Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/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/tty.h>
 20 #include <linux/module.h>
 21 #include <linux/slab.h>
 22 #include <linux/usb.h>
 23 #include <linux/usb/serial.h>
 24 #include <linux/serial.h>
 25 #include <asm/unaligned.h>
 26 
 27 #define DEFAULT_BAUD_RATE 9600
 28 #define DEFAULT_TIMEOUT   1000
 29 
 30 /* flags for IO-Bits */
 31 #define CH341_BIT_RTS (1 << 6)
 32 #define CH341_BIT_DTR (1 << 5)
 33 
 34 /******************************/
 35 /* interrupt pipe definitions */
 36 /******************************/
 37 /* always 4 interrupt bytes */
 38 /* first irq byte normally 0x08 */
 39 /* second irq byte base 0x7d + below */
 40 /* third irq byte base 0x94 + below */
 41 /* fourth irq byte normally 0xee */
 42 
 43 /* second interrupt byte */
 44 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
 45 
 46 /* status returned in third interrupt answer byte, inverted in data
 47    from irq */
 48 #define CH341_BIT_CTS 0x01
 49 #define CH341_BIT_DSR 0x02
 50 #define CH341_BIT_RI  0x04
 51 #define CH341_BIT_DCD 0x08
 52 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */
 53 
 54 /*******************************/
 55 /* baudrate calculation factor */
 56 /*******************************/
 57 #define CH341_BAUDBASE_FACTOR 1532620800
 58 #define CH341_BAUDBASE_DIVMAX 3
 59 
 60 /* Break support - the information used to implement this was gleaned from
 61  * the Net/FreeBSD uchcom.c driver by Takanori Watanabe.  Domo arigato.
 62  */
 63 
 64 #define CH341_REQ_READ_VERSION 0x5F
 65 #define CH341_REQ_WRITE_REG    0x9A
 66 #define CH341_REQ_READ_REG     0x95
 67 #define CH341_REQ_SERIAL_INIT  0xA1
 68 #define CH341_REQ_MODEM_CTRL   0xA4
 69 
 70 #define CH341_REG_BREAK        0x05
 71 #define CH341_REG_LCR          0x18
 72 #define CH341_NBREAK_BITS      0x01
 73 
 74 #define CH341_LCR_ENABLE_RX    0x80
 75 #define CH341_LCR_ENABLE_TX    0x40
 76 #define CH341_LCR_MARK_SPACE   0x20
 77 #define CH341_LCR_PAR_EVEN     0x10
 78 #define CH341_LCR_ENABLE_PAR   0x08
 79 #define CH341_LCR_STOP_BITS_2  0x04
 80 #define CH341_LCR_CS8          0x03
 81 #define CH341_LCR_CS7          0x02
 82 #define CH341_LCR_CS6          0x01
 83 #define CH341_LCR_CS5          0x00
 84 
 85 static const struct usb_device_id id_table[] = {
 86         { USB_DEVICE(0x4348, 0x5523) },
 87         { USB_DEVICE(0x1a86, 0x7523) },
 88         { USB_DEVICE(0x1a86, 0x5523) },
 89         { },
 90 };
 91 MODULE_DEVICE_TABLE(usb, id_table);
 92 
 93 struct ch341_private {
 94         spinlock_t lock; /* access lock */
 95         unsigned baud_rate; /* set baud rate */
 96         u8 line_control; /* set line control value RTS/DTR */
 97         u8 line_status; /* active status of modem control inputs */
 98         u8 lcr;
 99 };
100 
101 static void ch341_set_termios(struct tty_struct *tty,
102                               struct usb_serial_port *port,
103                               struct ktermios *old_termios);
104 
105 static int ch341_control_out(struct usb_device *dev, u8 request,
106                              u16 value, u16 index)
107 {
108         int r;
109 
110         dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
111                 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index);
112 
113         r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
114                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
115                             value, index, NULL, 0, DEFAULT_TIMEOUT);
116         if (r < 0)
117                 dev_err(&dev->dev, "failed to send control message: %d\n", r);
118 
119         return r;
120 }
121 
122 static int ch341_control_in(struct usb_device *dev,
123                             u8 request, u16 value, u16 index,
124                             char *buf, unsigned bufsize)
125 {
126         int r;
127 
128         dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
129                 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf,
130                 (int)bufsize);
131 
132         r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
133                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
134                             value, index, buf, bufsize, DEFAULT_TIMEOUT);
135         if (r < bufsize) {
136                 if (r >= 0) {
137                         dev_err(&dev->dev,
138                                 "short control message received (%d < %u)\n",
139                                 r, bufsize);
140                         r = -EIO;
141                 }
142 
143                 dev_err(&dev->dev, "failed to receive control message: %d\n",
144                         r);
145                 return r;
146         }
147 
148         return 0;
149 }
150 
151 static int ch341_set_baudrate_lcr(struct usb_device *dev,
152                                   struct ch341_private *priv, u8 lcr)
153 {
154         short a;
155         int r;
156         unsigned long factor;
157         short divisor;
158 
159         if (!priv->baud_rate)
160                 return -EINVAL;
161         factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
162         divisor = CH341_BAUDBASE_DIVMAX;
163 
164         while ((factor > 0xfff0) && divisor) {
165                 factor >>= 3;
166                 divisor--;
167         }
168 
169         if (factor > 0xfff0)
170                 return -EINVAL;
171 
172         factor = 0x10000 - factor;
173         a = (factor & 0xff00) | divisor;
174 
175         /*
176          * CH341A buffers data until a full endpoint-size packet (32 bytes)
177          * has been received unless bit 7 is set.
178          */
179         a |= BIT(7);
180 
181         r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x1312, a);
182         if (r)
183                 return r;
184 
185         r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, lcr);
186         if (r)
187                 return r;
188 
189         return r;
190 }
191 
192 static int ch341_set_handshake(struct usb_device *dev, u8 control)
193 {
194         return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0);
195 }
196 
197 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
198 {
199         const unsigned int size = 2;
200         char *buffer;
201         int r;
202         unsigned long flags;
203 
204         buffer = kmalloc(size, GFP_KERNEL);
205         if (!buffer)
206                 return -ENOMEM;
207 
208         r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
209         if (r < 0)
210                 goto out;
211 
212         spin_lock_irqsave(&priv->lock, flags);
213         priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
214         spin_unlock_irqrestore(&priv->lock, flags);
215 
216 out:    kfree(buffer);
217         return r;
218 }
219 
220 /* -------------------------------------------------------------------------- */
221 
222 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
223 {
224         const unsigned int size = 2;
225         char *buffer;
226         int r;
227 
228         buffer = kmalloc(size, GFP_KERNEL);
229         if (!buffer)
230                 return -ENOMEM;
231 
232         /* expect two bytes 0x27 0x00 */
233         r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
234         if (r < 0)
235                 goto out;
236         dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]);
237 
238         r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
239         if (r < 0)
240                 goto out;
241 
242         /* expect two bytes 0x56 0x00 */
243         r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x2518, 0, buffer, size);
244         if (r < 0)
245                 goto out;
246 
247         r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, 0x0050);
248         if (r < 0)
249                 goto out;
250 
251         /* expect 0xff 0xee */
252         r = ch341_get_status(dev, priv);
253         if (r < 0)
254                 goto out;
255 
256         r = ch341_set_baudrate_lcr(dev, priv, priv->lcr);
257         if (r < 0)
258                 goto out;
259 
260         r = ch341_set_handshake(dev, priv->line_control);
261         if (r < 0)
262                 goto out;
263 
264         /* expect 0x9f 0xee */
265         r = ch341_get_status(dev, priv);
266 
267 out:    kfree(buffer);
268         return r;
269 }
270 
271 static int ch341_port_probe(struct usb_serial_port *port)
272 {
273         struct ch341_private *priv;
274         int r;
275 
276         priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
277         if (!priv)
278                 return -ENOMEM;
279 
280         spin_lock_init(&priv->lock);
281         priv->baud_rate = DEFAULT_BAUD_RATE;
282 
283         r = ch341_configure(port->serial->dev, priv);
284         if (r < 0)
285                 goto error;
286 
287         usb_set_serial_port_data(port, priv);
288         return 0;
289 
290 error:  kfree(priv);
291         return r;
292 }
293 
294 static int ch341_port_remove(struct usb_serial_port *port)
295 {
296         struct ch341_private *priv;
297 
298         priv = usb_get_serial_port_data(port);
299         kfree(priv);
300 
301         return 0;
302 }
303 
304 static int ch341_carrier_raised(struct usb_serial_port *port)
305 {
306         struct ch341_private *priv = usb_get_serial_port_data(port);
307         if (priv->line_status & CH341_BIT_DCD)
308                 return 1;
309         return 0;
310 }
311 
312 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
313 {
314         struct ch341_private *priv = usb_get_serial_port_data(port);
315         unsigned long flags;
316 
317         /* drop DTR and RTS */
318         spin_lock_irqsave(&priv->lock, flags);
319         if (on)
320                 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
321         else
322                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
323         spin_unlock_irqrestore(&priv->lock, flags);
324         ch341_set_handshake(port->serial->dev, priv->line_control);
325 }
326 
327 static void ch341_close(struct usb_serial_port *port)
328 {
329         usb_serial_generic_close(port);
330         usb_kill_urb(port->interrupt_in_urb);
331 }
332 
333 
334 /* open this device, set default parameters */
335 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
336 {
337         struct usb_serial *serial = port->serial;
338         struct ch341_private *priv = usb_get_serial_port_data(port);
339         int r;
340 
341         r = ch341_configure(serial->dev, priv);
342         if (r)
343                 return r;
344 
345         if (tty)
346                 ch341_set_termios(tty, port, NULL);
347 
348         dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__);
349         r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
350         if (r) {
351                 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n",
352                         __func__, r);
353                 return r;
354         }
355 
356         r = usb_serial_generic_open(tty, port);
357         if (r)
358                 goto err_kill_interrupt_urb;
359 
360         return 0;
361 
362 err_kill_interrupt_urb:
363         usb_kill_urb(port->interrupt_in_urb);
364 
365         return r;
366 }
367 
368 /* Old_termios contains the original termios settings and
369  * tty->termios contains the new setting to be used.
370  */
371 static void ch341_set_termios(struct tty_struct *tty,
372                 struct usb_serial_port *port, struct ktermios *old_termios)
373 {
374         struct ch341_private *priv = usb_get_serial_port_data(port);
375         unsigned baud_rate;
376         unsigned long flags;
377         unsigned char ctrl;
378         int r;
379 
380         /* redundant changes may cause the chip to lose bytes */
381         if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
382                 return;
383 
384         baud_rate = tty_get_baud_rate(tty);
385 
386         ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX;
387 
388         switch (C_CSIZE(tty)) {
389         case CS5:
390                 ctrl |= CH341_LCR_CS5;
391                 break;
392         case CS6:
393                 ctrl |= CH341_LCR_CS6;
394                 break;
395         case CS7:
396                 ctrl |= CH341_LCR_CS7;
397                 break;
398         case CS8:
399                 ctrl |= CH341_LCR_CS8;
400                 break;
401         }
402 
403         if (C_PARENB(tty)) {
404                 ctrl |= CH341_LCR_ENABLE_PAR;
405                 if (C_PARODD(tty) == 0)
406                         ctrl |= CH341_LCR_PAR_EVEN;
407                 if (C_CMSPAR(tty))
408                         ctrl |= CH341_LCR_MARK_SPACE;
409         }
410 
411         if (C_CSTOPB(tty))
412                 ctrl |= CH341_LCR_STOP_BITS_2;
413 
414         if (baud_rate) {
415                 priv->baud_rate = baud_rate;
416 
417                 r = ch341_set_baudrate_lcr(port->serial->dev, priv, ctrl);
418                 if (r < 0 && old_termios) {
419                         priv->baud_rate = tty_termios_baud_rate(old_termios);
420                         tty_termios_copy_hw(&tty->termios, old_termios);
421                 } else if (r == 0) {
422                         priv->lcr = ctrl;
423                 }
424         }
425 
426         spin_lock_irqsave(&priv->lock, flags);
427         if (C_BAUD(tty) == B0)
428                 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
429         else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
430                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
431         spin_unlock_irqrestore(&priv->lock, flags);
432 
433         ch341_set_handshake(port->serial->dev, priv->line_control);
434 }
435 
436 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
437 {
438         const uint16_t ch341_break_reg =
439                         ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
440         struct usb_serial_port *port = tty->driver_data;
441         int r;
442         uint16_t reg_contents;
443         uint8_t *break_reg;
444 
445         break_reg = kmalloc(2, GFP_KERNEL);
446         if (!break_reg)
447                 return;
448 
449         r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
450                         ch341_break_reg, 0, break_reg, 2);
451         if (r < 0) {
452                 dev_err(&port->dev, "%s - USB control read error (%d)\n",
453                                 __func__, r);
454                 goto out;
455         }
456         dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
457                 __func__, break_reg[0], break_reg[1]);
458         if (break_state != 0) {
459                 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
460                 break_reg[0] &= ~CH341_NBREAK_BITS;
461                 break_reg[1] &= ~CH341_LCR_ENABLE_TX;
462         } else {
463                 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
464                 break_reg[0] |= CH341_NBREAK_BITS;
465                 break_reg[1] |= CH341_LCR_ENABLE_TX;
466         }
467         dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
468                 __func__, break_reg[0], break_reg[1]);
469         reg_contents = get_unaligned_le16(break_reg);
470         r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
471                         ch341_break_reg, reg_contents);
472         if (r < 0)
473                 dev_err(&port->dev, "%s - USB control write error (%d)\n",
474                                 __func__, r);
475 out:
476         kfree(break_reg);
477 }
478 
479 static int ch341_tiocmset(struct tty_struct *tty,
480                           unsigned int set, unsigned int clear)
481 {
482         struct usb_serial_port *port = tty->driver_data;
483         struct ch341_private *priv = usb_get_serial_port_data(port);
484         unsigned long flags;
485         u8 control;
486 
487         spin_lock_irqsave(&priv->lock, flags);
488         if (set & TIOCM_RTS)
489                 priv->line_control |= CH341_BIT_RTS;
490         if (set & TIOCM_DTR)
491                 priv->line_control |= CH341_BIT_DTR;
492         if (clear & TIOCM_RTS)
493                 priv->line_control &= ~CH341_BIT_RTS;
494         if (clear & TIOCM_DTR)
495                 priv->line_control &= ~CH341_BIT_DTR;
496         control = priv->line_control;
497         spin_unlock_irqrestore(&priv->lock, flags);
498 
499         return ch341_set_handshake(port->serial->dev, control);
500 }
501 
502 static void ch341_update_line_status(struct usb_serial_port *port,
503                                         unsigned char *data, size_t len)
504 {
505         struct ch341_private *priv = usb_get_serial_port_data(port);
506         struct tty_struct *tty;
507         unsigned long flags;
508         u8 status;
509         u8 delta;
510 
511         if (len < 4)
512                 return;
513 
514         status = ~data[2] & CH341_BITS_MODEM_STAT;
515 
516         spin_lock_irqsave(&priv->lock, flags);
517         delta = status ^ priv->line_status;
518         priv->line_status = status;
519         spin_unlock_irqrestore(&priv->lock, flags);
520 
521         if (data[1] & CH341_MULT_STAT)
522                 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
523 
524         if (!delta)
525                 return;
526 
527         if (delta & CH341_BIT_CTS)
528                 port->icount.cts++;
529         if (delta & CH341_BIT_DSR)
530                 port->icount.dsr++;
531         if (delta & CH341_BIT_RI)
532                 port->icount.rng++;
533         if (delta & CH341_BIT_DCD) {
534                 port->icount.dcd++;
535                 tty = tty_port_tty_get(&port->port);
536                 if (tty) {
537                         usb_serial_handle_dcd_change(port, tty,
538                                                 status & CH341_BIT_DCD);
539                         tty_kref_put(tty);
540                 }
541         }
542 
543         wake_up_interruptible(&port->port.delta_msr_wait);
544 }
545 
546 static void ch341_read_int_callback(struct urb *urb)
547 {
548         struct usb_serial_port *port = urb->context;
549         unsigned char *data = urb->transfer_buffer;
550         unsigned int len = urb->actual_length;
551         int status;
552 
553         switch (urb->status) {
554         case 0:
555                 /* success */
556                 break;
557         case -ECONNRESET:
558         case -ENOENT:
559         case -ESHUTDOWN:
560                 /* this urb is terminated, clean up */
561                 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
562                         __func__, urb->status);
563                 return;
564         default:
565                 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
566                         __func__, urb->status);
567                 goto exit;
568         }
569 
570         usb_serial_debug_data(&port->dev, __func__, len, data);
571         ch341_update_line_status(port, data, len);
572 exit:
573         status = usb_submit_urb(urb, GFP_ATOMIC);
574         if (status) {
575                 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
576                         __func__, status);
577         }
578 }
579 
580 static int ch341_tiocmget(struct tty_struct *tty)
581 {
582         struct usb_serial_port *port = tty->driver_data;
583         struct ch341_private *priv = usb_get_serial_port_data(port);
584         unsigned long flags;
585         u8 mcr;
586         u8 status;
587         unsigned int result;
588 
589         spin_lock_irqsave(&priv->lock, flags);
590         mcr = priv->line_control;
591         status = priv->line_status;
592         spin_unlock_irqrestore(&priv->lock, flags);
593 
594         result = ((mcr & CH341_BIT_DTR)         ? TIOCM_DTR : 0)
595                   | ((mcr & CH341_BIT_RTS)      ? TIOCM_RTS : 0)
596                   | ((status & CH341_BIT_CTS)   ? TIOCM_CTS : 0)
597                   | ((status & CH341_BIT_DSR)   ? TIOCM_DSR : 0)
598                   | ((status & CH341_BIT_RI)    ? TIOCM_RI  : 0)
599                   | ((status & CH341_BIT_DCD)   ? TIOCM_CD  : 0);
600 
601         dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
602 
603         return result;
604 }
605 
606 static int ch341_reset_resume(struct usb_serial *serial)
607 {
608         struct usb_serial_port *port = serial->port[0];
609         struct ch341_private *priv = usb_get_serial_port_data(port);
610         int ret;
611 
612         /* reconfigure ch341 serial port after bus-reset */
613         ch341_configure(serial->dev, priv);
614 
615         if (tty_port_initialized(&port->port)) {
616                 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
617                 if (ret) {
618                         dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
619                                 ret);
620                         return ret;
621                 }
622         }
623 
624         return usb_serial_generic_resume(serial);
625 }
626 
627 static struct usb_serial_driver ch341_device = {
628         .driver = {
629                 .owner  = THIS_MODULE,
630                 .name   = "ch341-uart",
631         },
632         .id_table          = id_table,
633         .num_ports         = 1,
634         .open              = ch341_open,
635         .dtr_rts           = ch341_dtr_rts,
636         .carrier_raised    = ch341_carrier_raised,
637         .close             = ch341_close,
638         .set_termios       = ch341_set_termios,
639         .break_ctl         = ch341_break_ctl,
640         .tiocmget          = ch341_tiocmget,
641         .tiocmset          = ch341_tiocmset,
642         .tiocmiwait        = usb_serial_generic_tiocmiwait,
643         .read_int_callback = ch341_read_int_callback,
644         .port_probe        = ch341_port_probe,
645         .port_remove       = ch341_port_remove,
646         .reset_resume      = ch341_reset_resume,
647 };
648 
649 static struct usb_serial_driver * const serial_drivers[] = {
650         &ch341_device, NULL
651 };
652 
653 module_usb_serial_driver(serial_drivers, id_table);
654 
655 MODULE_LICENSE("GPL");
656 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us