];
+	delta_y2 = (signed char)packet[5];
+
+	etd->mt[id].x += delta_x1 * weight;
+	etd->mt[id].y -= delta_y1 * weight;
+	input_mt_slot(dev, id);
+	input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[id].x);
+	input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[id].y);
+
+	if (sid >= 0 && sid < ETP_MAX_FINGERS) {
+		etd->mt[sid].x += delta_x2 * weight;
+		etd->mt[sid].y -= delta_y2 * weight;
+		input_mt_slot(dev, sid);
+		input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[sid].x);
+		input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[sid].y);
+	}
+
+	elantech_input_sync_v4(psmouse);
+}
+
+static void elantech_report_absolute_v4(struct psmouse *psmouse,
+					int packet_type)
+{
+	switch (packet_type) {
+	case PACKET_V4_STATUS:
+		process_packet_status_v4(psmouse);
+		break;
+
+	case PACKET_V4_HEAD:
+		process_packet_head_v4(psmouse);
+		break;
+
+	case PACKET_V4_MOTION:
+		process_packet_motion_v4(psmouse);
+		break;
+
+	case PACKET_UNKNOWN:
+	default:
+		/* impossible to get here */
+		break;
+	}
+}
+
+static int elantech_packet_check_v1(struct psmouse *psmouse)
+{
+	struct elantech_data *etd = psmouse->private;
+	unsigned char *packet = psmouse->packet;
+	unsigned char p1, p2, p3;
+
+	/* Parity bits are placed differently */
+	if (etd->info.fw_version < 0x020000) {
+		/* byte 0:  D   U  p1  p2   1  p3   R   L */
+		p1 = (packet[0] & 0x20) >> 5;
+		p2 = (packet[0] & 0x10) >> 4;
+	} else {
+		/* byte 0: n1  n0  p2  p1   1  p3   R   L */
+		p1 = (packet[0] & 0x10) >> 4;
+		p2 = (packet[0] & 0x20) >> 5;
+	}
+
+	p3 = (packet[0] & 0x04) >> 2;
+
+	return etd->parity[packet[1]] == p1 &&
+	       etd->parity[packet[2]] == p2 &&
+	       etd->parity[packet[3]] == p3;
+}
+
+static int elantech_debounce_check_v2(struct psmouse *psmouse)
+{
+        /*
+         * When we encounter packet that matches this exactly, it means the
+         * hardware is in debounce status. Just ignore the whole packet.
+         */
+	static const u8 debounce_packet[] = {
+		0x84, 0xff, 0xff, 0x02, 0xff, 0xff
+	};
+        unsigned char *packet = psmouse->packet;
+
+        return !memcmp(packet, debounce_packet, sizeof(debounce_packet));
+}
+
+static int elantech_packet_check_v2(struct psmouse *psmouse)
+{
+	struct elantech_data *etd = psmouse->private;
+	unsigned char *packet = psmouse->packet;
+
+	/*
+	 * V2 hardware has two flavors. Older ones that do not report pressure,
+	 * and newer ones that reports pressure and width. With newer ones, all
+	 * packets (1, 2, 3 finger touch) have the same constant bits. With
+	 * older ones, 1/3 finger touch packets and 2 finger touch packets
+	 * have different constant bits.
+	 * With all three cases, if the constant bits are not exactly what I
+	 * expected, I consider them invalid.
+	 */
+	if (etd->info.reports_pressure)
+		return (packet[0] & 0x0c) == 0x04 &&
+		       (packet[3] & 0x0f) == 0x02;
+
+	if ((packet[0] & 0xc0) == 0x80)
+		return (packet[0] & 0x0c) == 0x0c &&
+		       (packet[3] & 0x0e) == 0x08;
+
+	return (packet[0] & 0x3c) == 0x3c &&
+	       (packet[1] & 0xf0) == 0x00 &&
+	       (packet[3] & 0x3e) == 0x38 &&
+	       (packet[4] & 0xf0) == 0x00;
+}
+
+/*
+ * We check the constant bits to determine what packet type we get,
+ * so packet checking is mandatory for v3 and later hardware.
+ */
+static int elantech_packet_check_v3(struct psmouse *psmouse)
+{
+	struct elantech_data *etd = psmouse->private;
+	static const u8 debounce_packet[] = {
+		0xc4, 0xff, 0xff, 0x02, 0xff, 0xff
+	};
+	unsigned char *packet = psmouse->packet;
+
+	/*
+	 * check debounce first, it has the same signature in byte 0
+	 * and byte 3 as PACKET_V3_HEAD.
+	 */
+	if (!memcmp(packet, debounce_packet, sizeof(debounce_packet)))
+		return PACKET_DEBOUNCE;
+
+	/*
+	 * If the hardware flag 'crc_enabled' is set the packets have
+	 * different signatures.
+	 */
+	if (etd->info.crc_enabled) {
+		if ((packet[3] & 0x09) == 0x08)
+			return PACKET_V3_HEAD;
+
+		if ((packet[3] & 0x09) == 0x09)
+			return PACKET_V3_TAIL;
+	} else {
+		if ((packet[0] & 0x0c) == 0x04 && (packet[3] & 0xcf) == 0x02)
+			return PACKET_V3_HEAD;
+
+		if ((packet[0] & 0x0c) == 0x0c && (packet[3] & 0xce) == 0x0c)
+			return PACKET_V3_TAIL;
+		if ((packet[3] & 0x0f) == 0x06)
+			return PACKET_TRACKPOINT;
+	}
+
+	return PACKET_UNKNOWN;
+}
+
+static int elantech_packet_check_v4(struct psmouse *psmouse)
+{
+	struct elantech_data *etd = psmouse->private;
+	unsigned char *packet = psmouse->packet;
+	unsigned char packet_type = packet[3] & 0x03;
+	unsigned int ic_version;
+	bool sanity_check;
+
+	if (etd->tp_dev && (packet[3] & 0x0f) == 0x06)
+		return PACKET_TRACKPOINT;
+
+	/* This represents the version of IC body. */
+	ic_version = (etd->info.fw_version & 0x0f0000) >> 16;
+
+	/*
+	 * Sanity check based on the constant bits of a packet.
+	 * The constant bits change depending on the value of
+	 * the hardware flag 'crc_enabled' and the version of
+	 * the IC body, but are the same for every packet,
+	 * regardless of the type.
+	 */
+	if (etd->info.crc_enabled)
+		sanity_check = ((packet[3] & 0x08) == 0x00);
+	else if (ic_version == 7 && etd->info.samples[1] == 0x2A)
+		sanity_check = ((packet[3] & 0x1c) == 0x10);
+	else
+		sanity_check = ((packet[0] & 0x08) == 0x00 &&
+				(packet[3] & 0x1c) == 0x10);
+
+	if (!sanity_check)
+		return PACKET_UNKNOWN;
+
+	switch (packet_type) {
+	case 0:
+		return PACKET_V4_STATUS;
+
+	case 1:
+		return PACKET_V4_HEAD;
+
+	case 2:
+		return PACKET_V4_MOTION;
+	}
+
+	return PACKET_UNKNOWN;
+}
+
+/*
+ * Process byte stream from mouse and handle complete packets
+ */
+static psmouse_ret_t elantech_process_byte(struct psmouse *psmouse)
+{
+	struct elantech_data *etd = psmouse->private;
+	int packet_type;
+
+	if (psmouse->pktcnt < psmouse->pktsize)
+		return PSMOUSE_GOOD_DATA;
+
+	if (etd->info.debug > 1)
+		elantech_packet_dump(psmouse);
+
+	switch (etd->info.hw_version) {
+	case 1:
+		if (etd->info.paritycheck && !elantech_packet_check_v1(psmouse))
+			return PSMOUSE_BAD_DATA;
+
+		elantech_report_absolute_v1(psmouse);
+		break;
+
+	case 2:
+		/* ignore debounce */
+		if (elantech_debounce_check_v2(psmouse))
+			return PSMOUSE_FULL_PACKET;
+
+		if (etd->info.paritycheck && !elantech_packet_check_v2(psmouse))
+			return PSMOUSE_BAD_DATA;
+
+		elantech_report_absolute_v2(psmouse);
+		break;
+
+	case 3:
+		packet_type = elantech_packet_check_v3(psmouse);
+		switch (packet_type) {
+		case PACKET_UNKNOWN:
+			return PSMOUSE_BAD_DATA;
+
+		case PACKET_DEBOUNCE:
+			/* ignore debounce */
+			break;
+
+		case PACKET_TRACKPOINT:
+			elantech_report_trackpoint(psmouse, packet_type);
+			break;
+
+		default:
+			elantech_report_absolute_v3(psmouse, packet_type);
+			break;
+		}
+
+		break;
+
+	case 4:
+		packet_type = elantech_packet_check_v4(psmouse);
+		switch (packet_type) {
+		case PACKET_UNKNOWN:
+			return PSMOUSE_BAD_DATA;
+
+		case PACKET_TRACKPOINT:
+			elantech_report_trackpoint(psmouse, packet_type);
+			break;
+
+		default:
+			elantech_report_absolute_v4(psmouse, packet_type);
+			break;
+		}
+
+		break;
+	}
+
+	return PSMOUSE_FULL_PACKET;
+}
+
+/*
+ * This writes the reg_07 value again to the hardware at the end of every
+ * set_rate call because the register loses its value. reg_07 allows setting
+ * absolute mode on v4 hardware
+ */
+static void elantech_set_rate_restore_reg_07(struct psmouse *psmouse,
+		unsigned int rate)
+{
+	struct elantech_data *etd = psmouse->private;
+
+	etd->original_set_rate(psmouse, rate);
+	if (elantech_write_reg(psmouse, 0x07, etd->reg_07))
+		psmouse_err(psmouse, "restoring reg_07 failed\n");
+}
+
+/*
+ * Put the touchpad into absolute mode
+ */
+static int elantech_set_absolute_mode(struct psmouse *psmouse)
+{
+	struct elantech_data *etd = psmouse->private;
+	unsigned char val;
+	int tries = ETP_READ_BACK_TRIES;
+	int rc = 0;
+
+	switch (etd->info.hw_version) {
+	case 1:
+		etd->reg_10 = 0x16;
+		etd->reg_11 = 0x8f;
+		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
+		    elantech_write_reg(psmouse, 0x11, etd->reg_11)) {
+			rc = -1;
+		}
+		break;
+
+	case 2:
+					/* Windows driver values */
+		etd->reg_10 = 0x54;
+		etd->reg_11 = 0x88;	/* 0x8a */
+		etd->reg_21 = 0x60;	/* 0x00 */
+		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
+		    elantech_write_reg(psmouse, 0x11, etd->reg_11) ||
+		    elantech_write_reg(psmouse, 0x21, etd->reg_21)) {
+			rc = -1;
+		}
+		break;
+
+	case 3:
+		if (etd->info.set_hw_resolution)
+			etd->reg_10 = 0x0b;
+		else
+			etd->reg_10 = 0x01;
+
+		if (elantech_write_reg(psmouse, 0x10, etd->reg_10))
+			rc = -1;
+
+		break;
+
+	case 4:
+		etd->reg_07 = 0x01;
+		if (elantech_write_reg(psmouse, 0x07, etd->reg_07))
+			rc = -1;
+
+		goto skip_readback_reg_10; /* v4 has no reg 0x10 to read */
+	}
+
+	if (rc == 0) {
+		/*
+		 * Read back reg 0x10. For hardware version 1 we must make
+		 * sure the absolute mode bit is set. For hardware version 2
+		 * the touchpad is probably initializing and not ready until
+		 * we read back the value we just wrote.
+		 */
+		do {
+			rc = elantech_read_reg(psmouse, 0x10, &val);
+			if (rc == 0)
+				break;
+			tries--;
+			elantech_debug("retrying read (%d).\n", tries);
+			msleep(ETP_READ_BACK_DELAY);
+		} while (tries > 0);
+
+		if (rc) {
+			psmouse_err(psmouse,
+				    "failed to read back register 0x10.\n");
+		} else if (etd->info.hw_version == 1 &&
+			   !(val & ETP_R10_ABSOLUTE_MODE)) {
+			psmouse_err(psmouse,
+				    "touchpad refuses to switch to absolute mode.\n");
+			rc = -1;
+		}
+	}
+
+ skip_readback_reg_10:
+	if (rc)
+		psmouse_err(psmouse, "failed to initialise registers.\n");
+
+	return rc;
+}
+
+/*
+ * (value from firmware) * 10 + 790 = dpi
+ * we also have to convert dpi to dots/mm (*10/254 to avoid floating point)
+ */
+static unsigned int elantech_convert_res(unsigned int val)
+{
+	return (val * 10 + 790) * 10 / 254;
+}
+
+static int elantech_get_resolution_v4(struct psmouse *psmouse,
+				      unsigned int *x_res,
+				      unsigned int *y_res,
+				      unsigned int *bus)
+{
+	unsigned char param[3];
+
+	if (elantech_send_cmd(psmouse, ETP_RESOLUTION_QUERY, param))
+		return -1;
+
+	*x_res = elantech_convert_res(param[1] & 0x0f);
+	*y_res = elantech_convert_res((param[1] & 0xf0) >> 4);
+	*bus = param[2];
+
+	return 0;
+}
+
+static void elantech_set_buttonpad_prop(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	struct elantech_data *etd = psmouse->private;
+
+	if (elantech_is_buttonpad(&etd->info)) {
+		__set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
+		__clear_bit(BTN_RIGHT, dev->keybit);
+	}
+}
+
+/*
+ * Some hw_version 4 models do have a middle button
+ */
+static const struct dmi_system_id elantech_dmi_has_middle_button[] = {
+#if defined(CONFIG_DMI) && defined(CONFIG_X86)
+	{
+		/* Fujitsu H730 has a middle button */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H730"),
+		},
+	},
+	{
+		/* Fujitsu H760 also has a middle button */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H760"),
+		},
+	},
+	{
+		/* Fujitsu H780 also has a middle button */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H780"),
+		},
+	},
+#endif
+	{ }
+};
+
+/*
+ * Set the appropriate event bits for the input subsystem
+ */
+static int elantech_set_input_params(struct psmouse *psmouse)
+{
+	struct input_dev *dev = psmouse->dev;
+	struct elantech_data *etd = psmouse->private;
+	struct elantech_device_info *info = &etd->info;
+	unsigned int x_min = info->x_min, y_min = info->y_min,
+		     x_max = info->x_max, y_max = info->y_max,
+		     width = info->width;
+
+	__set_bit(INPUT_PROP_POINTER, dev->propbit);
+	__set_bit(EV_KEY, dev->evbit);
+	__set_bit(EV_ABS, dev->evbit);
+	__clear_bit(EV_REL, dev->evbit);
+
+	__set_bit(BTN_LEFT, dev->keybit);
+	if (info->has_middle_button)
+		__set_bit(BTN_MIDDLE, dev->keybit);
+	__set_bit(BTN_RIGHT, dev->keybit);
+
+	__set_bit(BTN_TOUCH, dev->keybit);
+	__set_bit(BTN_TOOL_FINGER, dev->keybit);
+	__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
+	__set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
+
+	switch (info->hw_version) {
+	case 1:
+		/* Rocker button */
+		if (info->fw_version < 0x020000 &&
+		    (info->capabilities[0] & ETP_CAP_HAS_ROCKER)) {
+			__set_bit(BTN_FORWARD, dev->keybit);
+			__set_bit(BTN_BACK, dev->keybit);
+		}
+		input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
+		input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);
+		break;
+
+	case 2:
+		__set_bit(BTN_TOOL_QUADTAP, dev->keybit);
+		__set_bit(INPUT_PROP_SEMI_MT, dev->propbit);
+		fallthrough;
+	case 3:
+		if (info->hw_version == 3)
+			elantech_set_buttonpad_prop(psmouse);
+		input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
+		input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);
+		if (info->reports_pressure) {
+			input_set_abs_params(dev, ABS_PRESSURE, ETP_PMIN_V2,
+					     ETP_PMAX_V2, 0, 0);
+			input_set_abs_params(dev, ABS_TOOL_WIDTH, ETP_WMIN_V2,
+					     ETP_WMAX_V2, 0, 0);
+		}
+		input_mt_init_slots(dev, 2, INPUT_MT_SEMI_MT);
+		input_set_abs_params(dev, ABS_MT_POSITION_X, x_min, x_max, 0, 0);
+		input_set_abs_params(dev, ABS_MT_POSITION_Y, y_min, y_max, 0, 0);
+		break;
+
+	case 4:
+		elantech_set_buttonpad_prop(psmouse);
+		__set_bit(BTN_TOOL_QUADTAP, dev->keybit);
+		/* For X to recognize me as touchpad. */
+		input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
+		input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);
+		/*
+		 * range of pressure and width is the same as v2,
+		 * report ABS_PRESSURE, ABS_TOOL_WIDTH for compatibility.
+		 */
+		input_set_abs_params(dev, ABS_PRESSURE, ETP_PMIN_V2,
+				     ETP_PMAX_V2, 0, 0);
+		input_set_abs_params(dev, ABS_TOOL_WIDTH, ETP_WMIN_V2,
+				     ETP_WMAX_V2, 0, 0);
+		/* Multitouch capable pad, up to 5 fingers. */
+		input_mt_init_slots(dev, ETP_MAX_FINGERS, 0);
+		input_set_abs_params(dev, ABS_MT_POSITION_X, x_min, x_max, 0, 0);
+		input_set_abs_params(dev, ABS_MT_POSITION_Y, y_min, y_max, 0, 0);
+		input_set_abs_params(dev, ABS_MT_PRESSURE, ETP_PMIN_V2,
+				     ETP_PMAX_V2, 0, 0);
+		/*
+		 * The firmware reports how many trace lines the finger spans,
+		 * convert to surface unit as Protocol-B requires.
+		 */
+		input_set_abs_params(dev, ABS_MT_TOUCH_MAJOR, 0,
+				     ETP_WMAX_V2 * width, 0, 0);
+		break;
+	}
+
+	input_abs_set_res(dev, ABS_X, info->x_res);
+	input_abs_set_res(dev, ABS_Y, info->y_res);
+	if (info->hw_version > 1) {
+		input_abs_set_res(dev, ABS_MT_POSITION_X, info->x_res);
+		input_abs_set_res(dev, ABS_MT_POSITION_Y, info->y_res);
+	}
+
+	etd->y_max = y_max;
+	etd->width = width;
+
+	return 0;
+}
+
+struct elantech_attr_data {
+	size_t		field_offset;
+	unsigned char	reg;
+};
+
+/*
+ * Display a register value by reading a sysfs entry
+ */
+static ssize_t elantech_show_int_attr(struct psmouse *psmouse, void *data,
+					char *buf)
+{
+	struct elantech_data *etd = psmouse->private;
+	struct elantech_attr_data *attr = data;
+	unsigned char *reg = (unsigned char *) etd + attr->field_offset;
+	int rc = 0;
+
+	if (attr->reg)
+		rc = elantech_read_reg(psmouse, attr->reg, reg);
+
+	return sprintf(buf, "0x%02x\n", (attr->reg && rc) ? -1 : *reg);
+}
+
+/*
+ * Write a register value by writing a sysfs entry
+ */
+static ssize_t elantech_set_int_attr(struct psmouse *psmouse,
+				     void *data, const char *buf, size_t count)
+{
+	struct elantech_data *etd = psmouse->private;
+	struct elantech_attr_data *attr = data;
+	unsigned char *reg = (unsigned char *) etd + attr->field_offset;
+	unsigned char value;
+	int err;
+
+	err = kstrtou8(buf, 16, &value);
+	if (err)
+		return err;
+
+	/* Do we need to preserve some bits for version 2 hardware too? */
+	if (etd->info.hw_version == 1) {
+		if (attr->reg == 0x10)
+			/* Force absolute mode always on */
+			value |= ETP_R10_ABSOLUTE_MODE;
+		else if (attr->reg == 0x11)
+			/* Force 4 byte mode always on */
+			value |= ETP_R11_4_BYTE_MODE;
+	}
+
+	if (!attr->reg || elantech_write_reg(psmouse, attr->reg, value) == 0)
+		*reg = value;
+
+	return count;
+}
+
+#define ELANTECH_INT_ATTR(_name, _register)				\
+	static struct elantech_attr_data elantech_attr_##_name = {	\
+		.field_offset = offsetof(struct elantech_data, _name),	\
+		.reg = _register,					\
+	};								\
+	PSMOUSE_DEFINE_ATTR(_name, 0644,				\
+			    &elantech_attr_##_name,			\
+			    elantech_show_int_attr,			\
+			    elantech_set_int_attr)
+
+#define ELANTECH_INFO_ATTR(_name)					       \
+	static struct elantech_attr_data elantech_attr_##_name = {	       \
+		.field_offset = offsetof(struct elantech_data, info) +	       \
+				offsetof(struct elantech_device_info, _name),  \
+		.reg = 0,						       \
+	};								       \
+	PSMOUSE_DEFINE_ATTR(_name, 0644,				       \
+			    &elantech_attr_##_name,			       \
+			    elantech_show_int_attr,			       \
+			    elantech_set_int_attr)
+
+ELANTECH_INT_ATTR(reg_07, 0x07);
+ELANTECH_INT_ATTR(reg_10, 0x10);
+ELANTECH_INT_ATTR(reg_11, 0x11);
+ELANTECH_INT_ATTR(reg_20, 0x20);
+ELANTECH_INT_ATTR(reg_21, 0x21);
+ELANTECH_INT_ATTR(reg_22, 0x22);
+ELANTECH_INT_ATTR(reg_23, 0x23);
+ELANTECH_INT_ATTR(reg_24, 0x24);
+ELANTECH_INT_ATTR(reg_25, 0x25);
+ELANTECH_INT_ATTR(reg_26, 0x26);
+ELANTECH_INFO_ATTR(debug);
+ELANTECH_INFO_ATTR(paritycheck);
+ELANTECH_INFO_ATTR(crc_enabled);
+
+static struct attribute *elantech_attrs[] = {
+	&psmouse_attr_reg_07.dattr.attr,
+	&psmouse_attr_reg_10.dattr.attr,
+	&psmouse_attr_reg_11.dattr.attr,
+	&psmouse_attr_reg_20.dattr.attr,
+	&psmouse_attr_reg_21.dattr.attr,
+	&psmouse_attr_reg_22.dattr.attr,
+	&psmouse_attr_reg_23.dattr.attr,
+	&psmouse_attr_reg_24.dattr.attr,
+	&psmouse_attr_reg_25.dattr.attr,
+	&psmouse_attr_reg_26.dattr.attr,
+	&psmouse_attr_debug.dattr.attr,
+	&psmouse_attr_paritycheck.dattr.attr,
+	&psmouse_attr_crc_enabled.dattr.attr,
+	NULL
+};
+
+static const struct attribute_group elantech_attr_group = {
+	.attrs = elantech_attrs,
+};
+
+static bool elantech_is_signature_valid(const unsigned char *param)
+{
+	static const unsigned char rates[] = { 200, 100, 80, 60, 40, 20, 10 };
+	int i;
+
+	if (param[0] == 0)
+		return false;
+
+	if (param[1] == 0)
+		return true;
+
+	/*
+	 * Some hw_version >= 4 models have a revision higher then 20. Meaning
+	 * that param[2] may be 10 or 20, skip the rates check for these.
+	 */
+	if ((param[0] & 0x0f) >= 0x06 && (param[1] & 0xaf) == 0x0f &&
+	    param[2] < 40)
+		return true;
+
+	for (i = 0; i < ARRAY_SIZE(rates); i++)
+		if (param[2] == rates[i])
+			return false;
+
+	return true;
+}
+
+/*
+ * Use magic knock to detect Elantech touchpad
+ */
+int elantech_detect(struct psmouse *psmouse, bool set_properties)
+{
+	struct ps2dev *ps2dev = &psmouse->ps2dev;
+	unsigned char param[3];
+
+	ps2_command(ps2dev, NULL, PSMOUSE_CMD_RESET_DIS);
+
+	if (ps2_command(ps2dev,  NULL, PSMOUSE_CMD_DISABLE) ||
+	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
+	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
+	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
+	    ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
+		psmouse_dbg(psmouse, "sending Elantech magic knock failed.\n");
+		return -1;
+	}
+
+	/*
+	 * Report this in case there are Elantech models that use a different
+	 * set of magic numbers
+	 */
+	if (param[0] != 0x3c || param[1] != 0x03 ||
+	    (param[2] != 0xc8 && param[2] != 0x00)) {
+		psmouse_dbg(psmouse,
+			    "unexpected magic knock result 0x%02x, 0x%02x, 0x%02x.\n",
+			    param[0], param[1], param[2]);
+		return -1;
+	}
+
+	/*
+	 * Query touchpad's firmware version and see if it reports known
+	 * value to avoid mis-detection. Logitech mice are known to respond
+	 * to Elantech magic knock and there might be more.
+	 */
+	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
+		psmouse_dbg(psmouse, "failed to query firmware version.\n");
+		return -1;
+	}
+
+	psmouse_dbg(psmouse,
+		    "Elantech version query result 0x%02x, 0x%02x, 0x%02x.\n",
+		    param[0], param[1], param[2]);
+
+	if (!elantech_is_signature_valid(param)) {
+		psmouse_dbg(psmouse,
+			    "Probably not a real Elantech touchpad. Aborting.\n");
+		return -1;
+	}
+
+	if (set_properties) {
+		psmouse->vendor = "Elantech";
+		psmouse->name = "Touchpad";
+	}
+
+	return 0;
+}
+
+/*
+ * Clean up sysfs entries when disconnecting
+ */
+static void elantech_disconnect(struct psmouse *psmouse)
+{
+	struct elantech_data *etd = psmouse->private;
+
+	/*
+	 * We might have left a breadcrumb when trying to
+	 * set up SMbus companion.
+	 */
+	psmouse_smbus_cleanup(psmouse);
+
+	if (etd->tp_dev)
+		input_unregister_device(etd->tp_dev);
+	sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj,
+			   &elantech_attr_group);
+	kfree(psmouse->private);
+	psmouse->private = NULL;
+}
+
+/*
+ * Some hw_version 4 models fail to properly activate absolute mode on
+ * resume without going through disable/enable cycle.
+ */
+static const struct dmi_system_id elantech_needs_reenable[] = {
+#if defined(CONFIG_DMI) && defined(CONFIG_X86)
+	{
+		/* Lenovo N24 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "81AF"),
+		},
+	},
+#endif
+	{ }
+};
+
+/*
+ * Put the touchpad back into absolute mode when reconnecting
+ */
+static int elantech_reconnect(struct psmouse *psmouse)
+{
+	int err;
+
+	psmouse_reset(psmouse);
+
+	if (elantech_detect(psmouse, 0))
+		return -1;
+
+	if (dmi_check_system(elantech_needs_reenable)) {
+		err = ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_DISABLE);
+		if (err)
+			psmouse_warn(psmouse, "failed to deactivate mouse on %s: %d\n",
+				     psmouse->ps2dev.serio->phys, err);
+
+		err = ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_ENABLE);
+		if (err)
+			psmouse_warn(psmouse, "failed to reactivate mouse on %s: %d\n",
+				     psmouse->ps2dev.serio->phys, err);
+	}
+
+	if (elantech_set_absolute_mode(psmouse)) {
+		psmouse_err(psmouse,
+			    "failed to put touchpad back into absolute mode.\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * Some hw_version 4 models do not work with crc_disabled
+ */
+static const struct dmi_system_id elantech_dmi_force_crc_enabled[] = {
+#if defined(CONFIG_DMI) && defined(CONFIG_X86)
+	{
+		/* Fujitsu H730 does not work with crc_enabled == 0 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H730"),
+		},
+	},
+	{
+		/* Fujitsu H760 does not work with crc_enabled == 0 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H760"),
+		},
+	},
+	{
+		/* Fujitsu LIFEBOOK E544  does not work with crc_enabled == 0 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E544"),
+		},
+	},
+	{
+		/* Fujitsu LIFEBOOK E546  does not work with crc_enabled == 0 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E546"),
+		},
+	},
+	{
+		/* Fujitsu LIFEBOOK E547 does not work with crc_enabled == 0 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E547"),
+		},
+	},
+	{
+		/* Fujitsu LIFEBOOK E554  does not work with crc_enabled == 0 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E554"),
+		},
+	},
+	{
+		/* Fujitsu LIFEBOOK E556 does not work with crc_enabled == 0 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E556"),
+		},
+	},
+	{
+		/* Fujitsu LIFEBOOK E557 does not work with crc_enabled == 0 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E557"),
+		},
+	},
+	{
+		/* Fujitsu LIFEBOOK U745 does not work with crc_enabled == 0 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK U745"),
+		},
+	},
+#endif
+	{ }
+};
+
+/*
+ * Some hw_version 3 models go into error state when we try to set
+ * bit 3 and/or bit 1 of r10.
+ */
+static const struct dmi_system_id no_hw_res_dmi_table[] = {
+#if defined(CONFIG_DMI) && defined(CONFIG_X86)
+	{
+		/* Gigabyte U2442 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "GIGABYTE"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "U2442"),
+		},
+	},
+#endif
+	{ }
+};
+
+/*
+ * Change Report id 0x5E to 0x5F.
+ */
+static int elantech_change_report_id(struct psmouse *psmouse)
+{
+	/*
+	 * NOTE: the code is expecting to receive param[] as an array of 3
+	 * items (see __ps2_command()), even if in this case only 2 are
+	 * actually needed. Make sure the array size is 3 to avoid potential
+	 * stack out-of-bound accesses.
+	 */
+	unsigned char param[3] = { 0x10, 0x03 };
+
+	if (elantech_write_reg_params(psmouse, 0x7, param) ||
+	    elantech_read_reg_params(psmouse, 0x7, param) ||
+	    param[0] != 0x10 || param[1] != 0x03) {
+		psmouse_err(psmouse, "Unable to change report ID to 0x5f.\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+/*
+ * determine hardware version and set some properties according to it.
+ */
+static int elantech_set_properties(struct elantech_device_info *info)
+{
+	/* This represents the version of IC body. */
+	info->ic_version = (info->fw_version & 0x0f0000) >> 16;
+
+	/* Early version of Elan touchpads doesn't obey the rule. */
+	if (info->fw_version < 0x020030 || info->fw_version == 0x020600)
+		info->hw_version = 1;
+	else {
+		switch (info->ic_version) {
+		case 2:
+		case 4:
+			info->hw_version = 2;
+			break;
+		case 5:
+			info->hw_version = 3;
+			break;
+		case 6 ... 15:
+			info->hw_version = 4;
+			break;
+		default:
+			return -1;
+		}
+	}
+
+	/* Get information pattern for hw_version 4 */
+	info->pattern = 0x00;
+	if (info->ic_version == 0x0f && (info->fw_version & 0xff) <= 0x02)
+		info->pattern = info->fw_version & 0xff;
+
+	/* decide which send_cmd we're gonna use early */
+	info->send_cmd = info->hw_version >= 3 ? elantech_send_cmd :
+						 synaptics_send_cmd;
+
+	/* Turn on packet checking by default */
+	info->paritycheck = 1;
+
+	/*
+	 * This firmware suffers from misreporting coordinates when
+	 * a touch action starts causing the mouse cursor or scrolled page
+	 * to jump. Enable a workaround.
+	 */
+	info->jumpy_cursor =
+		(info->fw_version == 0x020022 || info->fw_version == 0x020600);
+
+	if (info->hw_version > 1) {
+		/* For now show extra debug information */
+		info->debug = 1;
+
+		if (info->fw_version >= 0x020800)
+			info->reports_pressure = true;
+	}
+
+	/*
+	 * The signatures of v3 and v4 packets change depending on the
+	 * value of this hardware flag.
+	 */
+	info->crc_enabled = (info->fw_version & 0x4000) == 0x4000 ||
+			     dmi_check_system(elantech_dmi_force_crc_enabled);
+
+	/* Enable real hardware resolution on hw_version 3 ? */
+	info->set_hw_resolution = !dmi_check_system(no_hw_res_dmi_table);
+
+	return 0;
+}
+
+static int elantech_query_info(struct psmouse *psmouse,
+			       struct elantech_device_info *info)
+{
+	unsigned char param[3];
+	unsigned char traces;
+	unsigned char ic_body[3];
+
+	memset(info, 0, sizeof(*info));
+
+	/*
+	 * Do the version query again so we can store the result
+	 */
+	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
+		psmouse_err(psmouse, "failed to query firmware version.\n");
+		return -EINVAL;
+	}
+	info->fw_version = (param[0] << 16) | (param[1] << 8) | param[2];
+
+	if (elantech_set_properties(info)) {
+		psmouse_err(psmouse, "unknown hardware version, aborting...\n");
+		return -EINVAL;
+	}
+	psmouse_info(psmouse,
+		     "assuming hardware version %d (with firmware version 0x%02x%02x%02x)\n",
+		     info->hw_version, param[0], param[1], param[2]);
+
+	if (info->send_cmd(psmouse, ETP_CAPABILITIES_QUERY,
+	    info->capabilities)) {
+		psmouse_err(psmouse, "failed to query capabilities.\n");
+		return -EINVAL;
+	}
+	psmouse_info(psmouse,
+		     "Synaptics capabilities query result 0x%02x, 0x%02x, 0x%02x.\n",
+		     info->capabilities[0], info->capabilities[1],
+		     info->capabilities[2]);
+
+	if (info->hw_version != 1) {
+		if (info->send_cmd(psmouse, ETP_SAMPLE_QUERY, info->samples)) {
+			psmouse_err(psmouse, "failed to query sample data\n");
+			return -EINVAL;
+		}
+		psmouse_info(psmouse,
+			     "Elan sample query result %02x, %02x, %02x\n",
+			     info->samples[0],
+			     info->samples[1],
+			     info->samples[2]);
+	}
+
+	if (info->pattern > 0x00 && info->ic_version == 0xf) {
+		if (info->send_cmd(psmouse, ETP_ICBODY_QUERY, ic_body)) {
+			psmouse_err(psmouse, "failed to query ic body\n");
+			return -EINVAL;
+		}
+		info->ic_version = be16_to_cpup((__be16 *)ic_body);
+		psmouse_info(psmouse,
+			     "Elan ic body: %#04x, current fw version: %#02x\n",
+			     info->ic_version, ic_body[2]);
+	}
+
+	info->product_id = be16_to_cpup((__be16 *)info->samples);
+	if (info->pattern == 0x00)
+		info->product_id &= 0xff;
+
+	if (info->samples[1] == 0x74 && info->hw_version == 0x03) {
+		/*
+		 * This module has a bug which makes absolute mode
+		 * unusable, so let's abort so we'll be using standard
+		 * PS/2 protocol.
+		 */
+		psmouse_info(psmouse,
+			     "absolute mode broken, forcing standard PS/2 protocol\n");
+		return -ENODEV;
+	}
+
+	/* The MSB indicates the presence of the trackpoint */
+	info->has_trackpoint = (info->capabilities[0] & 0x80) == 0x80;
+
+	if (info->has_trackpoint && info->ic_version == 0x0011 &&
+	    (info->product_id == 0x08 || info->product_id == 0x09 ||
+	     info->product_id == 0x0d || info->product_id == 0x0e)) {
+		/*
+		 * This module has a bug which makes trackpoint in SMBus
+		 * mode return invalid data unless trackpoint is switched
+		 * from using 0x5e reports to 0x5f. If we are not able to
+		 * make the switch, let's abort initialization so we'll be
+		 * using standard PS/2 protocol.
+		 */
+		if (elantech_change_report_id(psmouse)) {
+			psmouse_info(psmouse,
+				     "Trackpoint report is broken, forcing standard PS/2 protocol\n");
+			return -ENODEV;
+		}
+	}
+
+	info->x_res = 31;
+	info->y_res = 31;
+	if (info->hw_version == 4) {
+		if (elantech_get_resolution_v4(psmouse,
+					       &info->x_res,
+					       &info->y_res,
+					       &info->bus)) {
+			psmouse_warn(psmouse,
+				     "failed to query resolution data.\n");
+		}
+	}
+
+	/* query range information */
+	switch (info->hw_version) {
+	case 1:
+		info->x_min = ETP_XMIN_V1;
+		info->y_min = ETP_YMIN_V1;
+		info->x_max = ETP_XMAX_V1;
+		info->y_max = ETP_YMAX_V1;
+		break;
+
+	case 2:
+		if (info->fw_version == 0x020800 ||
+		    info->fw_version == 0x020b00 ||
+		    info->fw_version == 0x020030) {
+			info->x_min = ETP_XMIN_V2;
+			info->y_min = ETP_YMIN_V2;
+			info->x_max = ETP_XMAX_V2;
+			info->y_max = ETP_YMAX_V2;
+		} else {
+			int i;
+			int fixed_dpi;
+
+			i = (info->fw_version > 0x020800 &&
+			     info->fw_version < 0x020900) ? 1 : 2;
+
+			if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
+				return -EINVAL;
+
+			fixed_dpi = param[1] & 0x10;
+
+			if (((info->fw_version >> 16) == 0x14) && fixed_dpi) {
+				if (info->send_cmd(psmouse, ETP_SAMPLE_QUERY, param))
+					return -EINVAL;
+
+				info->x_max = (info->capabilities[1] - i) * param[1] / 2;
+				info->y_max = (info->capabilities[2] - i) * param[2] / 2;
+			} else if (info->fw_version == 0x040216) {
+				info->x_max = 819;
+				info->y_max = 405;
+			} else if (info->fw_version == 0x040219 || info->fw_version == 0x040215) {
+				info->x_max = 900;
+				info->y_max = 500;
+			} else {
+				info->x_max = (info->capabilities[1] - i) * 64;
+				info->y_max = (info->capabilities[2] - i) * 64;
+			}
+		}
+		break;
+
+	case 3:
+		if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
+			return -EINVAL;
+
+		info->x_max = (0x0f & param[0]) << 8 | param[1];
+		info->y_max = (0xf0 & param[0]) << 4 | param[2];
+		break;
+
+	case 4:
+		if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
+			return -EINVAL;
+
+		info->x_max = (0x0f & param[0]) << 8 | param[1];
+		info->y_max = (0xf0 & param[0]) << 4 | param[2];
+		traces = info->capabilities[1];
+		if ((traces < 2) || (traces > info->x_max))
+			return -EINVAL;
+
+		info->width = info->x_max / (traces - 1);
+
+		/* column number of traces */
+		info->x_traces = traces;
+
+		/* row number of traces */
+		traces = info->capabilities[2];
+		if ((traces >= 2) && (traces <= info->y_max))
+			info->y_traces = traces;
+
+		break;
+	}
+
+	/* check for the middle button: DMI matching or new v4 firmwares */
+	info->has_middle_button = dmi_check_system(elantech_dmi_has_middle_button) ||
+				  (ETP_NEW_IC_SMBUS_HOST_NOTIFY(info->fw_version) &&
+				   !elantech_is_buttonpad(info));
+
+	return 0;
+}
+
+#if defined(CONFIG_MOUSE_PS2_ELANTECH_SMBUS)
+
+/*
+ * The newest Elantech device can use a secondary bus (over SMBus) which
+ * provides a better bandwidth and allow a better control of the touchpads.
+ * This is used to decide if we need to use this bus or not.
+ */
+enum {
+	ELANTECH_SMBUS_NOT_SET = -1,
+	ELANTECH_SMBUS_OFF,
+	ELANTECH_SMBUS_ON,
+};
+
+static int elantech_smbus = IS_ENABLED(CONFIG_MOUSE_ELAN_I2C_SMBUS) ?
+		ELANTECH_SMBUS_NOT_SET : ELANTECH_SMBUS_OFF;
+module_param_named(elantech_smbus, elantech_smbus, int, 0644);
+MODULE_PARM_DESC(elantech_smbus, "Use a secondary bus for the Elantech device.");
+
+static const char * const i2c_blacklist_pnp_ids[] = {
+	/*
+	 * These are known to not be working properly as bits are missing
+	 * in elan_i2c.
+	 */
+	NULL
+};
+
+static int elantech_create_smbus(struct psmouse *psmouse,
+				 struct elantech_device_info *info,
+				 bool leave_breadcrumbs)
+{
+	struct property_entry i2c_props[11] = {};
+	struct i2c_board_info smbus_board = {
+		I2C_BOARD_INFO("elan_i2c", 0x15),
+		.flags = I2C_CLIENT_HOST_NOTIFY,
+	};
+	unsigned int idx = 0;
+
+	i2c_props[idx++] = PROPERTY_ENTRY_U32("touchscreen-size-x",
+						   info->x_max + 1);
+	i2c_props[idx++] = PROPERTY_ENTRY_U32("touchscreen-size-y",
+						   info->y_max + 1);
+	i2c_props[idx++] = PROPERTY_ENTRY_U32("touchscreen-min-x",
+						   info->x_min);
+	i2c_props[idx++] = PROPERTY_ENTRY_U32("touchscreen-min-y",
+						   info->y_min);
+	if (info->x_res)
+		i2c_props[idx++] = PROPERTY_ENTRY_U32("touchscreen-x-mm",
+						      (info->x_max + 1) / info->x_res);
+	if (info->y_res)
+		i2c_props[idx++] = PROPERTY_ENTRY_U32("touchscreen-y-mm",
+						      (info->y_max + 1) / info->y_res);
+
+	if (info->has_trackpoint)
+		i2c_props[idx++] = PROPERTY_ENTRY_BOOL("elan,trackpoint");
+
+	if (info->has_middle_button)
+		i2c_props[idx++] = PROPERTY_ENTRY_BOOL("elan,middle-button");
+
+	if (info->x_traces)
+		i2c_props[idx++] = PROPERTY_ENTRY_U32("elan,x_traces",
+						      info->x_traces);
+	if (info->y_traces)
+		i2c_props[idx++] = PROPERTY_ENTRY_U32("elan,y_traces",
+						      info->y_traces);
+
+	if (elantech_is_buttonpad(info))
+		i2c_props[idx++] = PROPERTY_ENTRY_BOOL("elan,clickpad");
+
+	smbus_board.fwnode = fwnode_create_software_node(i2c_props, NULL);
+	if (IS_ERR(smbus_board.fwnode))
+		return PTR_ERR(smbus_board.fwnode);
+
+	return psmouse_smbus_init(psmouse, &smbus_board, NULL, 0, false,
+				  leave_breadcrumbs);
+}
+
+/*
+ * elantech_setup_smbus - called once the PS/2 devices are enumerated
+ * and decides to instantiate a SMBus InterTouch device.
+ */
+static int elantech_setup_smbus(struct psmouse *psmouse,
+				struct elantech_device_info *info,
+				bool leave_breadcrumbs)
+{
+	int error;
+
+	if (elantech_smbus == ELANTECH_SMBUS_OFF)
+		return -ENXIO;
+
+	if (elantech_smbus == ELANTECH_SMBUS_NOT_SET) {
+		/*
+		 * New ICs are enabled by default, unless mentioned in
+		 * i2c_blacklist_pnp_ids.
+		 * Old ICs are up to the user to decide.
+		 */
+		if (!ETP_NEW_IC_SMBUS_HOST_NOTIFY(info->fw_version) ||
+		    psmouse_matches_pnp_id(psmouse, i2c_blacklist_pnp_ids))
+			return -ENXIO;
+	}
+
+	psmouse_info(psmouse, "Trying to set up SMBus access\n");
+
+	error = elantech_create_smbus(psmouse, info, leave_breadcrumbs);
+	if (error) {
+		if (error == -EAGAIN)
+			psmouse_info(psmouse, "SMbus companion is not ready yet\n");
+		else
+			psmouse_err(psmouse, "unable to create intertouch device\n");
+
+		return error;
+	}
+
+	return 0;
+}
+
+static bool elantech_use_host_notify(struct psmouse *psmouse,
+				     struct elantech_device_info *info)
+{
+	if (ETP_NEW_IC_SMBUS_HOST_NOTIFY(info->fw_version))
+		return true;
+
+	switch (info->bus) {
+	case ETP_BUS_PS2_ONLY:
+		/* expected case */
+		break;
+	case ETP_BUS_SMB_ALERT_ONLY:
+	case ETP_BUS_PS2_SMB_ALERT:
+		psmouse_dbg(psmouse, "Ignoring SMBus provider through alert protocol.\n");
+		break;
+	case ETP_BUS_SMB_HST_NTFY_ONLY:
+	case ETP_BUS_PS2_SMB_HST_NTFY:
+		return true;
+	default:
+		psmouse_dbg(psmouse,
+			    "Ignoring SMBus bus provider %d.\n",
+			    info->bus);
+	}
+
+	return false;
+}
+
+int elantech_init_smbus(struct psmouse *psmouse)
+{
+	struct elantech_device_info info;
+	int error;
+
+	psmouse_reset(psmouse);
+
+	error = elantech_query_info(psmouse, &info);
+	if (error)
+		goto init_fail;
+
+	if (info.hw_version < 4) {
+		error = -ENXIO;
+		goto init_fail;
+	}
+
+	return elantech_create_smbus(psmouse, &info, false);
+ init_fail:
+	psmouse_reset(psmouse);
+	return error;
+}
+#endif /* CONFIG_MOUSE_PS2_ELANTECH_SMBUS */
+
+/*
+ * Initialize the touchpad and create sysfs entries
+ */
+static int elantech_setup_ps2(struct psmouse *psmouse,
+			      struct elantech_device_info *info)
+{
+	struct elantech_data *etd;
+	int i;
+	int error = -EINVAL;
+	struct input_dev *tp_dev;
+
+	psmouse->private = etd = kzalloc_obj(*etd);
+	if (!etd)
+		return -ENOMEM;
+
+	etd->info = *info;
+
+	etd->parity[0] = 1;
+	for (i = 1; i < 256; i++)
+		etd->parity[i] = etd->parity[i & (i - 1)] ^ 1;
+
+	if (elantech_set_absolute_mode(psmouse)) {
+		psmouse_err(psmouse,
+			    "failed to put touchpad into absolute mode.\n");
+		goto init_fail;
+	}
+
+	if (info->fw_version == 0x381f17) {
+		etd->original_set_rate = psmouse->set_rate;
+		psmouse->set_rate = elantech_set_rate_restore_reg_07;
+	}
+
+	if (elantech_set_input_params(psmouse)) {
+		psmouse_err(psmouse, "failed to query touchpad range.\n");
+		goto init_fail;
+	}
+
+	error = sysfs_create_group(&psmouse->ps2dev.serio->dev.kobj,
+				   &elantech_attr_group);
+	if (error) {
+		psmouse_err(psmouse,
+			    "failed to create sysfs attributes, error: %d.\n",
+			    error);
+		goto init_fail;
+	}
+
+	if (info->has_trackpoint) {
+		tp_dev = input_allocate_device();
+
+		if (!tp_dev) {
+			error = -ENOMEM;
+			goto init_fail_tp_alloc;
+		}
+
+		etd->tp_dev = tp_dev;
+		snprintf(etd->tp_phys, sizeof(etd->tp_phys), "%s/input1",
+			psmouse->ps2dev.serio->phys);
+		tp_dev->phys = etd->tp_phys;
+		tp_dev->name = "ETPS/2 Elantech TrackPoint";
+		tp_dev->id.bustype = BUS_I8042;
+		tp_dev->id.vendor  = 0x0002;
+		tp_dev->id.product = PSMOUSE_ELANTECH;
+		tp_dev->id.version = 0x0000;
+		tp_dev->dev.parent = &psmouse->ps2dev.serio->dev;
+		tp_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL);
+		tp_dev->relbit[BIT_WORD(REL_X)] =
+			BIT_MASK(REL_X) | BIT_MASK(REL_Y);
+		tp_dev->keybit[BIT_WORD(BTN_LEFT)] =
+			BIT_MASK(BTN_LEFT) | BIT_MASK(BTN_MIDDLE) |
+			BIT_MASK(BTN_RIGHT);
+
+		__set_bit(INPUT_PROP_POINTER, tp_dev->propbit);
+		__set_bit(INPUT_PROP_POINTING_STICK, tp_dev->propbit);
+
+		error = input_register_device(etd->tp_dev);
+		if (error < 0)
+			goto init_fail_tp_reg;
+	}
+
+	psmouse->protocol_handler = elantech_process_byte;
+	psmouse->disconnect = elantech_disconnect;
+	psmouse->reconnect = elantech_reconnect;
+	psmouse->fast_reconnect = NULL;
+	psmouse->pktsize = info->hw_version > 1 ? 6 : 4;
+
+	return 0;
+ init_fail_tp_reg:
+	input_free_device(tp_dev);
+ init_fail_tp_alloc:
+	sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj,
+			   &elantech_attr_group);
+ init_fail:
+	kfree(etd);
+	return error;
+}
+
+int elantech_init_ps2(struct psmouse *psmouse)
+{
+	struct elantech_device_info info;
+	int error;
+
+	psmouse_reset(psmouse);
+
+	error = elantech_query_info(psmouse, &info);
+	if (error)
+		goto init_fail;
+
+	error = elantech_setup_ps2(psmouse, &info);
+	if (error)
+		goto init_fail;
+
+	return 0;
+ init_fail:
+	psmouse_reset(psmouse);
+	return error;
+}
+
+int elantech_init(struct psmouse *psmouse)
+{
+	struct elantech_device_info info;
+	int error;
+
+	psmouse_reset(psmouse);
+
+	error = elantech_query_info(psmouse, &info);
+	if (error)
+		goto init_fail;
+
+#if defined(CONFIG_MOUSE_PS2_ELANTECH_SMBUS)
+
+	if (elantech_use_host_notify(psmouse, &info)) {
+		if (!IS_ENABLED(CONFIG_MOUSE_ELAN_I2C_SMBUS) ||
+		    !IS_ENABLED(CONFIG_MOUSE_PS2_ELANTECH_SMBUS)) {
+			psmouse_warn(psmouse,
+				     "The touchpad can support a better bus than the too old PS/2 protocol. "
+				     "Make sure MOUSE_PS2_ELANTECH_SMBUS and MOUSE_ELAN_I2C_SMBUS are enabled to get a better touchpad experience.\n");
+		}
+		error = elantech_setup_smbus(psmouse, &info, true);
+		if (!error)
+			return PSMOUSE_ELANTECH_SMBUS;
+	}
+
+#endif /* CONFIG_MOUSE_PS2_ELANTECH_SMBUS */
+
+	error = elantech_setup_ps2(psmouse, &info);
+	if (error < 0) {
+		/*
+		 * Not using any flavor of Elantech support, so clean up
+		 * SMbus breadcrumbs, if any.
+		 */
+		psmouse_smbus_cleanup(psmouse);
+		goto init_fail;
+	}
+
+	return PSMOUSE_ELANTECH;
+ init_fail:
+	psmouse_reset(psmouse);
+	return error;
+}