USB: serial: add Fintek F81532/534 driver
authorJi-Ze Hong (Peter Hong) <hpeter@gmail.com>
Mon, 14 Nov 2016 05:37:59 +0000 (13:37 +0800)
committerJohan Hovold <johan@kernel.org>
Tue, 29 Nov 2016 10:13:16 +0000 (11:13 +0100)
This driver is for Fintek F81532/F81534 USB to Serial Ports IC.

F81532 spec:
https://drive.google.com/file/d/0B8vRwwYO7aMFOTRRMmhWQVNvajQ/view?usp=
sharing

F81534 spec:
https://drive.google.com/file/d/0B8vRwwYO7aMFV29pQWJqbVBNc00/view?usp=
sharing

Features:
1. F81532 is 1-to-2 & F81534 is 1-to-4 serial ports IC
2. Support Baudrate from B50 to B115200.

Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
drivers/usb/serial/Kconfig
drivers/usb/serial/Makefile
drivers/usb/serial/f81534.c [new file with mode: 0644]

index 56ecb8b5115dd66b8d0db52849e9738e127a2afa..d9bc8dafe000c84732e19c4a7530ab150c1f23fc 100644 (file)
@@ -255,6 +255,16 @@ config USB_SERIAL_F81232
          To compile this driver as a module, choose M here: the
          module will be called f81232.
 
+config USB_SERIAL_F8153X
+       tristate "USB Fintek F81532/534 Multi-Ports Serial Driver"
+       help
+         Say Y here if you want to use the Fintek F81532/534 Multi-Ports
+         USB to serial adapter.
+
+         To compile this driver as a module, choose M here: the
+         module will be called f81534.
+
+
 config USB_SERIAL_GARMIN
        tristate "USB Garmin GPS driver"
        help
index 349d9df0895f5afc4139b046383362bc46348739..9e43b7b002eba7dc7c98c81919e0889f4be8b877 100644 (file)
@@ -23,6 +23,7 @@ obj-$(CONFIG_USB_SERIAL_EDGEPORT)             += io_edgeport.o
 obj-$(CONFIG_USB_SERIAL_EDGEPORT_TI)           += io_ti.o
 obj-$(CONFIG_USB_SERIAL_EMPEG)                 += empeg.o
 obj-$(CONFIG_USB_SERIAL_F81232)                        += f81232.o
+obj-$(CONFIG_USB_SERIAL_F8153X)                        += f81534.o
 obj-$(CONFIG_USB_SERIAL_FTDI_SIO)              += ftdi_sio.o
 obj-$(CONFIG_USB_SERIAL_GARMIN)                        += garmin_gps.o
 obj-$(CONFIG_USB_SERIAL_IPAQ)                  += ipaq.o
diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c
new file mode 100644 (file)
index 0000000..8282a6a
--- /dev/null
@@ -0,0 +1,1409 @@
+/*
+ * F81532/F81534 USB to Serial Ports Bridge
+ *
+ * F81532 => 2 Serial Ports
+ * F81534 => 4 Serial Ports
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Copyright (C) 2016 Feature Integration Technology Inc., (Fintek)
+ * Copyright (C) 2016 Tom Tsai (Tom_Tsai@fintek.com.tw)
+ * Copyright (C) 2016 Peter Hong (Peter_Hong@fintek.com.tw)
+ *
+ * The F81532/F81534 had 1 control endpoint for setting, 1 endpoint bulk-out
+ * for all serial port TX and 1 endpoint bulk-in for all serial port read in
+ * (Read Data/MSR/LSR).
+ *
+ * Write URB is fixed with 512bytes, per serial port used 128Bytes.
+ * It can be described by f81534_prepare_write_buffer()
+ *
+ * Read URB is 512Bytes max, per serial port used 128Bytes.
+ * It can be described by f81534_process_read_urb() and maybe received with
+ * 128x1,2,3,4 bytes.
+ *
+ */
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+#include <linux/serial_reg.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+
+/* Serial Port register Address */
+#define F81534_UART_BASE_ADDRESS       0x1200
+#define F81534_UART_OFFSET             0x10
+#define F81534_DIVISOR_LSB_REG         (0x00 + F81534_UART_BASE_ADDRESS)
+#define F81534_DIVISOR_MSB_REG         (0x01 + F81534_UART_BASE_ADDRESS)
+#define F81534_FIFO_CONTROL_REG                (0x02 + F81534_UART_BASE_ADDRESS)
+#define F81534_LINE_CONTROL_REG                (0x03 + F81534_UART_BASE_ADDRESS)
+#define F81534_MODEM_CONTROL_REG       (0x04 + F81534_UART_BASE_ADDRESS)
+#define F81534_MODEM_STATUS_REG                (0x06 + F81534_UART_BASE_ADDRESS)
+#define F81534_CONFIG1_REG             (0x09 + F81534_UART_BASE_ADDRESS)
+
+#define F81534_DEF_CONF_ADDRESS_START  0x3000
+#define F81534_DEF_CONF_SIZE           8
+
+#define F81534_CUSTOM_ADDRESS_START    0x2f00
+#define F81534_CUSTOM_DATA_SIZE                0x10
+#define F81534_CUSTOM_NO_CUSTOM_DATA   0xff
+#define F81534_CUSTOM_VALID_TOKEN      0xf0
+#define F81534_CONF_OFFSET             1
+
+#define F81534_MAX_DATA_BLOCK          64
+#define F81534_MAX_BUS_RETRY           20
+
+/* Default URB timeout for USB operations */
+#define F81534_USB_MAX_RETRY           10
+#define F81534_USB_TIMEOUT             1000
+#define F81534_SET_GET_REGISTER                0xA0
+
+#define F81534_NUM_PORT                        4
+#define F81534_UNUSED_PORT             0xff
+#define F81534_WRITE_BUFFER_SIZE       512
+
+#define DRIVER_DESC                    "Fintek F81532/F81534"
+#define FINTEK_VENDOR_ID_1             0x1934
+#define FINTEK_VENDOR_ID_2             0x2C42
+#define FINTEK_DEVICE_ID               0x1202
+#define F81534_MAX_TX_SIZE             124
+#define F81534_MAX_RX_SIZE             124
+#define F81534_RECEIVE_BLOCK_SIZE      128
+#define F81534_MAX_RECEIVE_BLOCK_SIZE  512
+
+#define F81534_TOKEN_RECEIVE           0x01
+#define F81534_TOKEN_WRITE             0x02
+#define F81534_TOKEN_TX_EMPTY          0x03
+#define F81534_TOKEN_MSR_CHANGE                0x04
+
+/*
+ * We used interal SPI bus to access FLASH section. We must wait the SPI bus to
+ * idle if we performed any command.
+ *
+ * SPI Bus status register: F81534_BUS_REG_STATUS
+ *     Bit 0/1 : BUSY
+ *     Bit 2   : IDLE
+ */
+#define F81534_BUS_BUSY                        (BIT(0) | BIT(1))
+#define F81534_BUS_IDLE                        BIT(2)
+#define F81534_BUS_READ_DATA           0x1004
+#define F81534_BUS_REG_STATUS          0x1003
+#define F81534_BUS_REG_START           0x1002
+#define F81534_BUS_REG_END             0x1001
+
+#define F81534_CMD_READ                        0x03
+
+#define F81534_DEFAULT_BAUD_RATE       9600
+#define F81534_MAX_BAUDRATE            115200
+
+#define F81534_PORT_CONF_DISABLE_PORT  BIT(3)
+#define F81534_PORT_CONF_NOT_EXIST_PORT        BIT(7)
+#define F81534_PORT_UNAVAILABLE                \
+       (F81534_PORT_CONF_DISABLE_PORT | F81534_PORT_CONF_NOT_EXIST_PORT)
+
+#define F81534_1X_RXTRIGGER            0xc3
+#define F81534_8X_RXTRIGGER            0xcf
+
+static const struct usb_device_id f81534_id_table[] = {
+       { USB_DEVICE(FINTEK_VENDOR_ID_1, FINTEK_DEVICE_ID) },
+       { USB_DEVICE(FINTEK_VENDOR_ID_2, FINTEK_DEVICE_ID) },
+       {}                      /* Terminating entry */
+};
+
+#define F81534_TX_EMPTY_BIT            0
+
+struct f81534_serial_private {
+       u8 conf_data[F81534_DEF_CONF_SIZE];
+       int tty_idx[F81534_NUM_PORT];
+       u8 setting_idx;
+       int opened_port;
+       struct mutex urb_mutex;
+};
+
+struct f81534_port_private {
+       struct mutex mcr_mutex;
+       unsigned long tx_empty;
+       spinlock_t msr_lock;
+       u8 shadow_mcr;
+       u8 shadow_msr;
+       u8 phy_num;
+};
+
+static int f81534_logic_to_phy_port(struct usb_serial *serial,
+                                       struct usb_serial_port *port)
+{
+       struct f81534_serial_private *serial_priv =
+                       usb_get_serial_data(port->serial);
+       int count = 0;
+       int i;
+
+       for (i = 0; i < F81534_NUM_PORT; ++i) {
+               if (serial_priv->conf_data[i] & F81534_PORT_UNAVAILABLE)
+                       continue;
+
+               if (port->port_number == count)
+                       return i;
+
+               ++count;
+       }
+
+       return -ENODEV;
+}
+
+static int f81534_set_register(struct usb_serial *serial, u16 reg, u8 data)
+{
+       struct usb_interface *interface = serial->interface;
+       struct usb_device *dev = serial->dev;
+       size_t count = F81534_USB_MAX_RETRY;
+       int status;
+       u8 *tmp;
+
+       tmp = kmalloc(sizeof(u8), GFP_KERNEL);
+       if (!tmp)
+               return -ENOMEM;
+
+       *tmp = data;
+
+       /*
+        * Our device maybe not reply when heavily loading, We'll retry for
+        * F81534_USB_MAX_RETRY times.
+        */
+       while (count--) {
+               status = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+                                        F81534_SET_GET_REGISTER,
+                                        USB_TYPE_VENDOR | USB_DIR_OUT,
+                                        reg, 0, tmp, sizeof(u8),
+                                        F81534_USB_TIMEOUT);
+               if (status > 0) {
+                       status = 0;
+                       break;
+               } else if (status == 0) {
+                       status = -EIO;
+               }
+       }
+
+       if (status < 0) {
+               dev_err(&interface->dev, "%s: reg: %x data: %x failed: %d\n",
+                               __func__, reg, data, status);
+       }
+
+       kfree(tmp);
+       return status;
+}
+
+static int f81534_get_register(struct usb_serial *serial, u16 reg, u8 *data)
+{
+       struct usb_interface *interface = serial->interface;
+       struct usb_device *dev = serial->dev;
+       size_t count = F81534_USB_MAX_RETRY;
+       int status;
+       u8 *tmp;
+
+       tmp = kmalloc(sizeof(u8), GFP_KERNEL);
+       if (!tmp)
+               return -ENOMEM;
+
+       /*
+        * Our device maybe not reply when heavily loading, We'll retry for
+        * F81534_USB_MAX_RETRY times.
+        */
+       while (count--) {
+               status = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
+                                        F81534_SET_GET_REGISTER,
+                                        USB_TYPE_VENDOR | USB_DIR_IN,
+                                        reg, 0, tmp, sizeof(u8),
+                                        F81534_USB_TIMEOUT);
+               if (status > 0) {
+                       status = 0;
+                       break;
+               } else if (status == 0) {
+                       status = -EIO;
+               }
+       }
+
+       if (status < 0) {
+               dev_err(&interface->dev, "%s: reg: %x failed: %d\n", __func__,
+                               reg, status);
+               goto end;
+       }
+
+       *data = *tmp;
+
+end:
+       kfree(tmp);
+       return status;
+}
+
+static int f81534_set_port_register(struct usb_serial_port *port, u16 reg,
+                                       u8 data)
+{
+       struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+
+       return f81534_set_register(port->serial,
+                       reg + port_priv->phy_num * F81534_UART_OFFSET, data);
+}
+
+static int f81534_get_port_register(struct usb_serial_port *port, u16 reg,
+                                       u8 *data)
+{
+       struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+
+       return f81534_get_register(port->serial,
+                       reg + port_priv->phy_num * F81534_UART_OFFSET, data);
+}
+
+/*
+ * If we try to access the internal flash via SPI bus, we should check the bus
+ * status for every command. e.g., F81534_BUS_REG_START/F81534_BUS_REG_END
+ */
+static int f81534_wait_for_spi_idle(struct usb_serial *serial)
+{
+       size_t count = F81534_MAX_BUS_RETRY;
+       u8 tmp;
+       int status;
+
+       do {
+               status = f81534_get_register(serial, F81534_BUS_REG_STATUS,
+                                               &tmp);
+               if (status)
+                       return status;
+
+               if (tmp & F81534_BUS_BUSY)
+                       continue;
+
+               if (tmp & F81534_BUS_IDLE)
+                       break;
+
+       } while (--count);
+
+       if (!count) {
+               dev_err(&serial->interface->dev,
+                               "%s: timed out waiting for idle SPI bus\n",
+                               __func__);
+               return -EIO;
+       }
+
+       return f81534_set_register(serial, F81534_BUS_REG_STATUS,
+                               tmp & ~F81534_BUS_IDLE);
+}
+
+static int f81534_get_spi_register(struct usb_serial *serial, u16 reg,
+                                       u8 *data)
+{
+       int status;
+
+       status = f81534_get_register(serial, reg, data);
+       if (status)
+               return status;
+
+       return f81534_wait_for_spi_idle(serial);
+}
+
+static int f81534_set_spi_register(struct usb_serial *serial, u16 reg, u8 data)
+{
+       int status;
+
+       status = f81534_set_register(serial, reg, data);
+       if (status)
+               return status;
+
+       return f81534_wait_for_spi_idle(serial);
+}
+
+static int f81534_read_flash(struct usb_serial *serial, u32 address,
+                               size_t size, u8 *buf)
+{
+       u8 tmp_buf[F81534_MAX_DATA_BLOCK];
+       size_t block = 0;
+       size_t read_size;
+       size_t count;
+       int status;
+       int offset;
+       u16 reg_tmp;
+
+       status = f81534_set_spi_register(serial, F81534_BUS_REG_START,
+                                       F81534_CMD_READ);
+       if (status)
+               return status;
+
+       status = f81534_set_spi_register(serial, F81534_BUS_REG_START,
+                                       (address >> 16) & 0xff);
+       if (status)
+               return status;
+
+       status = f81534_set_spi_register(serial, F81534_BUS_REG_START,
+                                       (address >> 8) & 0xff);
+       if (status)
+               return status;
+
+       status = f81534_set_spi_register(serial, F81534_BUS_REG_START,
+                                       (address >> 0) & 0xff);
+       if (status)
+               return status;
+
+       /* Continuous read mode */
+       do {
+               read_size = min_t(size_t, F81534_MAX_DATA_BLOCK, size);
+
+               for (count = 0; count < read_size; ++count) {
+                       /* To write F81534_BUS_REG_END when final byte */
+                       if (size <= F81534_MAX_DATA_BLOCK &&
+                                       read_size == count + 1)
+                               reg_tmp = F81534_BUS_REG_END;
+                       else
+                               reg_tmp = F81534_BUS_REG_START;
+
+                       /*
+                        * Dummy code, force IC to generate a read pulse, the
+                        * set of value 0xf1 is dont care (any value is ok)
+                        */
+                       status = f81534_set_spi_register(serial, reg_tmp,
+                                       0xf1);
+                       if (status)
+                               return status;
+
+                       status = f81534_get_spi_register(serial,
+                                               F81534_BUS_READ_DATA,
+                                               &tmp_buf[count]);
+                       if (status)
+                               return status;
+
+                       offset = count + block * F81534_MAX_DATA_BLOCK;
+                       buf[offset] = tmp_buf[count];
+               }
+
+               size -= read_size;
+               ++block;
+       } while (size);
+
+       return 0;
+}
+
+static void f81534_prepare_write_buffer(struct usb_serial_port *port, u8 *buf)
+{
+       struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+       int phy_num = port_priv->phy_num;
+       u8 tx_len;
+       int i;
+
+       /*
+        * The block layout is fixed with 4x128 Bytes, per 128 Bytes a port.
+        * index 0: port phy idx (e.g., 0,1,2,3)
+        * index 1: only F81534_TOKEN_WRITE
+        * index 2: serial TX out length
+        * index 3: fix to 0
+        * index 4~127: serial out data block
+        */
+       for (i = 0; i < F81534_NUM_PORT; ++i) {
+               buf[i * F81534_RECEIVE_BLOCK_SIZE] = i;
+               buf[i * F81534_RECEIVE_BLOCK_SIZE + 1] = F81534_TOKEN_WRITE;
+               buf[i * F81534_RECEIVE_BLOCK_SIZE + 2] = 0;
+               buf[i * F81534_RECEIVE_BLOCK_SIZE + 3] = 0;
+       }
+
+       tx_len = kfifo_out_locked(&port->write_fifo,
+                               &buf[phy_num * F81534_RECEIVE_BLOCK_SIZE + 4],
+                               F81534_MAX_TX_SIZE, &port->lock);
+
+       buf[phy_num * F81534_RECEIVE_BLOCK_SIZE + 2] = tx_len;
+}
+
+static int f81534_submit_writer(struct usb_serial_port *port, gfp_t mem_flags)
+{
+       struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+       struct urb *urb;
+       unsigned long flags;
+       int result;
+
+       /* Check is any data in write_fifo */
+       spin_lock_irqsave(&port->lock, flags);
+
+       if (kfifo_is_empty(&port->write_fifo)) {
+               spin_unlock_irqrestore(&port->lock, flags);
+               return 0;
+       }
+
+       spin_unlock_irqrestore(&port->lock, flags);
+
+       /* Check H/W is TXEMPTY */
+       if (!test_and_clear_bit(F81534_TX_EMPTY_BIT, &port_priv->tx_empty))
+               return 0;
+
+       urb = port->write_urbs[0];
+       f81534_prepare_write_buffer(port, port->bulk_out_buffers[0]);
+       urb->transfer_buffer_length = F81534_WRITE_BUFFER_SIZE;
+
+       result = usb_submit_urb(urb, mem_flags);
+       if (result) {
+               set_bit(F81534_TX_EMPTY_BIT, &port_priv->tx_empty);
+               dev_err(&port->dev, "%s: submit failed: %d\n", __func__,
+                               result);
+               return result;
+       }
+
+       usb_serial_port_softint(port);
+       return 0;
+}
+
+static u32 f81534_calc_baud_divisor(u32 baudrate, u32 clockrate)
+{
+       if (!baudrate)
+               return 0;
+
+       /* Round to nearest divisor */
+       return DIV_ROUND_CLOSEST(clockrate, baudrate);
+}
+
+static int f81534_set_port_config(struct usb_serial_port *port, u32 baudrate,
+                                       u8 lcr)
+{
+       u32 divisor;
+       int status;
+       u8 value;
+
+       if (baudrate <= 1200)
+               value = F81534_1X_RXTRIGGER;    /* 128 FIFO & TL: 1x */
+       else
+               value = F81534_8X_RXTRIGGER;    /* 128 FIFO & TL: 8x */
+
+       status = f81534_set_port_register(port, F81534_CONFIG1_REG, value);
+       if (status) {
+               dev_err(&port->dev, "%s: CONFIG1 setting failed\n", __func__);
+               return status;
+       }
+
+       if (baudrate <= 1200)
+               value = UART_FCR_TRIGGER_1 | UART_FCR_ENABLE_FIFO; /* TL: 1 */
+       else
+               value = UART_FCR_R_TRIG_11 | UART_FCR_ENABLE_FIFO; /* TL: 14 */
+
+       status = f81534_set_port_register(port, F81534_FIFO_CONTROL_REG,
+                                               value);
+       if (status) {
+               dev_err(&port->dev, "%s: FCR setting failed\n", __func__);
+               return status;
+       }
+
+       divisor = f81534_calc_baud_divisor(baudrate, F81534_MAX_BAUDRATE);
+       value = UART_LCR_DLAB;
+       status = f81534_set_port_register(port, F81534_LINE_CONTROL_REG,
+                                               value);
+       if (status) {
+               dev_err(&port->dev, "%s: set LCR failed\n", __func__);
+               return status;
+       }
+
+       value = divisor & 0xff;
+       status = f81534_set_port_register(port, F81534_DIVISOR_LSB_REG, value);
+       if (status) {
+               dev_err(&port->dev, "%s: set DLAB LSB failed\n", __func__);
+               return status;
+       }
+
+       value = (divisor >> 8) & 0xff;
+       status = f81534_set_port_register(port, F81534_DIVISOR_MSB_REG, value);
+       if (status) {
+               dev_err(&port->dev, "%s: set DLAB MSB failed\n", __func__);
+               return status;
+       }
+
+       status = f81534_set_port_register(port, F81534_LINE_CONTROL_REG, lcr);
+       if (status) {
+               dev_err(&port->dev, "%s: set LCR failed\n", __func__);
+               return status;
+       }
+
+       return 0;
+}
+
+static int f81534_update_mctrl(struct usb_serial_port *port, unsigned int set,
+                               unsigned int clear)
+{
+       struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+       int status;
+       u8 tmp;
+
+       if (((set | clear) & (TIOCM_DTR | TIOCM_RTS)) == 0)
+               return 0;       /* no change */
+
+       mutex_lock(&port_priv->mcr_mutex);
+
+       /* 'Set' takes precedence over 'Clear' */
+       clear &= ~set;
+
+       /* Always enable UART_MCR_OUT2 */
+       tmp = UART_MCR_OUT2 | port_priv->shadow_mcr;
+
+       if (clear & TIOCM_DTR)
+               tmp &= ~UART_MCR_DTR;
+
+       if (clear & TIOCM_RTS)
+               tmp &= ~UART_MCR_RTS;
+
+       if (set & TIOCM_DTR)
+               tmp |= UART_MCR_DTR;
+
+       if (set & TIOCM_RTS)
+               tmp |= UART_MCR_RTS;
+
+       status = f81534_set_port_register(port, F81534_MODEM_CONTROL_REG, tmp);
+       if (status < 0) {
+               dev_err(&port->dev, "%s: MCR write failed\n", __func__);
+               mutex_unlock(&port_priv->mcr_mutex);
+               return status;
+       }
+
+       port_priv->shadow_mcr = tmp;
+       mutex_unlock(&port_priv->mcr_mutex);
+       return 0;
+}
+
+/*
+ * This function will search the data area with token F81534_CUSTOM_VALID_TOKEN
+ * for latest configuration index. If nothing found
+ * (*index = F81534_CUSTOM_NO_CUSTOM_DATA), We'll load default configure in
+ * F81534_DEF_CONF_ADDRESS_START section.
+ *
+ * Due to we only use block0 to save data, so *index should be 0 or
+ * F81534_CUSTOM_NO_CUSTOM_DATA.
+ */
+static int f81534_find_config_idx(struct usb_serial *serial, u8 *index)
+{
+       u8 tmp;
+       int status;
+
+       status = f81534_read_flash(serial, F81534_CUSTOM_ADDRESS_START, 1,
+                                       &tmp);
+       if (status) {
+               dev_err(&serial->interface->dev, "%s: read failed: %d\n",
+                               __func__, status);
+               return status;
+       }
+
+       /* We'll use the custom data when the data is valid. */
+       if (tmp == F81534_CUSTOM_VALID_TOKEN)
+               *index = 0;
+       else
+               *index = F81534_CUSTOM_NO_CUSTOM_DATA;
+
+       return 0;
+}
+
+/*
+ * We had 2 generation of F81532/534 IC. All has an internal storage.
+ *
+ * 1st is pure USB-to-TTL RS232 IC and designed for 4 ports only, no any
+ * internal data will used. All mode and gpio control should manually set
+ * by AP or Driver and all storage space value are 0xff. The
+ * f81534_calc_num_ports() will run to final we marked as "oldest version"
+ * for this IC.
+ *
+ * 2rd is designed to more generic to use any transceiver and this is our
+ * mass production type. We'll save data in F81534_CUSTOM_ADDRESS_START
+ * (0x2f00) with 9bytes. The 1st byte is a indicater. If the token is
+ * F81534_CUSTOM_VALID_TOKEN(0xf0), the IC is 2nd gen type, the following
+ * 4bytes save port mode (0:RS232/1:RS485 Invert/2:RS485), and the last
+ * 4bytes save GPIO state(value from 0~7 to represent 3 GPIO output pin).
+ * The f81534_calc_num_ports() will run to "new style" with checking
+ * F81534_PORT_UNAVAILABLE section.
+ */
+static int f81534_calc_num_ports(struct usb_serial *serial)
+{
+       u8 setting[F81534_CUSTOM_DATA_SIZE];
+       u8 setting_idx;
+       u8 num_port = 0;
+       int status;
+       size_t i;
+
+       /* Check had custom setting */
+       status = f81534_find_config_idx(serial, &setting_idx);
+       if (status) {
+               dev_err(&serial->interface->dev, "%s: find idx failed: %d\n",
+                               __func__, status);
+               return 0;
+       }
+
+       /*
+        * We'll read custom data only when data available, otherwise we'll
+        * read default value instead.
+        */
+       if (setting_idx != F81534_CUSTOM_NO_CUSTOM_DATA) {
+               status = f81534_read_flash(serial,
+                                               F81534_CUSTOM_ADDRESS_START +
+                                               F81534_CONF_OFFSET,
+                                               sizeof(setting), setting);
+               if (status) {
+                       dev_err(&serial->interface->dev,
+                                       "%s: get custom data failed: %d\n",
+                                       __func__, status);
+                       return 0;
+               }
+
+               dev_dbg(&serial->interface->dev,
+                               "%s: read config from block: %d\n", __func__,
+                               setting_idx);
+       } else {
+               /* Read default board setting */
+               status = f81534_read_flash(serial,
+                               F81534_DEF_CONF_ADDRESS_START, F81534_NUM_PORT,
+                               setting);
+
+               if (status) {
+                       dev_err(&serial->interface->dev,
+                                       "%s: read failed: %d\n", __func__,
+                                       status);
+                       return 0;
+               }
+
+               dev_dbg(&serial->interface->dev, "%s: read default config\n",
+                               __func__);
+       }
+
+       /* New style, find all possible ports */
+       for (i = 0; i < F81534_NUM_PORT; ++i) {
+               if (setting[i] & F81534_PORT_UNAVAILABLE)
+                       continue;
+
+               ++num_port;
+       }
+
+       if (num_port)
+               return num_port;
+
+       dev_warn(&serial->interface->dev, "%s: Read Failed. default 4 ports\n",
+                       __func__);
+       return 4;               /* Nothing found, oldest version IC */
+}
+
+static void f81534_set_termios(struct tty_struct *tty,
+                               struct usb_serial_port *port,
+                               struct ktermios *old_termios)
+{
+       u8 new_lcr = 0;
+       int status;
+       u32 baud;
+
+       if (C_BAUD(tty) == B0)
+               f81534_update_mctrl(port, 0, TIOCM_DTR | TIOCM_RTS);
+       else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
+               f81534_update_mctrl(port, TIOCM_DTR | TIOCM_RTS, 0);
+
+       if (C_PARENB(tty)) {
+               new_lcr |= UART_LCR_PARITY;
+
+               if (!C_PARODD(tty))
+                       new_lcr |= UART_LCR_EPAR;
+
+               if (C_CMSPAR(tty))
+                       new_lcr |= UART_LCR_SPAR;
+       }
+
+       if (C_CSTOPB(tty))
+               new_lcr |= UART_LCR_STOP;
+
+       switch (C_CSIZE(tty)) {
+       case CS5:
+               new_lcr |= UART_LCR_WLEN5;
+               break;
+       case CS6:
+               new_lcr |= UART_LCR_WLEN6;
+               break;
+       case CS7:
+               new_lcr |= UART_LCR_WLEN7;
+               break;
+       default:
+       case CS8:
+               new_lcr |= UART_LCR_WLEN8;
+               break;
+       }
+
+       baud = tty_get_baud_rate(tty);
+       if (!baud)
+               return;
+
+       if (baud > F81534_MAX_BAUDRATE) {
+               if (old_termios)
+                       baud = tty_termios_baud_rate(old_termios);
+               else
+                       baud = F81534_DEFAULT_BAUD_RATE;
+
+               tty_encode_baud_rate(tty, baud, baud);
+       }
+
+       dev_dbg(&port->dev, "%s: baud: %d\n", __func__, baud);
+
+       status = f81534_set_port_config(port, baud, new_lcr);
+       if (status < 0) {
+               dev_err(&port->dev, "%s: set port config failed: %d\n",
+                               __func__, status);
+       }
+}
+
+static int f81534_submit_read_urb(struct usb_serial *serial, gfp_t flags)
+{
+       return usb_serial_generic_submit_read_urbs(serial->port[0], flags);
+}
+
+static void f81534_msr_changed(struct usb_serial_port *port, u8 msr)
+{
+       struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+       struct tty_struct *tty;
+       unsigned long flags;
+       u8 old_msr;
+
+       if (!(msr & UART_MSR_ANY_DELTA))
+               return;
+
+       spin_lock_irqsave(&port_priv->msr_lock, flags);
+       old_msr = port_priv->shadow_msr;
+       port_priv->shadow_msr = msr;
+       spin_unlock_irqrestore(&port_priv->msr_lock, flags);
+
+       dev_dbg(&port->dev, "%s: MSR from %02x to %02x\n", __func__, old_msr,
+                       msr);
+
+       /* Update input line counters */
+       if (msr & UART_MSR_DCTS)
+               port->icount.cts++;
+       if (msr & UART_MSR_DDSR)
+               port->icount.dsr++;
+       if (msr & UART_MSR_DDCD)
+               port->icount.dcd++;
+       if (msr & UART_MSR_TERI)
+               port->icount.rng++;
+
+       wake_up_interruptible(&port->port.delta_msr_wait);
+
+       if (!(msr & UART_MSR_DDCD))
+               return;
+
+       dev_dbg(&port->dev, "%s: DCD Changed: phy_num: %d from %x to %x\n",
+                       __func__, port_priv->phy_num, old_msr, msr);
+
+       tty = tty_port_tty_get(&port->port);
+       if (!tty)
+               return;
+
+       usb_serial_handle_dcd_change(port, tty, msr & UART_MSR_DCD);
+       tty_kref_put(tty);
+}
+
+static int f81534_read_msr(struct usb_serial_port *port)
+{
+       struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+       unsigned long flags;
+       int status;
+       u8 msr;
+
+       /* Get MSR initial value */
+       status = f81534_get_port_register(port, F81534_MODEM_STATUS_REG, &msr);
+       if (status)
+               return status;
+
+       /* Force update current state */
+       spin_lock_irqsave(&port_priv->msr_lock, flags);
+       port_priv->shadow_msr = msr;
+       spin_unlock_irqrestore(&port_priv->msr_lock, flags);
+
+       return 0;
+}
+
+static int f81534_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+       struct f81534_serial_private *serial_priv =
+                       usb_get_serial_data(port->serial);
+       struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+       int status;
+
+       status = f81534_set_port_register(port,
+                               F81534_FIFO_CONTROL_REG, UART_FCR_ENABLE_FIFO |
+                               UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+       if (status) {
+               dev_err(&port->dev, "%s: Clear FIFO failed: %d\n", __func__,
+                               status);
+               return status;
+       }
+
+       if (tty)
+               f81534_set_termios(tty, port, NULL);
+
+       status = f81534_read_msr(port);
+       if (status)
+               return status;
+
+       mutex_lock(&serial_priv->urb_mutex);
+
+       /* Submit Read URBs for first port opened */
+       if (!serial_priv->opened_port) {
+               status = f81534_submit_read_urb(port->serial, GFP_KERNEL);
+               if (status)
+                       goto exit;
+       }
+
+       serial_priv->opened_port++;
+
+exit:
+       mutex_unlock(&serial_priv->urb_mutex);
+
+       set_bit(F81534_TX_EMPTY_BIT, &port_priv->tx_empty);
+       return status;
+}
+
+static void f81534_close(struct usb_serial_port *port)
+{
+       struct f81534_serial_private *serial_priv =
+                       usb_get_serial_data(port->serial);
+       struct usb_serial_port *port0 = port->serial->port[0];
+       unsigned long flags;
+       size_t i;
+
+       usb_kill_urb(port->write_urbs[0]);
+
+       spin_lock_irqsave(&port->lock, flags);
+       kfifo_reset_out(&port->write_fifo);
+       spin_unlock_irqrestore(&port->lock, flags);
+
+       /* Kill Read URBs when final port closed */
+       mutex_lock(&serial_priv->urb_mutex);
+       serial_priv->opened_port--;
+
+       if (!serial_priv->opened_port) {
+               for (i = 0; i < ARRAY_SIZE(port0->read_urbs); ++i)
+                       usb_kill_urb(port0->read_urbs[i]);
+       }
+
+       mutex_unlock(&serial_priv->urb_mutex);
+}
+
+static int f81534_get_serial_info(struct usb_serial_port *port,
+                                 struct serial_struct __user *retinfo)
+{
+       struct f81534_port_private *port_priv;
+       struct serial_struct tmp;
+
+       port_priv = usb_get_serial_port_data(port);
+
+       memset(&tmp, 0, sizeof(tmp));
+
+       tmp.type = PORT_16550A;
+       tmp.port = port->port_number;
+       tmp.line = port->minor;
+       tmp.baud_base = F81534_MAX_BAUDRATE;
+
+       if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
+               return -EFAULT;
+
+       return 0;
+}
+
+static int f81534_ioctl(struct tty_struct *tty, unsigned int cmd,
+                       unsigned long arg)
+{
+       struct usb_serial_port *port = tty->driver_data;
+       struct serial_struct __user *buf = (struct serial_struct __user *)arg;
+
+       switch (cmd) {
+       case TIOCGSERIAL:
+               return f81534_get_serial_info(port, buf);
+       default:
+               break;
+       }
+
+       return -ENOIOCTLCMD;
+}
+
+static void f81534_process_per_serial_block(struct usb_serial_port *port,
+               u8 *data)
+{
+       struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+       int phy_num = data[0];
+       size_t read_size = 0;
+       size_t i;
+       char tty_flag;
+       int status;
+       u8 lsr;
+
+       /*
+        * The block layout is 128 Bytes
+        * index 0: port phy idx (e.g., 0,1,2,3),
+        * index 1: It's could be
+        *                      F81534_TOKEN_RECEIVE
+        *                      F81534_TOKEN_TX_EMPTY
+        *                      F81534_TOKEN_MSR_CHANGE
+        * index 2: serial in size (data+lsr, must be even)
+        *                      meaningful for F81534_TOKEN_RECEIVE only
+        * index 3: current MSR with this device
+        * index 4~127: serial in data block (data+lsr, must be even)
+        */
+       switch (data[1]) {
+       case F81534_TOKEN_TX_EMPTY:
+               set_bit(F81534_TX_EMPTY_BIT, &port_priv->tx_empty);
+
+               /* Try to submit writer */
+               status = f81534_submit_writer(port, GFP_ATOMIC);
+               if (status)
+                       dev_err(&port->dev, "%s: submit failed\n", __func__);
+               return;
+
+       case F81534_TOKEN_MSR_CHANGE:
+               f81534_msr_changed(port, data[3]);
+               return;
+
+       case F81534_TOKEN_RECEIVE:
+               read_size = data[2];
+               if (read_size > F81534_MAX_RX_SIZE) {
+                       dev_err(&port->dev,
+                               "%s: phy: %d read_size: %zu larger than: %d\n",
+                               __func__, phy_num, read_size,
+                               F81534_MAX_RX_SIZE);
+                       return;
+               }
+
+               break;
+
+       default:
+               dev_warn(&port->dev, "%s: unknown token: %02x\n", __func__,
+                               data[1]);
+               return;
+       }
+
+       for (i = 4; i < 4 + read_size; i += 2) {
+               tty_flag = TTY_NORMAL;
+               lsr = data[i + 1];
+
+               if (lsr & UART_LSR_BRK_ERROR_BITS) {
+                       if (lsr & UART_LSR_BI) {
+                               tty_flag = TTY_BREAK;
+                               port->icount.brk++;
+                               usb_serial_handle_break(port);
+                       } else if (lsr & UART_LSR_PE) {
+                               tty_flag = TTY_PARITY;
+                               port->icount.parity++;
+                       } else if (lsr & UART_LSR_FE) {
+                               tty_flag = TTY_FRAME;
+                               port->icount.frame++;
+                       }
+
+                       if (lsr & UART_LSR_OE) {
+                               port->icount.overrun++;
+                               tty_insert_flip_char(&port->port, 0,
+                                               TTY_OVERRUN);
+                       }
+               }
+
+               if (port->port.console && port->sysrq) {
+                       if (usb_serial_handle_sysrq_char(port, data[i]))
+                               continue;
+               }
+
+               tty_insert_flip_char(&port->port, data[i], tty_flag);
+       }
+
+       tty_flip_buffer_push(&port->port);
+}
+
+static void f81534_process_read_urb(struct urb *urb)
+{
+       struct f81534_serial_private *serial_priv;
+       struct usb_serial_port *port;
+       struct usb_serial *serial;
+       u8 *buf;
+       int phy_port_num;
+       int tty_port_num;
+       size_t i;
+
+       if (!urb->actual_length ||
+                       urb->actual_length % F81534_RECEIVE_BLOCK_SIZE) {
+               return;
+       }
+
+       port = urb->context;
+       serial = port->serial;
+       buf = urb->transfer_buffer;
+       serial_priv = usb_get_serial_data(serial);
+
+       for (i = 0; i < urb->actual_length; i += F81534_RECEIVE_BLOCK_SIZE) {
+               phy_port_num = buf[i];
+               if (phy_port_num >= F81534_NUM_PORT) {
+                       dev_err(&port->dev,
+                               "%s: phy_port_num: %d larger than: %d\n",
+                               __func__, phy_port_num, F81534_NUM_PORT);
+                       continue;
+               }
+
+               tty_port_num = serial_priv->tty_idx[phy_port_num];
+               port = serial->port[tty_port_num];
+
+               if (tty_port_initialized(&port->port))
+                       f81534_process_per_serial_block(port, &buf[i]);
+       }
+}
+
+static void f81534_write_usb_callback(struct urb *urb)
+{
+       struct usb_serial_port *port = urb->context;
+
+       switch (urb->status) {
+       case 0:
+               break;
+       case -ENOENT:
+       case -ECONNRESET:
+       case -ESHUTDOWN:
+               dev_dbg(&port->dev, "%s - urb stopped: %d\n",
+                               __func__, urb->status);
+               return;
+       case -EPIPE:
+               dev_err(&port->dev, "%s - urb stopped: %d\n",
+                               __func__, urb->status);
+               return;
+       default:
+               dev_dbg(&port->dev, "%s - nonzero urb status: %d\n",
+                               __func__, urb->status);
+               break;
+       }
+}
+
+static int f81534_setup_ports(struct usb_serial *serial)
+{
+       struct usb_serial_port *port;
+       u8 port0_out_address;
+       int buffer_size;
+       size_t i;
+
+       /*
+        * In our system architecture, we had 2 or 4 serial ports,
+        * but only get 1 set of bulk in/out endpoints.
+        *
+        * The usb-serial subsystem will generate port 0 data,
+        * but port 1/2/3 will not. It's will generate write URB and buffer
+        * by following code and use the port0 read URB for read operation.
+        */
+       for (i = 1; i < serial->num_ports; ++i) {
+               port0_out_address = serial->port[0]->bulk_out_endpointAddress;
+               buffer_size = serial->port[0]->bulk_out_size;
+               port = serial->port[i];
+
+               if (kfifo_alloc(&port->write_fifo, PAGE_SIZE, GFP_KERNEL))
+                       return -ENOMEM;
+
+               port->bulk_out_size = buffer_size;
+               port->bulk_out_endpointAddress = port0_out_address;
+
+               port->write_urbs[0] = usb_alloc_urb(0, GFP_KERNEL);
+               if (!port->write_urbs[0])
+                       return -ENOMEM;
+
+               port->bulk_out_buffers[0] = kzalloc(buffer_size, GFP_KERNEL);
+               if (!port->bulk_out_buffers[0])
+                       return -ENOMEM;
+
+               usb_fill_bulk_urb(port->write_urbs[0], serial->dev,
+                               usb_sndbulkpipe(serial->dev,
+                                       port0_out_address),
+                               port->bulk_out_buffers[0], buffer_size,
+                               serial->type->write_bulk_callback, port);
+
+               port->write_urb = port->write_urbs[0];
+               port->bulk_out_buffer = port->bulk_out_buffers[0];
+       }
+
+       return 0;
+}
+
+static int f81534_probe(struct usb_serial *serial,
+                                       const struct usb_device_id *id)
+{
+       struct usb_endpoint_descriptor *endpoint;
+       struct usb_host_interface *iface_desc;
+       struct device *dev;
+       int num_bulk_in = 0;
+       int num_bulk_out = 0;
+       int size_bulk_in = 0;
+       int size_bulk_out = 0;
+       int i;
+
+       dev = &serial->interface->dev;
+       iface_desc = serial->interface->cur_altsetting;
+
+       for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
+               endpoint = &iface_desc->endpoint[i].desc;
+
+               if (usb_endpoint_is_bulk_in(endpoint)) {
+                       ++num_bulk_in;
+                       size_bulk_in = usb_endpoint_maxp(endpoint);
+               }
+
+               if (usb_endpoint_is_bulk_out(endpoint)) {
+                       ++num_bulk_out;
+                       size_bulk_out = usb_endpoint_maxp(endpoint);
+               }
+       }
+
+       if (num_bulk_in != 1 || num_bulk_out != 1) {
+               dev_err(dev, "expected endpoints not found\n");
+               return -ENODEV;
+       }
+
+       if (size_bulk_out != F81534_WRITE_BUFFER_SIZE ||
+                       size_bulk_in != F81534_MAX_RECEIVE_BLOCK_SIZE) {
+               dev_err(dev, "unsupported endpoint max packet size\n");
+               return -ENODEV;
+       }
+
+       return 0;
+}
+
+static int f81534_attach(struct usb_serial *serial)
+{
+       struct f81534_serial_private *serial_priv;
+       int index = 0;
+       int status;
+       int i;
+
+       serial_priv = devm_kzalloc(&serial->interface->dev,
+                                       sizeof(*serial_priv), GFP_KERNEL);
+       if (!serial_priv)
+               return -ENOMEM;
+
+       usb_set_serial_data(serial, serial_priv);
+
+       mutex_init(&serial_priv->urb_mutex);
+
+       status = f81534_setup_ports(serial);
+       if (status)
+               return status;
+
+       /* Check had custom setting */
+       status = f81534_find_config_idx(serial, &serial_priv->setting_idx);
+       if (status) {
+               dev_err(&serial->interface->dev, "%s: find idx failed: %d\n",
+                               __func__, status);
+               return status;
+       }
+
+       /*
+        * We'll read custom data only when data available, otherwise we'll
+        * read default value instead.
+        */
+       if (serial_priv->setting_idx == F81534_CUSTOM_NO_CUSTOM_DATA) {
+               /*
+                * The default configuration layout:
+                *      byte 0/1/2/3: uart setting
+                */
+               status = f81534_read_flash(serial,
+                                       F81534_DEF_CONF_ADDRESS_START,
+                                       F81534_DEF_CONF_SIZE,
+                                       serial_priv->conf_data);
+               if (status) {
+                       dev_err(&serial->interface->dev,
+                                       "%s: read reserve data failed: %d\n",
+                                       __func__, status);
+                       return status;
+               }
+       } else {
+               /* Only read 8 bytes for mode & GPIO */
+               status = f81534_read_flash(serial,
+                                               F81534_CUSTOM_ADDRESS_START +
+                                               F81534_CONF_OFFSET,
+                                               sizeof(serial_priv->conf_data),
+                                               serial_priv->conf_data);
+               if (status) {
+                       dev_err(&serial->interface->dev,
+                                       "%s: idx: %d get data failed: %d\n",
+                                       __func__, serial_priv->setting_idx,
+                                       status);
+                       return status;
+               }
+       }
+
+       /* Assign phy-to-logic mapping */
+       for (i = 0; i < F81534_NUM_PORT; ++i) {
+               if (serial_priv->conf_data[i] & F81534_PORT_UNAVAILABLE)
+                       continue;
+
+               serial_priv->tty_idx[i] = index++;
+               dev_dbg(&serial->interface->dev,
+                               "%s: phy_num: %d, tty_idx: %d\n", __func__, i,
+                               serial_priv->tty_idx[i]);
+       }
+
+       return 0;
+}
+
+static int f81534_port_probe(struct usb_serial_port *port)
+{
+       struct f81534_port_private *port_priv;
+
+       port_priv = devm_kzalloc(&port->dev, sizeof(*port_priv), GFP_KERNEL);
+       if (!port_priv)
+               return -ENOMEM;
+
+       spin_lock_init(&port_priv->msr_lock);
+       mutex_init(&port_priv->mcr_mutex);
+
+       /* Assign logic-to-phy mapping */
+       port_priv->phy_num = f81534_logic_to_phy_port(port->serial, port);
+       if (port_priv->phy_num < 0 || port_priv->phy_num >= F81534_NUM_PORT)
+               return -ENODEV;
+
+       usb_set_serial_port_data(port, port_priv);
+       dev_dbg(&port->dev, "%s: port_number: %d, phy_num: %d\n", __func__,
+                       port->port_number, port_priv->phy_num);
+
+       return 0;
+}
+
+static int f81534_tiocmget(struct tty_struct *tty)
+{
+       struct usb_serial_port *port = tty->driver_data;
+       struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+       int status;
+       int r;
+       u8 msr;
+       u8 mcr;
+
+       /* Read current MSR from device */
+       status = f81534_get_port_register(port, F81534_MODEM_STATUS_REG, &msr);
+       if (status)
+               return status;
+
+       mutex_lock(&port_priv->mcr_mutex);
+       mcr = port_priv->shadow_mcr;
+       mutex_unlock(&port_priv->mcr_mutex);
+
+       r = (mcr & UART_MCR_DTR ? TIOCM_DTR : 0) |
+           (mcr & UART_MCR_RTS ? TIOCM_RTS : 0) |
+           (msr & UART_MSR_CTS ? TIOCM_CTS : 0) |
+           (msr & UART_MSR_DCD ? TIOCM_CAR : 0) |
+           (msr & UART_MSR_RI ? TIOCM_RI : 0) |
+           (msr & UART_MSR_DSR ? TIOCM_DSR : 0);
+
+       return r;
+}
+
+static int f81534_tiocmset(struct tty_struct *tty, unsigned int set,
+                               unsigned int clear)
+{
+       struct usb_serial_port *port = tty->driver_data;
+
+       return f81534_update_mctrl(port, set, clear);
+}
+
+static void f81534_dtr_rts(struct usb_serial_port *port, int on)
+{
+       if (on)
+               f81534_update_mctrl(port, TIOCM_DTR | TIOCM_RTS, 0);
+       else
+               f81534_update_mctrl(port, 0, TIOCM_DTR | TIOCM_RTS);
+}
+
+static int f81534_write(struct tty_struct *tty, struct usb_serial_port *port,
+                       const u8 *buf, int count)
+{
+       int bytes_out, status;
+
+       if (!count)
+               return 0;
+
+       bytes_out = kfifo_in_locked(&port->write_fifo, buf, count,
+                                       &port->lock);
+
+       status = f81534_submit_writer(port, GFP_ATOMIC);
+       if (status) {
+               dev_err(&port->dev, "%s: submit failed\n", __func__);
+               return status;
+       }
+
+       return bytes_out;
+}
+
+static bool f81534_tx_empty(struct usb_serial_port *port)
+{
+       struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+
+       return test_bit(F81534_TX_EMPTY_BIT, &port_priv->tx_empty);
+}
+
+static int f81534_resume(struct usb_serial *serial)
+{
+       struct f81534_serial_private *serial_priv =
+                       usb_get_serial_data(serial);
+       struct usb_serial_port *port;
+       int error = 0;
+       int status;
+       size_t i;
+
+       /*
+        * We'll register port 0 bulkin when port had opened, It'll take all
+        * port received data, MSR register change and TX_EMPTY information.
+        */
+       mutex_lock(&serial_priv->urb_mutex);
+
+       if (serial_priv->opened_port) {
+               status = f81534_submit_read_urb(serial, GFP_NOIO);
+               if (status) {
+                       mutex_unlock(&serial_priv->urb_mutex);
+                       return status;
+               }
+       }
+
+       mutex_unlock(&serial_priv->urb_mutex);
+
+       for (i = 0; i < serial->num_ports; i++) {
+               port = serial->port[i];
+               if (!tty_port_initialized(&port->port))
+                       continue;
+
+               status = f81534_submit_writer(port, GFP_NOIO);
+               if (status) {
+                       dev_err(&port->dev, "%s: submit failed\n", __func__);
+                       ++error;
+               }
+       }
+
+       if (error)
+               return -EIO;
+
+       return 0;
+}
+
+static struct usb_serial_driver f81534_device = {
+       .driver = {
+                  .owner = THIS_MODULE,
+                  .name = "f81534",
+       },
+       .description =          DRIVER_DESC,
+       .id_table =             f81534_id_table,
+       .open =                 f81534_open,
+       .close =                f81534_close,
+       .write =                f81534_write,
+       .tx_empty =             f81534_tx_empty,
+       .calc_num_ports =       f81534_calc_num_ports,
+       .probe =                f81534_probe,
+       .attach =               f81534_attach,
+       .port_probe =           f81534_port_probe,
+       .dtr_rts =              f81534_dtr_rts,
+       .process_read_urb =     f81534_process_read_urb,
+       .ioctl =                f81534_ioctl,
+       .tiocmget =             f81534_tiocmget,
+       .tiocmset =             f81534_tiocmset,
+       .write_bulk_callback =  f81534_write_usb_callback,
+       .set_termios =          f81534_set_termios,
+       .resume =               f81534_resume,
+};
+
+static struct usb_serial_driver *const serial_drivers[] = {
+       &f81534_device, NULL
+};
+
+module_usb_serial_driver(serial_drivers, f81534_id_table);
+
+MODULE_DEVICE_TABLE(usb, f81534_id_table);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_AUTHOR("Peter Hong <Peter_Hong@fintek.com.tw>");
+MODULE_AUTHOR("Tom Tsai <Tom_Tsai@fintek.com.tw>");
+MODULE_LICENSE("GPL");