0e77511060c0795680941dc784753f58888ec014
[pandora-kernel.git] / drivers / usb / serial / ch341.c
1 /*
2  * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
3  * Copyright 2007, Werner Cornelius <werner@cornelius-consult.de>
4  * Copyright 2009, Boris Hajduk <boris@hajduk.org>
5  *
6  * ch341.c implements a serial port driver for the Winchiphead CH341.
7  *
8  * The CH341 device can be used to implement an RS232 asynchronous
9  * serial port, an IEEE-1284 parallel printer port or a memory-like
10  * interface. In all cases the CH341 supports an I2C interface as well.
11  * This driver only supports the asynchronous serial interface.
12  *
13  * This program is free software; you can redistribute it and/or
14  * modify it under the terms of the GNU General Public License version
15  * 2 as published by the Free Software Foundation.
16  */
17
18 #include <linux/kernel.h>
19 #include <linux/init.h>
20 #include <linux/tty.h>
21 #include <linux/module.h>
22 #include <linux/slab.h>
23 #include <linux/usb.h>
24 #include <linux/usb/serial.h>
25 #include <linux/serial.h>
26 #include <asm/unaligned.h>
27
28 #define DEFAULT_BAUD_RATE 9600
29 #define DEFAULT_TIMEOUT   1000
30
31 /* flags for IO-Bits */
32 #define CH341_BIT_RTS (1 << 6)
33 #define CH341_BIT_DTR (1 << 5)
34
35 /******************************/
36 /* interrupt pipe definitions */
37 /******************************/
38 /* always 4 interrupt bytes */
39 /* first irq byte normally 0x08 */
40 /* second irq byte base 0x7d + below */
41 /* third irq byte base 0x94 + below */
42 /* fourth irq byte normally 0xee */
43
44 /* second interrupt byte */
45 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
46
47 /* status returned in third interrupt answer byte, inverted in data
48    from irq */
49 #define CH341_BIT_CTS 0x01
50 #define CH341_BIT_DSR 0x02
51 #define CH341_BIT_RI  0x04
52 #define CH341_BIT_DCD 0x08
53 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */
54
55 /*******************************/
56 /* baudrate calculation factor */
57 /*******************************/
58 #define CH341_BAUDBASE_FACTOR 1532620800
59 #define CH341_BAUDBASE_DIVMAX 3
60
61 /* Break support - the information used to implement this was gleaned from
62  * the Net/FreeBSD uchcom.c driver by Takanori Watanabe.  Domo arigato.
63  */
64
65 #define CH341_REQ_WRITE_REG    0x9A
66 #define CH341_REQ_READ_REG     0x95
67 #define CH341_REG_BREAK1       0x05
68 #define CH341_REG_BREAK2       0x18
69 #define CH341_NBREAK_BITS_REG1 0x01
70 #define CH341_NBREAK_BITS_REG2 0x40
71
72
73 static int debug;
74
75 static const struct usb_device_id id_table[] = {
76         { USB_DEVICE(0x4348, 0x5523) },
77         { USB_DEVICE(0x1a86, 0x7523) },
78         { USB_DEVICE(0x1a86, 0x5523) },
79         { },
80 };
81 MODULE_DEVICE_TABLE(usb, id_table);
82
83 struct ch341_private {
84         spinlock_t lock; /* access lock */
85         wait_queue_head_t delta_msr_wait; /* wait queue for modem status */
86         unsigned baud_rate; /* set baud rate */
87         u8 line_control; /* set line control value RTS/DTR */
88         u8 line_status; /* active status of modem control inputs */
89         u8 multi_status_change; /* status changed multiple since last call */
90 };
91
92 static int ch341_control_out(struct usb_device *dev, u8 request,
93                              u16 value, u16 index)
94 {
95         int r;
96         dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40,
97                 (int)request, (int)value, (int)index);
98
99         r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
100                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
101                             value, index, NULL, 0, DEFAULT_TIMEOUT);
102
103         return r;
104 }
105
106 static int ch341_control_in(struct usb_device *dev,
107                             u8 request, u16 value, u16 index,
108                             char *buf, unsigned bufsize)
109 {
110         int r;
111         dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40,
112                 (int)request, (int)value, (int)index, buf, (int)bufsize);
113
114         r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
115                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
116                             value, index, buf, bufsize, DEFAULT_TIMEOUT);
117         return r;
118 }
119
120 static int ch341_set_baudrate(struct usb_device *dev,
121                               struct ch341_private *priv)
122 {
123         short a, b;
124         int r;
125         unsigned long factor;
126         short divisor;
127
128         dbg("ch341_set_baudrate(%d)", priv->baud_rate);
129
130         if (!priv->baud_rate)
131                 return -EINVAL;
132         factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
133         divisor = CH341_BAUDBASE_DIVMAX;
134
135         while ((factor > 0xfff0) && divisor) {
136                 factor >>= 3;
137                 divisor--;
138         }
139
140         if (factor > 0xfff0)
141                 return -EINVAL;
142
143         factor = 0x10000 - factor;
144         a = (factor & 0xff00) | divisor;
145         b = factor & 0xff;
146
147         r = ch341_control_out(dev, 0x9a, 0x1312, a);
148         if (!r)
149                 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
150
151         return r;
152 }
153
154 static int ch341_set_handshake(struct usb_device *dev, u8 control)
155 {
156         dbg("ch341_set_handshake(0x%02x)", control);
157         return ch341_control_out(dev, 0xa4, ~control, 0);
158 }
159
160 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
161 {
162         char *buffer;
163         int r;
164         const unsigned size = 8;
165         unsigned long flags;
166
167         dbg("ch341_get_status()");
168
169         buffer = kmalloc(size, GFP_KERNEL);
170         if (!buffer)
171                 return -ENOMEM;
172
173         r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
174         if (r < 0)
175                 goto out;
176
177         /* setup the private status if available */
178         if (r == 2) {
179                 r = 0;
180                 spin_lock_irqsave(&priv->lock, flags);
181                 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
182                 priv->multi_status_change = 0;
183                 spin_unlock_irqrestore(&priv->lock, flags);
184         } else
185                 r = -EPROTO;
186
187 out:    kfree(buffer);
188         return r;
189 }
190
191 /* -------------------------------------------------------------------------- */
192
193 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
194 {
195         char *buffer;
196         int r;
197         const unsigned size = 8;
198
199         dbg("ch341_configure()");
200
201         buffer = kmalloc(size, GFP_KERNEL);
202         if (!buffer)
203                 return -ENOMEM;
204
205         /* expect two bytes 0x27 0x00 */
206         r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
207         if (r < 0)
208                 goto out;
209
210         r = ch341_control_out(dev, 0xa1, 0, 0);
211         if (r < 0)
212                 goto out;
213
214         r = ch341_set_baudrate(dev, priv);
215         if (r < 0)
216                 goto out;
217
218         /* expect two bytes 0x56 0x00 */
219         r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
220         if (r < 0)
221                 goto out;
222
223         r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
224         if (r < 0)
225                 goto out;
226
227         /* expect 0xff 0xee */
228         r = ch341_get_status(dev, priv);
229         if (r < 0)
230                 goto out;
231
232         r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
233         if (r < 0)
234                 goto out;
235
236         r = ch341_set_baudrate(dev, priv);
237         if (r < 0)
238                 goto out;
239
240         r = ch341_set_handshake(dev, priv->line_control);
241         if (r < 0)
242                 goto out;
243
244         /* expect 0x9f 0xee */
245         r = ch341_get_status(dev, priv);
246
247 out:    kfree(buffer);
248         return r;
249 }
250
251 /* allocate private data */
252 static int ch341_attach(struct usb_serial *serial)
253 {
254         struct ch341_private *priv;
255         int r;
256
257         dbg("ch341_attach()");
258
259         /* private data */
260         priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
261         if (!priv)
262                 return -ENOMEM;
263
264         spin_lock_init(&priv->lock);
265         init_waitqueue_head(&priv->delta_msr_wait);
266         priv->baud_rate = DEFAULT_BAUD_RATE;
267         priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
268
269         r = ch341_configure(serial->dev, priv);
270         if (r < 0)
271                 goto error;
272
273         usb_set_serial_port_data(serial->port[0], priv);
274         return 0;
275
276 error:  kfree(priv);
277         return r;
278 }
279
280 static int ch341_carrier_raised(struct usb_serial_port *port)
281 {
282         struct ch341_private *priv = usb_get_serial_port_data(port);
283         if (priv->line_status & CH341_BIT_DCD)
284                 return 1;
285         return 0;
286 }
287
288 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
289 {
290         struct ch341_private *priv = usb_get_serial_port_data(port);
291         unsigned long flags;
292
293         dbg("%s - port %d", __func__, port->number);
294         /* drop DTR and RTS */
295         spin_lock_irqsave(&priv->lock, flags);
296         if (on)
297                 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
298         else
299                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
300         spin_unlock_irqrestore(&priv->lock, flags);
301         ch341_set_handshake(port->serial->dev, priv->line_control);
302         wake_up_interruptible(&priv->delta_msr_wait);
303 }
304
305 static void ch341_close(struct usb_serial_port *port)
306 {
307         dbg("%s - port %d", __func__, port->number);
308
309         usb_serial_generic_close(port);
310         usb_kill_urb(port->interrupt_in_urb);
311 }
312
313
314 /* open this device, set default parameters */
315 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
316 {
317         struct usb_serial *serial = port->serial;
318         struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
319         int r;
320
321         dbg("ch341_open()");
322
323         priv->baud_rate = DEFAULT_BAUD_RATE;
324
325         r = ch341_configure(serial->dev, priv);
326         if (r)
327                 goto out;
328
329         r = ch341_set_handshake(serial->dev, priv->line_control);
330         if (r)
331                 goto out;
332
333         r = ch341_set_baudrate(serial->dev, priv);
334         if (r)
335                 goto out;
336
337         dbg("%s - submitting interrupt urb", __func__);
338         r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
339         if (r) {
340                 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
341                         " error %d\n", __func__, r);
342                 ch341_close(port);
343                 goto out;
344         }
345
346         r = usb_serial_generic_open(tty, port);
347
348 out:    return r;
349 }
350
351 /* Old_termios contains the original termios settings and
352  * tty->termios contains the new setting to be used.
353  */
354 static void ch341_set_termios(struct tty_struct *tty,
355                 struct usb_serial_port *port, struct ktermios *old_termios)
356 {
357         struct ch341_private *priv = usb_get_serial_port_data(port);
358         unsigned baud_rate;
359         unsigned long flags;
360
361         dbg("ch341_set_termios()");
362
363         baud_rate = tty_get_baud_rate(tty);
364
365         priv->baud_rate = baud_rate;
366
367         if (baud_rate) {
368                 spin_lock_irqsave(&priv->lock, flags);
369                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
370                 spin_unlock_irqrestore(&priv->lock, flags);
371                 ch341_set_baudrate(port->serial->dev, priv);
372         } else {
373                 spin_lock_irqsave(&priv->lock, flags);
374                 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
375                 spin_unlock_irqrestore(&priv->lock, flags);
376         }
377
378         ch341_set_handshake(port->serial->dev, priv->line_control);
379
380         /* Unimplemented:
381          * (cflag & CSIZE) : data bits [5, 8]
382          * (cflag & PARENB) : parity {NONE, EVEN, ODD}
383          * (cflag & CSTOPB) : stop bits [1, 2]
384          */
385 }
386
387 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
388 {
389         const uint16_t ch341_break_reg =
390                 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
391         struct usb_serial_port *port = tty->driver_data;
392         int r;
393         uint16_t reg_contents;
394         uint8_t *break_reg;
395
396         dbg("%s()", __func__);
397
398         break_reg = kmalloc(2, GFP_KERNEL);
399         if (!break_reg) {
400                 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
401                 return;
402         }
403
404         r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
405                         ch341_break_reg, 0, break_reg, 2);
406         if (r < 0) {
407                 dev_err(&port->dev, "%s - USB control read error (%d)\n",
408                                 __func__, r);
409                 goto out;
410         }
411         dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
412                         __func__, break_reg[0], break_reg[1]);
413         if (break_state != 0) {
414                 dbg("%s - Enter break state requested", __func__);
415                 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
416                 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
417         } else {
418                 dbg("%s - Leave break state requested", __func__);
419                 break_reg[0] |= CH341_NBREAK_BITS_REG1;
420                 break_reg[1] |= CH341_NBREAK_BITS_REG2;
421         }
422         dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
423                         __func__, break_reg[0], break_reg[1]);
424         reg_contents = get_unaligned_le16(break_reg);
425         r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
426                         ch341_break_reg, reg_contents);
427         if (r < 0)
428                 dev_err(&port->dev, "%s - USB control write error (%d)\n",
429                                 __func__, r);
430 out:
431         kfree(break_reg);
432 }
433
434 static int ch341_tiocmset(struct tty_struct *tty,
435                           unsigned int set, unsigned int clear)
436 {
437         struct usb_serial_port *port = tty->driver_data;
438         struct ch341_private *priv = usb_get_serial_port_data(port);
439         unsigned long flags;
440         u8 control;
441
442         spin_lock_irqsave(&priv->lock, flags);
443         if (set & TIOCM_RTS)
444                 priv->line_control |= CH341_BIT_RTS;
445         if (set & TIOCM_DTR)
446                 priv->line_control |= CH341_BIT_DTR;
447         if (clear & TIOCM_RTS)
448                 priv->line_control &= ~CH341_BIT_RTS;
449         if (clear & TIOCM_DTR)
450                 priv->line_control &= ~CH341_BIT_DTR;
451         control = priv->line_control;
452         spin_unlock_irqrestore(&priv->lock, flags);
453
454         return ch341_set_handshake(port->serial->dev, control);
455 }
456
457 static void ch341_read_int_callback(struct urb *urb)
458 {
459         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
460         unsigned char *data = urb->transfer_buffer;
461         unsigned int actual_length = urb->actual_length;
462         int status;
463
464         dbg("%s (%d)", __func__, port->number);
465
466         switch (urb->status) {
467         case 0:
468                 /* success */
469                 break;
470         case -ECONNRESET:
471         case -ENOENT:
472         case -ESHUTDOWN:
473                 /* this urb is terminated, clean up */
474                 dbg("%s - urb shutting down with status: %d", __func__,
475                     urb->status);
476                 return;
477         default:
478                 dbg("%s - nonzero urb status received: %d", __func__,
479                     urb->status);
480                 goto exit;
481         }
482
483         usb_serial_debug_data(debug, &port->dev, __func__,
484                               urb->actual_length, urb->transfer_buffer);
485
486         if (actual_length >= 4) {
487                 struct ch341_private *priv = usb_get_serial_port_data(port);
488                 unsigned long flags;
489                 u8 prev_line_status = priv->line_status;
490
491                 spin_lock_irqsave(&priv->lock, flags);
492                 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
493                 if ((data[1] & CH341_MULT_STAT))
494                         priv->multi_status_change = 1;
495                 spin_unlock_irqrestore(&priv->lock, flags);
496
497                 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
498                         struct tty_struct *tty = tty_port_tty_get(&port->port);
499                         if (tty)
500                                 usb_serial_handle_dcd_change(port, tty,
501                                             priv->line_status & CH341_BIT_DCD);
502                         tty_kref_put(tty);
503                 }
504
505                 wake_up_interruptible(&priv->delta_msr_wait);
506         }
507
508 exit:
509         status = usb_submit_urb(urb, GFP_ATOMIC);
510         if (status)
511                 dev_err(&urb->dev->dev,
512                         "%s - usb_submit_urb failed with result %d\n",
513                         __func__, status);
514 }
515
516 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
517 {
518         struct ch341_private *priv = usb_get_serial_port_data(port);
519         unsigned long flags;
520         u8 prevstatus;
521         u8 status;
522         u8 changed;
523         u8 multi_change = 0;
524
525         spin_lock_irqsave(&priv->lock, flags);
526         prevstatus = priv->line_status;
527         priv->multi_status_change = 0;
528         spin_unlock_irqrestore(&priv->lock, flags);
529
530         while (!multi_change) {
531                 interruptible_sleep_on(&priv->delta_msr_wait);
532                 /* see if a signal did it */
533                 if (signal_pending(current))
534                         return -ERESTARTSYS;
535
536                 spin_lock_irqsave(&priv->lock, flags);
537                 status = priv->line_status;
538                 multi_change = priv->multi_status_change;
539                 spin_unlock_irqrestore(&priv->lock, flags);
540
541                 changed = prevstatus ^ status;
542
543                 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
544                     ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
545                     ((arg & TIOCM_CD)  && (changed & CH341_BIT_DCD)) ||
546                     ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
547                         return 0;
548                 }
549                 prevstatus = status;
550         }
551
552         return 0;
553 }
554
555 static int ch341_ioctl(struct tty_struct *tty,
556                         unsigned int cmd, unsigned long arg)
557 {
558         struct usb_serial_port *port = tty->driver_data;
559         dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
560
561         switch (cmd) {
562         case TIOCMIWAIT:
563                 dbg("%s (%d) TIOCMIWAIT", __func__,  port->number);
564                 return wait_modem_info(port, arg);
565
566         default:
567                 dbg("%s not supported = 0x%04x", __func__, cmd);
568                 break;
569         }
570
571         return -ENOIOCTLCMD;
572 }
573
574 static int ch341_tiocmget(struct tty_struct *tty)
575 {
576         struct usb_serial_port *port = tty->driver_data;
577         struct ch341_private *priv = usb_get_serial_port_data(port);
578         unsigned long flags;
579         u8 mcr;
580         u8 status;
581         unsigned int result;
582
583         dbg("%s (%d)", __func__, port->number);
584
585         spin_lock_irqsave(&priv->lock, flags);
586         mcr = priv->line_control;
587         status = priv->line_status;
588         spin_unlock_irqrestore(&priv->lock, flags);
589
590         result = ((mcr & CH341_BIT_DTR)         ? TIOCM_DTR : 0)
591                   | ((mcr & CH341_BIT_RTS)      ? TIOCM_RTS : 0)
592                   | ((status & CH341_BIT_CTS)   ? TIOCM_CTS : 0)
593                   | ((status & CH341_BIT_DSR)   ? TIOCM_DSR : 0)
594                   | ((status & CH341_BIT_RI)    ? TIOCM_RI  : 0)
595                   | ((status & CH341_BIT_DCD)   ? TIOCM_CD  : 0);
596
597         dbg("%s - result = %x", __func__, result);
598
599         return result;
600 }
601
602
603 static int ch341_reset_resume(struct usb_interface *intf)
604 {
605         struct usb_device *dev = interface_to_usbdev(intf);
606         struct usb_serial *serial = NULL;
607         struct ch341_private *priv;
608
609         serial = usb_get_intfdata(intf);
610         priv = usb_get_serial_port_data(serial->port[0]);
611
612         /*reconfigure ch341 serial port after bus-reset*/
613         ch341_configure(dev, priv);
614
615         usb_serial_resume(intf);
616
617         return 0;
618 }
619
620 static struct usb_driver ch341_driver = {
621         .name           = "ch341",
622         .probe          = usb_serial_probe,
623         .disconnect     = usb_serial_disconnect,
624         .suspend        = usb_serial_suspend,
625         .resume         = usb_serial_resume,
626         .reset_resume   = ch341_reset_resume,
627         .id_table       = id_table,
628         .no_dynamic_id  = 1,
629         .supports_autosuspend = 1,
630 };
631
632 static struct usb_serial_driver ch341_device = {
633         .driver = {
634                 .owner  = THIS_MODULE,
635                 .name   = "ch341-uart",
636         },
637         .id_table          = id_table,
638         .usb_driver        = &ch341_driver,
639         .num_ports         = 1,
640         .open              = ch341_open,
641         .dtr_rts           = ch341_dtr_rts,
642         .carrier_raised    = ch341_carrier_raised,
643         .close             = ch341_close,
644         .ioctl             = ch341_ioctl,
645         .set_termios       = ch341_set_termios,
646         .break_ctl         = ch341_break_ctl,
647         .tiocmget          = ch341_tiocmget,
648         .tiocmset          = ch341_tiocmset,
649         .read_int_callback = ch341_read_int_callback,
650         .attach            = ch341_attach,
651 };
652
653 static int __init ch341_init(void)
654 {
655         int retval;
656
657         retval = usb_serial_register(&ch341_device);
658         if (retval)
659                 return retval;
660         retval = usb_register(&ch341_driver);
661         if (retval)
662                 usb_serial_deregister(&ch341_device);
663         return retval;
664 }
665
666 static void __exit ch341_exit(void)
667 {
668         usb_deregister(&ch341_driver);
669         usb_serial_deregister(&ch341_device);
670 }
671
672 module_init(ch341_init);
673 module_exit(ch341_exit);
674 MODULE_LICENSE("GPL");
675
676 module_param(debug, bool, S_IRUGO | S_IWUSR);
677 MODULE_PARM_DESC(debug, "Debug enabled or not");
678
679 /* EOF ch341.c */