ftdi_sio.c

標準的linux下rs-232驅動代碼,是2.6內核的.

	clear &= ~set;	/* 'set' takes precedence over 'clear' */
	urb_value = 0;
	if (clear & TIOCM_DTR)
		urb_value |= FTDI_SIO_SET_DTR_LOW;
	if (clear & TIOCM_RTS)
		urb_value |= FTDI_SIO_SET_RTS_LOW;
	if (set & TIOCM_DTR)
		urb_value |= FTDI_SIO_SET_DTR_HIGH;
	if (set & TIOCM_RTS)
		urb_value |= FTDI_SIO_SET_RTS_HIGH;
	rv = usb_control_msg(port->serial->dev,
			       usb_sndctrlpipe(port->serial->dev, 0),
			       FTDI_SIO_SET_MODEM_CTRL_REQUEST,
			       FTDI_SIO_SET_MODEM_CTRL_REQUEST_TYPE,
			       urb_value, priv->interface,
			       buf, 0, WDR_TIMEOUT);

	kfree(buf);
	if (rv < 0) {
		err("%s Error from MODEM_CTRL urb: DTR %s, RTS %s",
				__FUNCTION__,
				(set & TIOCM_DTR) ? "HIGH" :
				(clear & TIOCM_DTR) ? "LOW" : "unchanged",
				(set & TIOCM_RTS) ? "HIGH" :
				(clear & TIOCM_RTS) ? "LOW" : "unchanged");
	} else {
		dbg("%s - DTR %s, RTS %s", __FUNCTION__,
				(set & TIOCM_DTR) ? "HIGH" :
				(clear & TIOCM_DTR) ? "LOW" : "unchanged",
				(set & TIOCM_RTS) ? "HIGH" :
				(clear & TIOCM_RTS) ? "LOW" : "unchanged");
		priv->last_dtr_rts = (priv->last_dtr_rts & ~clear) | set;
	}
	return rv;
}


static __u32 get_ftdi_divisor(struct usb_serial_port * port);


static int change_speed(struct usb_serial_port *port)
{
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	char *buf;
        __u16 urb_value;
	__u16 urb_index;
	__u32 urb_index_value;
	int rv;

	buf = kmalloc(1, GFP_NOIO);
	if (!buf)
		return -ENOMEM;

	urb_index_value = get_ftdi_divisor(port);
	urb_value = (__u16)urb_index_value;
	urb_index = (__u16)(urb_index_value >> 16);
	if ((priv->chip_type == FT2232C) | (priv->chip_type == FT2232H) | (priv->chip_type == FT4232H)) {
		urb_index = (__u16)((urb_index << 8) | priv->interface);
	}

	rv = usb_control_msg(port->serial->dev,
			    usb_sndctrlpipe(port->serial->dev, 0),
			    FTDI_SIO_SET_BAUDRATE_REQUEST,
			    FTDI_SIO_SET_BAUDRATE_REQUEST_TYPE,
			    urb_value, urb_index,
			    buf, 0, WDR_SHORT_TIMEOUT);

	kfree(buf);
	return rv;
}


static __u32 get_ftdi_divisor(struct usb_serial_port * port)
{ /* get_ftdi_divisor */
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	__u32 div_value = 0;
	int div_okay = 1;
	int baud;

	/*
	 * The logic involved in setting the baudrate can be cleanly split in 3 steps.
	 * Obtaining the actual baud rate is a little tricky since unix traditionally
	 * somehow ignored the possibility to set non-standard baud rates.
	 * 1. Standard baud rates are set in tty->termios->c_cflag
	 * 2. If these are not enough, you can set any speed using alt_speed as follows:
	 *    - set tty->termios->c_cflag speed to B38400
	 *    - set your real speed in tty->alt_speed; it gets ignored when
	 *      alt_speed==0, (or)
	 *    - call TIOCSSERIAL ioctl with (struct serial_struct) set as follows:
	 *      flags & ASYNC_SPD_MASK == ASYNC_SPD_[HI, VHI, SHI, WARP], this just
	 *      sets alt_speed to (HI: 57600, VHI: 115200, SHI: 230400, WARP: 460800)
	 * ** Steps 1, 2 are done courtesy of tty_get_baud_rate
	 * 3. You can also set baud rate by setting custom divisor as follows
	 *    - set tty->termios->c_cflag speed to B38400
	 *    - call TIOCSSERIAL ioctl with (struct serial_struct) set as follows:
	 *      o flags & ASYNC_SPD_MASK == ASYNC_SPD_CUST
	 *      o custom_divisor set to baud_base / your_new_baudrate
	 * ** Step 3 is done courtesy of code borrowed from serial.c - I should really
	 *    spend some time and separate+move this common code to serial.c, it is
	 *    replicated in nearly every serial driver you see.
	 */

	/* 1. Get the baud rate from the tty settings, this observes alt_speed hack */

	baud = tty_get_baud_rate(port->tty);
	dbg("%s - tty_get_baud_rate reports speed %d", __FUNCTION__, baud);

	/* 2. Observe async-compatible custom_divisor hack, update baudrate if needed */

	if (baud == 38400 &&
	    ((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST) &&
	     (priv->custom_divisor)) {
		baud = priv->baud_base / priv->custom_divisor;
		dbg("%s - custom divisor %d sets baud rate to %d", __FUNCTION__, priv->custom_divisor, baud);
	}

	/* 3. Convert baudrate to device-specific divisor */

	if (!baud) baud = 9600;
	switch(priv->chip_type) {
	case SIO: /* SIO chip */
		switch(baud) {
		case 300: div_value = ftdi_sio_b300; break;
		case 600: div_value = ftdi_sio_b600; break;
		case 1200: div_value = ftdi_sio_b1200; break;
		case 2400: div_value = ftdi_sio_b2400; break;
		case 4800: div_value = ftdi_sio_b4800; break;
		case 9600: div_value = ftdi_sio_b9600; break;
		case 19200: div_value = ftdi_sio_b19200; break;
		case 38400: div_value = ftdi_sio_b38400; break;
		case 57600: div_value = ftdi_sio_b57600;  break;
		case 115200: div_value = ftdi_sio_b115200; break;
		} /* baud */
		if (div_value == 0) {
			dbg("%s - Baudrate (%d) requested is not supported", __FUNCTION__,  baud);
			div_value = ftdi_sio_b9600;
			baud = 9600;
			div_okay = 0;
		}
		break;
	case FT8U232AM: /* 8U232AM chip */
		if (baud <= 3000000) {
			div_value = ftdi_232am_baud_to_divisor(baud);
		} else {
	                dbg("%s - Baud rate too high!", __FUNCTION__);
			baud = 9600;
			div_value = ftdi_232am_baud_to_divisor(9600);
			div_okay = 0;
		}
		break;
	case FT232BM: /* FT232BM chip */
	case FT2232C: /* FT2232C chip */
	case FT232RL:
		if (baud <= 3000000) {
			div_value = ftdi_232bm_baud_to_divisor(baud);
		} else {
	                dbg("%s - Baud rate too high!", __FUNCTION__);
			div_value = ftdi_232bm_baud_to_divisor(9600);
			div_okay = 0;
			baud = 9600;
		}
		break;
	case FT2232H: /* FT2232H chip */
	case FT4232H: /* FT4232H chip */
		if ((baud <= 12000000) & (baud >= 1200)) {			
			div_value = ftdi_2232h_baud_to_divisor(baud);
		} else if (baud < 1200) {
			div_value = ftdi_232bm_baud_to_divisor(baud);
		} else {
			dbg("%s - Baud rate too high!", __FUNCTION__);
			div_value = ftdi_232bm_baud_to_divisor(9600);
			div_okay = 0;
			baud = 9600;
		}
		break;
	} /* priv->chip_type */

	if (div_okay) {
		dbg("%s - Baud rate set to %d (divisor 0x%lX) on chip %s",
			__FUNCTION__, baud, (unsigned long)div_value,
			ftdi_chip_name[priv->chip_type]);
	}

	tty_encode_baud_rate(port->tty, baud, baud);
	return(div_value);
}


static int get_serial_info(struct usb_serial_port * port, struct serial_struct __user * retinfo)
{
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	struct serial_struct tmp;

	if (!retinfo)
		return -EFAULT;
	memset(&tmp, 0, sizeof(tmp));
	tmp.flags = priv->flags;
	tmp.baud_base = priv->baud_base;
	tmp.custom_divisor = priv->custom_divisor;
	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
		return -EFAULT;
	return 0;
} /* get_serial_info */


static int set_serial_info(struct usb_serial_port * port, struct serial_struct __user * newinfo)
{ /* set_serial_info */
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	struct serial_struct new_serial;
	struct ftdi_private old_priv;

	if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
		return -EFAULT;
	old_priv = * priv;

	/* Do error checking and permission checking */

	if (!capable(CAP_SYS_ADMIN)) {
		if (((new_serial.flags & ~ASYNC_USR_MASK) !=
		     (priv->flags & ~ASYNC_USR_MASK)))
			return -EPERM;
		priv->flags = ((priv->flags & ~ASYNC_USR_MASK) |
			       (new_serial.flags & ASYNC_USR_MASK));
		priv->custom_divisor = new_serial.custom_divisor;
		goto check_and_exit;
	}

	if ((new_serial.baud_base != priv->baud_base) &&
	    (new_serial.baud_base < 9600))
		return -EINVAL;

	/* Make the changes - these are privileged changes! */

	priv->flags = ((priv->flags & ~ASYNC_FLAGS) |
	               (new_serial.flags & ASYNC_FLAGS));
	priv->custom_divisor = new_serial.custom_divisor;

	port->tty->low_latency = (priv->flags & ASYNC_LOW_LATENCY) ? 1 : 0;

check_and_exit:
	if ((old_priv.flags & ASYNC_SPD_MASK) !=
	     (priv->flags & ASYNC_SPD_MASK)) {
		if ((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
			port->tty->alt_speed = 57600;
		else if ((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
			port->tty->alt_speed = 115200;
		else if ((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
			port->tty->alt_speed = 230400;
		else if ((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
			port->tty->alt_speed = 460800;
		else
			port->tty->alt_speed = 0;
	}
	if (((old_priv.flags & ASYNC_SPD_MASK) !=
	     (priv->flags & ASYNC_SPD_MASK)) ||
	    (((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST) &&
	     (old_priv.custom_divisor != priv->custom_divisor))) {
		change_speed(port);
	}

	return (0);

} /* set_serial_info */


/* Determine type of FTDI chip based on USB config and descriptor. */
static void ftdi_determine_type(struct usb_serial_port *port)
{
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	struct usb_serial *serial = port->serial;
	struct usb_device *udev = serial->dev;
	unsigned version;
	unsigned interfaces;

	/* Assume it is not the original SIO device for now. */
	priv->baud_base = 48000000 / 2;
	priv->write_offset = 0;

	version = le16_to_cpu(udev->descriptor.bcdDevice);
	interfaces = udev->actconfig->desc.bNumInterfaces;
	dbg("%s: bcdDevice = 0x%x, bNumInterfaces = %u", __FUNCTION__,
			version, interfaces);
	if (interfaces > 1) {
		int inter;

		/* Multiple interfaces.*/
		if (version == 0x0800) {
			priv->chip_type = FT4232H;
			// Hi-speed - baud clock runs at 120MHz
			priv->baud_base = 120000000 / 2;
		} else if (version == 0x0700) {
			priv->chip_type = FT2232H;
			// Hi-speed - baud clock runs at 120MHz
			priv->baud_base = 120000000 / 2;		
		} else
			priv->chip_type = FT2232C;

		/* Determine interface code. */
		inter = serial->interface->altsetting->desc.bInterfaceNumber;
		if (inter == 0) {
			priv->interface = INTERFACE_A;
		} else  if (inter == 1) {
			priv->interface = INTERFACE_B;
		} else  if (inter == 2) {
			priv->interface = INTERFACE_C;
		} else  if (inter == 3) {
			priv->interface = INTERFACE_D;
		}
		/* BM-type devices have a bug where bcdDevice gets set
		 * to 0x200 when iSerialNumber is 0.  */
		if (version < 0x500) {
			dbg("%s: something fishy - bcdDevice too low for multi-interface device",
					__FUNCTION__);
		}
	} else if (version < 0x200) {
		/* Old device.  Assume its the original SIO. */
		priv->chip_type = SIO;
		priv->baud_base = 12000000 / 16;
		priv->write_offset = 1;
	} else if (version < 0x400) {
		/* Assume its an FT8U232AM (or FT8U245AM) */
		/* (It might be a BM because of the iSerialNumber bug,
		 * but it will still work as an AM device.) */
		priv->chip_type = FT8U232AM;
	} else if (version < 0x600) {
		/* Assume its an FT232BM (or FT245BM) */
		priv->chip_type = FT232BM;
	} else {
		/* Assume its an FT232R  */
		priv->chip_type = FT232RL;
	}
	info("Detected %s", ftdi_chip_name[priv->chip_type]);
}


/*
 * ***************************************************************************
 * Sysfs Attribute
 * ***************************************************************************
 */

static ssize_t show_latency_timer(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct usb_serial_port *port = to_usb_serial_port(dev);
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	struct usb_device *udev = port->serial->dev;
	unsigned short latency = 0;
	int rv = 0;


	dbg("%s",__FUNCTION__);

	rv = usb_control_msg(udev,
			     usb_rcvctrlpipe(udev, 0),
			     FTDI_SIO_GET_LATENCY_TIMER_REQUEST,
			     FTDI_SIO_GET_LATENCY_TIMER_REQUEST_TYPE,
			     0, priv->interface,
			     (char*) &latency, 1, WDR_TIMEOUT);

	if (rv < 0) {
		dev_err(dev, "Unable to read latency timer: %i\n", rv);
		return -EIO;
	}
	return sprintf(buf, "%i\n", latency);
}

/* Write a new value of the latency timer, in units of milliseconds. */
static ssize_t store_latency_timer(struct device *dev, struct device_attribute *attr, const char *valbuf,
				   size_t count)
{
	struct usb_serial_port *port = to_usb_serial_port(dev);
	struct ftdi_private *priv = usb_get_serial_port_data(port);
	struct usb_device *udev = port->serial->dev;
	char buf[1];
	int v = simple_strtoul(valbuf, NULL, 10);
	int rv = 0;

	dbg("%s: setting latency timer = %i", __FUNCTION__, v);

	rv = usb_control_msg(udev,
			     usb_sndctrlpipe(udev, 0),
			     FTDI_SIO_SET_LATENCY_TIMER_REQUEST,
			     FTDI_SIO_SET_LATENCY_TIMER_REQUEST_TYPE,
			     v, priv->interface,
			     buf, 0, WDR_TIMEOUT);