xref: /openbmc/linux/drivers/usb/host/ohci-at91.c (revision 089a49b6)
1 /*
2  * OHCI HCD (Host Controller Driver) for USB.
3  *
4  *  Copyright (C) 2004 SAN People (Pty) Ltd.
5  *  Copyright (C) 2005 Thibaut VARENE <varenet@parisc-linux.org>
6  *
7  * AT91 Bus Glue
8  *
9  * Based on fragments of 2.4 driver by Rick Bronson.
10  * Based on ohci-omap.c
11  *
12  * This file is licenced under the GPL.
13  */
14 
15 #include <linux/clk.h>
16 #include <linux/platform_device.h>
17 #include <linux/of_platform.h>
18 #include <linux/of_gpio.h>
19 #include <linux/platform_data/atmel.h>
20 
21 #include <mach/hardware.h>
22 #include <asm/gpio.h>
23 
24 #include <mach/cpu.h>
25 
26 #ifndef CONFIG_ARCH_AT91
27 #error "CONFIG_ARCH_AT91 must be defined."
28 #endif
29 
30 #define valid_port(index)	((index) >= 0 && (index) < AT91_MAX_USBH_PORTS)
31 #define at91_for_each_port(index)	\
32 		for ((index) = 0; (index) < AT91_MAX_USBH_PORTS; (index)++)
33 
34 /* interface, function and usb clocks; sometimes also an AHB clock */
35 static struct clk *iclk, *fclk, *uclk, *hclk;
36 static int clocked;
37 
38 extern int usb_disabled(void);
39 
40 /*-------------------------------------------------------------------------*/
41 
42 static void at91_start_clock(void)
43 {
44 	if (IS_ENABLED(CONFIG_COMMON_CLK)) {
45 		clk_set_rate(uclk, 48000000);
46 		clk_prepare_enable(uclk);
47 	}
48 	clk_prepare_enable(hclk);
49 	clk_prepare_enable(iclk);
50 	clk_prepare_enable(fclk);
51 	clocked = 1;
52 }
53 
54 static void at91_stop_clock(void)
55 {
56 	clk_disable_unprepare(fclk);
57 	clk_disable_unprepare(iclk);
58 	clk_disable_unprepare(hclk);
59 	if (IS_ENABLED(CONFIG_COMMON_CLK))
60 		clk_disable_unprepare(uclk);
61 	clocked = 0;
62 }
63 
64 static void at91_start_hc(struct platform_device *pdev)
65 {
66 	struct usb_hcd *hcd = platform_get_drvdata(pdev);
67 	struct ohci_regs __iomem *regs = hcd->regs;
68 
69 	dev_dbg(&pdev->dev, "start\n");
70 
71 	/*
72 	 * Start the USB clocks.
73 	 */
74 	at91_start_clock();
75 
76 	/*
77 	 * The USB host controller must remain in reset.
78 	 */
79 	writel(0, &regs->control);
80 }
81 
82 static void at91_stop_hc(struct platform_device *pdev)
83 {
84 	struct usb_hcd *hcd = platform_get_drvdata(pdev);
85 	struct ohci_regs __iomem *regs = hcd->regs;
86 
87 	dev_dbg(&pdev->dev, "stop\n");
88 
89 	/*
90 	 * Put the USB host controller into reset.
91 	 */
92 	writel(0, &regs->control);
93 
94 	/*
95 	 * Stop the USB clocks.
96 	 */
97 	at91_stop_clock();
98 }
99 
100 
101 /*-------------------------------------------------------------------------*/
102 
103 static void usb_hcd_at91_remove (struct usb_hcd *, struct platform_device *);
104 
105 /* configure so an HC device and id are always provided */
106 /* always called with process context; sleeping is OK */
107 
108 
109 /**
110  * usb_hcd_at91_probe - initialize AT91-based HCDs
111  * Context: !in_interrupt()
112  *
113  * Allocates basic resources for this USB host controller, and
114  * then invokes the start() method for the HCD associated with it
115  * through the hotplug entry's driver_data.
116  */
117 static int usb_hcd_at91_probe(const struct hc_driver *driver,
118 			struct platform_device *pdev)
119 {
120 	int retval;
121 	struct usb_hcd *hcd = NULL;
122 
123 	if (pdev->num_resources != 2) {
124 		pr_debug("hcd probe: invalid num_resources");
125 		return -ENODEV;
126 	}
127 
128 	if ((pdev->resource[0].flags != IORESOURCE_MEM)
129 			|| (pdev->resource[1].flags != IORESOURCE_IRQ)) {
130 		pr_debug("hcd probe: invalid resource type\n");
131 		return -ENODEV;
132 	}
133 
134 	hcd = usb_create_hcd(driver, &pdev->dev, "at91");
135 	if (!hcd)
136 		return -ENOMEM;
137 	hcd->rsrc_start = pdev->resource[0].start;
138 	hcd->rsrc_len = resource_size(&pdev->resource[0]);
139 
140 	if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len, hcd_name)) {
141 		pr_debug("request_mem_region failed\n");
142 		retval = -EBUSY;
143 		goto err1;
144 	}
145 
146 	hcd->regs = ioremap(hcd->rsrc_start, hcd->rsrc_len);
147 	if (!hcd->regs) {
148 		pr_debug("ioremap failed\n");
149 		retval = -EIO;
150 		goto err2;
151 	}
152 
153 	iclk = clk_get(&pdev->dev, "ohci_clk");
154 	if (IS_ERR(iclk)) {
155 		dev_err(&pdev->dev, "failed to get ohci_clk\n");
156 		retval = PTR_ERR(iclk);
157 		goto err3;
158 	}
159 	fclk = clk_get(&pdev->dev, "uhpck");
160 	if (IS_ERR(fclk)) {
161 		dev_err(&pdev->dev, "failed to get uhpck\n");
162 		retval = PTR_ERR(fclk);
163 		goto err4;
164 	}
165 	hclk = clk_get(&pdev->dev, "hclk");
166 	if (IS_ERR(hclk)) {
167 		dev_err(&pdev->dev, "failed to get hclk\n");
168 		retval = PTR_ERR(hclk);
169 		goto err5;
170 	}
171 	if (IS_ENABLED(CONFIG_COMMON_CLK)) {
172 		uclk = clk_get(&pdev->dev, "usb_clk");
173 		if (IS_ERR(uclk)) {
174 			dev_err(&pdev->dev, "failed to get uclk\n");
175 			retval = PTR_ERR(uclk);
176 			goto err6;
177 		}
178 	}
179 
180 	at91_start_hc(pdev);
181 	ohci_hcd_init(hcd_to_ohci(hcd));
182 
183 	retval = usb_add_hcd(hcd, pdev->resource[1].start, IRQF_SHARED);
184 	if (retval == 0)
185 		return retval;
186 
187 	/* Error handling */
188 	at91_stop_hc(pdev);
189 
190 	if (IS_ENABLED(CONFIG_COMMON_CLK))
191 		clk_put(uclk);
192  err6:
193 	clk_put(hclk);
194  err5:
195 	clk_put(fclk);
196  err4:
197 	clk_put(iclk);
198 
199  err3:
200 	iounmap(hcd->regs);
201 
202  err2:
203 	release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
204 
205  err1:
206 	usb_put_hcd(hcd);
207 	return retval;
208 }
209 
210 
211 /* may be called with controller, bus, and devices active */
212 
213 /**
214  * usb_hcd_at91_remove - shutdown processing for AT91-based HCDs
215  * @dev: USB Host Controller being removed
216  * Context: !in_interrupt()
217  *
218  * Reverses the effect of usb_hcd_at91_probe(), first invoking
219  * the HCD's stop() method.  It is always called from a thread
220  * context, "rmmod" or something similar.
221  *
222  */
223 static void usb_hcd_at91_remove(struct usb_hcd *hcd,
224 				struct platform_device *pdev)
225 {
226 	usb_remove_hcd(hcd);
227 	at91_stop_hc(pdev);
228 	iounmap(hcd->regs);
229 	release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
230 	usb_put_hcd(hcd);
231 
232 	if (IS_ENABLED(CONFIG_COMMON_CLK))
233 		clk_put(uclk);
234 	clk_put(hclk);
235 	clk_put(fclk);
236 	clk_put(iclk);
237 	fclk = iclk = hclk = NULL;
238 }
239 
240 /*-------------------------------------------------------------------------*/
241 
242 static int
243 ohci_at91_reset (struct usb_hcd *hcd)
244 {
245 	struct at91_usbh_data	*board = dev_get_platdata(hcd->self.controller);
246 	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
247 	int			ret;
248 
249 	if ((ret = ohci_init(ohci)) < 0)
250 		return ret;
251 
252 	ohci->num_ports = board->ports;
253 	return 0;
254 }
255 
256 static int
257 ohci_at91_start (struct usb_hcd *hcd)
258 {
259 	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
260 	int			ret;
261 
262 	if ((ret = ohci_run(ohci)) < 0) {
263 		dev_err(hcd->self.controller, "can't start %s\n",
264 			hcd->self.bus_name);
265 		ohci_stop(hcd);
266 		return ret;
267 	}
268 	return 0;
269 }
270 
271 static void ohci_at91_usb_set_power(struct at91_usbh_data *pdata, int port, int enable)
272 {
273 	if (!valid_port(port))
274 		return;
275 
276 	if (!gpio_is_valid(pdata->vbus_pin[port]))
277 		return;
278 
279 	gpio_set_value(pdata->vbus_pin[port],
280 		       pdata->vbus_pin_active_low[port] ^ enable);
281 }
282 
283 static int ohci_at91_usb_get_power(struct at91_usbh_data *pdata, int port)
284 {
285 	if (!valid_port(port))
286 		return -EINVAL;
287 
288 	if (!gpio_is_valid(pdata->vbus_pin[port]))
289 		return -EINVAL;
290 
291 	return gpio_get_value(pdata->vbus_pin[port]) ^
292 		pdata->vbus_pin_active_low[port];
293 }
294 
295 /*
296  * Update the status data from the hub with the over-current indicator change.
297  */
298 static int ohci_at91_hub_status_data(struct usb_hcd *hcd, char *buf)
299 {
300 	struct at91_usbh_data *pdata = dev_get_platdata(hcd->self.controller);
301 	int length = ohci_hub_status_data(hcd, buf);
302 	int port;
303 
304 	at91_for_each_port(port) {
305 		if (pdata->overcurrent_changed[port]) {
306 			if (!length)
307 				length = 1;
308 			buf[0] |= 1 << (port + 1);
309 		}
310 	}
311 
312 	return length;
313 }
314 
315 /*
316  * Look at the control requests to the root hub and see if we need to override.
317  */
318 static int ohci_at91_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
319 				 u16 wIndex, char *buf, u16 wLength)
320 {
321 	struct at91_usbh_data *pdata = dev_get_platdata(hcd->self.controller);
322 	struct usb_hub_descriptor *desc;
323 	int ret = -EINVAL;
324 	u32 *data = (u32 *)buf;
325 
326 	dev_dbg(hcd->self.controller,
327 		"ohci_at91_hub_control(%p,0x%04x,0x%04x,0x%04x,%p,%04x)\n",
328 		hcd, typeReq, wValue, wIndex, buf, wLength);
329 
330 	wIndex--;
331 
332 	switch (typeReq) {
333 	case SetPortFeature:
334 		if (wValue == USB_PORT_FEAT_POWER) {
335 			dev_dbg(hcd->self.controller, "SetPortFeat: POWER\n");
336 			if (valid_port(wIndex)) {
337 				ohci_at91_usb_set_power(pdata, wIndex, 1);
338 				ret = 0;
339 			}
340 
341 			goto out;
342 		}
343 		break;
344 
345 	case ClearPortFeature:
346 		switch (wValue) {
347 		case USB_PORT_FEAT_C_OVER_CURRENT:
348 			dev_dbg(hcd->self.controller,
349 				"ClearPortFeature: C_OVER_CURRENT\n");
350 
351 			if (valid_port(wIndex)) {
352 				pdata->overcurrent_changed[wIndex] = 0;
353 				pdata->overcurrent_status[wIndex] = 0;
354 			}
355 
356 			goto out;
357 
358 		case USB_PORT_FEAT_OVER_CURRENT:
359 			dev_dbg(hcd->self.controller,
360 				"ClearPortFeature: OVER_CURRENT\n");
361 
362 			if (valid_port(wIndex))
363 				pdata->overcurrent_status[wIndex] = 0;
364 
365 			goto out;
366 
367 		case USB_PORT_FEAT_POWER:
368 			dev_dbg(hcd->self.controller,
369 				"ClearPortFeature: POWER\n");
370 
371 			if (valid_port(wIndex)) {
372 				ohci_at91_usb_set_power(pdata, wIndex, 0);
373 				return 0;
374 			}
375 		}
376 		break;
377 	}
378 
379 	ret = ohci_hub_control(hcd, typeReq, wValue, wIndex + 1, buf, wLength);
380 	if (ret)
381 		goto out;
382 
383 	switch (typeReq) {
384 	case GetHubDescriptor:
385 
386 		/* update the hub's descriptor */
387 
388 		desc = (struct usb_hub_descriptor *)buf;
389 
390 		dev_dbg(hcd->self.controller, "wHubCharacteristics 0x%04x\n",
391 			desc->wHubCharacteristics);
392 
393 		/* remove the old configurations for power-switching, and
394 		 * over-current protection, and insert our new configuration
395 		 */
396 
397 		desc->wHubCharacteristics &= ~cpu_to_le16(HUB_CHAR_LPSM);
398 		desc->wHubCharacteristics |= cpu_to_le16(0x0001);
399 
400 		if (pdata->overcurrent_supported) {
401 			desc->wHubCharacteristics &= ~cpu_to_le16(HUB_CHAR_OCPM);
402 			desc->wHubCharacteristics |=  cpu_to_le16(0x0008|0x0001);
403 		}
404 
405 		dev_dbg(hcd->self.controller, "wHubCharacteristics after 0x%04x\n",
406 			desc->wHubCharacteristics);
407 
408 		return ret;
409 
410 	case GetPortStatus:
411 		/* check port status */
412 
413 		dev_dbg(hcd->self.controller, "GetPortStatus(%d)\n", wIndex);
414 
415 		if (valid_port(wIndex)) {
416 			if (!ohci_at91_usb_get_power(pdata, wIndex))
417 				*data &= ~cpu_to_le32(RH_PS_PPS);
418 
419 			if (pdata->overcurrent_changed[wIndex])
420 				*data |= cpu_to_le32(RH_PS_OCIC);
421 
422 			if (pdata->overcurrent_status[wIndex])
423 				*data |= cpu_to_le32(RH_PS_POCI);
424 		}
425 	}
426 
427  out:
428 	return ret;
429 }
430 
431 /*-------------------------------------------------------------------------*/
432 
433 static const struct hc_driver ohci_at91_hc_driver = {
434 	.description =		hcd_name,
435 	.product_desc =		"AT91 OHCI",
436 	.hcd_priv_size =	sizeof(struct ohci_hcd),
437 
438 	/*
439 	 * generic hardware linkage
440 	 */
441 	.irq =			ohci_irq,
442 	.flags =		HCD_USB11 | HCD_MEMORY,
443 
444 	/*
445 	 * basic lifecycle operations
446 	 */
447 	.reset =		ohci_at91_reset,
448 	.start =		ohci_at91_start,
449 	.stop =			ohci_stop,
450 	.shutdown =		ohci_shutdown,
451 
452 	/*
453 	 * managing i/o requests and associated device resources
454 	 */
455 	.urb_enqueue =		ohci_urb_enqueue,
456 	.urb_dequeue =		ohci_urb_dequeue,
457 	.endpoint_disable =	ohci_endpoint_disable,
458 
459 	/*
460 	 * scheduling support
461 	 */
462 	.get_frame_number =	ohci_get_frame,
463 
464 	/*
465 	 * root hub support
466 	 */
467 	.hub_status_data =	ohci_at91_hub_status_data,
468 	.hub_control =		ohci_at91_hub_control,
469 #ifdef CONFIG_PM
470 	.bus_suspend =		ohci_bus_suspend,
471 	.bus_resume =		ohci_bus_resume,
472 #endif
473 	.start_port_reset =	ohci_start_port_reset,
474 };
475 
476 /*-------------------------------------------------------------------------*/
477 
478 static irqreturn_t ohci_hcd_at91_overcurrent_irq(int irq, void *data)
479 {
480 	struct platform_device *pdev = data;
481 	struct at91_usbh_data *pdata = dev_get_platdata(&pdev->dev);
482 	int val, gpio, port;
483 
484 	/* From the GPIO notifying the over-current situation, find
485 	 * out the corresponding port */
486 	at91_for_each_port(port) {
487 		if (gpio_is_valid(pdata->overcurrent_pin[port]) &&
488 				gpio_to_irq(pdata->overcurrent_pin[port]) == irq) {
489 			gpio = pdata->overcurrent_pin[port];
490 			break;
491 		}
492 	}
493 
494 	if (port == AT91_MAX_USBH_PORTS) {
495 		dev_err(& pdev->dev, "overcurrent interrupt from unknown GPIO\n");
496 		return IRQ_HANDLED;
497 	}
498 
499 	val = gpio_get_value(gpio);
500 
501 	/* When notified of an over-current situation, disable power
502 	   on the corresponding port, and mark this port in
503 	   over-current. */
504 	if (!val) {
505 		ohci_at91_usb_set_power(pdata, port, 0);
506 		pdata->overcurrent_status[port]  = 1;
507 		pdata->overcurrent_changed[port] = 1;
508 	}
509 
510 	dev_dbg(& pdev->dev, "overcurrent situation %s\n",
511 		val ? "exited" : "notified");
512 
513 	return IRQ_HANDLED;
514 }
515 
516 #ifdef CONFIG_OF
517 static const struct of_device_id at91_ohci_dt_ids[] = {
518 	{ .compatible = "atmel,at91rm9200-ohci" },
519 	{ /* sentinel */ }
520 };
521 
522 MODULE_DEVICE_TABLE(of, at91_ohci_dt_ids);
523 
524 static int ohci_at91_of_init(struct platform_device *pdev)
525 {
526 	struct device_node *np = pdev->dev.of_node;
527 	int i, gpio;
528 	enum of_gpio_flags flags;
529 	struct at91_usbh_data	*pdata;
530 	u32 ports;
531 
532 	if (!np)
533 		return 0;
534 
535 	/* Right now device-tree probed devices don't get dma_mask set.
536 	 * Since shared usb code relies on it, set it here for now.
537 	 * Once we have dma capability bindings this can go away.
538 	 */
539 	if (!pdev->dev.dma_mask)
540 		pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
541 	if (!pdev->dev.coherent_dma_mask)
542 		pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
543 
544 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
545 	if (!pdata)
546 		return -ENOMEM;
547 
548 	if (!of_property_read_u32(np, "num-ports", &ports))
549 		pdata->ports = ports;
550 
551 	at91_for_each_port(i) {
552 		gpio = of_get_named_gpio_flags(np, "atmel,vbus-gpio", i, &flags);
553 		pdata->vbus_pin[i] = gpio;
554 		if (!gpio_is_valid(gpio))
555 			continue;
556 		pdata->vbus_pin_active_low[i] = flags & OF_GPIO_ACTIVE_LOW;
557 	}
558 
559 	at91_for_each_port(i)
560 		pdata->overcurrent_pin[i] =
561 			of_get_named_gpio_flags(np, "atmel,oc-gpio", i, &flags);
562 
563 	pdev->dev.platform_data = pdata;
564 
565 	return 0;
566 }
567 #else
568 static int ohci_at91_of_init(struct platform_device *pdev)
569 {
570 	return 0;
571 }
572 #endif
573 
574 /*-------------------------------------------------------------------------*/
575 
576 static int ohci_hcd_at91_drv_probe(struct platform_device *pdev)
577 {
578 	struct at91_usbh_data	*pdata;
579 	int			i;
580 	int			gpio;
581 	int			ret;
582 
583 	ret = ohci_at91_of_init(pdev);
584 	if (ret)
585 		return ret;
586 
587 	pdata = dev_get_platdata(&pdev->dev);
588 
589 	if (pdata) {
590 		at91_for_each_port(i) {
591 			/*
592 			 * do not configure PIO if not in relation with
593 			 * real USB port on board
594 			 */
595 			if (i >= pdata->ports) {
596 				pdata->vbus_pin[i] = -EINVAL;
597 				pdata->overcurrent_pin[i] = -EINVAL;
598 				break;
599 			}
600 
601 			if (!gpio_is_valid(pdata->vbus_pin[i]))
602 				continue;
603 			gpio = pdata->vbus_pin[i];
604 
605 			ret = gpio_request(gpio, "ohci_vbus");
606 			if (ret) {
607 				dev_err(&pdev->dev,
608 					"can't request vbus gpio %d\n", gpio);
609 				continue;
610 			}
611 			ret = gpio_direction_output(gpio,
612 						!pdata->vbus_pin_active_low[i]);
613 			if (ret) {
614 				dev_err(&pdev->dev,
615 					"can't put vbus gpio %d as output %d\n",
616 					gpio, !pdata->vbus_pin_active_low[i]);
617 				gpio_free(gpio);
618 				continue;
619 			}
620 
621 			ohci_at91_usb_set_power(pdata, i, 1);
622 		}
623 
624 		at91_for_each_port(i) {
625 			if (!gpio_is_valid(pdata->overcurrent_pin[i]))
626 				continue;
627 			gpio = pdata->overcurrent_pin[i];
628 
629 			ret = gpio_request(gpio, "ohci_overcurrent");
630 			if (ret) {
631 				dev_err(&pdev->dev,
632 					"can't request overcurrent gpio %d\n",
633 					gpio);
634 				continue;
635 			}
636 
637 			ret = gpio_direction_input(gpio);
638 			if (ret) {
639 				dev_err(&pdev->dev,
640 					"can't configure overcurrent gpio %d as input\n",
641 					gpio);
642 				gpio_free(gpio);
643 				continue;
644 			}
645 
646 			ret = request_irq(gpio_to_irq(gpio),
647 					  ohci_hcd_at91_overcurrent_irq,
648 					  IRQF_SHARED, "ohci_overcurrent", pdev);
649 			if (ret) {
650 				gpio_free(gpio);
651 				dev_err(&pdev->dev,
652 					"can't get gpio IRQ for overcurrent\n");
653 			}
654 		}
655 	}
656 
657 	device_init_wakeup(&pdev->dev, 1);
658 	return usb_hcd_at91_probe(&ohci_at91_hc_driver, pdev);
659 }
660 
661 static int ohci_hcd_at91_drv_remove(struct platform_device *pdev)
662 {
663 	struct at91_usbh_data	*pdata = dev_get_platdata(&pdev->dev);
664 	int			i;
665 
666 	if (pdata) {
667 		at91_for_each_port(i) {
668 			if (!gpio_is_valid(pdata->vbus_pin[i]))
669 				continue;
670 			ohci_at91_usb_set_power(pdata, i, 0);
671 			gpio_free(pdata->vbus_pin[i]);
672 		}
673 
674 		at91_for_each_port(i) {
675 			if (!gpio_is_valid(pdata->overcurrent_pin[i]))
676 				continue;
677 			free_irq(gpio_to_irq(pdata->overcurrent_pin[i]), pdev);
678 			gpio_free(pdata->overcurrent_pin[i]);
679 		}
680 	}
681 
682 	device_init_wakeup(&pdev->dev, 0);
683 	usb_hcd_at91_remove(platform_get_drvdata(pdev), pdev);
684 	return 0;
685 }
686 
687 #ifdef CONFIG_PM
688 
689 static int
690 ohci_hcd_at91_drv_suspend(struct platform_device *pdev, pm_message_t mesg)
691 {
692 	struct usb_hcd	*hcd = platform_get_drvdata(pdev);
693 	struct ohci_hcd	*ohci = hcd_to_ohci(hcd);
694 
695 	if (device_may_wakeup(&pdev->dev))
696 		enable_irq_wake(hcd->irq);
697 
698 	/*
699 	 * The integrated transceivers seem unable to notice disconnect,
700 	 * reconnect, or wakeup without the 48 MHz clock active.  so for
701 	 * correctness, always discard connection state (using reset).
702 	 *
703 	 * REVISIT: some boards will be able to turn VBUS off...
704 	 */
705 	if (at91_suspend_entering_slow_clock()) {
706 		ohci_usb_reset (ohci);
707 		/* flush the writes */
708 		(void) ohci_readl (ohci, &ohci->regs->control);
709 		at91_stop_clock();
710 	}
711 
712 	return 0;
713 }
714 
715 static int ohci_hcd_at91_drv_resume(struct platform_device *pdev)
716 {
717 	struct usb_hcd	*hcd = platform_get_drvdata(pdev);
718 
719 	if (device_may_wakeup(&pdev->dev))
720 		disable_irq_wake(hcd->irq);
721 
722 	if (!clocked)
723 		at91_start_clock();
724 
725 	ohci_resume(hcd, false);
726 	return 0;
727 }
728 #else
729 #define ohci_hcd_at91_drv_suspend NULL
730 #define ohci_hcd_at91_drv_resume  NULL
731 #endif
732 
733 MODULE_ALIAS("platform:at91_ohci");
734 
735 static struct platform_driver ohci_hcd_at91_driver = {
736 	.probe		= ohci_hcd_at91_drv_probe,
737 	.remove		= ohci_hcd_at91_drv_remove,
738 	.shutdown	= usb_hcd_platform_shutdown,
739 	.suspend	= ohci_hcd_at91_drv_suspend,
740 	.resume		= ohci_hcd_at91_drv_resume,
741 	.driver		= {
742 		.name	= "at91_ohci",
743 		.owner	= THIS_MODULE,
744 		.of_match_table	= of_match_ptr(at91_ohci_dt_ids),
745 	},
746 };
747