/* * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk> * * 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/usb.h>#include <linux/usb/serial.h>#include <linux/serial.h>#define DEFAULT_BAUD_RATE 2400#define DEFAULT_TIMEOUT   1000static int debug;static struct usb_device_id id_table [] = {	{ USB_DEVICE(0x4348, 0x5523) },	{ },};MODULE_DEVICE_TABLE(usb, id_table);struct ch341_private {	unsigned baud_rate;	u8 dtr;	u8 rts;};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;	dbg("ch341_set_baudrate(%d)", priv->baud_rate);	switch (priv->baud_rate) {	case 2400:		a = 0xd901;		b = 0x0038;		break;	case 4800:		a = 0x6402;		b = 0x001f;		break;	case 9600:		a = 0xb202;		b = 0x0013;		break;	case 19200:		a = 0xd902;		b = 0x000d;		break;	case 38400:		a = 0x6403;		b = 0x000a;		break;	case 115200:		a = 0xcc03;		b = 0x0008;		break;	default:		return -EINVAL;	}	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,			       struct ch341_private *priv){	dbg("ch341_set_handshake(%d,%d)", priv->dtr, priv->rts);	return ch341_control_out(dev, 0xa4,		~((priv->dtr?1<<5:0)|(priv->rts?1<<6:0)), 0);}static int ch341_get_status(struct usb_device *dev){	char *buffer;	int r;	const unsigned size = 8;	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;	/* Not having the datasheet for the CH341, we ignore the bytes returned	 * from the device. Return error if the device did not respond in time.	 */	r = 0;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);	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);	if (r < 0)		goto out;	/* expect 0x9f 0xee */	r = ch341_get_status(dev);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;	priv->baud_rate = DEFAULT_BAUD_RATE;	priv->dtr = 1;	priv->rts = 1;	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;}/* open this device, set default parameters */static int ch341_open(struct usb_serial_port *port, struct file *filp){	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;	priv->dtr = 1;	priv->rts = 1;	r = ch341_configure(serial->dev, priv);	if (r)		goto out;	r = ch341_set_handshake(serial->dev, priv);	if (r)		goto out;	r = ch341_set_baudrate(serial->dev, priv);	if (r)		goto out;	r = usb_serial_generic_open(port, filp);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 usb_serial_port *port,			      struct ktermios *old_termios){	struct ch341_private *priv = usb_get_serial_port_data(port);	struct tty_struct *tty = port->tty;	unsigned baud_rate;	dbg("ch341_set_termios()");	baud_rate = tty_get_baud_rate(tty);	switch (baud_rate) {	case 2400:	case 4800:	case 9600:	case 19200:	case 38400:	case 115200:		priv->baud_rate = baud_rate;		break;	default:		dbg("Rate %d not supported, using %d",			baud_rate, DEFAULT_BAUD_RATE);		priv->baud_rate = DEFAULT_BAUD_RATE;	}	ch341_set_baudrate(port->serial->dev, priv);	/* Unimplemented:	 * (cflag & CSIZE) : data bits [5, 8]	 * (cflag & PARENB) : parity {NONE, EVEN, ODD}	 * (cflag & CSTOPB) : stop bits [1, 2]	 */	 /* Copy back the old hardware settings */	 tty_termios_copy_hw(tty->termios, old_termios);	 /* And re-encode with the new baud */	 tty_encode_baud_rate(tty, baud_rate, baud_rate);}static struct usb_driver ch341_driver = {	.name		= "ch341",	.probe		= usb_serial_probe,	.disconnect	= usb_serial_disconnect,	.id_table	= id_table,	.no_dynamic_id	= 1,};static struct usb_serial_driver ch341_device = {	.driver = {		.owner	= THIS_MODULE,		.name	= "ch341-uart",	},	.id_table         = id_table,	.usb_driver       = &ch341_driver,	.num_interrupt_in = NUM_DONT_CARE,	.num_bulk_in      = 1,	.num_bulk_out     = 1,	.num_ports        = 1,	.open             = ch341_open,	.set_termios      = ch341_set_termios,	.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 */