xref: /openbmc/linux/drivers/tty/serial/altera_uart.c (revision 2d96b44f) 
1 /*
2  * altera_uart.c -- Altera UART driver
3  *
4  * Based on mcf.c -- Freescale ColdFire UART driver
5  *
6  * (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com>
7  * (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw>
8  * (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  */
15 
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/timer.h>
19 #include <linux/interrupt.h>
20 #include <linux/module.h>
21 #include <linux/console.h>
22 #include <linux/tty.h>
23 #include <linux/tty_flip.h>
24 #include <linux/serial.h>
25 #include <linux/serial_core.h>
26 #include <linux/platform_device.h>
27 #include <linux/of.h>
28 #include <linux/io.h>
29 #include <linux/altera_uart.h>
30 
31 #define DRV_NAME "altera_uart"
32 #define SERIAL_ALTERA_MAJOR 204
33 #define SERIAL_ALTERA_MINOR 213
34 
35 /*
36  * Altera UART register definitions according to the Nios UART datasheet:
37  * http://www.altera.com/literature/ds/ds_nios_uart.pdf
38  */
39 
40 #define ALTERA_UART_SIZE		32
41 
42 #define ALTERA_UART_RXDATA_REG		0
43 #define ALTERA_UART_TXDATA_REG		4
44 #define ALTERA_UART_STATUS_REG		8
45 #define ALTERA_UART_CONTROL_REG		12
46 #define ALTERA_UART_DIVISOR_REG		16
47 #define ALTERA_UART_EOP_REG		20
48 
49 #define ALTERA_UART_STATUS_PE_MSK	0x0001	/* parity error */
50 #define ALTERA_UART_STATUS_FE_MSK	0x0002	/* framing error */
51 #define ALTERA_UART_STATUS_BRK_MSK	0x0004	/* break */
52 #define ALTERA_UART_STATUS_ROE_MSK	0x0008	/* RX overrun error */
53 #define ALTERA_UART_STATUS_TOE_MSK	0x0010	/* TX overrun error */
54 #define ALTERA_UART_STATUS_TMT_MSK	0x0020	/* TX shift register state */
55 #define ALTERA_UART_STATUS_TRDY_MSK	0x0040	/* TX ready */
56 #define ALTERA_UART_STATUS_RRDY_MSK	0x0080	/* RX ready */
57 #define ALTERA_UART_STATUS_E_MSK	0x0100	/* exception condition */
58 #define ALTERA_UART_STATUS_DCTS_MSK	0x0400	/* CTS logic-level change */
59 #define ALTERA_UART_STATUS_CTS_MSK	0x0800	/* CTS logic state */
60 #define ALTERA_UART_STATUS_EOP_MSK	0x1000	/* EOP written/read */
61 
62 						/* Enable interrupt on... */
63 #define ALTERA_UART_CONTROL_PE_MSK	0x0001	/* ...parity error */
64 #define ALTERA_UART_CONTROL_FE_MSK	0x0002	/* ...framing error */
65 #define ALTERA_UART_CONTROL_BRK_MSK	0x0004	/* ...break */
66 #define ALTERA_UART_CONTROL_ROE_MSK	0x0008	/* ...RX overrun */
67 #define ALTERA_UART_CONTROL_TOE_MSK	0x0010	/* ...TX overrun */
68 #define ALTERA_UART_CONTROL_TMT_MSK	0x0020	/* ...TX shift register empty */
69 #define ALTERA_UART_CONTROL_TRDY_MSK	0x0040	/* ...TX ready */
70 #define ALTERA_UART_CONTROL_RRDY_MSK	0x0080	/* ...RX ready */
71 #define ALTERA_UART_CONTROL_E_MSK	0x0100	/* ...exception*/
72 
73 #define ALTERA_UART_CONTROL_TRBK_MSK	0x0200	/* TX break */
74 #define ALTERA_UART_CONTROL_DCTS_MSK	0x0400	/* Interrupt on CTS change */
75 #define ALTERA_UART_CONTROL_RTS_MSK	0x0800	/* RTS signal */
76 #define ALTERA_UART_CONTROL_EOP_MSK	0x1000	/* Interrupt on EOP */
77 
78 /*
79  * Local per-uart structure.
80  */
81 struct altera_uart {
82 	struct uart_port port;
83 	struct timer_list tmr;
84 	unsigned int sigs;	/* Local copy of line sigs */
85 	unsigned short imr;	/* Local IMR mirror */
86 };
87 
88 static u32 altera_uart_readl(struct uart_port *port, int reg)
89 {
90 	return readl(port->membase + (reg << port->regshift));
91 }
92 
93 static void altera_uart_writel(struct uart_port *port, u32 dat, int reg)
94 {
95 	writel(dat, port->membase + (reg << port->regshift));
96 }
97 
98 static unsigned int altera_uart_tx_empty(struct uart_port *port)
99 {
100 	return (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
101 		ALTERA_UART_STATUS_TMT_MSK) ? TIOCSER_TEMT : 0;
102 }
103 
104 static unsigned int altera_uart_get_mctrl(struct uart_port *port)
105 {
106 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
107 	unsigned int sigs;
108 
109 	sigs = (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
110 	     ALTERA_UART_STATUS_CTS_MSK) ? TIOCM_CTS : 0;
111 	sigs |= (pp->sigs & TIOCM_RTS);
112 
113 	return sigs;
114 }
115 
116 static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs)
117 {
118 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
119 
120 	pp->sigs = sigs;
121 	if (sigs & TIOCM_RTS)
122 		pp->imr |= ALTERA_UART_CONTROL_RTS_MSK;
123 	else
124 		pp->imr &= ~ALTERA_UART_CONTROL_RTS_MSK;
125 	altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
126 }
127 
128 static void altera_uart_start_tx(struct uart_port *port)
129 {
130 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
131 
132 	pp->imr |= ALTERA_UART_CONTROL_TRDY_MSK;
133 	altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
134 }
135 
136 static void altera_uart_stop_tx(struct uart_port *port)
137 {
138 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
139 
140 	pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
141 	altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
142 }
143 
144 static void altera_uart_stop_rx(struct uart_port *port)
145 {
146 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
147 
148 	pp->imr &= ~ALTERA_UART_CONTROL_RRDY_MSK;
149 	altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
150 }
151 
152 static void altera_uart_break_ctl(struct uart_port *port, int break_state)
153 {
154 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
155 	unsigned long flags;
156 
157 	spin_lock_irqsave(&port->lock, flags);
158 	if (break_state == -1)
159 		pp->imr |= ALTERA_UART_CONTROL_TRBK_MSK;
160 	else
161 		pp->imr &= ~ALTERA_UART_CONTROL_TRBK_MSK;
162 	altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
163 	spin_unlock_irqrestore(&port->lock, flags);
164 }
165 
166 static void altera_uart_set_termios(struct uart_port *port,
167 				    struct ktermios *termios,
168 				    struct ktermios *old)
169 {
170 	unsigned long flags;
171 	unsigned int baud, baudclk;
172 
173 	baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
174 	baudclk = port->uartclk / baud;
175 
176 	if (old)
177 		tty_termios_copy_hw(termios, old);
178 	tty_termios_encode_baud_rate(termios, baud, baud);
179 
180 	spin_lock_irqsave(&port->lock, flags);
181 	uart_update_timeout(port, termios->c_cflag, baud);
182 	altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG);
183 	spin_unlock_irqrestore(&port->lock, flags);
184 
185 	/*
186 	 * FIXME: port->read_status_mask and port->ignore_status_mask
187 	 * need to be initialized based on termios settings for
188 	 * INPCK, IGNBRK, IGNPAR, PARMRK, BRKINT
189 	 */
190 }
191 
192 static void altera_uart_rx_chars(struct altera_uart *pp)
193 {
194 	struct uart_port *port = &pp->port;
195 	unsigned char ch, flag;
196 	unsigned short status;
197 
198 	while ((status = altera_uart_readl(port, ALTERA_UART_STATUS_REG)) &
199 	       ALTERA_UART_STATUS_RRDY_MSK) {
200 		ch = altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
201 		flag = TTY_NORMAL;
202 		port->icount.rx++;
203 
204 		if (status & ALTERA_UART_STATUS_E_MSK) {
205 			altera_uart_writel(port, status,
206 					   ALTERA_UART_STATUS_REG);
207 
208 			if (status & ALTERA_UART_STATUS_BRK_MSK) {
209 				port->icount.brk++;
210 				if (uart_handle_break(port))
211 					continue;
212 			} else if (status & ALTERA_UART_STATUS_PE_MSK) {
213 				port->icount.parity++;
214 			} else if (status & ALTERA_UART_STATUS_ROE_MSK) {
215 				port->icount.overrun++;
216 			} else if (status & ALTERA_UART_STATUS_FE_MSK) {
217 				port->icount.frame++;
218 			}
219 
220 			status &= port->read_status_mask;
221 
222 			if (status & ALTERA_UART_STATUS_BRK_MSK)
223 				flag = TTY_BREAK;
224 			else if (status & ALTERA_UART_STATUS_PE_MSK)
225 				flag = TTY_PARITY;
226 			else if (status & ALTERA_UART_STATUS_FE_MSK)
227 				flag = TTY_FRAME;
228 		}
229 
230 		if (uart_handle_sysrq_char(port, ch))
231 			continue;
232 		uart_insert_char(port, status, ALTERA_UART_STATUS_ROE_MSK, ch,
233 				 flag);
234 	}
235 
236 	spin_unlock(&port->lock);
237 	tty_flip_buffer_push(&port->state->port);
238 	spin_lock(&port->lock);
239 }
240 
241 static void altera_uart_tx_chars(struct altera_uart *pp)
242 {
243 	struct uart_port *port = &pp->port;
244 	struct circ_buf *xmit = &port->state->xmit;
245 
246 	if (port->x_char) {
247 		/* Send special char - probably flow control */
248 		altera_uart_writel(port, port->x_char, ALTERA_UART_TXDATA_REG);
249 		port->x_char = 0;
250 		port->icount.tx++;
251 		return;
252 	}
253 
254 	while (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
255 	       ALTERA_UART_STATUS_TRDY_MSK) {
256 		if (xmit->head == xmit->tail)
257 			break;
258 		altera_uart_writel(port, xmit->buf[xmit->tail],
259 		       ALTERA_UART_TXDATA_REG);
260 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
261 		port->icount.tx++;
262 	}
263 
264 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
265 		uart_write_wakeup(port);
266 
267 	if (xmit->head == xmit->tail) {
268 		pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
269 		altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
270 	}
271 }
272 
273 static irqreturn_t altera_uart_interrupt(int irq, void *data)
274 {
275 	struct uart_port *port = data;
276 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
277 	unsigned int isr;
278 
279 	isr = altera_uart_readl(port, ALTERA_UART_STATUS_REG) & pp->imr;
280 
281 	spin_lock(&port->lock);
282 	if (isr & ALTERA_UART_STATUS_RRDY_MSK)
283 		altera_uart_rx_chars(pp);
284 	if (isr & ALTERA_UART_STATUS_TRDY_MSK)
285 		altera_uart_tx_chars(pp);
286 	spin_unlock(&port->lock);
287 
288 	return IRQ_RETVAL(isr);
289 }
290 
291 static void altera_uart_timer(unsigned long data)
292 {
293 	struct uart_port *port = (void *)data;
294 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
295 
296 	altera_uart_interrupt(0, port);
297 	mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
298 }
299 
300 static void altera_uart_config_port(struct uart_port *port, int flags)
301 {
302 	port->type = PORT_ALTERA_UART;
303 
304 	/* Clear mask, so no surprise interrupts. */
305 	altera_uart_writel(port, 0, ALTERA_UART_CONTROL_REG);
306 	/* Clear status register */
307 	altera_uart_writel(port, 0, ALTERA_UART_STATUS_REG);
308 }
309 
310 static int altera_uart_startup(struct uart_port *port)
311 {
312 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
313 	unsigned long flags;
314 	int ret;
315 
316 	if (!port->irq) {
317 		setup_timer(&pp->tmr, altera_uart_timer, (unsigned long)port);
318 		mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
319 		return 0;
320 	}
321 
322 	ret = request_irq(port->irq, altera_uart_interrupt, 0,
323 			DRV_NAME, port);
324 	if (ret) {
325 		pr_err(DRV_NAME ": unable to attach Altera UART %d "
326 		       "interrupt vector=%d\n", port->line, port->irq);
327 		return ret;
328 	}
329 
330 	spin_lock_irqsave(&port->lock, flags);
331 
332 	/* Enable RX interrupts now */
333 	pp->imr = ALTERA_UART_CONTROL_RRDY_MSK;
334 	writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
335 
336 	spin_unlock_irqrestore(&port->lock, flags);
337 
338 	return 0;
339 }
340 
341 static void altera_uart_shutdown(struct uart_port *port)
342 {
343 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
344 	unsigned long flags;
345 
346 	spin_lock_irqsave(&port->lock, flags);
347 
348 	/* Disable all interrupts now */
349 	pp->imr = 0;
350 	writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
351 
352 	spin_unlock_irqrestore(&port->lock, flags);
353 
354 	if (port->irq)
355 		free_irq(port->irq, port);
356 	else
357 		del_timer_sync(&pp->tmr);
358 }
359 
360 static const char *altera_uart_type(struct uart_port *port)
361 {
362 	return (port->type == PORT_ALTERA_UART) ? "Altera UART" : NULL;
363 }
364 
365 static int altera_uart_request_port(struct uart_port *port)
366 {
367 	/* UARTs always present */
368 	return 0;
369 }
370 
371 static void altera_uart_release_port(struct uart_port *port)
372 {
373 	/* Nothing to release... */
374 }
375 
376 static int altera_uart_verify_port(struct uart_port *port,
377 				   struct serial_struct *ser)
378 {
379 	if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_ALTERA_UART))
380 		return -EINVAL;
381 	return 0;
382 }
383 
384 #ifdef CONFIG_CONSOLE_POLL
385 static int altera_uart_poll_get_char(struct uart_port *port)
386 {
387 	while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
388 		 ALTERA_UART_STATUS_RRDY_MSK))
389 		cpu_relax();
390 
391 	return altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
392 }
393 
394 static void altera_uart_poll_put_char(struct uart_port *port, unsigned char c)
395 {
396 	while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
397 		 ALTERA_UART_STATUS_TRDY_MSK))
398 		cpu_relax();
399 
400 	altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
401 }
402 #endif
403 
404 /*
405  *	Define the basic serial functions we support.
406  */
407 static const struct uart_ops altera_uart_ops = {
408 	.tx_empty	= altera_uart_tx_empty,
409 	.get_mctrl	= altera_uart_get_mctrl,
410 	.set_mctrl	= altera_uart_set_mctrl,
411 	.start_tx	= altera_uart_start_tx,
412 	.stop_tx	= altera_uart_stop_tx,
413 	.stop_rx	= altera_uart_stop_rx,
414 	.break_ctl	= altera_uart_break_ctl,
415 	.startup	= altera_uart_startup,
416 	.shutdown	= altera_uart_shutdown,
417 	.set_termios	= altera_uart_set_termios,
418 	.type		= altera_uart_type,
419 	.request_port	= altera_uart_request_port,
420 	.release_port	= altera_uart_release_port,
421 	.config_port	= altera_uart_config_port,
422 	.verify_port	= altera_uart_verify_port,
423 #ifdef CONFIG_CONSOLE_POLL
424 	.poll_get_char	= altera_uart_poll_get_char,
425 	.poll_put_char	= altera_uart_poll_put_char,
426 #endif
427 };
428 
429 static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS];
430 
431 #if defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
432 
433 static void altera_uart_console_putc(struct uart_port *port, int c)
434 {
435 	while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
436 		 ALTERA_UART_STATUS_TRDY_MSK))
437 		cpu_relax();
438 
439 	writel(c, port->membase + ALTERA_UART_TXDATA_REG);
440 }
441 
442 static void altera_uart_console_write(struct console *co, const char *s,
443 				      unsigned int count)
444 {
445 	struct uart_port *port = &(altera_uart_ports + co->index)->port;
446 
447 	uart_console_write(port, s, count, altera_uart_console_putc);
448 }
449 
450 static int __init altera_uart_console_setup(struct console *co, char *options)
451 {
452 	struct uart_port *port;
453 	int baud = CONFIG_SERIAL_ALTERA_UART_BAUDRATE;
454 	int bits = 8;
455 	int parity = 'n';
456 	int flow = 'n';
457 
458 	if (co->index < 0 || co->index >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
459 		return -EINVAL;
460 	port = &altera_uart_ports[co->index].port;
461 	if (!port->membase)
462 		return -ENODEV;
463 
464 	if (options)
465 		uart_parse_options(options, &baud, &parity, &bits, &flow);
466 
467 	return uart_set_options(port, co, baud, parity, bits, flow);
468 }
469 
470 static struct uart_driver altera_uart_driver;
471 
472 static struct console altera_uart_console = {
473 	.name	= "ttyAL",
474 	.write	= altera_uart_console_write,
475 	.device	= uart_console_device,
476 	.setup	= altera_uart_console_setup,
477 	.flags	= CON_PRINTBUFFER,
478 	.index	= -1,
479 	.data	= &altera_uart_driver,
480 };
481 
482 static int __init altera_uart_console_init(void)
483 {
484 	register_console(&altera_uart_console);
485 	return 0;
486 }
487 
488 console_initcall(altera_uart_console_init);
489 
490 #define	ALTERA_UART_CONSOLE	(&altera_uart_console)
491 
492 #else
493 
494 #define	ALTERA_UART_CONSOLE	NULL
495 
496 #endif /* CONFIG_SERIAL_ALTERA_UART_CONSOLE */
497 
498 /*
499  *	Define the altera_uart UART driver structure.
500  */
501 static struct uart_driver altera_uart_driver = {
502 	.owner		= THIS_MODULE,
503 	.driver_name	= DRV_NAME,
504 	.dev_name	= "ttyAL",
505 	.major		= SERIAL_ALTERA_MAJOR,
506 	.minor		= SERIAL_ALTERA_MINOR,
507 	.nr		= CONFIG_SERIAL_ALTERA_UART_MAXPORTS,
508 	.cons		= ALTERA_UART_CONSOLE,
509 };
510 
511 static int altera_uart_probe(struct platform_device *pdev)
512 {
513 	struct altera_uart_platform_uart *platp = dev_get_platdata(&pdev->dev);
514 	struct uart_port *port;
515 	struct resource *res_mem;
516 	struct resource *res_irq;
517 	int i = pdev->id;
518 	int ret;
519 
520 	/* if id is -1 scan for a free id and use that one */
521 	if (i == -1) {
522 		for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS; i++)
523 			if (altera_uart_ports[i].port.mapbase == 0)
524 				break;
525 	}
526 
527 	if (i < 0 || i >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
528 		return -EINVAL;
529 
530 	port = &altera_uart_ports[i].port;
531 
532 	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
533 	if (res_mem)
534 		port->mapbase = res_mem->start;
535 	else if (platp)
536 		port->mapbase = platp->mapbase;
537 	else
538 		return -EINVAL;
539 
540 	res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
541 	if (res_irq)
542 		port->irq = res_irq->start;
543 	else if (platp)
544 		port->irq = platp->irq;
545 
546 	/* Check platform data first so we can override device node data */
547 	if (platp)
548 		port->uartclk = platp->uartclk;
549 	else {
550 		ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
551 					   &port->uartclk);
552 		if (ret)
553 			return ret;
554 	}
555 
556 	port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE);
557 	if (!port->membase)
558 		return -ENOMEM;
559 
560 	if (platp)
561 		port->regshift = platp->bus_shift;
562 	else
563 		port->regshift = 0;
564 
565 	port->line = i;
566 	port->type = PORT_ALTERA_UART;
567 	port->iotype = SERIAL_IO_MEM;
568 	port->ops = &altera_uart_ops;
569 	port->flags = UPF_BOOT_AUTOCONF;
570 	port->dev = &pdev->dev;
571 
572 	platform_set_drvdata(pdev, port);
573 
574 	uart_add_one_port(&altera_uart_driver, port);
575 
576 	return 0;
577 }
578 
579 static int altera_uart_remove(struct platform_device *pdev)
580 {
581 	struct uart_port *port = platform_get_drvdata(pdev);
582 
583 	if (port) {
584 		uart_remove_one_port(&altera_uart_driver, port);
585 		port->mapbase = 0;
586 	}
587 
588 	return 0;
589 }
590 
591 #ifdef CONFIG_OF
592 static const struct of_device_id altera_uart_match[] = {
593 	{ .compatible = "ALTR,uart-1.0", },
594 	{ .compatible = "altr,uart-1.0", },
595 	{},
596 };
597 MODULE_DEVICE_TABLE(of, altera_uart_match);
598 #endif /* CONFIG_OF */
599 
600 static struct platform_driver altera_uart_platform_driver = {
601 	.probe	= altera_uart_probe,
602 	.remove	= altera_uart_remove,
603 	.driver	= {
604 		.name		= DRV_NAME,
605 		.of_match_table	= of_match_ptr(altera_uart_match),
606 	},
607 };
608 
609 static int __init altera_uart_init(void)
610 {
611 	int rc;
612 
613 	rc = uart_register_driver(&altera_uart_driver);
614 	if (rc)
615 		return rc;
616 	rc = platform_driver_register(&altera_uart_platform_driver);
617 	if (rc)
618 		uart_unregister_driver(&altera_uart_driver);
619 	return rc;
620 }
621 
622 static void __exit altera_uart_exit(void)
623 {
624 	platform_driver_unregister(&altera_uart_platform_driver);
625 	uart_unregister_driver(&altera_uart_driver);
626 }
627 
628 module_init(altera_uart_init);
629 module_exit(altera_uart_exit);
630 
631 MODULE_DESCRIPTION("Altera UART driver");
632 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
633 MODULE_LICENSE("GPL");
634 MODULE_ALIAS("platform:" DRV_NAME);
635 MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_ALTERA_MAJOR);
636