Input: add support for Elan eKTH I2C touchscreens

This driver supports Elan eKTH I2C touchscreen controllers. Note that these
are using custom protocol, as opposed to other Elan parts that use
HID-over-I2C and are supported by the standard HID-multitouch driver.

Signed-off-by: Scott Liu <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

Documentation/devicetree/bindings/input/elants_i2c.txt

···
+Elantech I2C Touchscreen
+
+Required properties:
+- compatible: must be "elan,ekth3500".
+- reg: I2C address of the chip.
+- interrupt-parent: a phandle for the interrupt controller (see interrupt
+  binding[0]).
+- interrupts: interrupt to which the chip is connected (see interrupt
+  binding[0]).
+
+Optional properties:
+- wakeup-source: touchscreen can be used as a wakeup source.
+- pinctrl-names: should be "default" (see pinctrl binding [1]).
+- pinctrl-0: a phandle pointing to the pin settings for the device (see
+  pinctrl binding [1]).
+
+[0]: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
+[1]: Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
+
+Example:
+	&i2c1 {
+		/* ... */
+
+		touchscreen@10 {
+			compatible = "elan,ekth3500";
+			reg = <0x10>;
+			interrupt-parent = <&gpio4>;
+			interrupts = <0x0 IRQ_TYPE_EDGE_FALLING>;
+			wakeup-source;
+		};
+
+		/* ... */
+	};

drivers/input/touchscreen/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called gunze.
 
+config TOUCHSCREEN_ELAN
+	tristate "Elan eKTH I2C touchscreen"
+	depends on I2C
+	help
+	  Say Y here if you have an Elan eKTH I2C touchscreen
+	  connected to your system.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called elants_i2c.
+
 config TOUCHSCREEN_ELO
 	tristate "Elo serial touchscreens"
 	select SERIO

drivers/input/touchscreen/Makefile

···
 obj-$(CONFIG_TOUCHSCREEN_HAMPSHIRE)	+= hampshire.o
 obj-$(CONFIG_TOUCHSCREEN_GUNZE)		+= gunze.o
 obj-$(CONFIG_TOUCHSCREEN_EETI)		+= eeti_ts.o
+obj-$(CONFIG_TOUCHSCREEN_ELAN)		+= elants_i2c.o
 obj-$(CONFIG_TOUCHSCREEN_ELO)		+= elo.o
 obj-$(CONFIG_TOUCHSCREEN_EGALAX)	+= egalax_ts.o
 obj-$(CONFIG_TOUCHSCREEN_FUJITSU)	+= fujitsu_ts.o

drivers/input/touchscreen/elants_i2c.c

···
+/*
+ * Elan Microelectronics touch panels with I2C interface
+ *
+ * Copyright (C) 2014 Elan Microelectronics Corporation.
+ * Scott Liu <[e-mail]>
+ *
+ * This code is partly based on hid-multitouch.c:
+ *
+ *  Copyright (c) 2010-2012 Stephane Chatty <[e-mail]>
+ *  Copyright (c) 2010-2012 Benjamin Tissoires <[e-mail]>
+ *  Copyright (c) 2010-2012 Ecole Nationale de l'Aviation Civile, France
+ *
+ *
+ * This code is partly based on i2c-hid.c:
+ *
+ * Copyright (c) 2012 Benjamin Tissoires <[e-mail]>
+ * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
+ * Copyright (c) 2012 Red Hat, Inc
+ */
+
+/*
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ */
+
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/async.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/uaccess.h>
+#include <linux/buffer_head.h>
+#include <linux/version.h>
+#include <linux/slab.h>
+#include <linux/firmware.h>
+#include <linux/version.h>
+#include <linux/input/mt.h>
+#include <linux/acpi.h>
+#include <linux/of.h>
+#include <asm/unaligned.h>
+
+/* Device, Driver information */
+#define DEVICE_NAME	"elants_i2c"
+#define DRV_VERSION	"1.0.9"
+
+/* Convert from rows or columns into resolution */
+#define ELAN_TS_RESOLUTION(n, m)   (((n) - 1) * (m))
+
+/* FW header data */
+#define HEADER_SIZE		4
+#define FW_HDR_TYPE		0
+#define FW_HDR_COUNT		1
+#define FW_HDR_LENGTH		2
+
+/* Buffer mode Queue Header information */
+#define QUEUE_HEADER_SINGLE	0x62
+#define QUEUE_HEADER_NORMAL	0X63
+#define QUEUE_HEADER_WAIT	0x64
+
+/* Command header definition */
+#define CMD_HEADER_WRITE	0x54
+#define CMD_HEADER_READ		0x53
+#define CMD_HEADER_6B_READ	0x5B
+#define CMD_HEADER_RESP		0x52
+#define CMD_HEADER_6B_RESP	0x9B
+#define CMD_HEADER_HELLO	0x55
+#define CMD_HEADER_REK		0x66
+
+/* FW position data */
+#define PACKET_SIZE		55
+#define MAX_CONTACT_NUM		10
+#define FW_POS_HEADER		0
+#define FW_POS_STATE		1
+#define FW_POS_TOTAL		2
+#define FW_POS_XY		3
+#define FW_POS_CHECKSUM		34
+#define FW_POS_WIDTH		35
+#define FW_POS_PRESSURE		45
+
+#define HEADER_REPORT_10_FINGER	0x62
+
+/* Header (4 bytes) plus 3 fill 10-finger packets */
+#define MAX_PACKET_SIZE		169
+
+#define BOOT_TIME_DELAY_MS	50
+
+/* FW read command, 0x53 0x?? 0x0, 0x01 */
+#define E_ELAN_INFO_FW_VER	0x00
+#define E_ELAN_INFO_BC_VER	0x10
+#define E_ELAN_INFO_TEST_VER	0xE0
+#define E_ELAN_INFO_FW_ID	0xF0
+#define E_INFO_OSR		0xD6
+#define E_INFO_PHY_SCAN		0xD7
+#define E_INFO_PHY_DRIVER	0xD8
+
+#define MAX_RETRIES		3
+#define MAX_FW_UPDATE_RETRIES	30
+
+#define ELAN_FW_PAGESIZE	132
+#define ELAN_FW_FILENAME	"elants_i2c.bin"
+
+/* calibration timeout definition */
+#define ELAN_CALI_TIMEOUT_MSEC	10000
+
+enum elants_state {
+	ELAN_STATE_NORMAL,
+	ELAN_WAIT_QUEUE_HEADER,
+	ELAN_WAIT_RECALIBRATION,
+};
+
+enum elants_iap_mode {
+	ELAN_IAP_OPERATIONAL,
+	ELAN_IAP_RECOVERY,
+};
+
+/* struct elants_data - represents state of Elan touchscreen device */
+struct elants_data {
+	struct i2c_client *client;
+	struct input_dev *input;
+
+	u16 fw_version;
+	u8 test_version;
+	u8 solution_version;
+	u8 bc_version;
+	u8 iap_version;
+	u16 hw_version;
+	unsigned int x_res;	/* resolution in units/mm */
+	unsigned int y_res;
+	unsigned int x_max;
+	unsigned int y_max;
+
+	enum elants_state state;
+	enum elants_iap_mode iap_mode;
+
+	/* Guards against concurrent access to the device via sysfs */
+	struct mutex sysfs_mutex;
+
+	u8 cmd_resp[HEADER_SIZE];
+	struct completion cmd_done;
+
+	u8 buf[MAX_PACKET_SIZE];
+
+	bool wake_irq_enabled;
+};
+
+static int elants_i2c_send(struct i2c_client *client,
+			   const void *data, size_t size)
+{
+	int ret;
+
+	ret = i2c_master_send(client, data, size);
+	if (ret == size)
+		return 0;
+
+	if (ret >= 0)
+		ret = -EIO;
+
+	dev_err(&client->dev, "%s failed (%*ph): %d\n",
+		__func__, (int)size, data, ret);
+
+	return ret;
+}
+
+static int elants_i2c_read(struct i2c_client *client, void *data, size_t size)
+{
+	int ret;
+
+	ret = i2c_master_recv(client, data, size);
+	if (ret == size)
+		return 0;
+
+	if (ret >= 0)
+		ret = -EIO;
+
+	dev_err(&client->dev, "%s failed: %d\n", __func__, ret);
+
+	return ret;
+}
+
+static int elants_i2c_execute_command(struct i2c_client *client,
+				      const u8 *cmd, size_t cmd_size,
+				      u8 *resp, size_t resp_size)
+{
+	struct i2c_msg msgs[2];
+	int ret;
+	u8 expected_response;
+
+	switch (cmd[0]) {
+	case CMD_HEADER_READ:
+		expected_response = CMD_HEADER_RESP;
+		break;
+
+	case CMD_HEADER_6B_READ:
+		expected_response = CMD_HEADER_6B_RESP;
+		break;
+
+	default:
+		dev_err(&client->dev, "%s: invalid command %*ph\n",
+			__func__, (int)cmd_size, cmd);
+		return -EINVAL;
+	}
+
+	msgs[0].addr = client->addr;
+	msgs[0].flags = client->flags & I2C_M_TEN;
+	msgs[0].len = cmd_size;
+	msgs[0].buf = (u8 *)cmd;
+
+	msgs[1].addr = client->addr;
+	msgs[1].flags = client->flags & I2C_M_TEN;
+	msgs[1].flags |= I2C_M_RD;
+	msgs[1].len = resp_size;
+	msgs[1].buf = resp;
+
+	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+	if (ret < 0)
+		return ret;
+
+	if (ret != ARRAY_SIZE(msgs) || resp[FW_HDR_TYPE] != expected_response)
+		return -EIO;
+
+	return 0;
+}
+
+static int elants_i2c_calibrate(struct elants_data *ts)
+{
+	struct i2c_client *client = ts->client;
+	int ret, error;
+	static const u8 w_flashkey[] = { 0x54, 0xC0, 0xE1, 0x5A };
+	static const u8 rek[] = { 0x54, 0x29, 0x00, 0x01 };
+	static const u8 rek_resp[] = { CMD_HEADER_REK, 0x66, 0x66, 0x66 };
+
+	disable_irq(client->irq);
+
+	ts->state = ELAN_WAIT_RECALIBRATION;
+	reinit_completion(&ts->cmd_done);
+
+	elants_i2c_send(client, w_flashkey, sizeof(w_flashkey));
+	elants_i2c_send(client, rek, sizeof(rek));
+
+	enable_irq(client->irq);
+
+	ret = wait_for_completion_interruptible_timeout(&ts->cmd_done,
+				msecs_to_jiffies(ELAN_CALI_TIMEOUT_MSEC));
+
+	ts->state = ELAN_STATE_NORMAL;
+
+	if (ret <= 0) {
+		error = ret < 0 ? ret : -ETIMEDOUT;
+		dev_err(&client->dev,
+			"error while waiting for calibration to complete: %d\n",
+			error);
+		return error;
+	}
+
+	if (memcmp(rek_resp, ts->cmd_resp, sizeof(rek_resp))) {
+		dev_err(&client->dev,
+			"unexpected calibration response: %*ph\n",
+			(int)sizeof(ts->cmd_resp), ts->cmd_resp);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int elants_i2c_sw_reset(struct i2c_client *client)
+{
+	const u8 soft_rst_cmd[] = { 0x77, 0x77, 0x77, 0x77 };
+	int error;
+
+	error = elants_i2c_send(client, soft_rst_cmd,
+				sizeof(soft_rst_cmd));
+	if (error) {
+		dev_err(&client->dev, "software reset failed: %d\n", error);
+		return error;
+	}
+
+	/*
+	 * We should wait at least 10 msec (but no more than 40) before
+	 * sending fastboot or IAP command to the device.
+	 */
+	msleep(30);
+
+	return 0;
+}
+
+static u16 elants_i2c_parse_version(u8 *buf)
+{
+	return get_unaligned_be32(buf) >> 4;
+}
+
+static int elants_i2c_query_fw_id(struct elants_data *ts)
+{
+	struct i2c_client *client = ts->client;
+	int error, retry_cnt;
+	const u8 cmd[] = { CMD_HEADER_READ, E_ELAN_INFO_FW_ID, 0x00, 0x01 };
+	u8 resp[HEADER_SIZE];
+
+	for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
+		error = elants_i2c_execute_command(client, cmd, sizeof(cmd),
+						   resp, sizeof(resp));
+		if (!error) {
+			ts->hw_version = elants_i2c_parse_version(resp);
+			if (ts->hw_version != 0xffff)
+				return 0;
+		}
+
+		dev_dbg(&client->dev, "read fw id error=%d, buf=%*phC\n",
+			error, (int)sizeof(resp), resp);
+	}
+
+	dev_err(&client->dev,
+		"Failed to read fw id or fw id is invalid\n");
+
+	return -EINVAL;
+}
+
+static int elants_i2c_query_fw_version(struct elants_data *ts)
+{
+	struct i2c_client *client = ts->client;
+	int error, retry_cnt;
+	const u8 cmd[] = { CMD_HEADER_READ, E_ELAN_INFO_FW_VER, 0x00, 0x01 };
+	u8 resp[HEADER_SIZE];
+
+	for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
+		error = elants_i2c_execute_command(client, cmd, sizeof(cmd),
+						   resp, sizeof(resp));
+		if (!error) {
+			ts->fw_version = elants_i2c_parse_version(resp);
+			if (ts->fw_version != 0x0000 &&
+			    ts->fw_version != 0xffff)
+				return 0;
+		}
+
+		dev_dbg(&client->dev, "read fw version error=%d, buf=%*phC\n",
+			error, (int)sizeof(resp), resp);
+	}
+
+	dev_err(&client->dev,
+		"Failed to read fw version or fw version is invalid\n");
+
+	return -EINVAL;
+}
+
+static int elants_i2c_query_test_version(struct elants_data *ts)
+{
+	struct i2c_client *client = ts->client;
+	int error, retry_cnt;
+	u16 version;
+	const u8 cmd[] = { CMD_HEADER_READ, E_ELAN_INFO_TEST_VER, 0x00, 0x01 };
+	u8 resp[HEADER_SIZE];
+
+	for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
+		error = elants_i2c_execute_command(client, cmd, sizeof(cmd),
+						   resp, sizeof(resp));
+		if (!error) {
+			version = elants_i2c_parse_version(resp);
+			ts->test_version = version >> 8;
+			ts->solution_version = version & 0xff;
+
+			return 0;
+		}
+
+		dev_dbg(&client->dev,
+			"read test version error rc=%d, buf=%*phC\n",
+			error, (int)sizeof(resp), resp);
+	}
+
+	dev_err(&client->dev, "Failed to read test version\n");
+
+	return -EINVAL;
+}
+
+static int elants_i2c_query_bc_version(struct elants_data *ts)
+{
+	struct i2c_client *client = ts->client;
+	const u8 cmd[] = { CMD_HEADER_READ, E_ELAN_INFO_BC_VER, 0x00, 0x01 };
+	u8 resp[HEADER_SIZE];
+	u16 version;
+	int error;
+
+	error = elants_i2c_execute_command(client, cmd, sizeof(cmd),
+					   resp, sizeof(resp));
+	if (error) {
+		dev_err(&client->dev,
+			"read BC version error=%d, buf=%*phC\n",
+			error, (int)sizeof(resp), resp);
+		return error;
+	}
+
+	version = elants_i2c_parse_version(resp);
+	ts->bc_version = version >> 8;
+	ts->iap_version = version & 0xff;
+
+	return 0;
+}
+
+static int elants_i2c_query_ts_info(struct elants_data *ts)
+{
+	struct i2c_client *client = ts->client;
+	int error;
+	u8 resp[17];
+	u16 phy_x, phy_y, rows, cols, osr;
+	const u8 get_resolution_cmd[] = {
+		CMD_HEADER_6B_READ, 0x00, 0x00, 0x00, 0x00, 0x00
+	};
+	const u8 get_osr_cmd[] = {
+		CMD_HEADER_READ, E_INFO_OSR, 0x00, 0x01
+	};
+	const u8 get_physical_scan_cmd[] = {
+		CMD_HEADER_READ, E_INFO_PHY_SCAN, 0x00, 0x01
+	};
+	const u8 get_physical_drive_cmd[] = {
+		CMD_HEADER_READ, E_INFO_PHY_DRIVER, 0x00, 0x01
+	};
+
+	/* Get trace number */
+	error = elants_i2c_execute_command(client,
+					   get_resolution_cmd,
+					   sizeof(get_resolution_cmd),
+					   resp, sizeof(resp));
+	if (error) {
+		dev_err(&client->dev, "get resolution command failed: %d\n",
+			error);
+		return error;
+	}
+
+	rows = resp[2] + resp[6] + resp[10];
+	cols = resp[3] + resp[7] + resp[11];
+
+	/* Process mm_to_pixel information */
+	error = elants_i2c_execute_command(client,
+					   get_osr_cmd, sizeof(get_osr_cmd),
+					   resp, sizeof(resp));
+	if (error) {
+		dev_err(&client->dev, "get osr command failed: %d\n",
+			error);
+		return error;
+	}
+
+	osr = resp[3];
+
+	error = elants_i2c_execute_command(client,
+					   get_physical_scan_cmd,
+					   sizeof(get_physical_scan_cmd),
+					   resp, sizeof(resp));
+	if (error) {
+		dev_err(&client->dev, "get physical scan command failed: %d\n",
+			error);
+		return error;
+	}
+
+	phy_x = get_unaligned_be16(&resp[2]);
+
+	error = elants_i2c_execute_command(client,
+					   get_physical_drive_cmd,
+					   sizeof(get_physical_drive_cmd),
+					   resp, sizeof(resp));
+	if (error) {
+		dev_err(&client->dev, "get physical drive command failed: %d\n",
+			error);
+		return error;
+	}
+
+	phy_y = get_unaligned_be16(&resp[2]);
+
+	dev_dbg(&client->dev, "phy_x=%d, phy_y=%d\n", phy_x, phy_y);
+
+	if (rows == 0 || cols == 0 || osr == 0) {
+		dev_warn(&client->dev,
+			 "invalid trace number data: %d, %d, %d\n",
+			 rows, cols, osr);
+	} else {
+		/* translate trace number to TS resolution */
+		ts->x_max = ELAN_TS_RESOLUTION(rows, osr);
+		ts->x_res = DIV_ROUND_CLOSEST(ts->x_max, phy_x);
+		ts->y_max = ELAN_TS_RESOLUTION(cols, osr);
+		ts->y_res = DIV_ROUND_CLOSEST(ts->y_max, phy_y);
+	}
+
+	return 0;
+}
+
+static int elants_i2c_fastboot(struct i2c_client *client)
+{
+	const u8 boot_cmd[] = { 0x4D, 0x61, 0x69, 0x6E };
+	int error;
+
+	error = elants_i2c_send(client, boot_cmd, sizeof(boot_cmd));
+	if (error) {
+		dev_err(&client->dev, "boot failed: %d\n", error);
+		return error;
+	}
+
+	dev_dbg(&client->dev, "boot success -- 0x%x\n", client->addr);
+	return 0;
+}
+
+static int elants_i2c_initialize(struct elants_data *ts)
+{
+	struct i2c_client *client = ts->client;
+	int error, retry_cnt;
+	const u8 hello_packet[] = { 0x55, 0x55, 0x55, 0x55 };
+	const u8 recov_packet[] = { 0x55, 0x55, 0x80, 0x80 };
+	u8 buf[HEADER_SIZE];
+
+	for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
+		error = elants_i2c_sw_reset(client);
+		if (error) {
+			/* Continue initializing if it's the last try */
+			if (retry_cnt < MAX_RETRIES - 1)
+				continue;
+		}
+
+		error = elants_i2c_fastboot(client);
+		if (error) {
+			/* Continue initializing if it's the last try */
+			if (retry_cnt < MAX_RETRIES - 1)
+				continue;
+		}
+
+		/* Wait for Hello packet */
+		msleep(BOOT_TIME_DELAY_MS);
+
+		error = elants_i2c_read(client, buf, sizeof(buf));
+		if (error) {
+			dev_err(&client->dev,
+				"failed to read 'hello' packet: %d\n", error);
+		} else if (!memcmp(buf, hello_packet, sizeof(hello_packet))) {
+			ts->iap_mode = ELAN_IAP_OPERATIONAL;
+			break;
+		} else if (!memcmp(buf, recov_packet, sizeof(recov_packet))) {
+			/*
+			 * Setting error code will mark device
+			 * in recovery mode below.
+			 */
+			error = -EIO;
+			break;
+		} else {
+			error = -EINVAL;
+			dev_err(&client->dev,
+				"invalid 'hello' packet: %*ph\n",
+				(int)sizeof(buf), buf);
+		}
+	}
+
+	if (!error)
+		error = elants_i2c_query_fw_id(ts);
+	if (!error)
+		error = elants_i2c_query_fw_version(ts);
+
+	if (error) {
+		ts->iap_mode = ELAN_IAP_RECOVERY;
+	} else {
+		elants_i2c_query_test_version(ts);
+		elants_i2c_query_bc_version(ts);
+		elants_i2c_query_ts_info(ts);
+	}
+
+	return 0;
+}
+
+/*
+ * Firmware update interface.
+ */
+
+static int elants_i2c_fw_write_page(struct i2c_client *client,
+				    const void *page)
+{
+	const u8 ack_ok[] = { 0xaa, 0xaa };
+	u8 buf[2];
+	int retry;
+	int error;
+
+	for (retry = 0; retry < MAX_FW_UPDATE_RETRIES; retry++) {
+		error = elants_i2c_send(client, page, ELAN_FW_PAGESIZE);
+		if (error) {
+			dev_err(&client->dev,
+				"IAP Write Page failed: %d\n", error);
+			continue;
+		}
+
+		error = elants_i2c_read(client, buf, 2);
+		if (error) {
+			dev_err(&client->dev,
+				"IAP Ack read failed: %d\n", error);
+			return error;
+		}
+
+		if (!memcmp(buf, ack_ok, sizeof(ack_ok)))
+			return 0;
+
+		error = -EIO;
+		dev_err(&client->dev,
+			"IAP Get Ack Error [%02x:%02x]\n",
+			buf[0], buf[1]);
+	}
+
+	return error;
+}
+
+static int elants_i2c_do_update_firmware(struct i2c_client *client,
+					 const struct firmware *fw,
+					 bool force)
+{
+	const u8 enter_iap[] = { 0x45, 0x49, 0x41, 0x50 };
+	const u8 enter_iap2[] = { 0x54, 0x00, 0x12, 0x34 };
+	const u8 iap_ack[] = { 0x55, 0xaa, 0x33, 0xcc };
+	u8 buf[HEADER_SIZE];
+	u16 send_id;
+	int page, n_fw_pages;
+	int error;
+
+	/* Recovery mode detection! */
+	if (force) {
+		dev_dbg(&client->dev, "Recovery mode procedure\n");
+		error = elants_i2c_send(client, enter_iap2, sizeof(enter_iap2));
+	} else {
+		/* Start IAP Procedure */
+		dev_dbg(&client->dev, "Normal IAP procedure\n");
+		elants_i2c_sw_reset(client);
+
+		error = elants_i2c_send(client, enter_iap, sizeof(enter_iap));
+	}
+
+	if (error) {
+		dev_err(&client->dev, "failed to enter IAP mode: %d\n", error);
+		return error;
+	}
+
+	msleep(20);
+
+	/* check IAP state */
+	error = elants_i2c_read(client, buf, 4);
+	if (error) {
+		dev_err(&client->dev,
+			"failed to read IAP acknowledgement: %d\n",
+			error);
+		return error;
+	}
+
+	if (memcmp(buf, iap_ack, sizeof(iap_ack))) {
+		dev_err(&client->dev,
+			"failed to enter IAP: %*ph (expected %*ph)\n",
+			(int)sizeof(buf), buf, (int)sizeof(iap_ack), iap_ack);
+		return -EIO;
+	}
+
+	dev_info(&client->dev, "successfully entered IAP mode");
+
+	send_id = client->addr;
+	error = elants_i2c_send(client, &send_id, 1);
+	if (error) {
+		dev_err(&client->dev, "sending dummy byte failed: %d\n",
+			error);
+		return error;
+	}
+
+	/* Clear the last page of Master */
+	error = elants_i2c_send(client, fw->data, ELAN_FW_PAGESIZE);
+	if (error) {
+		dev_err(&client->dev, "clearing of the last page failed: %d\n",
+			error);
+		return error;
+	}
+
+	error = elants_i2c_read(client, buf, 2);
+	if (error) {
+		dev_err(&client->dev,
+			"failed to read ACK for clearing the last page: %d\n",
+			error);
+		return error;
+	}
+
+	n_fw_pages = fw->size / ELAN_FW_PAGESIZE;
+	dev_dbg(&client->dev, "IAP Pages = %d\n", n_fw_pages);
+
+	for (page = 0; page < n_fw_pages; page++) {
+		error = elants_i2c_fw_write_page(client,
+					fw->data + page * ELAN_FW_PAGESIZE);
+		if (error) {
+			dev_err(&client->dev,
+				"failed to write FW page %d: %d\n",
+				page, error);
+			return error;
+		}
+	}
+
+	/* Old iap needs to wait 200ms for WDT and rest is for hello packets */
+	msleep(300);
+
+	dev_info(&client->dev, "firmware update completed\n");
+	return 0;
+}
+
+static int elants_i2c_fw_update(struct elants_data *ts)
+{
+	struct i2c_client *client = ts->client;
+	const struct firmware *fw;
+	int error;
+
+	error = request_firmware(&fw, ELAN_FW_FILENAME, &client->dev);
+	if (error) {
+		dev_err(&client->dev, "failed to request firmware %s: %d\n",
+			ELAN_FW_FILENAME, error);
+		return error;
+	}
+
+	if (fw->size % ELAN_FW_PAGESIZE) {
+		dev_err(&client->dev, "invalid firmware length: %zu\n",
+			fw->size);
+		error = -EINVAL;
+		goto out;
+	}
+
+	disable_irq(client->irq);
+
+	error = elants_i2c_do_update_firmware(client, fw,
+					ts->iap_mode == ELAN_IAP_RECOVERY);
+	if (error) {
+		dev_err(&client->dev, "firmware update failed: %d\n", error);
+		ts->iap_mode = ELAN_IAP_RECOVERY;
+		goto out_enable_irq;
+	}
+
+	error = elants_i2c_initialize(ts);
+	if (error) {
+		dev_err(&client->dev,
+			"failed to initialize device after firmware update: %d\n",
+			error);
+		ts->iap_mode = ELAN_IAP_RECOVERY;
+		goto out_enable_irq;
+	}
+
+	ts->iap_mode = ELAN_IAP_OPERATIONAL;
+
+out_enable_irq:
+	ts->state = ELAN_STATE_NORMAL;
+	enable_irq(client->irq);
+	msleep(100);
+
+	if (!error)
+		elants_i2c_calibrate(ts);
+out:
+	release_firmware(fw);
+	return error;
+}
+
+/*
+ * Event reporting.
+ */
+
+static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf)
+{
+	struct input_dev *input = ts->input;
+	unsigned int n_fingers;
+	u16 finger_state;
+	int i;
+
+	n_fingers = buf[FW_POS_STATE + 1] & 0x0f;
+	finger_state = ((buf[FW_POS_STATE + 1] & 0x30) << 4) |
+			buf[FW_POS_STATE];
+
+	dev_dbg(&ts->client->dev,
+		"n_fingers: %u, state: %04x\n",  n_fingers, finger_state);
+
+	for (i = 0; i < MAX_CONTACT_NUM && n_fingers; i++) {
+		if (finger_state & 1) {
+			unsigned int x, y, p, w;
+			u8 *pos;
+
+			pos = &buf[FW_POS_XY + i * 3];
+			x = (((u16)pos[0] & 0xf0) << 4) | pos[1];
+			y = (((u16)pos[0] & 0x0f) << 8) | pos[2];
+			p = buf[FW_POS_PRESSURE + i];
+			w = buf[FW_POS_WIDTH + i];
+
+			dev_dbg(&ts->client->dev, "i=%d x=%d y=%d p=%d w=%d\n",
+				i, x, y, p, w);
+
+			input_mt_slot(input, i);
+			input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
+			input_event(input, EV_ABS, ABS_MT_POSITION_X, x);
+			input_event(input, EV_ABS, ABS_MT_POSITION_Y, y);
+			input_event(input, EV_ABS, ABS_MT_PRESSURE, p);
+			input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, w);
+
+			n_fingers--;
+		}
+
+		finger_state >>= 1;
+	}
+
+	input_mt_sync_frame(input);
+	input_sync(input);
+}
+
+static u8 elants_i2c_calculate_checksum(u8 *buf)
+{
+	u8 checksum = 0;
+	u8 i;
+
+	for (i = 0; i < FW_POS_CHECKSUM; i++)
+		checksum += buf[i];
+
+	return checksum;
+}
+
+static void elants_i2c_event(struct elants_data *ts, u8 *buf)
+{
+	u8 checksum = elants_i2c_calculate_checksum(buf);
+
+	if (unlikely(buf[FW_POS_CHECKSUM] != checksum))
+		dev_warn(&ts->client->dev,
+			 "%s: invalid checksum for packet %02x: %02x vs. %02x\n",
+			 __func__, buf[FW_POS_HEADER],
+			 checksum, buf[FW_POS_CHECKSUM]);
+	else if (unlikely(buf[FW_POS_HEADER] != HEADER_REPORT_10_FINGER))
+		dev_warn(&ts->client->dev,
+			 "%s: unknown packet type: %02x\n",
+			 __func__, buf[FW_POS_HEADER]);
+	else
+		elants_i2c_mt_event(ts, buf);
+}
+
+static irqreturn_t elants_i2c_irq(int irq, void *_dev)
+{
+	const u8 wait_packet[] = { 0x64, 0x64, 0x64, 0x64 };
+	struct elants_data *ts = _dev;
+	struct i2c_client *client = ts->client;
+	int report_count, report_len;
+	int i;
+	int len;
+
+	len = i2c_master_recv(client, ts->buf, sizeof(ts->buf));
+	if (len < 0) {
+		dev_err(&client->dev, "%s: failed to read data: %d\n",
+			__func__, len);
+		goto out;
+	}
+
+	dev_dbg(&client->dev, "%s: packet %*ph\n",
+		__func__, HEADER_SIZE, ts->buf);
+
+	switch (ts->state) {
+	case ELAN_WAIT_RECALIBRATION:
+		if (ts->buf[FW_HDR_TYPE] == CMD_HEADER_REK) {
+			memcpy(ts->cmd_resp, ts->buf, sizeof(ts->cmd_resp));
+			complete(&ts->cmd_done);
+			ts->state = ELAN_STATE_NORMAL;
+		}
+		break;
+
+	case ELAN_WAIT_QUEUE_HEADER:
+		if (ts->buf[FW_HDR_TYPE] != QUEUE_HEADER_NORMAL)
+			break;
+
+		ts->state = ELAN_STATE_NORMAL;
+		/* fall through */
+
+	case ELAN_STATE_NORMAL:
+
+		switch (ts->buf[FW_HDR_TYPE]) {
+		case CMD_HEADER_HELLO:
+		case CMD_HEADER_RESP:
+		case CMD_HEADER_REK:
+			break;
+
+		case QUEUE_HEADER_WAIT:
+			if (memcmp(ts->buf, wait_packet, sizeof(wait_packet))) {
+				dev_err(&client->dev,
+					"invalid wait packet %*ph\n",
+					HEADER_SIZE, ts->buf);
+			} else {
+				ts->state = ELAN_WAIT_QUEUE_HEADER;
+				udelay(30);
+			}
+			break;
+
+		case QUEUE_HEADER_SINGLE:
+			elants_i2c_event(ts, &ts->buf[HEADER_SIZE]);
+			break;
+
+		case QUEUE_HEADER_NORMAL:
+			report_count = ts->buf[FW_HDR_COUNT];
+			if (report_count > 3) {
+				dev_err(&client->dev,
+					"too large report count: %*ph\n",
+					HEADER_SIZE, ts->buf);
+				break;
+			}
+
+			report_len = ts->buf[FW_HDR_LENGTH] / report_count;
+			if (report_len != PACKET_SIZE) {
+				dev_err(&client->dev,
+					"mismatching report length: %*ph\n",
+					HEADER_SIZE, ts->buf);
+				break;
+			}
+
+			for (i = 0; i < report_count; i++) {
+				u8 *buf = ts->buf + HEADER_SIZE +
+							i * PACKET_SIZE;
+				elants_i2c_event(ts, buf);
+			}
+			break;
+
+		default:
+			dev_err(&client->dev, "unknown packet %*ph\n",
+				HEADER_SIZE, ts->buf);
+			break;
+		}
+		break;
+	}
+
+out:
+	return IRQ_HANDLED;
+}
+
+/*
+ * sysfs interface
+ */
+static ssize_t calibrate_store(struct device *dev,
+			       struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct elants_data *ts = i2c_get_clientdata(client);
+	int error;
+
+	error = mutex_lock_interruptible(&ts->sysfs_mutex);
+	if (error)
+		return error;
+
+	error = elants_i2c_calibrate(ts);
+
+	mutex_unlock(&ts->sysfs_mutex);
+	return error ?: count;
+}
+
+static ssize_t write_update_fw(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct elants_data *ts = i2c_get_clientdata(client);
+	int error;
+
+	error = mutex_lock_interruptible(&ts->sysfs_mutex);
+	if (error)
+		return error;
+
+	error = elants_i2c_fw_update(ts);
+	dev_dbg(dev, "firmware update result: %d\n", error);
+
+	mutex_unlock(&ts->sysfs_mutex);
+	return error ?: count;
+}
+
+static ssize_t show_iap_mode(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct elants_data *ts = i2c_get_clientdata(client);
+
+	return sprintf(buf, "%s\n",
+		       ts->iap_mode == ELAN_IAP_OPERATIONAL ?
+				"Normal" : "Recovery");
+}
+
+static DEVICE_ATTR(calibrate, S_IWUSR, NULL, calibrate_store);
+static DEVICE_ATTR(iap_mode, S_IRUGO, show_iap_mode, NULL);
+static DEVICE_ATTR(update_fw, S_IWUSR, NULL, write_update_fw);
+
+struct elants_version_attribute {
+	struct device_attribute dattr;
+	size_t field_offset;
+	size_t field_size;
+};
+
+#define __ELANTS_FIELD_SIZE(_field)					\
+	sizeof(((struct elants_data *)NULL)->_field)
+#define __ELANTS_VERIFY_SIZE(_field)					\
+	(BUILD_BUG_ON_ZERO(__ELANTS_FIELD_SIZE(_field) > 2) +		\
+	 __ELANTS_FIELD_SIZE(_field))
+#define ELANTS_VERSION_ATTR(_field)					\
+	struct elants_version_attribute elants_ver_attr_##_field = {	\
+		.dattr = __ATTR(_field, S_IRUGO,			\
+				elants_version_attribute_show, NULL),	\
+		.field_offset = offsetof(struct elants_data, _field),	\
+		.field_size = __ELANTS_VERIFY_SIZE(_field),		\
+	}
+
+static ssize_t elants_version_attribute_show(struct device *dev,
+					     struct device_attribute *dattr,
+					     char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct elants_data *ts = i2c_get_clientdata(client);
+	struct elants_version_attribute *attr =
+		container_of(dattr, struct elants_version_attribute, dattr);
+	u8 *field = (u8 *)((char *)ts + attr->field_offset);
+	unsigned int fmt_size;
+	unsigned int val;
+
+	if (attr->field_size == 1) {
+		val = *field;
+		fmt_size = 2; /* 2 HEX digits */
+	} else {
+		val = *(u16 *)field;
+		fmt_size = 4; /* 4 HEX digits */
+	}
+
+	return sprintf(buf, "%0*x\n", fmt_size, val);
+}
+
+static ELANTS_VERSION_ATTR(fw_version);
+static ELANTS_VERSION_ATTR(hw_version);
+static ELANTS_VERSION_ATTR(test_version);
+static ELANTS_VERSION_ATTR(solution_version);
+static ELANTS_VERSION_ATTR(bc_version);
+static ELANTS_VERSION_ATTR(iap_version);
+
+static struct attribute *elants_attributes[] = {
+	&dev_attr_calibrate.attr,
+	&dev_attr_update_fw.attr,
+	&dev_attr_iap_mode.attr,
+
+	&elants_ver_attr_fw_version.dattr.attr,
+	&elants_ver_attr_hw_version.dattr.attr,
+	&elants_ver_attr_test_version.dattr.attr,
+	&elants_ver_attr_solution_version.dattr.attr,
+	&elants_ver_attr_bc_version.dattr.attr,
+	&elants_ver_attr_iap_version.dattr.attr,
+	NULL
+};
+
+static struct attribute_group elants_attribute_group = {
+	.attrs = elants_attributes,
+};
+
+static void elants_i2c_remove_sysfs_group(void *_data)
+{
+	struct elants_data *ts = _data;
+
+	sysfs_remove_group(&ts->client->dev.kobj, &elants_attribute_group);
+}
+
+static int elants_i2c_probe(struct i2c_client *client,
+			    const struct i2c_device_id *id)
+{
+	union i2c_smbus_data dummy;
+	struct elants_data *ts;
+	unsigned long irqflags;
+	int error;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+		dev_err(&client->dev,
+			"%s: i2c check functionality error\n", DEVICE_NAME);
+		return -ENXIO;
+	}
+
+	/* Make sure there is something at this address */
+	if (i2c_smbus_xfer(client->adapter, client->addr, 0,
+			I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &dummy) < 0) {
+		dev_err(&client->dev, "nothing at this address\n");
+		return -ENXIO;
+	}
+
+	ts = devm_kzalloc(&client->dev, sizeof(struct elants_data), GFP_KERNEL);
+	if (!ts)
+		return -ENOMEM;
+
+	mutex_init(&ts->sysfs_mutex);
+	init_completion(&ts->cmd_done);
+
+	ts->client = client;
+	i2c_set_clientdata(client, ts);
+
+	error = elants_i2c_initialize(ts);
+	if (error) {
+		dev_err(&client->dev, "failed to initialize: %d\n", error);
+		return error;
+	}
+
+	ts->input = devm_input_allocate_device(&client->dev);
+	if (!ts->input) {
+		dev_err(&client->dev, "Failed to allocate input device\n");
+		return -ENOMEM;
+	}
+
+	ts->input->name = "Elan Touchscreen";
+	ts->input->id.bustype = BUS_I2C;
+
+	__set_bit(BTN_TOUCH, ts->input->keybit);
+	__set_bit(EV_ABS, ts->input->evbit);
+	__set_bit(EV_KEY, ts->input->evbit);
+
+	/* Single touch input params setup */
+	input_set_abs_params(ts->input, ABS_X, 0, ts->x_max, 0, 0);
+	input_set_abs_params(ts->input, ABS_Y, 0, ts->y_max, 0, 0);
+	input_set_abs_params(ts->input, ABS_PRESSURE, 0, 255, 0, 0);
+	input_abs_set_res(ts->input, ABS_X, ts->x_res);
+	input_abs_set_res(ts->input, ABS_Y, ts->y_res);
+
+	/* Multitouch input params setup */
+	error = input_mt_init_slots(ts->input, MAX_CONTACT_NUM,
+				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
+	if (error) {
+		dev_err(&client->dev,
+			"failed to initialize MT slots: %d\n", error);
+		return error;
+	}
+
+	input_set_abs_params(ts->input, ABS_MT_POSITION_X, 0, ts->x_max, 0, 0);
+	input_set_abs_params(ts->input, ABS_MT_POSITION_Y, 0, ts->y_max, 0, 0);
+	input_set_abs_params(ts->input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
+	input_set_abs_params(ts->input, ABS_MT_PRESSURE, 0, 255, 0, 0);
+	input_abs_set_res(ts->input, ABS_MT_POSITION_X, ts->x_res);
+	input_abs_set_res(ts->input, ABS_MT_POSITION_Y, ts->y_res);
+
+	input_set_drvdata(ts->input, ts);
+
+	error = input_register_device(ts->input);
+	if (error) {
+		dev_err(&client->dev,
+			"unable to register input device: %d\n", error);
+		return error;
+	}
+
+	/*
+	 * Systems using device tree should set up interrupt via DTS,
+	 * the rest will use the default falling edge interrupts.
+	 */
+	irqflags = client->dev.of_node ? 0 : IRQF_TRIGGER_FALLING;
+
+	error = devm_request_threaded_irq(&client->dev, client->irq,
+					  NULL, elants_i2c_irq,
+					  irqflags | IRQF_ONESHOT,
+					  client->name, ts);
+	if (error) {
+		dev_err(&client->dev, "Failed to register interrupt\n");
+		return error;
+	}
+
+	/*
+	 * Systems using device tree should set up wakeup via DTS,
+	 * the rest will configure device as wakeup source by default.
+	 */
+	if (!client->dev.of_node)
+		device_init_wakeup(&client->dev, true);
+
+	error = sysfs_create_group(&client->dev.kobj, &elants_attribute_group);
+	if (error) {
+		dev_err(&client->dev, "failed to create sysfs attributes: %d\n",
+			error);
+		return error;
+	}
+
+	error = devm_add_action(&client->dev,
+				elants_i2c_remove_sysfs_group, ts);
+	if (error) {
+		elants_i2c_remove_sysfs_group(ts);
+		dev_err(&client->dev,
+			"Failed to add sysfs cleanup action: %d\n",
+			error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int __maybe_unused elants_i2c_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct elants_data *ts = i2c_get_clientdata(client);
+	const u8 set_sleep_cmd[] = { 0x54, 0x50, 0x00, 0x01 };
+	int retry_cnt;
+	int error;
+
+	/* Command not support in IAP recovery mode */
+	if (ts->iap_mode != ELAN_IAP_OPERATIONAL)
+		return -EBUSY;
+
+	disable_irq(client->irq);
+
+	for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
+		error = elants_i2c_send(client, set_sleep_cmd,
+					sizeof(set_sleep_cmd));
+		if (!error)
+			break;
+
+		dev_err(&client->dev, "suspend command failed: %d\n", error);
+	}
+
+	if (device_may_wakeup(dev))
+		ts->wake_irq_enabled = (enable_irq_wake(client->irq) == 0);
+
+	return 0;
+}
+
+static int __maybe_unused elants_i2c_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct elants_data *ts = i2c_get_clientdata(client);
+	const u8 set_active_cmd[] = { 0x54, 0x58, 0x00, 0x01 };
+	int retry_cnt;
+	int error;
+
+	if (device_may_wakeup(dev) && ts->wake_irq_enabled)
+		disable_irq_wake(client->irq);
+
+	for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
+		error = elants_i2c_send(client, set_active_cmd,
+					sizeof(set_active_cmd));
+		if (!error)
+			break;
+
+		dev_err(&client->dev, "resume command failed: %d\n", error);
+	}
+
+	ts->state = ELAN_STATE_NORMAL;
+	enable_irq(client->irq);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(elants_i2c_pm_ops,
+			 elants_i2c_suspend, elants_i2c_resume);
+
+static const struct i2c_device_id elants_i2c_id[] = {
+	{ DEVICE_NAME, 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, elants_i2c_id);
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id elants_acpi_id[] = {
+	{ "ELAN0001", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, elants_acpi_id);
+#endif
+
+#ifdef CONFIG_OF
+static const struct of_device_id elants_of_match[] = {
+	{ .compatible = "elan,ekth3500" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, elants_of_match);
+#endif
+
+static struct i2c_driver elants_i2c_driver = {
+	.probe = elants_i2c_probe,
+	.id_table = elants_i2c_id,
+	.driver = {
+		.name = DEVICE_NAME,
+		.owner = THIS_MODULE,
+		.pm = &elants_i2c_pm_ops,
+		.acpi_match_table = ACPI_PTR(elants_acpi_id),
+		.of_match_table = of_match_ptr(elants_of_match),
+	},
+};
+module_i2c_driver(elants_i2c_driver);
+
+MODULE_AUTHOR("Scott Liu <[e-mail]>");
+MODULE_DESCRIPTION("Elan I2c Touchscreen driver");
+MODULE_VERSION(DRV_VERSION);
+MODULE_LICENSE("GPL");