xref: /openbmc/linux/drivers/tty/serial/altera_uart.c (revision 404e077a) 
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * altera_uart.c -- Altera UART driver
4  *
5  * Based on mcf.c -- Freescale ColdFire UART driver
6  *
7  * (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com>
8  * (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw>
9  * (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch>
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/init.h>
14 #include <linux/timer.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
17 #include <linux/console.h>
18 #include <linux/tty.h>
19 #include <linux/tty_flip.h>
20 #include <linux/serial.h>
21 #include <linux/serial_core.h>
22 #include <linux/platform_device.h>
23 #include <linux/of.h>
24 #include <linux/io.h>
25 #include <linux/altera_uart.h>
26 
27 #define DRV_NAME "altera_uart"
28 #define SERIAL_ALTERA_MAJOR 204
29 #define SERIAL_ALTERA_MINOR 213
30 
31 /*
32  * Altera UART register definitions according to the Nios UART datasheet:
33  * http://www.altera.com/literature/ds/ds_nios_uart.pdf
34  */
35 
36 #define ALTERA_UART_SIZE		32
37 
38 #define ALTERA_UART_RXDATA_REG		0
39 #define ALTERA_UART_TXDATA_REG		4
40 #define ALTERA_UART_STATUS_REG		8
41 #define ALTERA_UART_CONTROL_REG		12
42 #define ALTERA_UART_DIVISOR_REG		16
43 #define ALTERA_UART_EOP_REG		20
44 
45 #define ALTERA_UART_STATUS_PE_MSK	0x0001	/* parity error */
46 #define ALTERA_UART_STATUS_FE_MSK	0x0002	/* framing error */
47 #define ALTERA_UART_STATUS_BRK_MSK	0x0004	/* break */
48 #define ALTERA_UART_STATUS_ROE_MSK	0x0008	/* RX overrun error */
49 #define ALTERA_UART_STATUS_TOE_MSK	0x0010	/* TX overrun error */
50 #define ALTERA_UART_STATUS_TMT_MSK	0x0020	/* TX shift register state */
51 #define ALTERA_UART_STATUS_TRDY_MSK	0x0040	/* TX ready */
52 #define ALTERA_UART_STATUS_RRDY_MSK	0x0080	/* RX ready */
53 #define ALTERA_UART_STATUS_E_MSK	0x0100	/* exception condition */
54 #define ALTERA_UART_STATUS_DCTS_MSK	0x0400	/* CTS logic-level change */
55 #define ALTERA_UART_STATUS_CTS_MSK	0x0800	/* CTS logic state */
56 #define ALTERA_UART_STATUS_EOP_MSK	0x1000	/* EOP written/read */
57 
58 						/* Enable interrupt on... */
59 #define ALTERA_UART_CONTROL_PE_MSK	0x0001	/* ...parity error */
60 #define ALTERA_UART_CONTROL_FE_MSK	0x0002	/* ...framing error */
61 #define ALTERA_UART_CONTROL_BRK_MSK	0x0004	/* ...break */
62 #define ALTERA_UART_CONTROL_ROE_MSK	0x0008	/* ...RX overrun */
63 #define ALTERA_UART_CONTROL_TOE_MSK	0x0010	/* ...TX overrun */
64 #define ALTERA_UART_CONTROL_TMT_MSK	0x0020	/* ...TX shift register empty */
65 #define ALTERA_UART_CONTROL_TRDY_MSK	0x0040	/* ...TX ready */
66 #define ALTERA_UART_CONTROL_RRDY_MSK	0x0080	/* ...RX ready */
67 #define ALTERA_UART_CONTROL_E_MSK	0x0100	/* ...exception*/
68 
69 #define ALTERA_UART_CONTROL_TRBK_MSK	0x0200	/* TX break */
70 #define ALTERA_UART_CONTROL_DCTS_MSK	0x0400	/* Interrupt on CTS change */
71 #define ALTERA_UART_CONTROL_RTS_MSK	0x0800	/* RTS signal */
72 #define ALTERA_UART_CONTROL_EOP_MSK	0x1000	/* Interrupt on EOP */
73 
74 /*
75  * Local per-uart structure.
76  */
77 struct altera_uart {
78 	struct uart_port port;
79 	struct timer_list tmr;
80 	unsigned int sigs;	/* Local copy of line sigs */
81 	unsigned short imr;	/* Local IMR mirror */
82 };
83 
84 static u32 altera_uart_readl(struct uart_port *port, int reg)
85 {
86 	return readl(port->membase + (reg << port->regshift));
87 }
88 
89 static void altera_uart_writel(struct uart_port *port, u32 dat, int reg)
90 {
91 	writel(dat, port->membase + (reg << port->regshift));
92 }
93 
94 static unsigned int altera_uart_tx_empty(struct uart_port *port)
95 {
96 	return (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
97 		ALTERA_UART_STATUS_TMT_MSK) ? TIOCSER_TEMT : 0;
98 }
99 
100 static unsigned int altera_uart_get_mctrl(struct uart_port *port)
101 {
102 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
103 	unsigned int sigs;
104 
105 	sigs = (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
106 	     ALTERA_UART_STATUS_CTS_MSK) ? TIOCM_CTS : 0;
107 	sigs |= (pp->sigs & TIOCM_RTS);
108 
109 	return sigs;
110 }
111 
112 static void altera_uart_update_ctrl_reg(struct altera_uart *pp)
113 {
114 	unsigned short imr = pp->imr;
115 
116 	/*
117 	 * If the device doesn't have an irq, ensure that the irq bits are
118 	 * masked out to keep the irq line inactive.
119 	 */
120 	if (!pp->port.irq)
121 		imr &= ALTERA_UART_CONTROL_TRBK_MSK | ALTERA_UART_CONTROL_RTS_MSK;
122 
123 	altera_uart_writel(&pp->port, imr, ALTERA_UART_CONTROL_REG);
124 }
125 
126 static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs)
127 {
128 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
129 
130 	pp->sigs = sigs;
131 	if (sigs & TIOCM_RTS)
132 		pp->imr |= ALTERA_UART_CONTROL_RTS_MSK;
133 	else
134 		pp->imr &= ~ALTERA_UART_CONTROL_RTS_MSK;
135 	altera_uart_update_ctrl_reg(pp);
136 }
137 
138 static void altera_uart_start_tx(struct uart_port *port)
139 {
140 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
141 
142 	pp->imr |= ALTERA_UART_CONTROL_TRDY_MSK;
143 	altera_uart_update_ctrl_reg(pp);
144 }
145 
146 static void altera_uart_stop_tx(struct uart_port *port)
147 {
148 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
149 
150 	pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
151 	altera_uart_update_ctrl_reg(pp);
152 }
153 
154 static void altera_uart_stop_rx(struct uart_port *port)
155 {
156 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
157 
158 	pp->imr &= ~ALTERA_UART_CONTROL_RRDY_MSK;
159 	altera_uart_update_ctrl_reg(pp);
160 }
161 
162 static void altera_uart_break_ctl(struct uart_port *port, int break_state)
163 {
164 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
165 	unsigned long flags;
166 
167 	spin_lock_irqsave(&port->lock, flags);
168 	if (break_state == -1)
169 		pp->imr |= ALTERA_UART_CONTROL_TRBK_MSK;
170 	else
171 		pp->imr &= ~ALTERA_UART_CONTROL_TRBK_MSK;
172 	altera_uart_update_ctrl_reg(pp);
173 	spin_unlock_irqrestore(&port->lock, flags);
174 }
175 
176 static void altera_uart_set_termios(struct uart_port *port,
177 				    struct ktermios *termios,
178 				    const struct ktermios *old)
179 {
180 	unsigned long flags;
181 	unsigned int baud, baudclk;
182 
183 	baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
184 	baudclk = port->uartclk / baud;
185 
186 	if (old)
187 		tty_termios_copy_hw(termios, old);
188 	tty_termios_encode_baud_rate(termios, baud, baud);
189 
190 	spin_lock_irqsave(&port->lock, flags);
191 	uart_update_timeout(port, termios->c_cflag, baud);
192 	altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG);
193 	spin_unlock_irqrestore(&port->lock, flags);
194 
195 	/*
196 	 * FIXME: port->read_status_mask and port->ignore_status_mask
197 	 * need to be initialized based on termios settings for
198 	 * INPCK, IGNBRK, IGNPAR, PARMRK, BRKINT
199 	 */
200 }
201 
202 static void altera_uart_rx_chars(struct uart_port *port)
203 {
204 	unsigned char ch, flag;
205 	unsigned short status;
206 
207 	while ((status = altera_uart_readl(port, ALTERA_UART_STATUS_REG)) &
208 	       ALTERA_UART_STATUS_RRDY_MSK) {
209 		ch = altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
210 		flag = TTY_NORMAL;
211 		port->icount.rx++;
212 
213 		if (status & ALTERA_UART_STATUS_E_MSK) {
214 			altera_uart_writel(port, status,
215 					   ALTERA_UART_STATUS_REG);
216 
217 			if (status & ALTERA_UART_STATUS_BRK_MSK) {
218 				port->icount.brk++;
219 				if (uart_handle_break(port))
220 					continue;
221 			} else if (status & ALTERA_UART_STATUS_PE_MSK) {
222 				port->icount.parity++;
223 			} else if (status & ALTERA_UART_STATUS_ROE_MSK) {
224 				port->icount.overrun++;
225 			} else if (status & ALTERA_UART_STATUS_FE_MSK) {
226 				port->icount.frame++;
227 			}
228 
229 			status &= port->read_status_mask;
230 
231 			if (status & ALTERA_UART_STATUS_BRK_MSK)
232 				flag = TTY_BREAK;
233 			else if (status & ALTERA_UART_STATUS_PE_MSK)
234 				flag = TTY_PARITY;
235 			else if (status & ALTERA_UART_STATUS_FE_MSK)
236 				flag = TTY_FRAME;
237 		}
238 
239 		if (uart_handle_sysrq_char(port, ch))
240 			continue;
241 		uart_insert_char(port, status, ALTERA_UART_STATUS_ROE_MSK, ch,
242 				 flag);
243 	}
244 
245 	tty_flip_buffer_push(&port->state->port);
246 }
247 
248 static void altera_uart_tx_chars(struct uart_port *port)
249 {
250 	u8 ch;
251 
252 	uart_port_tx(port, ch,
253 		altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
254 		                ALTERA_UART_STATUS_TRDY_MSK,
255 		altera_uart_writel(port, ch, ALTERA_UART_TXDATA_REG));
256 }
257 
258 static irqreturn_t altera_uart_interrupt(int irq, void *data)
259 {
260 	struct uart_port *port = data;
261 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
262 	unsigned long flags;
263 	unsigned int isr;
264 
265 	isr = altera_uart_readl(port, ALTERA_UART_STATUS_REG) & pp->imr;
266 
267 	spin_lock_irqsave(&port->lock, flags);
268 	if (isr & ALTERA_UART_STATUS_RRDY_MSK)
269 		altera_uart_rx_chars(port);
270 	if (isr & ALTERA_UART_STATUS_TRDY_MSK)
271 		altera_uart_tx_chars(port);
272 	spin_unlock_irqrestore(&port->lock, flags);
273 
274 	return IRQ_RETVAL(isr);
275 }
276 
277 static void altera_uart_timer(struct timer_list *t)
278 {
279 	struct altera_uart *pp = from_timer(pp, t, tmr);
280 	struct uart_port *port = &pp->port;
281 
282 	altera_uart_interrupt(0, port);
283 	mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
284 }
285 
286 static void altera_uart_config_port(struct uart_port *port, int flags)
287 {
288 	port->type = PORT_ALTERA_UART;
289 
290 	/* Clear mask, so no surprise interrupts. */
291 	altera_uart_writel(port, 0, ALTERA_UART_CONTROL_REG);
292 	/* Clear status register */
293 	altera_uart_writel(port, 0, ALTERA_UART_STATUS_REG);
294 }
295 
296 static int altera_uart_startup(struct uart_port *port)
297 {
298 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
299 	unsigned long flags;
300 
301 	if (!port->irq) {
302 		timer_setup(&pp->tmr, altera_uart_timer, 0);
303 		mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
304 	} else {
305 		int ret;
306 
307 		ret = request_irq(port->irq, altera_uart_interrupt, 0,
308 				DRV_NAME, port);
309 		if (ret) {
310 			pr_err(DRV_NAME ": unable to attach Altera UART %d "
311 			       "interrupt vector=%d\n", port->line, port->irq);
312 			return ret;
313 		}
314 	}
315 
316 	spin_lock_irqsave(&port->lock, flags);
317 
318 	/* Enable RX interrupts now */
319 	pp->imr = ALTERA_UART_CONTROL_RRDY_MSK;
320 	altera_uart_update_ctrl_reg(pp);
321 
322 	spin_unlock_irqrestore(&port->lock, flags);
323 
324 	return 0;
325 }
326 
327 static void altera_uart_shutdown(struct uart_port *port)
328 {
329 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
330 	unsigned long flags;
331 
332 	spin_lock_irqsave(&port->lock, flags);
333 
334 	/* Disable all interrupts now */
335 	pp->imr = 0;
336 	altera_uart_update_ctrl_reg(pp);
337 
338 	spin_unlock_irqrestore(&port->lock, flags);
339 
340 	if (port->irq)
341 		free_irq(port->irq, port);
342 	else
343 		del_timer_sync(&pp->tmr);
344 }
345 
346 static const char *altera_uart_type(struct uart_port *port)
347 {
348 	return (port->type == PORT_ALTERA_UART) ? "Altera UART" : NULL;
349 }
350 
351 static int altera_uart_request_port(struct uart_port *port)
352 {
353 	/* UARTs always present */
354 	return 0;
355 }
356 
357 static void altera_uart_release_port(struct uart_port *port)
358 {
359 	/* Nothing to release... */
360 }
361 
362 static int altera_uart_verify_port(struct uart_port *port,
363 				   struct serial_struct *ser)
364 {
365 	if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_ALTERA_UART))
366 		return -EINVAL;
367 	return 0;
368 }
369 
370 #ifdef CONFIG_CONSOLE_POLL
371 static int altera_uart_poll_get_char(struct uart_port *port)
372 {
373 	while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
374 		 ALTERA_UART_STATUS_RRDY_MSK))
375 		cpu_relax();
376 
377 	return altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
378 }
379 
380 static void altera_uart_poll_put_char(struct uart_port *port, unsigned char c)
381 {
382 	while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
383 		 ALTERA_UART_STATUS_TRDY_MSK))
384 		cpu_relax();
385 
386 	altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
387 }
388 #endif
389 
390 /*
391  *	Define the basic serial functions we support.
392  */
393 static const struct uart_ops altera_uart_ops = {
394 	.tx_empty	= altera_uart_tx_empty,
395 	.get_mctrl	= altera_uart_get_mctrl,
396 	.set_mctrl	= altera_uart_set_mctrl,
397 	.start_tx	= altera_uart_start_tx,
398 	.stop_tx	= altera_uart_stop_tx,
399 	.stop_rx	= altera_uart_stop_rx,
400 	.break_ctl	= altera_uart_break_ctl,
401 	.startup	= altera_uart_startup,
402 	.shutdown	= altera_uart_shutdown,
403 	.set_termios	= altera_uart_set_termios,
404 	.type		= altera_uart_type,
405 	.request_port	= altera_uart_request_port,
406 	.release_port	= altera_uart_release_port,
407 	.config_port	= altera_uart_config_port,
408 	.verify_port	= altera_uart_verify_port,
409 #ifdef CONFIG_CONSOLE_POLL
410 	.poll_get_char	= altera_uart_poll_get_char,
411 	.poll_put_char	= altera_uart_poll_put_char,
412 #endif
413 };
414 
415 static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS];
416 
417 #if defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
418 
419 static void altera_uart_console_putc(struct uart_port *port, unsigned char c)
420 {
421 	while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
422 		 ALTERA_UART_STATUS_TRDY_MSK))
423 		cpu_relax();
424 
425 	altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
426 }
427 
428 static void altera_uart_console_write(struct console *co, const char *s,
429 				      unsigned int count)
430 {
431 	struct uart_port *port = &(altera_uart_ports + co->index)->port;
432 
433 	uart_console_write(port, s, count, altera_uart_console_putc);
434 }
435 
436 static int __init altera_uart_console_setup(struct console *co, char *options)
437 {
438 	struct uart_port *port;
439 	int baud = CONFIG_SERIAL_ALTERA_UART_BAUDRATE;
440 	int bits = 8;
441 	int parity = 'n';
442 	int flow = 'n';
443 
444 	if (co->index < 0 || co->index >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
445 		return -EINVAL;
446 	port = &altera_uart_ports[co->index].port;
447 	if (!port->membase)
448 		return -ENODEV;
449 
450 	if (options)
451 		uart_parse_options(options, &baud, &parity, &bits, &flow);
452 
453 	return uart_set_options(port, co, baud, parity, bits, flow);
454 }
455 
456 static struct uart_driver altera_uart_driver;
457 
458 static struct console altera_uart_console = {
459 	.name	= "ttyAL",
460 	.write	= altera_uart_console_write,
461 	.device	= uart_console_device,
462 	.setup	= altera_uart_console_setup,
463 	.flags	= CON_PRINTBUFFER,
464 	.index	= -1,
465 	.data	= &altera_uart_driver,
466 };
467 
468 static int __init altera_uart_console_init(void)
469 {
470 	register_console(&altera_uart_console);
471 	return 0;
472 }
473 
474 console_initcall(altera_uart_console_init);
475 
476 #define	ALTERA_UART_CONSOLE	(&altera_uart_console)
477 
478 static void altera_uart_earlycon_write(struct console *co, const char *s,
479 				       unsigned int count)
480 {
481 	struct earlycon_device *dev = co->data;
482 
483 	uart_console_write(&dev->port, s, count, altera_uart_console_putc);
484 }
485 
486 static int __init altera_uart_earlycon_setup(struct earlycon_device *dev,
487 					     const char *options)
488 {
489 	struct uart_port *port = &dev->port;
490 
491 	if (!port->membase)
492 		return -ENODEV;
493 
494 	/* Enable RX interrupts now */
495 	altera_uart_writel(port, ALTERA_UART_CONTROL_RRDY_MSK,
496 			   ALTERA_UART_CONTROL_REG);
497 
498 	if (dev->baud) {
499 		unsigned int baudclk = port->uartclk / dev->baud;
500 
501 		altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG);
502 	}
503 
504 	dev->con->write = altera_uart_earlycon_write;
505 	return 0;
506 }
507 
508 OF_EARLYCON_DECLARE(uart, "altr,uart-1.0", altera_uart_earlycon_setup);
509 
510 #else
511 
512 #define	ALTERA_UART_CONSOLE	NULL
513 
514 #endif /* CONFIG_SERIAL_ALTERA_UART_CONSOLE */
515 
516 /*
517  *	Define the altera_uart UART driver structure.
518  */
519 static struct uart_driver altera_uart_driver = {
520 	.owner		= THIS_MODULE,
521 	.driver_name	= DRV_NAME,
522 	.dev_name	= "ttyAL",
523 	.major		= SERIAL_ALTERA_MAJOR,
524 	.minor		= SERIAL_ALTERA_MINOR,
525 	.nr		= CONFIG_SERIAL_ALTERA_UART_MAXPORTS,
526 	.cons		= ALTERA_UART_CONSOLE,
527 };
528 
529 static int altera_uart_probe(struct platform_device *pdev)
530 {
531 	struct altera_uart_platform_uart *platp = dev_get_platdata(&pdev->dev);
532 	struct uart_port *port;
533 	struct resource *res_mem;
534 	int i = pdev->id;
535 	int ret;
536 
537 	/* if id is -1 scan for a free id and use that one */
538 	if (i == -1) {
539 		for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS; i++)
540 			if (altera_uart_ports[i].port.mapbase == 0)
541 				break;
542 	}
543 
544 	if (i < 0 || i >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
545 		return -EINVAL;
546 
547 	port = &altera_uart_ports[i].port;
548 
549 	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
550 	if (res_mem)
551 		port->mapbase = res_mem->start;
552 	else if (platp)
553 		port->mapbase = platp->mapbase;
554 	else
555 		return -EINVAL;
556 
557 	ret = platform_get_irq_optional(pdev, 0);
558 	if (ret < 0 && ret != -ENXIO)
559 		return ret;
560 	if (ret > 0)
561 		port->irq = ret;
562 	else if (platp)
563 		port->irq = platp->irq;
564 
565 	/* Check platform data first so we can override device node data */
566 	if (platp)
567 		port->uartclk = platp->uartclk;
568 	else {
569 		ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
570 					   &port->uartclk);
571 		if (ret)
572 			return ret;
573 	}
574 
575 	port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE);
576 	if (!port->membase)
577 		return -ENOMEM;
578 
579 	if (platp)
580 		port->regshift = platp->bus_shift;
581 	else
582 		port->regshift = 0;
583 
584 	port->line = i;
585 	port->type = PORT_ALTERA_UART;
586 	port->iotype = SERIAL_IO_MEM;
587 	port->ops = &altera_uart_ops;
588 	port->flags = UPF_BOOT_AUTOCONF;
589 	port->dev = &pdev->dev;
590 
591 	platform_set_drvdata(pdev, port);
592 
593 	uart_add_one_port(&altera_uart_driver, port);
594 
595 	return 0;
596 }
597 
598 static int altera_uart_remove(struct platform_device *pdev)
599 {
600 	struct uart_port *port = platform_get_drvdata(pdev);
601 
602 	if (port) {
603 		uart_remove_one_port(&altera_uart_driver, port);
604 		port->mapbase = 0;
605 		iounmap(port->membase);
606 	}
607 
608 	return 0;
609 }
610 
611 #ifdef CONFIG_OF
612 static const struct of_device_id altera_uart_match[] = {
613 	{ .compatible = "ALTR,uart-1.0", },
614 	{ .compatible = "altr,uart-1.0", },
615 	{},
616 };
617 MODULE_DEVICE_TABLE(of, altera_uart_match);
618 #endif /* CONFIG_OF */
619 
620 static struct platform_driver altera_uart_platform_driver = {
621 	.probe	= altera_uart_probe,
622 	.remove	= altera_uart_remove,
623 	.driver	= {
624 		.name		= DRV_NAME,
625 		.of_match_table	= of_match_ptr(altera_uart_match),
626 	},
627 };
628 
629 static int __init altera_uart_init(void)
630 {
631 	int rc;
632 
633 	rc = uart_register_driver(&altera_uart_driver);
634 	if (rc)
635 		return rc;
636 	rc = platform_driver_register(&altera_uart_platform_driver);
637 	if (rc)
638 		uart_unregister_driver(&altera_uart_driver);
639 	return rc;
640 }
641 
642 static void __exit altera_uart_exit(void)
643 {
644 	platform_driver_unregister(&altera_uart_platform_driver);
645 	uart_unregister_driver(&altera_uart_driver);
646 }
647 
648 module_init(altera_uart_init);
649 module_exit(altera_uart_exit);
650 
651 MODULE_DESCRIPTION("Altera UART driver");
652 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
653 MODULE_LICENSE("GPL");
654 MODULE_ALIAS("platform:" DRV_NAME);
655 MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_ALTERA_MAJOR);
656