[mirror_ubuntu-bionic-kernel.git] / drivers / usb / serial / ch341.c

/*
 * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
 * Copyright 2007, Werner Cornelius <werner@cornelius-consult.de>
 * Copyright 2009, Boris Hajduk <boris@hajduk.org>
 *
 * ch341.c implements a serial port driver for the Winchiphead CH341.
 *
 * The CH341 device can be used to implement an RS232 asynchronous
 * serial port, an IEEE-1284 parallel printer port or a memory-like
 * interface. In all cases the CH341 supports an I2C interface as well.
 * This driver only supports the asynchronous serial interface.
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/tty.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/serial.h>
#include <asm/unaligned.h>

#define DEFAULT_BAUD_RATE 9600
#define DEFAULT_TIMEOUT   1000

/* flags for IO-Bits */
#define CH341_BIT_RTS (1 << 6)
#define CH341_BIT_DTR (1 << 5)

/******************************/
/* interrupt pipe definitions */
/******************************/
/* always 4 interrupt bytes */
/* first irq byte normally 0x08 */
/* second irq byte base 0x7d + below */
/* third irq byte base 0x94 + below */
/* fourth irq byte normally 0xee */

/* second interrupt byte */
#define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */

/* status returned in third interrupt answer byte, inverted in data
   from irq */
#define CH341_BIT_CTS 0x01
#define CH341_BIT_DSR 0x02
#define CH341_BIT_RI  0x04
#define CH341_BIT_DCD 0x08
#define CH341_BITS_MODEM_STAT 0x0f /* all bits */

/*******************************/
/* baudrate calculation factor */
/*******************************/
#define CH341_BAUDBASE_FACTOR 1532620800
#define CH341_BAUDBASE_DIVMAX 3

/* Break support - the information used to implement this was gleaned from
 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe.  Domo arigato.
 */

#define CH341_REQ_WRITE_REG    0x9A
#define CH341_REQ_READ_REG     0x95
#define CH341_REG_BREAK1       0x05
#define CH341_REG_BREAK2       0x18
#define CH341_NBREAK_BITS_REG1 0x01
#define CH341_NBREAK_BITS_REG2 0x40


static int debug;

static const struct usb_device_id id_table[] = {
	{ USB_DEVICE(0x4348, 0x5523) },
	{ USB_DEVICE(0x1a86, 0x7523) },
	{ USB_DEVICE(0x1a86, 0x5523) },
	{ },
};
MODULE_DEVICE_TABLE(usb, id_table);

struct ch341_private {
	spinlock_t lock; /* access lock */
	wait_queue_head_t delta_msr_wait; /* wait queue for modem status */
	unsigned baud_rate; /* set baud rate */
	u8 line_control; /* set line control value RTS/DTR */
	u8 line_status; /* active status of modem control inputs */
	u8 multi_status_change; /* status changed multiple since last call */
};

static int ch341_control_out(struct usb_device *dev, u8 request,
			     u16 value, u16 index)
{
	int r;
	dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40,
		(int)request, (int)value, (int)index);

	r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
			    USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
			    value, index, NULL, 0, DEFAULT_TIMEOUT);

	return r;
}

static int ch341_control_in(struct usb_device *dev,
			    u8 request, u16 value, u16 index,
			    char *buf, unsigned bufsize)
{
	int r;
	dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40,
		(int)request, (int)value, (int)index, buf, (int)bufsize);

	r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
			    USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
			    value, index, buf, bufsize, DEFAULT_TIMEOUT);
	return r;
}

static int ch341_set_baudrate(struct usb_device *dev,
			      struct ch341_private *priv)
{
	short a, b;
	int r;
	unsigned long factor;
	short divisor;

	dbg("ch341_set_baudrate(%d)", priv->baud_rate);

	if (!priv->baud_rate)
		return -EINVAL;
	factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
	divisor = CH341_BAUDBASE_DIVMAX;

	while ((factor > 0xfff0) && divisor) {
		factor >>= 3;
		divisor--;
	}

	if (factor > 0xfff0)
		return -EINVAL;

	factor = 0x10000 - factor;
	a = (factor & 0xff00) | divisor;
	b = factor & 0xff;

	r = ch341_control_out(dev, 0x9a, 0x1312, a);
	if (!r)
		r = ch341_control_out(dev, 0x9a, 0x0f2c, b);

	return r;
}

static int ch341_set_handshake(struct usb_device *dev, u8 control)
{
	dbg("ch341_set_handshake(0x%02x)", control);
	return ch341_control_out(dev, 0xa4, ~control, 0);
}

static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
{
	char *buffer;
	int r;
	const unsigned size = 8;
	unsigned long flags;

	dbg("ch341_get_status()");

	buffer = kmalloc(size, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
	if (r < 0)
		goto out;

	/* setup the private status if available */
	if (r == 2) {
		r = 0;
		spin_lock_irqsave(&priv->lock, flags);
		priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
		priv->multi_status_change = 0;
		spin_unlock_irqrestore(&priv->lock, flags);
	} else
		r = -EPROTO;

out:	kfree(buffer);
	return r;
}

/* -------------------------------------------------------------------------- */

static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
{
	char *buffer;
	int r;
	const unsigned size = 8;

	dbg("ch341_configure()");

	buffer = kmalloc(size, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	/* expect two bytes 0x27 0x00 */
	r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
	if (r < 0)
		goto out;

	r = ch341_control_out(dev, 0xa1, 0, 0);
	if (r < 0)
		goto out;

	r = ch341_set_baudrate(dev, priv);
	if (r < 0)
		goto out;

	/* expect two bytes 0x56 0x00 */
	r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
	if (r < 0)
		goto out;

	r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
	if (r < 0)
		goto out;

	/* expect 0xff 0xee */
	r = ch341_get_status(dev, priv);
	if (r < 0)
		goto out;

	r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
	if (r < 0)
		goto out;

	r = ch341_set_baudrate(dev, priv);
	if (r < 0)
		goto out;

	r = ch341_set_handshake(dev, priv->line_control);
	if (r < 0)
		goto out;

	/* expect 0x9f 0xee */
	r = ch341_get_status(dev, priv);

out:	kfree(buffer);
	return r;
}

/* allocate private data */
static int ch341_attach(struct usb_serial *serial)
{
	struct ch341_private *priv;
	int r;

	dbg("ch341_attach()");

	/* private data */
	priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	spin_lock_init(&priv->lock);
	init_waitqueue_head(&priv->delta_msr_wait);
	priv->baud_rate = DEFAULT_BAUD_RATE;
	priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;

	r = ch341_configure(serial->dev, priv);
	if (r < 0)
		goto error;

	usb_set_serial_port_data(serial->port[0], priv);
	return 0;

error:	kfree(priv);
	return r;
}

static int ch341_carrier_raised(struct usb_serial_port *port)
{
	struct ch341_private *priv = usb_get_serial_port_data(port);
	if (priv->line_status & CH341_BIT_DCD)
		return 1;
	return 0;
}

static void ch341_dtr_rts(struct usb_serial_port *port, int on)
{
	struct ch341_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;

	dbg("%s - port %d", __func__, port->number);
	/* drop DTR and RTS */
	spin_lock_irqsave(&priv->lock, flags);
	if (on)
		priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
	else
		priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
	spin_unlock_irqrestore(&priv->lock, flags);
	ch341_set_handshake(port->serial->dev, priv->line_control);
	wake_up_interruptible(&priv->delta_msr_wait);
}

static void ch341_close(struct usb_serial_port *port)
{
	dbg("%s - port %d", __func__, port->number);

	usb_serial_generic_close(port);
	usb_kill_urb(port->interrupt_in_urb);
}


/* open this device, set default parameters */
static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
{
	struct usb_serial *serial = port->serial;
	struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
	int r;

	dbg("ch341_open()");

	priv->baud_rate = DEFAULT_BAUD_RATE;

	r = ch341_configure(serial->dev, priv);
	if (r)
		goto out;

	r = ch341_set_handshake(serial->dev, priv->line_control);
	if (r)
		goto out;

	r = ch341_set_baudrate(serial->dev, priv);
	if (r)
		goto out;

	dbg("%s - submitting interrupt urb", __func__);
	port->interrupt_in_urb->dev = serial->dev;
	r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
	if (r) {
		dev_err(&port->dev, "%s - failed submitting interrupt urb,"
			" error %d\n", __func__, r);
		ch341_close(port);
		return -EPROTO;
	}

	r = usb_serial_generic_open(tty, port);

out:	return r;
}

/* Old_termios contains the original termios settings and
 * tty->termios contains the new setting to be used.
 */
static void ch341_set_termios(struct tty_struct *tty,
		struct usb_serial_port *port, struct ktermios *old_termios)
{
	struct ch341_private *priv = usb_get_serial_port_data(port);
	unsigned baud_rate;
	unsigned long flags;

	dbg("ch341_set_termios()");

	baud_rate = tty_get_baud_rate(tty);

	priv->baud_rate = baud_rate;

	if (baud_rate) {
		spin_lock_irqsave(&priv->lock, flags);
		priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
		spin_unlock_irqrestore(&priv->lock, flags);
		ch341_set_baudrate(port->serial->dev, priv);
	} else {
		spin_lock_irqsave(&priv->lock, flags);
		priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
		spin_unlock_irqrestore(&priv->lock, flags);
	}

	ch341_set_handshake(port->serial->dev, priv->line_control);

	/* Unimplemented:
	 * (cflag & CSIZE) : data bits [5, 8]
	 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
	 * (cflag & CSTOPB) : stop bits [1, 2]
	 */
}

static void ch341_break_ctl(struct tty_struct *tty, int break_state)
{
	const uint16_t ch341_break_reg =
		CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
	struct usb_serial_port *port = tty->driver_data;
	int r;
	uint16_t reg_contents;
	uint8_t *break_reg;

	dbg("%s()", __func__);

	break_reg = kmalloc(2, GFP_KERNEL);
	if (!break_reg) {
		dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
		return;
	}

	r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
			ch341_break_reg, 0, break_reg, 2);
	if (r < 0) {
		dev_err(&port->dev, "%s - USB control read error (%d)\n",
				__func__, r);
		goto out;
	}
	dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
			__func__, break_reg[0], break_reg[1]);
	if (break_state != 0) {
		dbg("%s - Enter break state requested", __func__);
		break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
		break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
	} else {
		dbg("%s - Leave break state requested", __func__);
		break_reg[0] |= CH341_NBREAK_BITS_REG1;
		break_reg[1] |= CH341_NBREAK_BITS_REG2;
	}
	dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
			__func__, break_reg[0], break_reg[1]);
	reg_contents = get_unaligned_le16(break_reg);
	r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
			ch341_break_reg, reg_contents);
	if (r < 0)
		dev_err(&port->dev, "%s - USB control write error (%d)\n",
				__func__, r);
out:
	kfree(break_reg);
}

static int ch341_tiocmset(struct tty_struct *tty,
			  unsigned int set, unsigned int clear)
{
	struct usb_serial_port *port = tty->driver_data;
	struct ch341_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;
	u8 control;

	spin_lock_irqsave(&priv->lock, flags);
	if (set & TIOCM_RTS)
		priv->line_control |= CH341_BIT_RTS;
	if (set & TIOCM_DTR)
		priv->line_control |= CH341_BIT_DTR;
	if (clear & TIOCM_RTS)
		priv->line_control &= ~CH341_BIT_RTS;
	if (clear & TIOCM_DTR)
		priv->line_control &= ~CH341_BIT_DTR;
	control = priv->line_control;
	spin_unlock_irqrestore(&priv->lock, flags);

	return ch341_set_handshake(port->serial->dev, control);
}

static void ch341_read_int_callback(struct urb *urb)
{
	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
	unsigned char *data = urb->transfer_buffer;
	unsigned int actual_length = urb->actual_length;
	int status;

	dbg("%s (%d)", __func__, port->number);

	switch (urb->status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* this urb is terminated, clean up */
		dbg("%s - urb shutting down with status: %d", __func__,
		    urb->status);
		return;
	default:
		dbg("%s - nonzero urb status received: %d", __func__,
		    urb->status);
		goto exit;
	}

	usb_serial_debug_data(debug, &port->dev, __func__,
			      urb->actual_length, urb->transfer_buffer);

	if (actual_length >= 4) {
		struct ch341_private *priv = usb_get_serial_port_data(port);
		unsigned long flags;
		u8 prev_line_status = priv->line_status;

		spin_lock_irqsave(&priv->lock, flags);
		priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
		if ((data[1] & CH341_MULT_STAT))
			priv->multi_status_change = 1;
		spin_unlock_irqrestore(&priv->lock, flags);

		if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
			struct tty_struct *tty = tty_port_tty_get(&port->port);
			if (tty)
				usb_serial_handle_dcd_change(port, tty,
					    priv->line_status & CH341_BIT_DCD);
			tty_kref_put(tty);
		}

		wake_up_interruptible(&priv->delta_msr_wait);
	}

exit:
	status = usb_submit_urb(urb, GFP_ATOMIC);
	if (status)
		dev_err(&urb->dev->dev,
			"%s - usb_submit_urb failed with result %d\n",
			__func__, status);
}

static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
{
	struct ch341_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;
	u8 prevstatus;
	u8 status;
	u8 changed;
	u8 multi_change = 0;

	spin_lock_irqsave(&priv->lock, flags);
	prevstatus = priv->line_status;
	priv->multi_status_change = 0;
	spin_unlock_irqrestore(&priv->lock, flags);

	while (!multi_change) {
		interruptible_sleep_on(&priv->delta_msr_wait);
		/* see if a signal did it */
		if (signal_pending(current))
			return -ERESTARTSYS;

		spin_lock_irqsave(&priv->lock, flags);
		status = priv->line_status;
		multi_change = priv->multi_status_change;
		spin_unlock_irqrestore(&priv->lock, flags);

		changed = prevstatus ^ status;

		if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
		    ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
		    ((arg & TIOCM_CD)  && (changed & CH341_BIT_DCD)) ||
		    ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
			return 0;
		}
		prevstatus = status;
	}

	return 0;
}

static int ch341_ioctl(struct tty_struct *tty,
			unsigned int cmd, unsigned long arg)
{
	struct usb_serial_port *port = tty->driver_data;
	dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);

	switch (cmd) {
	case TIOCMIWAIT:
		dbg("%s (%d) TIOCMIWAIT", __func__,  port->number);
		return wait_modem_info(port, arg);

	default:
		dbg("%s not supported = 0x%04x", __func__, cmd);
		break;
	}

	return -ENOIOCTLCMD;
}

static int ch341_tiocmget(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct ch341_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;
	u8 mcr;
	u8 status;
	unsigned int result;

	dbg("%s (%d)", __func__, port->number);

	spin_lock_irqsave(&priv->lock, flags);
	mcr = priv->line_control;
	status = priv->line_status;
	spin_unlock_irqrestore(&priv->lock, flags);

	result = ((mcr & CH341_BIT_DTR)		? TIOCM_DTR : 0)
		  | ((mcr & CH341_BIT_RTS)	? TIOCM_RTS : 0)
		  | ((status & CH341_BIT_CTS)	? TIOCM_CTS : 0)
		  | ((status & CH341_BIT_DSR)	? TIOCM_DSR : 0)
		  | ((status & CH341_BIT_RI)	? TIOCM_RI  : 0)
		  | ((status & CH341_BIT_DCD)	? TIOCM_CD  : 0);

	dbg("%s - result = %x", __func__, result);

	return result;
}


static int ch341_reset_resume(struct usb_interface *intf)
{
	struct usb_device *dev = interface_to_usbdev(intf);
	struct usb_serial *serial = NULL;
	struct ch341_private *priv;

	serial = usb_get_intfdata(intf);
	priv = usb_get_serial_port_data(serial->port[0]);

	/*reconfigure ch341 serial port after bus-reset*/
	ch341_configure(dev, priv);

	usb_serial_resume(intf);

	return 0;
}

static struct usb_driver ch341_driver = {
	.name		= "ch341",
	.probe		= usb_serial_probe,
	.disconnect	= usb_serial_disconnect,
	.suspend	= usb_serial_suspend,
	.resume		= usb_serial_resume,
	.reset_resume	= ch341_reset_resume,
	.id_table	= id_table,
	.no_dynamic_id	= 1,
	.supports_autosuspend =	1,
};

static struct usb_serial_driver ch341_device = {
	.driver = {
		.owner	= THIS_MODULE,
		.name	= "ch341-uart",
	},
	.id_table          = id_table,
	.usb_driver        = &ch341_driver,
	.num_ports         = 1,
	.open              = ch341_open,
	.dtr_rts	   = ch341_dtr_rts,
	.carrier_raised	   = ch341_carrier_raised,
	.close             = ch341_close,
	.ioctl             = ch341_ioctl,
	.set_termios       = ch341_set_termios,
	.break_ctl         = ch341_break_ctl,
	.tiocmget          = ch341_tiocmget,
	.tiocmset          = ch341_tiocmset,
	.read_int_callback = ch341_read_int_callback,
	.attach            = ch341_attach,
};

static int __init ch341_init(void)
{
	int retval;

	retval = usb_serial_register(&ch341_device);
	if (retval)
		return retval;
	retval = usb_register(&ch341_driver);
	if (retval)
		usb_serial_deregister(&ch341_device);
	return retval;
}

static void __exit ch341_exit(void)
{
	usb_deregister(&ch341_driver);
	usb_serial_deregister(&ch341_device);
}

module_init(ch341_init);
module_exit(ch341_exit);
MODULE_LICENSE("GPL");

module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");

/* EOF ch341.c */
Commit	Line	Data
6ce76104 FK	1	/*
6ce76104 FK	2	* Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
664d5df9 WC	3	* Copyright 2007, Werner Cornelius <werner@cornelius-consult.de>
664d5df9 WC	4	* Copyright 2009, Boris Hajduk <boris@hajduk.org>
6ce76104 FK	5	*
	6	* ch341.c implements a serial port driver for the Winchiphead CH341.
	7	*
	8	* The CH341 device can be used to implement an RS232 asynchronous
	9	* serial port, an IEEE-1284 parallel printer port or a memory-like
	10	* interface. In all cases the CH341 supports an I2C interface as well.
	11	* This driver only supports the asynchronous serial interface.
	12	*
	13	* This program is free software; you can redistribute it and/or
	14	* modify it under the terms of the GNU General Public License version
	15	* 2 as published by the Free Software Foundation.
	16	*/
	17
	18	#include <linux/kernel.h>
	19	#include <linux/init.h>
	20	#include <linux/tty.h>
	21	#include <linux/module.h>
5a0e3ad6	22	#include <linux/slab.h>
6ce76104 FK	23	#include <linux/usb.h>
	24	#include <linux/usb/serial.h>
	25	#include <linux/serial.h>
5be796f0	26	#include <asm/unaligned.h>
6ce76104	27
664d5df9	28	#define DEFAULT_BAUD_RATE 9600
6ce76104 FK	29	#define DEFAULT_TIMEOUT 1000
6ce76104 FK	30
664d5df9 WC	31	/* flags for IO-Bits */
	32	#define CH341_BIT_RTS (1 << 6)
	33	#define CH341_BIT_DTR (1 << 5)
	34
	35	/******************************/
	36	/* interrupt pipe definitions */
	37	/******************************/
	38	/* always 4 interrupt bytes */
	39	/* first irq byte normally 0x08 */
	40	/* second irq byte base 0x7d + below */
	41	/* third irq byte base 0x94 + below */
	42	/* fourth irq byte normally 0xee */
	43
	44	/* second interrupt byte */
	45	#define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
	46
	47	/* status returned in third interrupt answer byte, inverted in data
	48	from irq */
	49	#define CH341_BIT_CTS 0x01
	50	#define CH341_BIT_DSR 0x02
	51	#define CH341_BIT_RI 0x04
	52	#define CH341_BIT_DCD 0x08
	53	#define CH341_BITS_MODEM_STAT 0x0f /* all bits */
	54
	55	/*******************************/
	56	/* baudrate calculation factor */
	57	/*******************************/
	58	#define CH341_BAUDBASE_FACTOR 1532620800
	59	#define CH341_BAUDBASE_DIVMAX 3
	60
492896f0 TS	61	/* Break support - the information used to implement this was gleaned from
	62	* the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
	63	*/
	64
	65	#define CH341_REQ_WRITE_REG 0x9A
	66	#define CH341_REQ_READ_REG 0x95
	67	#define CH341_REG_BREAK1 0x05
	68	#define CH341_REG_BREAK2 0x18
	69	#define CH341_NBREAK_BITS_REG1 0x01
	70	#define CH341_NBREAK_BITS_REG2 0x40
	71
	72
6ce76104 FK	73	static int debug;
6ce76104 FK	74
7d40d7e8	75	static const struct usb_device_id id_table[] = {
6ce76104	76	{ USB_DEVICE(0x4348, 0x5523) },
82078234	77	{ USB_DEVICE(0x1a86, 0x7523) },
d0781383	78	{ USB_DEVICE(0x1a86, 0x5523) },
6ce76104 FK	79	{ },
	80	};
	81	MODULE_DEVICE_TABLE(usb, id_table);
	82
	83	struct ch341_private {
664d5df9 WC	84	spinlock_t lock; /* access lock */
	85	wait_queue_head_t delta_msr_wait; /* wait queue for modem status */
	86	unsigned baud_rate; /* set baud rate */
	87	u8 line_control; /* set line control value RTS/DTR */
	88	u8 line_status; /* active status of modem control inputs */
	89	u8 multi_status_change; /* status changed multiple since last call */
6ce76104 FK	90	};
	91
	92	static int ch341_control_out(struct usb_device *dev, u8 request,
	93	u16 value, u16 index)
	94	{
	95	int r;
	96	dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT\|0x40,
	97	(int)request, (int)value, (int)index);
	98
	99	r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
	100	USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_OUT,
	101	value, index, NULL, 0, DEFAULT_TIMEOUT);
	102
	103	return r;
	104	}
	105
	106	static int ch341_control_in(struct usb_device *dev,
	107	u8 request, u16 value, u16 index,
	108	char *buf, unsigned bufsize)
	109	{
	110	int r;
	111	dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN\|0x40,
	112	(int)request, (int)value, (int)index, buf, (int)bufsize);
	113
	114	r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
	115	USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_IN,
	116	value, index, buf, bufsize, DEFAULT_TIMEOUT);
	117	return r;
	118	}
	119
93b6497d AB	120	static int ch341_set_baudrate(struct usb_device *dev,
93b6497d AB	121	struct ch341_private *priv)
6ce76104 FK	122	{
	123	short a, b;
	124	int r;
664d5df9 WC	125	unsigned long factor;
664d5df9 WC	126	short divisor;
6ce76104 FK	127
6ce76104 FK	128	dbg("ch341_set_baudrate(%d)", priv->baud_rate);
664d5df9 WC	129
664d5df9 WC	130	if (!priv->baud_rate)
6ce76104	131	return -EINVAL;
664d5df9 WC	132	factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
	133	divisor = CH341_BAUDBASE_DIVMAX;
	134
	135	while ((factor > 0xfff0) && divisor) {
	136	factor >>= 3;
	137	divisor--;
6ce76104 FK	138	}
6ce76104 FK	139
664d5df9 WC	140	if (factor > 0xfff0)
	141	return -EINVAL;
	142
	143	factor = 0x10000 - factor;
	144	a = (factor & 0xff00) \| divisor;
	145	b = factor & 0xff;
	146
6ce76104 FK	147	r = ch341_control_out(dev, 0x9a, 0x1312, a);
	148	if (!r)
	149	r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
	150
	151	return r;
	152	}
	153
664d5df9	154	static int ch341_set_handshake(struct usb_device *dev, u8 control)
6ce76104	155	{
664d5df9 WC	156	dbg("ch341_set_handshake(0x%02x)", control);
664d5df9 WC	157	return ch341_control_out(dev, 0xa4, ~control, 0);
6ce76104 FK	158	}
6ce76104 FK	159
664d5df9	160	static int ch341_get_status(struct usb_device dev, struct ch341_private priv)
6ce76104 FK	161	{
	162	char *buffer;
	163	int r;
	164	const unsigned size = 8;
664d5df9	165	unsigned long flags;
6ce76104 FK	166
	167	dbg("ch341_get_status()");
	168
	169	buffer = kmalloc(size, GFP_KERNEL);
	170	if (!buffer)
	171	return -ENOMEM;
	172
	173	r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
c4d0f8cb	174	if (r < 0)
6ce76104 FK	175	goto out;
6ce76104 FK	176
664d5df9 WC	177	/* setup the private status if available */
	178	if (r == 2) {
	179	r = 0;
	180	spin_lock_irqsave(&priv->lock, flags);
	181	priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
	182	priv->multi_status_change = 0;
	183	spin_unlock_irqrestore(&priv->lock, flags);
	184	} else
	185	r = -EPROTO;
6ce76104 FK	186
	187	out: kfree(buffer);
	188	return r;
	189	}
	190
	191	/* -------------------------------------------------------------------------- */
	192
93b6497d	193	static int ch341_configure(struct usb_device dev, struct ch341_private priv)
6ce76104 FK	194	{
	195	char *buffer;
	196	int r;
	197	const unsigned size = 8;
	198
	199	dbg("ch341_configure()");
	200
	201	buffer = kmalloc(size, GFP_KERNEL);
	202	if (!buffer)
	203	return -ENOMEM;
	204
	205	/* expect two bytes 0x27 0x00 */
	206	r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
	207	if (r < 0)
	208	goto out;
	209
	210	r = ch341_control_out(dev, 0xa1, 0, 0);
	211	if (r < 0)
	212	goto out;
	213
	214	r = ch341_set_baudrate(dev, priv);
	215	if (r < 0)
	216	goto out;
	217
	218	/* expect two bytes 0x56 0x00 */
	219	r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
	220	if (r < 0)
	221	goto out;
	222
	223	r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
	224	if (r < 0)
	225	goto out;
	226
	227	/* expect 0xff 0xee */
664d5df9	228	r = ch341_get_status(dev, priv);
6ce76104 FK	229	if (r < 0)
	230	goto out;
	231
	232	r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
	233	if (r < 0)
	234	goto out;
	235
	236	r = ch341_set_baudrate(dev, priv);
	237	if (r < 0)
	238	goto out;
	239
664d5df9	240	r = ch341_set_handshake(dev, priv->line_control);
6ce76104 FK	241	if (r < 0)
	242	goto out;
	243
	244	/* expect 0x9f 0xee */
664d5df9	245	r = ch341_get_status(dev, priv);
6ce76104 FK	246
	247	out: kfree(buffer);
	248	return r;
	249	}
	250
	251	/* allocate private data */
	252	static int ch341_attach(struct usb_serial *serial)
	253	{
	254	struct ch341_private *priv;
	255	int r;
	256
	257	dbg("ch341_attach()");
	258
	259	/* private data */
	260	priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
	261	if (!priv)
	262	return -ENOMEM;
	263
664d5df9 WC	264	spin_lock_init(&priv->lock);
664d5df9 WC	265	init_waitqueue_head(&priv->delta_msr_wait);
6ce76104	266	priv->baud_rate = DEFAULT_BAUD_RATE;
664d5df9	267	priv->line_control = CH341_BIT_RTS \| CH341_BIT_DTR;
6ce76104 FK	268
	269	r = ch341_configure(serial->dev, priv);
	270	if (r < 0)
	271	goto error;
	272
	273	usb_set_serial_port_data(serial->port[0], priv);
	274	return 0;
	275
	276	error: kfree(priv);
	277	return r;
	278	}
	279
335f8514 AC	280	static int ch341_carrier_raised(struct usb_serial_port *port)
	281	{
	282	struct ch341_private *priv = usb_get_serial_port_data(port);
	283	if (priv->line_status & CH341_BIT_DCD)
	284	return 1;
	285	return 0;
	286	}
	287
	288	static void ch341_dtr_rts(struct usb_serial_port *port, int on)
664d5df9 WC	289	{
	290	struct ch341_private *priv = usb_get_serial_port_data(port);
	291	unsigned long flags;
664d5df9	292
335f8514 AC	293	dbg("%s - port %d", __func__, port->number);
	294	/* drop DTR and RTS */
	295	spin_lock_irqsave(&priv->lock, flags);
	296	if (on)
	297	priv->line_control \|= CH341_BIT_RTS \| CH341_BIT_DTR;
	298	else
	299	priv->line_control &= ~(CH341_BIT_RTS \| CH341_BIT_DTR);
	300	spin_unlock_irqrestore(&priv->lock, flags);
	301	ch341_set_handshake(port->serial->dev, priv->line_control);
	302	wake_up_interruptible(&priv->delta_msr_wait);
	303	}
	304
	305	static void ch341_close(struct usb_serial_port *port)
	306	{
664d5df9 WC	307	dbg("%s - port %d", __func__, port->number);
664d5df9 WC	308
f26788da	309	usb_serial_generic_close(port);
664d5df9	310	usb_kill_urb(port->interrupt_in_urb);
664d5df9 WC	311	}
	312
	313
6ce76104	314	/* open this device, set default parameters */
a509a7e4	315	static int ch341_open(struct tty_struct tty, struct usb_serial_port port)
6ce76104 FK	316	{
	317	struct usb_serial *serial = port->serial;
	318	struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
	319	int r;
	320
	321	dbg("ch341_open()");
	322
	323	priv->baud_rate = DEFAULT_BAUD_RATE;
6ce76104 FK	324
	325	r = ch341_configure(serial->dev, priv);
	326	if (r)
	327	goto out;
	328
664d5df9	329	r = ch341_set_handshake(serial->dev, priv->line_control);
6ce76104 FK	330	if (r)
	331	goto out;
	332
	333	r = ch341_set_baudrate(serial->dev, priv);
	334	if (r)
	335	goto out;
	336
664d5df9 WC	337	dbg("%s - submitting interrupt urb", __func__);
	338	port->interrupt_in_urb->dev = serial->dev;
	339	r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
	340	if (r) {
	341	dev_err(&port->dev, "%s - failed submitting interrupt urb,"
	342	" error %d\n", __func__, r);
335f8514	343	ch341_close(port);
664d5df9 WC	344	return -EPROTO;
	345	}
	346
a509a7e4	347	r = usb_serial_generic_open(tty, port);
6ce76104 FK	348
	349	out: return r;
	350	}
	351
	352	/* Old_termios contains the original termios settings and
	353	* tty->termios contains the new setting to be used.
	354	*/
95da310e AC	355	static void ch341_set_termios(struct tty_struct *tty,
95da310e AC	356	struct usb_serial_port port, struct ktermios old_termios)
6ce76104 FK	357	{
6ce76104 FK	358	struct ch341_private *priv = usb_get_serial_port_data(port);
6ce76104	359	unsigned baud_rate;
664d5df9	360	unsigned long flags;
6ce76104 FK	361
	362	dbg("ch341_set_termios()");
	363
6ce76104 FK	364	baud_rate = tty_get_baud_rate(tty);
6ce76104 FK	365
664d5df9 WC	366	priv->baud_rate = baud_rate;
	367
	368	if (baud_rate) {
	369	spin_lock_irqsave(&priv->lock, flags);
	370	priv->line_control \|= (CH341_BIT_DTR \| CH341_BIT_RTS);
	371	spin_unlock_irqrestore(&priv->lock, flags);
	372	ch341_set_baudrate(port->serial->dev, priv);
	373	} else {
	374	spin_lock_irqsave(&priv->lock, flags);
	375	priv->line_control &= ~(CH341_BIT_DTR \| CH341_BIT_RTS);
	376	spin_unlock_irqrestore(&priv->lock, flags);
6ce76104 FK	377	}
6ce76104 FK	378
664d5df9	379	ch341_set_handshake(port->serial->dev, priv->line_control);
6ce76104 FK	380
	381	/* Unimplemented:
	382	* (cflag & CSIZE) : data bits [5, 8]
	383	* (cflag & PARENB) : parity {NONE, EVEN, ODD}
	384	* (cflag & CSTOPB) : stop bits [1, 2]
	385	*/
664d5df9 WC	386	}
664d5df9 WC	387
492896f0 TS	388	static void ch341_break_ctl(struct tty_struct *tty, int break_state)
	389	{
	390	const uint16_t ch341_break_reg =
	391	CH341_REG_BREAK1 \| ((uint16_t) CH341_REG_BREAK2 << 8);
	392	struct usb_serial_port *port = tty->driver_data;
	393	int r;
	394	uint16_t reg_contents;
f2b5cc83	395	uint8_t *break_reg;
492896f0 TS	396
	397	dbg("%s()", __func__);
	398
f2b5cc83 JH	399	break_reg = kmalloc(2, GFP_KERNEL);
	400	if (!break_reg) {
	401	dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
	402	return;
	403	}
	404
492896f0	405	r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
f2b5cc83	406	ch341_break_reg, 0, break_reg, 2);
492896f0	407	if (r < 0) {
6a9b15fe JH	408	dev_err(&port->dev, "%s - USB control read error (%d)\n",
6a9b15fe JH	409	__func__, r);
f2b5cc83	410	goto out;
492896f0 TS	411	}
	412	dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
	413	__func__, break_reg[0], break_reg[1]);
	414	if (break_state != 0) {
	415	dbg("%s - Enter break state requested", __func__);
	416	break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
	417	break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
	418	} else {
	419	dbg("%s - Leave break state requested", __func__);
	420	break_reg[0] \|= CH341_NBREAK_BITS_REG1;
	421	break_reg[1] \|= CH341_NBREAK_BITS_REG2;
	422	}
	423	dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
	424	__func__, break_reg[0], break_reg[1]);
5be796f0	425	reg_contents = get_unaligned_le16(break_reg);
492896f0 TS	426	r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
	427	ch341_break_reg, reg_contents);
	428	if (r < 0)
6a9b15fe JH	429	dev_err(&port->dev, "%s - USB control write error (%d)\n",
6a9b15fe JH	430	__func__, r);
f2b5cc83 JH	431	out:
f2b5cc83 JH	432	kfree(break_reg);
492896f0 TS	433	}
492896f0 TS	434
20b9d177	435	static int ch341_tiocmset(struct tty_struct *tty,
664d5df9 WC	436	unsigned int set, unsigned int clear)
	437	{
	438	struct usb_serial_port *port = tty->driver_data;
	439	struct ch341_private *priv = usb_get_serial_port_data(port);
	440	unsigned long flags;
	441	u8 control;
	442
	443	spin_lock_irqsave(&priv->lock, flags);
	444	if (set & TIOCM_RTS)
	445	priv->line_control \|= CH341_BIT_RTS;
	446	if (set & TIOCM_DTR)
	447	priv->line_control \|= CH341_BIT_DTR;
	448	if (clear & TIOCM_RTS)
	449	priv->line_control &= ~CH341_BIT_RTS;
	450	if (clear & TIOCM_DTR)
	451	priv->line_control &= ~CH341_BIT_DTR;
	452	control = priv->line_control;
	453	spin_unlock_irqrestore(&priv->lock, flags);
	454
	455	return ch341_set_handshake(port->serial->dev, control);
	456	}
	457
	458	static void ch341_read_int_callback(struct urb *urb)
	459	{
	460	struct usb_serial_port port = (struct usb_serial_port ) urb->context;
	461	unsigned char *data = urb->transfer_buffer;
	462	unsigned int actual_length = urb->actual_length;
	463	int status;
	464
	465	dbg("%s (%d)", __func__, port->number);
	466
	467	switch (urb->status) {
	468	case 0:
	469	/* success */
	470	break;
	471	case -ECONNRESET:
	472	case -ENOENT:
	473	case -ESHUTDOWN:
	474	/* this urb is terminated, clean up */
	475	dbg("%s - urb shutting down with status: %d", __func__,
	476	urb->status);
	477	return;
	478	default:
	479	dbg("%s - nonzero urb status received: %d", __func__,
	480	urb->status);
	481	goto exit;
	482	}
	483
	484	usb_serial_debug_data(debug, &port->dev, __func__,
	485	urb->actual_length, urb->transfer_buffer);
	486
	487	if (actual_length >= 4) {
	488	struct ch341_private *priv = usb_get_serial_port_data(port);
	489	unsigned long flags;
d14fc1a7	490	u8 prev_line_status = priv->line_status;
664d5df9 WC	491
	492	spin_lock_irqsave(&priv->lock, flags);
	493	priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
	494	if ((data[1] & CH341_MULT_STAT))
	495	priv->multi_status_change = 1;
	496	spin_unlock_irqrestore(&priv->lock, flags);
d14fc1a7 LP	497
	498	if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
	499	struct tty_struct *tty = tty_port_tty_get(&port->port);
	500	if (tty)
	501	usb_serial_handle_dcd_change(port, tty,
	502	priv->line_status & CH341_BIT_DCD);
	503	tty_kref_put(tty);
	504	}
	505
664d5df9 WC	506	wake_up_interruptible(&priv->delta_msr_wait);
	507	}
	508
	509	exit:
	510	status = usb_submit_urb(urb, GFP_ATOMIC);
	511	if (status)
	512	dev_err(&urb->dev->dev,
	513	"%s - usb_submit_urb failed with result %d\n",
	514	__func__, status);
	515	}
	516
	517	static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
	518	{
	519	struct ch341_private *priv = usb_get_serial_port_data(port);
	520	unsigned long flags;
	521	u8 prevstatus;
	522	u8 status;
	523	u8 changed;
	524	u8 multi_change = 0;
	525
	526	spin_lock_irqsave(&priv->lock, flags);
	527	prevstatus = priv->line_status;
	528	priv->multi_status_change = 0;
	529	spin_unlock_irqrestore(&priv->lock, flags);
	530
	531	while (!multi_change) {
	532	interruptible_sleep_on(&priv->delta_msr_wait);
	533	/* see if a signal did it */
	534	if (signal_pending(current))
	535	return -ERESTARTSYS;
	536
	537	spin_lock_irqsave(&priv->lock, flags);
	538	status = priv->line_status;
	539	multi_change = priv->multi_status_change;
	540	spin_unlock_irqrestore(&priv->lock, flags);
	541
	542	changed = prevstatus ^ status;
	543
	544	if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) \|\|
	545	((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) \|\|
	546	((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) \|\|
	547	((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
	548	return 0;
	549	}
	550	prevstatus = status;
	551	}
	552
	553	return 0;
	554	}
	555
00a0d0d6	556	static int ch341_ioctl(struct tty_struct *tty,
664d5df9 WC	557	unsigned int cmd, unsigned long arg)
	558	{
	559	struct usb_serial_port *port = tty->driver_data;
	560	dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
	561
	562	switch (cmd) {
	563	case TIOCMIWAIT:
	564	dbg("%s (%d) TIOCMIWAIT", __func__, port->number);
	565	return wait_modem_info(port, arg);
	566
	567	default:
	568	dbg("%s not supported = 0x%04x", __func__, cmd);
	569	break;
	570	}
	571
	572	return -ENOIOCTLCMD;
	573	}
	574
60b33c13	575	static int ch341_tiocmget(struct tty_struct *tty)
664d5df9 WC	576	{
	577	struct usb_serial_port *port = tty->driver_data;
	578	struct ch341_private *priv = usb_get_serial_port_data(port);
	579	unsigned long flags;
	580	u8 mcr;
	581	u8 status;
	582	unsigned int result;
	583
	584	dbg("%s (%d)", __func__, port->number);
	585
	586	spin_lock_irqsave(&priv->lock, flags);
	587	mcr = priv->line_control;
	588	status = priv->line_status;
	589	spin_unlock_irqrestore(&priv->lock, flags);
	590
	591	result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
	592	\| ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
	593	\| ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
	594	\| ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
	595	\| ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
	596	\| ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
	597
	598	dbg("%s - result = %x", __func__, result);
73f59308	599
664d5df9	600	return result;
6ce76104 FK	601	}
6ce76104 FK	602
1ded7ea4 ML	603
	604	static int ch341_reset_resume(struct usb_interface *intf)
	605	{
	606	struct usb_device *dev = interface_to_usbdev(intf);
	607	struct usb_serial *serial = NULL;
	608	struct ch341_private *priv;
	609
	610	serial = usb_get_intfdata(intf);
	611	priv = usb_get_serial_port_data(serial->port[0]);
	612
	613	/reconfigure ch341 serial port after bus-reset/
	614	ch341_configure(dev, priv);
	615
	616	usb_serial_resume(intf);
	617
	618	return 0;
	619	}
	620
6ce76104 FK	621	static struct usb_driver ch341_driver = {
	622	.name = "ch341",
	623	.probe = usb_serial_probe,
	624	.disconnect = usb_serial_disconnect,
1ded7ea4 ML	625	.suspend = usb_serial_suspend,
	626	.resume = usb_serial_resume,
	627	.reset_resume = ch341_reset_resume,
6ce76104 FK	628	.id_table = id_table,
6ce76104 FK	629	.no_dynamic_id = 1,
1ded7ea4	630	.supports_autosuspend = 1,
6ce76104 FK	631	};
	632
	633	static struct usb_serial_driver ch341_device = {
	634	.driver = {
	635	.owner = THIS_MODULE,
	636	.name = "ch341-uart",
	637	},
664d5df9 WC	638	.id_table = id_table,
	639	.usb_driver = &ch341_driver,
	640	.num_ports = 1,
	641	.open = ch341_open,
335f8514 AC	642	.dtr_rts = ch341_dtr_rts,
335f8514 AC	643	.carrier_raised = ch341_carrier_raised,
664d5df9 WC	644	.close = ch341_close,
	645	.ioctl = ch341_ioctl,
	646	.set_termios = ch341_set_termios,
492896f0	647	.break_ctl = ch341_break_ctl,
664d5df9 WC	648	.tiocmget = ch341_tiocmget,
	649	.tiocmset = ch341_tiocmset,
	650	.read_int_callback = ch341_read_int_callback,
	651	.attach = ch341_attach,
6ce76104 FK	652	};
	653
	654	static int __init ch341_init(void)
	655	{
	656	int retval;
	657
	658	retval = usb_serial_register(&ch341_device);
	659	if (retval)
	660	return retval;
	661	retval = usb_register(&ch341_driver);
	662	if (retval)
	663	usb_serial_deregister(&ch341_device);
	664	return retval;
	665	}
	666
	667	static void __exit ch341_exit(void)
	668	{
	669	usb_deregister(&ch341_driver);
	670	usb_serial_deregister(&ch341_device);
	671	}
	672
	673	module_init(ch341_init);
	674	module_exit(ch341_exit);
	675	MODULE_LICENSE("GPL");
	676
	677	module_param(debug, bool, S_IRUGO \| S_IWUSR);
	678	MODULE_PARM_DESC(debug, "Debug enabled or not");
	679
	680	/* EOF ch341.c */