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, addr: port->membase + off);
87}
88
89static inline u32 owl_uart_read(struct uart_port *port, unsigned int off)
90{
91 return readl(addr: 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, val: 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(up: port, flags: &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(up: 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: &port->state->port, ch: val, flag);
222
223 stat = owl_uart_read(port, OWL_UART_STAT);
224 }
225
226 tty_flip_buffer_push(port: &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(up: port, flags: &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, val: stat, OWL_UART_STAT);
248
249 uart_port_unlock_irqrestore(up: 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(up: port, flags: &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(up: 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(irq: port->irq, handler: owl_uart_irq, IRQF_TRIGGER_HIGH,
278 name: "owl-uart", dev: port);
279 if (ret)
280 return ret;
281
282 uart_port_lock_irqsave(up: port, flags: &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(up: 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(clk: owl_port->clk, rate: 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(up: port, flags: &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, val: ctl, OWL_UART_CTL);
360
361 baud = uart_get_baud_rate(port, termios, old, min: 9600, max: 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, ibaud: baud, obaud: 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, cflag: termios->c_cflag, baud);
373
374 uart_port_unlock_irqrestore(up: 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(dev: port->dev, addr: 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(dev: port->dev, offset: port->mapbase,
409 size: 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, val: 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, val: 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(up: port);
519 else {
520 uart_port_lock(up: 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, putchar: 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, val: old_ctl, OWL_UART_CTL);
542
543 if (locked)
544 uart_port_unlock(up: 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(port: &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: &baud, parity: &parity, bits: &bits, flow: &flow);
578
579 return uart_set_options(port: &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(port: &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(np: pdev->dev.of_node, stem: "serial");
660 match = of_match_node(matches: owl_uart_dt_matches, node: 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(dev: &pdev->dev, size: sizeof(*owl_port), GFP_KERNEL);
686 if (!owl_port)
687 return -ENOMEM;
688
689 owl_port->clk = devm_clk_get(dev: &pdev->dev, NULL);
690 if (IS_ERR(ptr: owl_port->clk)) {
691 dev_err(&pdev->dev, "could not get clk\n");
692 return PTR_ERR(ptr: owl_port->clk);
693 }
694
695 ret = clk_prepare_enable(clk: 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(clk: owl_port->clk);
708 if (owl_port->port.uartclk == 0) {
709 dev_err(&pdev->dev, "clock rate is zero\n");
710 clk_disable_unprepare(clk: 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, data: owl_port);
720
721 ret = uart_add_one_port(reg: &owl_uart_driver, port: &owl_port->port);
722 if (ret)
723 owl_uart_ports[pdev->id] = NULL;
724
725 return ret;
726}
727
728static int 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(reg: &owl_uart_driver, port: &owl_port->port);
733 owl_uart_ports[pdev->id] = NULL;
734 clk_disable_unprepare(clk: owl_port->clk);
735
736 return 0;
737}
738
739static struct platform_driver owl_uart_platform_driver = {
740 .probe = owl_uart_probe,
741 .remove = owl_uart_remove,
742 .driver = {
743 .name = "owl-uart",
744 .of_match_table = owl_uart_dt_matches,
745 },
746};
747
748static int __init owl_uart_init(void)
749{
750 int ret;
751
752 ret = uart_register_driver(uart: &owl_uart_driver);
753 if (ret)
754 return ret;
755
756 ret = platform_driver_register(&owl_uart_platform_driver);
757 if (ret)
758 uart_unregister_driver(uart: &owl_uart_driver);
759
760 return ret;
761}
762
763static void __exit owl_uart_exit(void)
764{
765 platform_driver_unregister(&owl_uart_platform_driver);
766 uart_unregister_driver(uart: &owl_uart_driver);
767}
768
769module_init(owl_uart_init);
770module_exit(owl_uart_exit);
771
772MODULE_LICENSE("GPL");
773

source code of linux/drivers/tty/serial/owl-uart.c