xref: /openbmc/linux/drivers/tty/serial/uartlite.c (revision 6aa7de05) 
1 /*
2  * uartlite.c: Serial driver for Xilinx uartlite serial controller
3  *
4  * Copyright (C) 2006 Peter Korsgaard <jacmet@sunsite.dk>
5  * Copyright (C) 2007 Secret Lab Technologies Ltd.
6  *
7  * This file is licensed under the terms of the GNU General Public License
8  * version 2.  This program is licensed "as is" without any warranty of any
9  * kind, whether express or implied.
10  */
11 
12 #include <linux/platform_device.h>
13 #include <linux/module.h>
14 #include <linux/console.h>
15 #include <linux/serial.h>
16 #include <linux/serial_core.h>
17 #include <linux/tty.h>
18 #include <linux/tty_flip.h>
19 #include <linux/delay.h>
20 #include <linux/interrupt.h>
21 #include <linux/init.h>
22 #include <linux/io.h>
23 #include <linux/of.h>
24 #include <linux/of_address.h>
25 #include <linux/of_device.h>
26 #include <linux/of_platform.h>
27 
28 #define ULITE_NAME		"ttyUL"
29 #define ULITE_MAJOR		204
30 #define ULITE_MINOR		187
31 #define ULITE_NR_UARTS		CONFIG_SERIAL_UARTLITE_NR_UARTS
32 
33 /* ---------------------------------------------------------------------
34  * Register definitions
35  *
36  * For register details see datasheet:
37  * http://www.xilinx.com/support/documentation/ip_documentation/opb_uartlite.pdf
38  */
39 
40 #define ULITE_RX		0x00
41 #define ULITE_TX		0x04
42 #define ULITE_STATUS		0x08
43 #define ULITE_CONTROL		0x0c
44 
45 #define ULITE_REGION		16
46 
47 #define ULITE_STATUS_RXVALID	0x01
48 #define ULITE_STATUS_RXFULL	0x02
49 #define ULITE_STATUS_TXEMPTY	0x04
50 #define ULITE_STATUS_TXFULL	0x08
51 #define ULITE_STATUS_IE		0x10
52 #define ULITE_STATUS_OVERRUN	0x20
53 #define ULITE_STATUS_FRAME	0x40
54 #define ULITE_STATUS_PARITY	0x80
55 
56 #define ULITE_CONTROL_RST_TX	0x01
57 #define ULITE_CONTROL_RST_RX	0x02
58 #define ULITE_CONTROL_IE	0x10
59 
60 struct uartlite_reg_ops {
61 	u32 (*in)(void __iomem *addr);
62 	void (*out)(u32 val, void __iomem *addr);
63 };
64 
65 static u32 uartlite_inbe32(void __iomem *addr)
66 {
67 	return ioread32be(addr);
68 }
69 
70 static void uartlite_outbe32(u32 val, void __iomem *addr)
71 {
72 	iowrite32be(val, addr);
73 }
74 
75 static const struct uartlite_reg_ops uartlite_be = {
76 	.in = uartlite_inbe32,
77 	.out = uartlite_outbe32,
78 };
79 
80 static u32 uartlite_inle32(void __iomem *addr)
81 {
82 	return ioread32(addr);
83 }
84 
85 static void uartlite_outle32(u32 val, void __iomem *addr)
86 {
87 	iowrite32(val, addr);
88 }
89 
90 static const struct uartlite_reg_ops uartlite_le = {
91 	.in = uartlite_inle32,
92 	.out = uartlite_outle32,
93 };
94 
95 static inline u32 uart_in32(u32 offset, struct uart_port *port)
96 {
97 	const struct uartlite_reg_ops *reg_ops = port->private_data;
98 
99 	return reg_ops->in(port->membase + offset);
100 }
101 
102 static inline void uart_out32(u32 val, u32 offset, struct uart_port *port)
103 {
104 	const struct uartlite_reg_ops *reg_ops = port->private_data;
105 
106 	reg_ops->out(val, port->membase + offset);
107 }
108 
109 static struct uart_port ulite_ports[ULITE_NR_UARTS];
110 
111 /* ---------------------------------------------------------------------
112  * Core UART driver operations
113  */
114 
115 static int ulite_receive(struct uart_port *port, int stat)
116 {
117 	struct tty_port *tport = &port->state->port;
118 	unsigned char ch = 0;
119 	char flag = TTY_NORMAL;
120 
121 	if ((stat & (ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
122 		     | ULITE_STATUS_FRAME)) == 0)
123 		return 0;
124 
125 	/* stats */
126 	if (stat & ULITE_STATUS_RXVALID) {
127 		port->icount.rx++;
128 		ch = uart_in32(ULITE_RX, port);
129 
130 		if (stat & ULITE_STATUS_PARITY)
131 			port->icount.parity++;
132 	}
133 
134 	if (stat & ULITE_STATUS_OVERRUN)
135 		port->icount.overrun++;
136 
137 	if (stat & ULITE_STATUS_FRAME)
138 		port->icount.frame++;
139 
140 
141 	/* drop byte with parity error if IGNPAR specificed */
142 	if (stat & port->ignore_status_mask & ULITE_STATUS_PARITY)
143 		stat &= ~ULITE_STATUS_RXVALID;
144 
145 	stat &= port->read_status_mask;
146 
147 	if (stat & ULITE_STATUS_PARITY)
148 		flag = TTY_PARITY;
149 
150 
151 	stat &= ~port->ignore_status_mask;
152 
153 	if (stat & ULITE_STATUS_RXVALID)
154 		tty_insert_flip_char(tport, ch, flag);
155 
156 	if (stat & ULITE_STATUS_FRAME)
157 		tty_insert_flip_char(tport, 0, TTY_FRAME);
158 
159 	if (stat & ULITE_STATUS_OVERRUN)
160 		tty_insert_flip_char(tport, 0, TTY_OVERRUN);
161 
162 	return 1;
163 }
164 
165 static int ulite_transmit(struct uart_port *port, int stat)
166 {
167 	struct circ_buf *xmit  = &port->state->xmit;
168 
169 	if (stat & ULITE_STATUS_TXFULL)
170 		return 0;
171 
172 	if (port->x_char) {
173 		uart_out32(port->x_char, ULITE_TX, port);
174 		port->x_char = 0;
175 		port->icount.tx++;
176 		return 1;
177 	}
178 
179 	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
180 		return 0;
181 
182 	uart_out32(xmit->buf[xmit->tail], ULITE_TX, port);
183 	xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
184 	port->icount.tx++;
185 
186 	/* wake up */
187 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
188 		uart_write_wakeup(port);
189 
190 	return 1;
191 }
192 
193 static irqreturn_t ulite_isr(int irq, void *dev_id)
194 {
195 	struct uart_port *port = dev_id;
196 	int stat, busy, n = 0;
197 	unsigned long flags;
198 
199 	do {
200 		spin_lock_irqsave(&port->lock, flags);
201 		stat = uart_in32(ULITE_STATUS, port);
202 		busy  = ulite_receive(port, stat);
203 		busy |= ulite_transmit(port, stat);
204 		spin_unlock_irqrestore(&port->lock, flags);
205 		n++;
206 	} while (busy);
207 
208 	/* work done? */
209 	if (n > 1) {
210 		tty_flip_buffer_push(&port->state->port);
211 		return IRQ_HANDLED;
212 	} else {
213 		return IRQ_NONE;
214 	}
215 }
216 
217 static unsigned int ulite_tx_empty(struct uart_port *port)
218 {
219 	unsigned long flags;
220 	unsigned int ret;
221 
222 	spin_lock_irqsave(&port->lock, flags);
223 	ret = uart_in32(ULITE_STATUS, port);
224 	spin_unlock_irqrestore(&port->lock, flags);
225 
226 	return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0;
227 }
228 
229 static unsigned int ulite_get_mctrl(struct uart_port *port)
230 {
231 	return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
232 }
233 
234 static void ulite_set_mctrl(struct uart_port *port, unsigned int mctrl)
235 {
236 	/* N/A */
237 }
238 
239 static void ulite_stop_tx(struct uart_port *port)
240 {
241 	/* N/A */
242 }
243 
244 static void ulite_start_tx(struct uart_port *port)
245 {
246 	ulite_transmit(port, uart_in32(ULITE_STATUS, port));
247 }
248 
249 static void ulite_stop_rx(struct uart_port *port)
250 {
251 	/* don't forward any more data (like !CREAD) */
252 	port->ignore_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
253 		| ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
254 }
255 
256 static void ulite_break_ctl(struct uart_port *port, int ctl)
257 {
258 	/* N/A */
259 }
260 
261 static int ulite_startup(struct uart_port *port)
262 {
263 	int ret;
264 
265 	ret = request_irq(port->irq, ulite_isr, IRQF_SHARED | IRQF_TRIGGER_RISING,
266 			  "uartlite", port);
267 	if (ret)
268 		return ret;
269 
270 	uart_out32(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX,
271 		ULITE_CONTROL, port);
272 	uart_out32(ULITE_CONTROL_IE, ULITE_CONTROL, port);
273 
274 	return 0;
275 }
276 
277 static void ulite_shutdown(struct uart_port *port)
278 {
279 	uart_out32(0, ULITE_CONTROL, port);
280 	uart_in32(ULITE_CONTROL, port); /* dummy */
281 	free_irq(port->irq, port);
282 }
283 
284 static void ulite_set_termios(struct uart_port *port, struct ktermios *termios,
285 			      struct ktermios *old)
286 {
287 	unsigned long flags;
288 	unsigned int baud;
289 
290 	spin_lock_irqsave(&port->lock, flags);
291 
292 	port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
293 		| ULITE_STATUS_TXFULL;
294 
295 	if (termios->c_iflag & INPCK)
296 		port->read_status_mask |=
297 			ULITE_STATUS_PARITY | ULITE_STATUS_FRAME;
298 
299 	port->ignore_status_mask = 0;
300 	if (termios->c_iflag & IGNPAR)
301 		port->ignore_status_mask |= ULITE_STATUS_PARITY
302 			| ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
303 
304 	/* ignore all characters if CREAD is not set */
305 	if ((termios->c_cflag & CREAD) == 0)
306 		port->ignore_status_mask |=
307 			ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
308 			| ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
309 
310 	/* update timeout */
311 	baud = uart_get_baud_rate(port, termios, old, 0, 460800);
312 	uart_update_timeout(port, termios->c_cflag, baud);
313 
314 	spin_unlock_irqrestore(&port->lock, flags);
315 }
316 
317 static const char *ulite_type(struct uart_port *port)
318 {
319 	return port->type == PORT_UARTLITE ? "uartlite" : NULL;
320 }
321 
322 static void ulite_release_port(struct uart_port *port)
323 {
324 	release_mem_region(port->mapbase, ULITE_REGION);
325 	iounmap(port->membase);
326 	port->membase = NULL;
327 }
328 
329 static int ulite_request_port(struct uart_port *port)
330 {
331 	int ret;
332 
333 	pr_debug("ulite console: port=%p; port->mapbase=%llx\n",
334 		 port, (unsigned long long) port->mapbase);
335 
336 	if (!request_mem_region(port->mapbase, ULITE_REGION, "uartlite")) {
337 		dev_err(port->dev, "Memory region busy\n");
338 		return -EBUSY;
339 	}
340 
341 	port->membase = ioremap(port->mapbase, ULITE_REGION);
342 	if (!port->membase) {
343 		dev_err(port->dev, "Unable to map registers\n");
344 		release_mem_region(port->mapbase, ULITE_REGION);
345 		return -EBUSY;
346 	}
347 
348 	port->private_data = (void *)&uartlite_be;
349 	ret = uart_in32(ULITE_CONTROL, port);
350 	uart_out32(ULITE_CONTROL_RST_TX, ULITE_CONTROL, port);
351 	ret = uart_in32(ULITE_STATUS, port);
352 	/* Endianess detection */
353 	if ((ret & ULITE_STATUS_TXEMPTY) != ULITE_STATUS_TXEMPTY)
354 		port->private_data = (void *)&uartlite_le;
355 
356 	return 0;
357 }
358 
359 static void ulite_config_port(struct uart_port *port, int flags)
360 {
361 	if (!ulite_request_port(port))
362 		port->type = PORT_UARTLITE;
363 }
364 
365 static int ulite_verify_port(struct uart_port *port, struct serial_struct *ser)
366 {
367 	/* we don't want the core code to modify any port params */
368 	return -EINVAL;
369 }
370 
371 #ifdef CONFIG_CONSOLE_POLL
372 static int ulite_get_poll_char(struct uart_port *port)
373 {
374 	if (!(uart_in32(ULITE_STATUS, port) & ULITE_STATUS_RXVALID))
375 		return NO_POLL_CHAR;
376 
377 	return uart_in32(ULITE_RX, port);
378 }
379 
380 static void ulite_put_poll_char(struct uart_port *port, unsigned char ch)
381 {
382 	while (uart_in32(ULITE_STATUS, port) & ULITE_STATUS_TXFULL)
383 		cpu_relax();
384 
385 	/* write char to device */
386 	uart_out32(ch, ULITE_TX, port);
387 }
388 #endif
389 
390 static const struct uart_ops ulite_ops = {
391 	.tx_empty	= ulite_tx_empty,
392 	.set_mctrl	= ulite_set_mctrl,
393 	.get_mctrl	= ulite_get_mctrl,
394 	.stop_tx	= ulite_stop_tx,
395 	.start_tx	= ulite_start_tx,
396 	.stop_rx	= ulite_stop_rx,
397 	.break_ctl	= ulite_break_ctl,
398 	.startup	= ulite_startup,
399 	.shutdown	= ulite_shutdown,
400 	.set_termios	= ulite_set_termios,
401 	.type		= ulite_type,
402 	.release_port	= ulite_release_port,
403 	.request_port	= ulite_request_port,
404 	.config_port	= ulite_config_port,
405 	.verify_port	= ulite_verify_port,
406 #ifdef CONFIG_CONSOLE_POLL
407 	.poll_get_char	= ulite_get_poll_char,
408 	.poll_put_char	= ulite_put_poll_char,
409 #endif
410 };
411 
412 /* ---------------------------------------------------------------------
413  * Console driver operations
414  */
415 
416 #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
417 static void ulite_console_wait_tx(struct uart_port *port)
418 {
419 	u8 val;
420 	unsigned long timeout;
421 
422 	/*
423 	 * Spin waiting for TX fifo to have space available.
424 	 * When using the Microblaze Debug Module this can take up to 1s
425 	 */
426 	timeout = jiffies + msecs_to_jiffies(1000);
427 	while (1) {
428 		val = uart_in32(ULITE_STATUS, port);
429 		if ((val & ULITE_STATUS_TXFULL) == 0)
430 			break;
431 		if (time_after(jiffies, timeout)) {
432 			dev_warn(port->dev,
433 				 "timeout waiting for TX buffer empty\n");
434 			break;
435 		}
436 		cpu_relax();
437 	}
438 }
439 
440 static void ulite_console_putchar(struct uart_port *port, int ch)
441 {
442 	ulite_console_wait_tx(port);
443 	uart_out32(ch, ULITE_TX, port);
444 }
445 
446 static void ulite_console_write(struct console *co, const char *s,
447 				unsigned int count)
448 {
449 	struct uart_port *port = &ulite_ports[co->index];
450 	unsigned long flags;
451 	unsigned int ier;
452 	int locked = 1;
453 
454 	if (oops_in_progress) {
455 		locked = spin_trylock_irqsave(&port->lock, flags);
456 	} else
457 		spin_lock_irqsave(&port->lock, flags);
458 
459 	/* save and disable interrupt */
460 	ier = uart_in32(ULITE_STATUS, port) & ULITE_STATUS_IE;
461 	uart_out32(0, ULITE_CONTROL, port);
462 
463 	uart_console_write(port, s, count, ulite_console_putchar);
464 
465 	ulite_console_wait_tx(port);
466 
467 	/* restore interrupt state */
468 	if (ier)
469 		uart_out32(ULITE_CONTROL_IE, ULITE_CONTROL, port);
470 
471 	if (locked)
472 		spin_unlock_irqrestore(&port->lock, flags);
473 }
474 
475 static int ulite_console_setup(struct console *co, char *options)
476 {
477 	struct uart_port *port;
478 	int baud = 9600;
479 	int bits = 8;
480 	int parity = 'n';
481 	int flow = 'n';
482 
483 	if (co->index < 0 || co->index >= ULITE_NR_UARTS)
484 		return -EINVAL;
485 
486 	port = &ulite_ports[co->index];
487 
488 	/* Has the device been initialized yet? */
489 	if (!port->mapbase) {
490 		pr_debug("console on ttyUL%i not present\n", co->index);
491 		return -ENODEV;
492 	}
493 
494 	/* not initialized yet? */
495 	if (!port->membase) {
496 		if (ulite_request_port(port))
497 			return -ENODEV;
498 	}
499 
500 	if (options)
501 		uart_parse_options(options, &baud, &parity, &bits, &flow);
502 
503 	return uart_set_options(port, co, baud, parity, bits, flow);
504 }
505 
506 static struct uart_driver ulite_uart_driver;
507 
508 static struct console ulite_console = {
509 	.name	= ULITE_NAME,
510 	.write	= ulite_console_write,
511 	.device	= uart_console_device,
512 	.setup	= ulite_console_setup,
513 	.flags	= CON_PRINTBUFFER,
514 	.index	= -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */
515 	.data	= &ulite_uart_driver,
516 };
517 
518 static int __init ulite_console_init(void)
519 {
520 	register_console(&ulite_console);
521 	return 0;
522 }
523 
524 console_initcall(ulite_console_init);
525 
526 static void early_uartlite_putc(struct uart_port *port, int c)
527 {
528 	/*
529 	 * Limit how many times we'll spin waiting for TX FIFO status.
530 	 * This will prevent lockups if the base address is incorrectly
531 	 * set, or any other issue on the UARTLITE.
532 	 * This limit is pretty arbitrary, unless we are at about 10 baud
533 	 * we'll never timeout on a working UART.
534 	 */
535 
536 	unsigned retries = 1000000;
537 	/* read status bit - 0x8 offset */
538 	while (--retries && (readl(port->membase + 8) & (1 << 3)))
539 		;
540 
541 	/* Only attempt the iowrite if we didn't timeout */
542 	/* write to TX_FIFO - 0x4 offset */
543 	if (retries)
544 		writel(c & 0xff, port->membase + 4);
545 }
546 
547 static void early_uartlite_write(struct console *console,
548 				 const char *s, unsigned n)
549 {
550 	struct earlycon_device *device = console->data;
551 	uart_console_write(&device->port, s, n, early_uartlite_putc);
552 }
553 
554 static int __init early_uartlite_setup(struct earlycon_device *device,
555 				       const char *options)
556 {
557 	if (!device->port.membase)
558 		return -ENODEV;
559 
560 	device->con->write = early_uartlite_write;
561 	return 0;
562 }
563 EARLYCON_DECLARE(uartlite, early_uartlite_setup);
564 OF_EARLYCON_DECLARE(uartlite_b, "xlnx,opb-uartlite-1.00.b", early_uartlite_setup);
565 OF_EARLYCON_DECLARE(uartlite_a, "xlnx,xps-uartlite-1.00.a", early_uartlite_setup);
566 
567 #endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
568 
569 static struct uart_driver ulite_uart_driver = {
570 	.owner		= THIS_MODULE,
571 	.driver_name	= "uartlite",
572 	.dev_name	= ULITE_NAME,
573 	.major		= ULITE_MAJOR,
574 	.minor		= ULITE_MINOR,
575 	.nr		= ULITE_NR_UARTS,
576 #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
577 	.cons		= &ulite_console,
578 #endif
579 };
580 
581 /* ---------------------------------------------------------------------
582  * Port assignment functions (mapping devices to uart_port structures)
583  */
584 
585 /** ulite_assign: register a uartlite device with the driver
586  *
587  * @dev: pointer to device structure
588  * @id: requested id number.  Pass -1 for automatic port assignment
589  * @base: base address of uartlite registers
590  * @irq: irq number for uartlite
591  *
592  * Returns: 0 on success, <0 otherwise
593  */
594 static int ulite_assign(struct device *dev, int id, u32 base, int irq)
595 {
596 	struct uart_port *port;
597 	int rc;
598 
599 	/* if id = -1; then scan for a free id and use that */
600 	if (id < 0) {
601 		for (id = 0; id < ULITE_NR_UARTS; id++)
602 			if (ulite_ports[id].mapbase == 0)
603 				break;
604 	}
605 	if (id < 0 || id >= ULITE_NR_UARTS) {
606 		dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
607 		return -EINVAL;
608 	}
609 
610 	if ((ulite_ports[id].mapbase) && (ulite_ports[id].mapbase != base)) {
611 		dev_err(dev, "cannot assign to %s%i; it is already in use\n",
612 			ULITE_NAME, id);
613 		return -EBUSY;
614 	}
615 
616 	port = &ulite_ports[id];
617 
618 	spin_lock_init(&port->lock);
619 	port->fifosize = 16;
620 	port->regshift = 2;
621 	port->iotype = UPIO_MEM;
622 	port->iobase = 1; /* mark port in use */
623 	port->mapbase = base;
624 	port->membase = NULL;
625 	port->ops = &ulite_ops;
626 	port->irq = irq;
627 	port->flags = UPF_BOOT_AUTOCONF;
628 	port->dev = dev;
629 	port->type = PORT_UNKNOWN;
630 	port->line = id;
631 
632 	dev_set_drvdata(dev, port);
633 
634 	/* Register the port */
635 	rc = uart_add_one_port(&ulite_uart_driver, port);
636 	if (rc) {
637 		dev_err(dev, "uart_add_one_port() failed; err=%i\n", rc);
638 		port->mapbase = 0;
639 		dev_set_drvdata(dev, NULL);
640 		return rc;
641 	}
642 
643 	return 0;
644 }
645 
646 /** ulite_release: register a uartlite device with the driver
647  *
648  * @dev: pointer to device structure
649  */
650 static int ulite_release(struct device *dev)
651 {
652 	struct uart_port *port = dev_get_drvdata(dev);
653 	int rc = 0;
654 
655 	if (port) {
656 		rc = uart_remove_one_port(&ulite_uart_driver, port);
657 		dev_set_drvdata(dev, NULL);
658 		port->mapbase = 0;
659 	}
660 
661 	return rc;
662 }
663 
664 /* ---------------------------------------------------------------------
665  * Platform bus binding
666  */
667 
668 #if defined(CONFIG_OF)
669 /* Match table for of_platform binding */
670 static const struct of_device_id ulite_of_match[] = {
671 	{ .compatible = "xlnx,opb-uartlite-1.00.b", },
672 	{ .compatible = "xlnx,xps-uartlite-1.00.a", },
673 	{}
674 };
675 MODULE_DEVICE_TABLE(of, ulite_of_match);
676 #endif /* CONFIG_OF */
677 
678 static int ulite_probe(struct platform_device *pdev)
679 {
680 	struct resource *res;
681 	int irq;
682 	int id = pdev->id;
683 #ifdef CONFIG_OF
684 	const __be32 *prop;
685 
686 	prop = of_get_property(pdev->dev.of_node, "port-number", NULL);
687 	if (prop)
688 		id = be32_to_cpup(prop);
689 #endif
690 
691 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
692 	if (!res)
693 		return -ENODEV;
694 
695 	irq = platform_get_irq(pdev, 0);
696 	if (irq <= 0)
697 		return -ENXIO;
698 
699 	return ulite_assign(&pdev->dev, id, res->start, irq);
700 }
701 
702 static int ulite_remove(struct platform_device *pdev)
703 {
704 	return ulite_release(&pdev->dev);
705 }
706 
707 /* work with hotplug and coldplug */
708 MODULE_ALIAS("platform:uartlite");
709 
710 static struct platform_driver ulite_platform_driver = {
711 	.probe = ulite_probe,
712 	.remove = ulite_remove,
713 	.driver = {
714 		.name  = "uartlite",
715 		.of_match_table = of_match_ptr(ulite_of_match),
716 	},
717 };
718 
719 /* ---------------------------------------------------------------------
720  * Module setup/teardown
721  */
722 
723 static int __init ulite_init(void)
724 {
725 	int ret;
726 
727 	pr_debug("uartlite: calling uart_register_driver()\n");
728 	ret = uart_register_driver(&ulite_uart_driver);
729 	if (ret)
730 		goto err_uart;
731 
732 	pr_debug("uartlite: calling platform_driver_register()\n");
733 	ret = platform_driver_register(&ulite_platform_driver);
734 	if (ret)
735 		goto err_plat;
736 
737 	return 0;
738 
739 err_plat:
740 	uart_unregister_driver(&ulite_uart_driver);
741 err_uart:
742 	pr_err("registering uartlite driver failed: err=%i", ret);
743 	return ret;
744 }
745 
746 static void __exit ulite_exit(void)
747 {
748 	platform_driver_unregister(&ulite_platform_driver);
749 	uart_unregister_driver(&ulite_uart_driver);
750 }
751 
752 module_init(ulite_init);
753 module_exit(ulite_exit);
754 
755 MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
756 MODULE_DESCRIPTION("Xilinx uartlite serial driver");
757 MODULE_LICENSE("GPL");
758