xref: /linux/drivers/tty/serial/8250/8250_mtk.c (revision 8e07e0e3964ca4e23ce7b68e2096fe660a888942)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Mediatek 8250 driver.
4  *
5  * Copyright (c) 2014 MundoReader S.L.
6  * Author: Matthias Brugger <matthias.bgg@gmail.com>
7  */
8 #include <linux/clk.h>
9 #include <linux/io.h>
10 #include <linux/module.h>
11 #include <linux/of_irq.h>
12 #include <linux/of_platform.h>
13 #include <linux/pinctrl/consumer.h>
14 #include <linux/platform_device.h>
15 #include <linux/pm_runtime.h>
16 #include <linux/serial_8250.h>
17 #include <linux/serial_reg.h>
18 #include <linux/console.h>
19 #include <linux/dma-mapping.h>
20 #include <linux/tty.h>
21 #include <linux/tty_flip.h>
22 
23 #include "8250.h"
24 
25 #define MTK_UART_HIGHS		0x09	/* Highspeed register */
26 #define MTK_UART_SAMPLE_COUNT	0x0a	/* Sample count register */
27 #define MTK_UART_SAMPLE_POINT	0x0b	/* Sample point register */
28 #define MTK_UART_RATE_FIX	0x0d	/* UART Rate Fix Register */
29 #define MTK_UART_ESCAPE_DAT	0x10	/* Escape Character register */
30 #define MTK_UART_ESCAPE_EN	0x11	/* Escape Enable register */
31 #define MTK_UART_DMA_EN		0x13	/* DMA Enable register */
32 #define MTK_UART_RXTRI_AD	0x14	/* RX Trigger address */
33 #define MTK_UART_FRACDIV_L	0x15	/* Fractional divider LSB address */
34 #define MTK_UART_FRACDIV_M	0x16	/* Fractional divider MSB address */
35 #define MTK_UART_DEBUG0	0x18
36 #define MTK_UART_IER_XOFFI	0x20	/* Enable XOFF character interrupt */
37 #define MTK_UART_IER_RTSI	0x40	/* Enable RTS Modem status interrupt */
38 #define MTK_UART_IER_CTSI	0x80	/* Enable CTS Modem status interrupt */
39 
40 #define MTK_UART_EFR		38	/* I/O: Extended Features Register */
41 #define MTK_UART_EFR_EN		0x10	/* Enable enhancement feature */
42 #define MTK_UART_EFR_RTS	0x40	/* Enable hardware rx flow control */
43 #define MTK_UART_EFR_CTS	0x80	/* Enable hardware tx flow control */
44 #define MTK_UART_EFR_NO_SW_FC	0x0	/* no sw flow control */
45 #define MTK_UART_EFR_XON1_XOFF1	0xa	/* XON1/XOFF1 as sw flow control */
46 #define MTK_UART_EFR_XON2_XOFF2	0x5	/* XON2/XOFF2 as sw flow control */
47 #define MTK_UART_EFR_SW_FC_MASK	0xf	/* Enable CTS Modem status interrupt */
48 #define MTK_UART_EFR_HW_FC	(MTK_UART_EFR_RTS | MTK_UART_EFR_CTS)
49 #define MTK_UART_DMA_EN_TX	0x2
50 #define MTK_UART_DMA_EN_RX	0x5
51 
52 #define MTK_UART_ESCAPE_CHAR	0x77	/* Escape char added under sw fc */
53 #define MTK_UART_RX_SIZE	0x8000
54 #define MTK_UART_TX_TRIGGER	1
55 #define MTK_UART_RX_TRIGGER	MTK_UART_RX_SIZE
56 
57 #define MTK_UART_XON1		40	/* I/O: Xon character 1 */
58 #define MTK_UART_XOFF1		42	/* I/O: Xoff character 1 */
59 
60 #ifdef CONFIG_SERIAL_8250_DMA
61 enum dma_rx_status {
62 	DMA_RX_START = 0,
63 	DMA_RX_RUNNING = 1,
64 	DMA_RX_SHUTDOWN = 2,
65 };
66 #endif
67 
68 struct mtk8250_data {
69 	int			line;
70 	unsigned int		rx_pos;
71 	unsigned int		clk_count;
72 	struct clk		*uart_clk;
73 	struct clk		*bus_clk;
74 	struct uart_8250_dma	*dma;
75 #ifdef CONFIG_SERIAL_8250_DMA
76 	enum dma_rx_status	rx_status;
77 #endif
78 	int			rx_wakeup_irq;
79 };
80 
81 /* flow control mode */
82 enum {
83 	MTK_UART_FC_NONE,
84 	MTK_UART_FC_SW,
85 	MTK_UART_FC_HW,
86 };
87 
88 #ifdef CONFIG_SERIAL_8250_DMA
89 static void mtk8250_rx_dma(struct uart_8250_port *up);
90 
91 static void mtk8250_dma_rx_complete(void *param)
92 {
93 	struct uart_8250_port *up = param;
94 	struct uart_8250_dma *dma = up->dma;
95 	struct mtk8250_data *data = up->port.private_data;
96 	struct tty_port *tty_port = &up->port.state->port;
97 	struct dma_tx_state state;
98 	int copied, total, cnt;
99 	unsigned char *ptr;
100 	unsigned long flags;
101 
102 	if (data->rx_status == DMA_RX_SHUTDOWN)
103 		return;
104 
105 	uart_port_lock_irqsave(&up->port, &flags);
106 
107 	dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
108 	total = dma->rx_size - state.residue;
109 	cnt = total;
110 
111 	if ((data->rx_pos + cnt) > dma->rx_size)
112 		cnt = dma->rx_size - data->rx_pos;
113 
114 	ptr = (unsigned char *)(data->rx_pos + dma->rx_buf);
115 	copied = tty_insert_flip_string(tty_port, ptr, cnt);
116 	data->rx_pos += cnt;
117 
118 	if (total > cnt) {
119 		ptr = (unsigned char *)(dma->rx_buf);
120 		cnt = total - cnt;
121 		copied += tty_insert_flip_string(tty_port, ptr, cnt);
122 		data->rx_pos = cnt;
123 	}
124 
125 	up->port.icount.rx += copied;
126 
127 	tty_flip_buffer_push(tty_port);
128 
129 	mtk8250_rx_dma(up);
130 
131 	uart_port_unlock_irqrestore(&up->port, flags);
132 }
133 
134 static void mtk8250_rx_dma(struct uart_8250_port *up)
135 {
136 	struct uart_8250_dma *dma = up->dma;
137 	struct dma_async_tx_descriptor	*desc;
138 
139 	desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr,
140 					   dma->rx_size, DMA_DEV_TO_MEM,
141 					   DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
142 	if (!desc) {
143 		pr_err("failed to prepare rx slave single\n");
144 		return;
145 	}
146 
147 	desc->callback = mtk8250_dma_rx_complete;
148 	desc->callback_param = up;
149 
150 	dma->rx_cookie = dmaengine_submit(desc);
151 
152 	dma_async_issue_pending(dma->rxchan);
153 }
154 
155 static void mtk8250_dma_enable(struct uart_8250_port *up)
156 {
157 	struct uart_8250_dma *dma = up->dma;
158 	struct mtk8250_data *data = up->port.private_data;
159 	int lcr = serial_in(up, UART_LCR);
160 
161 	if (data->rx_status != DMA_RX_START)
162 		return;
163 
164 	dma->rxconf.src_port_window_size	= dma->rx_size;
165 	dma->rxconf.src_addr				= dma->rx_addr;
166 
167 	dma->txconf.dst_port_window_size	= UART_XMIT_SIZE;
168 	dma->txconf.dst_addr				= dma->tx_addr;
169 
170 	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR |
171 		UART_FCR_CLEAR_XMIT);
172 	serial_out(up, MTK_UART_DMA_EN,
173 		   MTK_UART_DMA_EN_RX | MTK_UART_DMA_EN_TX);
174 
175 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
176 	serial_out(up, MTK_UART_EFR, UART_EFR_ECB);
177 	serial_out(up, UART_LCR, lcr);
178 
179 	if (dmaengine_slave_config(dma->rxchan, &dma->rxconf) != 0)
180 		pr_err("failed to configure rx dma channel\n");
181 	if (dmaengine_slave_config(dma->txchan, &dma->txconf) != 0)
182 		pr_err("failed to configure tx dma channel\n");
183 
184 	data->rx_status = DMA_RX_RUNNING;
185 	data->rx_pos = 0;
186 	mtk8250_rx_dma(up);
187 }
188 #endif
189 
190 static int mtk8250_startup(struct uart_port *port)
191 {
192 #ifdef CONFIG_SERIAL_8250_DMA
193 	struct uart_8250_port *up = up_to_u8250p(port);
194 	struct mtk8250_data *data = port->private_data;
195 
196 	/* disable DMA for console */
197 	if (uart_console(port))
198 		up->dma = NULL;
199 
200 	if (up->dma) {
201 		data->rx_status = DMA_RX_START;
202 		uart_circ_clear(&port->state->xmit);
203 	}
204 #endif
205 	memset(&port->icount, 0, sizeof(port->icount));
206 
207 	return serial8250_do_startup(port);
208 }
209 
210 static void mtk8250_shutdown(struct uart_port *port)
211 {
212 #ifdef CONFIG_SERIAL_8250_DMA
213 	struct uart_8250_port *up = up_to_u8250p(port);
214 	struct mtk8250_data *data = port->private_data;
215 
216 	if (up->dma)
217 		data->rx_status = DMA_RX_SHUTDOWN;
218 #endif
219 
220 	return serial8250_do_shutdown(port);
221 }
222 
223 static void mtk8250_disable_intrs(struct uart_8250_port *up, int mask)
224 {
225 	/* Port locked to synchronize UART_IER access against the console. */
226 	lockdep_assert_held_once(&up->port.lock);
227 
228 	serial_out(up, UART_IER, serial_in(up, UART_IER) & (~mask));
229 }
230 
231 static void mtk8250_enable_intrs(struct uart_8250_port *up, int mask)
232 {
233 	/* Port locked to synchronize UART_IER access against the console. */
234 	lockdep_assert_held_once(&up->port.lock);
235 
236 	serial_out(up, UART_IER, serial_in(up, UART_IER) | mask);
237 }
238 
239 static void mtk8250_set_flow_ctrl(struct uart_8250_port *up, int mode)
240 {
241 	struct uart_port *port = &up->port;
242 	int lcr = serial_in(up, UART_LCR);
243 
244 	/* Port locked to synchronize UART_IER access against the console. */
245 	lockdep_assert_held_once(&port->lock);
246 
247 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
248 	serial_out(up, MTK_UART_EFR, UART_EFR_ECB);
249 	serial_out(up, UART_LCR, lcr);
250 	lcr = serial_in(up, UART_LCR);
251 
252 	switch (mode) {
253 	case MTK_UART_FC_NONE:
254 		serial_out(up, MTK_UART_ESCAPE_DAT, MTK_UART_ESCAPE_CHAR);
255 		serial_out(up, MTK_UART_ESCAPE_EN, 0x00);
256 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
257 		serial_out(up, MTK_UART_EFR, serial_in(up, MTK_UART_EFR) &
258 			(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK)));
259 		serial_out(up, UART_LCR, lcr);
260 		mtk8250_disable_intrs(up, MTK_UART_IER_XOFFI |
261 			MTK_UART_IER_RTSI | MTK_UART_IER_CTSI);
262 		break;
263 
264 	case MTK_UART_FC_HW:
265 		serial_out(up, MTK_UART_ESCAPE_DAT, MTK_UART_ESCAPE_CHAR);
266 		serial_out(up, MTK_UART_ESCAPE_EN, 0x00);
267 		serial_out(up, UART_MCR, UART_MCR_RTS);
268 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
269 
270 		/*enable hw flow control*/
271 		serial_out(up, MTK_UART_EFR, MTK_UART_EFR_HW_FC |
272 			(serial_in(up, MTK_UART_EFR) &
273 			(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK))));
274 
275 		serial_out(up, UART_LCR, lcr);
276 		mtk8250_disable_intrs(up, MTK_UART_IER_XOFFI);
277 		mtk8250_enable_intrs(up, MTK_UART_IER_CTSI | MTK_UART_IER_RTSI);
278 		break;
279 
280 	case MTK_UART_FC_SW:	/*MTK software flow control */
281 		serial_out(up, MTK_UART_ESCAPE_DAT, MTK_UART_ESCAPE_CHAR);
282 		serial_out(up, MTK_UART_ESCAPE_EN, 0x01);
283 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
284 
285 		/*enable sw flow control */
286 		serial_out(up, MTK_UART_EFR, MTK_UART_EFR_XON1_XOFF1 |
287 			(serial_in(up, MTK_UART_EFR) &
288 			(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK))));
289 
290 		serial_out(up, MTK_UART_XON1, START_CHAR(port->state->port.tty));
291 		serial_out(up, MTK_UART_XOFF1, STOP_CHAR(port->state->port.tty));
292 		serial_out(up, UART_LCR, lcr);
293 		mtk8250_disable_intrs(up, MTK_UART_IER_CTSI|MTK_UART_IER_RTSI);
294 		mtk8250_enable_intrs(up, MTK_UART_IER_XOFFI);
295 		break;
296 	default:
297 		break;
298 	}
299 }
300 
301 static void
302 mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
303 		    const struct ktermios *old)
304 {
305 	static const unsigned short fraction_L_mapping[] = {
306 		0, 1, 0x5, 0x15, 0x55, 0x57, 0x57, 0x77, 0x7F, 0xFF, 0xFF
307 	};
308 	static const unsigned short fraction_M_mapping[] = {
309 		0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 3
310 	};
311 	struct uart_8250_port *up = up_to_u8250p(port);
312 	unsigned int baud, quot, fraction;
313 	unsigned long flags;
314 	int mode;
315 
316 #ifdef CONFIG_SERIAL_8250_DMA
317 	if (up->dma) {
318 		if (uart_console(port)) {
319 			devm_kfree(up->port.dev, up->dma);
320 			up->dma = NULL;
321 		} else {
322 			mtk8250_dma_enable(up);
323 		}
324 	}
325 #endif
326 
327 	/*
328 	 * Store the requested baud rate before calling the generic 8250
329 	 * set_termios method. Standard 8250 port expects bauds to be
330 	 * no higher than (uartclk / 16) so the baud will be clamped if it
331 	 * gets out of that bound. Mediatek 8250 port supports speed
332 	 * higher than that, therefore we'll get original baud rate back
333 	 * after calling the generic set_termios method and recalculate
334 	 * the speed later in this method.
335 	 */
336 	baud = tty_termios_baud_rate(termios);
337 
338 	serial8250_do_set_termios(port, termios, NULL);
339 
340 	tty_termios_encode_baud_rate(termios, baud, baud);
341 
342 	/*
343 	 * Mediatek UARTs use an extra highspeed register (MTK_UART_HIGHS)
344 	 *
345 	 * We need to recalcualte the quot register, as the claculation depends
346 	 * on the vaule in the highspeed register.
347 	 *
348 	 * Some baudrates are not supported by the chip, so we use the next
349 	 * lower rate supported and update termios c_flag.
350 	 *
351 	 * If highspeed register is set to 3, we need to specify sample count
352 	 * and sample point to increase accuracy. If not, we reset the
353 	 * registers to their default values.
354 	 */
355 	baud = uart_get_baud_rate(port, termios, old,
356 				  port->uartclk / 16 / UART_DIV_MAX,
357 				  port->uartclk);
358 
359 	if (baud < 115200) {
360 		serial_port_out(port, MTK_UART_HIGHS, 0x0);
361 		quot = uart_get_divisor(port, baud);
362 	} else {
363 		serial_port_out(port, MTK_UART_HIGHS, 0x3);
364 		quot = DIV_ROUND_UP(port->uartclk, 256 * baud);
365 	}
366 
367 	/*
368 	 * Ok, we're now changing the port state.  Do it with
369 	 * interrupts disabled.
370 	 */
371 	uart_port_lock_irqsave(port, &flags);
372 
373 	/*
374 	 * Update the per-port timeout.
375 	 */
376 	uart_update_timeout(port, termios->c_cflag, baud);
377 
378 	/* set DLAB we have cval saved in up->lcr from the call to the core */
379 	serial_port_out(port, UART_LCR, up->lcr | UART_LCR_DLAB);
380 	serial_dl_write(up, quot);
381 
382 	/* reset DLAB */
383 	serial_port_out(port, UART_LCR, up->lcr);
384 
385 	if (baud >= 115200) {
386 		unsigned int tmp;
387 
388 		tmp = (port->uartclk / (baud *  quot)) - 1;
389 		serial_port_out(port, MTK_UART_SAMPLE_COUNT, tmp);
390 		serial_port_out(port, MTK_UART_SAMPLE_POINT,
391 					(tmp >> 1) - 1);
392 
393 		/*count fraction to set fractoin register */
394 		fraction = ((port->uartclk  * 100) / baud / quot) % 100;
395 		fraction = DIV_ROUND_CLOSEST(fraction, 10);
396 		serial_port_out(port, MTK_UART_FRACDIV_L,
397 						fraction_L_mapping[fraction]);
398 		serial_port_out(port, MTK_UART_FRACDIV_M,
399 						fraction_M_mapping[fraction]);
400 	} else {
401 		serial_port_out(port, MTK_UART_SAMPLE_COUNT, 0x00);
402 		serial_port_out(port, MTK_UART_SAMPLE_POINT, 0xff);
403 		serial_port_out(port, MTK_UART_FRACDIV_L, 0x00);
404 		serial_port_out(port, MTK_UART_FRACDIV_M, 0x00);
405 	}
406 
407 	if ((termios->c_cflag & CRTSCTS) && (!(termios->c_iflag & CRTSCTS)))
408 		mode = MTK_UART_FC_HW;
409 	else if (termios->c_iflag & CRTSCTS)
410 		mode = MTK_UART_FC_SW;
411 	else
412 		mode = MTK_UART_FC_NONE;
413 
414 	mtk8250_set_flow_ctrl(up, mode);
415 
416 	if (uart_console(port))
417 		up->port.cons->cflag = termios->c_cflag;
418 
419 	uart_port_unlock_irqrestore(port, flags);
420 	/* Don't rewrite B0 */
421 	if (tty_termios_baud_rate(termios))
422 		tty_termios_encode_baud_rate(termios, baud, baud);
423 }
424 
425 static int __maybe_unused mtk8250_runtime_suspend(struct device *dev)
426 {
427 	struct mtk8250_data *data = dev_get_drvdata(dev);
428 	struct uart_8250_port *up = serial8250_get_port(data->line);
429 
430 	/* wait until UART in idle status */
431 	while
432 		(serial_in(up, MTK_UART_DEBUG0));
433 
434 	clk_disable_unprepare(data->bus_clk);
435 
436 	return 0;
437 }
438 
439 static int __maybe_unused mtk8250_runtime_resume(struct device *dev)
440 {
441 	struct mtk8250_data *data = dev_get_drvdata(dev);
442 
443 	clk_prepare_enable(data->bus_clk);
444 
445 	return 0;
446 }
447 
448 static void
449 mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
450 {
451 	if (!state)
452 		pm_runtime_get_sync(port->dev);
453 
454 	serial8250_do_pm(port, state, old);
455 
456 	if (state)
457 		pm_runtime_put_sync_suspend(port->dev);
458 }
459 
460 #ifdef CONFIG_SERIAL_8250_DMA
461 static bool mtk8250_dma_filter(struct dma_chan *chan, void *param)
462 {
463 	return false;
464 }
465 #endif
466 
467 static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p,
468 			   struct mtk8250_data *data)
469 {
470 #ifdef CONFIG_SERIAL_8250_DMA
471 	int dmacnt;
472 #endif
473 
474 	data->uart_clk = devm_clk_get(&pdev->dev, "baud");
475 	if (IS_ERR(data->uart_clk)) {
476 		/*
477 		 * For compatibility with older device trees try unnamed
478 		 * clk when no baud clk can be found.
479 		 */
480 		data->uart_clk = devm_clk_get(&pdev->dev, NULL);
481 		if (IS_ERR(data->uart_clk)) {
482 			dev_warn(&pdev->dev, "Can't get uart clock\n");
483 			return PTR_ERR(data->uart_clk);
484 		}
485 
486 		return 0;
487 	}
488 
489 	data->bus_clk = devm_clk_get_enabled(&pdev->dev, "bus");
490 	if (IS_ERR(data->bus_clk))
491 		return PTR_ERR(data->bus_clk);
492 
493 	data->dma = NULL;
494 #ifdef CONFIG_SERIAL_8250_DMA
495 	dmacnt = of_property_count_strings(pdev->dev.of_node, "dma-names");
496 	if (dmacnt == 2) {
497 		data->dma = devm_kzalloc(&pdev->dev, sizeof(*data->dma),
498 					 GFP_KERNEL);
499 		if (!data->dma)
500 			return -ENOMEM;
501 
502 		data->dma->fn = mtk8250_dma_filter;
503 		data->dma->rx_size = MTK_UART_RX_SIZE;
504 		data->dma->rxconf.src_maxburst = MTK_UART_RX_TRIGGER;
505 		data->dma->txconf.dst_maxburst = MTK_UART_TX_TRIGGER;
506 	}
507 #endif
508 
509 	return 0;
510 }
511 
512 static int mtk8250_probe(struct platform_device *pdev)
513 {
514 	struct uart_8250_port uart = {};
515 	struct mtk8250_data *data;
516 	struct resource *regs;
517 	int irq, err;
518 
519 	irq = platform_get_irq(pdev, 0);
520 	if (irq < 0)
521 		return irq;
522 
523 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
524 	if (!regs) {
525 		dev_err(&pdev->dev, "no registers defined\n");
526 		return -EINVAL;
527 	}
528 
529 	uart.port.membase = devm_ioremap(&pdev->dev, regs->start,
530 					 resource_size(regs));
531 	if (!uart.port.membase)
532 		return -ENOMEM;
533 
534 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
535 	if (!data)
536 		return -ENOMEM;
537 
538 	data->clk_count = 0;
539 
540 	if (pdev->dev.of_node) {
541 		err = mtk8250_probe_of(pdev, &uart.port, data);
542 		if (err)
543 			return err;
544 	} else
545 		return -ENODEV;
546 
547 	spin_lock_init(&uart.port.lock);
548 	uart.port.mapbase = regs->start;
549 	uart.port.irq = irq;
550 	uart.port.pm = mtk8250_do_pm;
551 	uart.port.type = PORT_16550;
552 	uart.port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
553 	uart.port.dev = &pdev->dev;
554 	uart.port.iotype = UPIO_MEM32;
555 	uart.port.regshift = 2;
556 	uart.port.private_data = data;
557 	uart.port.shutdown = mtk8250_shutdown;
558 	uart.port.startup = mtk8250_startup;
559 	uart.port.set_termios = mtk8250_set_termios;
560 	uart.port.uartclk = clk_get_rate(data->uart_clk);
561 #ifdef CONFIG_SERIAL_8250_DMA
562 	if (data->dma)
563 		uart.dma = data->dma;
564 #endif
565 
566 	/* Disable Rate Fix function */
567 	writel(0x0, uart.port.membase +
568 			(MTK_UART_RATE_FIX << uart.port.regshift));
569 
570 	platform_set_drvdata(pdev, data);
571 
572 	data->line = serial8250_register_8250_port(&uart);
573 	if (data->line < 0)
574 		return data->line;
575 
576 	data->rx_wakeup_irq = platform_get_irq_optional(pdev, 1);
577 
578 	pm_runtime_set_active(&pdev->dev);
579 	pm_runtime_enable(&pdev->dev);
580 
581 	return 0;
582 }
583 
584 static int mtk8250_remove(struct platform_device *pdev)
585 {
586 	struct mtk8250_data *data = platform_get_drvdata(pdev);
587 
588 	pm_runtime_get_sync(&pdev->dev);
589 
590 	serial8250_unregister_port(data->line);
591 
592 	pm_runtime_disable(&pdev->dev);
593 	pm_runtime_put_noidle(&pdev->dev);
594 
595 	return 0;
596 }
597 
598 static int __maybe_unused mtk8250_suspend(struct device *dev)
599 {
600 	struct mtk8250_data *data = dev_get_drvdata(dev);
601 	int irq = data->rx_wakeup_irq;
602 	int err;
603 
604 	serial8250_suspend_port(data->line);
605 
606 	pinctrl_pm_select_sleep_state(dev);
607 	if (irq >= 0) {
608 		err = enable_irq_wake(irq);
609 		if (err) {
610 			dev_err(dev,
611 				"failed to enable irq wake on IRQ %d: %d\n",
612 				irq, err);
613 			pinctrl_pm_select_default_state(dev);
614 			serial8250_resume_port(data->line);
615 			return err;
616 		}
617 	}
618 
619 	return 0;
620 }
621 
622 static int __maybe_unused mtk8250_resume(struct device *dev)
623 {
624 	struct mtk8250_data *data = dev_get_drvdata(dev);
625 	int irq = data->rx_wakeup_irq;
626 
627 	if (irq >= 0)
628 		disable_irq_wake(irq);
629 	pinctrl_pm_select_default_state(dev);
630 
631 	serial8250_resume_port(data->line);
632 
633 	return 0;
634 }
635 
636 static const struct dev_pm_ops mtk8250_pm_ops = {
637 	SET_SYSTEM_SLEEP_PM_OPS(mtk8250_suspend, mtk8250_resume)
638 	SET_RUNTIME_PM_OPS(mtk8250_runtime_suspend, mtk8250_runtime_resume,
639 				NULL)
640 };
641 
642 static const struct of_device_id mtk8250_of_match[] = {
643 	{ .compatible = "mediatek,mt6577-uart" },
644 	{ /* Sentinel */ }
645 };
646 MODULE_DEVICE_TABLE(of, mtk8250_of_match);
647 
648 static struct platform_driver mtk8250_platform_driver = {
649 	.driver = {
650 		.name		= "mt6577-uart",
651 		.pm		= &mtk8250_pm_ops,
652 		.of_match_table	= mtk8250_of_match,
653 	},
654 	.probe			= mtk8250_probe,
655 	.remove			= mtk8250_remove,
656 };
657 module_platform_driver(mtk8250_platform_driver);
658 
659 #ifdef CONFIG_SERIAL_8250_CONSOLE
660 static int __init early_mtk8250_setup(struct earlycon_device *device,
661 					const char *options)
662 {
663 	if (!device->port.membase)
664 		return -ENODEV;
665 
666 	device->port.iotype = UPIO_MEM32;
667 	device->port.regshift = 2;
668 
669 	return early_serial8250_setup(device, NULL);
670 }
671 
672 OF_EARLYCON_DECLARE(mtk8250, "mediatek,mt6577-uart", early_mtk8250_setup);
673 #endif
674 
675 MODULE_AUTHOR("Matthias Brugger");
676 MODULE_LICENSE("GPL");
677 MODULE_DESCRIPTION("Mediatek 8250 serial port driver");
678