/*
 * Silicon Laboratories CP210x USB to RS232 serial adaptor driver
 *
 * Copyright (C) 2005 Craig Shelley (craig@microtron.org.uk)
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License version
 *      2 as published by the Free Software Foundation.
 *
 * Support to set flow control line levels using TIOCMGET and TIOCMSET
 * thanks to Karl Hiramoto karl@hiramoto.org. RTSCTS hardware flow
 * control thanks to Munir Nassar nassarmu@real-time.com
 *
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/usb.h>
#include <linux/uaccess.h>
#include <linux/usb/serial.h>

#define DRIVER_DESC "Silicon Labs CP210x RS232 serial adaptor driver"

/*
 * Function Prototypes
 */
static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *);
static void cp210x_close(struct usb_serial_port *);
static void cp210x_get_termios(struct tty_struct *, struct usb_serial_port *);
static void cp210x_get_termios_port(struct usb_serial_port *port,
        unsigned int *cflagp, unsigned int *baudp);
static void cp210x_change_speed(struct tty_struct *, struct usb_serial_port *,
                                                        struct ktermios *);
static void cp210x_set_termios(struct tty_struct *, struct usb_serial_port *,
                                                        struct ktermios*);
static bool cp210x_tx_empty(struct usb_serial_port *port);
static int cp210x_tiocmget(struct tty_struct *);
static int cp210x_tiocmset(struct tty_struct *, unsigned int, unsigned int);
static int cp210x_tiocmset_port(struct usb_serial_port *port,
                unsigned int, unsigned int);
static void cp210x_break_ctl(struct tty_struct *, int);
static int cp210x_port_probe(struct usb_serial_port *);
static int cp210x_port_remove(struct usb_serial_port *);
static void cp210x_dtr_rts(struct usb_serial_port *p, int on);

static const struct usb_device_id id_table[] = {
        { USB_DEVICE(0x045B, 0x0053) }, /* Renesas RX610 RX-Stick */
        { USB_DEVICE(0x0471, 0x066A) }, /* AKTAKOM ACE-1001 cable */
        { USB_DEVICE(0x0489, 0xE000) }, /* Pirelli Broadband S.p.A, DP-L10 SIP/GSM Mobile */
        { USB_DEVICE(0x0489, 0xE003) }, /* Pirelli Broadband S.p.A, DP-L10 SIP/GSM Mobile */
        { USB_DEVICE(0x0745, 0x1000) }, /* CipherLab USB CCD Barcode Scanner 1000 */
        { USB_DEVICE(0x0846, 0x1100) }, /* NetGear Managed Switch M4100 series, M5300 series, M7100 series */
        { USB_DEVICE(0x08e6, 0x5501) }, /* Gemalto Prox-PU/CU contactless smartcard reader */
        { USB_DEVICE(0x08FD, 0x000A) }, /* Digianswer A/S , ZigBee/802.15.4 MAC Device */
        { USB_DEVICE(0x0908, 0x01FF) }, /* Siemens RUGGEDCOM USB Serial Console */
        { USB_DEVICE(0x0BED, 0x1100) }, /* MEI (TM) Cashflow-SC Bill/Voucher Acceptor */
        { USB_DEVICE(0x0BED, 0x1101) }, /* MEI series 2000 Combo Acceptor */
        { USB_DEVICE(0x0FCF, 0x1003) }, /* Dynastream ANT development board */
        { USB_DEVICE(0x0FCF, 0x1004) }, /* Dynastream ANT2USB */
        { USB_DEVICE(0x0FCF, 0x1006) }, /* Dynastream ANT development board */
        { USB_DEVICE(0x0FDE, 0xCA05) }, /* OWL Wireless Electricity Monitor CM-160 */
        { USB_DEVICE(0x10A6, 0xAA26) }, /* Knock-off DCU-11 cable */
        { USB_DEVICE(0x10AB, 0x10C5) }, /* Siemens MC60 Cable */
        { USB_DEVICE(0x10B5, 0xAC70) }, /* Nokia CA-42 USB */
        { USB_DEVICE(0x10C4, 0x0F91) }, /* Vstabi */
        { USB_DEVICE(0x10C4, 0x1101) }, /* Arkham Technology DS101 Bus Monitor */
        { USB_DEVICE(0x10C4, 0x1601) }, /* Arkham Technology DS101 Adapter */
        { USB_DEVICE(0x10C4, 0x800A) }, /* SPORTident BSM7-D-USB main station */
        { USB_DEVICE(0x10C4, 0x803B) }, /* Pololu USB-serial converter */
        { USB_DEVICE(0x10C4, 0x8044) }, /* Cygnal Debug Adapter */
        { USB_DEVICE(0x10C4, 0x804E) }, /* Software Bisque Paramount ME build-in converter */
        { USB_DEVICE(0x10C4, 0x8053) }, /* Enfora EDG1228 */
        { USB_DEVICE(0x10C4, 0x8054) }, /* Enfora GSM2228 */
        { USB_DEVICE(0x10C4, 0x8066) }, /* Argussoft In-System Programmer */
        { USB_DEVICE(0x10C4, 0x806F) }, /* IMS USB to RS422 Converter Cable */
        { USB_DEVICE(0x10C4, 0x807A) }, /* Crumb128 board */
        { USB_DEVICE(0x10C4, 0x80C4) }, /* Cygnal Integrated Products, Inc., Optris infrared thermometer */
        { USB_DEVICE(0x10C4, 0x80CA) }, /* Degree Controls Inc */
        { USB_DEVICE(0x10C4, 0x80DD) }, /* Tracient RFID */
        { USB_DEVICE(0x10C4, 0x80F6) }, /* Suunto sports instrument */
        { USB_DEVICE(0x10C4, 0x8115) }, /* Arygon NFC/Mifare Reader */
        { USB_DEVICE(0x10C4, 0x813D) }, /* Burnside Telecom Deskmobile */
        { USB_DEVICE(0x10C4, 0x813F) }, /* Tams Master Easy Control */
        { USB_DEVICE(0x10C4, 0x814A) }, /* West Mountain Radio RIGblaster P&P */
        { USB_DEVICE(0x10C4, 0x814B) }, /* West Mountain Radio RIGtalk */
        { USB_DEVICE(0x2405, 0x0003) }, /* West Mountain Radio RIGblaster Advantage */
        { USB_DEVICE(0x10C4, 0x8156) }, /* B&G H3000 link cable */
        { USB_DEVICE(0x10C4, 0x815E) }, /* Helicomm IP-Link 1220-DVM */
        { USB_DEVICE(0x10C4, 0x815F) }, /* Timewave HamLinkUSB */
        { USB_DEVICE(0x10C4, 0x818B) }, /* AVIT Research USB to TTL */
        { USB_DEVICE(0x10C4, 0x819F) }, /* MJS USB Toslink Switcher */
        { USB_DEVICE(0x10C4, 0x81A6) }, /* ThinkOptics WavIt */
        { USB_DEVICE(0x10C4, 0x81A9) }, /* Multiplex RC Interface */
        { USB_DEVICE(0x10C4, 0x81AC) }, /* MSD Dash Hawk */
        { USB_DEVICE(0x10C4, 0x81AD) }, /* INSYS USB Modem */
        { USB_DEVICE(0x10C4, 0x81C8) }, /* Lipowsky Industrie Elektronik GmbH, Baby-JTAG */
        { USB_DEVICE(0x10C4, 0x81D7) }, /* IAI Corp. RCB-CV-USB USB to RS485 Adaptor */
        { USB_DEVICE(0x10C4, 0x81E2) }, /* Lipowsky Industrie Elektronik GmbH, Baby-LIN */
        { USB_DEVICE(0x10C4, 0x81E7) }, /* Aerocomm Radio */
        { USB_DEVICE(0x10C4, 0x81E8) }, /* Zephyr Bioharness */
        { USB_DEVICE(0x10C4, 0x81F2) }, /* C1007 HF band RFID controller */
        { USB_DEVICE(0x10C4, 0x8218) }, /* Lipowsky Industrie Elektronik GmbH, HARP-1 */
        { USB_DEVICE(0x10C4, 0x822B) }, /* Modem EDGE(GSM) Comander 2 */
        { USB_DEVICE(0x10C4, 0x826B) }, /* Cygnal Integrated Products, Inc., Fasttrax GPS demonstration module */
        { USB_DEVICE(0x10C4, 0x8281) }, /* Nanotec Plug & Drive */
        { USB_DEVICE(0x10C4, 0x8293) }, /* Telegesis ETRX2USB */
        { USB_DEVICE(0x10C4, 0x82F4) }, /* Starizona MicroTouch */
        { USB_DEVICE(0x10C4, 0x82F9) }, /* Procyon AVS */
        { USB_DEVICE(0x10C4, 0x8341) }, /* Siemens MC35PU GPRS Modem */
        { USB_DEVICE(0x10C4, 0x8382) }, /* Cygnal Integrated Products, Inc. */
        { USB_DEVICE(0x10C4, 0x83A8) }, /* Amber Wireless AMB2560 */
        { USB_DEVICE(0x10C4, 0x83D8) }, /* DekTec DTA Plus VHF/UHF Booster/Attenuator */
        { USB_DEVICE(0x10C4, 0x8411) }, /* Kyocera GPS Module */
        { USB_DEVICE(0x10C4, 0x8418) }, /* IRZ Automation Teleport SG-10 GSM/GPRS Modem */
        { USB_DEVICE(0x10C4, 0x846E) }, /* BEI USB Sensor Interface (VCP) */
        { USB_DEVICE(0x10C4, 0x8477) }, /* Balluff RFID */
        { USB_DEVICE(0x10C4, 0x84B6) }, /* Starizona Hyperion */
        { USB_DEVICE(0x10C4, 0x85EA) }, /* AC-Services IBUS-IF */
        { USB_DEVICE(0x10C4, 0x85EB) }, /* AC-Services CIS-IBUS */
        { USB_DEVICE(0x10C4, 0x85F8) }, /* Virtenio Preon32 */
        { USB_DEVICE(0x10C4, 0x8664) }, /* AC-Services CAN-IF */
        { USB_DEVICE(0x10C4, 0x8665) }, /* AC-Services OBD-IF */
        { USB_DEVICE(0x10C4, 0x8856) }, /* CEL EM357 ZigBee USB Stick - LR */
        { USB_DEVICE(0x10C4, 0x8857) }, /* CEL EM357 ZigBee USB Stick */
        { USB_DEVICE(0x10C4, 0x88A4) }, /* MMB Networks ZigBee USB Device */
        { USB_DEVICE(0x10C4, 0x88A5) }, /* Planet Innovation Ingeni ZigBee USB Device */
        { USB_DEVICE(0x10C4, 0x8946) }, /* Ketra N1 Wireless Interface */
        { USB_DEVICE(0x10C4, 0x8977) }, /* CEL MeshWorks DevKit Device */
        { USB_DEVICE(0x10C4, 0x8998) }, /* KCF Technologies PRN */
        { USB_DEVICE(0x10C4, 0x8A2A) }, /* HubZ dual ZigBee and Z-Wave dongle */
        { USB_DEVICE(0x10C4, 0xEA60) }, /* Silicon Labs factory default */
        { USB_DEVICE(0x10C4, 0xEA61) }, /* Silicon Labs factory default */
        { USB_DEVICE(0x10C4, 0xEA70) }, /* Silicon Labs factory default */
        { USB_DEVICE(0x10C4, 0xEA71) }, /* Infinity GPS-MIC-1 Radio Monophone */
        { USB_DEVICE(0x10C4, 0xF001) }, /* Elan Digital Systems USBscope50 */
        { USB_DEVICE(0x10C4, 0xF002) }, /* Elan Digital Systems USBwave12 */
        { USB_DEVICE(0x10C4, 0xF003) }, /* Elan Digital Systems USBpulse100 */
        { USB_DEVICE(0x10C4, 0xF004) }, /* Elan Digital Systems USBcount50 */
        { USB_DEVICE(0x10C5, 0xEA61) }, /* Silicon Labs MobiData GPRS USB Modem */
        { USB_DEVICE(0x10CE, 0xEA6A) }, /* Silicon Labs MobiData GPRS USB Modem 100EU */
        { USB_DEVICE(0x12B8, 0xEC60) }, /* Link G4 ECU */
        { USB_DEVICE(0x12B8, 0xEC62) }, /* Link G4+ ECU */
        { USB_DEVICE(0x13AD, 0x9999) }, /* Baltech card reader */
        { USB_DEVICE(0x1555, 0x0004) }, /* Owen AC4 USB-RS485 Converter */
        { USB_DEVICE(0x166A, 0x0201) }, /* Clipsal 5500PACA C-Bus Pascal Automation Controller */
        { USB_DEVICE(0x166A, 0x0301) }, /* Clipsal 5800PC C-Bus Wireless PC Interface */
        { USB_DEVICE(0x166A, 0x0303) }, /* Clipsal 5500PCU C-Bus USB interface */
        { USB_DEVICE(0x166A, 0x0304) }, /* Clipsal 5000CT2 C-Bus Black and White Touchscreen */
        { USB_DEVICE(0x166A, 0x0305) }, /* Clipsal C-5000CT2 C-Bus Spectrum Colour Touchscreen */
        { USB_DEVICE(0x166A, 0x0401) }, /* Clipsal L51xx C-Bus Architectural Dimmer */
        { USB_DEVICE(0x166A, 0x0101) }, /* Clipsal 5560884 C-Bus Multi-room Audio Matrix Switcher */
        { USB_DEVICE(0x16C0, 0x09B0) }, /* Lunatico Seletek */
        { USB_DEVICE(0x16C0, 0x09B1) }, /* Lunatico Seletek */
        { USB_DEVICE(0x16D6, 0x0001) }, /* Jablotron serial interface */
        { USB_DEVICE(0x16DC, 0x0010) }, /* W-IE-NE-R Plein & Baus GmbH PL512 Power Supply */
        { USB_DEVICE(0x16DC, 0x0011) }, /* W-IE-NE-R Plein & Baus GmbH RCM Remote Control for MARATON Power Supply */
        { USB_DEVICE(0x16DC, 0x0012) }, /* W-IE-NE-R Plein & Baus GmbH MPOD Multi Channel Power Supply */
        { USB_DEVICE(0x16DC, 0x0015) }, /* W-IE-NE-R Plein & Baus GmbH CML Control, Monitoring and Data Logger */
        { USB_DEVICE(0x17A8, 0x0001) }, /* Kamstrup Optical Eye/3-wire */
        { USB_DEVICE(0x17A8, 0x0005) }, /* Kamstrup M-Bus Master MultiPort 250D */
        { USB_DEVICE(0x17F4, 0xAAAA) }, /* Wavesense Jazz blood glucose meter */
        { USB_DEVICE(0x1843, 0x0200) }, /* Vaisala USB Instrument Cable */
        { USB_DEVICE(0x18EF, 0xE00F) }, /* ELV USB-I2C-Interface */
        { USB_DEVICE(0x18EF, 0xE025) }, /* ELV Marble Sound Board 1 */
        { USB_DEVICE(0x1901, 0x0190) }, /* GE B850 CP2105 Recorder interface */
        { USB_DEVICE(0x1901, 0x0193) }, /* GE B650 CP2104 PMC interface */
        { USB_DEVICE(0x1901, 0x0194) }, /* GE Healthcare Remote Alarm Box */
        { USB_DEVICE(0x19CF, 0x3000) }, /* Parrot NMEA GPS Flight Recorder */
        { USB_DEVICE(0x1ADB, 0x0001) }, /* Schweitzer Engineering C662 Cable */
        { USB_DEVICE(0x1B1C, 0x1C00) }, /* Corsair USB Dongle */
        { USB_DEVICE(0x1BA4, 0x0002) }, /* Silicon Labs 358x factory default */
        { USB_DEVICE(0x1BE3, 0x07A6) }, /* WAGO 750-923 USB Service Cable */
        { USB_DEVICE(0x1D6F, 0x0010) }, /* Seluxit ApS RF Dongle */
        { USB_DEVICE(0x1E29, 0x0102) }, /* Festo CPX-USB */
        { USB_DEVICE(0x1E29, 0x0501) }, /* Festo CMSP */
        { USB_DEVICE(0x1FB9, 0x0100) }, /* Lake Shore Model 121 Current Source */
        { USB_DEVICE(0x1FB9, 0x0200) }, /* Lake Shore Model 218A Temperature Monitor */
        { USB_DEVICE(0x1FB9, 0x0201) }, /* Lake Shore Model 219 Temperature Monitor */
        { USB_DEVICE(0x1FB9, 0x0202) }, /* Lake Shore Model 233 Temperature Transmitter */
        { USB_DEVICE(0x1FB9, 0x0203) }, /* Lake Shore Model 235 Temperature Transmitter */
        { USB_DEVICE(0x1FB9, 0x0300) }, /* Lake Shore Model 335 Temperature Controller */
        { USB_DEVICE(0x1FB9, 0x0301) }, /* Lake Shore Model 336 Temperature Controller */
        { USB_DEVICE(0x1FB9, 0x0302) }, /* Lake Shore Model 350 Temperature Controller */
        { USB_DEVICE(0x1FB9, 0x0303) }, /* Lake Shore Model 371 AC Bridge */
        { USB_DEVICE(0x1FB9, 0x0400) }, /* Lake Shore Model 411 Handheld Gaussmeter */
        { USB_DEVICE(0x1FB9, 0x0401) }, /* Lake Shore Model 425 Gaussmeter */
        { USB_DEVICE(0x1FB9, 0x0402) }, /* Lake Shore Model 455A Gaussmeter */
        { USB_DEVICE(0x1FB9, 0x0403) }, /* Lake Shore Model 475A Gaussmeter */
        { USB_DEVICE(0x1FB9, 0x0404) }, /* Lake Shore Model 465 Three Axis Gaussmeter */
        { USB_DEVICE(0x1FB9, 0x0600) }, /* Lake Shore Model 625A Superconducting MPS */
        { USB_DEVICE(0x1FB9, 0x0601) }, /* Lake Shore Model 642A Magnet Power Supply */
        { USB_DEVICE(0x1FB9, 0x0602) }, /* Lake Shore Model 648 Magnet Power Supply */
        { USB_DEVICE(0x1FB9, 0x0700) }, /* Lake Shore Model 737 VSM Controller */
        { USB_DEVICE(0x1FB9, 0x0701) }, /* Lake Shore Model 776 Hall Matrix */
        { USB_DEVICE(0x2626, 0xEA60) }, /* Aruba Networks 7xxx USB Serial Console */
        { USB_DEVICE(0x3195, 0xF190) }, /* Link Instruments MSO-19 */
        { USB_DEVICE(0x3195, 0xF280) }, /* Link Instruments MSO-28 */
        { USB_DEVICE(0x3195, 0xF281) }, /* Link Instruments MSO-28 */
        { USB_DEVICE(0x413C, 0x9500) }, /* DW700 GPS USB interface */
        { } /* Terminating Entry */
};

MODULE_DEVICE_TABLE(usb, id_table);

struct cp210x_port_private {
        __u8                    bInterfaceNumber;
        bool                    has_swapped_line_ctl;
};

static struct usb_serial_driver cp210x_device = {
        .driver = {
                .owner =        THIS_MODULE,
                .name =         "cp210x",
        },
        .id_table               = id_table,
        .num_ports              = 1,
        .bulk_in_size           = 256,
        .bulk_out_size          = 256,
        .open                   = cp210x_open,
        .close                  = cp210x_close,
        .break_ctl              = cp210x_break_ctl,
        .set_termios            = cp210x_set_termios,
        .tx_empty               = cp210x_tx_empty,
        .tiocmget               = cp210x_tiocmget,
        .tiocmset               = cp210x_tiocmset,
        .port_probe             = cp210x_port_probe,
        .port_remove            = cp210x_port_remove,
        .dtr_rts                = cp210x_dtr_rts
};

static struct usb_serial_driver * const serial_drivers[] = {
        &cp210x_device, NULL
};

/* Config request types */
#define REQTYPE_HOST_TO_INTERFACE       0x41
#define REQTYPE_INTERFACE_TO_HOST       0xc1
#define REQTYPE_HOST_TO_DEVICE  0x40
#define REQTYPE_DEVICE_TO_HOST  0xc0

/* Config request codes */
#define CP210X_IFC_ENABLE       0x00
#define CP210X_SET_BAUDDIV      0x01
#define CP210X_GET_BAUDDIV      0x02
#define CP210X_SET_LINE_CTL     0x03
#define CP210X_GET_LINE_CTL     0x04
#define CP210X_SET_BREAK        0x05
#define CP210X_IMM_CHAR         0x06
#define CP210X_SET_MHS          0x07
#define CP210X_GET_MDMSTS       0x08
#define CP210X_SET_XON          0x09
#define CP210X_SET_XOFF         0x0A
#define CP210X_SET_EVENTMASK    0x0B
#define CP210X_GET_EVENTMASK    0x0C
#define CP210X_SET_CHAR         0x0D
#define CP210X_GET_CHARS        0x0E
#define CP210X_GET_PROPS        0x0F
#define CP210X_GET_COMM_STATUS  0x10
#define CP210X_RESET            0x11
#define CP210X_PURGE            0x12
#define CP210X_SET_FLOW         0x13
#define CP210X_GET_FLOW         0x14
#define CP210X_EMBED_EVENTS     0x15
#define CP210X_GET_EVENTSTATE   0x16
#define CP210X_SET_CHARS        0x19
#define CP210X_GET_BAUDRATE     0x1D
#define CP210X_SET_BAUDRATE     0x1E

/* CP210X_IFC_ENABLE */
#define UART_ENABLE             0x0001
#define UART_DISABLE            0x0000

/* CP210X_(SET|GET)_BAUDDIV */
#define BAUD_RATE_GEN_FREQ      0x384000

/* CP210X_(SET|GET)_LINE_CTL */
#define BITS_DATA_MASK          0X0f00
#define BITS_DATA_5             0X0500
#define BITS_DATA_6             0X0600
#define BITS_DATA_7             0X0700
#define BITS_DATA_8             0X0800
#define BITS_DATA_9             0X0900

#define BITS_PARITY_MASK        0x00f0
#define BITS_PARITY_NONE        0x0000
#define BITS_PARITY_ODD         0x0010
#define BITS_PARITY_EVEN        0x0020
#define BITS_PARITY_MARK        0x0030
#define BITS_PARITY_SPACE       0x0040

#define BITS_STOP_MASK          0x000f
#define BITS_STOP_1             0x0000
#define BITS_STOP_1_5           0x0001
#define BITS_STOP_2             0x0002

/* CP210X_SET_BREAK */
#define BREAK_ON                0x0001
#define BREAK_OFF               0x0000

/* CP210X_(SET_MHS|GET_MDMSTS) */
#define CONTROL_DTR             0x0001
#define CONTROL_RTS             0x0002
#define CONTROL_CTS             0x0010
#define CONTROL_DSR             0x0020
#define CONTROL_RING            0x0040
#define CONTROL_DCD             0x0080
#define CONTROL_WRITE_DTR       0x0100
#define CONTROL_WRITE_RTS       0x0200

/* CP210X_GET_COMM_STATUS returns these 0x13 bytes */
struct cp210x_comm_status {
        __le32   ulErrors;
        __le32   ulHoldReasons;
        __le32   ulAmountInInQueue;
        __le32   ulAmountInOutQueue;
        u8       bEofReceived;
        u8       bWaitForImmediate;
        u8       bReserved;
} __packed;

/*
 * CP210X_PURGE - 16 bits passed in wValue of USB request.
 * SiLabs app note AN571 gives a strange description of the 4 bits:
 * bit 0 or bit 2 clears the transmit queue and 1 or 3 receive.
 * writing 1 to all, however, purges cp2108 well enough to avoid the hang.
 */
#define PURGE_ALL               0x000f

/*
 * Reads a variable-sized block of CP210X_ registers, identified by req.
 * Returns data into buf in native USB byte order.
 */
static int cp210x_read_reg_block(struct usb_serial_port *port, u8 req,
                void *buf, int bufsize)
{
        struct usb_serial *serial = port->serial;
        struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
        void *dmabuf;
        int result;

        dmabuf = kmalloc(bufsize, GFP_KERNEL);
        if (!dmabuf) {
                /*
                 * FIXME Some callers don't bother to check for error,
                 * at least give them consistent junk until they are fixed
                 */
                memset(buf, 0, bufsize);
                return -ENOMEM;
        }

        result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
                        req, REQTYPE_INTERFACE_TO_HOST, 0,
                        port_priv->bInterfaceNumber, dmabuf, bufsize,
                        USB_CTRL_SET_TIMEOUT);
        if (result == bufsize) {
                memcpy(buf, dmabuf, bufsize);
                result = 0;
        } else {
                dev_err(&port->dev, "failed get req 0x%x size %d status: %d\n",
                                req, bufsize, result);
                if (result >= 0)
                        result = -EPROTO;

                /*
                 * FIXME Some callers don't bother to check for error,
                 * at least give them consistent junk until they are fixed
                 */
                memset(buf, 0, bufsize);
        }

        kfree(dmabuf);

        return result;
}

/*
 * Reads any 32-bit CP210X_ register identified by req.
 */
static int cp210x_read_u32_reg(struct usb_serial_port *port, u8 req, u32 *val)
{
        __le32 le32_val;
        int err;

        err = cp210x_read_reg_block(port, req, &le32_val, sizeof(le32_val));
        if (err) {
                /*
                 * FIXME Some callers don't bother to check for error,
                 * at least give them consistent junk until they are fixed
                 */
                *val = 0;
                return err;
        }

        *val = le32_to_cpu(le32_val);

        return 0;
}

/*
 * Reads any 16-bit CP210X_ register identified by req.
 */
static int cp210x_read_u16_reg(struct usb_serial_port *port, u8 req, u16 *val)
{
        __le16 le16_val;
        int err;

        err = cp210x_read_reg_block(port, req, &le16_val, sizeof(le16_val));
        if (err)
                return err;

        *val = le16_to_cpu(le16_val);

        return 0;
}

/*
 * Reads any 8-bit CP210X_ register identified by req.
 */
static int cp210x_read_u8_reg(struct usb_serial_port *port, u8 req, u8 *val)
{
        return cp210x_read_reg_block(port, req, val, sizeof(*val));
}

/*
 * Writes any 16-bit CP210X_ register (req) whose value is passed
 * entirely in the wValue field of the USB request.
 */
static int cp210x_write_u16_reg(struct usb_serial_port *port, u8 req, u16 val)
{
        struct usb_serial *serial = port->serial;
        struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
        int result;

        result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                        req, REQTYPE_HOST_TO_INTERFACE, val,
                        port_priv->bInterfaceNumber, NULL, 0,
                        USB_CTRL_SET_TIMEOUT);
        if (result < 0) {
                dev_err(&port->dev, "failed set request 0x%x status: %d\n",
                                req, result);
        }

        return result;
}

/*
 * Writes a variable-sized block of CP210X_ registers, identified by req.
 * Data in buf must be in native USB byte order.
 */
static int cp210x_write_reg_block(struct usb_serial_port *port, u8 req,
                void *buf, int bufsize)
{
        struct usb_serial *serial = port->serial;
        struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
        void *dmabuf;
        int result;

        dmabuf = kmalloc(bufsize, GFP_KERNEL);
        if (!dmabuf)
                return -ENOMEM;

        memcpy(dmabuf, buf, bufsize);

        result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                        req, REQTYPE_HOST_TO_INTERFACE, 0,
                        port_priv->bInterfaceNumber, dmabuf, bufsize,
                        USB_CTRL_SET_TIMEOUT);

        kfree(dmabuf);

        if (result == bufsize) {
                result = 0;
        } else {
                dev_err(&port->dev, "failed set req 0x%x size %d status: %d\n",
                                req, bufsize, result);
                if (result >= 0)
                        result = -EPROTO;
        }

        return result;
}

/*
 * Writes any 32-bit CP210X_ register identified by req.
 */
static int cp210x_write_u32_reg(struct usb_serial_port *port, u8 req, u32 val)
{
        __le32 le32_val;

        le32_val = cpu_to_le32(val);

        return cp210x_write_reg_block(port, req, &le32_val, sizeof(le32_val));
}

/*
 * Detect CP2108 GET_LINE_CTL bug and activate workaround.
 * Write a known good value 0x800, read it back.
 * If it comes back swapped the bug is detected.
 * Preserve the original register value.
 */
static int cp210x_detect_swapped_line_ctl(struct usb_serial_port *port)
{
        struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
        u16 line_ctl_save;
        u16 line_ctl_test;
        int err;

        err = cp210x_read_u16_reg(port, CP210X_GET_LINE_CTL, &line_ctl_save);
        if (err)
                return err;

        err = cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, 0x800);
        if (err)
                return err;

        err = cp210x_read_u16_reg(port, CP210X_GET_LINE_CTL, &line_ctl_test);
        if (err)
                return err;

        if (line_ctl_test == 8) {
                port_priv->has_swapped_line_ctl = true;
                line_ctl_save = swab16(line_ctl_save);
        }

        return cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, line_ctl_save);
}

/*
 * Must always be called instead of cp210x_read_u16_reg(CP210X_GET_LINE_CTL)
 * to workaround cp2108 bug and get correct value.
 */
static int cp210x_get_line_ctl(struct usb_serial_port *port, u16 *ctl)
{
        struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
        int err;

        err = cp210x_read_u16_reg(port, CP210X_GET_LINE_CTL, ctl);
        if (err)
                return err;

        /* Workaround swapped bytes in 16-bit value from CP210X_GET_LINE_CTL */
        if (port_priv->has_swapped_line_ctl)
                *ctl = swab16(*ctl);

        return 0;
}

/*
 * cp210x_quantise_baudrate
 * Quantises the baud rate as per AN205 Table 1
 */
static unsigned int cp210x_quantise_baudrate(unsigned int baud)
{
        if (baud <= 300)
                baud = 300;
        else if (baud <= 600)      baud = 600;
        else if (baud <= 1200)     baud = 1200;
        else if (baud <= 1800)     baud = 1800;
        else if (baud <= 2400)     baud = 2400;
        else if (baud <= 4000)     baud = 4000;
        else if (baud <= 4803)     baud = 4800;
        else if (baud <= 7207)     baud = 7200;
        else if (baud <= 9612)     baud = 9600;
        else if (baud <= 14428)    baud = 14400;
        else if (baud <= 16062)    baud = 16000;
        else if (baud <= 19250)    baud = 19200;
        else if (baud <= 28912)    baud = 28800;
        else if (baud <= 38601)    baud = 38400;
        else if (baud <= 51558)    baud = 51200;
        else if (baud <= 56280)    baud = 56000;
        else if (baud <= 58053)    baud = 57600;
        else if (baud <= 64111)    baud = 64000;
        else if (baud <= 77608)    baud = 76800;
        else if (baud <= 117028)   baud = 115200;
        else if (baud <= 129347)   baud = 128000;
        else if (baud <= 156868)   baud = 153600;
        else if (baud <= 237832)   baud = 230400;
        else if (baud <= 254234)   baud = 250000;
        else if (baud <= 273066)   baud = 256000;
        else if (baud <= 491520)   baud = 460800;
        else if (baud <= 567138)   baud = 500000;
        else if (baud <= 670254)   baud = 576000;
        else if (baud < 1000000)
                baud = 921600;
        else if (baud > 2000000)
                baud = 2000000;
        return baud;
}

static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *port)
{
        int result;

        result = cp210x_write_u16_reg(port, CP210X_IFC_ENABLE, UART_ENABLE);
        if (result) {
                dev_err(&port->dev, "%s - Unable to enable UART\n", __func__);
                return result;
        }

        /* Configure the termios structure */
        cp210x_get_termios(tty, port);

        /* The baud rate must be initialised on cp2104 */
        if (tty)
                cp210x_change_speed(tty, port, NULL);

        return usb_serial_generic_open(tty, port);
}

static void cp210x_close(struct usb_serial_port *port)
{
        usb_serial_generic_close(port);

        /* Clear both queues; cp2108 needs this to avoid an occasional hang */
        cp210x_write_u16_reg(port, CP210X_PURGE, PURGE_ALL);

        cp210x_write_u16_reg(port, CP210X_IFC_ENABLE, UART_DISABLE);
}

/*
 * Read how many bytes are waiting in the TX queue.
 */
static int cp210x_get_tx_queue_byte_count(struct usb_serial_port *port,
                u32 *count)
{
        struct usb_serial *serial = port->serial;
        struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
        struct cp210x_comm_status *sts;
        int result;

        sts = kmalloc(sizeof(*sts), GFP_KERNEL);
        if (!sts)
                return -ENOMEM;

        result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
                        CP210X_GET_COMM_STATUS, REQTYPE_INTERFACE_TO_HOST,
                        0, port_priv->bInterfaceNumber, sts, sizeof(*sts),
                        USB_CTRL_GET_TIMEOUT);
        if (result == sizeof(*sts)) {
                *count = le32_to_cpu(sts->ulAmountInOutQueue);
                result = 0;
        } else {
                dev_err(&port->dev, "failed to get comm status: %d\n", result);
                if (result >= 0)
                        result = -EPROTO;
        }

        kfree(sts);

        return result;
}

static bool cp210x_tx_empty(struct usb_serial_port *port)
{
        int err;
        u32 count;

        err = cp210x_get_tx_queue_byte_count(port, &count);
        if (err)
                return true;

        return !count;
}

/*
 * cp210x_get_termios
 * Reads the baud rate, data bits, parity, stop bits and flow control mode
 * from the device, corrects any unsupported values, and configures the
 * termios structure to reflect the state of the device
 */
static void cp210x_get_termios(struct tty_struct *tty,
        struct usb_serial_port *port)
{
        unsigned int baud;

        if (tty) {
                cp210x_get_termios_port(tty->driver_data,
                        &tty->termios.c_cflag, &baud);
                tty_encode_baud_rate(tty, baud, baud);
        } else {
                unsigned int cflag;
                cflag = 0;
                cp210x_get_termios_port(port, &cflag, &baud);
        }
}

/*
 * cp210x_get_termios_port
 * This is the heart of cp210x_get_termios which always uses a &usb_serial_port.
 */
static void cp210x_get_termios_port(struct usb_serial_port *port,
        unsigned int *cflagp, unsigned int *baudp)
{
        struct device *dev = &port->dev;
        unsigned int cflag;
        u8 modem_ctl[16];
        u32 baud;
        u16 bits;

        cp210x_read_u32_reg(port, CP210X_GET_BAUDRATE, &baud);

        dev_dbg(dev, "%s - baud rate = %d\n", __func__, baud);
        *baudp = baud;

        cflag = *cflagp;

        cp210x_get_line_ctl(port, &bits);
        cflag &= ~CSIZE;
        switch (bits & BITS_DATA_MASK) {
        case BITS_DATA_5:
                dev_dbg(dev, "%s - data bits = 5\n", __func__);
                cflag |= CS5;
                break;
        case BITS_DATA_6:
                dev_dbg(dev, "%s - data bits = 6\n", __func__);
                cflag |= CS6;
                break;
        case BITS_DATA_7:
                dev_dbg(dev, "%s - data bits = 7\n", __func__);
                cflag |= CS7;
                break;
        case BITS_DATA_8:
                dev_dbg(dev, "%s - data bits = 8\n", __func__);
                cflag |= CS8;
                break;
        case BITS_DATA_9:
                dev_dbg(dev, "%s - data bits = 9 (not supported, using 8 data bits)\n", __func__);
                cflag |= CS8;
                bits &= ~BITS_DATA_MASK;
                bits |= BITS_DATA_8;
                cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
                break;
        default:
                dev_dbg(dev, "%s - Unknown number of data bits, using 8\n", __func__);
                cflag |= CS8;
                bits &= ~BITS_DATA_MASK;
                bits |= BITS_DATA_8;
                cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
                break;
        }

        switch (bits & BITS_PARITY_MASK) {
        case BITS_PARITY_NONE:
                dev_dbg(dev, "%s - parity = NONE\n", __func__);
                cflag &= ~PARENB;
                break;
        case BITS_PARITY_ODD:
                dev_dbg(dev, "%s - parity = ODD\n", __func__);
                cflag |= (PARENB|PARODD);
                break;
        case BITS_PARITY_EVEN:
                dev_dbg(dev, "%s - parity = EVEN\n", __func__);
                cflag &= ~PARODD;
                cflag |= PARENB;
                break;
        case BITS_PARITY_MARK:
                dev_dbg(dev, "%s - parity = MARK\n", __func__);
                cflag |= (PARENB|PARODD|CMSPAR);
                break;
        case BITS_PARITY_SPACE:
                dev_dbg(dev, "%s - parity = SPACE\n", __func__);
                cflag &= ~PARODD;
                cflag |= (PARENB|CMSPAR);
                break;
        default:
                dev_dbg(dev, "%s - Unknown parity mode, disabling parity\n", __func__);
                cflag &= ~PARENB;
                bits &= ~BITS_PARITY_MASK;
                cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
                break;
        }

        cflag &= ~CSTOPB;
        switch (bits & BITS_STOP_MASK) {
        case BITS_STOP_1:
                dev_dbg(dev, "%s - stop bits = 1\n", __func__);
                break;
        case BITS_STOP_1_5:
                dev_dbg(dev, "%s - stop bits = 1.5 (not supported, using 1 stop bit)\n", __func__);
                bits &= ~BITS_STOP_MASK;
                cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
                break;
        case BITS_STOP_2:
                dev_dbg(dev, "%s - stop bits = 2\n", __func__);
                cflag |= CSTOPB;
                break;
        default:
                dev_dbg(dev, "%s - Unknown number of stop bits, using 1 stop bit\n", __func__);
                bits &= ~BITS_STOP_MASK;
                cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
                break;
        }

        cp210x_read_reg_block(port, CP210X_GET_FLOW, modem_ctl,
                        sizeof(modem_ctl));
        if (modem_ctl[0] & 0x08) {
                dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);
                cflag |= CRTSCTS;
        } else {
                dev_dbg(dev, "%s - flow control = NONE\n", __func__);
                cflag &= ~CRTSCTS;
        }

        *cflagp = cflag;
}

/*
 * CP2101 supports the following baud rates:
 *
 *      300, 600, 1200, 1800, 2400, 4800, 7200, 9600, 14400, 19200, 28800,
 *      38400, 56000, 57600, 115200, 128000, 230400, 460800, 921600
 *
 * CP2102 and CP2103 support the following additional rates:
 *
 *      4000, 16000, 51200, 64000, 76800, 153600, 250000, 256000, 500000,
 *      576000
 *
 * The device will map a requested rate to a supported one, but the result
 * of requests for rates greater than 1053257 is undefined (see AN205).
 *
 * CP2104, CP2105 and CP2110 support most rates up to 2M, 921k and 1M baud,
 * respectively, with an error less than 1%. The actual rates are determined
 * by
 *
 *      div = round(freq / (2 x prescale x request))
 *      actual = freq / (2 x prescale x div)
 *
 * For CP2104 and CP2105 freq is 48Mhz and prescale is 4 for request <= 365bps
 * or 1 otherwise.
 * For CP2110 freq is 24Mhz and prescale is 4 for request <= 300bps or 1
 * otherwise.
 */
static void cp210x_change_speed(struct tty_struct *tty,
                struct usb_serial_port *port, struct ktermios *old_termios)
{
        u32 baud;

        baud = tty->termios.c_ospeed;

        /* This maps the requested rate to a rate valid on cp2102 or cp2103,
         * or to an arbitrary rate in [1M,2M].
         *
         * NOTE: B0 is not implemented.
         */
        baud = cp210x_quantise_baudrate(baud);

        dev_dbg(&port->dev, "%s - setting baud rate to %u\n", __func__, baud);
        if (cp210x_write_u32_reg(port, CP210X_SET_BAUDRATE, baud)) {
                dev_warn(&port->dev, "failed to set baud rate to %u\n", baud);
                if (old_termios)
                        baud = old_termios->c_ospeed;
                else
                        baud = 9600;
        }

        tty_encode_baud_rate(tty, baud, baud);
}

static void cp210x_set_termios(struct tty_struct *tty,
                struct usb_serial_port *port, struct ktermios *old_termios)
{
        struct device *dev = &port->dev;
        unsigned int cflag, old_cflag;
        u16 bits;
        u8 modem_ctl[16];

        cflag = tty->termios.c_cflag;
        old_cflag = old_termios->c_cflag;

        if (tty->termios.c_ospeed != old_termios->c_ospeed)
                cp210x_change_speed(tty, port, old_termios);

        /* If the number of data bits is to be updated */
        if ((cflag & CSIZE) != (old_cflag & CSIZE)) {
                cp210x_get_line_ctl(port, &bits);
                bits &= ~BITS_DATA_MASK;
                switch (cflag & CSIZE) {
                case CS5:
                        bits |= BITS_DATA_5;
                        dev_dbg(dev, "%s - data bits = 5\n", __func__);
                        break;
                case CS6:
                        bits |= BITS_DATA_6;
                        dev_dbg(dev, "%s - data bits = 6\n", __func__);
                        break;
                case CS7:
                        bits |= BITS_DATA_7;
                        dev_dbg(dev, "%s - data bits = 7\n", __func__);
                        break;
                case CS8:
                        bits |= BITS_DATA_8;
                        dev_dbg(dev, "%s - data bits = 8\n", __func__);
                        break;
                /*case CS9:
                        bits |= BITS_DATA_9;
                        dev_dbg(dev, "%s - data bits = 9\n", __func__);
                        break;*/
                default:
                        dev_dbg(dev, "cp210x driver does not support the number of bits requested, using 8 bit mode\n");
                        bits |= BITS_DATA_8;
                        break;
                }
                if (cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits))
                        dev_dbg(dev, "Number of data bits requested not supported by device\n");
        }

        if ((cflag     & (PARENB|PARODD|CMSPAR)) !=
            (old_cflag & (PARENB|PARODD|CMSPAR))) {
                cp210x_get_line_ctl(port, &bits);
                bits &= ~BITS_PARITY_MASK;
                if (cflag & PARENB) {
                        if (cflag & CMSPAR) {
                                if (cflag & PARODD) {
                                        bits |= BITS_PARITY_MARK;
                                        dev_dbg(dev, "%s - parity = MARK\n", __func__);
                                } else {
                                        bits |= BITS_PARITY_SPACE;
                                        dev_dbg(dev, "%s - parity = SPACE\n", __func__);
                                }
                        } else {
                                if (cflag & PARODD) {
                                        bits |= BITS_PARITY_ODD;
                                        dev_dbg(dev, "%s - parity = ODD\n", __func__);
                                } else {
                                        bits |= BITS_PARITY_EVEN;
                                        dev_dbg(dev, "%s - parity = EVEN\n", __func__);
                                }
                        }
                }
                if (cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits))
                        dev_dbg(dev, "Parity mode not supported by device\n");
        }

        if ((cflag & CSTOPB) != (old_cflag & CSTOPB)) {
                cp210x_get_line_ctl(port, &bits);
                bits &= ~BITS_STOP_MASK;
                if (cflag & CSTOPB) {
                        bits |= BITS_STOP_2;
                        dev_dbg(dev, "%s - stop bits = 2\n", __func__);
                } else {
                        bits |= BITS_STOP_1;
                        dev_dbg(dev, "%s - stop bits = 1\n", __func__);
                }
                if (cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits))
                        dev_dbg(dev, "Number of stop bits requested not supported by device\n");
        }

        if ((cflag & CRTSCTS) != (old_cflag & CRTSCTS)) {

                /* Only bytes 0, 4 and 7 out of first 8 have functional bits */

                cp210x_read_reg_block(port, CP210X_GET_FLOW, modem_ctl,
                                sizeof(modem_ctl));
                dev_dbg(dev, "%s - read modem controls = %02x .. .. .. %02x .. .. %02x\n",
                        __func__, modem_ctl[0], modem_ctl[4], modem_ctl[7]);

                if (cflag & CRTSCTS) {
                        modem_ctl[0] &= ~0x7B;
                        modem_ctl[0] |= 0x09;
                        modem_ctl[4] = 0x80;
                        /* FIXME - why clear reserved bits just read? */
                        modem_ctl[5] = 0;
                        modem_ctl[6] = 0;
                        modem_ctl[7] = 0;
                        dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);
                } else {
                        modem_ctl[0] &= ~0x7B;
                        modem_ctl[0] |= 0x01;
                        /* FIXME - OR here instead of assignment looks wrong */
                        modem_ctl[4] |= 0x40;
                        dev_dbg(dev, "%s - flow control = NONE\n", __func__);
                }

                dev_dbg(dev, "%s - write modem controls = %02x .. .. .. %02x .. .. %02x\n",
                        __func__, modem_ctl[0], modem_ctl[4], modem_ctl[7]);
                cp210x_write_reg_block(port, CP210X_SET_FLOW, modem_ctl,
                                sizeof(modem_ctl));
        }

}

static int cp210x_tiocmset(struct tty_struct *tty,
                unsigned int set, unsigned int clear)
{
        struct usb_serial_port *port = tty->driver_data;
        return cp210x_tiocmset_port(port, set, clear);
}

static int cp210x_tiocmset_port(struct usb_serial_port *port,
                unsigned int set, unsigned int clear)
{
        u16 control = 0;

        if (set & TIOCM_RTS) {
                control |= CONTROL_RTS;

                control |= CONTROL_WRITE_RTS;
        }
        if (set & TIOCM_DTR) {
                control |= CONTROL_DTR;
                control |= CONTROL_WRITE_DTR;
        }
        if (clear & TIOCM_RTS) {
                control &= ~CONTROL_RTS;
                control |= CONTROL_WRITE_RTS;
        }
        if (clear & TIOCM_DTR) {
                control &= ~CONTROL_DTR;
                control |= CONTROL_WRITE_DTR;
        }

        dev_dbg(&port->dev, "%s - control = 0x%.4x\n", __func__, control);

        return cp210x_write_u16_reg(port, CP210X_SET_MHS, control);
}

static void cp210x_dtr_rts(struct usb_serial_port *p, int on)
{
        if (on)
                cp210x_tiocmset_port(p, TIOCM_DTR|TIOCM_RTS, 0);
        else
                cp210x_tiocmset_port(p, 0, TIOCM_DTR|TIOCM_RTS);
}

static int cp210x_tiocmget(struct tty_struct *tty)
{
        struct usb_serial_port *port = tty->driver_data;
        u8 control;
        int result;

        cp210x_read_u8_reg(port, CP210X_GET_MDMSTS, &control);

        result = ((control & CONTROL_DTR) ? TIOCM_DTR : 0)
                |((control & CONTROL_RTS) ? TIOCM_RTS : 0)
                |((control & CONTROL_CTS) ? TIOCM_CTS : 0)
                |((control & CONTROL_DSR) ? TIOCM_DSR : 0)
                |((control & CONTROL_RING)? TIOCM_RI  : 0)
                |((control & CONTROL_DCD) ? TIOCM_CD  : 0);

        dev_dbg(&port->dev, "%s - control = 0x%.2x\n", __func__, control);

        return result;
}

static void cp210x_break_ctl(struct tty_struct *tty, int break_state)
{
        struct usb_serial_port *port = tty->driver_data;
        u16 state;

        if (break_state == 0)
                state = BREAK_OFF;
        else
                state = BREAK_ON;
        dev_dbg(&port->dev, "%s - turning break %s\n", __func__,
                state == BREAK_OFF ? "off" : "on");
        cp210x_write_u16_reg(port, CP210X_SET_BREAK, state);
}

static int cp210x_port_probe(struct usb_serial_port *port)
{
        struct usb_serial *serial = port->serial;
        struct usb_host_interface *cur_altsetting;
        struct cp210x_port_private *port_priv;
        int ret;

        port_priv = kzalloc(sizeof(*port_priv), GFP_KERNEL);
        if (!port_priv)
                return -ENOMEM;

        cur_altsetting = serial->interface->cur_altsetting;
        port_priv->bInterfaceNumber = cur_altsetting->desc.bInterfaceNumber;

        usb_set_serial_port_data(port, port_priv);

        ret = cp210x_detect_swapped_line_ctl(port);
        if (ret) {
                kfree(port_priv);
                return ret;
        }

        return 0;
}

static int cp210x_port_remove(struct usb_serial_port *port)
{
        struct cp210x_port_private *port_priv;

        port_priv = usb_get_serial_port_data(port);
        kfree(port_priv);

        return 0;
}

module_usb_serial_driver(serial_drivers, id_table);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");