xref: /openbmc/linux/drivers/tty/serial/ar933x_uart.c (revision 588b48ca)
1 /*
2  *  Atheros AR933X SoC built-in UART driver
3  *
4  *  Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
5  *
6  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
7  *
8  *  This program is free software; you can redistribute it and/or modify it
9  *  under the terms of the GNU General Public License version 2 as published
10  *  by the Free Software Foundation.
11  */
12 
13 #include <linux/module.h>
14 #include <linux/ioport.h>
15 #include <linux/init.h>
16 #include <linux/console.h>
17 #include <linux/sysrq.h>
18 #include <linux/delay.h>
19 #include <linux/platform_device.h>
20 #include <linux/of.h>
21 #include <linux/of_platform.h>
22 #include <linux/tty.h>
23 #include <linux/tty_flip.h>
24 #include <linux/serial_core.h>
25 #include <linux/serial.h>
26 #include <linux/slab.h>
27 #include <linux/io.h>
28 #include <linux/irq.h>
29 #include <linux/clk.h>
30 
31 #include <asm/div64.h>
32 
33 #include <asm/mach-ath79/ar933x_uart.h>
34 
35 #define DRIVER_NAME "ar933x-uart"
36 
37 #define AR933X_UART_MAX_SCALE	0xff
38 #define AR933X_UART_MAX_STEP	0xffff
39 
40 #define AR933X_UART_MIN_BAUD	300
41 #define AR933X_UART_MAX_BAUD	3000000
42 
43 #define AR933X_DUMMY_STATUS_RD	0x01
44 
45 static struct uart_driver ar933x_uart_driver;
46 
47 struct ar933x_uart_port {
48 	struct uart_port	port;
49 	unsigned int		ier;	/* shadow Interrupt Enable Register */
50 	unsigned int		min_baud;
51 	unsigned int		max_baud;
52 	struct clk		*clk;
53 };
54 
55 static inline bool ar933x_uart_console_enabled(void)
56 {
57 	return config_enabled(CONFIG_SERIAL_AR933X_CONSOLE);
58 }
59 
60 static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up,
61 					    int offset)
62 {
63 	return readl(up->port.membase + offset);
64 }
65 
66 static inline void ar933x_uart_write(struct ar933x_uart_port *up,
67 				     int offset, unsigned int value)
68 {
69 	writel(value, up->port.membase + offset);
70 }
71 
72 static inline void ar933x_uart_rmw(struct ar933x_uart_port *up,
73 				  unsigned int offset,
74 				  unsigned int mask,
75 				  unsigned int val)
76 {
77 	unsigned int t;
78 
79 	t = ar933x_uart_read(up, offset);
80 	t &= ~mask;
81 	t |= val;
82 	ar933x_uart_write(up, offset, t);
83 }
84 
85 static inline void ar933x_uart_rmw_set(struct ar933x_uart_port *up,
86 				       unsigned int offset,
87 				       unsigned int val)
88 {
89 	ar933x_uart_rmw(up, offset, 0, val);
90 }
91 
92 static inline void ar933x_uart_rmw_clear(struct ar933x_uart_port *up,
93 					 unsigned int offset,
94 					 unsigned int val)
95 {
96 	ar933x_uart_rmw(up, offset, val, 0);
97 }
98 
99 static inline void ar933x_uart_start_tx_interrupt(struct ar933x_uart_port *up)
100 {
101 	up->ier |= AR933X_UART_INT_TX_EMPTY;
102 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
103 }
104 
105 static inline void ar933x_uart_stop_tx_interrupt(struct ar933x_uart_port *up)
106 {
107 	up->ier &= ~AR933X_UART_INT_TX_EMPTY;
108 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
109 }
110 
111 static inline void ar933x_uart_putc(struct ar933x_uart_port *up, int ch)
112 {
113 	unsigned int rdata;
114 
115 	rdata = ch & AR933X_UART_DATA_TX_RX_MASK;
116 	rdata |= AR933X_UART_DATA_TX_CSR;
117 	ar933x_uart_write(up, AR933X_UART_DATA_REG, rdata);
118 }
119 
120 static unsigned int ar933x_uart_tx_empty(struct uart_port *port)
121 {
122 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
123 	unsigned long flags;
124 	unsigned int rdata;
125 
126 	spin_lock_irqsave(&up->port.lock, flags);
127 	rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
128 	spin_unlock_irqrestore(&up->port.lock, flags);
129 
130 	return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT;
131 }
132 
133 static unsigned int ar933x_uart_get_mctrl(struct uart_port *port)
134 {
135 	return TIOCM_CAR;
136 }
137 
138 static void ar933x_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
139 {
140 }
141 
142 static void ar933x_uart_start_tx(struct uart_port *port)
143 {
144 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
145 
146 	ar933x_uart_start_tx_interrupt(up);
147 }
148 
149 static void ar933x_uart_stop_tx(struct uart_port *port)
150 {
151 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
152 
153 	ar933x_uart_stop_tx_interrupt(up);
154 }
155 
156 static void ar933x_uart_stop_rx(struct uart_port *port)
157 {
158 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
159 
160 	up->ier &= ~AR933X_UART_INT_RX_VALID;
161 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
162 }
163 
164 static void ar933x_uart_break_ctl(struct uart_port *port, int break_state)
165 {
166 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
167 	unsigned long flags;
168 
169 	spin_lock_irqsave(&up->port.lock, flags);
170 	if (break_state == -1)
171 		ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
172 				    AR933X_UART_CS_TX_BREAK);
173 	else
174 		ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
175 				      AR933X_UART_CS_TX_BREAK);
176 	spin_unlock_irqrestore(&up->port.lock, flags);
177 }
178 
179 /*
180  * baudrate = (clk / (scale + 1)) * (step * (1 / 2^17))
181  */
182 static unsigned long ar933x_uart_get_baud(unsigned int clk,
183 					  unsigned int scale,
184 					  unsigned int step)
185 {
186 	u64 t;
187 	u32 div;
188 
189 	div = (2 << 16) * (scale + 1);
190 	t = clk;
191 	t *= step;
192 	t += (div / 2);
193 	do_div(t, div);
194 
195 	return t;
196 }
197 
198 static void ar933x_uart_get_scale_step(unsigned int clk,
199 				       unsigned int baud,
200 				       unsigned int *scale,
201 				       unsigned int *step)
202 {
203 	unsigned int tscale;
204 	long min_diff;
205 
206 	*scale = 0;
207 	*step = 0;
208 
209 	min_diff = baud;
210 	for (tscale = 0; tscale < AR933X_UART_MAX_SCALE; tscale++) {
211 		u64 tstep;
212 		int diff;
213 
214 		tstep = baud * (tscale + 1);
215 		tstep *= (2 << 16);
216 		do_div(tstep, clk);
217 
218 		if (tstep > AR933X_UART_MAX_STEP)
219 			break;
220 
221 		diff = abs(ar933x_uart_get_baud(clk, tscale, tstep) - baud);
222 		if (diff < min_diff) {
223 			min_diff = diff;
224 			*scale = tscale;
225 			*step = tstep;
226 		}
227 	}
228 }
229 
230 static void ar933x_uart_set_termios(struct uart_port *port,
231 				    struct ktermios *new,
232 				    struct ktermios *old)
233 {
234 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
235 	unsigned int cs;
236 	unsigned long flags;
237 	unsigned int baud, scale, step;
238 
239 	/* Only CS8 is supported */
240 	new->c_cflag &= ~CSIZE;
241 	new->c_cflag |= CS8;
242 
243 	/* Only one stop bit is supported */
244 	new->c_cflag &= ~CSTOPB;
245 
246 	cs = 0;
247 	if (new->c_cflag & PARENB) {
248 		if (!(new->c_cflag & PARODD))
249 			cs |= AR933X_UART_CS_PARITY_EVEN;
250 		else
251 			cs |= AR933X_UART_CS_PARITY_ODD;
252 	} else {
253 		cs |= AR933X_UART_CS_PARITY_NONE;
254 	}
255 
256 	/* Mark/space parity is not supported */
257 	new->c_cflag &= ~CMSPAR;
258 
259 	baud = uart_get_baud_rate(port, new, old, up->min_baud, up->max_baud);
260 	ar933x_uart_get_scale_step(port->uartclk, baud, &scale, &step);
261 
262 	/*
263 	 * Ok, we're now changing the port state. Do it with
264 	 * interrupts disabled.
265 	 */
266 	spin_lock_irqsave(&up->port.lock, flags);
267 
268 	/* disable the UART */
269 	ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
270 		      AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S);
271 
272 	/* Update the per-port timeout. */
273 	uart_update_timeout(port, new->c_cflag, baud);
274 
275 	up->port.ignore_status_mask = 0;
276 
277 	/* ignore all characters if CREAD is not set */
278 	if ((new->c_cflag & CREAD) == 0)
279 		up->port.ignore_status_mask |= AR933X_DUMMY_STATUS_RD;
280 
281 	ar933x_uart_write(up, AR933X_UART_CLOCK_REG,
282 			  scale << AR933X_UART_CLOCK_SCALE_S | step);
283 
284 	/* setup configuration register */
285 	ar933x_uart_rmw(up, AR933X_UART_CS_REG, AR933X_UART_CS_PARITY_M, cs);
286 
287 	/* enable host interrupt */
288 	ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
289 			    AR933X_UART_CS_HOST_INT_EN);
290 
291 	/* reenable the UART */
292 	ar933x_uart_rmw(up, AR933X_UART_CS_REG,
293 			AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S,
294 			AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S);
295 
296 	spin_unlock_irqrestore(&up->port.lock, flags);
297 
298 	if (tty_termios_baud_rate(new))
299 		tty_termios_encode_baud_rate(new, baud, baud);
300 }
301 
302 static void ar933x_uart_rx_chars(struct ar933x_uart_port *up)
303 {
304 	struct tty_port *port = &up->port.state->port;
305 	int max_count = 256;
306 
307 	do {
308 		unsigned int rdata;
309 		unsigned char ch;
310 
311 		rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
312 		if ((rdata & AR933X_UART_DATA_RX_CSR) == 0)
313 			break;
314 
315 		/* remove the character from the FIFO */
316 		ar933x_uart_write(up, AR933X_UART_DATA_REG,
317 				  AR933X_UART_DATA_RX_CSR);
318 
319 		up->port.icount.rx++;
320 		ch = rdata & AR933X_UART_DATA_TX_RX_MASK;
321 
322 		if (uart_handle_sysrq_char(&up->port, ch))
323 			continue;
324 
325 		if ((up->port.ignore_status_mask & AR933X_DUMMY_STATUS_RD) == 0)
326 			tty_insert_flip_char(port, ch, TTY_NORMAL);
327 	} while (max_count-- > 0);
328 
329 	spin_unlock(&up->port.lock);
330 	tty_flip_buffer_push(port);
331 	spin_lock(&up->port.lock);
332 }
333 
334 static void ar933x_uart_tx_chars(struct ar933x_uart_port *up)
335 {
336 	struct circ_buf *xmit = &up->port.state->xmit;
337 	int count;
338 
339 	if (uart_tx_stopped(&up->port))
340 		return;
341 
342 	count = up->port.fifosize;
343 	do {
344 		unsigned int rdata;
345 
346 		rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
347 		if ((rdata & AR933X_UART_DATA_TX_CSR) == 0)
348 			break;
349 
350 		if (up->port.x_char) {
351 			ar933x_uart_putc(up, up->port.x_char);
352 			up->port.icount.tx++;
353 			up->port.x_char = 0;
354 			continue;
355 		}
356 
357 		if (uart_circ_empty(xmit))
358 			break;
359 
360 		ar933x_uart_putc(up, xmit->buf[xmit->tail]);
361 
362 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
363 		up->port.icount.tx++;
364 	} while (--count > 0);
365 
366 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
367 		uart_write_wakeup(&up->port);
368 
369 	if (!uart_circ_empty(xmit))
370 		ar933x_uart_start_tx_interrupt(up);
371 }
372 
373 static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)
374 {
375 	struct ar933x_uart_port *up = dev_id;
376 	unsigned int status;
377 
378 	status = ar933x_uart_read(up, AR933X_UART_CS_REG);
379 	if ((status & AR933X_UART_CS_HOST_INT) == 0)
380 		return IRQ_NONE;
381 
382 	spin_lock(&up->port.lock);
383 
384 	status = ar933x_uart_read(up, AR933X_UART_INT_REG);
385 	status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
386 
387 	if (status & AR933X_UART_INT_RX_VALID) {
388 		ar933x_uart_write(up, AR933X_UART_INT_REG,
389 				  AR933X_UART_INT_RX_VALID);
390 		ar933x_uart_rx_chars(up);
391 	}
392 
393 	if (status & AR933X_UART_INT_TX_EMPTY) {
394 		ar933x_uart_write(up, AR933X_UART_INT_REG,
395 				  AR933X_UART_INT_TX_EMPTY);
396 		ar933x_uart_stop_tx_interrupt(up);
397 		ar933x_uart_tx_chars(up);
398 	}
399 
400 	spin_unlock(&up->port.lock);
401 
402 	return IRQ_HANDLED;
403 }
404 
405 static int ar933x_uart_startup(struct uart_port *port)
406 {
407 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
408 	unsigned long flags;
409 	int ret;
410 
411 	ret = request_irq(up->port.irq, ar933x_uart_interrupt,
412 			  up->port.irqflags, dev_name(up->port.dev), up);
413 	if (ret)
414 		return ret;
415 
416 	spin_lock_irqsave(&up->port.lock, flags);
417 
418 	/* Enable HOST interrupts */
419 	ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
420 			    AR933X_UART_CS_HOST_INT_EN);
421 
422 	/* Enable RX interrupts */
423 	up->ier = AR933X_UART_INT_RX_VALID;
424 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
425 
426 	spin_unlock_irqrestore(&up->port.lock, flags);
427 
428 	return 0;
429 }
430 
431 static void ar933x_uart_shutdown(struct uart_port *port)
432 {
433 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
434 
435 	/* Disable all interrupts */
436 	up->ier = 0;
437 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
438 
439 	/* Disable break condition */
440 	ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
441 			      AR933X_UART_CS_TX_BREAK);
442 
443 	free_irq(up->port.irq, up);
444 }
445 
446 static const char *ar933x_uart_type(struct uart_port *port)
447 {
448 	return (port->type == PORT_AR933X) ? "AR933X UART" : NULL;
449 }
450 
451 static void ar933x_uart_release_port(struct uart_port *port)
452 {
453 	/* Nothing to release ... */
454 }
455 
456 static int ar933x_uart_request_port(struct uart_port *port)
457 {
458 	/* UARTs always present */
459 	return 0;
460 }
461 
462 static void ar933x_uart_config_port(struct uart_port *port, int flags)
463 {
464 	if (flags & UART_CONFIG_TYPE)
465 		port->type = PORT_AR933X;
466 }
467 
468 static int ar933x_uart_verify_port(struct uart_port *port,
469 				   struct serial_struct *ser)
470 {
471 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
472 
473 	if (ser->type != PORT_UNKNOWN &&
474 	    ser->type != PORT_AR933X)
475 		return -EINVAL;
476 
477 	if (ser->irq < 0 || ser->irq >= NR_IRQS)
478 		return -EINVAL;
479 
480 	if (ser->baud_base < up->min_baud ||
481 	    ser->baud_base > up->max_baud)
482 		return -EINVAL;
483 
484 	return 0;
485 }
486 
487 static struct uart_ops ar933x_uart_ops = {
488 	.tx_empty	= ar933x_uart_tx_empty,
489 	.set_mctrl	= ar933x_uart_set_mctrl,
490 	.get_mctrl	= ar933x_uart_get_mctrl,
491 	.stop_tx	= ar933x_uart_stop_tx,
492 	.start_tx	= ar933x_uart_start_tx,
493 	.stop_rx	= ar933x_uart_stop_rx,
494 	.break_ctl	= ar933x_uart_break_ctl,
495 	.startup	= ar933x_uart_startup,
496 	.shutdown	= ar933x_uart_shutdown,
497 	.set_termios	= ar933x_uart_set_termios,
498 	.type		= ar933x_uart_type,
499 	.release_port	= ar933x_uart_release_port,
500 	.request_port	= ar933x_uart_request_port,
501 	.config_port	= ar933x_uart_config_port,
502 	.verify_port	= ar933x_uart_verify_port,
503 };
504 
505 static struct ar933x_uart_port *
506 ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS];
507 
508 static void ar933x_uart_wait_xmitr(struct ar933x_uart_port *up)
509 {
510 	unsigned int status;
511 	unsigned int timeout = 60000;
512 
513 	/* Wait up to 60ms for the character(s) to be sent. */
514 	do {
515 		status = ar933x_uart_read(up, AR933X_UART_DATA_REG);
516 		if (--timeout == 0)
517 			break;
518 		udelay(1);
519 	} while ((status & AR933X_UART_DATA_TX_CSR) == 0);
520 }
521 
522 static void ar933x_uart_console_putchar(struct uart_port *port, int ch)
523 {
524 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
525 
526 	ar933x_uart_wait_xmitr(up);
527 	ar933x_uart_putc(up, ch);
528 }
529 
530 static void ar933x_uart_console_write(struct console *co, const char *s,
531 				      unsigned int count)
532 {
533 	struct ar933x_uart_port *up = ar933x_console_ports[co->index];
534 	unsigned long flags;
535 	unsigned int int_en;
536 	int locked = 1;
537 
538 	local_irq_save(flags);
539 
540 	if (up->port.sysrq)
541 		locked = 0;
542 	else if (oops_in_progress)
543 		locked = spin_trylock(&up->port.lock);
544 	else
545 		spin_lock(&up->port.lock);
546 
547 	/*
548 	 * First save the IER then disable the interrupts
549 	 */
550 	int_en = ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
551 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, 0);
552 
553 	uart_console_write(&up->port, s, count, ar933x_uart_console_putchar);
554 
555 	/*
556 	 * Finally, wait for transmitter to become empty
557 	 * and restore the IER
558 	 */
559 	ar933x_uart_wait_xmitr(up);
560 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, int_en);
561 
562 	ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS);
563 
564 	if (locked)
565 		spin_unlock(&up->port.lock);
566 
567 	local_irq_restore(flags);
568 }
569 
570 static int ar933x_uart_console_setup(struct console *co, char *options)
571 {
572 	struct ar933x_uart_port *up;
573 	int baud = 115200;
574 	int bits = 8;
575 	int parity = 'n';
576 	int flow = 'n';
577 
578 	if (co->index < 0 || co->index >= CONFIG_SERIAL_AR933X_NR_UARTS)
579 		return -EINVAL;
580 
581 	up = ar933x_console_ports[co->index];
582 	if (!up)
583 		return -ENODEV;
584 
585 	if (options)
586 		uart_parse_options(options, &baud, &parity, &bits, &flow);
587 
588 	return uart_set_options(&up->port, co, baud, parity, bits, flow);
589 }
590 
591 static struct console ar933x_uart_console = {
592 	.name		= "ttyATH",
593 	.write		= ar933x_uart_console_write,
594 	.device		= uart_console_device,
595 	.setup		= ar933x_uart_console_setup,
596 	.flags		= CON_PRINTBUFFER,
597 	.index		= -1,
598 	.data		= &ar933x_uart_driver,
599 };
600 
601 static void ar933x_uart_add_console_port(struct ar933x_uart_port *up)
602 {
603 	if (!ar933x_uart_console_enabled())
604 		return;
605 
606 	ar933x_console_ports[up->port.line] = up;
607 }
608 
609 static struct uart_driver ar933x_uart_driver = {
610 	.owner		= THIS_MODULE,
611 	.driver_name	= DRIVER_NAME,
612 	.dev_name	= "ttyATH",
613 	.nr		= CONFIG_SERIAL_AR933X_NR_UARTS,
614 	.cons		= NULL, /* filled in runtime */
615 };
616 
617 static int ar933x_uart_probe(struct platform_device *pdev)
618 {
619 	struct ar933x_uart_port *up;
620 	struct uart_port *port;
621 	struct resource *mem_res;
622 	struct resource *irq_res;
623 	struct device_node *np;
624 	unsigned int baud;
625 	int id;
626 	int ret;
627 
628 	np = pdev->dev.of_node;
629 	if (config_enabled(CONFIG_OF) && np) {
630 		id = of_alias_get_id(np, "serial");
631 		if (id < 0) {
632 			dev_err(&pdev->dev, "unable to get alias id, err=%d\n",
633 				id);
634 			return id;
635 		}
636 	} else {
637 		id = pdev->id;
638 		if (id == -1)
639 			id = 0;
640 	}
641 
642 	if (id > CONFIG_SERIAL_AR933X_NR_UARTS)
643 		return -EINVAL;
644 
645 	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
646 	if (!irq_res) {
647 		dev_err(&pdev->dev, "no IRQ resource\n");
648 		return -EINVAL;
649 	}
650 
651 	up = devm_kzalloc(&pdev->dev, sizeof(struct ar933x_uart_port),
652 			  GFP_KERNEL);
653 	if (!up)
654 		return -ENOMEM;
655 
656 	up->clk = devm_clk_get(&pdev->dev, "uart");
657 	if (IS_ERR(up->clk)) {
658 		dev_err(&pdev->dev, "unable to get UART clock\n");
659 		return PTR_ERR(up->clk);
660 	}
661 
662 	port = &up->port;
663 
664 	mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
665 	port->membase = devm_ioremap_resource(&pdev->dev, mem_res);
666 	if (IS_ERR(port->membase))
667 		return PTR_ERR(port->membase);
668 
669 	ret = clk_prepare_enable(up->clk);
670 	if (ret)
671 		return ret;
672 
673 	port->uartclk = clk_get_rate(up->clk);
674 	if (!port->uartclk) {
675 		ret = -EINVAL;
676 		goto err_disable_clk;
677 	}
678 
679 	port->mapbase = mem_res->start;
680 	port->line = id;
681 	port->irq = irq_res->start;
682 	port->dev = &pdev->dev;
683 	port->type = PORT_AR933X;
684 	port->iotype = UPIO_MEM32;
685 
686 	port->regshift = 2;
687 	port->fifosize = AR933X_UART_FIFO_SIZE;
688 	port->ops = &ar933x_uart_ops;
689 
690 	baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1);
691 	up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD);
692 
693 	baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP);
694 	up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD);
695 
696 	ar933x_uart_add_console_port(up);
697 
698 	ret = uart_add_one_port(&ar933x_uart_driver, &up->port);
699 	if (ret)
700 		goto err_disable_clk;
701 
702 	platform_set_drvdata(pdev, up);
703 	return 0;
704 
705 err_disable_clk:
706 	clk_disable_unprepare(up->clk);
707 	return ret;
708 }
709 
710 static int ar933x_uart_remove(struct platform_device *pdev)
711 {
712 	struct ar933x_uart_port *up;
713 
714 	up = platform_get_drvdata(pdev);
715 
716 	if (up) {
717 		uart_remove_one_port(&ar933x_uart_driver, &up->port);
718 		clk_disable_unprepare(up->clk);
719 	}
720 
721 	return 0;
722 }
723 
724 #ifdef CONFIG_OF
725 static const struct of_device_id ar933x_uart_of_ids[] = {
726 	{ .compatible = "qca,ar9330-uart" },
727 	{},
728 };
729 MODULE_DEVICE_TABLE(of, ar933x_uart_of_ids);
730 #endif
731 
732 static struct platform_driver ar933x_uart_platform_driver = {
733 	.probe		= ar933x_uart_probe,
734 	.remove		= ar933x_uart_remove,
735 	.driver		= {
736 		.name		= DRIVER_NAME,
737 		.owner		= THIS_MODULE,
738 		.of_match_table = of_match_ptr(ar933x_uart_of_ids),
739 	},
740 };
741 
742 static int __init ar933x_uart_init(void)
743 {
744 	int ret;
745 
746 	if (ar933x_uart_console_enabled())
747 		ar933x_uart_driver.cons = &ar933x_uart_console;
748 
749 	ret = uart_register_driver(&ar933x_uart_driver);
750 	if (ret)
751 		goto err_out;
752 
753 	ret = platform_driver_register(&ar933x_uart_platform_driver);
754 	if (ret)
755 		goto err_unregister_uart_driver;
756 
757 	return 0;
758 
759 err_unregister_uart_driver:
760 	uart_unregister_driver(&ar933x_uart_driver);
761 err_out:
762 	return ret;
763 }
764 
765 static void __exit ar933x_uart_exit(void)
766 {
767 	platform_driver_unregister(&ar933x_uart_platform_driver);
768 	uart_unregister_driver(&ar933x_uart_driver);
769 }
770 
771 module_init(ar933x_uart_init);
772 module_exit(ar933x_uart_exit);
773 
774 MODULE_DESCRIPTION("Atheros AR933X UART driver");
775 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
776 MODULE_LICENSE("GPL v2");
777 MODULE_ALIAS("platform:" DRIVER_NAME);
778