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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * uartlite.c: Serial driver for Xilinx uartlite serial controller
4 *
5 * Copyright (C) 2006 Peter Korsgaard <jacmet@sunsite.dk>
6 * Copyright (C) 2007 Secret Lab Technologies Ltd.
7 */
8
9#include <linux/platform_device.h>
10#include <linux/module.h>
11#include <linux/console.h>
12#include <linux/serial.h>
13#include <linux/serial_core.h>
14#include <linux/tty.h>
15#include <linux/tty_flip.h>
16#include <linux/delay.h>
17#include <linux/interrupt.h>
18#include <linux/init.h>
19#include <linux/io.h>
20#include <linux/of.h>
21#include <linux/of_address.h>
22#include <linux/of_device.h>
23#include <linux/of_platform.h>
24#include <linux/clk.h>
25
26#define ULITE_NAME "ttyUL"
27#define ULITE_MAJOR 204
28#define ULITE_MINOR 187
29#define ULITE_NR_UARTS CONFIG_SERIAL_UARTLITE_NR_UARTS
30
31/* ---------------------------------------------------------------------
32 * Register definitions
33 *
34 * For register details see datasheet:
35 * http://www.xilinx.com/support/documentation/ip_documentation/opb_uartlite.pdf
36 */
37
38#define ULITE_RX 0x00
39#define ULITE_TX 0x04
40#define ULITE_STATUS 0x08
41#define ULITE_CONTROL 0x0c
42
43#define ULITE_REGION 16
44
45#define ULITE_STATUS_RXVALID 0x01
46#define ULITE_STATUS_RXFULL 0x02
47#define ULITE_STATUS_TXEMPTY 0x04
48#define ULITE_STATUS_TXFULL 0x08
49#define ULITE_STATUS_IE 0x10
50#define ULITE_STATUS_OVERRUN 0x20
51#define ULITE_STATUS_FRAME 0x40
52#define ULITE_STATUS_PARITY 0x80
53
54#define ULITE_CONTROL_RST_TX 0x01
55#define ULITE_CONTROL_RST_RX 0x02
56#define ULITE_CONTROL_IE 0x10
57
58struct uartlite_data {
59 const struct uartlite_reg_ops *reg_ops;
60 struct clk *clk;
61};
62
63struct uartlite_reg_ops {
64 u32 (*in)(void __iomem *addr);
65 void (*out)(u32 val, void __iomem *addr);
66};
67
68static u32 uartlite_inbe32(void __iomem *addr)
69{
70 return ioread32be(addr);
71}
72
73static void uartlite_outbe32(u32 val, void __iomem *addr)
74{
75 iowrite32be(val, addr);
76}
77
78static const struct uartlite_reg_ops uartlite_be = {
79 .in = uartlite_inbe32,
80 .out = uartlite_outbe32,
81};
82
83static u32 uartlite_inle32(void __iomem *addr)
84{
85 return ioread32(addr);
86}
87
88static void uartlite_outle32(u32 val, void __iomem *addr)
89{
90 iowrite32(val, addr);
91}
92
93static const struct uartlite_reg_ops uartlite_le = {
94 .in = uartlite_inle32,
95 .out = uartlite_outle32,
96};
97
98static inline u32 uart_in32(u32 offset, struct uart_port *port)
99{
100 struct uartlite_data *pdata = port->private_data;
101
102 return pdata->reg_ops->in(port->membase + offset);
103}
104
105static inline void uart_out32(u32 val, u32 offset, struct uart_port *port)
106{
107 struct uartlite_data *pdata = port->private_data;
108
109 pdata->reg_ops->out(val, port->membase + offset);
110}
111
112static struct uart_port ulite_ports[ULITE_NR_UARTS];
113
114/* ---------------------------------------------------------------------
115 * Core UART driver operations
116 */
117
118static int ulite_receive(struct uart_port *port, int stat)
119{
120 struct tty_port *tport = &port->state->port;
121 unsigned char ch = 0;
122 char flag = TTY_NORMAL;
123
124 if ((stat & (ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
125 | ULITE_STATUS_FRAME)) == 0)
126 return 0;
127
128 /* stats */
129 if (stat & ULITE_STATUS_RXVALID) {
130 port->icount.rx++;
131 ch = uart_in32(ULITE_RX, port);
132
133 if (stat & ULITE_STATUS_PARITY)
134 port->icount.parity++;
135 }
136
137 if (stat & ULITE_STATUS_OVERRUN)
138 port->icount.overrun++;
139
140 if (stat & ULITE_STATUS_FRAME)
141 port->icount.frame++;
142
143
144 /* drop byte with parity error if IGNPAR specificed */
145 if (stat & port->ignore_status_mask & ULITE_STATUS_PARITY)
146 stat &= ~ULITE_STATUS_RXVALID;
147
148 stat &= port->read_status_mask;
149
150 if (stat & ULITE_STATUS_PARITY)
151 flag = TTY_PARITY;
152
153
154 stat &= ~port->ignore_status_mask;
155
156 if (stat & ULITE_STATUS_RXVALID)
157 tty_insert_flip_char(tport, ch, flag);
158
159 if (stat & ULITE_STATUS_FRAME)
160 tty_insert_flip_char(tport, 0, TTY_FRAME);
161
162 if (stat & ULITE_STATUS_OVERRUN)
163 tty_insert_flip_char(tport, 0, TTY_OVERRUN);
164
165 return 1;
166}
167
168static int ulite_transmit(struct uart_port *port, int stat)
169{
170 struct circ_buf *xmit = &port->state->xmit;
171
172 if (stat & ULITE_STATUS_TXFULL)
173 return 0;
174
175 if (port->x_char) {
176 uart_out32(port->x_char, ULITE_TX, port);
177 port->x_char = 0;
178 port->icount.tx++;
179 return 1;
180 }
181
182 if (uart_circ_empty(xmit) || uart_tx_stopped(port))
183 return 0;
184
185 uart_out32(xmit->buf[xmit->tail], ULITE_TX, port);
186 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
187 port->icount.tx++;
188
189 /* wake up */
190 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
191 uart_write_wakeup(port);
192
193 return 1;
194}
195
196static irqreturn_t ulite_isr(int irq, void *dev_id)
197{
198 struct uart_port *port = dev_id;
199 int stat, busy, n = 0;
200 unsigned long flags;
201
202 do {
203 spin_lock_irqsave(&port->lock, flags);
204 stat = uart_in32(ULITE_STATUS, port);
205 busy = ulite_receive(port, stat);
206 busy |= ulite_transmit(port, stat);
207 spin_unlock_irqrestore(&port->lock, flags);
208 n++;
209 } while (busy);
210
211 /* work done? */
212 if (n > 1) {
213 tty_flip_buffer_push(&port->state->port);
214 return IRQ_HANDLED;
215 } else {
216 return IRQ_NONE;
217 }
218}
219
220static unsigned int ulite_tx_empty(struct uart_port *port)
221{
222 unsigned long flags;
223 unsigned int ret;
224
225 spin_lock_irqsave(&port->lock, flags);
226 ret = uart_in32(ULITE_STATUS, port);
227 spin_unlock_irqrestore(&port->lock, flags);
228
229 return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0;
230}
231
232static unsigned int ulite_get_mctrl(struct uart_port *port)
233{
234 return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
235}
236
237static void ulite_set_mctrl(struct uart_port *port, unsigned int mctrl)
238{
239 /* N/A */
240}
241
242static void ulite_stop_tx(struct uart_port *port)
243{
244 /* N/A */
245}
246
247static void ulite_start_tx(struct uart_port *port)
248{
249 ulite_transmit(port, uart_in32(ULITE_STATUS, port));
250}
251
252static void ulite_stop_rx(struct uart_port *port)
253{
254 /* don't forward any more data (like !CREAD) */
255 port->ignore_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
256 | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
257}
258
259static void ulite_break_ctl(struct uart_port *port, int ctl)
260{
261 /* N/A */
262}
263
264static int ulite_startup(struct uart_port *port)
265{
266 struct uartlite_data *pdata = port->private_data;
267 int ret;
268
269 ret = clk_enable(pdata->clk);
270 if (ret) {
271 dev_err(port->dev, "Failed to enable clock\n");
272 return ret;
273 }
274
275 ret = request_irq(port->irq, ulite_isr, IRQF_SHARED | IRQF_TRIGGER_RISING,
276 "uartlite", port);
277 if (ret)
278 return ret;
279
280 uart_out32(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX,
281 ULITE_CONTROL, port);
282 uart_out32(ULITE_CONTROL_IE, ULITE_CONTROL, port);
283
284 return 0;
285}
286
287static void ulite_shutdown(struct uart_port *port)
288{
289 struct uartlite_data *pdata = port->private_data;
290
291 uart_out32(0, ULITE_CONTROL, port);
292 uart_in32(ULITE_CONTROL, port); /* dummy */
293 free_irq(port->irq, port);
294 clk_disable(pdata->clk);
295}
296
297static void ulite_set_termios(struct uart_port *port, struct ktermios *termios,
298 struct ktermios *old)
299{
300 unsigned long flags;
301 unsigned int baud;
302
303 spin_lock_irqsave(&port->lock, flags);
304
305 port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
306 | ULITE_STATUS_TXFULL;
307
308 if (termios->c_iflag & INPCK)
309 port->read_status_mask |=
310 ULITE_STATUS_PARITY | ULITE_STATUS_FRAME;
311
312 port->ignore_status_mask = 0;
313 if (termios->c_iflag & IGNPAR)
314 port->ignore_status_mask |= ULITE_STATUS_PARITY
315 | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
316
317 /* ignore all characters if CREAD is not set */
318 if ((termios->c_cflag & CREAD) == 0)
319 port->ignore_status_mask |=
320 ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
321 | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
322
323 /* update timeout */
324 baud = uart_get_baud_rate(port, termios, old, 0, 460800);
325 uart_update_timeout(port, termios->c_cflag, baud);
326
327 spin_unlock_irqrestore(&port->lock, flags);
328}
329
330static const char *ulite_type(struct uart_port *port)
331{
332 return port->type == PORT_UARTLITE ? "uartlite" : NULL;
333}
334
335static void ulite_release_port(struct uart_port *port)
336{
337 release_mem_region(port->mapbase, ULITE_REGION);
338 iounmap(port->membase);
339 port->membase = NULL;
340}
341
342static int ulite_request_port(struct uart_port *port)
343{
344 struct uartlite_data *pdata = port->private_data;
345 int ret;
346
347 pr_debug("ulite console: port=%p; port->mapbase=%llx\n",
348 port, (unsigned long long) port->mapbase);
349
350 if (!request_mem_region(port->mapbase, ULITE_REGION, "uartlite")) {
351 dev_err(port->dev, "Memory region busy\n");
352 return -EBUSY;
353 }
354
355 port->membase = ioremap(port->mapbase, ULITE_REGION);
356 if (!port->membase) {
357 dev_err(port->dev, "Unable to map registers\n");
358 release_mem_region(port->mapbase, ULITE_REGION);
359 return -EBUSY;
360 }
361
362 pdata->reg_ops = &uartlite_be;
363 ret = uart_in32(ULITE_CONTROL, port);
364 uart_out32(ULITE_CONTROL_RST_TX, ULITE_CONTROL, port);
365 ret = uart_in32(ULITE_STATUS, port);
366 /* Endianess detection */
367 if ((ret & ULITE_STATUS_TXEMPTY) != ULITE_STATUS_TXEMPTY)
368 pdata->reg_ops = &uartlite_le;
369
370 return 0;
371}
372
373static void ulite_config_port(struct uart_port *port, int flags)
374{
375 if (!ulite_request_port(port))
376 port->type = PORT_UARTLITE;
377}
378
379static int ulite_verify_port(struct uart_port *port, struct serial_struct *ser)
380{
381 /* we don't want the core code to modify any port params */
382 return -EINVAL;
383}
384
385static void ulite_pm(struct uart_port *port, unsigned int state,
386 unsigned int oldstate)
387{
388 struct uartlite_data *pdata = port->private_data;
389
390 if (!state)
391 clk_enable(pdata->clk);
392 else
393 clk_disable(pdata->clk);
394}
395
396#ifdef CONFIG_CONSOLE_POLL
397static int ulite_get_poll_char(struct uart_port *port)
398{
399 if (!(uart_in32(ULITE_STATUS, port) & ULITE_STATUS_RXVALID))
400 return NO_POLL_CHAR;
401
402 return uart_in32(ULITE_RX, port);
403}
404
405static void ulite_put_poll_char(struct uart_port *port, unsigned char ch)
406{
407 while (uart_in32(ULITE_STATUS, port) & ULITE_STATUS_TXFULL)
408 cpu_relax();
409
410 /* write char to device */
411 uart_out32(ch, ULITE_TX, port);
412}
413#endif
414
415static const struct uart_ops ulite_ops = {
416 .tx_empty = ulite_tx_empty,
417 .set_mctrl = ulite_set_mctrl,
418 .get_mctrl = ulite_get_mctrl,
419 .stop_tx = ulite_stop_tx,
420 .start_tx = ulite_start_tx,
421 .stop_rx = ulite_stop_rx,
422 .break_ctl = ulite_break_ctl,
423 .startup = ulite_startup,
424 .shutdown = ulite_shutdown,
425 .set_termios = ulite_set_termios,
426 .type = ulite_type,
427 .release_port = ulite_release_port,
428 .request_port = ulite_request_port,
429 .config_port = ulite_config_port,
430 .verify_port = ulite_verify_port,
431 .pm = ulite_pm,
432#ifdef CONFIG_CONSOLE_POLL
433 .poll_get_char = ulite_get_poll_char,
434 .poll_put_char = ulite_put_poll_char,
435#endif
436};
437
438/* ---------------------------------------------------------------------
439 * Console driver operations
440 */
441
442#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
443static void ulite_console_wait_tx(struct uart_port *port)
444{
445 u8 val;
446 unsigned long timeout;
447
448 /*
449 * Spin waiting for TX fifo to have space available.
450 * When using the Microblaze Debug Module this can take up to 1s
451 */
452 timeout = jiffies + msecs_to_jiffies(1000);
453 while (1) {
454 val = uart_in32(ULITE_STATUS, port);
455 if ((val & ULITE_STATUS_TXFULL) == 0)
456 break;
457 if (time_after(jiffies, timeout)) {
458 dev_warn(port->dev,
459 "timeout waiting for TX buffer empty\n");
460 break;
461 }
462 cpu_relax();
463 }
464}
465
466static void ulite_console_putchar(struct uart_port *port, int ch)
467{
468 ulite_console_wait_tx(port);
469 uart_out32(ch, ULITE_TX, port);
470}
471
472static void ulite_console_write(struct console *co, const char *s,
473 unsigned int count)
474{
475 struct uart_port *port = &ulite_ports[co->index];
476 unsigned long flags;
477 unsigned int ier;
478 int locked = 1;
479
480 if (oops_in_progress) {
481 locked = spin_trylock_irqsave(&port->lock, flags);
482 } else
483 spin_lock_irqsave(&port->lock, flags);
484
485 /* save and disable interrupt */
486 ier = uart_in32(ULITE_STATUS, port) & ULITE_STATUS_IE;
487 uart_out32(0, ULITE_CONTROL, port);
488
489 uart_console_write(port, s, count, ulite_console_putchar);
490
491 ulite_console_wait_tx(port);
492
493 /* restore interrupt state */
494 if (ier)
495 uart_out32(ULITE_CONTROL_IE, ULITE_CONTROL, port);
496
497 if (locked)
498 spin_unlock_irqrestore(&port->lock, flags);
499}
500
501static int ulite_console_setup(struct console *co, char *options)
502{
503 struct uart_port *port;
504 int baud = 9600;
505 int bits = 8;
506 int parity = 'n';
507 int flow = 'n';
508
509 if (co->index < 0 || co->index >= ULITE_NR_UARTS)
510 return -EINVAL;
511
512 port = &ulite_ports[co->index];
513
514 /* Has the device been initialized yet? */
515 if (!port->mapbase) {
516 pr_debug("console on ttyUL%i not present\n", co->index);
517 return -ENODEV;
518 }
519
520 /* not initialized yet? */
521 if (!port->membase) {
522 if (ulite_request_port(port))
523 return -ENODEV;
524 }
525
526 if (options)
527 uart_parse_options(options, &baud, &parity, &bits, &flow);
528
529 return uart_set_options(port, co, baud, parity, bits, flow);
530}
531
532static struct uart_driver ulite_uart_driver;
533
534static struct console ulite_console = {
535 .name = ULITE_NAME,
536 .write = ulite_console_write,
537 .device = uart_console_device,
538 .setup = ulite_console_setup,
539 .flags = CON_PRINTBUFFER,
540 .index = -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */
541 .data = &ulite_uart_driver,
542};
543
544static int __init ulite_console_init(void)
545{
546 register_console(&ulite_console);
547 return 0;
548}
549
550console_initcall(ulite_console_init);
551
552static void early_uartlite_putc(struct uart_port *port, int c)
553{
554 /*
555 * Limit how many times we'll spin waiting for TX FIFO status.
556 * This will prevent lockups if the base address is incorrectly
557 * set, or any other issue on the UARTLITE.
558 * This limit is pretty arbitrary, unless we are at about 10 baud
559 * we'll never timeout on a working UART.
560 */
561
562 unsigned retries = 1000000;
563 /* read status bit - 0x8 offset */
564 while (--retries && (readl(port->membase + 8) & (1 << 3)))
565 ;
566
567 /* Only attempt the iowrite if we didn't timeout */
568 /* write to TX_FIFO - 0x4 offset */
569 if (retries)
570 writel(c & 0xff, port->membase + 4);
571}
572
573static void early_uartlite_write(struct console *console,
574 const char *s, unsigned n)
575{
576 struct earlycon_device *device = console->data;
577 uart_console_write(&device->port, s, n, early_uartlite_putc);
578}
579
580static int __init early_uartlite_setup(struct earlycon_device *device,
581 const char *options)
582{
583 if (!device->port.membase)
584 return -ENODEV;
585
586 device->con->write = early_uartlite_write;
587 return 0;
588}
589EARLYCON_DECLARE(uartlite, early_uartlite_setup);
590OF_EARLYCON_DECLARE(uartlite_b, "xlnx,opb-uartlite-1.00.b", early_uartlite_setup);
591OF_EARLYCON_DECLARE(uartlite_a, "xlnx,xps-uartlite-1.00.a", early_uartlite_setup);
592
593#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
594
595static struct uart_driver ulite_uart_driver = {
596 .owner = THIS_MODULE,
597 .driver_name = "uartlite",
598 .dev_name = ULITE_NAME,
599 .major = ULITE_MAJOR,
600 .minor = ULITE_MINOR,
601 .nr = ULITE_NR_UARTS,
602#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
603 .cons = &ulite_console,
604#endif
605};
606
607/* ---------------------------------------------------------------------
608 * Port assignment functions (mapping devices to uart_port structures)
609 */
610
611/** ulite_assign: register a uartlite device with the driver
612 *
613 * @dev: pointer to device structure
614 * @id: requested id number. Pass -1 for automatic port assignment
615 * @base: base address of uartlite registers
616 * @irq: irq number for uartlite
617 * @pdata: private data for uartlite
618 *
619 * Returns: 0 on success, <0 otherwise
620 */
621static int ulite_assign(struct device *dev, int id, u32 base, int irq,
622 struct uartlite_data *pdata)
623{
624 struct uart_port *port;
625 int rc;
626
627 /* if id = -1; then scan for a free id and use that */
628 if (id < 0) {
629 for (id = 0; id < ULITE_NR_UARTS; id++)
630 if (ulite_ports[id].mapbase == 0)
631 break;
632 }
633 if (id < 0 || id >= ULITE_NR_UARTS) {
634 dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
635 return -EINVAL;
636 }
637
638 if ((ulite_ports[id].mapbase) && (ulite_ports[id].mapbase != base)) {
639 dev_err(dev, "cannot assign to %s%i; it is already in use\n",
640 ULITE_NAME, id);
641 return -EBUSY;
642 }
643
644 port = &ulite_ports[id];
645
646 spin_lock_init(&port->lock);
647 port->fifosize = 16;
648 port->regshift = 2;
649 port->iotype = UPIO_MEM;
650 port->iobase = 1; /* mark port in use */
651 port->mapbase = base;
652 port->membase = NULL;
653 port->ops = &ulite_ops;
654 port->irq = irq;
655 port->flags = UPF_BOOT_AUTOCONF;
656 port->dev = dev;
657 port->type = PORT_UNKNOWN;
658 port->line = id;
659 port->private_data = pdata;
660
661 dev_set_drvdata(dev, port);
662
663 /* Register the port */
664 rc = uart_add_one_port(&ulite_uart_driver, port);
665 if (rc) {
666 dev_err(dev, "uart_add_one_port() failed; err=%i\n", rc);
667 port->mapbase = 0;
668 dev_set_drvdata(dev, NULL);
669 return rc;
670 }
671
672 return 0;
673}
674
675/** ulite_release: register a uartlite device with the driver
676 *
677 * @dev: pointer to device structure
678 */
679static int ulite_release(struct device *dev)
680{
681 struct uart_port *port = dev_get_drvdata(dev);
682 int rc = 0;
683
684 if (port) {
685 rc = uart_remove_one_port(&ulite_uart_driver, port);
686 dev_set_drvdata(dev, NULL);
687 port->mapbase = 0;
688 }
689
690 return rc;
691}
692
693/**
694 * ulite_suspend - Stop the device.
695 *
696 * @dev: handle to the device structure.
697 * Return: 0 always.
698 */
699static int __maybe_unused ulite_suspend(struct device *dev)
700{
701 struct uart_port *port = dev_get_drvdata(dev);
702
703 if (port)
704 uart_suspend_port(&ulite_uart_driver, port);
705
706 return 0;
707}
708
709/**
710 * ulite_resume - Resume the device.
711 *
712 * @dev: handle to the device structure.
713 * Return: 0 on success, errno otherwise.
714 */
715static int __maybe_unused ulite_resume(struct device *dev)
716{
717 struct uart_port *port = dev_get_drvdata(dev);
718
719 if (port)
720 uart_resume_port(&ulite_uart_driver, port);
721
722 return 0;
723}
724
725/* ---------------------------------------------------------------------
726 * Platform bus binding
727 */
728
729static SIMPLE_DEV_PM_OPS(ulite_pm_ops, ulite_suspend, ulite_resume);
730
731#if defined(CONFIG_OF)
732/* Match table for of_platform binding */
733static const struct of_device_id ulite_of_match[] = {
734 { .compatible = "xlnx,opb-uartlite-1.00.b", },
735 { .compatible = "xlnx,xps-uartlite-1.00.a", },
736 {}
737};
738MODULE_DEVICE_TABLE(of, ulite_of_match);
739#endif /* CONFIG_OF */
740
741static int ulite_probe(struct platform_device *pdev)
742{
743 struct resource *res;
744 struct uartlite_data *pdata;
745 int irq, ret;
746 int id = pdev->id;
747#ifdef CONFIG_OF
748 const __be32 *prop;
749
750 prop = of_get_property(pdev->dev.of_node, "port-number", NULL);
751 if (prop)
752 id = be32_to_cpup(prop);
753#endif
754 pdata = devm_kzalloc(&pdev->dev, sizeof(struct uartlite_data),
755 GFP_KERNEL);
756 if (!pdata)
757 return -ENOMEM;
758
759 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
760 if (!res)
761 return -ENODEV;
762
763 irq = platform_get_irq(pdev, 0);
764 if (irq <= 0)
765 return -ENXIO;
766
767 pdata->clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
768 if (IS_ERR(pdata->clk)) {
769 if (PTR_ERR(pdata->clk) != -ENOENT)
770 return PTR_ERR(pdata->clk);
771
772 /*
773 * Clock framework support is optional, continue on
774 * anyways if we don't find a matching clock.
775 */
776 pdata->clk = NULL;
777 }
778
779 ret = clk_prepare(pdata->clk);
780 if (ret) {
781 dev_err(&pdev->dev, "Failed to prepare clock\n");
782 return ret;
783 }
784
785 return ulite_assign(&pdev->dev, id, res->start, irq, pdata);
786}
787
788static int ulite_remove(struct platform_device *pdev)
789{
790 struct uart_port *port = dev_get_drvdata(&pdev->dev);
791 struct uartlite_data *pdata = port->private_data;
792
793 clk_disable_unprepare(pdata->clk);
794 return ulite_release(&pdev->dev);
795}
796
797/* work with hotplug and coldplug */
798MODULE_ALIAS("platform:uartlite");
799
800static struct platform_driver ulite_platform_driver = {
801 .probe = ulite_probe,
802 .remove = ulite_remove,
803 .driver = {
804 .name = "uartlite",
805 .of_match_table = of_match_ptr(ulite_of_match),
806 .pm = &ulite_pm_ops,
807 },
808};
809
810/* ---------------------------------------------------------------------
811 * Module setup/teardown
812 */
813
814static int __init ulite_init(void)
815{
816 int ret;
817
818 pr_debug("uartlite: calling uart_register_driver()\n");
819 ret = uart_register_driver(&ulite_uart_driver);
820 if (ret)
821 goto err_uart;
822
823 pr_debug("uartlite: calling platform_driver_register()\n");
824 ret = platform_driver_register(&ulite_platform_driver);
825 if (ret)
826 goto err_plat;
827
828 return 0;
829
830err_plat:
831 uart_unregister_driver(&ulite_uart_driver);
832err_uart:
833 pr_err("registering uartlite driver failed: err=%i\n", ret);
834 return ret;
835}
836
837static void __exit ulite_exit(void)
838{
839 platform_driver_unregister(&ulite_platform_driver);
840 uart_unregister_driver(&ulite_uart_driver);
841}
842
843module_init(ulite_init);
844module_exit(ulite_exit);
845
846MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
847MODULE_DESCRIPTION("Xilinx uartlite serial driver");
848MODULE_LICENSE("GPL");