1 /*****************************************************************************/
4 * baycom_ser_hdx.c -- baycom ser12 halfduplex radio modem driver.
6 * Copyright (C) 1996-2000 Thomas Sailer (sailer@ife.ee.ethz.ch)
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 * Please note that the GPL allows you to use the driver, NOT the radio.
23 * In order to use the radio, you need a license from the communications
24 * authority of your country.
29 * ser12: This is a very simple 1200 baud AFSK modem. The modem consists only
30 * of a modulator/demodulator chip, usually a TI TCM3105. The computer
31 * is responsible for regenerating the receiver bit clock, as well as
32 * for handling the HDLC protocol. The modem connects to a serial port,
33 * hence the name. Since the serial port is not used as an async serial
34 * port, the kernel driver for serial ports cannot be used, and this
35 * driver only supports standard serial hardware (8250, 16450, 16550A)
38 * Command line options (insmod command line)
40 * mode ser12 hardware DCD
42 * ser12@ hardware/software DCD, i.e. no explicit DCD signal but hardware
43 * mutes audio input to the modem
44 * ser12+ hardware DCD, inverted signal at DCD pin
45 * iobase base address of the port; common values are 0x3f8, 0x2f8, 0x3e8, 0x2e8
46 * irq interrupt line of the port; common values are 4,3
50 * 0.1 26.06.1996 Adapted from baycom.c and made network driver interface
51 * 18.10.1996 Changed to new user space access routines (copy_{to,from}_user)
52 * 0.3 26.04.1997 init code/data tagged
53 * 0.4 08.07.1997 alternative ser12 decoding algorithm (uses delta CTS ints)
54 * 0.5 11.11.1997 ser12/par96 split into separate files
55 * 0.6 14.04.1998 cleanups
56 * 0.7 03.08.1999 adapt to Linus' new __setup/__initcall
57 * 0.8 10.08.1999 use module_init/module_exit
58 * 0.9 12.02.2000 adapted to softnet driver interface
59 * 0.10 03.07.2000 fix interface name handling
62 /*****************************************************************************/
64 #include <linux/module.h>
65 #include <linux/ioport.h>
66 #include <linux/string.h>
67 #include <linux/init.h>
68 #include <asm/uaccess.h>
70 #include <linux/hdlcdrv.h>
71 #include <linux/baycom.h>
73 /* --------------------------------------------------------------------- */
77 /* --------------------------------------------------------------------- */
79 static const char bc_drvname
[] = "baycom_ser_hdx";
80 static const char bc_drvinfo
[] = KERN_INFO
"baycom_ser_hdx: (C) 1996-2000 Thomas Sailer, HB9JNX/AE4WA\n"
81 KERN_INFO
"baycom_ser_hdx: version 0.10 compiled " __TIME__
" " __DATE__
"\n";
83 /* --------------------------------------------------------------------- */
87 static struct net_device
*baycom_device
[NR_PORTS
];
89 /* --------------------------------------------------------------------- */
91 #define RBR(iobase) (iobase+0)
92 #define THR(iobase) (iobase+0)
93 #define IER(iobase) (iobase+1)
94 #define IIR(iobase) (iobase+2)
95 #define FCR(iobase) (iobase+2)
96 #define LCR(iobase) (iobase+3)
97 #define MCR(iobase) (iobase+4)
98 #define LSR(iobase) (iobase+5)
99 #define MSR(iobase) (iobase+6)
100 #define SCR(iobase) (iobase+7)
101 #define DLL(iobase) (iobase+0)
102 #define DLM(iobase) (iobase+1)
104 #define SER12_EXTENT 8
106 /* ---------------------------------------------------------------------- */
108 * Information that need to be kept for each board.
111 struct baycom_state
{
112 struct hdlcdrv_state hdrv
;
120 struct modem_state_ser12
{
121 unsigned char tx_bit
;
122 int dcd_sum0
, dcd_sum1
, dcd_sum2
;
123 unsigned char last_sample
;
124 unsigned char last_rxbit
;
125 unsigned int dcd_shreg
;
126 unsigned int dcd_time
;
127 unsigned int bit_pll
;
128 unsigned char interm_sample
;
134 unsigned long last_jiffies
;
136 unsigned last_intcnt
;
140 #endif /* BAYCOM_DEBUG */
143 /* --------------------------------------------------------------------- */
145 static inline void baycom_int_freq(struct baycom_state
*bc
)
148 unsigned long cur_jiffies
= jiffies
;
150 * measure the interrupt frequency
152 bc
->debug_vals
.cur_intcnt
++;
153 if ((cur_jiffies
- bc
->debug_vals
.last_jiffies
) >= HZ
) {
154 bc
->debug_vals
.last_jiffies
= cur_jiffies
;
155 bc
->debug_vals
.last_intcnt
= bc
->debug_vals
.cur_intcnt
;
156 bc
->debug_vals
.cur_intcnt
= 0;
157 bc
->debug_vals
.last_pllcorr
= bc
->debug_vals
.cur_pllcorr
;
158 bc
->debug_vals
.cur_pllcorr
= 0;
160 #endif /* BAYCOM_DEBUG */
163 /* --------------------------------------------------------------------- */
165 * ===================== SER12 specific routines =========================
168 static inline void ser12_set_divisor(struct net_device
*dev
,
169 unsigned char divisor
)
171 outb(0x81, LCR(dev
->base_addr
)); /* DLAB = 1 */
172 outb(divisor
, DLL(dev
->base_addr
));
173 outb(0, DLM(dev
->base_addr
));
174 outb(0x01, LCR(dev
->base_addr
)); /* word length = 6 */
176 * make sure the next interrupt is generated;
177 * 0 must be used to power the modem; the modem draws its
178 * power from the TxD line
180 outb(0x00, THR(dev
->base_addr
));
182 * it is important not to set the divider while transmitting;
183 * this reportedly makes some UARTs generating interrupts
184 * in the hundredthousands per second region
185 * Reported by: Ignacio.Arenaza@studi.epfl.ch (Ignacio Arenaza Nuno)
189 /* --------------------------------------------------------------------- */
192 * must call the TX arbitrator every 10ms
194 #define SER12_ARB_DIVIDER(bc) (bc->opt_dcd ? 24 : 36)
196 #define SER12_DCD_INTERVAL(bc) (bc->opt_dcd ? 12 : 240)
198 static inline void ser12_tx(struct net_device
*dev
, struct baycom_state
*bc
)
200 /* one interrupt per channel bit */
201 ser12_set_divisor(dev
, 12);
203 * first output the last bit (!) then call HDLC transmitter,
204 * since this may take quite long
206 outb(0x0e | (!!bc
->modem
.ser12
.tx_bit
), MCR(dev
->base_addr
));
207 if (bc
->modem
.shreg
<= 1)
208 bc
->modem
.shreg
= 0x10000 | hdlcdrv_getbits(&bc
->hdrv
);
209 bc
->modem
.ser12
.tx_bit
= !(bc
->modem
.ser12
.tx_bit
^
210 (bc
->modem
.shreg
& 1));
211 bc
->modem
.shreg
>>= 1;
214 /* --------------------------------------------------------------------- */
216 static inline void ser12_rx(struct net_device
*dev
, struct baycom_state
*bc
)
222 cur_s
= inb(MSR(dev
->base_addr
)) & 0x10; /* the CTS line */
223 hdlcdrv_channelbit(&bc
->hdrv
, cur_s
);
224 bc
->modem
.ser12
.dcd_shreg
= (bc
->modem
.ser12
.dcd_shreg
<< 1) |
225 (cur_s
!= bc
->modem
.ser12
.last_sample
);
226 bc
->modem
.ser12
.last_sample
= cur_s
;
227 if(bc
->modem
.ser12
.dcd_shreg
& 1) {
229 unsigned int dcdspos
, dcdsneg
;
231 dcdspos
= dcdsneg
= 0;
232 dcdspos
+= ((bc
->modem
.ser12
.dcd_shreg
>> 1) & 1);
233 if (!(bc
->modem
.ser12
.dcd_shreg
& 0x7ffffffe))
235 dcdsneg
+= ((bc
->modem
.ser12
.dcd_shreg
>> 2) & 1);
236 dcdsneg
+= ((bc
->modem
.ser12
.dcd_shreg
>> 3) & 1);
237 dcdsneg
+= ((bc
->modem
.ser12
.dcd_shreg
>> 4) & 1);
239 bc
->modem
.ser12
.dcd_sum0
+= 16*dcdspos
- dcdsneg
;
241 bc
->modem
.ser12
.dcd_sum0
--;
243 if(!bc
->modem
.ser12
.dcd_time
) {
244 hdlcdrv_setdcd(&bc
->hdrv
, (bc
->modem
.ser12
.dcd_sum0
+
245 bc
->modem
.ser12
.dcd_sum1
+
246 bc
->modem
.ser12
.dcd_sum2
) < 0);
247 bc
->modem
.ser12
.dcd_sum2
= bc
->modem
.ser12
.dcd_sum1
;
248 bc
->modem
.ser12
.dcd_sum1
= bc
->modem
.ser12
.dcd_sum0
;
249 /* offset to ensure DCD off on silent input */
250 bc
->modem
.ser12
.dcd_sum0
= 2;
251 bc
->modem
.ser12
.dcd_time
= SER12_DCD_INTERVAL(bc
);
253 bc
->modem
.ser12
.dcd_time
--;
256 * PLL code for the improved software DCD algorithm
258 if (bc
->modem
.ser12
.interm_sample
) {
260 * intermediate sample; set timing correction to normal
262 ser12_set_divisor(dev
, 4);
265 * do PLL correction and call HDLC receiver
267 switch (bc
->modem
.ser12
.dcd_shreg
& 7) {
268 case 1: /* transition too late */
269 ser12_set_divisor(dev
, 5);
271 bc
->debug_vals
.cur_pllcorr
++;
272 #endif /* BAYCOM_DEBUG */
274 case 4: /* transition too early */
275 ser12_set_divisor(dev
, 3);
277 bc
->debug_vals
.cur_pllcorr
--;
278 #endif /* BAYCOM_DEBUG */
281 ser12_set_divisor(dev
, 4);
284 bc
->modem
.shreg
>>= 1;
285 if (bc
->modem
.ser12
.last_sample
==
286 bc
->modem
.ser12
.last_rxbit
)
287 bc
->modem
.shreg
|= 0x10000;
288 bc
->modem
.ser12
.last_rxbit
=
289 bc
->modem
.ser12
.last_sample
;
291 if (++bc
->modem
.ser12
.interm_sample
>= 3)
292 bc
->modem
.ser12
.interm_sample
= 0;
296 if (bc
->modem
.ser12
.dcd_shreg
& 1) {
297 unsigned int dcdspos
, dcdsneg
;
299 dcdspos
= dcdsneg
= 0;
300 dcdspos
+= ((bc
->modem
.ser12
.dcd_shreg
>> 1) & 1);
301 dcdspos
+= (!(bc
->modem
.ser12
.dcd_shreg
& 0x7ffffffe))
303 dcdsneg
+= ((bc
->modem
.ser12
.dcd_shreg
>> 2) & 1);
304 dcdsneg
+= ((bc
->modem
.ser12
.dcd_shreg
>> 3) & 1);
305 dcdsneg
+= ((bc
->modem
.ser12
.dcd_shreg
>> 4) & 1);
307 bc
->modem
.ser12
.dcd_sum0
+= 16*dcdspos
- dcdsneg
;
311 * PLL algorithm for the hardware squelch DCD algorithm
313 if (bc
->modem
.ser12
.interm_sample
) {
315 * intermediate sample; set timing correction to normal
317 ser12_set_divisor(dev
, 6);
320 * do PLL correction and call HDLC receiver
322 switch (bc
->modem
.ser12
.dcd_shreg
& 3) {
323 case 1: /* transition too late */
324 ser12_set_divisor(dev
, 7);
326 bc
->debug_vals
.cur_pllcorr
++;
327 #endif /* BAYCOM_DEBUG */
329 case 2: /* transition too early */
330 ser12_set_divisor(dev
, 5);
332 bc
->debug_vals
.cur_pllcorr
--;
333 #endif /* BAYCOM_DEBUG */
336 ser12_set_divisor(dev
, 6);
339 bc
->modem
.shreg
>>= 1;
340 if (bc
->modem
.ser12
.last_sample
==
341 bc
->modem
.ser12
.last_rxbit
)
342 bc
->modem
.shreg
|= 0x10000;
343 bc
->modem
.ser12
.last_rxbit
=
344 bc
->modem
.ser12
.last_sample
;
346 bc
->modem
.ser12
.interm_sample
= !bc
->modem
.ser12
.interm_sample
;
350 bc
->modem
.ser12
.dcd_sum0
-= (bc
->modem
.ser12
.dcd_shreg
& 1);
352 outb(0x0d, MCR(dev
->base_addr
)); /* transmitter off */
353 if (bc
->modem
.shreg
& 1) {
354 hdlcdrv_putbits(&bc
->hdrv
, bc
->modem
.shreg
>> 1);
355 bc
->modem
.shreg
= 0x10000;
357 if(!bc
->modem
.ser12
.dcd_time
) {
359 hdlcdrv_setdcd(&bc
->hdrv
, !((inb(MSR(dev
->base_addr
)) ^ bc
->opt_dcd
) & 0x80));
361 hdlcdrv_setdcd(&bc
->hdrv
, (bc
->modem
.ser12
.dcd_sum0
+
362 bc
->modem
.ser12
.dcd_sum1
+
363 bc
->modem
.ser12
.dcd_sum2
) < 0);
364 bc
->modem
.ser12
.dcd_sum2
= bc
->modem
.ser12
.dcd_sum1
;
365 bc
->modem
.ser12
.dcd_sum1
= bc
->modem
.ser12
.dcd_sum0
;
366 /* offset to ensure DCD off on silent input */
367 bc
->modem
.ser12
.dcd_sum0
= 2;
368 bc
->modem
.ser12
.dcd_time
= SER12_DCD_INTERVAL(bc
);
370 bc
->modem
.ser12
.dcd_time
--;
373 /* --------------------------------------------------------------------- */
375 static irqreturn_t
ser12_interrupt(int irq
, void *dev_id
, struct pt_regs
*regs
)
377 struct net_device
*dev
= (struct net_device
*)dev_id
;
378 struct baycom_state
*bc
= netdev_priv(dev
);
381 if (!dev
|| !bc
|| bc
->hdrv
.magic
!= HDLCDRV_MAGIC
)
384 if ((iir
= inb(IIR(dev
->base_addr
))) & 1)
390 inb(LSR(dev
->base_addr
));
394 inb(RBR(dev
->base_addr
));
399 * check if transmitter active
401 if (hdlcdrv_ptt(&bc
->hdrv
))
405 bc
->modem
.arb_divider
--;
407 outb(0x00, THR(dev
->base_addr
));
411 inb(MSR(dev
->base_addr
));
414 iir
= inb(IIR(dev
->base_addr
));
415 } while (!(iir
& 1));
416 if (bc
->modem
.arb_divider
<= 0) {
417 bc
->modem
.arb_divider
= SER12_ARB_DIVIDER(bc
);
419 hdlcdrv_arbitrate(dev
, &bc
->hdrv
);
422 hdlcdrv_transmitter(dev
, &bc
->hdrv
);
423 hdlcdrv_receiver(dev
, &bc
->hdrv
);
428 /* --------------------------------------------------------------------- */
430 enum uart
{ c_uart_unknown
, c_uart_8250
,
431 c_uart_16450
, c_uart_16550
, c_uart_16550A
};
432 static const char *uart_str
[] = {
433 "unknown", "8250", "16450", "16550", "16550A"
436 static enum uart
ser12_check_uart(unsigned int iobase
)
438 unsigned char b1
,b2
,b3
;
440 enum uart uart_tab
[] =
441 { c_uart_16450
, c_uart_unknown
, c_uart_16550
, c_uart_16550A
};
443 b1
= inb(MCR(iobase
));
444 outb(b1
| 0x10, MCR(iobase
)); /* loopback mode */
445 b2
= inb(MSR(iobase
));
446 outb(0x1a, MCR(iobase
));
447 b3
= inb(MSR(iobase
)) & 0xf0;
448 outb(b1
, MCR(iobase
)); /* restore old values */
449 outb(b2
, MSR(iobase
));
451 return c_uart_unknown
;
454 outb(0x01, FCR(iobase
)); /* enable FIFOs */
455 u
= uart_tab
[(inb(IIR(iobase
)) >> 6) & 3];
456 if (u
== c_uart_16450
) {
457 outb(0x5a, SCR(iobase
));
458 b1
= inb(SCR(iobase
));
459 outb(0xa5, SCR(iobase
));
460 b2
= inb(SCR(iobase
));
461 if ((b1
!= 0x5a) || (b2
!= 0xa5))
467 /* --------------------------------------------------------------------- */
469 static int ser12_open(struct net_device
*dev
)
471 struct baycom_state
*bc
= netdev_priv(dev
);
476 if (!dev
->base_addr
|| dev
->base_addr
> 0x1000-SER12_EXTENT
||
477 dev
->irq
< 2 || dev
->irq
> 15)
479 if (!request_region(dev
->base_addr
, SER12_EXTENT
, "baycom_ser12"))
481 memset(&bc
->modem
, 0, sizeof(bc
->modem
));
482 bc
->hdrv
.par
.bitrate
= 1200;
483 if ((u
= ser12_check_uart(dev
->base_addr
)) == c_uart_unknown
) {
484 release_region(dev
->base_addr
, SER12_EXTENT
);
487 outb(0, FCR(dev
->base_addr
)); /* disable FIFOs */
488 outb(0x0d, MCR(dev
->base_addr
));
489 outb(0, IER(dev
->base_addr
));
490 if (request_irq(dev
->irq
, ser12_interrupt
, SA_INTERRUPT
| SA_SHIRQ
,
491 "baycom_ser12", dev
)) {
492 release_region(dev
->base_addr
, SER12_EXTENT
);
496 * enable transmitter empty interrupt
498 outb(2, IER(dev
->base_addr
));
500 * set the SIO to 6 Bits/character and 19200 or 28800 baud, so that
501 * we get exactly (hopefully) 2 or 3 interrupts per radio symbol,
502 * depending on the usage of the software DCD routine
504 ser12_set_divisor(dev
, bc
->opt_dcd
? 6 : 4);
505 printk(KERN_INFO
"%s: ser12 at iobase 0x%lx irq %u uart %s\n",
506 bc_drvname
, dev
->base_addr
, dev
->irq
, uart_str
[u
]);
510 /* --------------------------------------------------------------------- */
512 static int ser12_close(struct net_device
*dev
)
514 struct baycom_state
*bc
= netdev_priv(dev
);
521 outb(0, IER(dev
->base_addr
));
522 outb(1, MCR(dev
->base_addr
));
523 free_irq(dev
->irq
, dev
);
524 release_region(dev
->base_addr
, SER12_EXTENT
);
525 printk(KERN_INFO
"%s: close ser12 at iobase 0x%lx irq %u\n",
526 bc_drvname
, dev
->base_addr
, dev
->irq
);
530 /* --------------------------------------------------------------------- */
532 * ===================== hdlcdrv driver interface =========================
535 /* --------------------------------------------------------------------- */
537 static int baycom_ioctl(struct net_device
*dev
, struct ifreq
*ifr
,
538 struct hdlcdrv_ioctl
*hi
, int cmd
);
540 /* --------------------------------------------------------------------- */
542 static struct hdlcdrv_ops ser12_ops
= {
543 .drvname
= bc_drvname
,
544 .drvinfo
= bc_drvinfo
,
546 .close
= ser12_close
,
547 .ioctl
= baycom_ioctl
,
550 /* --------------------------------------------------------------------- */
552 static int baycom_setmode(struct baycom_state
*bc
, const char *modestr
)
554 if (strchr(modestr
, '*'))
556 else if (strchr(modestr
, '+'))
558 else if (strchr(modestr
, '@'))
565 /* --------------------------------------------------------------------- */
567 static int baycom_ioctl(struct net_device
*dev
, struct ifreq
*ifr
,
568 struct hdlcdrv_ioctl
*hi
, int cmd
)
570 struct baycom_state
*bc
;
571 struct baycom_ioctl bi
;
576 bc
= netdev_priv(dev
);
577 BUG_ON(bc
->hdrv
.magic
!= HDLCDRV_MAGIC
);
579 if (cmd
!= SIOCDEVPRIVATE
)
585 case HDLCDRVCTL_GETMODE
:
586 strcpy(hi
->data
.modename
, "ser12");
587 if (bc
->opt_dcd
<= 0)
588 strcat(hi
->data
.modename
, (!bc
->opt_dcd
) ? "*" : (bc
->opt_dcd
== -2) ? "@" : "+");
589 if (copy_to_user(ifr
->ifr_data
, hi
, sizeof(struct hdlcdrv_ioctl
)))
593 case HDLCDRVCTL_SETMODE
:
594 if (netif_running(dev
) || !capable(CAP_NET_ADMIN
))
596 hi
->data
.modename
[sizeof(hi
->data
.modename
)-1] = '\0';
597 return baycom_setmode(bc
, hi
->data
.modename
);
599 case HDLCDRVCTL_MODELIST
:
600 strcpy(hi
->data
.modename
, "ser12");
601 if (copy_to_user(ifr
->ifr_data
, hi
, sizeof(struct hdlcdrv_ioctl
)))
605 case HDLCDRVCTL_MODEMPARMASK
:
606 return HDLCDRV_PARMASK_IOBASE
| HDLCDRV_PARMASK_IRQ
;
610 if (copy_from_user(&bi
, ifr
->ifr_data
, sizeof(bi
)))
617 case BAYCOMCTL_GETDEBUG
:
618 bi
.data
.dbg
.debug1
= bc
->hdrv
.ptt_keyed
;
619 bi
.data
.dbg
.debug2
= bc
->debug_vals
.last_intcnt
;
620 bi
.data
.dbg
.debug3
= bc
->debug_vals
.last_pllcorr
;
622 #endif /* BAYCOM_DEBUG */
625 if (copy_to_user(ifr
->ifr_data
, &bi
, sizeof(bi
)))
631 /* --------------------------------------------------------------------- */
634 * command line settable parameters
636 static char *mode
[NR_PORTS
] = { "ser12*", };
637 static int iobase
[NR_PORTS
] = { 0x3f8, };
638 static int irq
[NR_PORTS
] = { 4, };
640 module_param_array(mode
, charp
, NULL
, 0);
641 MODULE_PARM_DESC(mode
, "baycom operating mode; * for software DCD");
642 module_param_array(iobase
, int, NULL
, 0);
643 MODULE_PARM_DESC(iobase
, "baycom io base address");
644 module_param_array(irq
, int, NULL
, 0);
645 MODULE_PARM_DESC(irq
, "baycom irq number");
647 MODULE_AUTHOR("Thomas M. Sailer, sailer@ife.ee.ethz.ch, hb9jnx@hb9w.che.eu");
648 MODULE_DESCRIPTION("Baycom ser12 half duplex amateur radio modem driver");
649 MODULE_LICENSE("GPL");
651 /* --------------------------------------------------------------------- */
653 static int __init
init_baycomserhdx(void)
660 * register net devices
662 for (i
= 0; i
< NR_PORTS
; i
++) {
663 struct net_device
*dev
;
664 struct baycom_state
*bc
;
665 char ifname
[IFNAMSIZ
];
667 sprintf(ifname
, "bcsh%d", i
);
672 iobase
[i
] = irq
[i
] = 0;
674 dev
= hdlcdrv_register(&ser12_ops
,
675 sizeof(struct baycom_state
),
676 ifname
, iobase
[i
], irq
[i
], 0);
680 bc
= netdev_priv(dev
);
681 if (set_hw
&& baycom_setmode(bc
, mode
[i
]))
684 baycom_device
[i
] = dev
;
692 static void __exit
cleanup_baycomserhdx(void)
696 for(i
= 0; i
< NR_PORTS
; i
++) {
697 struct net_device
*dev
= baycom_device
[i
];
700 hdlcdrv_unregister(dev
);
704 module_init(init_baycomserhdx
);
705 module_exit(cleanup_baycomserhdx
);
707 /* --------------------------------------------------------------------- */
712 * format: baycom_ser_hdx=io,irq,mode
713 * mode: ser12 hardware DCD
714 * ser12* software DCD
715 * ser12@ hardware/software DCD, i.e. no explicit DCD signal but hardware
716 * mutes audio input to the modem
717 * ser12+ hardware DCD, inverted signal at DCD pin
720 static int __init
baycom_ser_hdx_setup(char *str
)
722 static unsigned nr_dev
;
725 if (nr_dev
>= NR_PORTS
)
727 str
= get_options(str
, 3, ints
);
731 iobase
[nr_dev
] = ints
[1];
732 irq
[nr_dev
] = ints
[2];
737 __setup("baycom_ser_hdx=", baycom_ser_hdx_setup
);
740 /* --------------------------------------------------------------------- */