Input: add a driver for wdt87xx touchscreen controller

This is a driver for Weida HiTech WDT87xx series touchscreen controller.

Signed-off-by: HungNien Chen <hn.chen@weidahitech.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

3 files changed, 1153 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index a398d636ca39..aa2b5f21b89b 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -658,6 +658,18 @@ config TOUCHSCREEN_PIXCIR
 	  To compile this driver as a module, choose M here: the
 	  module will be called pixcir_i2c_ts.
 
+config TOUCHSCREEN_WDT87XX_I2C
+	tristate "Weida HiTech I2C touchscreen"
+	depends on I2C
+	help
+	  Say Y here if you have a Weida WDT87XX 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 wdt87xx_i2c.
+
 config TOUCHSCREEN_WM831X
 	tristate "Support for WM831x touchscreen controllers"
 	depends on MFD_WM831X
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 44deea743d02..fa3d33bac7fc 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -72,6 +72,7 @@ obj-$(CONFIG_TOUCHSCREEN_TSC2007)	+= tsc2007.o
 obj-$(CONFIG_TOUCHSCREEN_UCB1400)	+= ucb1400_ts.o
 obj-$(CONFIG_TOUCHSCREEN_WACOM_W8001)	+= wacom_w8001.o
 obj-$(CONFIG_TOUCHSCREEN_WACOM_I2C)	+= wacom_i2c.o
+obj-$(CONFIG_TOUCHSCREEN_WDT87XX_I2C)	+= wdt87xx_i2c.o
 obj-$(CONFIG_TOUCHSCREEN_WM831X)	+= wm831x-ts.o
 obj-$(CONFIG_TOUCHSCREEN_WM97XX)	+= wm97xx-ts.o
 wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9705)	+= wm9705.o
diff --git a/drivers/input/touchscreen/wdt87xx_i2c.c b/drivers/input/touchscreen/wdt87xx_i2c.c
new file mode 100644
index 000000000000..c073ea9345e2
--- /dev/null
+++ b/drivers/input/touchscreen/wdt87xx_i2c.c
@@ -0,0 +1,1140 @@
+/*
+ * Weida HiTech WDT87xx TouchScreen I2C driver
+ *
+ * Copyright (c) 2015  Weida Hi-Tech Co., Ltd.
+ * HN Chen <hn.chen@weidahitech.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ */
+
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/firmware.h>
+#include <linux/input/mt.h>
+#include <linux/acpi.h>
+#include <asm/unaligned.h>
+
+#define WDT87XX_NAME		"wdt87xx_i2c"
+#define WDT87XX_DRV_VER		"0.9.5"
+#define WDT87XX_FW_NAME		"wdt87xx_fw.bin"
+#define WDT87XX_CFG_NAME	"wdt87xx_cfg.bin"
+
+#define MODE_ACTIVE			0x01
+#define MODE_READY			0x02
+#define MODE_IDLE			0x03
+#define MODE_SLEEP			0x04
+#define MODE_STOP			0xFF
+
+#define WDT_MAX_FINGER			10
+#define WDT_RAW_BUF_COUNT		54
+#define WDT_V1_RAW_BUF_COUNT		74
+#define WDT_FIRMWARE_ID			0xa9e368f5
+
+#define PG_SIZE				0x1000
+#define MAX_RETRIES			3
+
+#define MAX_UNIT_AXIS			0x7FFF
+
+#define PKT_READ_SIZE			72
+#define PKT_WRITE_SIZE			80
+
+/* the finger definition of the report event */
+#define FINGER_EV_OFFSET_ID		0
+#define FINGER_EV_OFFSET_X		1
+#define FINGER_EV_OFFSET_Y		3
+#define FINGER_EV_SIZE			5
+
+#define FINGER_EV_V1_OFFSET_ID		0
+#define FINGER_EV_V1_OFFSET_W		1
+#define FINGER_EV_V1_OFFSET_P		2
+#define FINGER_EV_V1_OFFSET_X		3
+#define FINGER_EV_V1_OFFSET_Y		5
+#define FINGER_EV_V1_SIZE		7
+
+/* The definition of a report packet */
+#define TOUCH_PK_OFFSET_REPORT_ID	0
+#define TOUCH_PK_OFFSET_EVENT		1
+#define TOUCH_PK_OFFSET_SCAN_TIME	51
+#define TOUCH_PK_OFFSET_FNGR_NUM	53
+
+#define TOUCH_PK_V1_OFFSET_REPORT_ID	0
+#define TOUCH_PK_V1_OFFSET_EVENT	1
+#define TOUCH_PK_V1_OFFSET_SCAN_TIME	71
+#define TOUCH_PK_V1_OFFSET_FNGR_NUM	73
+
+/* The definition of the controller parameters */
+#define CTL_PARAM_OFFSET_FW_ID		0
+#define CTL_PARAM_OFFSET_PLAT_ID	2
+#define CTL_PARAM_OFFSET_XMLS_ID1	4
+#define CTL_PARAM_OFFSET_XMLS_ID2	6
+#define CTL_PARAM_OFFSET_PHY_CH_X	8
+#define CTL_PARAM_OFFSET_PHY_CH_Y	10
+#define CTL_PARAM_OFFSET_PHY_X0		12
+#define CTL_PARAM_OFFSET_PHY_X1		14
+#define CTL_PARAM_OFFSET_PHY_Y0		16
+#define CTL_PARAM_OFFSET_PHY_Y1		18
+#define CTL_PARAM_OFFSET_PHY_W		22
+#define CTL_PARAM_OFFSET_PHY_H		24
+
+/* Communication commands */
+#define PACKET_SIZE			56
+#define VND_REQ_READ			0x06
+#define VND_READ_DATA			0x07
+#define VND_REQ_WRITE			0x08
+
+#define VND_CMD_START			0x00
+#define VND_CMD_STOP			0x01
+#define VND_CMD_RESET			0x09
+
+#define VND_CMD_ERASE			0x1A
+
+#define VND_GET_CHECKSUM		0x66
+
+#define VND_SET_DATA			0x83
+#define VND_SET_COMMAND_DATA		0x84
+#define VND_SET_CHECKSUM_CALC		0x86
+#define VND_SET_CHECKSUM_LENGTH		0x87
+
+#define VND_CMD_SFLCK			0xFC
+#define VND_CMD_SFUNL			0xFD
+
+#define CMD_SFLCK_KEY			0xC39B
+#define CMD_SFUNL_KEY			0x95DA
+
+#define STRIDX_PLATFORM_ID		0x80
+#define STRIDX_PARAMETERS		0x81
+
+#define CMD_BUF_SIZE			8
+#define PKT_BUF_SIZE			64
+
+/* The definition of the command packet */
+#define CMD_REPORT_ID_OFFSET		0x0
+#define CMD_TYPE_OFFSET			0x1
+#define CMD_INDEX_OFFSET		0x2
+#define CMD_KEY_OFFSET			0x3
+#define CMD_LENGTH_OFFSET		0x4
+#define CMD_DATA_OFFSET			0x8
+
+/* The definition of firmware chunk tags */
+#define FOURCC_ID_RIFF			0x46464952
+#define FOURCC_ID_WHIF			0x46494857
+#define FOURCC_ID_FRMT			0x544D5246
+#define FOURCC_ID_FRWR			0x52575246
+#define FOURCC_ID_CNFG			0x47464E43
+
+#define CHUNK_ID_FRMT			FOURCC_ID_FRMT
+#define CHUNK_ID_FRWR			FOURCC_ID_FRWR
+#define CHUNK_ID_CNFG			FOURCC_ID_CNFG
+
+#define FW_FOURCC1_OFFSET		0
+#define FW_SIZE_OFFSET			4
+#define FW_FOURCC2_OFFSET		8
+#define FW_PAYLOAD_OFFSET		40
+
+#define FW_CHUNK_ID_OFFSET		0
+#define FW_CHUNK_SIZE_OFFSET		4
+#define FW_CHUNK_TGT_START_OFFSET	8
+#define FW_CHUNK_PAYLOAD_LEN_OFFSET	12
+#define FW_CHUNK_SRC_START_OFFSET	16
+#define FW_CHUNK_VERSION_OFFSET		20
+#define FW_CHUNK_ATTR_OFFSET		24
+#define FW_CHUNK_PAYLOAD_OFFSET		32
+
+/* Controller requires minimum 300us between commands */
+#define WDT_COMMAND_DELAY_MS		2
+#define WDT_FLASH_WRITE_DELAY_MS	4
+
+struct wdt87xx_sys_param {
+	u16	fw_id;
+	u16	plat_id;
+	u16	xmls_id1;
+	u16	xmls_id2;
+	u16	phy_ch_x;
+	u16	phy_ch_y;
+	u16	phy_w;
+	u16	phy_h;
+	u32	max_x;
+	u32	max_y;
+};
+
+struct wdt87xx_data {
+	struct i2c_client		*client;
+	struct input_dev		*input;
+	/* Mutex for fw update to prevent concurrent access */
+	struct mutex			fw_mutex;
+	struct wdt87xx_sys_param	param;
+	u8				phys[32];
+};
+
+static int wdt87xx_i2c_xfer(struct i2c_client *client,
+			    void *txdata, size_t txlen,
+			    void *rxdata, size_t rxlen)
+{
+	struct i2c_msg msgs[] = {
+		{
+			.addr	= client->addr,
+			.flags	= 0,
+			.len	= txlen,
+			.buf	= txdata,
+		},
+		{
+			.addr	= client->addr,
+			.flags	= I2C_M_RD,
+			.len	= rxlen,
+			.buf	= rxdata,
+		},
+	};
+	int error;
+	int ret;
+
+	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+	if (ret != ARRAY_SIZE(msgs)) {
+		error = ret < 0 ? ret : -EIO;
+		dev_err(&client->dev, "%s: i2c transfer failed: %d\n",
+			__func__, error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int wdt87xx_get_string(struct i2c_client *client, u8 str_idx,
+			      u8 *buf, size_t len)
+{
+	u8 tx_buf[] = { 0x22, 0x00, 0x13, 0x0E, str_idx, 0x23, 0x00 };
+	u8 rx_buf[PKT_WRITE_SIZE];
+	size_t rx_len = len + 2;
+	int error;
+
+	if (rx_len > sizeof(rx_buf))
+		return -EINVAL;
+
+	error = wdt87xx_i2c_xfer(client, tx_buf, sizeof(tx_buf),
+				 rx_buf, rx_len);
+	if (error) {
+		dev_err(&client->dev, "get string failed: %d\n", error);
+		return error;
+	}
+
+	if (rx_buf[1] != 0x03) {
+		dev_err(&client->dev, "unexpected response to get string: %d\n",
+			rx_buf[1]);
+		return -EINVAL;
+	}
+
+	rx_len = min_t(size_t, len, rx_buf[0]);
+	memcpy(buf, &rx_buf[2], rx_len);
+
+	mdelay(WDT_COMMAND_DELAY_MS);
+
+	return 0;
+}
+
+static int wdt87xx_get_feature(struct i2c_client *client,
+			       u8 *buf, size_t buf_size)
+{
+	u8 tx_buf[8];
+	u8 rx_buf[PKT_WRITE_SIZE];
+	size_t tx_len = 0;
+	size_t rx_len = buf_size + 2;
+	int error;
+
+	if (rx_len > sizeof(rx_buf))
+		return -EINVAL;
+
+	/* Get feature command packet */
+	tx_buf[tx_len++] = 0x22;
+	tx_buf[tx_len++] = 0x00;
+	if (buf[CMD_REPORT_ID_OFFSET] > 0xF) {
+		tx_buf[tx_len++] = 0x30;
+		tx_buf[tx_len++] = 0x02;
+		tx_buf[tx_len++] = buf[CMD_REPORT_ID_OFFSET];
+	} else {
+		tx_buf[tx_len++] = 0x30 | buf[CMD_REPORT_ID_OFFSET];
+		tx_buf[tx_len++] = 0x02;
+	}
+	tx_buf[tx_len++] = 0x23;
+	tx_buf[tx_len++] = 0x00;
+
+	error = wdt87xx_i2c_xfer(client, tx_buf, tx_len, rx_buf, rx_len);
+	if (error) {
+		dev_err(&client->dev, "get feature failed: %d\n", error);
+		return error;
+	}
+
+	rx_len = min_t(size_t, buf_size, get_unaligned_le16(rx_buf));
+	memcpy(buf, &rx_buf[2], rx_len);
+
+	mdelay(WDT_COMMAND_DELAY_MS);
+
+	return 0;
+}
+
+static int wdt87xx_set_feature(struct i2c_client *client,
+			       const u8 *buf, size_t buf_size)
+{
+	u8 tx_buf[PKT_WRITE_SIZE];
+	int tx_len = 0;
+	int error;
+
+	/* Set feature command packet */
+	tx_buf[tx_len++] = 0x22;
+	tx_buf[tx_len++] = 0x00;
+	if (buf[CMD_REPORT_ID_OFFSET] > 0xF) {
+		tx_buf[tx_len++] = 0x30;
+		tx_buf[tx_len++] = 0x03;
+		tx_buf[tx_len++] = buf[CMD_REPORT_ID_OFFSET];
+	} else {
+		tx_buf[tx_len++] = 0x30 | buf[CMD_REPORT_ID_OFFSET];
+		tx_buf[tx_len++] = 0x03;
+	}
+	tx_buf[tx_len++] = 0x23;
+	tx_buf[tx_len++] = 0x00;
+	tx_buf[tx_len++] = (buf_size & 0xFF);
+	tx_buf[tx_len++] = ((buf_size & 0xFF00) >> 8);
+
+	if (tx_len + buf_size > sizeof(tx_buf))
+		return -EINVAL;
+
+	memcpy(&tx_buf[tx_len], buf, buf_size);
+	tx_len += buf_size;
+
+	error = i2c_master_send(client, tx_buf, tx_len);
+	if (error < 0) {
+		dev_err(&client->dev, "set feature failed: %d\n", error);
+		return error;
+	}
+
+	mdelay(WDT_COMMAND_DELAY_MS);
+
+	return 0;
+}
+
+static int wdt87xx_send_command(struct i2c_client *client, int cmd, int value)
+{
+	u8 cmd_buf[CMD_BUF_SIZE];
+
+	/* Set the command packet */
+	cmd_buf[CMD_REPORT_ID_OFFSET] = VND_REQ_WRITE;
+	cmd_buf[CMD_TYPE_OFFSET] = VND_SET_COMMAND_DATA;
+	put_unaligned_le16((u16)cmd, &cmd_buf[CMD_INDEX_OFFSET]);
+
+	switch (cmd) {
+	case VND_CMD_START:
+	case VND_CMD_STOP:
+	case VND_CMD_RESET:
+		/* Mode selector */
+		put_unaligned_le32((value & 0xFF), &cmd_buf[CMD_LENGTH_OFFSET]);
+		break;
+
+	case VND_CMD_SFLCK:
+		put_unaligned_le16(CMD_SFLCK_KEY, &cmd_buf[CMD_KEY_OFFSET]);
+		break;
+
+	case VND_CMD_SFUNL:
+		put_unaligned_le16(CMD_SFUNL_KEY, &cmd_buf[CMD_KEY_OFFSET]);
+		break;
+
+	case VND_CMD_ERASE:
+	case VND_SET_CHECKSUM_CALC:
+	case VND_SET_CHECKSUM_LENGTH:
+		put_unaligned_le32(value, &cmd_buf[CMD_KEY_OFFSET]);
+		break;
+
+	default:
+		cmd_buf[CMD_REPORT_ID_OFFSET] = 0;
+		dev_err(&client->dev, "Invalid command: %d\n", cmd);
+		return -EINVAL;
+	}
+
+	return wdt87xx_set_feature(client, cmd_buf, sizeof(cmd_buf));
+}
+
+static int wdt87xx_sw_reset(struct i2c_client *client)
+{
+	int error;
+
+	dev_dbg(&client->dev, "resetting device now\n");
+
+	error = wdt87xx_send_command(client, VND_CMD_RESET, 0);
+	if (error) {
+		dev_err(&client->dev, "reset failed\n");
+		return error;
+	}
+
+	/* Wait the device to be ready */
+	msleep(200);
+
+	return 0;
+}
+
+static const void *wdt87xx_get_fw_chunk(const struct firmware *fw, u32 id)
+{
+	size_t pos = FW_PAYLOAD_OFFSET;
+	u32 chunk_id, chunk_size;
+
+	while (pos < fw->size) {
+		chunk_id = get_unaligned_le32(fw->data +
+					      pos + FW_CHUNK_ID_OFFSET);
+		if (chunk_id == id)
+			return fw->data + pos;
+
+		chunk_size = get_unaligned_le32(fw->data +
+						pos + FW_CHUNK_SIZE_OFFSET);
+		pos += chunk_size + 2 * sizeof(u32); /* chunk ID + size */
+	}
+
+	return NULL;
+}
+
+static int wdt87xx_get_sysparam(struct i2c_client *client,
+				struct wdt87xx_sys_param *param)
+{
+	u8 buf[PKT_READ_SIZE];
+	int error;
+
+	error = wdt87xx_get_string(client, STRIDX_PARAMETERS, buf, 32);
+	if (error) {
+		dev_err(&client->dev, "failed to get parameters\n");
+		return error;
+	}
+
+	param->xmls_id1 = get_unaligned_le16(buf + CTL_PARAM_OFFSET_XMLS_ID1);
+	param->xmls_id2 = get_unaligned_le16(buf + CTL_PARAM_OFFSET_XMLS_ID2);
+	param->phy_ch_x = get_unaligned_le16(buf + CTL_PARAM_OFFSET_PHY_CH_X);
+	param->phy_ch_y = get_unaligned_le16(buf + CTL_PARAM_OFFSET_PHY_CH_Y);
+	param->phy_w = get_unaligned_le16(buf + CTL_PARAM_OFFSET_PHY_W) / 10;
+	param->phy_h = get_unaligned_le16(buf + CTL_PARAM_OFFSET_PHY_H) / 10;
+
+	param->max_x = MAX_UNIT_AXIS;
+	param->max_y = DIV_ROUND_CLOSEST(MAX_UNIT_AXIS * param->phy_h,
+					 param->phy_w);
+
+	error = wdt87xx_get_string(client, STRIDX_PLATFORM_ID, buf, 8);
+	if (error) {
+		dev_err(&client->dev, "failed to get platform id\n");
+		return error;
+	}
+
+	param->plat_id = buf[1];
+
+	buf[0] = 0xf2;
+	error = wdt87xx_get_feature(client, buf, 16);
+	if (error) {
+		dev_err(&client->dev, "failed to get firmware id\n");
+		return error;
+	}
+
+	if (buf[0] != 0xf2) {
+		dev_err(&client->dev, "wrong id of fw response: 0x%x\n",
+			buf[0]);
+		return -EINVAL;
+	}
+
+	param->fw_id = get_unaligned_le16(&buf[1]);
+
+	dev_info(&client->dev,
+		 "fw_id: 0x%x, plat_id: 0x%x\nxml_id1: %04x, xml_id2: %04x\n",
+		 param->fw_id, param->plat_id,
+		 param->xmls_id1, param->xmls_id2);
+
+	return 0;
+}
+
+static int wdt87xx_validate_firmware(struct wdt87xx_data *wdt,
+				     const struct firmware *fw)
+{
+	const void *fw_chunk;
+	u32 data1, data2;
+	u32 size;
+	u8 fw_chip_id;
+	u8 chip_id;
+
+	data1 = get_unaligned_le32(fw->data + FW_FOURCC1_OFFSET);
+	data2 = get_unaligned_le32(fw->data + FW_FOURCC2_OFFSET);
+	if (data1 != FOURCC_ID_RIFF || data2 != FOURCC_ID_WHIF) {
+		dev_err(&wdt->client->dev, "check fw tag failed\n");
+		return -EINVAL;
+	}
+
+	size = get_unaligned_le32(fw->data + FW_SIZE_OFFSET);
+	if (size != fw->size) {
+		dev_err(&wdt->client->dev,
+			"fw size mismatch: expected %d, actual %zd\n",
+			size, fw->size);
+		return -EINVAL;
+	}
+
+	/*
+	 * Get the chip_id from the firmware. Make sure that it is the
+	 * right controller to do the firmware and config update.
+	 */
+	fw_chunk = wdt87xx_get_fw_chunk(fw, CHUNK_ID_FRWR);
+	if (!fw_chunk) {
+		dev_err(&wdt->client->dev,
+			"unable to locate firmware chunk\n");
+		return -EINVAL;
+	}
+
+	fw_chip_id = (get_unaligned_le32(fw_chunk +
+					 FW_CHUNK_VERSION_OFFSET) >> 12) & 0xF;
+	chip_id = (wdt->param.fw_id >> 12) & 0xF;
+
+	if (fw_chip_id != chip_id) {
+		dev_err(&wdt->client->dev,
+			"fw version mismatch: fw %d vs. chip %d\n",
+			fw_chip_id, chip_id);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int wdt87xx_validate_fw_chunk(const void *data, int id)
+{
+	if (id == CHUNK_ID_FRWR) {
+		u32 fw_id;
+
+		fw_id = get_unaligned_le32(data + FW_CHUNK_PAYLOAD_OFFSET);
+		if (fw_id != WDT_FIRMWARE_ID)
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int wdt87xx_write_data(struct i2c_client *client, const char *data,
+			      u32 address, int length)
+{
+	u16 packet_size;
+	int count = 0;
+	int error;
+	u8 pkt_buf[PKT_BUF_SIZE];
+
+	/* Address and length should be 4 bytes aligned */
+	if ((address & 0x3) != 0 || (length & 0x3) != 0) {
+		dev_err(&client->dev,
+			"addr & len must be 4 bytes aligned %x, %x\n",
+			address, length);
+		return -EINVAL;
+	}
+
+	while (length) {
+		packet_size = min(length, PACKET_SIZE);
+
+		pkt_buf[CMD_REPORT_ID_OFFSET] = VND_REQ_WRITE;
+		pkt_buf[CMD_TYPE_OFFSET] = VND_SET_DATA;
+		put_unaligned_le16(packet_size, &pkt_buf[CMD_INDEX_OFFSET]);
+		put_unaligned_le32(address, &pkt_buf[CMD_LENGTH_OFFSET]);
+		memcpy(&pkt_buf[CMD_DATA_OFFSET], data, packet_size);
+
+		error = wdt87xx_set_feature(client, pkt_buf, sizeof(pkt_buf));
+		if (error)
+			return error;
+
+		length -= packet_size;
+		data += packet_size;
+		address += packet_size;
+
+		/* Wait for the controller to finish the write */
+		mdelay(WDT_FLASH_WRITE_DELAY_MS);
+
+		if ((++count % 32) == 0) {
+			/* Delay for fw to clear watch dog */
+			msleep(20);
+		}
+	}
+
+	return 0;
+}
+
+static u16 misr(u16 cur_value, u8 new_value)
+{
+	u32 a, b;
+	u32 bit0;
+	u32 y;
+
+	a = cur_value;
+	b = new_value;
+	bit0 = a ^ (b & 1);
+	bit0 ^= a >> 1;
+	bit0 ^= a >> 2;
+	bit0 ^= a >> 4;
+	bit0 ^= a >> 5;
+	bit0 ^= a >> 7;
+	bit0 ^= a >> 11;
+	bit0 ^= a >> 15;
+	y = (a << 1) ^ b;
+	y = (y & ~1) | (bit0 & 1);
+
+	return (u16)y;
+}
+
+static u16 wdt87xx_calculate_checksum(const u8 *data, size_t length)
+{
+	u16 checksum = 0;
+	size_t i;
+
+	for (i = 0; i < length; i++)
+		checksum = misr(checksum, data[i]);
+
+	return checksum;
+}
+
+static int wdt87xx_get_checksum(struct i2c_client *client, u16 *checksum,
+				u32 address, int length)
+{
+	int error;
+	int time_delay;
+	u8 pkt_buf[PKT_BUF_SIZE];
+	u8 cmd_buf[CMD_BUF_SIZE];
+
+	error = wdt87xx_send_command(client, VND_SET_CHECKSUM_LENGTH, length);
+	if (error) {
+		dev_err(&client->dev, "failed to set checksum length\n");
+		return error;
+	}
+
+	error = wdt87xx_send_command(client, VND_SET_CHECKSUM_CALC, address);
+	if (error) {
+		dev_err(&client->dev, "failed to set checksum address\n");
+		return error;
+	}
+
+	/* Wait the operation to complete */
+	time_delay = DIV_ROUND_UP(length, 1024);
+	msleep(time_delay * 30);
+
+	memset(cmd_buf, 0, sizeof(cmd_buf));
+	cmd_buf[CMD_REPORT_ID_OFFSET] = VND_REQ_READ;
+	cmd_buf[CMD_TYPE_OFFSET] = VND_GET_CHECKSUM;
+	error = wdt87xx_set_feature(client, cmd_buf, sizeof(cmd_buf));
+	if (error) {
+		dev_err(&client->dev, "failed to request checksum\n");
+		return error;
+	}
+
+	memset(pkt_buf, 0, sizeof(pkt_buf));
+	pkt_buf[CMD_REPORT_ID_OFFSET] = VND_READ_DATA;
+	error = wdt87xx_get_feature(client, pkt_buf, sizeof(pkt_buf));
+	if (error) {
+		dev_err(&client->dev, "failed to read checksum\n");
+		return error;
+	}
+
+	*checksum = get_unaligned_le16(&pkt_buf[CMD_DATA_OFFSET]);
+	return 0;
+}
+
+static int wdt87xx_write_firmware(struct i2c_client *client, const void *chunk)
+{
+	u32 start_addr = get_unaligned_le32(chunk + FW_CHUNK_TGT_START_OFFSET);
+	u32 size = get_unaligned_le32(chunk + FW_CHUNK_PAYLOAD_LEN_OFFSET);
+	const void *data = chunk + FW_CHUNK_PAYLOAD_OFFSET;
+	int error;
+	int err1;
+	int page_size;
+	int retry = 0;
+	u16 device_checksum, firmware_checksum;
+
+	dev_dbg(&client->dev, "start 4k page program\n");
+
+	error = wdt87xx_send_command(client, VND_CMD_STOP, MODE_STOP);
+	if (error) {
+		dev_err(&client->dev, "stop report mode failed\n");
+		return error;
+	}
+
+	error = wdt87xx_send_command(client, VND_CMD_SFUNL, 0);
+	if (error) {
+		dev_err(&client->dev, "unlock failed\n");
+		goto out_enable_reporting;
+	}
+
+	mdelay(10);
+
+	while (size) {
+		dev_dbg(&client->dev, "%s: %x, %x\n", __func__,
+			start_addr, size);
+
+		page_size = min_t(u32, size, PG_SIZE);
+		size -= page_size;
+
+		for (retry = 0; retry < MAX_RETRIES; retry++) {
+			error = wdt87xx_send_command(client, VND_CMD_ERASE,
+						     start_addr);
+			if (error) {
+				dev_err(&client->dev,
+					"erase failed at %#08x\n", start_addr);
+				break;
+			}
+
+			msleep(50);
+
+			error = wdt87xx_write_data(client, data, start_addr,
+						   page_size);
+			if (error) {
+				dev_err(&client->dev,
+					"write failed at %#08x (%d bytes)\n",
+					start_addr, page_size);
+				break;
+			}
+
+			error = wdt87xx_get_checksum(client, &device_checksum,
+						     start_addr, page_size);
+			if (error) {
+				dev_err(&client->dev,
+					"failed to retrieve checksum for %#08x (len: %d)\n",
+					start_addr, page_size);
+				break;
+			}
+
+			firmware_checksum =
+				wdt87xx_calculate_checksum(data, page_size);
+
+			if (device_checksum == firmware_checksum)
+				break;
+
+			dev_err(&client->dev,
+				"checksum fail: %d vs %d, retry %d\n",
+				device_checksum, firmware_checksum, retry);
+		}
+
+		if (retry == MAX_RETRIES) {
+			dev_err(&client->dev, "page write failed\n");
+			error = -EIO;
+			goto out_lock_device;
+		}
+
+		start_addr = start_addr + page_size;
+		data = data + page_size;
+	}
+
+out_lock_device:
+	err1 = wdt87xx_send_command(client, VND_CMD_SFLCK, 0);
+	if (err1)
+		dev_err(&client->dev, "lock failed\n");
+
+	mdelay(10);
+
+out_enable_reporting:
+	err1 = wdt87xx_send_command(client, VND_CMD_START, 0);
+	if (err1)
+		dev_err(&client->dev, "start to report failed\n");
+
+	return error ? error : err1;
+}
+
+static int wdt87xx_load_chunk(struct i2c_client *client,
+			      const struct firmware *fw, u32 ck_id)
+{
+	const void *chunk;
+	int error;
+
+	chunk = wdt87xx_get_fw_chunk(fw, ck_id);
+	if (!chunk) {
+		dev_err(&client->dev, "unable to locate chunk (type %d)\n",
+			ck_id);
+		return -EINVAL;
+	}
+
+	error = wdt87xx_validate_fw_chunk(chunk, ck_id);
+	if (error) {
+		dev_err(&client->dev, "invalid chunk (type %d): %d\n",
+			ck_id, error);
+		return error;
+	}
+
+	error = wdt87xx_write_firmware(client, chunk);
+	if (error) {
+		dev_err(&client->dev,
+			"failed to write fw chunk (type %d): %d\n",
+			ck_id, error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int wdt87xx_do_update_firmware(struct i2c_client *client,
+				      const struct firmware *fw,
+				      unsigned int chunk_id)
+{
+	struct wdt87xx_data *wdt = i2c_get_clientdata(client);
+	int error;
+
+	error = wdt87xx_validate_firmware(wdt, fw);
+	if (error)
+		return error;
+
+	error = mutex_lock_interruptible(&wdt->fw_mutex);
+	if (error)
+		return error;
+
+	disable_irq(client->irq);
+
+	error = wdt87xx_load_chunk(client, fw, chunk_id);
+	if (error) {
+		dev_err(&client->dev,
+			"firmware load failed (type: %d): %d\n",
+			chunk_id, error);
+		goto out;
+	}
+
+	error = wdt87xx_sw_reset(client);
+	if (error) {
+		dev_err(&client->dev, "soft reset failed: %d\n", error);
+		goto out;
+	}
+
+	/* Refresh the parameters */
+	error = wdt87xx_get_sysparam(client, &wdt->param);
+	if (error)
+		dev_err(&client->dev,
+			"failed to refresh system paramaters: %d\n", error);
+out:
+	enable_irq(client->irq);
+	mutex_unlock(&wdt->fw_mutex);
+
+	return error ? error : 0;
+}
+
+static int wdt87xx_update_firmware(struct device *dev,
+				   const char *fw_name, unsigned int chunk_id)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	const struct firmware *fw;
+	int error;
+
+	error = request_firmware(&fw, fw_name, dev);
+	if (error) {
+		dev_err(&client->dev, "unable to retrieve firmware %s: %d\n",
+			fw_name, error);
+		return error;
+	}
+
+	error = wdt87xx_do_update_firmware(client, fw, chunk_id);
+
+	release_firmware(fw);
+
+	return error ? error : 0;
+}
+
+static ssize_t config_csum_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct wdt87xx_data *wdt = i2c_get_clientdata(client);
+	u32 cfg_csum;
+
+	cfg_csum = wdt->param.xmls_id1;
+	cfg_csum = (cfg_csum << 16) | wdt->param.xmls_id2;
+
+	return scnprintf(buf, PAGE_SIZE, "%x\n", cfg_csum);
+}
+
+static ssize_t fw_version_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct wdt87xx_data *wdt = i2c_get_clientdata(client);
+
+	return scnprintf(buf, PAGE_SIZE, "%x\n", wdt->param.fw_id);
+}
+
+static ssize_t plat_id_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct wdt87xx_data *wdt = i2c_get_clientdata(client);
+
+	return scnprintf(buf, PAGE_SIZE, "%x\n", wdt->param.plat_id);
+}
+
+static ssize_t update_config_store(struct device *dev,
+				   struct device_attribute *attr,
+				   const char *buf, size_t count)
+{
+	int error;
+
+	error = wdt87xx_update_firmware(dev, WDT87XX_CFG_NAME, CHUNK_ID_CNFG);
+
+	return error ? error : count;
+}
+
+static ssize_t update_fw_store(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	int error;
+
+	error = wdt87xx_update_firmware(dev, WDT87XX_FW_NAME, CHUNK_ID_FRWR);
+
+	return error ? error : count;
+}
+
+static DEVICE_ATTR_RO(config_csum);
+static DEVICE_ATTR_RO(fw_version);
+static DEVICE_ATTR_RO(plat_id);
+static DEVICE_ATTR_WO(update_config);
+static DEVICE_ATTR_WO(update_fw);
+
+static struct attribute *wdt87xx_attrs[] = {
+	&dev_attr_config_csum.attr,
+	&dev_attr_fw_version.attr,
+	&dev_attr_plat_id.attr,
+	&dev_attr_update_config.attr,
+	&dev_attr_update_fw.attr,
+	NULL
+};
+
+static const struct attribute_group wdt87xx_attr_group = {
+	.attrs = wdt87xx_attrs,
+};
+
+static void wdt87xx_report_contact(struct input_dev *input,
+				   struct wdt87xx_sys_param *param,
+				   u8 *buf)
+{
+	int finger_id;
+	u32 x, y;
+	u8 w, p;
+
+	finger_id = (buf[FINGER_EV_V1_OFFSET_ID] >> 3) - 1;
+	if (finger_id < 0)
+		return;
+
+	/* Check if this is an active contact */
+	if (!(buf[FINGER_EV_V1_OFFSET_ID] & 0x1))
+		return;
+
+	w = buf[FINGER_EV_V1_OFFSET_W];
+	p = buf[FINGER_EV_V1_OFFSET_P];
+
+	x = get_unaligned_le16(buf + FINGER_EV_V1_OFFSET_X);
+
+	y = get_unaligned_le16(buf + FINGER_EV_V1_OFFSET_Y);
+	y = DIV_ROUND_CLOSEST(y * param->phy_h, param->phy_w);
+
+	/* Refuse incorrect coordinates */
+	if (x > param->max_x || y > param->max_y)
+		return;
+
+	dev_dbg(input->dev.parent, "tip on (%d), x(%d), y(%d)\n",
+		finger_id, x, y);
+
+	input_mt_slot(input, finger_id);
+	input_mt_report_slot_state(input, MT_TOOL_FINGER, 1);
+	input_report_abs(input, ABS_MT_TOUCH_MAJOR, w);
+	input_report_abs(input, ABS_MT_PRESSURE, p);
+	input_report_abs(input, ABS_MT_POSITION_X, x);
+	input_report_abs(input, ABS_MT_POSITION_Y, y);
+}
+
+static irqreturn_t wdt87xx_ts_interrupt(int irq, void *dev_id)
+{
+	struct wdt87xx_data *wdt = dev_id;
+	struct i2c_client *client = wdt->client;
+	int i, fingers;
+	int error;
+	u8 raw_buf[WDT_V1_RAW_BUF_COUNT] = {0};
+
+	error = i2c_master_recv(client, raw_buf, WDT_V1_RAW_BUF_COUNT);
+	if (error < 0) {
+		dev_err(&client->dev, "read v1 raw data failed: %d\n", error);
+		goto irq_exit;
+	}
+
+	fingers = raw_buf[TOUCH_PK_V1_OFFSET_FNGR_NUM];
+	if (!fingers)
+		goto irq_exit;
+
+	for (i = 0; i < WDT_MAX_FINGER; i++)
+		wdt87xx_report_contact(wdt->input,
+				       &wdt->param,
+				       &raw_buf[TOUCH_PK_V1_OFFSET_EVENT +
+						i * FINGER_EV_V1_SIZE]);
+
+	input_mt_sync_frame(wdt->input);
+	input_sync(wdt->input);
+
+irq_exit:
+	return IRQ_HANDLED;
+}
+
+static int wdt87xx_ts_create_input_device(struct wdt87xx_data *wdt)
+{
+	struct device *dev = &wdt->client->dev;
+	struct input_dev *input;
+	unsigned int res = DIV_ROUND_CLOSEST(MAX_UNIT_AXIS, wdt->param.phy_w);
+	int error;
+
+	input = devm_input_allocate_device(dev);
+	if (!input) {
+		dev_err(dev, "failed to allocate input device\n");
+		return -ENOMEM;
+	}
+	wdt->input = input;
+
+	input->name = "WDT87xx Touchscreen";
+	input->id.bustype = BUS_I2C;
+	input->phys = wdt->phys;
+
+	input_set_abs_params(input, ABS_MT_POSITION_X, 0,
+			     wdt->param.max_x, 0, 0);
+	input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
+			     wdt->param.max_y, 0, 0);
+	input_abs_set_res(input, ABS_MT_POSITION_X, res);
+	input_abs_set_res(input, ABS_MT_POSITION_Y, res);
+
+	input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 0, 0xFF, 0, 0);
+	input_set_abs_params(input, ABS_MT_PRESSURE, 0, 0xFF, 0, 0);
+
+	input_mt_init_slots(input, WDT_MAX_FINGER,
+			    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
+
+	error = input_register_device(input);
+	if (error) {
+		dev_err(dev, "failed to register input device: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int wdt87xx_ts_probe(struct i2c_client *client,
+			    const struct i2c_device_id *id)
+{
+	struct wdt87xx_data *wdt;
+	int error;
+
+	dev_dbg(&client->dev, "adapter=%d, client irq: %d\n",
+		client->adapter->nr, client->irq);
+
+	/* Check if the I2C function is ok in this adaptor */
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+		return -ENXIO;
+
+	wdt = devm_kzalloc(&client->dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	wdt->client = client;
+	mutex_init(&wdt->fw_mutex);
+	i2c_set_clientdata(client, wdt);
+
+	snprintf(wdt->phys, sizeof(wdt->phys), "i2c-%u-%04x/input0",
+		 client->adapter->nr, client->addr);
+
+	error = wdt87xx_get_sysparam(client, &wdt->param);
+	if (error)
+		return error;
+
+	error = wdt87xx_ts_create_input_device(wdt);
+	if (error)
+		return error;
+
+	error = devm_request_threaded_irq(&client->dev, client->irq,
+					  NULL, wdt87xx_ts_interrupt,
+					  IRQF_ONESHOT,
+					  client->name, wdt);
+	if (error) {
+		dev_err(&client->dev, "request irq failed: %d\n", error);
+		return error;
+	}
+
+	error = sysfs_create_group(&client->dev.kobj, &wdt87xx_attr_group);
+	if (error) {
+		dev_err(&client->dev, "create sysfs failed: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int wdt87xx_ts_remove(struct i2c_client *client)
+{
+	sysfs_remove_group(&client->dev.kobj, &wdt87xx_attr_group);
+
+	return 0;
+}
+
+static int __maybe_unused wdt87xx_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int error;
+
+	disable_irq(client->irq);
+
+	error = wdt87xx_send_command(client, VND_CMD_STOP, MODE_IDLE);
+	if (error) {
+		enable_irq(client->irq);
+		dev_err(&client->dev,
+			"failed to stop device when suspending: %d\n",
+			error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int __maybe_unused wdt87xx_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int error;
+
+	/*
+	 * The chip may have been reset while system is resuming,
+	 * give it some time to settle.
+	 */
+	mdelay(100);
+
+	error = wdt87xx_send_command(client, VND_CMD_START, 0);
+	if (error)
+		dev_err(&client->dev,
+			"failed to start device when resuming: %d\n",
+			error);
+
+	enable_irq(client->irq);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(wdt87xx_pm_ops, wdt87xx_suspend, wdt87xx_resume);
+
+static const struct i2c_device_id wdt87xx_dev_id[] = {
+	{ WDT87XX_NAME, 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, wdt87xx_dev_id);
+
+static const struct acpi_device_id wdt87xx_acpi_id[] = {
+	{ "WDHT0001", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, wdt87xx_acpi_id);
+
+static struct i2c_driver wdt87xx_driver = {
+	.probe		= wdt87xx_ts_probe,
+	.remove		= wdt87xx_ts_remove,
+	.id_table	= wdt87xx_dev_id,
+	.driver	= {
+		.name	= WDT87XX_NAME,
+		.pm     = &wdt87xx_pm_ops,
+		.acpi_match_table = ACPI_PTR(wdt87xx_acpi_id),
+	},
+};
+module_i2c_driver(wdt87xx_driver);
+
+MODULE_AUTHOR("HN Chen <hn.chen@weidahitech.com>");
+MODULE_DESCRIPTION("WeidaHiTech WDT87XX Touchscreen driver");
+MODULE_VERSION(WDT87XX_DRV_VER);
+MODULE_LICENSE("GPL");