xref: /openbmc/linux/drivers/tty/serial/max3100.c (revision 4f3db074)
1 /*
2  *
3  *  Copyright (C) 2008 Christian Pellegrin <chripell@evolware.org>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  *
11  * Notes: the MAX3100 doesn't provide an interrupt on CTS so we have
12  * to use polling for flow control. TX empty IRQ is unusable, since
13  * writing conf clears FIFO buffer and we cannot have this interrupt
14  * always asking us for attention.
15  *
16  * Example platform data:
17 
18  static struct plat_max3100 max3100_plat_data = {
19  .loopback = 0,
20  .crystal = 0,
21  .poll_time = 100,
22  };
23 
24  static struct spi_board_info spi_board_info[] = {
25  {
26  .modalias	= "max3100",
27  .platform_data	= &max3100_plat_data,
28  .irq		= IRQ_EINT12,
29  .max_speed_hz	= 5*1000*1000,
30  .chip_select	= 0,
31  },
32  };
33 
34  * The initial minor number is 209 in the low-density serial port:
35  * mknod /dev/ttyMAX0 c 204 209
36  */
37 
38 #define MAX3100_MAJOR 204
39 #define MAX3100_MINOR 209
40 /* 4 MAX3100s should be enough for everyone */
41 #define MAX_MAX3100 4
42 
43 #include <linux/delay.h>
44 #include <linux/slab.h>
45 #include <linux/device.h>
46 #include <linux/module.h>
47 #include <linux/serial_core.h>
48 #include <linux/serial.h>
49 #include <linux/spi/spi.h>
50 #include <linux/freezer.h>
51 #include <linux/tty.h>
52 #include <linux/tty_flip.h>
53 
54 #include <linux/serial_max3100.h>
55 
56 #define MAX3100_C    (1<<14)
57 #define MAX3100_D    (0<<14)
58 #define MAX3100_W    (1<<15)
59 #define MAX3100_RX   (0<<15)
60 
61 #define MAX3100_WC   (MAX3100_W  | MAX3100_C)
62 #define MAX3100_RC   (MAX3100_RX | MAX3100_C)
63 #define MAX3100_WD   (MAX3100_W  | MAX3100_D)
64 #define MAX3100_RD   (MAX3100_RX | MAX3100_D)
65 #define MAX3100_CMD  (3 << 14)
66 
67 #define MAX3100_T    (1<<14)
68 #define MAX3100_R    (1<<15)
69 
70 #define MAX3100_FEN  (1<<13)
71 #define MAX3100_SHDN (1<<12)
72 #define MAX3100_TM   (1<<11)
73 #define MAX3100_RM   (1<<10)
74 #define MAX3100_PM   (1<<9)
75 #define MAX3100_RAM  (1<<8)
76 #define MAX3100_IR   (1<<7)
77 #define MAX3100_ST   (1<<6)
78 #define MAX3100_PE   (1<<5)
79 #define MAX3100_L    (1<<4)
80 #define MAX3100_BAUD (0xf)
81 
82 #define MAX3100_TE   (1<<10)
83 #define MAX3100_RAFE (1<<10)
84 #define MAX3100_RTS  (1<<9)
85 #define MAX3100_CTS  (1<<9)
86 #define MAX3100_PT   (1<<8)
87 #define MAX3100_DATA (0xff)
88 
89 #define MAX3100_RT   (MAX3100_R | MAX3100_T)
90 #define MAX3100_RTC  (MAX3100_RT | MAX3100_CTS | MAX3100_RAFE)
91 
92 /* the following simulate a status reg for ignore_status_mask */
93 #define MAX3100_STATUS_PE 1
94 #define MAX3100_STATUS_FE 2
95 #define MAX3100_STATUS_OE 4
96 
97 struct max3100_port {
98 	struct uart_port port;
99 	struct spi_device *spi;
100 
101 	int cts;	        /* last CTS received for flow ctrl */
102 	int tx_empty;		/* last TX empty bit */
103 
104 	spinlock_t conf_lock;	/* shared data */
105 	int conf_commit;	/* need to make changes */
106 	int conf;		/* configuration for the MAX31000
107 				 * (bits 0-7, bits 8-11 are irqs) */
108 	int rts_commit;	        /* need to change rts */
109 	int rts;		/* rts status */
110 	int baud;		/* current baud rate */
111 
112 	int parity;		/* keeps track if we should send parity */
113 #define MAX3100_PARITY_ON 1
114 #define MAX3100_PARITY_ODD 2
115 #define MAX3100_7BIT 4
116 	int rx_enabled;	        /* if we should rx chars */
117 
118 	int irq;		/* irq assigned to the max3100 */
119 
120 	int minor;		/* minor number */
121 	int crystal;		/* 1 if 3.6864Mhz crystal 0 for 1.8432 */
122 	int loopback;		/* 1 if we are in loopback mode */
123 
124 	/* for handling irqs: need workqueue since we do spi_sync */
125 	struct workqueue_struct *workqueue;
126 	struct work_struct work;
127 	/* set to 1 to make the workhandler exit as soon as possible */
128 	int  force_end_work;
129 	/* need to know we are suspending to avoid deadlock on workqueue */
130 	int suspending;
131 
132 	/* hook for suspending MAX3100 via dedicated pin */
133 	void (*max3100_hw_suspend) (int suspend);
134 
135 	/* poll time (in ms) for ctrl lines */
136 	int poll_time;
137 	/* and its timer */
138 	struct timer_list	timer;
139 };
140 
141 static struct max3100_port *max3100s[MAX_MAX3100]; /* the chips */
142 static DEFINE_MUTEX(max3100s_lock);		   /* race on probe */
143 
144 static int max3100_do_parity(struct max3100_port *s, u16 c)
145 {
146 	int parity;
147 
148 	if (s->parity & MAX3100_PARITY_ODD)
149 		parity = 1;
150 	else
151 		parity = 0;
152 
153 	if (s->parity & MAX3100_7BIT)
154 		c &= 0x7f;
155 	else
156 		c &= 0xff;
157 
158 	parity = parity ^ (hweight8(c) & 1);
159 	return parity;
160 }
161 
162 static int max3100_check_parity(struct max3100_port *s, u16 c)
163 {
164 	return max3100_do_parity(s, c) == ((c >> 8) & 1);
165 }
166 
167 static void max3100_calc_parity(struct max3100_port *s, u16 *c)
168 {
169 	if (s->parity & MAX3100_7BIT)
170 		*c &= 0x7f;
171 	else
172 		*c &= 0xff;
173 
174 	if (s->parity & MAX3100_PARITY_ON)
175 		*c |= max3100_do_parity(s, *c) << 8;
176 }
177 
178 static void max3100_work(struct work_struct *w);
179 
180 static void max3100_dowork(struct max3100_port *s)
181 {
182 	if (!s->force_end_work && !freezing(current) && !s->suspending)
183 		queue_work(s->workqueue, &s->work);
184 }
185 
186 static void max3100_timeout(unsigned long data)
187 {
188 	struct max3100_port *s = (struct max3100_port *)data;
189 
190 	if (s->port.state) {
191 		max3100_dowork(s);
192 		mod_timer(&s->timer, jiffies + s->poll_time);
193 	}
194 }
195 
196 static int max3100_sr(struct max3100_port *s, u16 tx, u16 *rx)
197 {
198 	struct spi_message message;
199 	u16 etx, erx;
200 	int status;
201 	struct spi_transfer tran = {
202 		.tx_buf = &etx,
203 		.rx_buf = &erx,
204 		.len = 2,
205 	};
206 
207 	etx = cpu_to_be16(tx);
208 	spi_message_init(&message);
209 	spi_message_add_tail(&tran, &message);
210 	status = spi_sync(s->spi, &message);
211 	if (status) {
212 		dev_warn(&s->spi->dev, "error while calling spi_sync\n");
213 		return -EIO;
214 	}
215 	*rx = be16_to_cpu(erx);
216 	s->tx_empty = (*rx & MAX3100_T) > 0;
217 	dev_dbg(&s->spi->dev, "%04x - %04x\n", tx, *rx);
218 	return 0;
219 }
220 
221 static int max3100_handlerx(struct max3100_port *s, u16 rx)
222 {
223 	unsigned int ch, flg, status = 0;
224 	int ret = 0, cts;
225 
226 	if (rx & MAX3100_R && s->rx_enabled) {
227 		dev_dbg(&s->spi->dev, "%s\n", __func__);
228 		ch = rx & (s->parity & MAX3100_7BIT ? 0x7f : 0xff);
229 		if (rx & MAX3100_RAFE) {
230 			s->port.icount.frame++;
231 			flg = TTY_FRAME;
232 			status |= MAX3100_STATUS_FE;
233 		} else {
234 			if (s->parity & MAX3100_PARITY_ON) {
235 				if (max3100_check_parity(s, rx)) {
236 					s->port.icount.rx++;
237 					flg = TTY_NORMAL;
238 				} else {
239 					s->port.icount.parity++;
240 					flg = TTY_PARITY;
241 					status |= MAX3100_STATUS_PE;
242 				}
243 			} else {
244 				s->port.icount.rx++;
245 				flg = TTY_NORMAL;
246 			}
247 		}
248 		uart_insert_char(&s->port, status, MAX3100_STATUS_OE, ch, flg);
249 		ret = 1;
250 	}
251 
252 	cts = (rx & MAX3100_CTS) > 0;
253 	if (s->cts != cts) {
254 		s->cts = cts;
255 		uart_handle_cts_change(&s->port, cts ? TIOCM_CTS : 0);
256 	}
257 
258 	return ret;
259 }
260 
261 static void max3100_work(struct work_struct *w)
262 {
263 	struct max3100_port *s = container_of(w, struct max3100_port, work);
264 	int rxchars;
265 	u16 tx, rx;
266 	int conf, cconf, rts, crts;
267 	struct circ_buf *xmit = &s->port.state->xmit;
268 
269 	dev_dbg(&s->spi->dev, "%s\n", __func__);
270 
271 	rxchars = 0;
272 	do {
273 		spin_lock(&s->conf_lock);
274 		conf = s->conf;
275 		cconf = s->conf_commit;
276 		s->conf_commit = 0;
277 		rts = s->rts;
278 		crts = s->rts_commit;
279 		s->rts_commit = 0;
280 		spin_unlock(&s->conf_lock);
281 		if (cconf)
282 			max3100_sr(s, MAX3100_WC | conf, &rx);
283 		if (crts) {
284 			max3100_sr(s, MAX3100_WD | MAX3100_TE |
285 				   (s->rts ? MAX3100_RTS : 0), &rx);
286 			rxchars += max3100_handlerx(s, rx);
287 		}
288 
289 		max3100_sr(s, MAX3100_RD, &rx);
290 		rxchars += max3100_handlerx(s, rx);
291 
292 		if (rx & MAX3100_T) {
293 			tx = 0xffff;
294 			if (s->port.x_char) {
295 				tx = s->port.x_char;
296 				s->port.icount.tx++;
297 				s->port.x_char = 0;
298 			} else if (!uart_circ_empty(xmit) &&
299 				   !uart_tx_stopped(&s->port)) {
300 				tx = xmit->buf[xmit->tail];
301 				xmit->tail = (xmit->tail + 1) &
302 					(UART_XMIT_SIZE - 1);
303 				s->port.icount.tx++;
304 			}
305 			if (tx != 0xffff) {
306 				max3100_calc_parity(s, &tx);
307 				tx |= MAX3100_WD | (s->rts ? MAX3100_RTS : 0);
308 				max3100_sr(s, tx, &rx);
309 				rxchars += max3100_handlerx(s, rx);
310 			}
311 		}
312 
313 		if (rxchars > 16) {
314 			tty_flip_buffer_push(&s->port.state->port);
315 			rxchars = 0;
316 		}
317 		if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
318 			uart_write_wakeup(&s->port);
319 
320 	} while (!s->force_end_work &&
321 		 !freezing(current) &&
322 		 ((rx & MAX3100_R) ||
323 		  (!uart_circ_empty(xmit) &&
324 		   !uart_tx_stopped(&s->port))));
325 
326 	if (rxchars > 0)
327 		tty_flip_buffer_push(&s->port.state->port);
328 }
329 
330 static irqreturn_t max3100_irq(int irqno, void *dev_id)
331 {
332 	struct max3100_port *s = dev_id;
333 
334 	dev_dbg(&s->spi->dev, "%s\n", __func__);
335 
336 	max3100_dowork(s);
337 	return IRQ_HANDLED;
338 }
339 
340 static void max3100_enable_ms(struct uart_port *port)
341 {
342 	struct max3100_port *s = container_of(port,
343 					      struct max3100_port,
344 					      port);
345 
346 	if (s->poll_time > 0)
347 		mod_timer(&s->timer, jiffies);
348 	dev_dbg(&s->spi->dev, "%s\n", __func__);
349 }
350 
351 static void max3100_start_tx(struct uart_port *port)
352 {
353 	struct max3100_port *s = container_of(port,
354 					      struct max3100_port,
355 					      port);
356 
357 	dev_dbg(&s->spi->dev, "%s\n", __func__);
358 
359 	max3100_dowork(s);
360 }
361 
362 static void max3100_stop_rx(struct uart_port *port)
363 {
364 	struct max3100_port *s = container_of(port,
365 					      struct max3100_port,
366 					      port);
367 
368 	dev_dbg(&s->spi->dev, "%s\n", __func__);
369 
370 	s->rx_enabled = 0;
371 	spin_lock(&s->conf_lock);
372 	s->conf &= ~MAX3100_RM;
373 	s->conf_commit = 1;
374 	spin_unlock(&s->conf_lock);
375 	max3100_dowork(s);
376 }
377 
378 static unsigned int max3100_tx_empty(struct uart_port *port)
379 {
380 	struct max3100_port *s = container_of(port,
381 					      struct max3100_port,
382 					      port);
383 
384 	dev_dbg(&s->spi->dev, "%s\n", __func__);
385 
386 	/* may not be truly up-to-date */
387 	max3100_dowork(s);
388 	return s->tx_empty;
389 }
390 
391 static unsigned int max3100_get_mctrl(struct uart_port *port)
392 {
393 	struct max3100_port *s = container_of(port,
394 					      struct max3100_port,
395 					      port);
396 
397 	dev_dbg(&s->spi->dev, "%s\n", __func__);
398 
399 	/* may not be truly up-to-date */
400 	max3100_dowork(s);
401 	/* always assert DCD and DSR since these lines are not wired */
402 	return (s->cts ? TIOCM_CTS : 0) | TIOCM_DSR | TIOCM_CAR;
403 }
404 
405 static void max3100_set_mctrl(struct uart_port *port, unsigned int mctrl)
406 {
407 	struct max3100_port *s = container_of(port,
408 					      struct max3100_port,
409 					      port);
410 	int rts;
411 
412 	dev_dbg(&s->spi->dev, "%s\n", __func__);
413 
414 	rts = (mctrl & TIOCM_RTS) > 0;
415 
416 	spin_lock(&s->conf_lock);
417 	if (s->rts != rts) {
418 		s->rts = rts;
419 		s->rts_commit = 1;
420 		max3100_dowork(s);
421 	}
422 	spin_unlock(&s->conf_lock);
423 }
424 
425 static void
426 max3100_set_termios(struct uart_port *port, struct ktermios *termios,
427 		    struct ktermios *old)
428 {
429 	struct max3100_port *s = container_of(port,
430 					      struct max3100_port,
431 					      port);
432 	int baud = 0;
433 	unsigned cflag;
434 	u32 param_new, param_mask, parity = 0;
435 
436 	dev_dbg(&s->spi->dev, "%s\n", __func__);
437 
438 	cflag = termios->c_cflag;
439 	param_new = 0;
440 	param_mask = 0;
441 
442 	baud = tty_termios_baud_rate(termios);
443 	param_new = s->conf & MAX3100_BAUD;
444 	switch (baud) {
445 	case 300:
446 		if (s->crystal)
447 			baud = s->baud;
448 		else
449 			param_new = 15;
450 		break;
451 	case 600:
452 		param_new = 14 + s->crystal;
453 		break;
454 	case 1200:
455 		param_new = 13 + s->crystal;
456 		break;
457 	case 2400:
458 		param_new = 12 + s->crystal;
459 		break;
460 	case 4800:
461 		param_new = 11 + s->crystal;
462 		break;
463 	case 9600:
464 		param_new = 10 + s->crystal;
465 		break;
466 	case 19200:
467 		param_new = 9 + s->crystal;
468 		break;
469 	case 38400:
470 		param_new = 8 + s->crystal;
471 		break;
472 	case 57600:
473 		param_new = 1 + s->crystal;
474 		break;
475 	case 115200:
476 		param_new = 0 + s->crystal;
477 		break;
478 	case 230400:
479 		if (s->crystal)
480 			param_new = 0;
481 		else
482 			baud = s->baud;
483 		break;
484 	default:
485 		baud = s->baud;
486 	}
487 	tty_termios_encode_baud_rate(termios, baud, baud);
488 	s->baud = baud;
489 	param_mask |= MAX3100_BAUD;
490 
491 	if ((cflag & CSIZE) == CS8) {
492 		param_new &= ~MAX3100_L;
493 		parity &= ~MAX3100_7BIT;
494 	} else {
495 		param_new |= MAX3100_L;
496 		parity |= MAX3100_7BIT;
497 		cflag = (cflag & ~CSIZE) | CS7;
498 	}
499 	param_mask |= MAX3100_L;
500 
501 	if (cflag & CSTOPB)
502 		param_new |= MAX3100_ST;
503 	else
504 		param_new &= ~MAX3100_ST;
505 	param_mask |= MAX3100_ST;
506 
507 	if (cflag & PARENB) {
508 		param_new |= MAX3100_PE;
509 		parity |= MAX3100_PARITY_ON;
510 	} else {
511 		param_new &= ~MAX3100_PE;
512 		parity &= ~MAX3100_PARITY_ON;
513 	}
514 	param_mask |= MAX3100_PE;
515 
516 	if (cflag & PARODD)
517 		parity |= MAX3100_PARITY_ODD;
518 	else
519 		parity &= ~MAX3100_PARITY_ODD;
520 
521 	/* mask termios capabilities we don't support */
522 	cflag &= ~CMSPAR;
523 	termios->c_cflag = cflag;
524 
525 	s->port.ignore_status_mask = 0;
526 	if (termios->c_iflag & IGNPAR)
527 		s->port.ignore_status_mask |=
528 			MAX3100_STATUS_PE | MAX3100_STATUS_FE |
529 			MAX3100_STATUS_OE;
530 
531 	/* we are sending char from a workqueue so enable */
532 	s->port.state->port.low_latency = 1;
533 
534 	if (s->poll_time > 0)
535 		del_timer_sync(&s->timer);
536 
537 	uart_update_timeout(port, termios->c_cflag, baud);
538 
539 	spin_lock(&s->conf_lock);
540 	s->conf = (s->conf & ~param_mask) | (param_new & param_mask);
541 	s->conf_commit = 1;
542 	s->parity = parity;
543 	spin_unlock(&s->conf_lock);
544 	max3100_dowork(s);
545 
546 	if (UART_ENABLE_MS(&s->port, termios->c_cflag))
547 		max3100_enable_ms(&s->port);
548 }
549 
550 static void max3100_shutdown(struct uart_port *port)
551 {
552 	struct max3100_port *s = container_of(port,
553 					      struct max3100_port,
554 					      port);
555 
556 	dev_dbg(&s->spi->dev, "%s\n", __func__);
557 
558 	if (s->suspending)
559 		return;
560 
561 	s->force_end_work = 1;
562 
563 	if (s->poll_time > 0)
564 		del_timer_sync(&s->timer);
565 
566 	if (s->workqueue) {
567 		flush_workqueue(s->workqueue);
568 		destroy_workqueue(s->workqueue);
569 		s->workqueue = NULL;
570 	}
571 	if (s->irq)
572 		free_irq(s->irq, s);
573 
574 	/* set shutdown mode to save power */
575 	if (s->max3100_hw_suspend)
576 		s->max3100_hw_suspend(1);
577 	else  {
578 		u16 tx, rx;
579 
580 		tx = MAX3100_WC | MAX3100_SHDN;
581 		max3100_sr(s, tx, &rx);
582 	}
583 }
584 
585 static int max3100_startup(struct uart_port *port)
586 {
587 	struct max3100_port *s = container_of(port,
588 					      struct max3100_port,
589 					      port);
590 	char b[12];
591 
592 	dev_dbg(&s->spi->dev, "%s\n", __func__);
593 
594 	s->conf = MAX3100_RM;
595 	s->baud = s->crystal ? 230400 : 115200;
596 	s->rx_enabled = 1;
597 
598 	if (s->suspending)
599 		return 0;
600 
601 	s->force_end_work = 0;
602 	s->parity = 0;
603 	s->rts = 0;
604 
605 	sprintf(b, "max3100-%d", s->minor);
606 	s->workqueue = create_freezable_workqueue(b);
607 	if (!s->workqueue) {
608 		dev_warn(&s->spi->dev, "cannot create workqueue\n");
609 		return -EBUSY;
610 	}
611 	INIT_WORK(&s->work, max3100_work);
612 
613 	if (request_irq(s->irq, max3100_irq,
614 			IRQF_TRIGGER_FALLING, "max3100", s) < 0) {
615 		dev_warn(&s->spi->dev, "cannot allocate irq %d\n", s->irq);
616 		s->irq = 0;
617 		destroy_workqueue(s->workqueue);
618 		s->workqueue = NULL;
619 		return -EBUSY;
620 	}
621 
622 	if (s->loopback) {
623 		u16 tx, rx;
624 		tx = 0x4001;
625 		max3100_sr(s, tx, &rx);
626 	}
627 
628 	if (s->max3100_hw_suspend)
629 		s->max3100_hw_suspend(0);
630 	s->conf_commit = 1;
631 	max3100_dowork(s);
632 	/* wait for clock to settle */
633 	msleep(50);
634 
635 	max3100_enable_ms(&s->port);
636 
637 	return 0;
638 }
639 
640 static const char *max3100_type(struct uart_port *port)
641 {
642 	struct max3100_port *s = container_of(port,
643 					      struct max3100_port,
644 					      port);
645 
646 	dev_dbg(&s->spi->dev, "%s\n", __func__);
647 
648 	return s->port.type == PORT_MAX3100 ? "MAX3100" : NULL;
649 }
650 
651 static void max3100_release_port(struct uart_port *port)
652 {
653 	struct max3100_port *s = container_of(port,
654 					      struct max3100_port,
655 					      port);
656 
657 	dev_dbg(&s->spi->dev, "%s\n", __func__);
658 }
659 
660 static void max3100_config_port(struct uart_port *port, int flags)
661 {
662 	struct max3100_port *s = container_of(port,
663 					      struct max3100_port,
664 					      port);
665 
666 	dev_dbg(&s->spi->dev, "%s\n", __func__);
667 
668 	if (flags & UART_CONFIG_TYPE)
669 		s->port.type = PORT_MAX3100;
670 }
671 
672 static int max3100_verify_port(struct uart_port *port,
673 			       struct serial_struct *ser)
674 {
675 	struct max3100_port *s = container_of(port,
676 					      struct max3100_port,
677 					      port);
678 	int ret = -EINVAL;
679 
680 	dev_dbg(&s->spi->dev, "%s\n", __func__);
681 
682 	if (ser->type == PORT_UNKNOWN || ser->type == PORT_MAX3100)
683 		ret = 0;
684 	return ret;
685 }
686 
687 static void max3100_stop_tx(struct uart_port *port)
688 {
689 	struct max3100_port *s = container_of(port,
690 					      struct max3100_port,
691 					      port);
692 
693 	dev_dbg(&s->spi->dev, "%s\n", __func__);
694 }
695 
696 static int max3100_request_port(struct uart_port *port)
697 {
698 	struct max3100_port *s = container_of(port,
699 					      struct max3100_port,
700 					      port);
701 
702 	dev_dbg(&s->spi->dev, "%s\n", __func__);
703 	return 0;
704 }
705 
706 static void max3100_break_ctl(struct uart_port *port, int break_state)
707 {
708 	struct max3100_port *s = container_of(port,
709 					      struct max3100_port,
710 					      port);
711 
712 	dev_dbg(&s->spi->dev, "%s\n", __func__);
713 }
714 
715 static struct uart_ops max3100_ops = {
716 	.tx_empty	= max3100_tx_empty,
717 	.set_mctrl	= max3100_set_mctrl,
718 	.get_mctrl	= max3100_get_mctrl,
719 	.stop_tx        = max3100_stop_tx,
720 	.start_tx	= max3100_start_tx,
721 	.stop_rx	= max3100_stop_rx,
722 	.enable_ms      = max3100_enable_ms,
723 	.break_ctl      = max3100_break_ctl,
724 	.startup	= max3100_startup,
725 	.shutdown	= max3100_shutdown,
726 	.set_termios	= max3100_set_termios,
727 	.type		= max3100_type,
728 	.release_port   = max3100_release_port,
729 	.request_port   = max3100_request_port,
730 	.config_port	= max3100_config_port,
731 	.verify_port	= max3100_verify_port,
732 };
733 
734 static struct uart_driver max3100_uart_driver = {
735 	.owner          = THIS_MODULE,
736 	.driver_name    = "ttyMAX",
737 	.dev_name       = "ttyMAX",
738 	.major          = MAX3100_MAJOR,
739 	.minor          = MAX3100_MINOR,
740 	.nr             = MAX_MAX3100,
741 };
742 static int uart_driver_registered;
743 
744 static int max3100_probe(struct spi_device *spi)
745 {
746 	int i, retval;
747 	struct plat_max3100 *pdata;
748 	u16 tx, rx;
749 
750 	mutex_lock(&max3100s_lock);
751 
752 	if (!uart_driver_registered) {
753 		uart_driver_registered = 1;
754 		retval = uart_register_driver(&max3100_uart_driver);
755 		if (retval) {
756 			printk(KERN_ERR "Couldn't register max3100 uart driver\n");
757 			mutex_unlock(&max3100s_lock);
758 			return retval;
759 		}
760 	}
761 
762 	for (i = 0; i < MAX_MAX3100; i++)
763 		if (!max3100s[i])
764 			break;
765 	if (i == MAX_MAX3100) {
766 		dev_warn(&spi->dev, "too many MAX3100 chips\n");
767 		mutex_unlock(&max3100s_lock);
768 		return -ENOMEM;
769 	}
770 
771 	max3100s[i] = kzalloc(sizeof(struct max3100_port), GFP_KERNEL);
772 	if (!max3100s[i]) {
773 		dev_warn(&spi->dev,
774 			 "kmalloc for max3100 structure %d failed!\n", i);
775 		mutex_unlock(&max3100s_lock);
776 		return -ENOMEM;
777 	}
778 	max3100s[i]->spi = spi;
779 	max3100s[i]->irq = spi->irq;
780 	spin_lock_init(&max3100s[i]->conf_lock);
781 	spi_set_drvdata(spi, max3100s[i]);
782 	pdata = dev_get_platdata(&spi->dev);
783 	max3100s[i]->crystal = pdata->crystal;
784 	max3100s[i]->loopback = pdata->loopback;
785 	max3100s[i]->poll_time = msecs_to_jiffies(pdata->poll_time);
786 	if (pdata->poll_time > 0 && max3100s[i]->poll_time == 0)
787 		max3100s[i]->poll_time = 1;
788 	max3100s[i]->max3100_hw_suspend = pdata->max3100_hw_suspend;
789 	max3100s[i]->minor = i;
790 	init_timer(&max3100s[i]->timer);
791 	max3100s[i]->timer.function = max3100_timeout;
792 	max3100s[i]->timer.data = (unsigned long) max3100s[i];
793 
794 	dev_dbg(&spi->dev, "%s: adding port %d\n", __func__, i);
795 	max3100s[i]->port.irq = max3100s[i]->irq;
796 	max3100s[i]->port.uartclk = max3100s[i]->crystal ? 3686400 : 1843200;
797 	max3100s[i]->port.fifosize = 16;
798 	max3100s[i]->port.ops = &max3100_ops;
799 	max3100s[i]->port.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
800 	max3100s[i]->port.line = i;
801 	max3100s[i]->port.type = PORT_MAX3100;
802 	max3100s[i]->port.dev = &spi->dev;
803 	retval = uart_add_one_port(&max3100_uart_driver, &max3100s[i]->port);
804 	if (retval < 0)
805 		dev_warn(&spi->dev,
806 			 "uart_add_one_port failed for line %d with error %d\n",
807 			 i, retval);
808 
809 	/* set shutdown mode to save power. Will be woken-up on open */
810 	if (max3100s[i]->max3100_hw_suspend)
811 		max3100s[i]->max3100_hw_suspend(1);
812 	else {
813 		tx = MAX3100_WC | MAX3100_SHDN;
814 		max3100_sr(max3100s[i], tx, &rx);
815 	}
816 	mutex_unlock(&max3100s_lock);
817 	return 0;
818 }
819 
820 static int max3100_remove(struct spi_device *spi)
821 {
822 	struct max3100_port *s = spi_get_drvdata(spi);
823 	int i;
824 
825 	mutex_lock(&max3100s_lock);
826 
827 	/* find out the index for the chip we are removing */
828 	for (i = 0; i < MAX_MAX3100; i++)
829 		if (max3100s[i] == s) {
830 			dev_dbg(&spi->dev, "%s: removing port %d\n", __func__, i);
831 			uart_remove_one_port(&max3100_uart_driver, &max3100s[i]->port);
832 			kfree(max3100s[i]);
833 			max3100s[i] = NULL;
834 			break;
835 		}
836 
837 	WARN_ON(i == MAX_MAX3100);
838 
839 	/* check if this is the last chip we have */
840 	for (i = 0; i < MAX_MAX3100; i++)
841 		if (max3100s[i]) {
842 			mutex_unlock(&max3100s_lock);
843 			return 0;
844 		}
845 	pr_debug("removing max3100 driver\n");
846 	uart_unregister_driver(&max3100_uart_driver);
847 
848 	mutex_unlock(&max3100s_lock);
849 	return 0;
850 }
851 
852 #ifdef CONFIG_PM_SLEEP
853 
854 static int max3100_suspend(struct device *dev)
855 {
856 	struct max3100_port *s = dev_get_drvdata(dev);
857 
858 	dev_dbg(&s->spi->dev, "%s\n", __func__);
859 
860 	disable_irq(s->irq);
861 
862 	s->suspending = 1;
863 	uart_suspend_port(&max3100_uart_driver, &s->port);
864 
865 	if (s->max3100_hw_suspend)
866 		s->max3100_hw_suspend(1);
867 	else {
868 		/* no HW suspend, so do SW one */
869 		u16 tx, rx;
870 
871 		tx = MAX3100_WC | MAX3100_SHDN;
872 		max3100_sr(s, tx, &rx);
873 	}
874 	return 0;
875 }
876 
877 static int max3100_resume(struct device *dev)
878 {
879 	struct max3100_port *s = dev_get_drvdata(dev);
880 
881 	dev_dbg(&s->spi->dev, "%s\n", __func__);
882 
883 	if (s->max3100_hw_suspend)
884 		s->max3100_hw_suspend(0);
885 	uart_resume_port(&max3100_uart_driver, &s->port);
886 	s->suspending = 0;
887 
888 	enable_irq(s->irq);
889 
890 	s->conf_commit = 1;
891 	if (s->workqueue)
892 		max3100_dowork(s);
893 
894 	return 0;
895 }
896 
897 static SIMPLE_DEV_PM_OPS(max3100_pm_ops, max3100_suspend, max3100_resume);
898 #define MAX3100_PM_OPS (&max3100_pm_ops)
899 
900 #else
901 #define MAX3100_PM_OPS NULL
902 #endif
903 
904 static struct spi_driver max3100_driver = {
905 	.driver = {
906 		.name		= "max3100",
907 		.owner		= THIS_MODULE,
908 		.pm		= MAX3100_PM_OPS,
909 	},
910 	.probe		= max3100_probe,
911 	.remove		= max3100_remove,
912 };
913 
914 module_spi_driver(max3100_driver);
915 
916 MODULE_DESCRIPTION("MAX3100 driver");
917 MODULE_AUTHOR("Christian Pellegrin <chripell@evolware.org>");
918 MODULE_LICENSE("GPL");
919 MODULE_ALIAS("spi:max3100");
920