[IRDA]: Initial support for MCS7780 based dongles

The MosChip MCS7780 chipset is an IrDA USB bridge that
doesn't conform with the IrDA-USB standard and thus needs
its separate driver.
Tested on an actual MCS7780 based dongle.

Original implementation by Brian Pugh <bpugh@cs.pdx.edu>
Signed-off-by: NSamuel Ortiz <samuel@sortiz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/irda/Kconfig

@@ -417,5 +417,20 @@ config PXA_FICP
 	  available capabilities may vary from one PXA2xx target to
 	  another.
 
+config MCS_FIR
+	tristate "MosChip MCS7780 IrDA-USB dongle"
+	depends on IRDA && USB && EXPERIMENTAL
+	help
+	  Say Y or M here if you want to build support for the MosChip
+	  MCS7780 IrDA-USB bridge device driver.
+
+	  USB bridge based on the MosChip MCS7780 don't conform to the
+	  IrDA-USB device class specification, and therefore need their
+	  own specific driver. Those dongles support SIR and FIR (4Mbps)
+	  speeds.
+
+	  To compile it as a module, choose M here: the module will be called
+	  mcs7780.
+
 endmenu
 

drivers/net/irda/Makefile

@@ -19,6 +19,7 @@ obj-$(CONFIG_ALI_FIR)		+= ali-ircc.o
 obj-$(CONFIG_VLSI_FIR)		+= vlsi_ir.o
 obj-$(CONFIG_VIA_FIR)		+= via-ircc.o
 obj-$(CONFIG_PXA_FICP)	        += pxaficp_ir.o
+obj-$(CONFIG_MCS_FIR)	        += mcs7780.o
 # Old dongle drivers for old SIR drivers
 obj-$(CONFIG_ESI_DONGLE_OLD)		+= esi.o
 obj-$(CONFIG_TEKRAM_DONGLE_OLD)	+= tekram.o

drivers/net/irda/mcs7780.c

+/*****************************************************************************
+*
+* Filename:      mcs7780.c
+* Version:       0.4-alpha
+* Description:   Irda MosChip USB Dongle Driver
+* Authors:       Lukasz Stelmach <stlman@poczta.fm>
+* 		 Brian Pugh <bpugh@cs.pdx.edu>
+*		 Judy Fischbach <jfisch@cs.pdx.edu>
+*
+*       Based on stir4200 driver, but some things done differently.
+*       Based on earlier driver by Paul Stewart <stewart@parc.com>
+*
+*       Copyright (C) 2000, Roman Weissgaerber <weissg@vienna.at>
+*       Copyright (C) 2001, Dag Brattli <dag@brattli.net>
+*       Copyright (C) 2001, Jean Tourrilhes <jt@hpl.hp.com>
+*       Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
+*       Copyright (C) 2005, Lukasz Stelmach <stlman@poczta.fm>
+*       Copyright (C) 2005, Brian Pugh <bpugh@cs.pdx.edu>
+*       Copyright (C) 2005, Judy Fischbach <jfisch@cs.pdx.edu>
+*
+*       This program is free software; you can redistribute it and/or modify
+*       it under the terms of the GNU General Public License as published by
+*       the Free Software Foundation; either version 2 of the License, or
+*       (at your option) any later version.
+*
+*       This program is distributed in the hope that it will be useful,
+*       but WITHOUT ANY WARRANTY; without even the implied warranty of
+*       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*       GNU General Public License for more details.
+*
+*       You should have received a copy of the GNU General Public License
+*       along with this program; if not, write to the Free Software
+*       Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*
+*****************************************************************************/
+
+/*
+ * MCS7780 is a simple USB to IrDA bridge by MosChip. It is neither
+ * compatibile with irda-usb nor with stir4200. Although it is quite
+ * similar to the later as far as general idea of operation is concerned.
+ * That is it requires the software to do all the framing job at SIR speeds.
+ * The hardware does take care of the framing at MIR and FIR speeds.
+ * It supports all speeds from 2400 through 4Mbps
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/kref.h>
+#include <linux/usb.h>
+#include <linux/device.h>
+#include <linux/crc32.h>
+
+#include <asm/unaligned.h>
+#include <asm/byteorder.h>
+#include <asm/uaccess.h>
+
+#include <net/irda/irda.h>
+#include <net/irda/wrapper.h>
+#include <net/irda/crc.h>
+
+#include "mcs7780.h"
+
+#define MCS_VENDOR_ID 0x9710
+#define MCS_PRODUCT_ID 0x7780
+
+static struct usb_device_id mcs_table[] = {
+	/* MosChip Corp.,  MCS7780 FIR-USB Adapter */
+	{USB_DEVICE(MCS_VENDOR_ID, MCS_PRODUCT_ID)},
+	{},
+};
+
+MODULE_AUTHOR("Brian Pugh <bpugh@cs.pdx.edu>");
+MODULE_DESCRIPTION("IrDA-USB Dongle Driver for MosChip MCS7780");
+MODULE_VERSION("0.3alpha");
+MODULE_LICENSE("GPL");
+
+MODULE_DEVICE_TABLE(usb, mcs_table);
+
+static int qos_mtt_bits = 0x07 /* > 1ms */ ;
+module_param(qos_mtt_bits, int, 0);
+MODULE_PARM_DESC(qos_mtt_bits, "Minimum Turn Time");
+
+static int receive_mode = 0x1;
+module_param(receive_mode, int, 0);
+MODULE_PARM_DESC(receive_mode,
+		 "Receive mode of the device (1:fast, 0:slow, default:1)");
+
+static int sir_tweak = 1;
+module_param(sir_tweak, int, 0444);
+MODULE_PARM_DESC(sir_tweak,
+		 "Default pulse width (1:1.6us, 0:3/16 bit, default:1).");
+
+static int transceiver_type = MCS_TSC_VISHAY;
+module_param(transceiver_type, int, 0444);
+MODULE_PARM_DESC(transceiver_type, "IR transceiver type, see mcs7780.h.");
+
+struct usb_driver mcs_driver = {
+	.name = "mcs7780",
+	.probe = mcs_probe,
+	.disconnect = mcs_disconnect,
+	.id_table = mcs_table,
+};
+
+/* speed flag selection by direct addressing.
+addr = (speed >> 8) & 0x0f
+
+0x1   57600	 0x2  115200	 0x4 1152000	 0x5    9600
+0x6   38400	 0x9    2400	 0xa  576000	 0xb   19200
+
+4Mbps (or 2400) must be checked separately. Since it also has
+to be programmed in a different manner that is not a big problem.
+*/
+static __u16 mcs_speed_set[16] = { 0,
+	MCS_SPEED_57600,
+	MCS_SPEED_115200,
+	0,
+	MCS_SPEED_1152000,
+	MCS_SPEED_9600,
+	MCS_SPEED_38400,
+	0, 0,
+	MCS_SPEED_2400,
+	MCS_SPEED_576000,
+	MCS_SPEED_19200,
+	0, 0, 0,
+};
+
+/* Set given 16 bit register with a 16 bit value. Send control message
+ * to set dongle register. */
+static int mcs_set_reg(struct mcs_cb *mcs, __u16 reg, __u16 val)
+{
+	struct usb_device *dev = mcs->usbdev;
+	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0), MCS_WRREQ,
+			       MCS_WR_RTYPE, val, reg, NULL, 0,
+			       msecs_to_jiffies(MCS_CTRL_TIMEOUT));
+}
+
+/* Get 16 bit register value. Send contol message to read dongle register. */
+static int mcs_get_reg(struct mcs_cb *mcs, __u16 reg, __u16 * val)
+{
+	struct usb_device *dev = mcs->usbdev;
+	int ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), MCS_RDREQ,
+				  MCS_RD_RTYPE, 0, reg, val, 2,
+				  msecs_to_jiffies(MCS_CTRL_TIMEOUT));
+
+	return ret;
+}
+
+/* Setup a communication between mcs7780 and TFDU chips.  It is described
+ * in more detail in the data sheet.  The setup sequence puts the the
+ * vishay tranceiver into high speed mode.  It will also receive SIR speed
+ * packets but at reduced sensitivity.
+ */
+
+/* 0: OK 1:ERROR */
+static inline int mcs_setup_transceiver_vishay(struct mcs_cb *mcs)
+{
+	int ret = 0;
+	__u16 rval;
+
+	/* mcs_get_reg should read exactly two bytes from the dongle */
+	ret = mcs_get_reg(mcs, MCS_XCVR_REG, &rval);
+	if (unlikely(ret != 2)) {
+		ret = -EIO;
+		goto error;
+	}
+
+	/* The MCS_XCVR_CONF bit puts the transceiver into configuration
+	 * mode.  The MCS_MODE0 bit must start out high (1) and then
+	 * transition to low and the MCS_STFIR and MCS_MODE1 bits must
+	 * be low.
+	 */
+	rval |= (MCS_MODE0 | MCS_XCVR_CONF);
+	rval &= ~MCS_STFIR;
+	rval &= ~MCS_MODE1;
+	ret = mcs_set_reg(mcs, MCS_XCVR_REG, rval);
+	if (unlikely(ret))
+		goto error;
+
+	rval &= ~MCS_MODE0;
+	ret = mcs_set_reg(mcs, MCS_XCVR_REG, rval);
+	if (unlikely(ret))
+		goto error;
+
+	rval &= ~MCS_XCVR_CONF;
+	ret = mcs_set_reg(mcs, MCS_XCVR_REG, rval);
+	if (unlikely(ret))
+		goto error;
+
+	ret = 0;
+	error:
+		return ret;
+}
+
+/* Setup a communication between mcs7780 and agilent chip. */
+static inline int mcs_setup_transceiver_agilent(struct mcs_cb *mcs)
+{
+	IRDA_WARNING("This transceiver type is not supported yet.");
+	return 1;
+}
+
+/* Setup a communication between mcs7780 and sharp chip. */
+static inline int mcs_setup_transceiver_sharp(struct mcs_cb *mcs)
+{
+	IRDA_WARNING("This transceiver type is not supported yet.");
+	return 1;
+}
+
+/* Common setup for all transceivers */
+static inline int mcs_setup_transceiver(struct mcs_cb *mcs)
+{
+	int ret = 0;
+	__u16 rval;
+	char *msg;
+
+	msg = "Basic transceiver setup error.";
+
+	/* read value of MODE Register, set the DRIVER and RESET bits
+	* and write value back out to MODE Register
+	*/
+	ret = mcs_get_reg(mcs, MCS_MODE_REG, &rval);
+	if(unlikely(ret != 2))
+		goto error;
+	rval |= MCS_DRIVER;	/* put the mcs7780 into configuration mode. */
+	ret = mcs_set_reg(mcs, MCS_MODE_REG, rval);
+	if(unlikely(ret))
+		goto error;
+
+	rval = 0;		/* set min pulse width to 0 initially. */
+	ret = mcs_set_reg(mcs, MCS_MINRXPW_REG, rval);
+	if(unlikely(ret))
+		goto error;
+
+	ret = mcs_get_reg(mcs, MCS_MODE_REG, &rval);
+	if(unlikely(ret != 2))
+		goto error;
+
+	rval &= ~MCS_FIR;	/* turn off fir mode. */
+	if(mcs->sir_tweak)
+		rval |= MCS_SIR16US;	/* 1.6us pulse width */
+	else
+		rval &= ~MCS_SIR16US;	/* 3/16 bit time pulse width */
+
+	/* make sure ask mode and back to back packets are off. */
+	rval &= ~(MCS_BBTG | MCS_ASK);
+
+	rval &= ~MCS_SPEED_MASK;
+	rval |= MCS_SPEED_9600;		/* make sure initial speed is 9600. */
+	mcs->speed = 9600;
+	mcs->new_speed = 0;		/* new_speed is set to 0 */
+	rval &= ~MCS_PLLPWDN;		/* disable power down. */
+
+	/* make sure device determines direction and that the auto send sip
+	 * pulse are on.
+	 */
+	rval |= MCS_DTD | MCS_SIPEN;
+
+	ret = mcs_set_reg(mcs, MCS_MODE_REG, rval);
+	if(unlikely(ret))
+		goto error;
+
+	msg = "transceiver model specific setup error.";
+	switch (mcs->transceiver_type) {
+	case MCS_TSC_VISHAY:
+		ret = mcs_setup_transceiver_vishay(mcs);
+		break;
+
+	case MCS_TSC_SHARP:
+		ret = mcs_setup_transceiver_sharp(mcs);
+		break;
+
+	case MCS_TSC_AGILENT:
+		ret = mcs_setup_transceiver_agilent(mcs);
+		break;
+
+	default:
+		IRDA_WARNING("Unknown transceiver type: %d",
+			     mcs->transceiver_type);
+		ret = 1;
+	}
+	if (unlikely(ret))
+		goto error;
+
+	/* If transceiver is not SHARP, then if receive mode set
+	* on the RXFAST bit in the XCVR Register otherwise unset it
+	*/
+	if (mcs->transceiver_type != MCS_TSC_SHARP) {
+
+		ret = mcs_get_reg(mcs, MCS_XCVR_REG, &rval);
+		if (unlikely(ret != 2))
+			goto error;
+		if (mcs->receive_mode)
+			rval |= MCS_RXFAST;
+		else
+			rval &= ~MCS_RXFAST;
+		ret = mcs_set_reg(mcs, MCS_XCVR_REG, rval);
+		if (unlikely(ret))
+			goto error;
+	}
+
+	msg = "transceiver reset.";
+
+	ret = mcs_get_reg(mcs, MCS_MODE_REG, &rval);
+	if (unlikely(ret != 2))
+		goto error;
+
+	/* reset the mcs7780 so all changes take effect. */
+	rval &= ~MCS_RESET;
+	ret = mcs_set_reg(mcs, MCS_MODE_REG, rval);
+	if (unlikely(ret))
+		goto error;
+	else
+		return ret;
+
+error:
+	IRDA_ERROR("%s", msg);
+	return ret;
+}
+
+/* Wraps the data in format for SIR */
+static inline int mcs_wrap_sir_skb(struct sk_buff *skb, __u8 * buf)
+{
+	int wraplen;
+
+	/* 2: full frame length, including "the length" */
+	wraplen = async_wrap_skb(skb, buf + 2, 4094);
+
+	wraplen += 2;
+	buf[0] = wraplen & 0xff;
+	buf[1] = (wraplen >> 8) & 0xff;
+
+	return wraplen;
+}
+
+/* Wraps the data in format for FIR */
+static unsigned mcs_wrap_fir_skb(const struct sk_buff *skb, __u8 *buf)
+{
+	unsigned int len = 0;
+	__u32 fcs = ~(crc32_le(~0, skb->data, skb->len));
+
+	/* add 2 bytes for length value and 4 bytes for fcs. */
+	len = skb->len + 6;
+
+	/* The mcs7780 requires that the first two bytes are the packet
+	 * length in little endian order.  Note: the length value includes
+	 * the two bytes for the length value itself.
+	 */
+	buf[0] = len & 0xff;
+	buf[1] = (len >> 8) & 0xff;
+	/* copy the data into the tx buffer. */
+	memcpy(buf+2, skb->data, skb->len);
+	/* put the fcs in the last four bytes in little endian order. */
+	buf[len - 4] = fcs & 0xff;
+	buf[len - 3] = (fcs >> 8) & 0xff;
+	buf[len - 2] = (fcs >> 16) & 0xff;
+	buf[len - 1] = (fcs >> 24) & 0xff;
+
+	return len;
+}
+
+/* Wraps the data in format for MIR */
+static unsigned mcs_wrap_mir_skb(const struct sk_buff *skb, __u8 *buf)
+{
+	__u16 fcs = 0;
+	int len = skb->len + 4;
+
+	fcs = ~(irda_calc_crc16(~fcs, skb->data, skb->len));
+	/* put the total packet length in first.  Note: packet length
+	 * value includes the two bytes that hold the packet length
+	 * itself.
+	 */
+	buf[0] = len & 0xff;
+	buf[1] = (len >> 8) & 0xff;
+	/* copy the data */
+	memcpy(buf+2, skb->data, skb->len);
+	/* put the fcs in last two bytes in little endian order. */
+	buf[len - 2] = fcs & 0xff;
+	buf[len - 1] = (fcs >> 8) & 0xff;
+
+	return len;
+}
+
+/* Unwrap received packets at MIR speed.  A 16 bit crc_ccitt checksum is
+ * used for the fcs.  When performed over the entire packet the result
+ * should be GOOD_FCS = 0xf0b8.  Hands the unwrapped data off to the IrDA
+ * layer via a sk_buff.
+ */
+static void mcs_unwrap_mir(struct mcs_cb *mcs, __u8 *buf, int len)
+{
+	__u16 fcs;
+	int new_len;
+	struct sk_buff *skb;
+
+	/* Assume that the frames are going to fill a single packet
+	 * rather than span multiple packets.
+	 */
+
+	new_len = len - 2;
+	if(unlikely(new_len <= 0)) {
+		IRDA_ERROR("%s short frame length %d\n",
+			     mcs->netdev->name, new_len);
+		++mcs->stats.rx_errors;
+		++mcs->stats.rx_length_errors;
+		return;
+	}
+	fcs = 0;
+	fcs = irda_calc_crc16(~fcs, buf, len);
+
+	if(fcs != GOOD_FCS) {
+		IRDA_ERROR("crc error calc 0x%x len %d\n",
+			   fcs, new_len);
+		mcs->stats.rx_errors++;
+		mcs->stats.rx_crc_errors++;
+		return;
+	}
+
+	skb = dev_alloc_skb(new_len + 1);
+	if(unlikely(!skb)) {
+		++mcs->stats.rx_dropped;
+		return;
+	}
+
+	skb_reserve(skb, 1);
+	memcpy(skb->data, buf, new_len);
+	skb_put(skb, new_len);
+	skb->mac.raw = skb->data;
+	skb->protocol = htons(ETH_P_IRDA);
+	skb->dev = mcs->netdev;
+
+	netif_rx(skb);
+
+	mcs->stats.rx_packets++;
+	mcs->stats.rx_bytes += new_len;
+
+	return;
+}
+
+/* Unwrap received packets at FIR speed.  A 32 bit crc_ccitt checksum is
+ * used for the fcs.  Hands the unwrapped data off to the IrDA
+ * layer via a sk_buff.
+ */
+static void mcs_unwrap_fir(struct mcs_cb *mcs, __u8 *buf, int len)
+{
+	__u32 fcs;
+	int new_len;
+	struct sk_buff *skb;
+
+	/* Assume that the frames are going to fill a single packet
+	 * rather than span multiple packets.  This is most likely a false
+	 * assumption.
+	 */
+
+	new_len = len - 4;
+	if(unlikely(new_len <= 0)) {
+		IRDA_ERROR("%s short frame length %d\n",
+			   mcs->netdev->name, new_len);
+		++mcs->stats.rx_errors;
+		++mcs->stats.rx_length_errors;
+		return;
+	}
+
+	fcs = ~(crc32_le(~0, buf, new_len));
+	if(fcs != le32_to_cpu(get_unaligned((u32 *)(buf+new_len)))) {
+		IRDA_ERROR("crc error calc 0x%x len %d\n", fcs, new_len);
+		mcs->stats.rx_errors++;
+		mcs->stats.rx_crc_errors++;
+		return;
+	}
+
+	skb = dev_alloc_skb(new_len + 1);
+	if(unlikely(!skb)) {
+		++mcs->stats.rx_dropped;
+		return;
+	}
+
+	skb_reserve(skb, 1);
+	memcpy(skb->data, buf, new_len);
+	skb_put(skb, new_len);
+	skb->mac.raw = skb->data;
+	skb->protocol = htons(ETH_P_IRDA);
+	skb->dev = mcs->netdev;
+
+	netif_rx(skb);
+
+	mcs->stats.rx_packets++;
+	mcs->stats.rx_bytes += new_len;
+
+	return;
+}
+
+
+/* Allocates urbs for both receive and transmit.
+ * If alloc fails return error code 0 (fail) otherwise
+ * return error code 1 (success).
+ */
+static inline int mcs_setup_urbs(struct mcs_cb *mcs)
+{
+	mcs->rx_urb = NULL;
+
+	mcs->tx_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!mcs->tx_urb)
+		return 0;
+
+	mcs->rx_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!mcs->rx_urb)
+		return 0;
+
+	return 1;
+}
+
+/* Sets up state to be initially outside frame, gets receive urb,
+ * sets status to successful and then submits the urb to start
+ * receiving the data.
+ */
+static inline int mcs_receive_start(struct mcs_cb *mcs)
+{
+	mcs->rx_buff.in_frame = FALSE;
+	mcs->rx_buff.state = OUTSIDE_FRAME;
+
+	usb_fill_bulk_urb(mcs->rx_urb, mcs->usbdev,
+			  usb_rcvbulkpipe(mcs->usbdev, mcs->ep_in),
+			  mcs->in_buf, 4096, mcs_receive_irq, mcs);
+
+	mcs->rx_urb->status = 0;
+	return usb_submit_urb(mcs->rx_urb, GFP_KERNEL);
+}
+
+/* Finds the in and out endpoints for the mcs control block */
+static inline int mcs_find_endpoints(struct mcs_cb *mcs,
+				     struct usb_host_endpoint *ep, int epnum)
+{
+	int i;
+	int ret = 0;
+
+	/* If no place to store the endpoints just return */
+	if (!ep)
+		return ret;
+
+	/* cycle through all endpoints, find the first two that are DIR_IN */
+	for (i = 0; i < epnum; i++) {
+		if (ep[i].desc.bEndpointAddress & USB_DIR_IN)
+			mcs->ep_in = ep[i].desc.bEndpointAddress;
+		else
+			mcs->ep_out = ep[i].desc.bEndpointAddress;
+
+		/* MosChip says that the chip has only two bulk
+		 * endpoints. Find one for each direction and move on.
+		 */
+		if ((mcs->ep_in != 0) && (mcs->ep_out != 0)) {
+			ret = 1;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static void mcs_speed_work(void *arg)
+{
+	struct mcs_cb *mcs = arg;
+	struct net_device *netdev = mcs->netdev;
+
+	mcs_speed_change(mcs);
+	netif_wake_queue(netdev);
+}
+
+/* Function to change the speed of the mcs7780.  Fully supports SIR,
+ * MIR, and FIR speeds.
+ */
+static int mcs_speed_change(struct mcs_cb *mcs)
+{
+	int ret = 0;
+	int rst = 0;
+	int cnt = 0;
+	__u16 nspeed;
+	__u16 rval;
+
+	nspeed = mcs_speed_set[(mcs->new_speed >> 8) & 0x0f];
+
+	do {
+		mcs_get_reg(mcs, MCS_RESV_REG, &rval);
+	} while(cnt++ < 100 && (rval & MCS_IRINTX));
+
+	if(cnt >= 100) {
+		IRDA_ERROR("unable to change speed");
+		ret = -EIO;
+		goto error;
+	}
+
+	mcs_get_reg(mcs, MCS_MODE_REG, &rval);
+
+	/* MINRXPW values recomended by MosChip */
+	if (mcs->new_speed <= 115200) {
+		rval &= ~MCS_FIR;
+
+		if ((rst = (mcs->speed > 115200)))
+			mcs_set_reg(mcs, MCS_MINRXPW_REG, 0);
+
+	} else if (mcs->new_speed <= 1152000) {
+		rval &= ~MCS_FIR;
+
+		if ((rst = !(mcs->speed == 576000 || mcs->speed == 1152000)))
+			mcs_set_reg(mcs, MCS_MINRXPW_REG, 5);
+
+	} else {
+		rval |= MCS_FIR;
+
+		if ((rst = (mcs->speed != 4000000)))
+			mcs_set_reg(mcs, MCS_MINRXPW_REG, 5);
+
+	}
+
+	rval &= ~MCS_SPEED_MASK;
+	rval |= nspeed;
+
+	ret = mcs_set_reg(mcs, MCS_MODE_REG, rval);
+	if (unlikely(ret))
+		goto error;
+
+	if (rst)
+		switch (mcs->transceiver_type) {
+		case MCS_TSC_VISHAY:
+			ret = mcs_setup_transceiver_vishay(mcs);
+			break;
+
+		case MCS_TSC_SHARP:
+			ret = mcs_setup_transceiver_sharp(mcs);
+			break;
+
+		case MCS_TSC_AGILENT:
+			ret = mcs_setup_transceiver_agilent(mcs);
+			break;
+
+		default:
+			ret = 1;
+			IRDA_WARNING("Unknown transceiver type: %d",
+				     mcs->transceiver_type);
+		}
+	if (unlikely(ret))
+		goto error;
+
+	mcs_get_reg(mcs, MCS_MODE_REG, &rval);
+	rval &= ~MCS_RESET;
+	ret = mcs_set_reg(mcs, MCS_MODE_REG, rval);
+
+	mcs->speed = mcs->new_speed;
+	error:
+		mcs->new_speed = 0;
+		return ret;
+}
+
+/* Ioctl calls not supported at this time.  Can be an area of future work. */
+static int mcs_net_ioctl(struct net_device *netdev, struct ifreq *rq, int cmd)
+{
+	/* struct if_irda_req *irq = (struct if_irda_req *)rq; */
+	/* struct mcs_cb *mcs = netdev_priv(netdev); */
+	int ret = 0;
+
+	switch (cmd) {
+	default:
+		ret = -EOPNOTSUPP;
+	}
+
+	return ret;
+}
+
+/* Network device is taken down, done by "ifconfig irda0 down" */
+static int mcs_net_close(struct net_device *netdev)
+{
+	int ret = 0;
+	struct mcs_cb *mcs = netdev_priv(netdev);
+
+	/* Stop transmit processing */
+	netif_stop_queue(netdev);
+
+	/* kill and free the receive and transmit URBs */
+	usb_kill_urb(mcs->rx_urb);
+	usb_free_urb(mcs->rx_urb);
+	usb_kill_urb(mcs->tx_urb);
+	usb_free_urb(mcs->tx_urb);
+
+	/* Stop and remove instance of IrLAP */
+	if (mcs->irlap)
+		irlap_close(mcs->irlap);
+
+	mcs->irlap = NULL;
+	return ret;
+}
+
+/* Network device is taken up, done by "ifconfig irda0 up" */
+static int mcs_net_open(struct net_device *netdev)
+{
+	struct mcs_cb *mcs = netdev_priv(netdev);
+	char hwname[16];
+	int ret = 0;
+
+	ret = usb_clear_halt(mcs->usbdev,
+			     usb_sndbulkpipe(mcs->usbdev, mcs->ep_in));
+	if (ret)
+		goto error1;
+	ret = usb_clear_halt(mcs->usbdev,
+			     usb_rcvbulkpipe(mcs->usbdev, mcs->ep_out));
+	if (ret)
+		goto error1;
+
+	ret = mcs_setup_transceiver(mcs);
+	if (ret)
+		goto error1;
+
+	ret = -ENOMEM;
+
+	/* Initialize for SIR/FIR to copy data directly into skb.  */
+	mcs->receiving = 0;
+	mcs->rx_buff.truesize = IRDA_SKB_MAX_MTU;
+	mcs->rx_buff.skb = dev_alloc_skb(IRDA_SKB_MAX_MTU);
+	if (!mcs->rx_buff.skb)
+		goto error1;
+
+	skb_reserve(mcs->rx_buff.skb, 1);
+	mcs->rx_buff.head = mcs->rx_buff.skb->data;
+	do_gettimeofday(&mcs->rx_time);
+
+	/*
+	 * Now that everything should be initialized properly,
+	 * Open new IrLAP layer instance to take care of us...
+	 * Note : will send immediately a speed change...
+	 */
+	sprintf(hwname, "usb#%d", mcs->usbdev->devnum);
+	mcs->irlap = irlap_open(netdev, &mcs->qos, hwname);
+	if (!mcs->irlap) {
+		IRDA_ERROR("mcs7780: irlap_open failed");
+		goto error2;
+	}
+
+	if (!mcs_setup_urbs(mcs))
+	goto error3;
+
+	ret = mcs_receive_start(mcs);
+	if (ret)
+		goto error3;
+
+	netif_start_queue(netdev);
+	return 0;
+
+	error3:
+		irlap_close(mcs->irlap);
+	error2:
+		kfree_skb(mcs->rx_buff.skb);
+	error1:
+		return ret;
+}
+
+
+/* Get device stats for /proc/net/dev and ifconfig */
+static struct net_device_stats *mcs_net_get_stats(struct net_device *netdev)
+{
+	struct mcs_cb *mcs = netdev_priv(netdev);
+	return &mcs->stats;
+}
+
+/* Receive callback function.  */
+static void mcs_receive_irq(struct urb *urb, struct pt_regs *regs)
+{
+	__u8 *bytes;
+	struct mcs_cb *mcs = urb->context;
+	int i;
+	int ret;
+
+	if (!netif_running(mcs->netdev))
+		return;
+
+	if (urb->status)
+		return;
+
+	if (urb->actual_length > 0) {
+		bytes = urb->transfer_buffer;
+
+		/* MCS returns frames without BOF and EOF
+		 * I assume it returns whole frames.
+		 */
+		/* SIR speed */
+		if(mcs->speed < 576000) {
+			async_unwrap_char(mcs->netdev, &mcs->stats,
+				  &mcs->rx_buff, 0xc0);
+
+			for (i = 0; i < urb->actual_length; i++)
+				async_unwrap_char(mcs->netdev, &mcs->stats,
+					  &mcs->rx_buff, bytes[i]);
+
+			async_unwrap_char(mcs->netdev, &mcs->stats,
+				  &mcs->rx_buff, 0xc1);
+		}
+		/* MIR speed */
+		else if(mcs->speed == 576000 || mcs->speed == 1152000) {
+			mcs_unwrap_mir(mcs, urb->transfer_buffer,
+				urb->actual_length);
+		}
+		/* FIR speed */
+		else {
+			mcs_unwrap_fir(mcs, urb->transfer_buffer,
+				urb->actual_length);
+		}
+		mcs->netdev->last_rx = jiffies;
+		do_gettimeofday(&mcs->rx_time);
+	}
+
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+}
+
+/* Transmit callback funtion.  */
+static void mcs_send_irq(struct urb *urb, struct pt_regs *regs)
+{
+	struct mcs_cb *mcs = urb->context;
+	struct net_device *ndev = mcs->netdev;
+
+	if (unlikely(mcs->new_speed))
+		schedule_work(&mcs->work);
+	else
+		netif_wake_queue(ndev);
+}
+
+/* Transmit callback funtion.  */
+static int mcs_hard_xmit(struct sk_buff *skb, struct net_device *ndev)
+{
+	unsigned long flags;
+	struct mcs_cb *mcs;
+	int wraplen;
+	int ret = 0;
+
+
+	if (skb == NULL || ndev == NULL)
+		return -EINVAL;
+
+	netif_stop_queue(ndev);
+	mcs = netdev_priv(ndev);
+
+	spin_lock_irqsave(&mcs->lock, flags);
+
+	mcs->new_speed = irda_get_next_speed(skb);
+	if (likely(mcs->new_speed == mcs->speed))
+		mcs->new_speed = 0;
+
+	/* SIR speed */
+	if(mcs->speed < 576000) {
+		wraplen = mcs_wrap_sir_skb(skb, mcs->out_buf);
+	}
+	/* MIR speed */
+	else if(mcs->speed == 576000 || mcs->speed == 1152000) {
+		wraplen = mcs_wrap_mir_skb(skb, mcs->out_buf);
+	}
+	/* FIR speed */
+	else {
+		wraplen = mcs_wrap_fir_skb(skb, mcs->out_buf);
+	}
+	usb_fill_bulk_urb(mcs->tx_urb, mcs->usbdev,
+			  usb_sndbulkpipe(mcs->usbdev, mcs->ep_out),
+			  mcs->out_buf, wraplen, mcs_send_irq, mcs);
+
+	if ((ret = usb_submit_urb(mcs->tx_urb, GFP_ATOMIC))) {
+		IRDA_ERROR("failed tx_urb: %d", ret);
+		switch (ret) {
+		case -ENODEV:
+		case -EPIPE:
+			break;
+		default:
+			mcs->stats.tx_errors++;
+			netif_start_queue(ndev);
+		}
+	} else {
+		mcs->stats.tx_packets++;
+		mcs->stats.tx_bytes += skb->len;
+	}
+
+	dev_kfree_skb(skb);
+	spin_unlock_irqrestore(&mcs->lock, flags);
+	return ret;
+}
+
+/*
+ * This function is called by the USB subsystem for each new device in the
+ * system.  Need to verify the device and if it is, then start handling it.
+ */
+static int mcs_probe(struct usb_interface *intf,
+		     const struct usb_device_id *id)
+{
+	struct usb_device *udev = interface_to_usbdev(intf);
+	struct net_device *ndev = NULL;
+	struct mcs_cb *mcs;
+	int ret = -ENOMEM;
+
+	ndev = alloc_irdadev(sizeof(*mcs));
+	if (!ndev)
+		goto error1;
+
+	IRDA_DEBUG(1, "MCS7780 USB-IrDA bridge found at %d.", udev->devnum);
+
+	/* what is it realy for? */
+	SET_MODULE_OWNER(ndev);
+	SET_NETDEV_DEV(ndev, &intf->dev);
+
+	ret = usb_reset_configuration(udev);
+	if (ret != 0) {
+		IRDA_ERROR("mcs7780: usb reset configuration failed");
+		goto error2;
+	}
+
+	mcs = netdev_priv(ndev);
+	mcs->usbdev = udev;
+	mcs->netdev = ndev;
+	spin_lock_init(&mcs->lock);
+
+	/* Initialize QoS for this device */
+	irda_init_max_qos_capabilies(&mcs->qos);
+
+	/* That's the Rx capability. */
+	mcs->qos.baud_rate.bits &=
+	    IR_2400 | IR_9600 | IR_19200 | IR_38400 | IR_57600 | IR_115200
+		| IR_576000 | IR_1152000 | (IR_4000000 << 8);
+
+
+	mcs->qos.min_turn_time.bits &= qos_mtt_bits;
+	irda_qos_bits_to_value(&mcs->qos);
+
+	/* Speed change work initialisation*/
+	INIT_WORK(&mcs->work, mcs_speed_work, mcs);
+
+	/* Override the network functions we need to use */
+	ndev->hard_start_xmit = mcs_hard_xmit;
+	ndev->open = mcs_net_open;
+	ndev->stop = mcs_net_close;
+	ndev->get_stats = mcs_net_get_stats;
+	ndev->do_ioctl = mcs_net_ioctl;
+
+	if (!intf->cur_altsetting)
+		goto error2;
+
+	ret = mcs_find_endpoints(mcs, intf->cur_altsetting->endpoint,
+				 intf->cur_altsetting->desc.bNumEndpoints);
+	if (!ret) {
+		ret = -ENODEV;
+		goto error2;
+	}
+
+	ret = register_netdev(ndev);
+	if (ret != 0)
+		goto error2;
+
+	IRDA_DEBUG(1, "IrDA: Registered MosChip MCS7780 device as %s",
+		   ndev->name);
+
+	mcs->transceiver_type = transceiver_type;
+	mcs->sir_tweak = sir_tweak;
+	mcs->receive_mode = receive_mode;
+
+	usb_set_intfdata(intf, mcs);
+	return 0;
+
+	error2:
+		free_netdev(ndev);
+
+	error1:
+		return ret;
+}
+
+/* The current device is removed, the USB layer tells us to shut down. */
+static void mcs_disconnect(struct usb_interface *intf)
+{
+	struct mcs_cb *mcs = usb_get_intfdata(intf);
+
+	if (!mcs)
+		return;
+
+	flush_scheduled_work();
+
+	unregister_netdev(mcs->netdev);
+	free_netdev(mcs->netdev);
+
+	usb_set_intfdata(intf, NULL);
+	IRDA_DEBUG(0, "MCS7780 now disconnected.");
+}
+
+/* Module insertion */
+static int __init mcs_init(void)
+{
+	int result;
+
+	/* register this driver with the USB subsystem */
+	result = usb_register(&mcs_driver);
+	if (result)
+		IRDA_ERROR("usb_register failed. Error number %d", result);
+
+	return result;
+}
+module_init(mcs_init);
+
+/* Module removal */
+static void __exit mcs_exit(void)
+{
+	/* deregister this driver with the USB subsystem */
+	usb_deregister(&mcs_driver);
+}
+module_exit(mcs_exit);
+

drivers/net/irda/mcs7780.h

+/*****************************************************************************
+*
+* Filename:      mcs7780.h
+* Version:       0.2-alpha
+* Description:   Irda MosChip USB Dongle
+* Status:        Experimental
+* Authors:       Lukasz Stelmach <stlman@poczta.fm>
+*		 Brian Pugh <bpugh@cs.pdx.edu>
+*
+*       Copyright (C) 2005, Lukasz Stelmach <stlman@poczta.fm>
+*       Copyright (C) 2005, Brian Pugh <bpugh@cs.pdx.edu>
+*
+*       This program is free software; you can redistribute it and/or modify
+*       it under the terms of the GNU General Public License as published by
+*       the Free Software Foundation; either version 2 of the License, or
+*       (at your option) any later version.
+*
+*       This program is distributed in the hope that it will be useful,
+*       but WITHOUT ANY WARRANTY; without even the implied warranty of
+*       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*       GNU General Public License for more details.
+*
+*       You should have received a copy of the GNU General Public License
+*       along with this program; if not, write to the Free Software
+*       Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*
+*****************************************************************************/
+#ifndef _MCS7780_H
+#define _MCS7780_H
+
+#define MCS_MODE_SIR		0
+#define MCS_MODE_MIR		1
+#define MCS_MODE_FIR		2
+
+#define MCS_CTRL_TIMEOUT	500
+#define MCS_XMIT_TIMEOUT	500
+/* Possible transceiver types */
+#define MCS_TSC_VISHAY		0	/* Vishay TFD, default choice */
+#define MCS_TSC_AGILENT		1	/* Agilent 3602/3600 */
+#define MCS_TSC_SHARP		2	/* Sharp GP2W1000YP */
+
+/* Requests */
+#define MCS_RD_RTYPE 0xC0
+#define MCS_WR_RTYPE 0x40
+#define MCS_RDREQ    0x0F
+#define MCS_WRREQ    0x0E
+
+/* Register 0x00 */
+#define MCS_MODE_REG	0
+#define MCS_FIR		((__u16)0x0001)
+#define MCS_SIR16US	((__u16)0x0002)
+#define MCS_BBTG	((__u16)0x0004)
+#define MCS_ASK		((__u16)0x0008)
+#define MCS_PARITY	((__u16)0x0010)
+
+/* SIR/MIR speed constants */
+#define MCS_SPEED_SHIFT	    5
+#define MCS_SPEED_MASK	    ((__u16)0x00E0)
+#define MCS_SPEED(x)	    ((x & MCS_SPEED_MASK) >> MCS_SPEED_SHIFT)
+#define MCS_SPEED_2400	    ((0 << MCS_SPEED_SHIFT) & MCS_SPEED_MASK)
+#define MCS_SPEED_9600	    ((1 << MCS_SPEED_SHIFT) & MCS_SPEED_MASK)
+#define MCS_SPEED_19200	    ((2 << MCS_SPEED_SHIFT) & MCS_SPEED_MASK)
+#define MCS_SPEED_38400	    ((3 << MCS_SPEED_SHIFT) & MCS_SPEED_MASK)
+#define MCS_SPEED_57600	    ((4 << MCS_SPEED_SHIFT) & MCS_SPEED_MASK)
+#define MCS_SPEED_115200    ((5 << MCS_SPEED_SHIFT) & MCS_SPEED_MASK)
+#define MCS_SPEED_576000    ((6 << MCS_SPEED_SHIFT) & MCS_SPEED_MASK)
+#define MCS_SPEED_1152000   ((7 << MCS_SPEED_SHIFT) & MCS_SPEED_MASK)
+
+#define MCS_PLLPWDN	((__u16)0x0100)
+#define MCS_DRIVER	((__u16)0x0200)
+#define MCS_DTD		((__u16)0x0400)
+#define MCS_DIR		((__u16)0x0800)
+#define MCS_SIPEN	((__u16)0x1000)
+#define MCS_SENDSIP	((__u16)0x2000)
+#define MCS_CHGDIR	((__u16)0x4000)
+#define MCS_RESET	((__u16)0x8000)
+
+/* Register 0x02 */
+#define MCS_XCVR_REG	2
+#define MCS_MODE0	((__u16)0x0001)
+#define MCS_STFIR	((__u16)0x0002)
+#define MCS_XCVR_CONF	((__u16)0x0004)
+#define MCS_RXFAST	((__u16)0x0008)
+/* TXCUR [6:4] */
+#define MCS_TXCUR_SHIFT	4
+#define MCS_TXCUR_MASK	((__u16)0x0070)
+#define MCS_TXCUR(x)	((x & MCS_TXCUR_MASK) >> MCS_TXCUR_SHIFT)
+#define MCS_SETTXCUR(x,y) \
+	((x & ~MCS_TXCUR_MASK) | (y << MCS_TXCUR_SHIFT) & MCS_TXCUR_MASK)
+
+#define MCS_MODE1	((__u16)0x0080)
+#define MCS_SMODE0	((__u16)0x0100)
+#define MCS_SMODE1	((__u16)0x0200)
+#define MCS_INVTX	((__u16)0x0400)
+#define MCS_INVRX	((__u16)0x0800)
+
+#define MCS_MINRXPW_REG	4
+
+#define MCS_RESV_REG 7
+#define MCS_IRINTX	((__u16)0x0001)
+#define MCS_IRINRX	((__u16)0x0002)
+
+struct mcs_cb {
+	struct usb_device *usbdev;	/* init: probe_irda */
+	struct net_device *netdev;	/* network layer */
+	struct irlap_cb *irlap;	/* The link layer we are binded to */
+	struct net_device_stats stats;	/* network statistics */
+	struct qos_info qos;
+	unsigned int speed;	/* Current speed */
+	unsigned int new_speed;	/* new speed */
+
+	struct work_struct work; /* Change speed work */
+
+	struct sk_buff *tx_pending;
+	char in_buf[4096];	/* transmit/receive buffer */
+	char out_buf[4096];	/* transmit/receive buffer */
+	__u8 *fifo_status;
+
+	iobuff_t rx_buff;	/* receive unwrap state machine */
+	struct timeval rx_time;
+	spinlock_t lock;
+	int receiving;
+
+	__u8 ep_in;
+	__u8 ep_out;
+
+	struct urb *rx_urb;
+	struct urb *tx_urb;
+
+	int transceiver_type;
+	int sir_tweak;
+	int receive_mode;
+};
+
+static int mcs_set_reg(struct mcs_cb *mcs, __u16 reg, __u16 val);
+static int mcs_get_reg(struct mcs_cb *mcs, __u16 reg, __u16 * val);
+
+static inline int mcs_setup_transceiver_vishay(struct mcs_cb *mcs);
+static inline int mcs_setup_transceiver_agilent(struct mcs_cb *mcs);
+static inline int mcs_setup_transceiver_sharp(struct mcs_cb *mcs);
+static inline int mcs_setup_transceiver(struct mcs_cb *mcs);
+static inline int mcs_wrap_sir_skb(struct sk_buff *skb, __u8 * buf);
+static unsigned mcs_wrap_fir_skb(const struct sk_buff *skb, __u8 *buf);
+static unsigned mcs_wrap_mir_skb(const struct sk_buff *skb, __u8 *buf);
+static void mcs_unwrap_mir(struct mcs_cb *mcs, __u8 *buf, int len);
+static void mcs_unwrap_fir(struct mcs_cb *mcs, __u8 *buf, int len);
+static inline int mcs_setup_urbs(struct mcs_cb *mcs);
+static inline int mcs_receive_start(struct mcs_cb *mcs);
+static inline int mcs_find_endpoints(struct mcs_cb *mcs,
+				     struct usb_host_endpoint *ep, int epnum);
+
+static int mcs_speed_change(struct mcs_cb *mcs);
+
+static int mcs_net_ioctl(struct net_device *netdev, struct ifreq *rq, int cmd);
+static int mcs_net_close(struct net_device *netdev);
+static int mcs_net_open(struct net_device *netdev);
+static struct net_device_stats *mcs_net_get_stats(struct net_device *netdev);
+
+static void mcs_receive_irq(struct urb *urb, struct pt_regs *regs);
+static void mcs_send_irq(struct urb *urb, struct pt_regs *regs);
+static int mcs_hard_xmit(struct sk_buff *skb, struct net_device *netdev);
+
+static int mcs_probe(struct usb_interface *intf,
+		     const struct usb_device_id *id);
+static void mcs_disconnect(struct usb_interface *intf);
+
+#endif				/* _MCS7780_H */