--- a
+++ b/cp210x.c
@@ -0,0 +1,932 @@
+/*
+ * 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 int cp210x_ioctl(struct tty_struct *tty,
+	unsigned int cmd, unsigned long arg);
+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 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_startup(struct usb_serial *);
+static void cp210x_release(struct usb_serial *);
+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(0x08e6, 0x5501) }, /* Gemalto Prox-PU/CU contactless smartcard reader */
+	{ USB_DEVICE(0x08FD, 0x000A) }, /* Digianswer A/S , ZigBee/802.15.4 MAC Device */
+	{ 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(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, 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, 0x8293) }, /* Telegesis ETRX2USB */
+	{ 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, 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, 0xEA60) }, /* Silicon Labs factory default */
+	{ USB_DEVICE(0x10C4, 0xEA61) }, /* Silicon Labs factory default */
+	{ USB_DEVICE(0x10C4, 0xEA70) }, /* Silicon Labs factory default */
+	{ USB_DEVICE(0x10C4, 0xEA80) }, /* 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(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(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(0x1BE3, 0x07A6) }, /* WAGO 750-923 USB Service Cable */
+	{ USB_DEVICE(0x1E29, 0x0102) }, /* Festo CPX-USB */
+	{ USB_DEVICE(0x1E29, 0x0501) }, /* Festo CMSP */
+	{ 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_serial_private {
+	__u8			bInterfaceNumber;
+};
+
+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,
+	.ioctl			= cp210x_ioctl,
+	.break_ctl		= cp210x_break_ctl,
+	.set_termios		= cp210x_set_termios,
+	.tiocmget		= cp210x_tiocmget,
+	.tiocmset		= cp210x_tiocmset,
+	.attach			= cp210x_startup,
+	.release		= cp210x_release,
+	.dtr_rts		= cp210x_dtr_rts
+};
+
+static struct usb_serial_driver * const serial_drivers[] = {
+	&cp210x_device, NULL
+};
+
+/* IOCTLs */
+#define IOCTL_GPIOGET	 0x8000
+#define IOCTL_GPIOSET	 0x8001
+
+/* 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
+#define CP210X_VENDOR_SPECIFIC	0xFF
+
+/* CP210X_IFC_ENABLE */
+#define UART_ENABLE		0x0001
+#define UART_DISABLE		0x0000
+
+/* CP210X_VENDOR_SPECIFIC */
+#define CP210X_WRITE_LATCH	0x37E1
+#define CP210X_READ_LATCH	0x00C2
+
+/* 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_config
+ * Reads from the CP210x configuration registers
+ * 'size' is specified in bytes.
+ * 'data' is a pointer to a pre-allocated array of integers large
+ * enough to hold 'size' bytes (with 4 bytes to each integer)
+ */
+static int cp210x_get_config(struct usb_serial_port *port, u8 request,
+		unsigned int *data, int size)
+{
+	struct usb_serial *serial = port->serial;
+	struct cp210x_serial_private *spriv = usb_get_serial_data(serial);
+	__le32 *buf;
+	int result, i, length;
+
+	/* Number of integers required to contain the array */
+	length = (((size - 1) | 3) + 1) / 4;
+
+	buf = kcalloc(length, sizeof(__le32), GFP_KERNEL);
+	if (!buf) {
+		dev_err(&port->dev, "%s - out of memory.\n", __func__);
+		return -ENOMEM;
+	}
+
+	/* Issue the request, attempting to read 'size' bytes */
+	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
+				request, REQTYPE_INTERFACE_TO_HOST, 0x0000,
+				spriv->bInterfaceNumber, buf, size,
+				USB_CTRL_GET_TIMEOUT);
+
+	/* Convert data into an array of integers */
+	for (i = 0; i < length; i++)
+		data[i] = le32_to_cpu(buf[i]);
+
+	kfree(buf);
+
+	if (result != size) {
+		dev_dbg(&port->dev, "%s - Unable to send config request, request=0x%x size=%d result=%d\n",
+			__func__, request, size, result);
+		if (result > 0)
+			result = -EPROTO;
+
+		return result;
+	}
+
+	return 0;
+}
+
+/*
+ * cp210x_set_config
+ * Writes to the CP210x configuration registers
+ * Values less than 16 bits wide are sent directly
+ * 'size' is specified in bytes.
+ */
+static int cp210x_set_config(struct usb_serial_port *port, u8 request,
+		unsigned int *data, int size)
+{
+	struct usb_serial *serial = port->serial;
+	struct cp210x_serial_private *spriv = usb_get_serial_data(serial);
+	__le32 *buf;
+	int result, i, length;
+
+	/* Number of integers required to contain the array */
+	length = (((size - 1) | 3) + 1) / 4;
+
+	buf = kmalloc(length * sizeof(__le32), GFP_KERNEL);
+	if (!buf) {
+		dev_err(&port->dev, "%s - out of memory.\n", __func__);
+		return -ENOMEM;
+	}
+
+	/* Array of integers into bytes */
+	for (i = 0; i < length; i++)
+		buf[i] = cpu_to_le32(data[i]);
+
+	if (size > 2) {
+		result = usb_control_msg(serial->dev,
+				usb_sndctrlpipe(serial->dev, 0),
+				request, REQTYPE_HOST_TO_INTERFACE, 0x0000,
+				spriv->bInterfaceNumber, buf, size,
+				USB_CTRL_SET_TIMEOUT);
+	} else {
+		result = usb_control_msg(serial->dev,
+				usb_sndctrlpipe(serial->dev, 0),
+				request, REQTYPE_HOST_TO_INTERFACE, data[0],
+				spriv->bInterfaceNumber, NULL, 0,
+				USB_CTRL_SET_TIMEOUT);
+	}
+
+	kfree(buf);
+
+	if ((size > 2 && result != size) || result < 0) {
+		dev_dbg(&port->dev, "%s - Unable to send request, request=0x%x size=%d result=%d\n",
+			__func__, request, size, result);
+		if (result > 0)
+			result = -EPROTO;
+
+		return result;
+	}
+
+	return 0;
+}
+
+/*
+ * cp210x_set_config_single
+ * Convenience function for calling cp210x_set_config on single data values
+ * without requiring an integer pointer
+ */
+static inline int cp210x_set_config_single(struct usb_serial_port *port,
+		u8 request, unsigned int data)
+{
+	return cp210x_set_config(port, request, &data, 2);
+}
+
+/*
+ * 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_set_config_single(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);
+
+	mutex_lock(&port->serial->disc_mutex);
+	if (!port->serial->disconnected)
+		cp210x_set_config_single(port, CP210X_IFC_ENABLE, UART_DISABLE);
+	mutex_unlock(&port->serial->disc_mutex);
+}
+
+static int cp210x_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct usb_serial *serial = port->serial;
+	int result = 0;
+	struct cp210x_serial_private *spriv = usb_get_serial_data(serial);
+	unsigned int latch_setting = 0;
+
+	switch (cmd) {
+	    case IOCTL_GPIOGET:
+		result = usb_control_msg(
+			      serial->dev,
+			      usb_rcvctrlpipe(serial->dev, 0),
+			      CP210X_VENDOR_SPECIFIC,
+			      REQTYPE_DEVICE_TO_HOST,
+			      CP210X_READ_LATCH,
+			      spriv->bInterfaceNumber,
+			      &latch_setting, 1,
+			      USB_CTRL_GET_TIMEOUT);
+		if (result != 1)
+		    return -EPROTO;
+		*(unsigned long *)arg = (unsigned long)latch_setting;
+		return 0;
+	    break;
+	    case IOCTL_GPIOSET:
+		latch_setting = *(unsigned int *)arg & 0x000000FF;
+		//why [23:16] bits are taken for value is unknown
+		latch_setting |= (*(unsigned int *)arg & 0x00FF0000) >> 8;
+		
+		result = usb_control_msg(
+			      serial->dev,
+			      usb_sndctrlpipe(serial->dev, 0),
+			      CP210X_VENDOR_SPECIFIC,
+			      REQTYPE_HOST_TO_DEVICE,
+			      CP210X_WRITE_LATCH,
+			      latch_setting,
+			      NULL, 0,
+			      USB_CTRL_SET_TIMEOUT);
+		if (result != 0)
+		    return -EPROTO;
+		return 0;
+	    break;
+	    default:
+	    break;
+	}
+	return -ENOIOCTLCMD;
+}
+
+/*
+ * 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, modem_ctl[4];
+	unsigned int baud;
+	unsigned int bits;
+
+	cp210x_get_config(port, CP210X_GET_BAUDRATE, &baud, 4);
+
+	dev_dbg(dev, "%s - baud rate = %d\n", __func__, baud);
+	*baudp = baud;
+
+	cflag = *cflagp;
+
+	cp210x_get_config(port, CP210X_GET_LINE_CTL, &bits, 2);
+	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_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
+		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_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
+		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_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
+		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_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
+		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_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
+		break;
+	}
+
+	cp210x_get_config(port, CP210X_GET_FLOW, modem_ctl, 16);
+	if (modem_ctl[0] & 0x0008) {
+		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_set_config(port, CP210X_SET_BAUDRATE, &baud,
+							sizeof(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;
+	unsigned int bits;
+	unsigned int modem_ctl[4];
+
+	dev_dbg(dev, "%s - port %d\n", __func__, port->number);
+
+	if (!tty)
+		return;
+
+	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_config(port, CP210X_GET_LINE_CTL, &bits, 2);
+		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_set_config(port, CP210X_SET_LINE_CTL, &bits, 2))
+			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_config(port, CP210X_GET_LINE_CTL, &bits, 2);
+		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_set_config(port, CP210X_SET_LINE_CTL, &bits, 2))
+			dev_dbg(dev, "Parity mode not supported by device\n");
+	}
+
+	if ((cflag & CSTOPB) != (old_cflag & CSTOPB)) {
+		cp210x_get_config(port, CP210X_GET_LINE_CTL, &bits, 2);
+		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_set_config(port, CP210X_SET_LINE_CTL, &bits, 2))
+			dev_dbg(dev, "Number of stop bits requested not supported by device\n");
+	}
+
+	if ((cflag & CRTSCTS) != (old_cflag & CRTSCTS)) {
+		cp210x_get_config(port, CP210X_GET_FLOW, modem_ctl, 16);
+		dev_dbg(dev, "%s - read modem controls = 0x%.4x 0x%.4x 0x%.4x 0x%.4x\n",
+			__func__, modem_ctl[0], modem_ctl[1],
+			modem_ctl[2], modem_ctl[3]);
+
+		if (cflag & CRTSCTS) {
+			modem_ctl[0] &= ~0x7B;
+			modem_ctl[0] |= 0x09;
+			modem_ctl[1] = 0x80;
+			dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);
+		} else {
+			modem_ctl[0] &= ~0x7B;
+			modem_ctl[0] |= 0x01;
+			modem_ctl[1] |= 0x40;
+			dev_dbg(dev, "%s - flow control = NONE\n", __func__);
+		}
+
+		dev_dbg(dev, "%s - write modem controls = 0x%.4x 0x%.4x 0x%.4x 0x%.4x\n",
+			__func__, modem_ctl[0], modem_ctl[1],
+			modem_ctl[2], modem_ctl[3]);
+		cp210x_set_config(port, CP210X_SET_FLOW, modem_ctl, 16);
+	}
+
+}
+
+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)
+{
+	unsigned int 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_set_config(port, CP210X_SET_MHS, &control, 2);
+}
+
+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;
+	unsigned int control;
+	int result;
+
+	cp210x_get_config(port, CP210X_GET_MDMSTS, &control, 1);
+
+	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;
+	unsigned int 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_set_config(port, CP210X_SET_BREAK, &state, 2);
+}
+
+static int cp210x_startup(struct usb_serial *serial)
+{
+	struct usb_host_interface *cur_altsetting;
+	struct cp210x_serial_private *spriv;
+
+	/* cp210x buffers behave strangely unless device is reset */
+	usb_reset_device(serial->dev);
+
+	spriv = kzalloc(sizeof(*spriv), GFP_KERNEL);
+	if (!spriv)
+		return -ENOMEM;
+
+	cur_altsetting = serial->interface->cur_altsetting;
+	spriv->bInterfaceNumber = cur_altsetting->desc.bInterfaceNumber;
+
+	usb_set_serial_data(serial, spriv);
+
+	return 0;
+}
+
+static void cp210x_release(struct usb_serial *serial)
+{
+	struct cp210x_serial_private *spriv;
+
+	spriv = usb_get_serial_data(serial);
+	kfree(spriv);
+}
+
+module_usb_serial_driver(serial_drivers, id_table);
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");