// SPDX-License-Identifier: GPL-2.0+
/*
 * F81532/F81534 USB to Serial Ports Bridge
 *
 * F81532 => 2 Serial Ports
 * F81534 => 4 Serial Ports
 *
 * 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_INTERRUPT_ENABLE_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_LINE_STATUS_REG          (0x05 + F81534_UART_BASE_ADDRESS)
#define F81534_MODEM_STATUS_REG         (0x06 + F81534_UART_BASE_ADDRESS)
#define F81534_CLOCK_REG                (0x08 + 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            12

#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_CONF_INIT_GPIO_OFFSET    4
#define F81534_CONF_WORK_GPIO_OFFSET    8
#define F81534_CONF_GPIO_SHUTDOWN       7
#define F81534_CONF_GPIO_RS232          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              2000
#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_PORT_CONF_RS232          0
#define F81534_PORT_CONF_RS485          BIT(0)
#define F81534_PORT_CONF_RS485_INVERT   (BIT(0) | BIT(1))
#define F81534_PORT_CONF_MODE_MASK      GENMASK(1, 0)
#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

/*
 * F81532/534 Clock registers (offset +08h)
 *
 * Bit0:        UART Enable (always on)
 * Bit2-1:      Clock source selector
 *                      00: 1.846MHz.
 *                      01: 18.46MHz.
 *                      10: 24MHz.
 *                      11: 14.77MHz.
 * Bit4:        Auto direction(RTS) control (RTS pin Low when TX)
 * Bit5:        Invert direction(RTS) when Bit4 enabled (RTS pin high when TX)
 */

#define F81534_UART_EN                  BIT(0)
#define F81534_CLK_1_846_MHZ            0
#define F81534_CLK_18_46_MHZ            BIT(1)
#define F81534_CLK_24_MHZ               BIT(2)
#define F81534_CLK_14_77_MHZ            (BIT(1) | BIT(2))
#define F81534_CLK_MASK                 GENMASK(2, 1)
#define F81534_CLK_TX_DELAY_1BIT        BIT(3)
#define F81534_CLK_RS485_MODE           BIT(4)
#define F81534_CLK_RS485_INVERT         BIT(5)

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;
        struct mutex lcr_mutex;
        struct work_struct lsr_work;
        struct usb_serial_port *port;
        unsigned long tx_empty;
        spinlock_t msr_lock;
        u32 baud_base;
        u8 shadow_mcr;
        u8 shadow_lcr;
        u8 shadow_msr;
        u8 shadow_clk;
        u8 phy_num;
};

struct f81534_pin_data {
        const u16 reg_addr;
        const u8 reg_mask;
};

struct f81534_port_out_pin {
        struct f81534_pin_data pin[3];
};

/* Pin output value for M2/M1/M0(SD) */
static const struct f81534_port_out_pin f81534_port_out_pins[] = {
         { { { 0x2ae8, BIT(7) }, { 0x2a90, BIT(5) }, { 0x2a90, BIT(4) } } },
         { { { 0x2ae8, BIT(6) }, { 0x2ae8, BIT(0) }, { 0x2ae8, BIT(3) } } },
         { { { 0x2a90, BIT(0) }, { 0x2ae8, BIT(2) }, { 0x2a80, BIT(6) } } },
         { { { 0x2a90, BIT(3) }, { 0x2a90, BIT(2) }, { 0x2a90, BIT(1) } } },
};

static u32 const baudrate_table[] = { 115200, 921600, 1152000, 1500000 };
static u8 const clock_table[] = { F81534_CLK_1_846_MHZ, F81534_CLK_14_77_MHZ,
                                F81534_CLK_18_46_MHZ, F81534_CLK_24_MHZ };

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 == sizeof(u8)) {
                        status = 0;
                        break;
                }
        }

        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_mask_register(struct usb_serial *serial, u16 reg,
                                        u8 mask, u8 data)
{
        int status;
        u8 tmp;

        status = f81534_get_register(serial, reg, &tmp);
        if (status)
                return status;

        tmp &= ~mask;
        tmp |= (mask & data);

        return f81534_set_register(serial, reg, tmp);
}

static int f81534_set_phy_port_register(struct usb_serial *serial, int phy,
                                        u16 reg, u8 data)
{
        return f81534_set_register(serial, reg + F81534_UART_OFFSET * phy,
                                        data);
}

static int f81534_get_phy_port_register(struct usb_serial *serial, int phy,
                                        u16 reg, u8 *data)
{
        return f81534_get_register(serial, reg + F81534_UART_OFFSET * phy,
                                        data);
}

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)
{
        /* Round to nearest divisor */
        return DIV_ROUND_CLOSEST(clockrate, baudrate);
}

static int f81534_find_clk(u32 baudrate)
{
        int idx;

        for (idx = 0; idx < ARRAY_SIZE(baudrate_table); ++idx) {
                if (baudrate <= baudrate_table[idx] &&
                                baudrate_table[idx] % baudrate == 0)
                        return idx;
        }

        return -EINVAL;
}

static int f81534_set_port_config(struct usb_serial_port *port,
                struct tty_struct *tty, u32 baudrate, u32 old_baudrate, u8 lcr)
{
        struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
        u32 divisor;
        int status;
        int i;
        int idx;
        u8 value;
        u32 baud_list[] = {baudrate, old_baudrate, F81534_DEFAULT_BAUD_RATE};

        for (i = 0; i < ARRAY_SIZE(baud_list); ++i) {
                baudrate = baud_list[i];
                if (baudrate == 0) {
                        tty_encode_baud_rate(tty, 0, 0);
                        return 0;
                }

                idx = f81534_find_clk(baudrate);
                if (idx >= 0) {
                        tty_encode_baud_rate(tty, baudrate, baudrate);
                        break;
                }
        }

        if (idx < 0)
                return -EINVAL;

        port_priv->baud_base = baudrate_table[idx];
        port_priv->shadow_clk &= ~F81534_CLK_MASK;
        port_priv->shadow_clk |= clock_table[idx];

        status = f81534_set_port_register(port, F81534_CLOCK_REG,
                        port_priv->shadow_clk);
        if (status) {
                dev_err(&port->dev, "CLOCK_REG setting failed\n");
                return status;
        }

        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_TRIGGER_8 | UART_FCR_ENABLE_FIFO; /* TL: 8 */

        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, port_priv->baud_base);

        mutex_lock(&port_priv->lcr_mutex);

        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__);
                goto out_unlock;
        }

        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__);
                goto out_unlock;
        }

        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__);
                goto out_unlock;
        }

        value = lcr | (port_priv->shadow_lcr & UART_LCR_SBC);
        status = f81534_set_port_register(port, F81534_LINE_CONTROL_REG,
                                                value);
        if (status) {
                dev_err(&port->dev, "%s: set LCR failed\n", __func__);
                goto out_unlock;
        }

        port_priv->shadow_lcr = value;
out_unlock:
        mutex_unlock(&port_priv->lcr_mutex);

        return status;
}

static int f81534_break_ctl(struct tty_struct *tty, int break_state)
{
        struct usb_serial_port *port = tty->driver_data;
        struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
        int status;

        mutex_lock(&port_priv->lcr_mutex);

        if (break_state)
                port_priv->shadow_lcr |= UART_LCR_SBC;
        else
                port_priv->shadow_lcr &= ~UART_LCR_SBC;

        status = f81534_set_port_register(port, F81534_LINE_CONTROL_REG,
                                        port_priv->shadow_lcr);
        if (status)
                dev_err(&port->dev, "set break failed: %d\n", status);

        mutex_unlock(&port_priv->lcr_mutex);

        return status;
}

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;
}

/*
 * The F81532/534 will not report serial port to USB serial subsystem when
 * H/W DCD/DSR/CTS/RI/RX pin connected to ground.
 *
 * To detect RX pin status, we'll enable MCR interal loopback, disable it and
 * delayed for 60ms. It connected to ground If LSR register report UART_LSR_BI.
 */
static bool f81534_check_port_hw_disabled(struct usb_serial *serial, int phy)
{
        int status;
        u8 old_mcr;
        u8 msr;
        u8 lsr;
        u8 msr_mask;

        msr_mask = UART_MSR_DCD | UART_MSR_RI | UART_MSR_DSR | UART_MSR_CTS;

        status = f81534_get_phy_port_register(serial, phy,
                                F81534_MODEM_STATUS_REG, &msr);
        if (status)
                return false;

        if ((msr & msr_mask) != msr_mask)
                return false;

        status = f81534_set_phy_port_register(serial, phy,
                                F81534_FIFO_CONTROL_REG, UART_FCR_ENABLE_FIFO |
                                UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
        if (status)
                return false;

        status = f81534_get_phy_port_register(serial, phy,
                                F81534_MODEM_CONTROL_REG, &old_mcr);
        if (status)
                return false;

        status = f81534_set_phy_port_register(serial, phy,
                                F81534_MODEM_CONTROL_REG, UART_MCR_LOOP);
        if (status)
                return false;

        status = f81534_set_phy_port_register(serial, phy,
                                F81534_MODEM_CONTROL_REG, 0x0);
        if (status)
                return false;

        msleep(60);

        status = f81534_get_phy_port_register(serial, phy,
                                F81534_LINE_STATUS_REG, &lsr);
        if (status)
                return false;

        status = f81534_set_phy_port_register(serial, phy,
                                F81534_MODEM_CONTROL_REG, old_mcr);
        if (status)
                return false;

        if ((lsr & UART_LSR_BI) == UART_LSR_BI)
                return true;

        return false;
}

/*
 * 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,
                                        struct usb_serial_endpoints *epds)
{
        struct f81534_serial_private *serial_priv;
        struct device *dev = &serial->interface->dev;
        int size_bulk_in = usb_endpoint_maxp(epds->bulk_in[0]);
        int size_bulk_out = usb_endpoint_maxp(epds->bulk_out[0]);
        u8 num_port = 0;
        int index = 0;
        int status;
        int i;

        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;
        }

        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);

        /* 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) {
                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: get custom data failed: %d\n",
                                        __func__, status);
                        return status;
                }

                dev_dbg(&serial->interface->dev,
                                "%s: read config from block: %d\n", __func__,
                                serial_priv->setting_idx);
        } else {
                /* Read default board setting */
                status = f81534_read_flash(serial,
                                F81534_DEF_CONF_ADDRESS_START,
                                sizeof(serial_priv->conf_data),
                                serial_priv->conf_data);
                if (status) {
                        dev_err(&serial->interface->dev,
                                        "%s: read failed: %d\n", __func__,
                                        status);
                        return status;
                }

                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 (f81534_check_port_hw_disabled(serial, i))
                        serial_priv->conf_data[i] |= F81534_PORT_UNAVAILABLE;

                if (serial_priv->conf_data[i] & F81534_PORT_UNAVAILABLE)
                        continue;

                ++num_port;
        }

        if (!num_port) {
                dev_warn(&serial->interface->dev,
                        "no config found, assuming 4 ports\n");
                num_port = 4;           /* Nothing found, oldest version IC */
        }

        /* 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]);
        }

        /*
         * Setup bulk-out endpoint multiplexing. All ports share the same
         * bulk-out endpoint.
         */
        BUILD_BUG_ON(ARRAY_SIZE(epds->bulk_out) < F81534_NUM_PORT);

        for (i = 1; i < num_port; ++i)
                epds->bulk_out[i] = epds->bulk_out[0];

        epds->num_bulk_out = num_port;

        return num_port;
}

static void f81534_set_termios(struct tty_struct *tty,
                               struct usb_serial_port *port,
                               const struct ktermios *old_termios)
{
        u8 new_lcr = 0;
        int status;
        u32 baud;
        u32 old_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;

        new_lcr |= UART_LCR_WLEN(tty_get_char_size(tty->termios.c_cflag));

        baud = tty_get_baud_rate(tty);
        if (!baud)
                return;

        if (old_termios)
                old_baud = tty_termios_baud_rate(old_termios);
        else
                old_baud = F81534_DEFAULT_BAUD_RATE;

        dev_dbg(&port->dev, "%s: baud: %d\n", __func__, baud);

        status = f81534_set_port_config(port, tty, baud, old_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 void f81534_get_serial_info(struct tty_struct *tty, struct serial_struct *ss)
{
        struct usb_serial_port *port = tty->driver_data;
        struct f81534_port_private *port_priv;

        port_priv = usb_get_serial_port_data(port);

        ss->baud_base = port_priv->baud_base;
}

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);
                        }

                        schedule_work(&port_priv->lsr_work);
                }

                if (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 void f81534_lsr_worker(struct work_struct *work)
{
        struct f81534_port_private *port_priv;
        struct usb_serial_port *port;
        int status;
        u8 tmp;

        port_priv = container_of(work, struct f81534_port_private, lsr_work);
        port = port_priv->port;

        status = f81534_get_port_register(port, F81534_LINE_STATUS_REG, &tmp);
        if (status)
                dev_warn(&port->dev, "read LSR failed: %d\n", status);
}

static int f81534_set_port_output_pin(struct usb_serial_port *port)
{
        struct f81534_serial_private *serial_priv;
        struct f81534_port_private *port_priv;
        struct usb_serial *serial;
        const struct f81534_port_out_pin *pins;
        int status;
        int i;
        u8 value;
        u8 idx;

        serial = port->serial;
        serial_priv = usb_get_serial_data(serial);
        port_priv = usb_get_serial_port_data(port);

        idx = F81534_CONF_INIT_GPIO_OFFSET + port_priv->phy_num;
        value = serial_priv->conf_data[idx];
        if (value >= F81534_CONF_GPIO_SHUTDOWN) {
                /*
                 * Newer IC configure will make transceiver in shutdown mode on
                 * initial power on. We need enable it before using UARTs.
                 */
                idx = F81534_CONF_WORK_GPIO_OFFSET + port_priv->phy_num;
                value = serial_priv->conf_data[idx];
                if (value >= F81534_CONF_GPIO_SHUTDOWN)
                        value = F81534_CONF_GPIO_RS232;
        }

        pins = &f81534_port_out_pins[port_priv->phy_num];

        for (i = 0; i < ARRAY_SIZE(pins->pin); ++i) {
                status = f81534_set_mask_register(serial,
                                pins->pin[i].reg_addr, pins->pin[i].reg_mask,
                                value & BIT(i) ? pins->pin[i].reg_mask : 0);
                if (status)
                        return status;
        }

        dev_dbg(&port->dev, "Output pin (M0/M1/M2): %d\n", value);
        return 0;
}

static int f81534_port_probe(struct usb_serial_port *port)
{
        struct f81534_serial_private *serial_priv;
        struct f81534_port_private *port_priv;
        int ret;
        u8 value;

        serial_priv = usb_get_serial_data(port->serial);
        port_priv = devm_kzalloc(&port->dev, sizeof(*port_priv), GFP_KERNEL);
        if (!port_priv)
                return -ENOMEM;

        /*
         * We'll make tx frame error when baud rate from 384~500kps. So we'll
         * delay all tx data frame with 1bit.
         */
        port_priv->shadow_clk = F81534_UART_EN | F81534_CLK_TX_DELAY_1BIT;
        spin_lock_init(&port_priv->msr_lock);
        mutex_init(&port_priv->mcr_mutex);
        mutex_init(&port_priv->lcr_mutex);
        INIT_WORK(&port_priv->lsr_work, f81534_lsr_worker);

        /* Assign logic-to-phy mapping */
        ret = f81534_logic_to_phy_port(port->serial, port);
        if (ret < 0)
                return ret;

        port_priv->phy_num = ret;
        port_priv->port = port;
        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);

        /*
         * The F81532/534 will hang-up when enable LSR interrupt in IER and
         * occur data overrun. So we'll disable the LSR interrupt in probe()
         * and submit the LSR worker to clear LSR state when reported LSR error
         * bit with bulk-in data in f81534_process_per_serial_block().
         */
        ret = f81534_set_port_register(port, F81534_INTERRUPT_ENABLE_REG,
                        UART_IER_RDI | UART_IER_THRI | UART_IER_MSI);
        if (ret)
                return ret;

        value = serial_priv->conf_data[port_priv->phy_num];
        switch (value & F81534_PORT_CONF_MODE_MASK) {
        case F81534_PORT_CONF_RS485_INVERT:
                port_priv->shadow_clk |= F81534_CLK_RS485_MODE |
                                        F81534_CLK_RS485_INVERT;
                dev_dbg(&port->dev, "RS485 invert mode\n");
                break;
        case F81534_PORT_CONF_RS485:
                port_priv->shadow_clk |= F81534_CLK_RS485_MODE;
                dev_dbg(&port->dev, "RS485 mode\n");
                break;

        default:
        case F81534_PORT_CONF_RS232:
                dev_dbg(&port->dev, "RS232 mode\n");
                break;
        }

        return f81534_set_port_output_pin(port);
}

static void f81534_port_remove(struct usb_serial_port *port)
{
        struct f81534_port_private *port_priv = usb_get_serial_port_data(port);

        flush_work(&port_priv->lsr_work);
}

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 = {
                   .name = "f81534",
        },
        .description =          DRIVER_DESC,
        .id_table =             f81534_id_table,
        .num_bulk_in =          1,
        .num_bulk_out =         1,
        .open =                 f81534_open,
        .close =                f81534_close,
        .write =                f81534_write,
        .tx_empty =             f81534_tx_empty,
        .calc_num_ports =       f81534_calc_num_ports,
        .port_probe =           f81534_port_probe,
        .port_remove =          f81534_port_remove,
        .break_ctl =            f81534_break_ctl,
        .dtr_rts =              f81534_dtr_rts,
        .process_read_urb =     f81534_process_read_urb,
        .get_serial =           f81534_get_serial_info,
        .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");