ch341.c

ch341在ubuntu下的驱动源码usb转串口的应用开发源码

/*
     * Copyright 2007, Frank A Kingswood <[e-mail]>
     *
     * 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

static 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, 1000);
	
			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, 1000);
			return r;
		}
		
		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;
			}
			
			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);
		}
		
		int ch341_get_status(struct usb_device *dev)
	{
			char *buffer;
			int r = -ENOMEM;
			const unsigned size = 8;
		
				dbg("ch341_get_status()");
			
				buffer = kmalloc(size, GFP_KERNEL);
			if (!buffer)
					goto out;
			
				r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
			/* return value ignored */
				r = 0;
		
			out:	kfree(buffer);
			return r;
		}
		
		/* -------------------------------------------------------------------------- */
		
		int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
	{
			char *buffer;
			int r = -ENOMEM;
			const unsigned size = 8;
		
				dbg("ch341_configure()");
		
				buffer = kmalloc(size, GFP_KERNEL);
			if (!buffer)
					goto out;
		
				/* 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)
					return r;
		
				usb_set_serial_port_data(serial->port[0], priv);
		
				return 0;
		}
		
		/* 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 cflag;
				unsigned baud_rate;
			
					dbg("ch341_set_termios(%p,%p)", port, old_termios);
			
					if (!port->tty || !port->tty->termios)
						return;
			
					cflag = tty->termios->c_cflag;
				
					/* check that they really want us to change something */
					if (old_termios && cflag == old_termios->c_cflag)
						return;
			
					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]
							   	 */
						
						 	return;
					}
					
					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 */