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Merge tag 'for-linus-4.4-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git...
[deliverable/linux.git] / drivers / tty / serial / vt8500_serial.c
1 /*
2 * Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
3 *
4 * Based on msm_serial.c, which is:
5 * Copyright (C) 2007 Google, Inc.
6 * Author: Robert Love <rlove@google.com>
7 *
8 * This software is licensed under the terms of the GNU General Public
9 * License version 2, as published by the Free Software Foundation, and
10 * may be copied, distributed, and modified under those terms.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 */
17
18 #if defined(CONFIG_SERIAL_VT8500_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
19 # define SUPPORT_SYSRQ
20 #endif
21
22 #include <linux/hrtimer.h>
23 #include <linux/delay.h>
24 #include <linux/module.h>
25 #include <linux/io.h>
26 #include <linux/ioport.h>
27 #include <linux/irq.h>
28 #include <linux/init.h>
29 #include <linux/console.h>
30 #include <linux/tty.h>
31 #include <linux/tty_flip.h>
32 #include <linux/serial_core.h>
33 #include <linux/serial.h>
34 #include <linux/slab.h>
35 #include <linux/clk.h>
36 #include <linux/of.h>
37 #include <linux/of_device.h>
38 #include <linux/err.h>
39
40 /*
41 * UART Register offsets
42 */
43
44 #define VT8500_URTDR 0x0000 /* Transmit data */
45 #define VT8500_URRDR 0x0004 /* Receive data */
46 #define VT8500_URDIV 0x0008 /* Clock/Baud rate divisor */
47 #define VT8500_URLCR 0x000C /* Line control */
48 #define VT8500_URICR 0x0010 /* IrDA control */
49 #define VT8500_URIER 0x0014 /* Interrupt enable */
50 #define VT8500_URISR 0x0018 /* Interrupt status */
51 #define VT8500_URUSR 0x001c /* UART status */
52 #define VT8500_URFCR 0x0020 /* FIFO control */
53 #define VT8500_URFIDX 0x0024 /* FIFO index */
54 #define VT8500_URBKR 0x0028 /* Break signal count */
55 #define VT8500_URTOD 0x002c /* Time out divisor */
56 #define VT8500_TXFIFO 0x1000 /* Transmit FIFO (16x8) */
57 #define VT8500_RXFIFO 0x1020 /* Receive FIFO (16x10) */
58
59 /*
60 * Interrupt enable and status bits
61 */
62
63 #define TXDE (1 << 0) /* Tx Data empty */
64 #define RXDF (1 << 1) /* Rx Data full */
65 #define TXFAE (1 << 2) /* Tx FIFO almost empty */
66 #define TXFE (1 << 3) /* Tx FIFO empty */
67 #define RXFAF (1 << 4) /* Rx FIFO almost full */
68 #define RXFF (1 << 5) /* Rx FIFO full */
69 #define TXUDR (1 << 6) /* Tx underrun */
70 #define RXOVER (1 << 7) /* Rx overrun */
71 #define PER (1 << 8) /* Parity error */
72 #define FER (1 << 9) /* Frame error */
73 #define TCTS (1 << 10) /* Toggle of CTS */
74 #define RXTOUT (1 << 11) /* Rx timeout */
75 #define BKDONE (1 << 12) /* Break signal done */
76 #define ERR (1 << 13) /* AHB error response */
77
78 #define RX_FIFO_INTS (RXFAF | RXFF | RXOVER | PER | FER | RXTOUT)
79 #define TX_FIFO_INTS (TXFAE | TXFE | TXUDR)
80
81 /*
82 * Line control bits
83 */
84
85 #define VT8500_TXEN (1 << 0) /* Enable transmit logic */
86 #define VT8500_RXEN (1 << 1) /* Enable receive logic */
87 #define VT8500_CS8 (1 << 2) /* 8-bit data length (vs. 7-bit) */
88 #define VT8500_CSTOPB (1 << 3) /* 2 stop bits (vs. 1) */
89 #define VT8500_PARENB (1 << 4) /* Enable parity */
90 #define VT8500_PARODD (1 << 5) /* Odd parity (vs. even) */
91 #define VT8500_RTS (1 << 6) /* Ready to send */
92 #define VT8500_LOOPBK (1 << 7) /* Enable internal loopback */
93 #define VT8500_DMA (1 << 8) /* Enable DMA mode (needs FIFO) */
94 #define VT8500_BREAK (1 << 9) /* Initiate break signal */
95 #define VT8500_PSLVERR (1 << 10) /* APB error upon empty RX FIFO read */
96 #define VT8500_SWRTSCTS (1 << 11) /* Software-controlled RTS/CTS */
97
98 /*
99 * Capability flags (driver-internal)
100 */
101
102 #define VT8500_HAS_SWRTSCTS_SWITCH (1 << 1)
103
104 #define VT8500_RECOMMENDED_CLK 12000000
105 #define VT8500_OVERSAMPLING_DIVISOR 13
106 #define VT8500_MAX_PORTS 6
107
108 struct vt8500_port {
109 struct uart_port uart;
110 char name[16];
111 struct clk *clk;
112 unsigned int clk_predivisor;
113 unsigned int ier;
114 unsigned int vt8500_uart_flags;
115 };
116
117 /*
118 * we use this variable to keep track of which ports
119 * have been allocated as we can't use pdev->id in
120 * devicetree
121 */
122 static unsigned long vt8500_ports_in_use;
123
124 static inline void vt8500_write(struct uart_port *port, unsigned int val,
125 unsigned int off)
126 {
127 writel(val, port->membase + off);
128 }
129
130 static inline unsigned int vt8500_read(struct uart_port *port, unsigned int off)
131 {
132 return readl(port->membase + off);
133 }
134
135 static void vt8500_stop_tx(struct uart_port *port)
136 {
137 struct vt8500_port *vt8500_port = container_of(port,
138 struct vt8500_port,
139 uart);
140
141 vt8500_port->ier &= ~TX_FIFO_INTS;
142 vt8500_write(port, vt8500_port->ier, VT8500_URIER);
143 }
144
145 static void vt8500_stop_rx(struct uart_port *port)
146 {
147 struct vt8500_port *vt8500_port = container_of(port,
148 struct vt8500_port,
149 uart);
150
151 vt8500_port->ier &= ~RX_FIFO_INTS;
152 vt8500_write(port, vt8500_port->ier, VT8500_URIER);
153 }
154
155 static void vt8500_enable_ms(struct uart_port *port)
156 {
157 struct vt8500_port *vt8500_port = container_of(port,
158 struct vt8500_port,
159 uart);
160
161 vt8500_port->ier |= TCTS;
162 vt8500_write(port, vt8500_port->ier, VT8500_URIER);
163 }
164
165 static void handle_rx(struct uart_port *port)
166 {
167 struct tty_port *tport = &port->state->port;
168
169 /*
170 * Handle overrun
171 */
172 if ((vt8500_read(port, VT8500_URISR) & RXOVER)) {
173 port->icount.overrun++;
174 tty_insert_flip_char(tport, 0, TTY_OVERRUN);
175 }
176
177 /* and now the main RX loop */
178 while (vt8500_read(port, VT8500_URFIDX) & 0x1f00) {
179 unsigned int c;
180 char flag = TTY_NORMAL;
181
182 c = readw(port->membase + VT8500_RXFIFO) & 0x3ff;
183
184 /* Mask conditions we're ignorning. */
185 c &= ~port->read_status_mask;
186
187 if (c & FER) {
188 port->icount.frame++;
189 flag = TTY_FRAME;
190 } else if (c & PER) {
191 port->icount.parity++;
192 flag = TTY_PARITY;
193 }
194 port->icount.rx++;
195
196 if (!uart_handle_sysrq_char(port, c))
197 tty_insert_flip_char(tport, c, flag);
198 }
199
200 spin_unlock(&port->lock);
201 tty_flip_buffer_push(tport);
202 spin_lock(&port->lock);
203 }
204
205 static void handle_tx(struct uart_port *port)
206 {
207 struct circ_buf *xmit = &port->state->xmit;
208
209 if (port->x_char) {
210 writeb(port->x_char, port->membase + VT8500_TXFIFO);
211 port->icount.tx++;
212 port->x_char = 0;
213 }
214 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
215 vt8500_stop_tx(port);
216 return;
217 }
218
219 while ((vt8500_read(port, VT8500_URFIDX) & 0x1f) < 16) {
220 if (uart_circ_empty(xmit))
221 break;
222
223 writeb(xmit->buf[xmit->tail], port->membase + VT8500_TXFIFO);
224
225 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
226 port->icount.tx++;
227 }
228
229 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
230 uart_write_wakeup(port);
231
232 if (uart_circ_empty(xmit))
233 vt8500_stop_tx(port);
234 }
235
236 static void vt8500_start_tx(struct uart_port *port)
237 {
238 struct vt8500_port *vt8500_port = container_of(port,
239 struct vt8500_port,
240 uart);
241
242 vt8500_port->ier &= ~TX_FIFO_INTS;
243 vt8500_write(port, vt8500_port->ier, VT8500_URIER);
244 handle_tx(port);
245 vt8500_port->ier |= TX_FIFO_INTS;
246 vt8500_write(port, vt8500_port->ier, VT8500_URIER);
247 }
248
249 static void handle_delta_cts(struct uart_port *port)
250 {
251 port->icount.cts++;
252 wake_up_interruptible(&port->state->port.delta_msr_wait);
253 }
254
255 static irqreturn_t vt8500_irq(int irq, void *dev_id)
256 {
257 struct uart_port *port = dev_id;
258 unsigned long isr;
259
260 spin_lock(&port->lock);
261 isr = vt8500_read(port, VT8500_URISR);
262
263 /* Acknowledge active status bits */
264 vt8500_write(port, isr, VT8500_URISR);
265
266 if (isr & RX_FIFO_INTS)
267 handle_rx(port);
268 if (isr & TX_FIFO_INTS)
269 handle_tx(port);
270 if (isr & TCTS)
271 handle_delta_cts(port);
272
273 spin_unlock(&port->lock);
274
275 return IRQ_HANDLED;
276 }
277
278 static unsigned int vt8500_tx_empty(struct uart_port *port)
279 {
280 return (vt8500_read(port, VT8500_URFIDX) & 0x1f) < 16 ?
281 TIOCSER_TEMT : 0;
282 }
283
284 static unsigned int vt8500_get_mctrl(struct uart_port *port)
285 {
286 unsigned int usr;
287
288 usr = vt8500_read(port, VT8500_URUSR);
289 if (usr & (1 << 4))
290 return TIOCM_CTS;
291 else
292 return 0;
293 }
294
295 static void vt8500_set_mctrl(struct uart_port *port, unsigned int mctrl)
296 {
297 unsigned int lcr = vt8500_read(port, VT8500_URLCR);
298
299 if (mctrl & TIOCM_RTS)
300 lcr |= VT8500_RTS;
301 else
302 lcr &= ~VT8500_RTS;
303
304 vt8500_write(port, lcr, VT8500_URLCR);
305 }
306
307 static void vt8500_break_ctl(struct uart_port *port, int break_ctl)
308 {
309 if (break_ctl)
310 vt8500_write(port,
311 vt8500_read(port, VT8500_URLCR) | VT8500_BREAK,
312 VT8500_URLCR);
313 }
314
315 static int vt8500_set_baud_rate(struct uart_port *port, unsigned int baud)
316 {
317 struct vt8500_port *vt8500_port =
318 container_of(port, struct vt8500_port, uart);
319 unsigned long div;
320 unsigned int loops = 1000;
321
322 div = ((vt8500_port->clk_predivisor - 1) & 0xf) << 16;
323 div |= (uart_get_divisor(port, baud) - 1) & 0x3ff;
324
325 /* Effective baud rate */
326 baud = port->uartclk / 16 / ((div & 0x3ff) + 1);
327
328 while ((vt8500_read(port, VT8500_URUSR) & (1 << 5)) && --loops)
329 cpu_relax();
330
331 vt8500_write(port, div, VT8500_URDIV);
332
333 /* Break signal timing depends on baud rate, update accordingly */
334 vt8500_write(port, mult_frac(baud, 4096, 1000000), VT8500_URBKR);
335
336 return baud;
337 }
338
339 static int vt8500_startup(struct uart_port *port)
340 {
341 struct vt8500_port *vt8500_port =
342 container_of(port, struct vt8500_port, uart);
343 int ret;
344
345 snprintf(vt8500_port->name, sizeof(vt8500_port->name),
346 "vt8500_serial%d", port->line);
347
348 ret = request_irq(port->irq, vt8500_irq, IRQF_TRIGGER_HIGH,
349 vt8500_port->name, port);
350 if (unlikely(ret))
351 return ret;
352
353 vt8500_write(port, 0x03, VT8500_URLCR); /* enable TX & RX */
354
355 return 0;
356 }
357
358 static void vt8500_shutdown(struct uart_port *port)
359 {
360 struct vt8500_port *vt8500_port =
361 container_of(port, struct vt8500_port, uart);
362
363 vt8500_port->ier = 0;
364
365 /* disable interrupts and FIFOs */
366 vt8500_write(&vt8500_port->uart, 0, VT8500_URIER);
367 vt8500_write(&vt8500_port->uart, 0x880, VT8500_URFCR);
368 free_irq(port->irq, port);
369 }
370
371 static void vt8500_set_termios(struct uart_port *port,
372 struct ktermios *termios,
373 struct ktermios *old)
374 {
375 struct vt8500_port *vt8500_port =
376 container_of(port, struct vt8500_port, uart);
377 unsigned long flags;
378 unsigned int baud, lcr;
379 unsigned int loops = 1000;
380
381 spin_lock_irqsave(&port->lock, flags);
382
383 /* calculate and set baud rate */
384 baud = uart_get_baud_rate(port, termios, old, 900, 921600);
385 baud = vt8500_set_baud_rate(port, baud);
386 if (tty_termios_baud_rate(termios))
387 tty_termios_encode_baud_rate(termios, baud, baud);
388
389 /* calculate parity */
390 lcr = vt8500_read(&vt8500_port->uart, VT8500_URLCR);
391 lcr &= ~(VT8500_PARENB | VT8500_PARODD);
392 if (termios->c_cflag & PARENB) {
393 lcr |= VT8500_PARENB;
394 termios->c_cflag &= ~CMSPAR;
395 if (termios->c_cflag & PARODD)
396 lcr |= VT8500_PARODD;
397 }
398
399 /* calculate bits per char */
400 lcr &= ~VT8500_CS8;
401 switch (termios->c_cflag & CSIZE) {
402 case CS7:
403 break;
404 case CS8:
405 default:
406 lcr |= VT8500_CS8;
407 termios->c_cflag &= ~CSIZE;
408 termios->c_cflag |= CS8;
409 break;
410 }
411
412 /* calculate stop bits */
413 lcr &= ~VT8500_CSTOPB;
414 if (termios->c_cflag & CSTOPB)
415 lcr |= VT8500_CSTOPB;
416
417 lcr &= ~VT8500_SWRTSCTS;
418 if (vt8500_port->vt8500_uart_flags & VT8500_HAS_SWRTSCTS_SWITCH)
419 lcr |= VT8500_SWRTSCTS;
420
421 /* set parity, bits per char, and stop bit */
422 vt8500_write(&vt8500_port->uart, lcr, VT8500_URLCR);
423
424 /* Configure status bits to ignore based on termio flags. */
425 port->read_status_mask = 0;
426 if (termios->c_iflag & IGNPAR)
427 port->read_status_mask = FER | PER;
428
429 uart_update_timeout(port, termios->c_cflag, baud);
430
431 /* Reset FIFOs */
432 vt8500_write(&vt8500_port->uart, 0x88c, VT8500_URFCR);
433 while ((vt8500_read(&vt8500_port->uart, VT8500_URFCR) & 0xc)
434 && --loops)
435 cpu_relax();
436
437 /* Every possible FIFO-related interrupt */
438 vt8500_port->ier = RX_FIFO_INTS | TX_FIFO_INTS;
439
440 /*
441 * CTS flow control
442 */
443 if (UART_ENABLE_MS(&vt8500_port->uart, termios->c_cflag))
444 vt8500_port->ier |= TCTS;
445
446 vt8500_write(&vt8500_port->uart, 0x881, VT8500_URFCR);
447 vt8500_write(&vt8500_port->uart, vt8500_port->ier, VT8500_URIER);
448
449 spin_unlock_irqrestore(&port->lock, flags);
450 }
451
452 static const char *vt8500_type(struct uart_port *port)
453 {
454 struct vt8500_port *vt8500_port =
455 container_of(port, struct vt8500_port, uart);
456 return vt8500_port->name;
457 }
458
459 static void vt8500_release_port(struct uart_port *port)
460 {
461 }
462
463 static int vt8500_request_port(struct uart_port *port)
464 {
465 return 0;
466 }
467
468 static void vt8500_config_port(struct uart_port *port, int flags)
469 {
470 port->type = PORT_VT8500;
471 }
472
473 static int vt8500_verify_port(struct uart_port *port,
474 struct serial_struct *ser)
475 {
476 if (unlikely(ser->type != PORT_UNKNOWN && ser->type != PORT_VT8500))
477 return -EINVAL;
478 if (unlikely(port->irq != ser->irq))
479 return -EINVAL;
480 return 0;
481 }
482
483 static struct vt8500_port *vt8500_uart_ports[VT8500_MAX_PORTS];
484 static struct uart_driver vt8500_uart_driver;
485
486 #ifdef CONFIG_SERIAL_VT8500_CONSOLE
487
488 static inline void wait_for_xmitr(struct uart_port *port)
489 {
490 unsigned int status, tmout = 10000;
491
492 /* Wait up to 10ms for the character(s) to be sent. */
493 do {
494 status = vt8500_read(port, VT8500_URFIDX);
495
496 if (--tmout == 0)
497 break;
498 udelay(1);
499 } while (status & 0x10);
500 }
501
502 static void vt8500_console_putchar(struct uart_port *port, int c)
503 {
504 wait_for_xmitr(port);
505 writeb(c, port->membase + VT8500_TXFIFO);
506 }
507
508 static void vt8500_console_write(struct console *co, const char *s,
509 unsigned int count)
510 {
511 struct vt8500_port *vt8500_port = vt8500_uart_ports[co->index];
512 unsigned long ier;
513
514 BUG_ON(co->index < 0 || co->index >= vt8500_uart_driver.nr);
515
516 ier = vt8500_read(&vt8500_port->uart, VT8500_URIER);
517 vt8500_write(&vt8500_port->uart, VT8500_URIER, 0);
518
519 uart_console_write(&vt8500_port->uart, s, count,
520 vt8500_console_putchar);
521
522 /*
523 * Finally, wait for transmitter to become empty
524 * and switch back to FIFO
525 */
526 wait_for_xmitr(&vt8500_port->uart);
527 vt8500_write(&vt8500_port->uart, VT8500_URIER, ier);
528 }
529
530 static int __init vt8500_console_setup(struct console *co, char *options)
531 {
532 struct vt8500_port *vt8500_port;
533 int baud = 9600;
534 int bits = 8;
535 int parity = 'n';
536 int flow = 'n';
537
538 if (unlikely(co->index >= vt8500_uart_driver.nr || co->index < 0))
539 return -ENXIO;
540
541 vt8500_port = vt8500_uart_ports[co->index];
542
543 if (!vt8500_port)
544 return -ENODEV;
545
546 if (options)
547 uart_parse_options(options, &baud, &parity, &bits, &flow);
548
549 return uart_set_options(&vt8500_port->uart,
550 co, baud, parity, bits, flow);
551 }
552
553 static struct console vt8500_console = {
554 .name = "ttyWMT",
555 .write = vt8500_console_write,
556 .device = uart_console_device,
557 .setup = vt8500_console_setup,
558 .flags = CON_PRINTBUFFER,
559 .index = -1,
560 .data = &vt8500_uart_driver,
561 };
562
563 #define VT8500_CONSOLE (&vt8500_console)
564
565 #else
566 #define VT8500_CONSOLE NULL
567 #endif
568
569 #ifdef CONFIG_CONSOLE_POLL
570 static int vt8500_get_poll_char(struct uart_port *port)
571 {
572 unsigned int status = vt8500_read(port, VT8500_URFIDX);
573
574 if (!(status & 0x1f00))
575 return NO_POLL_CHAR;
576
577 return vt8500_read(port, VT8500_RXFIFO) & 0xff;
578 }
579
580 static void vt8500_put_poll_char(struct uart_port *port, unsigned char c)
581 {
582 unsigned int status, tmout = 10000;
583
584 do {
585 status = vt8500_read(port, VT8500_URFIDX);
586
587 if (--tmout == 0)
588 break;
589 udelay(1);
590 } while (status & 0x10);
591
592 vt8500_write(port, c, VT8500_TXFIFO);
593 }
594 #endif
595
596 static struct uart_ops vt8500_uart_pops = {
597 .tx_empty = vt8500_tx_empty,
598 .set_mctrl = vt8500_set_mctrl,
599 .get_mctrl = vt8500_get_mctrl,
600 .stop_tx = vt8500_stop_tx,
601 .start_tx = vt8500_start_tx,
602 .stop_rx = vt8500_stop_rx,
603 .enable_ms = vt8500_enable_ms,
604 .break_ctl = vt8500_break_ctl,
605 .startup = vt8500_startup,
606 .shutdown = vt8500_shutdown,
607 .set_termios = vt8500_set_termios,
608 .type = vt8500_type,
609 .release_port = vt8500_release_port,
610 .request_port = vt8500_request_port,
611 .config_port = vt8500_config_port,
612 .verify_port = vt8500_verify_port,
613 #ifdef CONFIG_CONSOLE_POLL
614 .poll_get_char = vt8500_get_poll_char,
615 .poll_put_char = vt8500_put_poll_char,
616 #endif
617 };
618
619 static struct uart_driver vt8500_uart_driver = {
620 .owner = THIS_MODULE,
621 .driver_name = "vt8500_serial",
622 .dev_name = "ttyWMT",
623 .nr = 6,
624 .cons = VT8500_CONSOLE,
625 };
626
627 static unsigned int vt8500_flags; /* none required so far */
628 static unsigned int wm8880_flags = VT8500_HAS_SWRTSCTS_SWITCH;
629
630 static const struct of_device_id wmt_dt_ids[] = {
631 { .compatible = "via,vt8500-uart", .data = &vt8500_flags},
632 { .compatible = "wm,wm8880-uart", .data = &wm8880_flags},
633 {}
634 };
635
636 static int vt8500_serial_probe(struct platform_device *pdev)
637 {
638 struct vt8500_port *vt8500_port;
639 struct resource *mmres, *irqres;
640 struct device_node *np = pdev->dev.of_node;
641 const struct of_device_id *match;
642 const unsigned int *flags;
643 int ret;
644 int port;
645
646 match = of_match_device(wmt_dt_ids, &pdev->dev);
647 if (!match)
648 return -EINVAL;
649
650 flags = match->data;
651
652 mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
653 irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
654 if (!mmres || !irqres)
655 return -ENODEV;
656
657 if (np) {
658 port = of_alias_get_id(np, "serial");
659 if (port >= VT8500_MAX_PORTS)
660 port = -1;
661 } else {
662 port = -1;
663 }
664
665 if (port < 0) {
666 /* calculate the port id */
667 port = find_first_zero_bit(&vt8500_ports_in_use,
668 sizeof(vt8500_ports_in_use));
669 }
670
671 if (port >= VT8500_MAX_PORTS)
672 return -ENODEV;
673
674 /* reserve the port id */
675 if (test_and_set_bit(port, &vt8500_ports_in_use)) {
676 /* port already in use - shouldn't really happen */
677 return -EBUSY;
678 }
679
680 vt8500_port = devm_kzalloc(&pdev->dev, sizeof(struct vt8500_port),
681 GFP_KERNEL);
682 if (!vt8500_port)
683 return -ENOMEM;
684
685 vt8500_port->uart.membase = devm_ioremap_resource(&pdev->dev, mmres);
686 if (IS_ERR(vt8500_port->uart.membase))
687 return PTR_ERR(vt8500_port->uart.membase);
688
689 vt8500_port->clk = of_clk_get(pdev->dev.of_node, 0);
690 if (IS_ERR(vt8500_port->clk)) {
691 dev_err(&pdev->dev, "failed to get clock\n");
692 return -EINVAL;
693 }
694
695 ret = clk_prepare_enable(vt8500_port->clk);
696 if (ret) {
697 dev_err(&pdev->dev, "failed to enable clock\n");
698 return ret;
699 }
700
701 vt8500_port->vt8500_uart_flags = *flags;
702 vt8500_port->clk_predivisor = DIV_ROUND_CLOSEST(
703 clk_get_rate(vt8500_port->clk),
704 VT8500_RECOMMENDED_CLK
705 );
706 vt8500_port->uart.type = PORT_VT8500;
707 vt8500_port->uart.iotype = UPIO_MEM;
708 vt8500_port->uart.mapbase = mmres->start;
709 vt8500_port->uart.irq = irqres->start;
710 vt8500_port->uart.fifosize = 16;
711 vt8500_port->uart.ops = &vt8500_uart_pops;
712 vt8500_port->uart.line = port;
713 vt8500_port->uart.dev = &pdev->dev;
714 vt8500_port->uart.flags = UPF_IOREMAP | UPF_BOOT_AUTOCONF;
715
716 /* Serial core uses the magic "16" everywhere - adjust for it */
717 vt8500_port->uart.uartclk = 16 * clk_get_rate(vt8500_port->clk) /
718 vt8500_port->clk_predivisor /
719 VT8500_OVERSAMPLING_DIVISOR;
720
721 snprintf(vt8500_port->name, sizeof(vt8500_port->name),
722 "VT8500 UART%d", pdev->id);
723
724 vt8500_uart_ports[port] = vt8500_port;
725
726 uart_add_one_port(&vt8500_uart_driver, &vt8500_port->uart);
727
728 platform_set_drvdata(pdev, vt8500_port);
729
730 return 0;
731 }
732
733 static int vt8500_serial_remove(struct platform_device *pdev)
734 {
735 struct vt8500_port *vt8500_port = platform_get_drvdata(pdev);
736
737 clk_disable_unprepare(vt8500_port->clk);
738 uart_remove_one_port(&vt8500_uart_driver, &vt8500_port->uart);
739
740 return 0;
741 }
742
743 static struct platform_driver vt8500_platform_driver = {
744 .probe = vt8500_serial_probe,
745 .remove = vt8500_serial_remove,
746 .driver = {
747 .name = "vt8500_serial",
748 .of_match_table = wmt_dt_ids,
749 },
750 };
751
752 static int __init vt8500_serial_init(void)
753 {
754 int ret;
755
756 ret = uart_register_driver(&vt8500_uart_driver);
757 if (unlikely(ret))
758 return ret;
759
760 ret = platform_driver_register(&vt8500_platform_driver);
761
762 if (unlikely(ret))
763 uart_unregister_driver(&vt8500_uart_driver);
764
765 return ret;
766 }
767
768 static void __exit vt8500_serial_exit(void)
769 {
770 #ifdef CONFIG_SERIAL_VT8500_CONSOLE
771 unregister_console(&vt8500_console);
772 #endif
773 platform_driver_unregister(&vt8500_platform_driver);
774 uart_unregister_driver(&vt8500_uart_driver);
775 }
776
777 module_init(vt8500_serial_init);
778 module_exit(vt8500_serial_exit);
779
780 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
781 MODULE_DESCRIPTION("Driver for vt8500 serial device");
782 MODULE_LICENSE("GPL v2");
Linux kernel - Deliverables
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