diff -N /sys/src/cmd/nusb/serial/cdc.c nusb/serial/cdc.c
0a1,148
> #include <u.h>
> #include <libc.h>
> #include <thread.h>
> #include <fcall.h>
> #include <9p.h>
> #include "usb.h"
> #include "serial.h"
> 
> enum {
> 	ScACM	= 2,
> 	AT		= 1,
> 	None	= 0,
> };
> 
> static int
> cdcsetparam(Serialport *p)
> {
> 	int res;
> 	uchar vals[7];
> 	Serial *ser;
> 
> 	ser = p->s;
> 
> 	PUT4(vals, p->baud);
> 
> 	vals[4] = 0;
> 	if(p->stop == 1)
> 		vals[4] = 0;
> 	if(p->stop == 15)
> 		vals[4] = 1;
> 	if(p->stop == 2)
> 		vals[4] = 2;
> 
> 	vals[5] = p->parity;
> 
> 	vals[6] = p->bits;
> 
> 	res = usbcmd(ser->dev, Rh2d | Rclass | Riface, 0x20, 0, 0, vals, 7);
> 
> 	return res;
> }
> 
> static int
> cdcinit(Serialport *p)
> {
> 	Serial *ser;
> 
> 	p->baud = 115200;
> 	p->bits = 8;
> 	p->parity = 0;
> 	p->stop = 1;
> 
> 	ser = p->s;
> 
> 	cdcsetparam(p);
> 	incref(ser->dev);
> 	return 0;
> }
> 
> static int
> cdcsetbreak(Serialport *p, int val)
> {
> 	Serial *ser;
> 
> 	ser = p->s;
> 	return usbcmd(ser->dev, Rh2d | Rclass | Riface, 0x23, (val != 0? 0xffff: 0x0000), 0, nil, 0);
> }
> 
> static int
> cdcsendlines(Serialport *p)
> {
> 	if(p->rts)
> 		p->ctlstate |= 0x0002;
> 	else
> 		p->ctlstate &= ~0x0002;
> 	if(p->dtr)
> 		p->ctlstate |= 0x0001;
> 	else
> 		p->ctlstate &= ~0x0001;
> 
> 	return usbcmd(p->s->dev, Rh2d | Rclass | Riface, 0x22, p->ctlstate, 0, nil, 0);
> }
> 
> static int
> cdcclearpipes(Serialport *p)
> {
> 	Serial *ser;
> 
> 	ser = p->s;
> 
> 	if(unstall(ser->dev, p->epout, Eout) < 0)
> 		dprint(2, "serial: unstall epout: %r\n");
> 	if(unstall(ser->dev, p->epin, Ein) < 0)
> 		dprint(2, "serial: unstall epin: %r\n");
> 	if(unstall(ser->dev, p->epintr, Ein) < 0)
> 		dprint(2, "serial: unstall epintr: %r\n");
> 
> 	return 0;
> }
> 
> static int
> cdcwait4data(Serialport *p, uchar *data, int count)
> {
> 	int n;
> 
> 	qunlock(p->s);
> 	while ((n = read(p->epin->dfd, data, count)) == 0)
> 		;
> 	qlock(p->s);
> 
> 	return n;
> }
> 
> static Serialops cdcops = {
> 	.init		= cdcinit,
> 	.setparam	= cdcsetparam,
> 	.setbreak	= cdcsetbreak,
> 	.sendlines	= cdcsendlines,
> 	.clearpipes	= cdcclearpipes,
> 	.wait4data	= cdcwait4data,
> };
> 
> int
> cdcprobe(Serial *ser)
> {
> 	int i, c;
> 	ulong csp;
> 	Usbdev *ud = ser->dev->usb;
> 	Ep *ep;
> 
> 	c = 0;
> 	for (i = 0; i < nelem(ud->ep); i++) {
> 		if ((ep = ud->ep[i]) == nil)
> 			continue;
> 		csp = ep->iface->csp;
> 		if (Class(csp) == Clcomms && Subclass(csp) == ScACM && Proto(csp) == AT)
> 			c++;
> 	}
> 
> 	if (c == 0)
> 		return -1;
> 
> 	ser->nifcs = 1;
> 	ser->outhdrsz = 0;
> 	ser->hasepintr = 1;
> 	ser->Serialops = cdcops;
> 	return 0;
> }
diff -N /sys/src/cmd/nusb/serial/mkfile nusb/serial/mkfile
4c4
< OFILES=ftdi.$O serial.$O prolific.$O ucons.$O silabs.$O ch340.$O
---
> OFILES=ftdi.$O serial.$O prolific.$O ucons.$O silabs.$O ch340.$O cdc.$O
diff -N /sys/src/cmd/nusb/serial/serial.c nusb/serial/serial.c
623a624
> 	int oifc;
624a626
> 	oifc = ifc;
631c633,634
< 	eps = ser->dev->usb->conf[0]->iface[ifc]->ep;
---
> 	do {
> 		eps = ser->dev->usb->conf[0]->iface[oifc]->ep;
633,643c636,647
< 	for(i = 0; i < Nep; i++){
< 		if((ep = eps[i]) == nil)
< 			continue;
< 		if(ser->hasepintr && ep->type == Eintr &&
< 		    ep->dir == Ein && epintr == -1)
< 			epintr = ep->id;
< 		if(ep->type == Ebulk){
< 			if((ep->dir == Ein || ep->dir == Eboth) && epin == -1)
< 				epin = ep->id;
< 			if((ep->dir == Eout || ep->dir == Eboth) && epout == -1)
< 				epout = ep->id;
---
> 		for(i = 0; i < Nep; i++){
> 			if((ep = eps[i]) == nil)
> 				continue;
> 			if(ser->hasepintr && ep->type == Eintr &&
> 			    ep->dir == Ein && epintr == -1)
> 				epintr = ep->id;
> 			if(ep->type == Ebulk){
> 				if((ep->dir == Ein || ep->dir == Eboth) && epin == -1)
> 					epin = ep->id;
> 				if((ep->dir == Eout || ep->dir == Eboth) && epout == -1)
> 					epout = ep->id;
> 			}
645c649
< 	}
---
> 	} while((epin == -1 || epout == -1 || (ser->hasepintr && epintr == -1)) && ++oifc < Niface);
716a721
> extern int cdcprobe(Serial *ser);
753c758,759
< 	&& chprobe(ser))
---
> 	&& chprobe(ser)
> 	&& cdcprobe(ser))