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  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Actions Semi Owl family serial console
  4 *
  5 * Copyright 2013 Actions Semi Inc.
  6 * Author: Actions Semi, Inc.
  7 *
  8 * Copyright (c) 2016-2017 Andreas Färber
  9 */
 10
 11#include <linux/clk.h>
 12#include <linux/console.h>
 13#include <linux/delay.h>
 14#include <linux/io.h>
 15#include <linux/iopoll.h>
 16#include <linux/module.h>
 17#include <linux/of.h>
 18#include <linux/platform_device.h>
 19#include <linux/serial.h>
 20#include <linux/serial_core.h>
 21#include <linux/tty.h>
 22#include <linux/tty_flip.h>
 23
 24#define OWL_UART_PORT_NUM 7
 25#define OWL_UART_DEV_NAME "ttyOWL"
 26
 27#define OWL_UART_CTL	0x000
 28#define OWL_UART_RXDAT	0x004
 29#define OWL_UART_TXDAT	0x008
 30#define OWL_UART_STAT	0x00c
 31
 32#define OWL_UART_CTL_DWLS_MASK		GENMASK(1, 0)
 33#define OWL_UART_CTL_DWLS_5BITS		(0x0 << 0)
 34#define OWL_UART_CTL_DWLS_6BITS		(0x1 << 0)
 35#define OWL_UART_CTL_DWLS_7BITS		(0x2 << 0)
 36#define OWL_UART_CTL_DWLS_8BITS		(0x3 << 0)
 37#define OWL_UART_CTL_STPS_2BITS		BIT(2)
 38#define OWL_UART_CTL_PRS_MASK		GENMASK(6, 4)
 39#define OWL_UART_CTL_PRS_NONE		(0x0 << 4)
 40#define OWL_UART_CTL_PRS_ODD		(0x4 << 4)
 41#define OWL_UART_CTL_PRS_MARK		(0x5 << 4)
 42#define OWL_UART_CTL_PRS_EVEN		(0x6 << 4)
 43#define OWL_UART_CTL_PRS_SPACE		(0x7 << 4)
 44#define OWL_UART_CTL_AFE		BIT(12)
 45#define OWL_UART_CTL_TRFS_TX		BIT(14)
 46#define OWL_UART_CTL_EN			BIT(15)
 47#define OWL_UART_CTL_RXDE		BIT(16)
 48#define OWL_UART_CTL_TXDE		BIT(17)
 49#define OWL_UART_CTL_RXIE		BIT(18)
 50#define OWL_UART_CTL_TXIE		BIT(19)
 51#define OWL_UART_CTL_LBEN		BIT(20)
 52
 53#define OWL_UART_STAT_RIP		BIT(0)
 54#define OWL_UART_STAT_TIP		BIT(1)
 55#define OWL_UART_STAT_RXER		BIT(2)
 56#define OWL_UART_STAT_TFER		BIT(3)
 57#define OWL_UART_STAT_RXST		BIT(4)
 58#define OWL_UART_STAT_RFEM		BIT(5)
 59#define OWL_UART_STAT_TFFU		BIT(6)
 60#define OWL_UART_STAT_CTSS		BIT(7)
 61#define OWL_UART_STAT_RTSS		BIT(8)
 62#define OWL_UART_STAT_TFES		BIT(10)
 63#define OWL_UART_STAT_TRFL_MASK		GENMASK(16, 11)
 64#define OWL_UART_STAT_UTBB		BIT(17)
 65
 66#define OWL_UART_POLL_USEC		5
 67#define OWL_UART_TIMEOUT_USEC		10000
 68
 69static struct uart_driver owl_uart_driver;
 70
 71struct owl_uart_info {
 72	unsigned int tx_fifosize;
 73};
 74
 75struct owl_uart_port {
 76	struct uart_port port;
 77	struct clk *clk;
 78};
 79
 80#define to_owl_uart_port(prt) container_of(prt, struct owl_uart_port, prt)
 81
 82static struct owl_uart_port *owl_uart_ports[OWL_UART_PORT_NUM];
 83
 84static inline void owl_uart_write(struct uart_port *port, u32 val, unsigned int off)
 85{
 86	writel(val, port->membase + off);
 87}
 88
 89static inline u32 owl_uart_read(struct uart_port *port, unsigned int off)
 90{
 91	return readl(port->membase + off);
 92}
 93
 94static void owl_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 95{
 96	u32 ctl;
 97
 98	ctl = owl_uart_read(port, OWL_UART_CTL);
 99
100	if (mctrl & TIOCM_LOOP)
101		ctl |= OWL_UART_CTL_LBEN;
102	else
103		ctl &= ~OWL_UART_CTL_LBEN;
104
105	owl_uart_write(port, ctl, OWL_UART_CTL);
106}
107
108static unsigned int owl_uart_get_mctrl(struct uart_port *port)
109{
110	unsigned int mctrl = TIOCM_CAR | TIOCM_DSR;
111	u32 stat, ctl;
112
113	ctl = owl_uart_read(port, OWL_UART_CTL);
114	stat = owl_uart_read(port, OWL_UART_STAT);
115	if (stat & OWL_UART_STAT_RTSS)
116		mctrl |= TIOCM_RTS;
117	if ((stat & OWL_UART_STAT_CTSS) || !(ctl & OWL_UART_CTL_AFE))
118		mctrl |= TIOCM_CTS;
119	return mctrl;
120}
121
122static unsigned int owl_uart_tx_empty(struct uart_port *port)
123{
124	unsigned long flags;
125	u32 val;
126	unsigned int ret;
127
128	uart_port_lock_irqsave(port, &flags);
129
130	val = owl_uart_read(port, OWL_UART_STAT);
131	ret = (val & OWL_UART_STAT_TFES) ? TIOCSER_TEMT : 0;
132
133	uart_port_unlock_irqrestore(port, flags);
134
135	return ret;
136}
137
138static void owl_uart_stop_rx(struct uart_port *port)
139{
140	u32 val;
141
142	val = owl_uart_read(port, OWL_UART_CTL);
143	val &= ~(OWL_UART_CTL_RXIE | OWL_UART_CTL_RXDE);
144	owl_uart_write(port, val, OWL_UART_CTL);
145
146	val = owl_uart_read(port, OWL_UART_STAT);
147	val |= OWL_UART_STAT_RIP;
148	owl_uart_write(port, val, OWL_UART_STAT);
149}
150
151static void owl_uart_stop_tx(struct uart_port *port)
152{
153	u32 val;
154
155	val = owl_uart_read(port, OWL_UART_CTL);
156	val &= ~(OWL_UART_CTL_TXIE | OWL_UART_CTL_TXDE);
157	owl_uart_write(port, val, OWL_UART_CTL);
158
159	val = owl_uart_read(port, OWL_UART_STAT);
160	val |= OWL_UART_STAT_TIP;
161	owl_uart_write(port, val, OWL_UART_STAT);
162}
163
164static void owl_uart_start_tx(struct uart_port *port)
165{
166	u32 val;
167
168	if (uart_tx_stopped(port)) {
169		owl_uart_stop_tx(port);
170		return;
171	}
172
173	val = owl_uart_read(port, OWL_UART_STAT);
174	val |= OWL_UART_STAT_TIP;
175	owl_uart_write(port, val, OWL_UART_STAT);
176
177	val = owl_uart_read(port, OWL_UART_CTL);
178	val |= OWL_UART_CTL_TXIE;
179	owl_uart_write(port, val, OWL_UART_CTL);
180}
181
182static void owl_uart_send_chars(struct uart_port *port)
183{
184	u8 ch;
185
186	uart_port_tx(port, ch,
187		!(owl_uart_read(port, OWL_UART_STAT) & OWL_UART_STAT_TFFU),
188		owl_uart_write(port, ch, OWL_UART_TXDAT));
189}
190
191static void owl_uart_receive_chars(struct uart_port *port)
192{
193	u32 stat, val;
194
195	val = owl_uart_read(port, OWL_UART_CTL);
196	val &= ~OWL_UART_CTL_TRFS_TX;
197	owl_uart_write(port, val, OWL_UART_CTL);
198
199	stat = owl_uart_read(port, OWL_UART_STAT);
200	while (!(stat & OWL_UART_STAT_RFEM)) {
201		char flag = TTY_NORMAL;
202
203		if (stat & OWL_UART_STAT_RXER)
204			port->icount.overrun++;
205
206		if (stat & OWL_UART_STAT_RXST) {
207			/* We are not able to distinguish the error type. */
208			port->icount.brk++;
209			port->icount.frame++;
210
211			stat &= port->read_status_mask;
212			if (stat & OWL_UART_STAT_RXST)
213				flag = TTY_PARITY;
214		} else
215			port->icount.rx++;
216
217		val = owl_uart_read(port, OWL_UART_RXDAT);
218		val &= 0xff;
219
220		if ((stat & port->ignore_status_mask) == 0)
221			tty_insert_flip_char(&port->state->port, val, flag);
222
223		stat = owl_uart_read(port, OWL_UART_STAT);
224	}
225
226	tty_flip_buffer_push(&port->state->port);
227}
228
229static irqreturn_t owl_uart_irq(int irq, void *dev_id)
230{
231	struct uart_port *port = dev_id;
232	unsigned long flags;
233	u32 stat;
234
235	uart_port_lock_irqsave(port, &flags);
236
237	stat = owl_uart_read(port, OWL_UART_STAT);
238
239	if (stat & OWL_UART_STAT_RIP)
240		owl_uart_receive_chars(port);
241
242	if (stat & OWL_UART_STAT_TIP)
243		owl_uart_send_chars(port);
244
245	stat = owl_uart_read(port, OWL_UART_STAT);
246	stat |= OWL_UART_STAT_RIP | OWL_UART_STAT_TIP;
247	owl_uart_write(port, stat, OWL_UART_STAT);
248
249	uart_port_unlock_irqrestore(port, flags);
250
251	return IRQ_HANDLED;
252}
253
254static void owl_uart_shutdown(struct uart_port *port)
255{
256	u32 val;
257	unsigned long flags;
258
259	uart_port_lock_irqsave(port, &flags);
260
261	val = owl_uart_read(port, OWL_UART_CTL);
262	val &= ~(OWL_UART_CTL_TXIE | OWL_UART_CTL_RXIE
263		| OWL_UART_CTL_TXDE | OWL_UART_CTL_RXDE | OWL_UART_CTL_EN);
264	owl_uart_write(port, val, OWL_UART_CTL);
265
266	uart_port_unlock_irqrestore(port, flags);
267
268	free_irq(port->irq, port);
269}
270
271static int owl_uart_startup(struct uart_port *port)
272{
273	u32 val;
274	unsigned long flags;
275	int ret;
276
277	ret = request_irq(port->irq, owl_uart_irq, IRQF_TRIGGER_HIGH,
278			"owl-uart", port);
279	if (ret)
280		return ret;
281
282	uart_port_lock_irqsave(port, &flags);
283
284	val = owl_uart_read(port, OWL_UART_STAT);
285	val |= OWL_UART_STAT_RIP | OWL_UART_STAT_TIP
286		| OWL_UART_STAT_RXER | OWL_UART_STAT_TFER | OWL_UART_STAT_RXST;
287	owl_uart_write(port, val, OWL_UART_STAT);
288
289	val = owl_uart_read(port, OWL_UART_CTL);
290	val |= OWL_UART_CTL_RXIE | OWL_UART_CTL_TXIE;
291	val |= OWL_UART_CTL_EN;
292	owl_uart_write(port, val, OWL_UART_CTL);
293
294	uart_port_unlock_irqrestore(port, flags);
295
296	return 0;
297}
298
299static void owl_uart_change_baudrate(struct owl_uart_port *owl_port,
300				     unsigned long baud)
301{
302	clk_set_rate(owl_port->clk, baud * 8);
303}
304
305static void owl_uart_set_termios(struct uart_port *port,
306				 struct ktermios *termios,
307				 const struct ktermios *old)
308{
309	struct owl_uart_port *owl_port = to_owl_uart_port(port);
310	unsigned int baud;
311	u32 ctl;
312	unsigned long flags;
313
314	uart_port_lock_irqsave(port, &flags);
315
316	ctl = owl_uart_read(port, OWL_UART_CTL);
317
318	ctl &= ~OWL_UART_CTL_DWLS_MASK;
319	switch (termios->c_cflag & CSIZE) {
320	case CS5:
321		ctl |= OWL_UART_CTL_DWLS_5BITS;
322		break;
323	case CS6:
324		ctl |= OWL_UART_CTL_DWLS_6BITS;
325		break;
326	case CS7:
327		ctl |= OWL_UART_CTL_DWLS_7BITS;
328		break;
329	case CS8:
330	default:
331		ctl |= OWL_UART_CTL_DWLS_8BITS;
332		break;
333	}
334
335	if (termios->c_cflag & CSTOPB)
336		ctl |= OWL_UART_CTL_STPS_2BITS;
337	else
338		ctl &= ~OWL_UART_CTL_STPS_2BITS;
339
340	ctl &= ~OWL_UART_CTL_PRS_MASK;
341	if (termios->c_cflag & PARENB) {
342		if (termios->c_cflag & CMSPAR) {
343			if (termios->c_cflag & PARODD)
344				ctl |= OWL_UART_CTL_PRS_MARK;
345			else
346				ctl |= OWL_UART_CTL_PRS_SPACE;
347		} else if (termios->c_cflag & PARODD)
348			ctl |= OWL_UART_CTL_PRS_ODD;
349		else
350			ctl |= OWL_UART_CTL_PRS_EVEN;
351	} else
352		ctl |= OWL_UART_CTL_PRS_NONE;
353
354	if (termios->c_cflag & CRTSCTS)
355		ctl |= OWL_UART_CTL_AFE;
356	else
357		ctl &= ~OWL_UART_CTL_AFE;
358
359	owl_uart_write(port, ctl, OWL_UART_CTL);
360
361	baud = uart_get_baud_rate(port, termios, old, 9600, 3200000);
362	owl_uart_change_baudrate(owl_port, baud);
363
364	/* Don't rewrite B0 */
365	if (tty_termios_baud_rate(termios))
366		tty_termios_encode_baud_rate(termios, baud, baud);
367
368	port->read_status_mask |= OWL_UART_STAT_RXER;
369	if (termios->c_iflag & INPCK)
370		port->read_status_mask |= OWL_UART_STAT_RXST;
371
372	uart_update_timeout(port, termios->c_cflag, baud);
373
374	uart_port_unlock_irqrestore(port, flags);
375}
376
377static void owl_uart_release_port(struct uart_port *port)
378{
379	struct platform_device *pdev = to_platform_device(port->dev);
380	struct resource *res;
381
382	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
383	if (!res)
384		return;
385
386	if (port->flags & UPF_IOREMAP) {
387		devm_release_mem_region(port->dev, port->mapbase,
388			resource_size(res));
389		devm_iounmap(port->dev, port->membase);
390		port->membase = NULL;
391	}
392}
393
394static int owl_uart_request_port(struct uart_port *port)
395{
396	struct platform_device *pdev = to_platform_device(port->dev);
397	struct resource *res;
398
399	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
400	if (!res)
401		return -ENXIO;
402
403	if (!devm_request_mem_region(port->dev, port->mapbase,
404			resource_size(res), dev_name(port->dev)))
405		return -EBUSY;
406
407	if (port->flags & UPF_IOREMAP) {
408		port->membase = devm_ioremap(port->dev, port->mapbase,
409				resource_size(res));
410		if (!port->membase)
411			return -EBUSY;
412	}
413
414	return 0;
415}
416
417static const char *owl_uart_type(struct uart_port *port)
418{
419	return (port->type == PORT_OWL) ? "owl-uart" : NULL;
420}
421
422static int owl_uart_verify_port(struct uart_port *port,
423				struct serial_struct *ser)
424{
425	if (port->type != PORT_OWL)
426		return -EINVAL;
427
428	if (port->irq != ser->irq)
429		return -EINVAL;
430
431	return 0;
432}
433
434static void owl_uart_config_port(struct uart_port *port, int flags)
435{
436	if (flags & UART_CONFIG_TYPE) {
437		port->type = PORT_OWL;
438		owl_uart_request_port(port);
439	}
440}
441
442#ifdef CONFIG_CONSOLE_POLL
443
444static int owl_uart_poll_get_char(struct uart_port *port)
445{
446	if (owl_uart_read(port, OWL_UART_STAT) & OWL_UART_STAT_RFEM)
447		return NO_POLL_CHAR;
448
449	return owl_uart_read(port, OWL_UART_RXDAT);
450}
451
452static void owl_uart_poll_put_char(struct uart_port *port, unsigned char ch)
453{
454	u32 reg;
455	int ret;
456
457	/* Wait while FIFO is full or timeout */
458	ret = readl_poll_timeout_atomic(port->membase + OWL_UART_STAT, reg,
459					!(reg & OWL_UART_STAT_TFFU),
460					OWL_UART_POLL_USEC,
461					OWL_UART_TIMEOUT_USEC);
462	if (ret == -ETIMEDOUT) {
463		dev_err(port->dev, "Timeout waiting while UART TX FULL\n");
464		return;
465	}
466
467	owl_uart_write(port, ch, OWL_UART_TXDAT);
468}
469
470#endif /* CONFIG_CONSOLE_POLL */
471
472static const struct uart_ops owl_uart_ops = {
473	.set_mctrl = owl_uart_set_mctrl,
474	.get_mctrl = owl_uart_get_mctrl,
475	.tx_empty = owl_uart_tx_empty,
476	.start_tx = owl_uart_start_tx,
477	.stop_rx = owl_uart_stop_rx,
478	.stop_tx = owl_uart_stop_tx,
479	.startup = owl_uart_startup,
480	.shutdown = owl_uart_shutdown,
481	.set_termios = owl_uart_set_termios,
482	.type = owl_uart_type,
483	.config_port = owl_uart_config_port,
484	.request_port = owl_uart_request_port,
485	.release_port = owl_uart_release_port,
486	.verify_port = owl_uart_verify_port,
487#ifdef CONFIG_CONSOLE_POLL
488	.poll_get_char = owl_uart_poll_get_char,
489	.poll_put_char = owl_uart_poll_put_char,
490#endif
491};
492
493#ifdef CONFIG_SERIAL_OWL_CONSOLE
494
495static void owl_console_putchar(struct uart_port *port, unsigned char ch)
496{
497	if (!port->membase)
498		return;
499
500	while (owl_uart_read(port, OWL_UART_STAT) & OWL_UART_STAT_TFFU)
501		cpu_relax();
502
503	owl_uart_write(port, ch, OWL_UART_TXDAT);
504}
505
506static void owl_uart_port_write(struct uart_port *port, const char *s,
507				u_int count)
508{
509	u32 old_ctl, val;
510	unsigned long flags;
511	int locked;
512
513	local_irq_save(flags);
514
515	if (port->sysrq)
516		locked = 0;
517	else if (oops_in_progress)
518		locked = uart_port_trylock(port);
519	else {
520		uart_port_lock(port);
521		locked = 1;
522	}
523
524	old_ctl = owl_uart_read(port, OWL_UART_CTL);
525	val = old_ctl | OWL_UART_CTL_TRFS_TX;
526	/* disable IRQ */
527	val &= ~(OWL_UART_CTL_RXIE | OWL_UART_CTL_TXIE);
528	owl_uart_write(port, val, OWL_UART_CTL);
529
530	uart_console_write(port, s, count, owl_console_putchar);
531
532	/* wait until all contents have been sent out */
533	while (owl_uart_read(port, OWL_UART_STAT) & OWL_UART_STAT_TRFL_MASK)
534		cpu_relax();
535
536	/* clear IRQ pending */
537	val = owl_uart_read(port, OWL_UART_STAT);
538	val |= OWL_UART_STAT_TIP | OWL_UART_STAT_RIP;
539	owl_uart_write(port, val, OWL_UART_STAT);
540
541	owl_uart_write(port, old_ctl, OWL_UART_CTL);
542
543	if (locked)
544		uart_port_unlock(port);
545
546	local_irq_restore(flags);
547}
548
549static void owl_uart_console_write(struct console *co, const char *s,
550				   u_int count)
551{
552	struct owl_uart_port *owl_port;
553
554	owl_port = owl_uart_ports[co->index];
555	if (!owl_port)
556		return;
557
558	owl_uart_port_write(&owl_port->port, s, count);
559}
560
561static int owl_uart_console_setup(struct console *co, char *options)
562{
563	struct owl_uart_port *owl_port;
564	int baud = 115200;
565	int bits = 8;
566	int parity = 'n';
567	int flow = 'n';
568
569	if (co->index < 0 || co->index >= OWL_UART_PORT_NUM)
570		return -EINVAL;
571
572	owl_port = owl_uart_ports[co->index];
573	if (!owl_port || !owl_port->port.membase)
574		return -ENODEV;
575
576	if (options)
577		uart_parse_options(options, &baud, &parity, &bits, &flow);
578
579	return uart_set_options(&owl_port->port, co, baud, parity, bits, flow);
580}
581
582static struct console owl_uart_console = {
583	.name = OWL_UART_DEV_NAME,
584	.write = owl_uart_console_write,
585	.device = uart_console_device,
586	.setup = owl_uart_console_setup,
587	.flags = CON_PRINTBUFFER,
588	.index = -1,
589	.data = &owl_uart_driver,
590};
591
592static int __init owl_uart_console_init(void)
593{
594	register_console(&owl_uart_console);
595
596	return 0;
597}
598console_initcall(owl_uart_console_init);
599
600static void owl_uart_early_console_write(struct console *co,
601					 const char *s,
602					 u_int count)
603{
604	struct earlycon_device *dev = co->data;
605
606	owl_uart_port_write(&dev->port, s, count);
607}
608
609static int __init
610owl_uart_early_console_setup(struct earlycon_device *device, const char *opt)
611{
612	if (!device->port.membase)
613		return -ENODEV;
614
615	device->con->write = owl_uart_early_console_write;
616
617	return 0;
618}
619OF_EARLYCON_DECLARE(owl, "actions,owl-uart",
620		    owl_uart_early_console_setup);
621
622#define OWL_UART_CONSOLE (&owl_uart_console)
623#else
624#define OWL_UART_CONSOLE NULL
625#endif
626
627static struct uart_driver owl_uart_driver = {
628	.owner = THIS_MODULE,
629	.driver_name = "owl-uart",
630	.dev_name = OWL_UART_DEV_NAME,
631	.nr = OWL_UART_PORT_NUM,
632	.cons = OWL_UART_CONSOLE,
633};
634
635static const struct owl_uart_info owl_s500_info = {
636	.tx_fifosize = 16,
637};
638
639static const struct owl_uart_info owl_s900_info = {
640	.tx_fifosize = 32,
641};
642
643static const struct of_device_id owl_uart_dt_matches[] = {
644	{ .compatible = "actions,s500-uart", .data = &owl_s500_info },
645	{ .compatible = "actions,s900-uart", .data = &owl_s900_info },
646	{ }
647};
648MODULE_DEVICE_TABLE(of, owl_uart_dt_matches);
649
650static int owl_uart_probe(struct platform_device *pdev)
651{
652	const struct of_device_id *match;
653	const struct owl_uart_info *info = NULL;
654	struct resource *res_mem;
655	struct owl_uart_port *owl_port;
656	int ret, irq;
657
658	if (pdev->dev.of_node) {
659		pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
660		match = of_match_node(owl_uart_dt_matches, pdev->dev.of_node);
661		if (match)
662			info = match->data;
663	}
664
665	if (pdev->id < 0 || pdev->id >= OWL_UART_PORT_NUM) {
666		dev_err(&pdev->dev, "id %d out of range\n", pdev->id);
667		return -EINVAL;
668	}
669
670	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
671	if (!res_mem) {
672		dev_err(&pdev->dev, "could not get mem\n");
673		return -ENODEV;
674	}
675
676	irq = platform_get_irq(pdev, 0);
677	if (irq < 0)
678		return irq;
679
680	if (owl_uart_ports[pdev->id]) {
681		dev_err(&pdev->dev, "port %d already allocated\n", pdev->id);
682		return -EBUSY;
683	}
684
685	owl_port = devm_kzalloc(&pdev->dev, sizeof(*owl_port), GFP_KERNEL);
686	if (!owl_port)
687		return -ENOMEM;
688
689	owl_port->clk = devm_clk_get(&pdev->dev, NULL);
690	if (IS_ERR(owl_port->clk)) {
691		dev_err(&pdev->dev, "could not get clk\n");
692		return PTR_ERR(owl_port->clk);
693	}
694
695	ret = clk_prepare_enable(owl_port->clk);
696	if (ret) {
697		dev_err(&pdev->dev, "could not enable clk\n");
698		return ret;
699	}
700
701	owl_port->port.dev = &pdev->dev;
702	owl_port->port.line = pdev->id;
703	owl_port->port.type = PORT_OWL;
704	owl_port->port.iotype = UPIO_MEM;
705	owl_port->port.mapbase = res_mem->start;
706	owl_port->port.irq = irq;
707	owl_port->port.uartclk = clk_get_rate(owl_port->clk);
708	if (owl_port->port.uartclk == 0) {
709		dev_err(&pdev->dev, "clock rate is zero\n");
710		clk_disable_unprepare(owl_port->clk);
711		return -EINVAL;
712	}
713	owl_port->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP | UPF_LOW_LATENCY;
714	owl_port->port.x_char = 0;
715	owl_port->port.fifosize = (info) ? info->tx_fifosize : 16;
716	owl_port->port.ops = &owl_uart_ops;
717
718	owl_uart_ports[pdev->id] = owl_port;
719	platform_set_drvdata(pdev, owl_port);
720
721	ret = uart_add_one_port(&owl_uart_driver, &owl_port->port);
722	if (ret)
723		owl_uart_ports[pdev->id] = NULL;
724
725	return ret;
726}
727
728static void owl_uart_remove(struct platform_device *pdev)
729{
730	struct owl_uart_port *owl_port = platform_get_drvdata(pdev);
731
732	uart_remove_one_port(&owl_uart_driver, &owl_port->port);
733	owl_uart_ports[pdev->id] = NULL;
734	clk_disable_unprepare(owl_port->clk);
735}
736
737static struct platform_driver owl_uart_platform_driver = {
738	.probe = owl_uart_probe,
739	.remove_new = owl_uart_remove,
740	.driver = {
741		.name = "owl-uart",
742		.of_match_table = owl_uart_dt_matches,
743	},
744};
745
746static int __init owl_uart_init(void)
747{
748	int ret;
749
750	ret = uart_register_driver(&owl_uart_driver);
751	if (ret)
752		return ret;
753
754	ret = platform_driver_register(&owl_uart_platform_driver);
755	if (ret)
756		uart_unregister_driver(&owl_uart_driver);
757
758	return ret;
759}
760
761static void __exit owl_uart_exit(void)
762{
763	platform_driver_unregister(&owl_uart_platform_driver);
764	uart_unregister_driver(&owl_uart_driver);
765}
766
767module_init(owl_uart_init);
768module_exit(owl_uart_exit);
769
770MODULE_LICENSE("GPL");