Input: add a driver for wdt87xx touchscreen controller
authorHungNien Chen <hn.chen@weidahitech.com>
Mon, 15 Jun 2015 15:57:08 +0000 (18:57 +0300)
committerDmitry Torokhov <dmitry.torokhov@gmail.com>
Wed, 24 Jun 2015 21:55:54 +0000 (14:55 -0700)
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>
drivers/input/touchscreen/Kconfig
drivers/input/touchscreen/Makefile
drivers/input/touchscreen/wdt87xx_i2c.c [new file with mode: 0644]

index a398d636ca39c2c303bd2e10e31ca10bd0091581..aa2b5f21b89b44d4114eb5307cc7be681fd3adb5 100644 (file)
@@ -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
index 44deea743d022539a08a44d49c7611f7bfbd4908..fa3d33bac7fc0755e9fbeec0e5983ad4d3b6f8ca 100644 (file)
@@ -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 (file)
index 0000000..c073ea9
--- /dev/null
@@ -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");