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  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
 45static struct uart_driver ar933x_uart_driver;
 46
 47struct 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
 55static inline bool ar933x_uart_console_enabled(void)
 56{
 57	return IS_ENABLED(CONFIG_SERIAL_AR933X_CONSOLE);
 58}
 59
 60static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up,
 61					    int offset)
 62{
 63	return readl(up->port.membase + offset);
 64}
 65
 66static 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
 72static 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
 85static 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
 92static 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
 99static 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
105static 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
111static 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
120static unsigned int ar933x_uart_tx_empty(struct uart_port *port)
121{
122	struct ar933x_uart_port *up =
123		container_of(port, struct ar933x_uart_port, port);
124	unsigned long flags;
125	unsigned int rdata;
126
127	spin_lock_irqsave(&up->port.lock, flags);
128	rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
129	spin_unlock_irqrestore(&up->port.lock, flags);
130
131	return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT;
132}
133
134static unsigned int ar933x_uart_get_mctrl(struct uart_port *port)
135{
136	return TIOCM_CAR;
137}
138
139static void ar933x_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
140{
141}
142
143static void ar933x_uart_start_tx(struct uart_port *port)
144{
145	struct ar933x_uart_port *up =
146		container_of(port, struct ar933x_uart_port, port);
147
148	ar933x_uart_start_tx_interrupt(up);
149}
150
151static void ar933x_uart_stop_tx(struct uart_port *port)
152{
153	struct ar933x_uart_port *up =
154		container_of(port, struct ar933x_uart_port, port);
155
156	ar933x_uart_stop_tx_interrupt(up);
157}
158
159static void ar933x_uart_stop_rx(struct uart_port *port)
160{
161	struct ar933x_uart_port *up =
162		container_of(port, struct ar933x_uart_port, port);
163
164	up->ier &= ~AR933X_UART_INT_RX_VALID;
165	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
166}
167
168static void ar933x_uart_break_ctl(struct uart_port *port, int break_state)
169{
170	struct ar933x_uart_port *up =
171		container_of(port, struct ar933x_uart_port, port);
172	unsigned long flags;
173
174	spin_lock_irqsave(&up->port.lock, flags);
175	if (break_state == -1)
176		ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
177				    AR933X_UART_CS_TX_BREAK);
178	else
179		ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
180				      AR933X_UART_CS_TX_BREAK);
181	spin_unlock_irqrestore(&up->port.lock, flags);
182}
183
184/*
185 * baudrate = (clk / (scale + 1)) * (step * (1 / 2^17))
186 */
187static unsigned long ar933x_uart_get_baud(unsigned int clk,
188					  unsigned int scale,
189					  unsigned int step)
190{
191	u64 t;
192	u32 div;
193
194	div = (2 << 16) * (scale + 1);
195	t = clk;
196	t *= step;
197	t += (div / 2);
198	do_div(t, div);
199
200	return t;
201}
202
203static void ar933x_uart_get_scale_step(unsigned int clk,
204				       unsigned int baud,
205				       unsigned int *scale,
206				       unsigned int *step)
207{
208	unsigned int tscale;
209	long min_diff;
210
211	*scale = 0;
212	*step = 0;
213
214	min_diff = baud;
215	for (tscale = 0; tscale < AR933X_UART_MAX_SCALE; tscale++) {
216		u64 tstep;
217		int diff;
218
219		tstep = baud * (tscale + 1);
220		tstep *= (2 << 16);
221		do_div(tstep, clk);
222
223		if (tstep > AR933X_UART_MAX_STEP)
224			break;
225
226		diff = abs(ar933x_uart_get_baud(clk, tscale, tstep) - baud);
227		if (diff < min_diff) {
228			min_diff = diff;
229			*scale = tscale;
230			*step = tstep;
231		}
232	}
233}
234
235static void ar933x_uart_set_termios(struct uart_port *port,
236				    struct ktermios *new,
237				    struct ktermios *old)
238{
239	struct ar933x_uart_port *up =
240		container_of(port, struct ar933x_uart_port, port);
241	unsigned int cs;
242	unsigned long flags;
243	unsigned int baud, scale, step;
244
245	/* Only CS8 is supported */
246	new->c_cflag &= ~CSIZE;
247	new->c_cflag |= CS8;
248
249	/* Only one stop bit is supported */
250	new->c_cflag &= ~CSTOPB;
251
252	cs = 0;
253	if (new->c_cflag & PARENB) {
254		if (!(new->c_cflag & PARODD))
255			cs |= AR933X_UART_CS_PARITY_EVEN;
256		else
257			cs |= AR933X_UART_CS_PARITY_ODD;
258	} else {
259		cs |= AR933X_UART_CS_PARITY_NONE;
260	}
261
262	/* Mark/space parity is not supported */
263	new->c_cflag &= ~CMSPAR;
264
265	baud = uart_get_baud_rate(port, new, old, up->min_baud, up->max_baud);
266	ar933x_uart_get_scale_step(port->uartclk, baud, &scale, &step);
267
268	/*
269	 * Ok, we're now changing the port state. Do it with
270	 * interrupts disabled.
271	 */
272	spin_lock_irqsave(&up->port.lock, flags);
273
274	/* disable the UART */
275	ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
276		      AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S);
277
278	/* Update the per-port timeout. */
279	uart_update_timeout(port, new->c_cflag, baud);
280
281	up->port.ignore_status_mask = 0;
282
283	/* ignore all characters if CREAD is not set */
284	if ((new->c_cflag & CREAD) == 0)
285		up->port.ignore_status_mask |= AR933X_DUMMY_STATUS_RD;
286
287	ar933x_uart_write(up, AR933X_UART_CLOCK_REG,
288			  scale << AR933X_UART_CLOCK_SCALE_S | step);
289
290	/* setup configuration register */
291	ar933x_uart_rmw(up, AR933X_UART_CS_REG, AR933X_UART_CS_PARITY_M, cs);
292
293	/* enable host interrupt */
294	ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
295			    AR933X_UART_CS_HOST_INT_EN);
296
297	/* reenable the UART */
298	ar933x_uart_rmw(up, AR933X_UART_CS_REG,
299			AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S,
300			AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S);
301
302	spin_unlock_irqrestore(&up->port.lock, flags);
303
304	if (tty_termios_baud_rate(new))
305		tty_termios_encode_baud_rate(new, baud, baud);
306}
307
308static void ar933x_uart_rx_chars(struct ar933x_uart_port *up)
309{
310	struct tty_port *port = &up->port.state->port;
311	int max_count = 256;
312
313	do {
314		unsigned int rdata;
315		unsigned char ch;
316
317		rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
318		if ((rdata & AR933X_UART_DATA_RX_CSR) == 0)
319			break;
320
321		/* remove the character from the FIFO */
322		ar933x_uart_write(up, AR933X_UART_DATA_REG,
323				  AR933X_UART_DATA_RX_CSR);
324
325		up->port.icount.rx++;
326		ch = rdata & AR933X_UART_DATA_TX_RX_MASK;
327
328		if (uart_handle_sysrq_char(&up->port, ch))
329			continue;
330
331		if ((up->port.ignore_status_mask & AR933X_DUMMY_STATUS_RD) == 0)
332			tty_insert_flip_char(port, ch, TTY_NORMAL);
333	} while (max_count-- > 0);
334
335	spin_unlock(&up->port.lock);
336	tty_flip_buffer_push(port);
337	spin_lock(&up->port.lock);
338}
339
340static void ar933x_uart_tx_chars(struct ar933x_uart_port *up)
341{
342	struct circ_buf *xmit = &up->port.state->xmit;
343	int count;
344
345	if (uart_tx_stopped(&up->port))
346		return;
347
348	count = up->port.fifosize;
349	do {
350		unsigned int rdata;
351
352		rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
353		if ((rdata & AR933X_UART_DATA_TX_CSR) == 0)
354			break;
355
356		if (up->port.x_char) {
357			ar933x_uart_putc(up, up->port.x_char);
358			up->port.icount.tx++;
359			up->port.x_char = 0;
360			continue;
361		}
362
363		if (uart_circ_empty(xmit))
364			break;
365
366		ar933x_uart_putc(up, xmit->buf[xmit->tail]);
367
368		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
369		up->port.icount.tx++;
370	} while (--count > 0);
371
372	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
373		uart_write_wakeup(&up->port);
374
375	if (!uart_circ_empty(xmit))
376		ar933x_uart_start_tx_interrupt(up);
377}
378
379static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)
380{
381	struct ar933x_uart_port *up = dev_id;
382	unsigned int status;
383
384	status = ar933x_uart_read(up, AR933X_UART_CS_REG);
385	if ((status & AR933X_UART_CS_HOST_INT) == 0)
386		return IRQ_NONE;
387
388	spin_lock(&up->port.lock);
389
390	status = ar933x_uart_read(up, AR933X_UART_INT_REG);
391	status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
392
393	if (status & AR933X_UART_INT_RX_VALID) {
394		ar933x_uart_write(up, AR933X_UART_INT_REG,
395				  AR933X_UART_INT_RX_VALID);
396		ar933x_uart_rx_chars(up);
397	}
398
399	if (status & AR933X_UART_INT_TX_EMPTY) {
400		ar933x_uart_write(up, AR933X_UART_INT_REG,
401				  AR933X_UART_INT_TX_EMPTY);
402		ar933x_uart_stop_tx_interrupt(up);
403		ar933x_uart_tx_chars(up);
404	}
405
406	spin_unlock(&up->port.lock);
407
408	return IRQ_HANDLED;
409}
410
411static int ar933x_uart_startup(struct uart_port *port)
412{
413	struct ar933x_uart_port *up =
414		container_of(port, struct ar933x_uart_port, port);
415	unsigned long flags;
416	int ret;
417
418	ret = request_irq(up->port.irq, ar933x_uart_interrupt,
419			  up->port.irqflags, dev_name(up->port.dev), up);
420	if (ret)
421		return ret;
422
423	spin_lock_irqsave(&up->port.lock, flags);
424
425	/* Enable HOST interrupts */
426	ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
427			    AR933X_UART_CS_HOST_INT_EN);
428
429	/* Enable RX interrupts */
430	up->ier = AR933X_UART_INT_RX_VALID;
431	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
432
433	spin_unlock_irqrestore(&up->port.lock, flags);
434
435	return 0;
436}
437
438static void ar933x_uart_shutdown(struct uart_port *port)
439{
440	struct ar933x_uart_port *up =
441		container_of(port, struct ar933x_uart_port, port);
442
443	/* Disable all interrupts */
444	up->ier = 0;
445	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
446
447	/* Disable break condition */
448	ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
449			      AR933X_UART_CS_TX_BREAK);
450
451	free_irq(up->port.irq, up);
452}
453
454static const char *ar933x_uart_type(struct uart_port *port)
455{
456	return (port->type == PORT_AR933X) ? "AR933X UART" : NULL;
457}
458
459static void ar933x_uart_release_port(struct uart_port *port)
460{
461	/* Nothing to release ... */
462}
463
464static int ar933x_uart_request_port(struct uart_port *port)
465{
466	/* UARTs always present */
467	return 0;
468}
469
470static void ar933x_uart_config_port(struct uart_port *port, int flags)
471{
472	if (flags & UART_CONFIG_TYPE)
473		port->type = PORT_AR933X;
474}
475
476static int ar933x_uart_verify_port(struct uart_port *port,
477				   struct serial_struct *ser)
478{
479	struct ar933x_uart_port *up =
480		container_of(port, struct ar933x_uart_port, port);
481
482	if (ser->type != PORT_UNKNOWN &&
483	    ser->type != PORT_AR933X)
484		return -EINVAL;
485
486	if (ser->irq < 0 || ser->irq >= NR_IRQS)
487		return -EINVAL;
488
489	if (ser->baud_base < up->min_baud ||
490	    ser->baud_base > up->max_baud)
491		return -EINVAL;
492
493	return 0;
494}
495
496static struct uart_ops ar933x_uart_ops = {
497	.tx_empty	= ar933x_uart_tx_empty,
498	.set_mctrl	= ar933x_uart_set_mctrl,
499	.get_mctrl	= ar933x_uart_get_mctrl,
500	.stop_tx	= ar933x_uart_stop_tx,
501	.start_tx	= ar933x_uart_start_tx,
502	.stop_rx	= ar933x_uart_stop_rx,
503	.break_ctl	= ar933x_uart_break_ctl,
504	.startup	= ar933x_uart_startup,
505	.shutdown	= ar933x_uart_shutdown,
506	.set_termios	= ar933x_uart_set_termios,
507	.type		= ar933x_uart_type,
508	.release_port	= ar933x_uart_release_port,
509	.request_port	= ar933x_uart_request_port,
510	.config_port	= ar933x_uart_config_port,
511	.verify_port	= ar933x_uart_verify_port,
512};
513
514static struct ar933x_uart_port *
515ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS];
516
517static void ar933x_uart_wait_xmitr(struct ar933x_uart_port *up)
518{
519	unsigned int status;
520	unsigned int timeout = 60000;
521
522	/* Wait up to 60ms for the character(s) to be sent. */
523	do {
524		status = ar933x_uart_read(up, AR933X_UART_DATA_REG);
525		if (--timeout == 0)
526			break;
527		udelay(1);
528	} while ((status & AR933X_UART_DATA_TX_CSR) == 0);
529}
530
531static void ar933x_uart_console_putchar(struct uart_port *port, int ch)
532{
533	struct ar933x_uart_port *up =
534		container_of(port, struct ar933x_uart_port, port);
535
536	ar933x_uart_wait_xmitr(up);
537	ar933x_uart_putc(up, ch);
538}
539
540static void ar933x_uart_console_write(struct console *co, const char *s,
541				      unsigned int count)
542{
543	struct ar933x_uart_port *up = ar933x_console_ports[co->index];
544	unsigned long flags;
545	unsigned int int_en;
546	int locked = 1;
547
548	local_irq_save(flags);
549
550	if (up->port.sysrq)
551		locked = 0;
552	else if (oops_in_progress)
553		locked = spin_trylock(&up->port.lock);
554	else
555		spin_lock(&up->port.lock);
556
557	/*
558	 * First save the IER then disable the interrupts
559	 */
560	int_en = ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
561	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, 0);
562
563	uart_console_write(&up->port, s, count, ar933x_uart_console_putchar);
564
565	/*
566	 * Finally, wait for transmitter to become empty
567	 * and restore the IER
568	 */
569	ar933x_uart_wait_xmitr(up);
570	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, int_en);
571
572	ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS);
573
574	if (locked)
575		spin_unlock(&up->port.lock);
576
577	local_irq_restore(flags);
578}
579
580static int ar933x_uart_console_setup(struct console *co, char *options)
581{
582	struct ar933x_uart_port *up;
583	int baud = 115200;
584	int bits = 8;
585	int parity = 'n';
586	int flow = 'n';
587
588	if (co->index < 0 || co->index >= CONFIG_SERIAL_AR933X_NR_UARTS)
589		return -EINVAL;
590
591	up = ar933x_console_ports[co->index];
592	if (!up)
593		return -ENODEV;
594
595	if (options)
596		uart_parse_options(options, &baud, &parity, &bits, &flow);
597
598	return uart_set_options(&up->port, co, baud, parity, bits, flow);
599}
600
601static struct console ar933x_uart_console = {
602	.name		= "ttyATH",
603	.write		= ar933x_uart_console_write,
604	.device		= uart_console_device,
605	.setup		= ar933x_uart_console_setup,
606	.flags		= CON_PRINTBUFFER,
607	.index		= -1,
608	.data		= &ar933x_uart_driver,
609};
610
611static void ar933x_uart_add_console_port(struct ar933x_uart_port *up)
612{
613	if (!ar933x_uart_console_enabled())
614		return;
615
616	ar933x_console_ports[up->port.line] = up;
617}
618
619static struct uart_driver ar933x_uart_driver = {
620	.owner		= THIS_MODULE,
621	.driver_name	= DRIVER_NAME,
622	.dev_name	= "ttyATH",
623	.nr		= CONFIG_SERIAL_AR933X_NR_UARTS,
624	.cons		= NULL, /* filled in runtime */
625};
626
627static int ar933x_uart_probe(struct platform_device *pdev)
628{
629	struct ar933x_uart_port *up;
630	struct uart_port *port;
631	struct resource *mem_res;
632	struct resource *irq_res;
633	struct device_node *np;
634	unsigned int baud;
635	int id;
636	int ret;
637
638	np = pdev->dev.of_node;
639	if (IS_ENABLED(CONFIG_OF) && np) {
640		id = of_alias_get_id(np, "serial");
641		if (id < 0) {
642			dev_err(&pdev->dev, "unable to get alias id, err=%d\n",
643				id);
644			return id;
645		}
646	} else {
647		id = pdev->id;
648		if (id == -1)
649			id = 0;
650	}
651
652	if (id >= CONFIG_SERIAL_AR933X_NR_UARTS)
653		return -EINVAL;
654
655	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
656	if (!irq_res) {
657		dev_err(&pdev->dev, "no IRQ resource\n");
658		return -EINVAL;
659	}
660
661	up = devm_kzalloc(&pdev->dev, sizeof(struct ar933x_uart_port),
662			  GFP_KERNEL);
663	if (!up)
664		return -ENOMEM;
665
666	up->clk = devm_clk_get(&pdev->dev, "uart");
667	if (IS_ERR(up->clk)) {
668		dev_err(&pdev->dev, "unable to get UART clock\n");
669		return PTR_ERR(up->clk);
670	}
671
672	port = &up->port;
673
674	mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
675	port->membase = devm_ioremap_resource(&pdev->dev, mem_res);
676	if (IS_ERR(port->membase))
677		return PTR_ERR(port->membase);
678
679	ret = clk_prepare_enable(up->clk);
680	if (ret)
681		return ret;
682
683	port->uartclk = clk_get_rate(up->clk);
684	if (!port->uartclk) {
685		ret = -EINVAL;
686		goto err_disable_clk;
687	}
688
689	port->mapbase = mem_res->start;
690	port->line = id;
691	port->irq = irq_res->start;
692	port->dev = &pdev->dev;
693	port->type = PORT_AR933X;
694	port->iotype = UPIO_MEM32;
695
696	port->regshift = 2;
697	port->fifosize = AR933X_UART_FIFO_SIZE;
698	port->ops = &ar933x_uart_ops;
699
700	baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1);
701	up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD);
702
703	baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP);
704	up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD);
705
706	ar933x_uart_add_console_port(up);
707
708	ret = uart_add_one_port(&ar933x_uart_driver, &up->port);
709	if (ret)
710		goto err_disable_clk;
711
712	platform_set_drvdata(pdev, up);
713	return 0;
714
715err_disable_clk:
716	clk_disable_unprepare(up->clk);
717	return ret;
718}
719
720static int ar933x_uart_remove(struct platform_device *pdev)
721{
722	struct ar933x_uart_port *up;
723
724	up = platform_get_drvdata(pdev);
725
726	if (up) {
727		uart_remove_one_port(&ar933x_uart_driver, &up->port);
728		clk_disable_unprepare(up->clk);
729	}
730
731	return 0;
732}
733
734#ifdef CONFIG_OF
735static const struct of_device_id ar933x_uart_of_ids[] = {
736	{ .compatible = "qca,ar9330-uart" },
737	{},
738};
739MODULE_DEVICE_TABLE(of, ar933x_uart_of_ids);
740#endif
741
742static struct platform_driver ar933x_uart_platform_driver = {
743	.probe		= ar933x_uart_probe,
744	.remove		= ar933x_uart_remove,
745	.driver		= {
746		.name		= DRIVER_NAME,
747		.of_match_table = of_match_ptr(ar933x_uart_of_ids),
748	},
749};
750
751static int __init ar933x_uart_init(void)
752{
753	int ret;
754
755	if (ar933x_uart_console_enabled())
756		ar933x_uart_driver.cons = &ar933x_uart_console;
757
758	ret = uart_register_driver(&ar933x_uart_driver);
759	if (ret)
760		goto err_out;
761
762	ret = platform_driver_register(&ar933x_uart_platform_driver);
763	if (ret)
764		goto err_unregister_uart_driver;
765
766	return 0;
767
768err_unregister_uart_driver:
769	uart_unregister_driver(&ar933x_uart_driver);
770err_out:
771	return ret;
772}
773
774static void __exit ar933x_uart_exit(void)
775{
776	platform_driver_unregister(&ar933x_uart_platform_driver);
777	uart_unregister_driver(&ar933x_uart_driver);
778}
779
780module_init(ar933x_uart_init);
781module_exit(ar933x_uart_exit);
782
783MODULE_DESCRIPTION("Atheros AR933X UART driver");
784MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
785MODULE_LICENSE("GPL v2");
786MODULE_ALIAS("platform:" DRIVER_NAME);