xref: /openbmc/linux/drivers/tty/serial/8250/8250_mtk.c (revision 6f4eaea2)
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_EN		0x10	/* Enable enhancement feature */
41 #define MTK_UART_EFR_RTS	0x40	/* Enable hardware rx flow control */
42 #define MTK_UART_EFR_CTS	0x80	/* Enable hardware tx flow control */
43 #define MTK_UART_EFR_NO_SW_FC	0x0	/* no sw flow control */
44 #define MTK_UART_EFR_XON1_XOFF1	0xa	/* XON1/XOFF1 as sw flow control */
45 #define MTK_UART_EFR_XON2_XOFF2	0x5	/* XON2/XOFF2 as sw flow control */
46 #define MTK_UART_EFR_SW_FC_MASK	0xf	/* Enable CTS Modem status interrupt */
47 #define MTK_UART_EFR_HW_FC	(MTK_UART_EFR_RTS | MTK_UART_EFR_CTS)
48 #define MTK_UART_DMA_EN_TX	0x2
49 #define MTK_UART_DMA_EN_RX	0x5
50 
51 #define MTK_UART_ESCAPE_CHAR	0x77	/* Escape char added under sw fc */
52 #define MTK_UART_RX_SIZE	0x8000
53 #define MTK_UART_TX_TRIGGER	1
54 #define MTK_UART_RX_TRIGGER	MTK_UART_RX_SIZE
55 
56 #ifdef CONFIG_SERIAL_8250_DMA
57 enum dma_rx_status {
58 	DMA_RX_START = 0,
59 	DMA_RX_RUNNING = 1,
60 	DMA_RX_SHUTDOWN = 2,
61 };
62 #endif
63 
64 struct mtk8250_data {
65 	int			line;
66 	unsigned int		rx_pos;
67 	unsigned int		clk_count;
68 	struct clk		*uart_clk;
69 	struct clk		*bus_clk;
70 	struct uart_8250_dma	*dma;
71 #ifdef CONFIG_SERIAL_8250_DMA
72 	enum dma_rx_status	rx_status;
73 #endif
74 	int			rx_wakeup_irq;
75 };
76 
77 /* flow control mode */
78 enum {
79 	MTK_UART_FC_NONE,
80 	MTK_UART_FC_SW,
81 	MTK_UART_FC_HW,
82 };
83 
84 #ifdef CONFIG_SERIAL_8250_DMA
85 static void mtk8250_rx_dma(struct uart_8250_port *up);
86 
87 static void mtk8250_dma_rx_complete(void *param)
88 {
89 	struct uart_8250_port *up = param;
90 	struct uart_8250_dma *dma = up->dma;
91 	struct mtk8250_data *data = up->port.private_data;
92 	struct tty_port *tty_port = &up->port.state->port;
93 	struct dma_tx_state state;
94 	int copied, total, cnt;
95 	unsigned char *ptr;
96 
97 	if (data->rx_status == DMA_RX_SHUTDOWN)
98 		return;
99 
100 	dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
101 	total = dma->rx_size - state.residue;
102 	cnt = total;
103 
104 	if ((data->rx_pos + cnt) > dma->rx_size)
105 		cnt = dma->rx_size - data->rx_pos;
106 
107 	ptr = (unsigned char *)(data->rx_pos + dma->rx_buf);
108 	copied = tty_insert_flip_string(tty_port, ptr, cnt);
109 	data->rx_pos += cnt;
110 
111 	if (total > cnt) {
112 		ptr = (unsigned char *)(dma->rx_buf);
113 		cnt = total - cnt;
114 		copied += tty_insert_flip_string(tty_port, ptr, cnt);
115 		data->rx_pos = cnt;
116 	}
117 
118 	up->port.icount.rx += copied;
119 
120 	tty_flip_buffer_push(tty_port);
121 
122 	mtk8250_rx_dma(up);
123 }
124 
125 static void mtk8250_rx_dma(struct uart_8250_port *up)
126 {
127 	struct uart_8250_dma *dma = up->dma;
128 	struct dma_async_tx_descriptor	*desc;
129 
130 	desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr,
131 					   dma->rx_size, DMA_DEV_TO_MEM,
132 					   DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
133 	if (!desc) {
134 		pr_err("failed to prepare rx slave single\n");
135 		return;
136 	}
137 
138 	desc->callback = mtk8250_dma_rx_complete;
139 	desc->callback_param = up;
140 
141 	dma->rx_cookie = dmaengine_submit(desc);
142 
143 	dma_async_issue_pending(dma->rxchan);
144 }
145 
146 static void mtk8250_dma_enable(struct uart_8250_port *up)
147 {
148 	struct uart_8250_dma *dma = up->dma;
149 	struct mtk8250_data *data = up->port.private_data;
150 	int lcr = serial_in(up, UART_LCR);
151 
152 	if (data->rx_status != DMA_RX_START)
153 		return;
154 
155 	dma->rxconf.src_port_window_size	= dma->rx_size;
156 	dma->rxconf.src_addr				= dma->rx_addr;
157 
158 	dma->txconf.dst_port_window_size	= UART_XMIT_SIZE;
159 	dma->txconf.dst_addr				= dma->tx_addr;
160 
161 	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR |
162 		UART_FCR_CLEAR_XMIT);
163 	serial_out(up, MTK_UART_DMA_EN,
164 		   MTK_UART_DMA_EN_RX | MTK_UART_DMA_EN_TX);
165 
166 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
167 	serial_out(up, UART_EFR, UART_EFR_ECB);
168 	serial_out(up, UART_LCR, lcr);
169 
170 	if (dmaengine_slave_config(dma->rxchan, &dma->rxconf) != 0)
171 		pr_err("failed to configure rx dma channel\n");
172 	if (dmaengine_slave_config(dma->txchan, &dma->txconf) != 0)
173 		pr_err("failed to configure tx dma channel\n");
174 
175 	data->rx_status = DMA_RX_RUNNING;
176 	data->rx_pos = 0;
177 	mtk8250_rx_dma(up);
178 }
179 #endif
180 
181 static int mtk8250_startup(struct uart_port *port)
182 {
183 #ifdef CONFIG_SERIAL_8250_DMA
184 	struct uart_8250_port *up = up_to_u8250p(port);
185 	struct mtk8250_data *data = port->private_data;
186 
187 	/* disable DMA for console */
188 	if (uart_console(port))
189 		up->dma = NULL;
190 
191 	if (up->dma) {
192 		data->rx_status = DMA_RX_START;
193 		uart_circ_clear(&port->state->xmit);
194 	}
195 #endif
196 	memset(&port->icount, 0, sizeof(port->icount));
197 
198 	return serial8250_do_startup(port);
199 }
200 
201 static void mtk8250_shutdown(struct uart_port *port)
202 {
203 #ifdef CONFIG_SERIAL_8250_DMA
204 	struct uart_8250_port *up = up_to_u8250p(port);
205 	struct mtk8250_data *data = port->private_data;
206 
207 	if (up->dma)
208 		data->rx_status = DMA_RX_SHUTDOWN;
209 #endif
210 
211 	return serial8250_do_shutdown(port);
212 }
213 
214 static void mtk8250_disable_intrs(struct uart_8250_port *up, int mask)
215 {
216 	serial_out(up, UART_IER, serial_in(up, UART_IER) & (~mask));
217 }
218 
219 static void mtk8250_enable_intrs(struct uart_8250_port *up, int mask)
220 {
221 	serial_out(up, UART_IER, serial_in(up, UART_IER) | mask);
222 }
223 
224 static void mtk8250_set_flow_ctrl(struct uart_8250_port *up, int mode)
225 {
226 	struct uart_port *port = &up->port;
227 	int lcr = serial_in(up, UART_LCR);
228 
229 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
230 	serial_out(up, UART_EFR, UART_EFR_ECB);
231 	serial_out(up, UART_LCR, lcr);
232 	lcr = serial_in(up, UART_LCR);
233 
234 	switch (mode) {
235 	case MTK_UART_FC_NONE:
236 		serial_out(up, MTK_UART_ESCAPE_DAT, MTK_UART_ESCAPE_CHAR);
237 		serial_out(up, MTK_UART_ESCAPE_EN, 0x00);
238 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
239 		serial_out(up, UART_EFR, serial_in(up, UART_EFR) &
240 			(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK)));
241 		serial_out(up, UART_LCR, lcr);
242 		mtk8250_disable_intrs(up, MTK_UART_IER_XOFFI |
243 			MTK_UART_IER_RTSI | MTK_UART_IER_CTSI);
244 		break;
245 
246 	case MTK_UART_FC_HW:
247 		serial_out(up, MTK_UART_ESCAPE_DAT, MTK_UART_ESCAPE_CHAR);
248 		serial_out(up, MTK_UART_ESCAPE_EN, 0x00);
249 		serial_out(up, UART_MCR, UART_MCR_RTS);
250 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
251 
252 		/*enable hw flow control*/
253 		serial_out(up, UART_EFR, MTK_UART_EFR_HW_FC |
254 			(serial_in(up, UART_EFR) &
255 			(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK))));
256 
257 		serial_out(up, UART_LCR, lcr);
258 		mtk8250_disable_intrs(up, MTK_UART_IER_XOFFI);
259 		mtk8250_enable_intrs(up, MTK_UART_IER_CTSI | MTK_UART_IER_RTSI);
260 		break;
261 
262 	case MTK_UART_FC_SW:	/*MTK software flow control */
263 		serial_out(up, MTK_UART_ESCAPE_DAT, MTK_UART_ESCAPE_CHAR);
264 		serial_out(up, MTK_UART_ESCAPE_EN, 0x01);
265 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
266 
267 		/*enable sw flow control */
268 		serial_out(up, UART_EFR, MTK_UART_EFR_XON1_XOFF1 |
269 			(serial_in(up, UART_EFR) &
270 			(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK))));
271 
272 		serial_out(up, UART_XON1, START_CHAR(port->state->port.tty));
273 		serial_out(up, UART_XOFF1, STOP_CHAR(port->state->port.tty));
274 		serial_out(up, UART_LCR, lcr);
275 		mtk8250_disable_intrs(up, MTK_UART_IER_CTSI|MTK_UART_IER_RTSI);
276 		mtk8250_enable_intrs(up, MTK_UART_IER_XOFFI);
277 		break;
278 	default:
279 		break;
280 	}
281 }
282 
283 static void
284 mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
285 			struct ktermios *old)
286 {
287 	unsigned short fraction_L_mapping[] = {
288 		0, 1, 0x5, 0x15, 0x55, 0x57, 0x57, 0x77, 0x7F, 0xFF, 0xFF
289 	};
290 	unsigned short fraction_M_mapping[] = {
291 		0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 3
292 	};
293 	struct uart_8250_port *up = up_to_u8250p(port);
294 	unsigned int baud, quot, fraction;
295 	unsigned long flags;
296 	int mode;
297 
298 #ifdef CONFIG_SERIAL_8250_DMA
299 	if (up->dma) {
300 		if (uart_console(port)) {
301 			devm_kfree(up->port.dev, up->dma);
302 			up->dma = NULL;
303 		} else {
304 			mtk8250_dma_enable(up);
305 		}
306 	}
307 #endif
308 
309 	/*
310 	 * Store the requested baud rate before calling the generic 8250
311 	 * set_termios method. Standard 8250 port expects bauds to be
312 	 * no higher than (uartclk / 16) so the baud will be clamped if it
313 	 * gets out of that bound. Mediatek 8250 port supports speed
314 	 * higher than that, therefore we'll get original baud rate back
315 	 * after calling the generic set_termios method and recalculate
316 	 * the speed later in this method.
317 	 */
318 	baud = tty_termios_baud_rate(termios);
319 
320 	serial8250_do_set_termios(port, termios, NULL);
321 
322 	tty_termios_encode_baud_rate(termios, baud, baud);
323 
324 	/*
325 	 * Mediatek UARTs use an extra highspeed register (MTK_UART_HIGHS)
326 	 *
327 	 * We need to recalcualte the quot register, as the claculation depends
328 	 * on the vaule in the highspeed register.
329 	 *
330 	 * Some baudrates are not supported by the chip, so we use the next
331 	 * lower rate supported and update termios c_flag.
332 	 *
333 	 * If highspeed register is set to 3, we need to specify sample count
334 	 * and sample point to increase accuracy. If not, we reset the
335 	 * registers to their default values.
336 	 */
337 	baud = uart_get_baud_rate(port, termios, old,
338 				  port->uartclk / 16 / UART_DIV_MAX,
339 				  port->uartclk);
340 
341 	if (baud < 115200) {
342 		serial_port_out(port, MTK_UART_HIGHS, 0x0);
343 		quot = uart_get_divisor(port, baud);
344 	} else {
345 		serial_port_out(port, MTK_UART_HIGHS, 0x3);
346 		quot = DIV_ROUND_UP(port->uartclk, 256 * baud);
347 	}
348 
349 	/*
350 	 * Ok, we're now changing the port state.  Do it with
351 	 * interrupts disabled.
352 	 */
353 	spin_lock_irqsave(&port->lock, flags);
354 
355 	/*
356 	 * Update the per-port timeout.
357 	 */
358 	uart_update_timeout(port, termios->c_cflag, baud);
359 
360 	/* set DLAB we have cval saved in up->lcr from the call to the core */
361 	serial_port_out(port, UART_LCR, up->lcr | UART_LCR_DLAB);
362 	serial_dl_write(up, quot);
363 
364 	/* reset DLAB */
365 	serial_port_out(port, UART_LCR, up->lcr);
366 
367 	if (baud >= 115200) {
368 		unsigned int tmp;
369 
370 		tmp = (port->uartclk / (baud *  quot)) - 1;
371 		serial_port_out(port, MTK_UART_SAMPLE_COUNT, tmp);
372 		serial_port_out(port, MTK_UART_SAMPLE_POINT,
373 					(tmp >> 1) - 1);
374 
375 		/*count fraction to set fractoin register */
376 		fraction = ((port->uartclk  * 100) / baud / quot) % 100;
377 		fraction = DIV_ROUND_CLOSEST(fraction, 10);
378 		serial_port_out(port, MTK_UART_FRACDIV_L,
379 						fraction_L_mapping[fraction]);
380 		serial_port_out(port, MTK_UART_FRACDIV_M,
381 						fraction_M_mapping[fraction]);
382 	} else {
383 		serial_port_out(port, MTK_UART_SAMPLE_COUNT, 0x00);
384 		serial_port_out(port, MTK_UART_SAMPLE_POINT, 0xff);
385 		serial_port_out(port, MTK_UART_FRACDIV_L, 0x00);
386 		serial_port_out(port, MTK_UART_FRACDIV_M, 0x00);
387 	}
388 
389 	if ((termios->c_cflag & CRTSCTS) && (!(termios->c_iflag & CRTSCTS)))
390 		mode = MTK_UART_FC_HW;
391 	else if (termios->c_iflag & CRTSCTS)
392 		mode = MTK_UART_FC_SW;
393 	else
394 		mode = MTK_UART_FC_NONE;
395 
396 	mtk8250_set_flow_ctrl(up, mode);
397 
398 	if (uart_console(port))
399 		up->port.cons->cflag = termios->c_cflag;
400 
401 	spin_unlock_irqrestore(&port->lock, flags);
402 	/* Don't rewrite B0 */
403 	if (tty_termios_baud_rate(termios))
404 		tty_termios_encode_baud_rate(termios, baud, baud);
405 }
406 
407 static int __maybe_unused mtk8250_runtime_suspend(struct device *dev)
408 {
409 	struct mtk8250_data *data = dev_get_drvdata(dev);
410 	struct uart_8250_port *up = serial8250_get_port(data->line);
411 
412 	/* wait until UART in idle status */
413 	while
414 		(serial_in(up, MTK_UART_DEBUG0));
415 
416 	if (data->clk_count == 0U) {
417 		dev_dbg(dev, "%s clock count is 0\n", __func__);
418 	} else {
419 		clk_disable_unprepare(data->bus_clk);
420 		data->clk_count--;
421 	}
422 
423 	return 0;
424 }
425 
426 static int __maybe_unused mtk8250_runtime_resume(struct device *dev)
427 {
428 	struct mtk8250_data *data = dev_get_drvdata(dev);
429 	int err;
430 
431 	if (data->clk_count > 0U) {
432 		dev_dbg(dev, "%s clock count is %d\n", __func__,
433 			data->clk_count);
434 	} else {
435 		err = clk_prepare_enable(data->bus_clk);
436 		if (err) {
437 			dev_warn(dev, "Can't enable bus clock\n");
438 			return err;
439 		}
440 		data->clk_count++;
441 	}
442 
443 	return 0;
444 }
445 
446 static void
447 mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
448 {
449 	if (!state)
450 		if (!mtk8250_runtime_resume(port->dev))
451 			pm_runtime_get_sync(port->dev);
452 
453 	serial8250_do_pm(port, state, old);
454 
455 	if (state)
456 		if (!pm_runtime_put_sync_suspend(port->dev))
457 			mtk8250_runtime_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(&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 	pm_runtime_enable(&pdev->dev);
573 	err = mtk8250_runtime_resume(&pdev->dev);
574 	if (err)
575 		goto err_pm_disable;
576 
577 	data->line = serial8250_register_8250_port(&uart);
578 	if (data->line < 0) {
579 		err = data->line;
580 		goto err_pm_disable;
581 	}
582 
583 	data->rx_wakeup_irq = platform_get_irq_optional(pdev, 1);
584 
585 	return 0;
586 
587 err_pm_disable:
588 	pm_runtime_disable(&pdev->dev);
589 
590 	return err;
591 }
592 
593 static int mtk8250_remove(struct platform_device *pdev)
594 {
595 	struct mtk8250_data *data = platform_get_drvdata(pdev);
596 
597 	pm_runtime_get_sync(&pdev->dev);
598 
599 	serial8250_unregister_port(data->line);
600 
601 	pm_runtime_disable(&pdev->dev);
602 	pm_runtime_put_noidle(&pdev->dev);
603 
604 	if (!pm_runtime_status_suspended(&pdev->dev))
605 		mtk8250_runtime_suspend(&pdev->dev);
606 
607 	return 0;
608 }
609 
610 static int __maybe_unused mtk8250_suspend(struct device *dev)
611 {
612 	struct mtk8250_data *data = dev_get_drvdata(dev);
613 	int irq = data->rx_wakeup_irq;
614 	int err;
615 
616 	serial8250_suspend_port(data->line);
617 
618 	pinctrl_pm_select_sleep_state(dev);
619 	if (irq >= 0) {
620 		err = enable_irq_wake(irq);
621 		if (err) {
622 			dev_err(dev,
623 				"failed to enable irq wake on IRQ %d: %d\n",
624 				irq, err);
625 			pinctrl_pm_select_default_state(dev);
626 			serial8250_resume_port(data->line);
627 			return err;
628 		}
629 	}
630 
631 	return 0;
632 }
633 
634 static int __maybe_unused mtk8250_resume(struct device *dev)
635 {
636 	struct mtk8250_data *data = dev_get_drvdata(dev);
637 	int irq = data->rx_wakeup_irq;
638 
639 	if (irq >= 0)
640 		disable_irq_wake(irq);
641 	pinctrl_pm_select_default_state(dev);
642 
643 	serial8250_resume_port(data->line);
644 
645 	return 0;
646 }
647 
648 static const struct dev_pm_ops mtk8250_pm_ops = {
649 	SET_SYSTEM_SLEEP_PM_OPS(mtk8250_suspend, mtk8250_resume)
650 	SET_RUNTIME_PM_OPS(mtk8250_runtime_suspend, mtk8250_runtime_resume,
651 				NULL)
652 };
653 
654 static const struct of_device_id mtk8250_of_match[] = {
655 	{ .compatible = "mediatek,mt6577-uart" },
656 	{ /* Sentinel */ }
657 };
658 MODULE_DEVICE_TABLE(of, mtk8250_of_match);
659 
660 static struct platform_driver mtk8250_platform_driver = {
661 	.driver = {
662 		.name		= "mt6577-uart",
663 		.pm		= &mtk8250_pm_ops,
664 		.of_match_table	= mtk8250_of_match,
665 	},
666 	.probe			= mtk8250_probe,
667 	.remove			= mtk8250_remove,
668 };
669 module_platform_driver(mtk8250_platform_driver);
670 
671 #ifdef CONFIG_SERIAL_8250_CONSOLE
672 static int __init early_mtk8250_setup(struct earlycon_device *device,
673 					const char *options)
674 {
675 	if (!device->port.membase)
676 		return -ENODEV;
677 
678 	device->port.iotype = UPIO_MEM32;
679 	device->port.regshift = 2;
680 
681 	return early_serial8250_setup(device, NULL);
682 }
683 
684 OF_EARLYCON_DECLARE(mtk8250, "mediatek,mt6577-uart", early_mtk8250_setup);
685 #endif
686 
687 MODULE_AUTHOR("Matthias Brugger");
688 MODULE_LICENSE("GPL");
689 MODULE_DESCRIPTION("Mediatek 8250 serial port driver");
690