Version:  2.6.34 2.6.35 2.6.36 2.6.37 2.6.38 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14

Linux/drivers/usb/serial/ark3116.c

  1 /*
  2  * Copyright (C) 2009 by Bart Hartgers (bart.hartgers+ark3116@gmail.com)
  3  * Original version:
  4  * Copyright (C) 2006
  5  *   Simon Schulz (ark3116_driver <at> auctionant.de)
  6  *
  7  * ark3116
  8  * - implements a driver for the arkmicro ark3116 chipset (vendor=0x6547,
  9  *   productid=0x0232) (used in a datacable called KQ-U8A)
 10  *
 11  * Supports full modem status lines, break, hardware flow control. Does not
 12  * support software flow control, since I do not know how to enable it in hw.
 13  *
 14  * This driver is a essentially new implementation. I initially dug
 15  * into the old ark3116.c driver and suddenly realized the ark3116 is
 16  * a 16450 with a USB interface glued to it. See comments at the
 17  * bottom of this file.
 18  *
 19  * This program is free software; you can redistribute it and/or modify it
 20  * under the terms of the GNU General Public License as published by the
 21  * Free Software Foundation; either version 2 of the License, or (at your
 22  * option) any later version.
 23  */
 24 
 25 #include <linux/kernel.h>
 26 #include <linux/init.h>
 27 #include <linux/ioctl.h>
 28 #include <linux/tty.h>
 29 #include <linux/slab.h>
 30 #include <linux/tty_flip.h>
 31 #include <linux/module.h>
 32 #include <linux/usb.h>
 33 #include <linux/usb/serial.h>
 34 #include <linux/serial.h>
 35 #include <linux/serial_reg.h>
 36 #include <linux/uaccess.h>
 37 #include <linux/mutex.h>
 38 #include <linux/spinlock.h>
 39 
 40 static int debug;
 41 /*
 42  * Version information
 43  */
 44 
 45 #define DRIVER_VERSION "v0.7"
 46 #define DRIVER_AUTHOR "Bart Hartgers <bart.hartgers+ark3116@gmail.com>"
 47 #define DRIVER_DESC "USB ARK3116 serial/IrDA driver"
 48 #define DRIVER_DEV_DESC "ARK3116 RS232/IrDA"
 49 #define DRIVER_NAME "ark3116"
 50 
 51 /* usb timeout of 1 second */
 52 #define ARK_TIMEOUT (1*HZ)
 53 
 54 static const struct usb_device_id id_table[] = {
 55         { USB_DEVICE(0x6547, 0x0232) },
 56         { USB_DEVICE(0x18ec, 0x3118) },         /* USB to IrDA adapter */
 57         { },
 58 };
 59 MODULE_DEVICE_TABLE(usb, id_table);
 60 
 61 static int is_irda(struct usb_serial *serial)
 62 {
 63         struct usb_device *dev = serial->dev;
 64         if (le16_to_cpu(dev->descriptor.idVendor) == 0x18ec &&
 65                         le16_to_cpu(dev->descriptor.idProduct) == 0x3118)
 66                 return 1;
 67         return 0;
 68 }
 69 
 70 struct ark3116_private {
 71         wait_queue_head_t       delta_msr_wait;
 72         struct async_icount     icount;
 73         int                     irda;   /* 1 for irda device */
 74 
 75         /* protects hw register updates */
 76         struct mutex            hw_lock;
 77 
 78         int                     quot;   /* baudrate divisor */
 79         __u32                   lcr;    /* line control register value */
 80         __u32                   hcr;    /* handshake control register (0x8)
 81                                          * value */
 82         __u32                   mcr;    /* modem contol register value */
 83 
 84         /* protects the status values below */
 85         spinlock_t              status_lock;
 86         __u32                   msr;    /* modem status register value */
 87         __u32                   lsr;    /* line status register value */
 88 };
 89 
 90 static int ark3116_write_reg(struct usb_serial *serial,
 91                              unsigned reg, __u8 val)
 92 {
 93         int result;
 94          /* 0xfe 0x40 are magic values taken from original driver */
 95         result = usb_control_msg(serial->dev,
 96                                  usb_sndctrlpipe(serial->dev, 0),
 97                                  0xfe, 0x40, val, reg,
 98                                  NULL, 0, ARK_TIMEOUT);
 99         return result;
100 }
101 
102 static int ark3116_read_reg(struct usb_serial *serial,
103                             unsigned reg, unsigned char *buf)
104 {
105         int result;
106         /* 0xfe 0xc0 are magic values taken from original driver */
107         result = usb_control_msg(serial->dev,
108                                  usb_rcvctrlpipe(serial->dev, 0),
109                                  0xfe, 0xc0, 0, reg,
110                                  buf, 1, ARK_TIMEOUT);
111         if (result < 0)
112                 return result;
113         else
114                 return buf[0];
115 }
116 
117 static inline int calc_divisor(int bps)
118 {
119         /* Original ark3116 made some exceptions in rounding here
120          * because windows did the same. Assume that is not really
121          * necessary.
122          * Crystal is 12MHz, probably because of USB, but we divide by 4?
123          */
124         return (12000000 + 2*bps) / (4*bps);
125 }
126 
127 static int ark3116_attach(struct usb_serial *serial)
128 {
129         struct usb_serial_port *port = serial->port[0];
130         struct ark3116_private *priv;
131 
132         /* make sure we have our end-points */
133         if ((serial->num_bulk_in == 0) ||
134             (serial->num_bulk_out == 0) ||
135             (serial->num_interrupt_in == 0)) {
136                 dev_err(&serial->dev->dev,
137                         "%s - missing endpoint - "
138                         "bulk in: %d, bulk out: %d, int in %d\n",
139                         KBUILD_MODNAME,
140                         serial->num_bulk_in,
141                         serial->num_bulk_out,
142                         serial->num_interrupt_in);
143                 return -EINVAL;
144         }
145 
146         priv = kzalloc(sizeof(struct ark3116_private),
147                        GFP_KERNEL);
148         if (!priv)
149                 return -ENOMEM;
150 
151         init_waitqueue_head(&priv->delta_msr_wait);
152         mutex_init(&priv->hw_lock);
153         spin_lock_init(&priv->status_lock);
154 
155         priv->irda = is_irda(serial);
156 
157         usb_set_serial_port_data(port, priv);
158 
159         /* setup the hardware */
160         ark3116_write_reg(serial, UART_IER, 0);
161         /* disable DMA */
162         ark3116_write_reg(serial, UART_FCR, 0);
163         /* handshake control */
164         priv->hcr = 0;
165         ark3116_write_reg(serial, 0x8     , 0);
166         /* modem control */
167         priv->mcr = 0;
168         ark3116_write_reg(serial, UART_MCR, 0);
169 
170         if (!(priv->irda)) {
171                 ark3116_write_reg(serial, 0xb , 0);
172         } else {
173                 ark3116_write_reg(serial, 0xb , 1);
174                 ark3116_write_reg(serial, 0xc , 0);
175                 ark3116_write_reg(serial, 0xd , 0x41);
176                 ark3116_write_reg(serial, 0xa , 1);
177         }
178 
179         /* setup baudrate */
180         ark3116_write_reg(serial, UART_LCR, UART_LCR_DLAB);
181 
182         /* setup for 9600 8N1 */
183         priv->quot = calc_divisor(9600);
184         ark3116_write_reg(serial, UART_DLL, priv->quot & 0xff);
185         ark3116_write_reg(serial, UART_DLM, (priv->quot>>8) & 0xff);
186 
187         priv->lcr = UART_LCR_WLEN8;
188         ark3116_write_reg(serial, UART_LCR, UART_LCR_WLEN8);
189 
190         ark3116_write_reg(serial, 0xe, 0);
191 
192         if (priv->irda)
193                 ark3116_write_reg(serial, 0x9, 0);
194 
195         dev_info(&serial->dev->dev,
196                 "%s using %s mode\n",
197                 KBUILD_MODNAME,
198                 priv->irda ? "IrDA" : "RS232");
199         return 0;
200 }
201 
202 static void ark3116_release(struct usb_serial *serial)
203 {
204         struct usb_serial_port *port = serial->port[0];
205         struct ark3116_private *priv = usb_get_serial_port_data(port);
206 
207         /* device is closed, so URBs and DMA should be down */
208 
209         usb_set_serial_port_data(port, NULL);
210 
211         mutex_destroy(&priv->hw_lock);
212 
213         kfree(priv);
214 }
215 
216 static void ark3116_init_termios(struct tty_struct *tty)
217 {
218         struct ktermios *termios = tty->termios;
219         *termios = tty_std_termios;
220         termios->c_cflag = B9600 | CS8
221                                       | CREAD | HUPCL | CLOCAL;
222         termios->c_ispeed = 9600;
223         termios->c_ospeed = 9600;
224 }
225 
226 static void ark3116_set_termios(struct tty_struct *tty,
227                                 struct usb_serial_port *port,
228                                 struct ktermios *old_termios)
229 {
230         struct usb_serial *serial = port->serial;
231         struct ark3116_private *priv = usb_get_serial_port_data(port);
232         struct ktermios *termios = tty->termios;
233         unsigned int cflag = termios->c_cflag;
234         int bps = tty_get_baud_rate(tty);
235         int quot;
236         __u8 lcr, hcr, eval;
237 
238         /* set data bit count */
239         switch (cflag & CSIZE) {
240         case CS5:
241                 lcr = UART_LCR_WLEN5;
242                 break;
243         case CS6:
244                 lcr = UART_LCR_WLEN6;
245                 break;
246         case CS7:
247                 lcr = UART_LCR_WLEN7;
248                 break;
249         default:
250         case CS8:
251                 lcr = UART_LCR_WLEN8;
252                 break;
253         }
254         if (cflag & CSTOPB)
255                 lcr |= UART_LCR_STOP;
256         if (cflag & PARENB)
257                 lcr |= UART_LCR_PARITY;
258         if (!(cflag & PARODD))
259                 lcr |= UART_LCR_EPAR;
260 #ifdef CMSPAR
261         if (cflag & CMSPAR)
262                 lcr |= UART_LCR_SPAR;
263 #endif
264         /* handshake control */
265         hcr = (cflag & CRTSCTS) ? 0x03 : 0x00;
266 
267         /* calc baudrate */
268         dbg("%s - setting bps to %d", __func__, bps);
269         eval = 0;
270         switch (bps) {
271         case 0:
272                 quot = calc_divisor(9600);
273                 break;
274         default:
275                 if ((bps < 75) || (bps > 3000000))
276                         bps = 9600;
277                 quot = calc_divisor(bps);
278                 break;
279         case 460800:
280                 eval = 1;
281                 quot = calc_divisor(bps);
282                 break;
283         case 921600:
284                 eval = 2;
285                 quot = calc_divisor(bps);
286                 break;
287         }
288 
289         /* Update state: synchronize */
290         mutex_lock(&priv->hw_lock);
291 
292         /* keep old LCR_SBC bit */
293         lcr |= (priv->lcr & UART_LCR_SBC);
294 
295         dbg("%s - setting hcr:0x%02x,lcr:0x%02x,quot:%d",
296             __func__, hcr, lcr, quot);
297 
298         /* handshake control */
299         if (priv->hcr != hcr) {
300                 priv->hcr = hcr;
301                 ark3116_write_reg(serial, 0x8, hcr);
302         }
303 
304         /* baudrate */
305         if (priv->quot != quot) {
306                 priv->quot = quot;
307                 priv->lcr = lcr; /* need to write lcr anyway */
308 
309                 /* disable DMA since transmit/receive is
310                  * shadowed by UART_DLL
311                  */
312                 ark3116_write_reg(serial, UART_FCR, 0);
313 
314                 ark3116_write_reg(serial, UART_LCR,
315                                   lcr|UART_LCR_DLAB);
316                 ark3116_write_reg(serial, UART_DLL, quot & 0xff);
317                 ark3116_write_reg(serial, UART_DLM, (quot>>8) & 0xff);
318 
319                 /* restore lcr */
320                 ark3116_write_reg(serial, UART_LCR, lcr);
321                 /* magic baudrate thingy: not sure what it does,
322                  * but windows does this as well.
323                  */
324                 ark3116_write_reg(serial, 0xe, eval);
325 
326                 /* enable DMA */
327                 ark3116_write_reg(serial, UART_FCR, UART_FCR_DMA_SELECT);
328         } else if (priv->lcr != lcr) {
329                 priv->lcr = lcr;
330                 ark3116_write_reg(serial, UART_LCR, lcr);
331         }
332 
333         mutex_unlock(&priv->hw_lock);
334 
335         /* check for software flow control */
336         if (I_IXOFF(tty) || I_IXON(tty)) {
337                 dev_warn(&serial->dev->dev,
338                          "%s: don't know how to do software flow control\n",
339                          KBUILD_MODNAME);
340         }
341 
342         /* Don't rewrite B0 */
343         if (tty_termios_baud_rate(termios))
344                 tty_termios_encode_baud_rate(termios, bps, bps);
345 }
346 
347 static void ark3116_close(struct usb_serial_port *port)
348 {
349         struct usb_serial *serial = port->serial;
350 
351         if (serial->dev) {
352                 /* disable DMA */
353                 ark3116_write_reg(serial, UART_FCR, 0);
354 
355                 /* deactivate interrupts */
356                 ark3116_write_reg(serial, UART_IER, 0);
357 
358                 usb_serial_generic_close(port);
359                 if (serial->num_interrupt_in)
360                         usb_kill_urb(port->interrupt_in_urb);
361         }
362 
363 }
364 
365 static int ark3116_open(struct tty_struct *tty, struct usb_serial_port *port)
366 {
367         struct ark3116_private *priv = usb_get_serial_port_data(port);
368         struct usb_serial *serial = port->serial;
369         unsigned char *buf;
370         int result;
371 
372         buf = kmalloc(1, GFP_KERNEL);
373         if (buf == NULL)
374                 return -ENOMEM;
375 
376         result = usb_serial_generic_open(tty, port);
377         if (result) {
378                 dbg("%s - usb_serial_generic_open failed: %d",
379                     __func__, result);
380                 goto err_out;
381         }
382 
383         /* remove any data still left: also clears error state */
384         ark3116_read_reg(serial, UART_RX, buf);
385 
386         /* read modem status */
387         priv->msr = ark3116_read_reg(serial, UART_MSR, buf);
388         /* read line status */
389         priv->lsr = ark3116_read_reg(serial, UART_LSR, buf);
390 
391         result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
392         if (result) {
393                 dev_err(&port->dev, "submit irq_in urb failed %d\n",
394                         result);
395                 ark3116_close(port);
396                 goto err_out;
397         }
398 
399         /* activate interrupts */
400         ark3116_write_reg(port->serial, UART_IER, UART_IER_MSI|UART_IER_RLSI);
401 
402         /* enable DMA */
403         ark3116_write_reg(port->serial, UART_FCR, UART_FCR_DMA_SELECT);
404 
405         /* setup termios */
406         if (tty)
407                 ark3116_set_termios(tty, port, NULL);
408 
409 err_out:
410         kfree(buf);
411         return result;
412 }
413 
414 static int ark3116_get_icount(struct tty_struct *tty,
415                                         struct serial_icounter_struct *icount)
416 {
417         struct usb_serial_port *port = tty->driver_data;
418         struct ark3116_private *priv = usb_get_serial_port_data(port);
419         struct async_icount cnow = priv->icount;
420         icount->cts = cnow.cts;
421         icount->dsr = cnow.dsr;
422         icount->rng = cnow.rng;
423         icount->dcd = cnow.dcd;
424         icount->rx = cnow.rx;
425         icount->tx = cnow.tx;
426         icount->frame = cnow.frame;
427         icount->overrun = cnow.overrun;
428         icount->parity = cnow.parity;
429         icount->brk = cnow.brk;
430         icount->buf_overrun = cnow.buf_overrun;
431         return 0;
432 }
433 
434 static int ark3116_ioctl(struct tty_struct *tty,
435                          unsigned int cmd, unsigned long arg)
436 {
437         struct usb_serial_port *port = tty->driver_data;
438         struct ark3116_private *priv = usb_get_serial_port_data(port);
439         struct serial_struct serstruct;
440         void __user *user_arg = (void __user *)arg;
441 
442         switch (cmd) {
443         case TIOCGSERIAL:
444                 /* XXX: Some of these values are probably wrong. */
445                 memset(&serstruct, 0, sizeof(serstruct));
446                 serstruct.type = PORT_16654;
447                 serstruct.line = port->serial->minor;
448                 serstruct.port = port->number;
449                 serstruct.custom_divisor = 0;
450                 serstruct.baud_base = 460800;
451 
452                 if (copy_to_user(user_arg, &serstruct, sizeof(serstruct)))
453                         return -EFAULT;
454 
455                 return 0;
456         case TIOCSSERIAL:
457                 if (copy_from_user(&serstruct, user_arg, sizeof(serstruct)))
458                         return -EFAULT;
459                 return 0;
460         case TIOCMIWAIT:
461                 for (;;) {
462                         struct async_icount prev = priv->icount;
463                         interruptible_sleep_on(&priv->delta_msr_wait);
464                         /* see if a signal did it */
465                         if (signal_pending(current))
466                                 return -ERESTARTSYS;
467                         if ((prev.rng == priv->icount.rng) &&
468                             (prev.dsr == priv->icount.dsr) &&
469                             (prev.dcd == priv->icount.dcd) &&
470                             (prev.cts == priv->icount.cts))
471                                 return -EIO;
472                         if ((arg & TIOCM_RNG &&
473                              (prev.rng != priv->icount.rng)) ||
474                             (arg & TIOCM_DSR &&
475                              (prev.dsr != priv->icount.dsr)) ||
476                             (arg & TIOCM_CD  &&
477                              (prev.dcd != priv->icount.dcd)) ||
478                             (arg & TIOCM_CTS &&
479                              (prev.cts != priv->icount.cts)))
480                                 return 0;
481                 }
482                 break;
483         }
484 
485         return -ENOIOCTLCMD;
486 }
487 
488 static int ark3116_tiocmget(struct tty_struct *tty)
489 {
490         struct usb_serial_port *port = tty->driver_data;
491         struct ark3116_private *priv = usb_get_serial_port_data(port);
492         __u32 status;
493         __u32 ctrl;
494         unsigned long flags;
495 
496         mutex_lock(&priv->hw_lock);
497         ctrl = priv->mcr;
498         mutex_unlock(&priv->hw_lock);
499 
500         spin_lock_irqsave(&priv->status_lock, flags);
501         status = priv->msr;
502         spin_unlock_irqrestore(&priv->status_lock, flags);
503 
504         return  (status & UART_MSR_DSR  ? TIOCM_DSR  : 0) |
505                 (status & UART_MSR_CTS  ? TIOCM_CTS  : 0) |
506                 (status & UART_MSR_RI   ? TIOCM_RI   : 0) |
507                 (status & UART_MSR_DCD  ? TIOCM_CD   : 0) |
508                 (ctrl   & UART_MCR_DTR  ? TIOCM_DTR  : 0) |
509                 (ctrl   & UART_MCR_RTS  ? TIOCM_RTS  : 0) |
510                 (ctrl   & UART_MCR_OUT1 ? TIOCM_OUT1 : 0) |
511                 (ctrl   & UART_MCR_OUT2 ? TIOCM_OUT2 : 0);
512 }
513 
514 static int ark3116_tiocmset(struct tty_struct *tty,
515                         unsigned set, unsigned clr)
516 {
517         struct usb_serial_port *port = tty->driver_data;
518         struct ark3116_private *priv = usb_get_serial_port_data(port);
519 
520         /* we need to take the mutex here, to make sure that the value
521          * in priv->mcr is actually the one that is in the hardware
522          */
523 
524         mutex_lock(&priv->hw_lock);
525 
526         if (set & TIOCM_RTS)
527                 priv->mcr |= UART_MCR_RTS;
528         if (set & TIOCM_DTR)
529                 priv->mcr |= UART_MCR_DTR;
530         if (set & TIOCM_OUT1)
531                 priv->mcr |= UART_MCR_OUT1;
532         if (set & TIOCM_OUT2)
533                 priv->mcr |= UART_MCR_OUT2;
534         if (clr & TIOCM_RTS)
535                 priv->mcr &= ~UART_MCR_RTS;
536         if (clr & TIOCM_DTR)
537                 priv->mcr &= ~UART_MCR_DTR;
538         if (clr & TIOCM_OUT1)
539                 priv->mcr &= ~UART_MCR_OUT1;
540         if (clr & TIOCM_OUT2)
541                 priv->mcr &= ~UART_MCR_OUT2;
542 
543         ark3116_write_reg(port->serial, UART_MCR, priv->mcr);
544 
545         mutex_unlock(&priv->hw_lock);
546 
547         return 0;
548 }
549 
550 static void ark3116_break_ctl(struct tty_struct *tty, int break_state)
551 {
552         struct usb_serial_port *port = tty->driver_data;
553         struct ark3116_private *priv = usb_get_serial_port_data(port);
554 
555         /* LCR is also used for other things: protect access */
556         mutex_lock(&priv->hw_lock);
557 
558         if (break_state)
559                 priv->lcr |= UART_LCR_SBC;
560         else
561                 priv->lcr &= ~UART_LCR_SBC;
562 
563         ark3116_write_reg(port->serial, UART_LCR, priv->lcr);
564 
565         mutex_unlock(&priv->hw_lock);
566 }
567 
568 static void ark3116_update_msr(struct usb_serial_port *port, __u8 msr)
569 {
570         struct ark3116_private *priv = usb_get_serial_port_data(port);
571         unsigned long flags;
572 
573         spin_lock_irqsave(&priv->status_lock, flags);
574         priv->msr = msr;
575         spin_unlock_irqrestore(&priv->status_lock, flags);
576 
577         if (msr & UART_MSR_ANY_DELTA) {
578                 /* update input line counters */
579                 if (msr & UART_MSR_DCTS)
580                         priv->icount.cts++;
581                 if (msr & UART_MSR_DDSR)
582                         priv->icount.dsr++;
583                 if (msr & UART_MSR_DDCD)
584                         priv->icount.dcd++;
585                 if (msr & UART_MSR_TERI)
586                         priv->icount.rng++;
587                 wake_up_interruptible(&priv->delta_msr_wait);
588         }
589 }
590 
591 static void ark3116_update_lsr(struct usb_serial_port *port, __u8 lsr)
592 {
593         struct ark3116_private *priv = usb_get_serial_port_data(port);
594         unsigned long flags;
595 
596         spin_lock_irqsave(&priv->status_lock, flags);
597         /* combine bits */
598         priv->lsr |= lsr;
599         spin_unlock_irqrestore(&priv->status_lock, flags);
600 
601         if (lsr&UART_LSR_BRK_ERROR_BITS) {
602                 if (lsr & UART_LSR_BI)
603                         priv->icount.brk++;
604                 if (lsr & UART_LSR_FE)
605                         priv->icount.frame++;
606                 if (lsr & UART_LSR_PE)
607                         priv->icount.parity++;
608                 if (lsr & UART_LSR_OE)
609                         priv->icount.overrun++;
610         }
611 }
612 
613 static void ark3116_read_int_callback(struct urb *urb)
614 {
615         struct usb_serial_port *port = urb->context;
616         int status = urb->status;
617         const __u8 *data = urb->transfer_buffer;
618         int result;
619 
620         switch (status) {
621         case -ECONNRESET:
622         case -ENOENT:
623         case -ESHUTDOWN:
624                 /* this urb is terminated, clean up */
625                 dbg("%s - urb shutting down with status: %d",
626                     __func__, status);
627                 return;
628         default:
629                 dbg("%s - nonzero urb status received: %d",
630                     __func__, status);
631                 break;
632         case 0: /* success */
633                 /* discovered this by trail and error... */
634                 if ((urb->actual_length == 4) && (data[0] == 0xe8)) {
635                         const __u8 id = data[1]&UART_IIR_ID;
636                         dbg("%s: iir=%02x", __func__, data[1]);
637                         if (id == UART_IIR_MSI) {
638                                 dbg("%s: msr=%02x", __func__, data[3]);
639                                 ark3116_update_msr(port, data[3]);
640                                 break;
641                         } else if (id == UART_IIR_RLSI) {
642                                 dbg("%s: lsr=%02x", __func__, data[2]);
643                                 ark3116_update_lsr(port, data[2]);
644                                 break;
645                         }
646                 }
647                 /*
648                  * Not sure what this data meant...
649                  */
650                 usb_serial_debug_data(debug, &port->dev,
651                                       __func__,
652                                       urb->actual_length,
653                                       urb->transfer_buffer);
654                 break;
655         }
656 
657         result = usb_submit_urb(urb, GFP_ATOMIC);
658         if (result)
659                 dev_err(&urb->dev->dev,
660                         "%s - Error %d submitting interrupt urb\n",
661                         __func__, result);
662 }
663 
664 
665 /* Data comes in via the bulk (data) URB, erors/interrupts via the int URB.
666  * This means that we cannot be sure which data byte has an associated error
667  * condition, so we report an error for all data in the next bulk read.
668  *
669  * Actually, there might even be a window between the bulk data leaving the
670  * ark and reading/resetting the lsr in the read_bulk_callback where an
671  * interrupt for the next data block could come in.
672  * Without somekind of ordering on the ark, we would have to report the
673  * error for the next block of data as well...
674  * For now, let's pretend this can't happen.
675  */
676 static void ark3116_process_read_urb(struct urb *urb)
677 {
678         struct usb_serial_port *port = urb->context;
679         struct ark3116_private *priv = usb_get_serial_port_data(port);
680         struct tty_struct *tty;
681         unsigned char *data = urb->transfer_buffer;
682         char tty_flag = TTY_NORMAL;
683         unsigned long flags;
684         __u32 lsr;
685 
686         /* update line status */
687         spin_lock_irqsave(&priv->status_lock, flags);
688         lsr = priv->lsr;
689         priv->lsr &= ~UART_LSR_BRK_ERROR_BITS;
690         spin_unlock_irqrestore(&priv->status_lock, flags);
691 
692         if (!urb->actual_length)
693                 return;
694 
695         tty = tty_port_tty_get(&port->port);
696         if (!tty)
697                 return;
698 
699         if (lsr & UART_LSR_BRK_ERROR_BITS) {
700                 if (lsr & UART_LSR_BI)
701                         tty_flag = TTY_BREAK;
702                 else if (lsr & UART_LSR_PE)
703                         tty_flag = TTY_PARITY;
704                 else if (lsr & UART_LSR_FE)
705                         tty_flag = TTY_FRAME;
706 
707                 /* overrun is special, not associated with a char */
708                 if (lsr & UART_LSR_OE)
709                         tty_insert_flip_char(tty, 0, TTY_OVERRUN);
710         }
711         tty_insert_flip_string_fixed_flag(tty, data, tty_flag,
712                                                         urb->actual_length);
713         tty_flip_buffer_push(tty);
714         tty_kref_put(tty);
715 }
716 
717 static struct usb_driver ark3116_driver = {
718         .name =         "ark3116",
719         .probe =        usb_serial_probe,
720         .disconnect =   usb_serial_disconnect,
721         .id_table =     id_table,
722         .no_dynamic_id =        1,
723 };
724 
725 static struct usb_serial_driver ark3116_device = {
726         .driver = {
727                 .owner =        THIS_MODULE,
728                 .name =         "ark3116",
729         },
730         .id_table =             id_table,
731         .usb_driver =           &ark3116_driver,
732         .num_ports =            1,
733         .attach =               ark3116_attach,
734         .release =              ark3116_release,
735         .set_termios =          ark3116_set_termios,
736         .init_termios =         ark3116_init_termios,
737         .ioctl =                ark3116_ioctl,
738         .tiocmget =             ark3116_tiocmget,
739         .tiocmset =             ark3116_tiocmset,
740         .get_icount =           ark3116_get_icount,
741         .open =                 ark3116_open,
742         .close =                ark3116_close,
743         .break_ctl =            ark3116_break_ctl,
744         .read_int_callback =    ark3116_read_int_callback,
745         .process_read_urb =     ark3116_process_read_urb,
746 };
747 
748 static int __init ark3116_init(void)
749 {
750         int retval;
751 
752         retval = usb_serial_register(&ark3116_device);
753         if (retval)
754                 return retval;
755         retval = usb_register(&ark3116_driver);
756         if (retval == 0) {
757                 printk(KERN_INFO "%s:"
758                        DRIVER_VERSION ":"
759                        DRIVER_DESC "\n",
760                        KBUILD_MODNAME);
761         } else
762                 usb_serial_deregister(&ark3116_device);
763         return retval;
764 }
765 
766 static void __exit ark3116_exit(void)
767 {
768         usb_deregister(&ark3116_driver);
769         usb_serial_deregister(&ark3116_device);
770 }
771 
772 module_init(ark3116_init);
773 module_exit(ark3116_exit);
774 MODULE_LICENSE("GPL");
775 
776 MODULE_AUTHOR(DRIVER_AUTHOR);
777 MODULE_DESCRIPTION(DRIVER_DESC);
778 
779 module_param(debug, bool, S_IRUGO | S_IWUSR);
780 MODULE_PARM_DESC(debug, "Enable debug");
781 
782 /*
783  * The following describes what I learned from studying the old
784  * ark3116.c driver, disassembling the windows driver, and some lucky
785  * guesses. Since I do not have any datasheet or other
786  * documentation, inaccuracies are almost guaranteed.
787  *
788  * Some specs for the ARK3116 can be found here:
789  * http://web.archive.org/web/20060318000438/
790  *   www.arkmicro.com/en/products/view.php?id=10
791  * On that page, 2 GPIO pins are mentioned: I assume these are the
792  * OUT1 and OUT2 pins of the UART, so I added support for those
793  * through the MCR. Since the pins are not available on my hardware,
794  * I could not verify this.
795  * Also, it states there is "on-chip hardware flow control". I have
796  * discovered how to enable that. Unfortunately, I do not know how to
797  * enable XON/XOFF (software) flow control, which would need support
798  * from the chip as well to work. Because of the wording on the web
799  * page there is a real possibility the chip simply does not support
800  * software flow control.
801  *
802  * I got my ark3116 as part of a mobile phone adapter cable. On the
803  * PCB, the following numbered contacts are present:
804  *
805  *  1:- +5V
806  *  2:o DTR
807  *  3:i RX
808  *  4:i DCD
809  *  5:o RTS
810  *  6:o TX
811  *  7:i RI
812  *  8:i DSR
813  * 10:- 0V
814  * 11:i CTS
815  *
816  * On my chip, all signals seem to be 3.3V, but 5V tolerant. But that
817  * may be different for the one you have ;-).
818  *
819  * The windows driver limits the registers to 0-F, so I assume there
820  * are actually 16 present on the device.
821  *
822  * On an UART interrupt, 4 bytes of data come in on the interrupt
823  * endpoint. The bytes are 0xe8 IIR LSR MSR.
824  *
825  * The baudrate seems to be generated from the 12MHz crystal, using
826  * 4-times subsampling. So quot=12e6/(4*baud). Also see description
827  * of register E.
828  *
829  * Registers 0-7:
830  * These seem to be the same as for a regular 16450. The FCR is set
831  * to UART_FCR_DMA_SELECT (0x8), I guess to enable transfers between
832  * the UART and the USB bridge/DMA engine.
833  *
834  * Register 8:
835  * By trial and error, I found out that bit 0 enables hardware CTS,
836  * stopping TX when CTS is +5V. Bit 1 does the same for RTS, making
837  * RTS +5V when the 3116 cannot transfer the data to the USB bus
838  * (verified by disabling the reading URB). Note that as far as I can
839  * tell, the windows driver does NOT use this, so there might be some
840  * hardware bug or something.
841  *
842  * According to a patch provided here
843  * (http://lkml.org/lkml/2009/7/26/56), the ARK3116 can also be used
844  * as an IrDA dongle. Since I do not have such a thing, I could not
845  * investigate that aspect. However, I can speculate ;-).
846  *
847  * - IrDA encodes data differently than RS232. Most likely, one of
848  *   the bits in registers 9..E enables the IR ENDEC (encoder/decoder).
849  * - Depending on the IR transceiver, the input and output need to be
850  *   inverted, so there are probably bits for that as well.
851  * - IrDA is half-duplex, so there should be a bit for selecting that.
852  *
853  * This still leaves at least two registers unaccounted for. Perhaps
854  * The chip can do XON/XOFF or CRC in HW?
855  *
856  * Register 9:
857  * Set to 0x00 for IrDA, when the baudrate is initialised.
858  *
859  * Register A:
860  * Set to 0x01 for IrDA, at init.
861  *
862  * Register B:
863  * Set to 0x01 for IrDA, 0x00 for RS232, at init.
864  *
865  * Register C:
866  * Set to 00 for IrDA, at init.
867  *
868  * Register D:
869  * Set to 0x41 for IrDA, at init.
870  *
871  * Register E:
872  * Somekind of baudrate override. The windows driver seems to set
873  * this to 0x00 for normal baudrates, 0x01 for 460800, 0x02 for 921600.
874  * Since 460800 and 921600 cannot be obtained by dividing 3MHz by an integer,
875  * it could be somekind of subdivisor thingy.
876  * However,it does not seem to do anything: selecting 921600 (divisor 3,
877  * reg E=2), still gets 1 MHz. I also checked if registers 9, C or F would
878  * work, but they don't.
879  *
880  * Register F: unknown
881  */
882 

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