Version:  2.0.40 2.2.26 2.4.37 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1

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_WRITE_REG    0x9A
 65 #define CH341_REQ_READ_REG     0x95
 66 #define CH341_REG_BREAK1       0x05
 67 #define CH341_REG_BREAK2       0x18
 68 #define CH341_NBREAK_BITS_REG1 0x01
 69 #define CH341_NBREAK_BITS_REG2 0x40
 70 
 71 
 72 static const struct usb_device_id id_table[] = {
 73         { USB_DEVICE(0x4348, 0x5523) },
 74         { USB_DEVICE(0x1a86, 0x7523) },
 75         { USB_DEVICE(0x1a86, 0x5523) },
 76         { },
 77 };
 78 MODULE_DEVICE_TABLE(usb, id_table);
 79 
 80 struct ch341_private {
 81         spinlock_t lock; /* access lock */
 82         unsigned baud_rate; /* set baud rate */
 83         u8 line_control; /* set line control value RTS/DTR */
 84         u8 line_status; /* active status of modem control inputs */
 85 };
 86 
 87 static void ch341_set_termios(struct tty_struct *tty,
 88                               struct usb_serial_port *port,
 89                               struct ktermios *old_termios);
 90 
 91 static int ch341_control_out(struct usb_device *dev, u8 request,
 92                              u16 value, u16 index)
 93 {
 94         int r;
 95 
 96         dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
 97                 USB_DIR_OUT|0x40, (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 
112         dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
113                 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf,
114                 (int)bufsize);
115 
116         r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
117                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
118                             value, index, buf, bufsize, DEFAULT_TIMEOUT);
119         return r;
120 }
121 
122 static int ch341_set_baudrate(struct usb_device *dev,
123                               struct ch341_private *priv)
124 {
125         short a, b;
126         int r;
127         unsigned long factor;
128         short divisor;
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         return ch341_control_out(dev, 0xa4, ~control, 0);
157 }
158 
159 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
160 {
161         char *buffer;
162         int r;
163         const unsigned size = 8;
164         unsigned long flags;
165 
166         buffer = kmalloc(size, GFP_KERNEL);
167         if (!buffer)
168                 return -ENOMEM;
169 
170         r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
171         if (r < 0)
172                 goto out;
173 
174         /* setup the private status if available */
175         if (r == 2) {
176                 r = 0;
177                 spin_lock_irqsave(&priv->lock, flags);
178                 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
179                 spin_unlock_irqrestore(&priv->lock, flags);
180         } else
181                 r = -EPROTO;
182 
183 out:    kfree(buffer);
184         return r;
185 }
186 
187 /* -------------------------------------------------------------------------- */
188 
189 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
190 {
191         char *buffer;
192         int r;
193         const unsigned size = 8;
194 
195         buffer = kmalloc(size, GFP_KERNEL);
196         if (!buffer)
197                 return -ENOMEM;
198 
199         /* expect two bytes 0x27 0x00 */
200         r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
201         if (r < 0)
202                 goto out;
203 
204         r = ch341_control_out(dev, 0xa1, 0, 0);
205         if (r < 0)
206                 goto out;
207 
208         r = ch341_set_baudrate(dev, priv);
209         if (r < 0)
210                 goto out;
211 
212         /* expect two bytes 0x56 0x00 */
213         r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
214         if (r < 0)
215                 goto out;
216 
217         r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
218         if (r < 0)
219                 goto out;
220 
221         /* expect 0xff 0xee */
222         r = ch341_get_status(dev, priv);
223         if (r < 0)
224                 goto out;
225 
226         r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
227         if (r < 0)
228                 goto out;
229 
230         r = ch341_set_baudrate(dev, priv);
231         if (r < 0)
232                 goto out;
233 
234         r = ch341_set_handshake(dev, priv->line_control);
235         if (r < 0)
236                 goto out;
237 
238         /* expect 0x9f 0xee */
239         r = ch341_get_status(dev, priv);
240 
241 out:    kfree(buffer);
242         return r;
243 }
244 
245 static int ch341_port_probe(struct usb_serial_port *port)
246 {
247         struct ch341_private *priv;
248         int r;
249 
250         priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
251         if (!priv)
252                 return -ENOMEM;
253 
254         spin_lock_init(&priv->lock);
255         priv->baud_rate = DEFAULT_BAUD_RATE;
256         priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
257 
258         r = ch341_configure(port->serial->dev, priv);
259         if (r < 0)
260                 goto error;
261 
262         usb_set_serial_port_data(port, priv);
263         return 0;
264 
265 error:  kfree(priv);
266         return r;
267 }
268 
269 static int ch341_port_remove(struct usb_serial_port *port)
270 {
271         struct ch341_private *priv;
272 
273         priv = usb_get_serial_port_data(port);
274         kfree(priv);
275 
276         return 0;
277 }
278 
279 static int ch341_carrier_raised(struct usb_serial_port *port)
280 {
281         struct ch341_private *priv = usb_get_serial_port_data(port);
282         if (priv->line_status & CH341_BIT_DCD)
283                 return 1;
284         return 0;
285 }
286 
287 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
288 {
289         struct ch341_private *priv = usb_get_serial_port_data(port);
290         unsigned long flags;
291 
292         /* drop DTR and RTS */
293         spin_lock_irqsave(&priv->lock, flags);
294         if (on)
295                 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
296         else
297                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
298         spin_unlock_irqrestore(&priv->lock, flags);
299         ch341_set_handshake(port->serial->dev, priv->line_control);
300 }
301 
302 static void ch341_close(struct usb_serial_port *port)
303 {
304         usb_serial_generic_close(port);
305         usb_kill_urb(port->interrupt_in_urb);
306 }
307 
308 
309 /* open this device, set default parameters */
310 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
311 {
312         struct usb_serial *serial = port->serial;
313         struct ch341_private *priv = usb_get_serial_port_data(port);
314         int r;
315 
316         r = ch341_configure(serial->dev, priv);
317         if (r)
318                 goto out;
319 
320         if (tty)
321                 ch341_set_termios(tty, port, NULL);
322 
323         dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__);
324         r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
325         if (r) {
326                 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n",
327                         __func__, r);
328                 goto out;
329         }
330 
331         r = usb_serial_generic_open(tty, port);
332 
333 out:    return r;
334 }
335 
336 /* Old_termios contains the original termios settings and
337  * tty->termios contains the new setting to be used.
338  */
339 static void ch341_set_termios(struct tty_struct *tty,
340                 struct usb_serial_port *port, struct ktermios *old_termios)
341 {
342         struct ch341_private *priv = usb_get_serial_port_data(port);
343         unsigned baud_rate;
344         unsigned long flags;
345 
346         baud_rate = tty_get_baud_rate(tty);
347 
348         priv->baud_rate = baud_rate;
349 
350         if (baud_rate) {
351                 spin_lock_irqsave(&priv->lock, flags);
352                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
353                 spin_unlock_irqrestore(&priv->lock, flags);
354                 ch341_set_baudrate(port->serial->dev, priv);
355         } else {
356                 spin_lock_irqsave(&priv->lock, flags);
357                 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
358                 spin_unlock_irqrestore(&priv->lock, flags);
359         }
360 
361         ch341_set_handshake(port->serial->dev, priv->line_control);
362 
363         /* Unimplemented:
364          * (cflag & CSIZE) : data bits [5, 8]
365          * (cflag & PARENB) : parity {NONE, EVEN, ODD}
366          * (cflag & CSTOPB) : stop bits [1, 2]
367          */
368 }
369 
370 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
371 {
372         const uint16_t ch341_break_reg =
373                 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
374         struct usb_serial_port *port = tty->driver_data;
375         int r;
376         uint16_t reg_contents;
377         uint8_t *break_reg;
378 
379         break_reg = kmalloc(2, GFP_KERNEL);
380         if (!break_reg)
381                 return;
382 
383         r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
384                         ch341_break_reg, 0, break_reg, 2);
385         if (r < 0) {
386                 dev_err(&port->dev, "%s - USB control read error (%d)\n",
387                                 __func__, r);
388                 goto out;
389         }
390         dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
391                 __func__, break_reg[0], break_reg[1]);
392         if (break_state != 0) {
393                 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
394                 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
395                 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
396         } else {
397                 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
398                 break_reg[0] |= CH341_NBREAK_BITS_REG1;
399                 break_reg[1] |= CH341_NBREAK_BITS_REG2;
400         }
401         dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
402                 __func__, break_reg[0], break_reg[1]);
403         reg_contents = get_unaligned_le16(break_reg);
404         r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
405                         ch341_break_reg, reg_contents);
406         if (r < 0)
407                 dev_err(&port->dev, "%s - USB control write error (%d)\n",
408                                 __func__, r);
409 out:
410         kfree(break_reg);
411 }
412 
413 static int ch341_tiocmset(struct tty_struct *tty,
414                           unsigned int set, unsigned int clear)
415 {
416         struct usb_serial_port *port = tty->driver_data;
417         struct ch341_private *priv = usb_get_serial_port_data(port);
418         unsigned long flags;
419         u8 control;
420 
421         spin_lock_irqsave(&priv->lock, flags);
422         if (set & TIOCM_RTS)
423                 priv->line_control |= CH341_BIT_RTS;
424         if (set & TIOCM_DTR)
425                 priv->line_control |= CH341_BIT_DTR;
426         if (clear & TIOCM_RTS)
427                 priv->line_control &= ~CH341_BIT_RTS;
428         if (clear & TIOCM_DTR)
429                 priv->line_control &= ~CH341_BIT_DTR;
430         control = priv->line_control;
431         spin_unlock_irqrestore(&priv->lock, flags);
432 
433         return ch341_set_handshake(port->serial->dev, control);
434 }
435 
436 static void ch341_update_line_status(struct usb_serial_port *port,
437                                         unsigned char *data, size_t len)
438 {
439         struct ch341_private *priv = usb_get_serial_port_data(port);
440         struct tty_struct *tty;
441         unsigned long flags;
442         u8 status;
443         u8 delta;
444 
445         if (len < 4)
446                 return;
447 
448         status = ~data[2] & CH341_BITS_MODEM_STAT;
449 
450         spin_lock_irqsave(&priv->lock, flags);
451         delta = status ^ priv->line_status;
452         priv->line_status = status;
453         spin_unlock_irqrestore(&priv->lock, flags);
454 
455         if (data[1] & CH341_MULT_STAT)
456                 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
457 
458         if (!delta)
459                 return;
460 
461         if (delta & CH341_BIT_CTS)
462                 port->icount.cts++;
463         if (delta & CH341_BIT_DSR)
464                 port->icount.dsr++;
465         if (delta & CH341_BIT_RI)
466                 port->icount.rng++;
467         if (delta & CH341_BIT_DCD) {
468                 port->icount.dcd++;
469                 tty = tty_port_tty_get(&port->port);
470                 if (tty) {
471                         usb_serial_handle_dcd_change(port, tty,
472                                                 status & CH341_BIT_DCD);
473                         tty_kref_put(tty);
474                 }
475         }
476 
477         wake_up_interruptible(&port->port.delta_msr_wait);
478 }
479 
480 static void ch341_read_int_callback(struct urb *urb)
481 {
482         struct usb_serial_port *port = urb->context;
483         unsigned char *data = urb->transfer_buffer;
484         unsigned int len = urb->actual_length;
485         int status;
486 
487         switch (urb->status) {
488         case 0:
489                 /* success */
490                 break;
491         case -ECONNRESET:
492         case -ENOENT:
493         case -ESHUTDOWN:
494                 /* this urb is terminated, clean up */
495                 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
496                         __func__, urb->status);
497                 return;
498         default:
499                 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
500                         __func__, urb->status);
501                 goto exit;
502         }
503 
504         usb_serial_debug_data(&port->dev, __func__, len, data);
505         ch341_update_line_status(port, data, len);
506 exit:
507         status = usb_submit_urb(urb, GFP_ATOMIC);
508         if (status) {
509                 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
510                         __func__, status);
511         }
512 }
513 
514 static int ch341_tiocmget(struct tty_struct *tty)
515 {
516         struct usb_serial_port *port = tty->driver_data;
517         struct ch341_private *priv = usb_get_serial_port_data(port);
518         unsigned long flags;
519         u8 mcr;
520         u8 status;
521         unsigned int result;
522 
523         spin_lock_irqsave(&priv->lock, flags);
524         mcr = priv->line_control;
525         status = priv->line_status;
526         spin_unlock_irqrestore(&priv->lock, flags);
527 
528         result = ((mcr & CH341_BIT_DTR)         ? TIOCM_DTR : 0)
529                   | ((mcr & CH341_BIT_RTS)      ? TIOCM_RTS : 0)
530                   | ((status & CH341_BIT_CTS)   ? TIOCM_CTS : 0)
531                   | ((status & CH341_BIT_DSR)   ? TIOCM_DSR : 0)
532                   | ((status & CH341_BIT_RI)    ? TIOCM_RI  : 0)
533                   | ((status & CH341_BIT_DCD)   ? TIOCM_CD  : 0);
534 
535         dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
536 
537         return result;
538 }
539 
540 static int ch341_reset_resume(struct usb_serial *serial)
541 {
542         struct ch341_private *priv;
543 
544         priv = usb_get_serial_port_data(serial->port[0]);
545 
546         /* reconfigure ch341 serial port after bus-reset */
547         ch341_configure(serial->dev, priv);
548 
549         return 0;
550 }
551 
552 static struct usb_serial_driver ch341_device = {
553         .driver = {
554                 .owner  = THIS_MODULE,
555                 .name   = "ch341-uart",
556         },
557         .id_table          = id_table,
558         .num_ports         = 1,
559         .open              = ch341_open,
560         .dtr_rts           = ch341_dtr_rts,
561         .carrier_raised    = ch341_carrier_raised,
562         .close             = ch341_close,
563         .set_termios       = ch341_set_termios,
564         .break_ctl         = ch341_break_ctl,
565         .tiocmget          = ch341_tiocmget,
566         .tiocmset          = ch341_tiocmset,
567         .tiocmiwait        = usb_serial_generic_tiocmiwait,
568         .read_int_callback = ch341_read_int_callback,
569         .port_probe        = ch341_port_probe,
570         .port_remove       = ch341_port_remove,
571         .reset_resume      = ch341_reset_resume,
572 };
573 
574 static struct usb_serial_driver * const serial_drivers[] = {
575         &ch341_device, NULL
576 };
577 
578 module_usb_serial_driver(serial_drivers, id_table);
579 
580 MODULE_LICENSE("GPL");
581 

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