[linux-block.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) },
	{ },
};
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, struct file *file,
			  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 usb_serial_port *port, struct file *file,*/
static int ch341_ioctl(struct tty_struct *tty, struct file *file,
			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 file *file)
{
	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) },
6ce76104 FK	78	{ },
	79	};
	80	MODULE_DEVICE_TABLE(usb, id_table);
	81
	82	struct ch341_private {
664d5df9 WC	83	spinlock_t lock; /* access lock */
	84	wait_queue_head_t delta_msr_wait; /* wait queue for modem status */
	85	unsigned baud_rate; /* set baud rate */
	86	u8 line_control; /* set line control value RTS/DTR */
	87	u8 line_status; /* active status of modem control inputs */
	88	u8 multi_status_change; /* status changed multiple since last call */
6ce76104 FK	89	};
	90
	91	static int ch341_control_out(struct usb_device *dev, u8 request,
	92	u16 value, u16 index)
	93	{
	94	int r;
	95	dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT\|0x40,
	96	(int)request, (int)value, (int)index);
	97
	98	r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
	99	USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_OUT,
	100	value, index, NULL, 0, DEFAULT_TIMEOUT);
	101
	102	return r;
	103	}
	104
	105	static int ch341_control_in(struct usb_device *dev,
	106	u8 request, u16 value, u16 index,
	107	char *buf, unsigned bufsize)
	108	{
	109	int r;
	110	dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN\|0x40,
	111	(int)request, (int)value, (int)index, buf, (int)bufsize);
	112
	113	r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
	114	USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_IN,
	115	value, index, buf, bufsize, DEFAULT_TIMEOUT);
	116	return r;
	117	}
	118
93b6497d AB	119	static int ch341_set_baudrate(struct usb_device *dev,
93b6497d AB	120	struct ch341_private *priv)
6ce76104 FK	121	{
	122	short a, b;
	123	int r;
664d5df9 WC	124	unsigned long factor;
664d5df9 WC	125	short divisor;
6ce76104 FK	126
6ce76104 FK	127	dbg("ch341_set_baudrate(%d)", priv->baud_rate);
664d5df9 WC	128
664d5df9 WC	129	if (!priv->baud_rate)
6ce76104	130	return -EINVAL;
664d5df9 WC	131	factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
	132	divisor = CH341_BAUDBASE_DIVMAX;
	133
	134	while ((factor > 0xfff0) && divisor) {
	135	factor >>= 3;
	136	divisor--;
6ce76104 FK	137	}
6ce76104 FK	138
664d5df9 WC	139	if (factor > 0xfff0)
	140	return -EINVAL;
	141
	142	factor = 0x10000 - factor;
	143	a = (factor & 0xff00) \| divisor;
	144	b = factor & 0xff;
	145
6ce76104 FK	146	r = ch341_control_out(dev, 0x9a, 0x1312, a);
	147	if (!r)
	148	r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
	149
	150	return r;
	151	}
	152
664d5df9	153	static int ch341_set_handshake(struct usb_device *dev, u8 control)
6ce76104	154	{
664d5df9 WC	155	dbg("ch341_set_handshake(0x%02x)", control);
664d5df9 WC	156	return ch341_control_out(dev, 0xa4, ~control, 0);
6ce76104 FK	157	}
6ce76104 FK	158
664d5df9	159	static int ch341_get_status(struct usb_device dev, struct ch341_private priv)
6ce76104 FK	160	{
	161	char *buffer;
	162	int r;
	163	const unsigned size = 8;
664d5df9	164	unsigned long flags;
6ce76104 FK	165
	166	dbg("ch341_get_status()");
	167
	168	buffer = kmalloc(size, GFP_KERNEL);
	169	if (!buffer)
	170	return -ENOMEM;
	171
	172	r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
c4d0f8cb	173	if (r < 0)
6ce76104 FK	174	goto out;
6ce76104 FK	175
664d5df9 WC	176	/* setup the private status if available */
	177	if (r == 2) {
	178	r = 0;
	179	spin_lock_irqsave(&priv->lock, flags);
	180	priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
	181	priv->multi_status_change = 0;
	182	spin_unlock_irqrestore(&priv->lock, flags);
	183	} else
	184	r = -EPROTO;
6ce76104 FK	185
	186	out: kfree(buffer);
	187	return r;
	188	}
	189
	190	/* -------------------------------------------------------------------------- */
	191
93b6497d	192	static int ch341_configure(struct usb_device dev, struct ch341_private priv)
6ce76104 FK	193	{
	194	char *buffer;
	195	int r;
	196	const unsigned size = 8;
	197
	198	dbg("ch341_configure()");
	199
	200	buffer = kmalloc(size, GFP_KERNEL);
	201	if (!buffer)
	202	return -ENOMEM;
	203
	204	/* expect two bytes 0x27 0x00 */
	205	r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
	206	if (r < 0)
	207	goto out;
	208
	209	r = ch341_control_out(dev, 0xa1, 0, 0);
	210	if (r < 0)
	211	goto out;
	212
	213	r = ch341_set_baudrate(dev, priv);
	214	if (r < 0)
	215	goto out;
	216
	217	/* expect two bytes 0x56 0x00 */
	218	r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
	219	if (r < 0)
	220	goto out;
	221
	222	r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
	223	if (r < 0)
	224	goto out;
	225
	226	/* expect 0xff 0xee */
664d5df9	227	r = ch341_get_status(dev, priv);
6ce76104 FK	228	if (r < 0)
	229	goto out;
	230
	231	r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
	232	if (r < 0)
	233	goto out;
	234
	235	r = ch341_set_baudrate(dev, priv);
	236	if (r < 0)
	237	goto out;
	238
664d5df9	239	r = ch341_set_handshake(dev, priv->line_control);
6ce76104 FK	240	if (r < 0)
	241	goto out;
	242
	243	/* expect 0x9f 0xee */
664d5df9	244	r = ch341_get_status(dev, priv);
6ce76104 FK	245
	246	out: kfree(buffer);
	247	return r;
	248	}
	249
	250	/* allocate private data */
	251	static int ch341_attach(struct usb_serial *serial)
	252	{
	253	struct ch341_private *priv;
	254	int r;
	255
	256	dbg("ch341_attach()");
	257
	258	/* private data */
	259	priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
	260	if (!priv)
	261	return -ENOMEM;
	262
664d5df9 WC	263	spin_lock_init(&priv->lock);
664d5df9 WC	264	init_waitqueue_head(&priv->delta_msr_wait);
6ce76104	265	priv->baud_rate = DEFAULT_BAUD_RATE;
664d5df9	266	priv->line_control = CH341_BIT_RTS \| CH341_BIT_DTR;
6ce76104 FK	267
	268	r = ch341_configure(serial->dev, priv);
	269	if (r < 0)
	270	goto error;
	271
	272	usb_set_serial_port_data(serial->port[0], priv);
	273	return 0;
	274
	275	error: kfree(priv);
	276	return r;
	277	}
	278
335f8514 AC	279	static int ch341_carrier_raised(struct usb_serial_port *port)
	280	{
	281	struct ch341_private *priv = usb_get_serial_port_data(port);
	282	if (priv->line_status & CH341_BIT_DCD)
	283	return 1;
	284	return 0;
	285	}
	286
	287	static void ch341_dtr_rts(struct usb_serial_port *port, int on)
664d5df9 WC	288	{
	289	struct ch341_private *priv = usb_get_serial_port_data(port);
	290	unsigned long flags;
664d5df9	291
335f8514 AC	292	dbg("%s - port %d", __func__, port->number);
	293	/* drop DTR and RTS */
	294	spin_lock_irqsave(&priv->lock, flags);
	295	if (on)
	296	priv->line_control \|= CH341_BIT_RTS \| CH341_BIT_DTR;
	297	else
	298	priv->line_control &= ~(CH341_BIT_RTS \| CH341_BIT_DTR);
	299	spin_unlock_irqrestore(&priv->lock, flags);
	300	ch341_set_handshake(port->serial->dev, priv->line_control);
	301	wake_up_interruptible(&priv->delta_msr_wait);
	302	}
	303
	304	static void ch341_close(struct usb_serial_port *port)
	305	{
664d5df9 WC	306	dbg("%s - port %d", __func__, port->number);
664d5df9 WC	307
f26788da	308	usb_serial_generic_close(port);
664d5df9	309	usb_kill_urb(port->interrupt_in_urb);
664d5df9 WC	310	}
	311
	312
6ce76104	313	/* open this device, set default parameters */
a509a7e4	314	static int ch341_open(struct tty_struct tty, struct usb_serial_port port)
6ce76104 FK	315	{
	316	struct usb_serial *serial = port->serial;
	317	struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
	318	int r;
	319
	320	dbg("ch341_open()");
	321
	322	priv->baud_rate = DEFAULT_BAUD_RATE;
6ce76104 FK	323
	324	r = ch341_configure(serial->dev, priv);
	325	if (r)
	326	goto out;
	327
664d5df9	328	r = ch341_set_handshake(serial->dev, priv->line_control);
6ce76104 FK	329	if (r)
	330	goto out;
	331
	332	r = ch341_set_baudrate(serial->dev, priv);
	333	if (r)
	334	goto out;
	335
664d5df9 WC	336	dbg("%s - submitting interrupt urb", __func__);
	337	port->interrupt_in_urb->dev = serial->dev;
	338	r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
	339	if (r) {
	340	dev_err(&port->dev, "%s - failed submitting interrupt urb,"
	341	" error %d\n", __func__, r);
335f8514	342	ch341_close(port);
664d5df9 WC	343	return -EPROTO;
	344	}
	345
a509a7e4	346	r = usb_serial_generic_open(tty, port);
6ce76104 FK	347
	348	out: return r;
	349	}
	350
	351	/* Old_termios contains the original termios settings and
	352	* tty->termios contains the new setting to be used.
	353	*/
95da310e AC	354	static void ch341_set_termios(struct tty_struct *tty,
95da310e AC	355	struct usb_serial_port port, struct ktermios old_termios)
6ce76104 FK	356	{
6ce76104 FK	357	struct ch341_private *priv = usb_get_serial_port_data(port);
6ce76104	358	unsigned baud_rate;
664d5df9	359	unsigned long flags;
6ce76104 FK	360
	361	dbg("ch341_set_termios()");
	362
6ce76104 FK	363	baud_rate = tty_get_baud_rate(tty);
6ce76104 FK	364
664d5df9 WC	365	priv->baud_rate = baud_rate;
	366
	367	if (baud_rate) {
	368	spin_lock_irqsave(&priv->lock, flags);
	369	priv->line_control \|= (CH341_BIT_DTR \| CH341_BIT_RTS);
	370	spin_unlock_irqrestore(&priv->lock, flags);
	371	ch341_set_baudrate(port->serial->dev, priv);
	372	} else {
	373	spin_lock_irqsave(&priv->lock, flags);
	374	priv->line_control &= ~(CH341_BIT_DTR \| CH341_BIT_RTS);
	375	spin_unlock_irqrestore(&priv->lock, flags);
6ce76104 FK	376	}
6ce76104 FK	377
664d5df9	378	ch341_set_handshake(port->serial->dev, priv->line_control);
6ce76104 FK	379
	380	/* Unimplemented:
	381	* (cflag & CSIZE) : data bits [5, 8]
	382	* (cflag & PARENB) : parity {NONE, EVEN, ODD}
	383	* (cflag & CSTOPB) : stop bits [1, 2]
	384	*/
664d5df9 WC	385	}
664d5df9 WC	386
492896f0 TS	387	static void ch341_break_ctl(struct tty_struct *tty, int break_state)
	388	{
	389	const uint16_t ch341_break_reg =
	390	CH341_REG_BREAK1 \| ((uint16_t) CH341_REG_BREAK2 << 8);
	391	struct usb_serial_port *port = tty->driver_data;
	392	int r;
	393	uint16_t reg_contents;
f2b5cc83	394	uint8_t *break_reg;
492896f0 TS	395
	396	dbg("%s()", __func__);
	397
f2b5cc83 JH	398	break_reg = kmalloc(2, GFP_KERNEL);
	399	if (!break_reg) {
	400	dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
	401	return;
	402	}
	403
492896f0	404	r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
f2b5cc83	405	ch341_break_reg, 0, break_reg, 2);
492896f0	406	if (r < 0) {
6a9b15fe JH	407	dev_err(&port->dev, "%s - USB control read error (%d)\n",
6a9b15fe JH	408	__func__, r);
f2b5cc83	409	goto out;
492896f0 TS	410	}
	411	dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
	412	__func__, break_reg[0], break_reg[1]);
	413	if (break_state != 0) {
	414	dbg("%s - Enter break state requested", __func__);
	415	break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
	416	break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
	417	} else {
	418	dbg("%s - Leave break state requested", __func__);
	419	break_reg[0] \|= CH341_NBREAK_BITS_REG1;
	420	break_reg[1] \|= CH341_NBREAK_BITS_REG2;
	421	}
	422	dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
	423	__func__, break_reg[0], break_reg[1]);
5be796f0	424	reg_contents = get_unaligned_le16(break_reg);
492896f0 TS	425	r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
	426	ch341_break_reg, reg_contents);
	427	if (r < 0)
6a9b15fe JH	428	dev_err(&port->dev, "%s - USB control write error (%d)\n",
6a9b15fe JH	429	__func__, r);
f2b5cc83 JH	430	out:
f2b5cc83 JH	431	kfree(break_reg);
492896f0 TS	432	}
492896f0 TS	433
664d5df9 WC	434	static int ch341_tiocmset(struct tty_struct tty, struct file file,
	435	unsigned int set, unsigned int clear)
	436	{
	437	struct usb_serial_port *port = tty->driver_data;
	438	struct ch341_private *priv = usb_get_serial_port_data(port);
	439	unsigned long flags;
	440	u8 control;
	441
	442	spin_lock_irqsave(&priv->lock, flags);
	443	if (set & TIOCM_RTS)
	444	priv->line_control \|= CH341_BIT_RTS;
	445	if (set & TIOCM_DTR)
	446	priv->line_control \|= CH341_BIT_DTR;
	447	if (clear & TIOCM_RTS)
	448	priv->line_control &= ~CH341_BIT_RTS;
	449	if (clear & TIOCM_DTR)
	450	priv->line_control &= ~CH341_BIT_DTR;
	451	control = priv->line_control;
	452	spin_unlock_irqrestore(&priv->lock, flags);
	453
	454	return ch341_set_handshake(port->serial->dev, control);
	455	}
	456
	457	static void ch341_read_int_callback(struct urb *urb)
	458	{
	459	struct usb_serial_port port = (struct usb_serial_port ) urb->context;
	460	unsigned char *data = urb->transfer_buffer;
	461	unsigned int actual_length = urb->actual_length;
	462	int status;
	463
	464	dbg("%s (%d)", __func__, port->number);
	465
	466	switch (urb->status) {
	467	case 0:
	468	/* success */
	469	break;
	470	case -ECONNRESET:
	471	case -ENOENT:
	472	case -ESHUTDOWN:
	473	/* this urb is terminated, clean up */
	474	dbg("%s - urb shutting down with status: %d", __func__,
	475	urb->status);
	476	return;
	477	default:
	478	dbg("%s - nonzero urb status received: %d", __func__,
	479	urb->status);
	480	goto exit;
	481	}
	482
	483	usb_serial_debug_data(debug, &port->dev, __func__,
	484	urb->actual_length, urb->transfer_buffer);
	485
	486	if (actual_length >= 4) {
	487	struct ch341_private *priv = usb_get_serial_port_data(port);
	488	unsigned long flags;
d14fc1a7	489	u8 prev_line_status = priv->line_status;
664d5df9 WC	490
	491	spin_lock_irqsave(&priv->lock, flags);
	492	priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
	493	if ((data[1] & CH341_MULT_STAT))
	494	priv->multi_status_change = 1;
	495	spin_unlock_irqrestore(&priv->lock, flags);
d14fc1a7 LP	496
	497	if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
	498	struct tty_struct *tty = tty_port_tty_get(&port->port);
	499	if (tty)
	500	usb_serial_handle_dcd_change(port, tty,
	501	priv->line_status & CH341_BIT_DCD);
	502	tty_kref_put(tty);
	503	}
	504
664d5df9 WC	505	wake_up_interruptible(&priv->delta_msr_wait);
	506	}
	507
	508	exit:
	509	status = usb_submit_urb(urb, GFP_ATOMIC);
	510	if (status)
	511	dev_err(&urb->dev->dev,
	512	"%s - usb_submit_urb failed with result %d\n",
	513	__func__, status);
	514	}
	515
	516	static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
	517	{
	518	struct ch341_private *priv = usb_get_serial_port_data(port);
	519	unsigned long flags;
	520	u8 prevstatus;
	521	u8 status;
	522	u8 changed;
	523	u8 multi_change = 0;
	524
	525	spin_lock_irqsave(&priv->lock, flags);
	526	prevstatus = priv->line_status;
	527	priv->multi_status_change = 0;
	528	spin_unlock_irqrestore(&priv->lock, flags);
	529
	530	while (!multi_change) {
	531	interruptible_sleep_on(&priv->delta_msr_wait);
	532	/* see if a signal did it */
	533	if (signal_pending(current))
	534	return -ERESTARTSYS;
	535
	536	spin_lock_irqsave(&priv->lock, flags);
	537	status = priv->line_status;
	538	multi_change = priv->multi_status_change;
	539	spin_unlock_irqrestore(&priv->lock, flags);
	540
	541	changed = prevstatus ^ status;
	542
	543	if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) \|\|
	544	((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) \|\|
	545	((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) \|\|
	546	((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
	547	return 0;
	548	}
	549	prevstatus = status;
	550	}
	551
	552	return 0;
	553	}
	554
	555	/static int ch341_ioctl(struct usb_serial_port port, struct file file,/
	556	static int ch341_ioctl(struct tty_struct tty, struct file file,
	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
575	static int ch341_tiocmget(struct tty_struct tty, struct file file)
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 */