usb转pci连接线的linux驱动程序

/* * 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 1000 static int debug; static struct usb_device_id id_table [] = { { USB_DEVICE(0x4348, 0x5523) }, { USB_DEVICE(0x1a86, 0x7523) }, { }, }; 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; } void tty_termios_copy_hw(struct termios *new, struct termios *old) { /* The bits a dumb device handles in software. Smart devices need to always provide a set_termios method */ new->c_cflag &= HUPCL | CREAD | CLOCAL; new->c_cflag |= old->c_cflag & ~(HUPCL | CREAD | CLOCAL); // new->c_ispeed = old->c_ispeed; // new->c_ospeed = old->c_ospeed; } static int baud_table[] = { 0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800, 500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000, 2500000, 3000000, 3500000, 4000000 }; static int n_baud_table = ARRAY_SIZE(baud_table); void tty_encode_baud_rate(struct termios *termios, speed_t ibaud, speed_t obaud) { int i = 0; int ifound = -1, ofound = -1; int iclose = ibaud/50, oclose = obaud/50; if (obaud == 0) /* CD dropped */ ibaud = 0; /* Clear ibaud to be sure */ // termios->c_ispeed = ibaud; // termios->c_ospeed = obaud; termios->c_cflag &= ~CBAUD; /* * Our goal is to find a close match to the standard baud rate * returned. Walk the baud rate table and if we get a very close * match then report back the speed as a POSIX Bxxxx value by * preference */ do { if (obaud - oclose <= baud_table[i] && obaud + oclose >= baud_table[i]) { if (i > 15) { termios->c_cflag |= i - 15; termios->c_cflag |= CBAUDEX; } else { termios->c_cflag |= i; termios->c_cflag &= ~CBAUDEX; } ofound = i; } if (ibaud - iclose <= baud_table[i] && ibaud + iclose >= baud_table[i]) { /* For the case input == output don't set IBAUD bits if the user didn't do so */ if (ofound == i ) ifound = i; } } while (++i < n_baud_table); /* * If we found no match then use BOTHER if provided or warn * the user their platform maintainer needs to wake up if not. */ if (ifound == -1 || ofound == -1) { static int warned; if (!warned++) printk(KERN_WARNING "tty: Unable to return correct " "speed data as your architecture needs updating.\n"); } } /* 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 termios *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: ca