xref: /openbmc/linux/drivers/usb/phy/phy-mv-usb.c (revision a2818ee4) 
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2011 Marvell International Ltd. All rights reserved.
4  * Author: Chao Xie <chao.xie@marvell.com>
5  *	   Neil Zhang <zhangwm@marvell.com>
6  */
7 
8 #include <linux/module.h>
9 #include <linux/kernel.h>
10 #include <linux/io.h>
11 #include <linux/uaccess.h>
12 #include <linux/device.h>
13 #include <linux/proc_fs.h>
14 #include <linux/clk.h>
15 #include <linux/workqueue.h>
16 #include <linux/platform_device.h>
17 
18 #include <linux/usb.h>
19 #include <linux/usb/ch9.h>
20 #include <linux/usb/otg.h>
21 #include <linux/usb/gadget.h>
22 #include <linux/usb/hcd.h>
23 #include <linux/platform_data/mv_usb.h>
24 
25 #include "phy-mv-usb.h"
26 
27 #define	DRIVER_DESC	"Marvell USB OTG transceiver driver"
28 
29 MODULE_DESCRIPTION(DRIVER_DESC);
30 MODULE_LICENSE("GPL");
31 
32 static const char driver_name[] = "mv-otg";
33 
34 static char *state_string[] = {
35 	"undefined",
36 	"b_idle",
37 	"b_srp_init",
38 	"b_peripheral",
39 	"b_wait_acon",
40 	"b_host",
41 	"a_idle",
42 	"a_wait_vrise",
43 	"a_wait_bcon",
44 	"a_host",
45 	"a_suspend",
46 	"a_peripheral",
47 	"a_wait_vfall",
48 	"a_vbus_err"
49 };
50 
51 static int mv_otg_set_vbus(struct usb_otg *otg, bool on)
52 {
53 	struct mv_otg *mvotg = container_of(otg->usb_phy, struct mv_otg, phy);
54 	if (mvotg->pdata->set_vbus == NULL)
55 		return -ENODEV;
56 
57 	return mvotg->pdata->set_vbus(on);
58 }
59 
60 static int mv_otg_set_host(struct usb_otg *otg,
61 			   struct usb_bus *host)
62 {
63 	otg->host = host;
64 
65 	return 0;
66 }
67 
68 static int mv_otg_set_peripheral(struct usb_otg *otg,
69 				 struct usb_gadget *gadget)
70 {
71 	otg->gadget = gadget;
72 
73 	return 0;
74 }
75 
76 static void mv_otg_run_state_machine(struct mv_otg *mvotg,
77 				     unsigned long delay)
78 {
79 	dev_dbg(&mvotg->pdev->dev, "transceiver is updated\n");
80 	if (!mvotg->qwork)
81 		return;
82 
83 	queue_delayed_work(mvotg->qwork, &mvotg->work, delay);
84 }
85 
86 static void mv_otg_timer_await_bcon(struct timer_list *t)
87 {
88 	struct mv_otg *mvotg = from_timer(mvotg, t,
89 					  otg_ctrl.timer[A_WAIT_BCON_TIMER]);
90 
91 	mvotg->otg_ctrl.a_wait_bcon_timeout = 1;
92 
93 	dev_info(&mvotg->pdev->dev, "B Device No Response!\n");
94 
95 	if (spin_trylock(&mvotg->wq_lock)) {
96 		mv_otg_run_state_machine(mvotg, 0);
97 		spin_unlock(&mvotg->wq_lock);
98 	}
99 }
100 
101 static int mv_otg_cancel_timer(struct mv_otg *mvotg, unsigned int id)
102 {
103 	struct timer_list *timer;
104 
105 	if (id >= OTG_TIMER_NUM)
106 		return -EINVAL;
107 
108 	timer = &mvotg->otg_ctrl.timer[id];
109 
110 	if (timer_pending(timer))
111 		del_timer(timer);
112 
113 	return 0;
114 }
115 
116 static int mv_otg_set_timer(struct mv_otg *mvotg, unsigned int id,
117 			    unsigned long interval)
118 {
119 	struct timer_list *timer;
120 
121 	if (id >= OTG_TIMER_NUM)
122 		return -EINVAL;
123 
124 	timer = &mvotg->otg_ctrl.timer[id];
125 	if (timer_pending(timer)) {
126 		dev_err(&mvotg->pdev->dev, "Timer%d is already running\n", id);
127 		return -EBUSY;
128 	}
129 
130 	timer->expires = jiffies + interval;
131 	add_timer(timer);
132 
133 	return 0;
134 }
135 
136 static int mv_otg_reset(struct mv_otg *mvotg)
137 {
138 	unsigned int loops;
139 	u32 tmp;
140 
141 	/* Stop the controller */
142 	tmp = readl(&mvotg->op_regs->usbcmd);
143 	tmp &= ~USBCMD_RUN_STOP;
144 	writel(tmp, &mvotg->op_regs->usbcmd);
145 
146 	/* Reset the controller to get default values */
147 	writel(USBCMD_CTRL_RESET, &mvotg->op_regs->usbcmd);
148 
149 	loops = 500;
150 	while (readl(&mvotg->op_regs->usbcmd) & USBCMD_CTRL_RESET) {
151 		if (loops == 0) {
152 			dev_err(&mvotg->pdev->dev,
153 				"Wait for RESET completed TIMEOUT\n");
154 			return -ETIMEDOUT;
155 		}
156 		loops--;
157 		udelay(20);
158 	}
159 
160 	writel(0x0, &mvotg->op_regs->usbintr);
161 	tmp = readl(&mvotg->op_regs->usbsts);
162 	writel(tmp, &mvotg->op_regs->usbsts);
163 
164 	return 0;
165 }
166 
167 static void mv_otg_init_irq(struct mv_otg *mvotg)
168 {
169 	u32 otgsc;
170 
171 	mvotg->irq_en = OTGSC_INTR_A_SESSION_VALID
172 	    | OTGSC_INTR_A_VBUS_VALID;
173 	mvotg->irq_status = OTGSC_INTSTS_A_SESSION_VALID
174 	    | OTGSC_INTSTS_A_VBUS_VALID;
175 
176 	if (mvotg->pdata->vbus == NULL) {
177 		mvotg->irq_en |= OTGSC_INTR_B_SESSION_VALID
178 		    | OTGSC_INTR_B_SESSION_END;
179 		mvotg->irq_status |= OTGSC_INTSTS_B_SESSION_VALID
180 		    | OTGSC_INTSTS_B_SESSION_END;
181 	}
182 
183 	if (mvotg->pdata->id == NULL) {
184 		mvotg->irq_en |= OTGSC_INTR_USB_ID;
185 		mvotg->irq_status |= OTGSC_INTSTS_USB_ID;
186 	}
187 
188 	otgsc = readl(&mvotg->op_regs->otgsc);
189 	otgsc |= mvotg->irq_en;
190 	writel(otgsc, &mvotg->op_regs->otgsc);
191 }
192 
193 static void mv_otg_start_host(struct mv_otg *mvotg, int on)
194 {
195 #ifdef CONFIG_USB
196 	struct usb_otg *otg = mvotg->phy.otg;
197 	struct usb_hcd *hcd;
198 
199 	if (!otg->host)
200 		return;
201 
202 	dev_info(&mvotg->pdev->dev, "%s host\n", on ? "start" : "stop");
203 
204 	hcd = bus_to_hcd(otg->host);
205 
206 	if (on) {
207 		usb_add_hcd(hcd, hcd->irq, IRQF_SHARED);
208 		device_wakeup_enable(hcd->self.controller);
209 	} else {
210 		usb_remove_hcd(hcd);
211 	}
212 #endif /* CONFIG_USB */
213 }
214 
215 static void mv_otg_start_periphrals(struct mv_otg *mvotg, int on)
216 {
217 	struct usb_otg *otg = mvotg->phy.otg;
218 
219 	if (!otg->gadget)
220 		return;
221 
222 	dev_info(mvotg->phy.dev, "gadget %s\n", on ? "on" : "off");
223 
224 	if (on)
225 		usb_gadget_vbus_connect(otg->gadget);
226 	else
227 		usb_gadget_vbus_disconnect(otg->gadget);
228 }
229 
230 static void otg_clock_enable(struct mv_otg *mvotg)
231 {
232 	clk_prepare_enable(mvotg->clk);
233 }
234 
235 static void otg_clock_disable(struct mv_otg *mvotg)
236 {
237 	clk_disable_unprepare(mvotg->clk);
238 }
239 
240 static int mv_otg_enable_internal(struct mv_otg *mvotg)
241 {
242 	int retval = 0;
243 
244 	if (mvotg->active)
245 		return 0;
246 
247 	dev_dbg(&mvotg->pdev->dev, "otg enabled\n");
248 
249 	otg_clock_enable(mvotg);
250 	if (mvotg->pdata->phy_init) {
251 		retval = mvotg->pdata->phy_init(mvotg->phy_regs);
252 		if (retval) {
253 			dev_err(&mvotg->pdev->dev,
254 				"init phy error %d\n", retval);
255 			otg_clock_disable(mvotg);
256 			return retval;
257 		}
258 	}
259 	mvotg->active = 1;
260 
261 	return 0;
262 
263 }
264 
265 static int mv_otg_enable(struct mv_otg *mvotg)
266 {
267 	if (mvotg->clock_gating)
268 		return mv_otg_enable_internal(mvotg);
269 
270 	return 0;
271 }
272 
273 static void mv_otg_disable_internal(struct mv_otg *mvotg)
274 {
275 	if (mvotg->active) {
276 		dev_dbg(&mvotg->pdev->dev, "otg disabled\n");
277 		if (mvotg->pdata->phy_deinit)
278 			mvotg->pdata->phy_deinit(mvotg->phy_regs);
279 		otg_clock_disable(mvotg);
280 		mvotg->active = 0;
281 	}
282 }
283 
284 static void mv_otg_disable(struct mv_otg *mvotg)
285 {
286 	if (mvotg->clock_gating)
287 		mv_otg_disable_internal(mvotg);
288 }
289 
290 static void mv_otg_update_inputs(struct mv_otg *mvotg)
291 {
292 	struct mv_otg_ctrl *otg_ctrl = &mvotg->otg_ctrl;
293 	u32 otgsc;
294 
295 	otgsc = readl(&mvotg->op_regs->otgsc);
296 
297 	if (mvotg->pdata->vbus) {
298 		if (mvotg->pdata->vbus->poll() == VBUS_HIGH) {
299 			otg_ctrl->b_sess_vld = 1;
300 			otg_ctrl->b_sess_end = 0;
301 		} else {
302 			otg_ctrl->b_sess_vld = 0;
303 			otg_ctrl->b_sess_end = 1;
304 		}
305 	} else {
306 		otg_ctrl->b_sess_vld = !!(otgsc & OTGSC_STS_B_SESSION_VALID);
307 		otg_ctrl->b_sess_end = !!(otgsc & OTGSC_STS_B_SESSION_END);
308 	}
309 
310 	if (mvotg->pdata->id)
311 		otg_ctrl->id = !!mvotg->pdata->id->poll();
312 	else
313 		otg_ctrl->id = !!(otgsc & OTGSC_STS_USB_ID);
314 
315 	if (mvotg->pdata->otg_force_a_bus_req && !otg_ctrl->id)
316 		otg_ctrl->a_bus_req = 1;
317 
318 	otg_ctrl->a_sess_vld = !!(otgsc & OTGSC_STS_A_SESSION_VALID);
319 	otg_ctrl->a_vbus_vld = !!(otgsc & OTGSC_STS_A_VBUS_VALID);
320 
321 	dev_dbg(&mvotg->pdev->dev, "%s: ", __func__);
322 	dev_dbg(&mvotg->pdev->dev, "id %d\n", otg_ctrl->id);
323 	dev_dbg(&mvotg->pdev->dev, "b_sess_vld %d\n", otg_ctrl->b_sess_vld);
324 	dev_dbg(&mvotg->pdev->dev, "b_sess_end %d\n", otg_ctrl->b_sess_end);
325 	dev_dbg(&mvotg->pdev->dev, "a_vbus_vld %d\n", otg_ctrl->a_vbus_vld);
326 	dev_dbg(&mvotg->pdev->dev, "a_sess_vld %d\n", otg_ctrl->a_sess_vld);
327 }
328 
329 static void mv_otg_update_state(struct mv_otg *mvotg)
330 {
331 	struct mv_otg_ctrl *otg_ctrl = &mvotg->otg_ctrl;
332 	int old_state = mvotg->phy.otg->state;
333 
334 	switch (old_state) {
335 	case OTG_STATE_UNDEFINED:
336 		mvotg->phy.otg->state = OTG_STATE_B_IDLE;
337 		/* FALL THROUGH */
338 	case OTG_STATE_B_IDLE:
339 		if (otg_ctrl->id == 0)
340 			mvotg->phy.otg->state = OTG_STATE_A_IDLE;
341 		else if (otg_ctrl->b_sess_vld)
342 			mvotg->phy.otg->state = OTG_STATE_B_PERIPHERAL;
343 		break;
344 	case OTG_STATE_B_PERIPHERAL:
345 		if (!otg_ctrl->b_sess_vld || otg_ctrl->id == 0)
346 			mvotg->phy.otg->state = OTG_STATE_B_IDLE;
347 		break;
348 	case OTG_STATE_A_IDLE:
349 		if (otg_ctrl->id)
350 			mvotg->phy.otg->state = OTG_STATE_B_IDLE;
351 		else if (!(otg_ctrl->a_bus_drop) &&
352 			 (otg_ctrl->a_bus_req || otg_ctrl->a_srp_det))
353 			mvotg->phy.otg->state = OTG_STATE_A_WAIT_VRISE;
354 		break;
355 	case OTG_STATE_A_WAIT_VRISE:
356 		if (otg_ctrl->a_vbus_vld)
357 			mvotg->phy.otg->state = OTG_STATE_A_WAIT_BCON;
358 		break;
359 	case OTG_STATE_A_WAIT_BCON:
360 		if (otg_ctrl->id || otg_ctrl->a_bus_drop
361 		    || otg_ctrl->a_wait_bcon_timeout) {
362 			mv_otg_cancel_timer(mvotg, A_WAIT_BCON_TIMER);
363 			mvotg->otg_ctrl.a_wait_bcon_timeout = 0;
364 			mvotg->phy.otg->state = OTG_STATE_A_WAIT_VFALL;
365 			otg_ctrl->a_bus_req = 0;
366 		} else if (!otg_ctrl->a_vbus_vld) {
367 			mv_otg_cancel_timer(mvotg, A_WAIT_BCON_TIMER);
368 			mvotg->otg_ctrl.a_wait_bcon_timeout = 0;
369 			mvotg->phy.otg->state = OTG_STATE_A_VBUS_ERR;
370 		} else if (otg_ctrl->b_conn) {
371 			mv_otg_cancel_timer(mvotg, A_WAIT_BCON_TIMER);
372 			mvotg->otg_ctrl.a_wait_bcon_timeout = 0;
373 			mvotg->phy.otg->state = OTG_STATE_A_HOST;
374 		}
375 		break;
376 	case OTG_STATE_A_HOST:
377 		if (otg_ctrl->id || !otg_ctrl->b_conn
378 		    || otg_ctrl->a_bus_drop)
379 			mvotg->phy.otg->state = OTG_STATE_A_WAIT_BCON;
380 		else if (!otg_ctrl->a_vbus_vld)
381 			mvotg->phy.otg->state = OTG_STATE_A_VBUS_ERR;
382 		break;
383 	case OTG_STATE_A_WAIT_VFALL:
384 		if (otg_ctrl->id
385 		    || (!otg_ctrl->b_conn && otg_ctrl->a_sess_vld)
386 		    || otg_ctrl->a_bus_req)
387 			mvotg->phy.otg->state = OTG_STATE_A_IDLE;
388 		break;
389 	case OTG_STATE_A_VBUS_ERR:
390 		if (otg_ctrl->id || otg_ctrl->a_clr_err
391 		    || otg_ctrl->a_bus_drop) {
392 			otg_ctrl->a_clr_err = 0;
393 			mvotg->phy.otg->state = OTG_STATE_A_WAIT_VFALL;
394 		}
395 		break;
396 	default:
397 		break;
398 	}
399 }
400 
401 static void mv_otg_work(struct work_struct *work)
402 {
403 	struct mv_otg *mvotg;
404 	struct usb_phy *phy;
405 	struct usb_otg *otg;
406 	int old_state;
407 
408 	mvotg = container_of(to_delayed_work(work), struct mv_otg, work);
409 
410 run:
411 	/* work queue is single thread, or we need spin_lock to protect */
412 	phy = &mvotg->phy;
413 	otg = mvotg->phy.otg;
414 	old_state = otg->state;
415 
416 	if (!mvotg->active)
417 		return;
418 
419 	mv_otg_update_inputs(mvotg);
420 	mv_otg_update_state(mvotg);
421 
422 	if (old_state != mvotg->phy.otg->state) {
423 		dev_info(&mvotg->pdev->dev, "change from state %s to %s\n",
424 			 state_string[old_state],
425 			 state_string[mvotg->phy.otg->state]);
426 
427 		switch (mvotg->phy.otg->state) {
428 		case OTG_STATE_B_IDLE:
429 			otg->default_a = 0;
430 			if (old_state == OTG_STATE_B_PERIPHERAL)
431 				mv_otg_start_periphrals(mvotg, 0);
432 			mv_otg_reset(mvotg);
433 			mv_otg_disable(mvotg);
434 			usb_phy_set_event(&mvotg->phy, USB_EVENT_NONE);
435 			break;
436 		case OTG_STATE_B_PERIPHERAL:
437 			mv_otg_enable(mvotg);
438 			mv_otg_start_periphrals(mvotg, 1);
439 			usb_phy_set_event(&mvotg->phy, USB_EVENT_ENUMERATED);
440 			break;
441 		case OTG_STATE_A_IDLE:
442 			otg->default_a = 1;
443 			mv_otg_enable(mvotg);
444 			if (old_state == OTG_STATE_A_WAIT_VFALL)
445 				mv_otg_start_host(mvotg, 0);
446 			mv_otg_reset(mvotg);
447 			break;
448 		case OTG_STATE_A_WAIT_VRISE:
449 			mv_otg_set_vbus(otg, 1);
450 			break;
451 		case OTG_STATE_A_WAIT_BCON:
452 			if (old_state != OTG_STATE_A_HOST)
453 				mv_otg_start_host(mvotg, 1);
454 			mv_otg_set_timer(mvotg, A_WAIT_BCON_TIMER,
455 					 T_A_WAIT_BCON);
456 			/*
457 			 * Now, we directly enter A_HOST. So set b_conn = 1
458 			 * here. In fact, it need host driver to notify us.
459 			 */
460 			mvotg->otg_ctrl.b_conn = 1;
461 			break;
462 		case OTG_STATE_A_HOST:
463 			break;
464 		case OTG_STATE_A_WAIT_VFALL:
465 			/*
466 			 * Now, we has exited A_HOST. So set b_conn = 0
467 			 * here. In fact, it need host driver to notify us.
468 			 */
469 			mvotg->otg_ctrl.b_conn = 0;
470 			mv_otg_set_vbus(otg, 0);
471 			break;
472 		case OTG_STATE_A_VBUS_ERR:
473 			break;
474 		default:
475 			break;
476 		}
477 		goto run;
478 	}
479 }
480 
481 static irqreturn_t mv_otg_irq(int irq, void *dev)
482 {
483 	struct mv_otg *mvotg = dev;
484 	u32 otgsc;
485 
486 	otgsc = readl(&mvotg->op_regs->otgsc);
487 	writel(otgsc, &mvotg->op_regs->otgsc);
488 
489 	/*
490 	 * if we have vbus, then the vbus detection for B-device
491 	 * will be done by mv_otg_inputs_irq().
492 	 */
493 	if (mvotg->pdata->vbus)
494 		if ((otgsc & OTGSC_STS_USB_ID) &&
495 		    !(otgsc & OTGSC_INTSTS_USB_ID))
496 			return IRQ_NONE;
497 
498 	if ((otgsc & mvotg->irq_status) == 0)
499 		return IRQ_NONE;
500 
501 	mv_otg_run_state_machine(mvotg, 0);
502 
503 	return IRQ_HANDLED;
504 }
505 
506 static irqreturn_t mv_otg_inputs_irq(int irq, void *dev)
507 {
508 	struct mv_otg *mvotg = dev;
509 
510 	/* The clock may disabled at this time */
511 	if (!mvotg->active) {
512 		mv_otg_enable(mvotg);
513 		mv_otg_init_irq(mvotg);
514 	}
515 
516 	mv_otg_run_state_machine(mvotg, 0);
517 
518 	return IRQ_HANDLED;
519 }
520 
521 static ssize_t
522 a_bus_req_show(struct device *dev, struct device_attribute *attr, char *buf)
523 {
524 	struct mv_otg *mvotg = dev_get_drvdata(dev);
525 	return scnprintf(buf, PAGE_SIZE, "%d\n",
526 			 mvotg->otg_ctrl.a_bus_req);
527 }
528 
529 static ssize_t
530 a_bus_req_store(struct device *dev, struct device_attribute *attr,
531 	      const char *buf, size_t count)
532 {
533 	struct mv_otg *mvotg = dev_get_drvdata(dev);
534 
535 	if (count > 2)
536 		return -1;
537 
538 	/* We will use this interface to change to A device */
539 	if (mvotg->phy.otg->state != OTG_STATE_B_IDLE
540 	    && mvotg->phy.otg->state != OTG_STATE_A_IDLE)
541 		return -1;
542 
543 	/* The clock may disabled and we need to set irq for ID detected */
544 	mv_otg_enable(mvotg);
545 	mv_otg_init_irq(mvotg);
546 
547 	if (buf[0] == '1') {
548 		mvotg->otg_ctrl.a_bus_req = 1;
549 		mvotg->otg_ctrl.a_bus_drop = 0;
550 		dev_dbg(&mvotg->pdev->dev,
551 			"User request: a_bus_req = 1\n");
552 
553 		if (spin_trylock(&mvotg->wq_lock)) {
554 			mv_otg_run_state_machine(mvotg, 0);
555 			spin_unlock(&mvotg->wq_lock);
556 		}
557 	}
558 
559 	return count;
560 }
561 
562 static DEVICE_ATTR_RW(a_bus_req);
563 
564 static ssize_t
565 a_clr_err_store(struct device *dev, struct device_attribute *attr,
566 	      const char *buf, size_t count)
567 {
568 	struct mv_otg *mvotg = dev_get_drvdata(dev);
569 	if (!mvotg->phy.otg->default_a)
570 		return -1;
571 
572 	if (count > 2)
573 		return -1;
574 
575 	if (buf[0] == '1') {
576 		mvotg->otg_ctrl.a_clr_err = 1;
577 		dev_dbg(&mvotg->pdev->dev,
578 			"User request: a_clr_err = 1\n");
579 	}
580 
581 	if (spin_trylock(&mvotg->wq_lock)) {
582 		mv_otg_run_state_machine(mvotg, 0);
583 		spin_unlock(&mvotg->wq_lock);
584 	}
585 
586 	return count;
587 }
588 
589 static DEVICE_ATTR_WO(a_clr_err);
590 
591 static ssize_t
592 a_bus_drop_show(struct device *dev, struct device_attribute *attr,
593 	       char *buf)
594 {
595 	struct mv_otg *mvotg = dev_get_drvdata(dev);
596 	return scnprintf(buf, PAGE_SIZE, "%d\n",
597 			 mvotg->otg_ctrl.a_bus_drop);
598 }
599 
600 static ssize_t
601 a_bus_drop_store(struct device *dev, struct device_attribute *attr,
602 	       const char *buf, size_t count)
603 {
604 	struct mv_otg *mvotg = dev_get_drvdata(dev);
605 	if (!mvotg->phy.otg->default_a)
606 		return -1;
607 
608 	if (count > 2)
609 		return -1;
610 
611 	if (buf[0] == '0') {
612 		mvotg->otg_ctrl.a_bus_drop = 0;
613 		dev_dbg(&mvotg->pdev->dev,
614 			"User request: a_bus_drop = 0\n");
615 	} else if (buf[0] == '1') {
616 		mvotg->otg_ctrl.a_bus_drop = 1;
617 		mvotg->otg_ctrl.a_bus_req = 0;
618 		dev_dbg(&mvotg->pdev->dev,
619 			"User request: a_bus_drop = 1\n");
620 		dev_dbg(&mvotg->pdev->dev,
621 			"User request: and a_bus_req = 0\n");
622 	}
623 
624 	if (spin_trylock(&mvotg->wq_lock)) {
625 		mv_otg_run_state_machine(mvotg, 0);
626 		spin_unlock(&mvotg->wq_lock);
627 	}
628 
629 	return count;
630 }
631 
632 static DEVICE_ATTR_RW(a_bus_drop);
633 
634 static struct attribute *inputs_attrs[] = {
635 	&dev_attr_a_bus_req.attr,
636 	&dev_attr_a_clr_err.attr,
637 	&dev_attr_a_bus_drop.attr,
638 	NULL,
639 };
640 
641 static const struct attribute_group inputs_attr_group = {
642 	.name = "inputs",
643 	.attrs = inputs_attrs,
644 };
645 
646 static int mv_otg_remove(struct platform_device *pdev)
647 {
648 	struct mv_otg *mvotg = platform_get_drvdata(pdev);
649 
650 	sysfs_remove_group(&mvotg->pdev->dev.kobj, &inputs_attr_group);
651 
652 	if (mvotg->qwork) {
653 		flush_workqueue(mvotg->qwork);
654 		destroy_workqueue(mvotg->qwork);
655 	}
656 
657 	mv_otg_disable(mvotg);
658 
659 	usb_remove_phy(&mvotg->phy);
660 
661 	return 0;
662 }
663 
664 static int mv_otg_probe(struct platform_device *pdev)
665 {
666 	struct mv_usb_platform_data *pdata = dev_get_platdata(&pdev->dev);
667 	struct mv_otg *mvotg;
668 	struct usb_otg *otg;
669 	struct resource *r;
670 	int retval = 0, i;
671 
672 	if (pdata == NULL) {
673 		dev_err(&pdev->dev, "failed to get platform data\n");
674 		return -ENODEV;
675 	}
676 
677 	mvotg = devm_kzalloc(&pdev->dev, sizeof(*mvotg), GFP_KERNEL);
678 	if (!mvotg)
679 		return -ENOMEM;
680 
681 	otg = devm_kzalloc(&pdev->dev, sizeof(*otg), GFP_KERNEL);
682 	if (!otg)
683 		return -ENOMEM;
684 
685 	platform_set_drvdata(pdev, mvotg);
686 
687 	mvotg->pdev = pdev;
688 	mvotg->pdata = pdata;
689 
690 	mvotg->clk = devm_clk_get(&pdev->dev, NULL);
691 	if (IS_ERR(mvotg->clk))
692 		return PTR_ERR(mvotg->clk);
693 
694 	mvotg->qwork = create_singlethread_workqueue("mv_otg_queue");
695 	if (!mvotg->qwork) {
696 		dev_dbg(&pdev->dev, "cannot create workqueue for OTG\n");
697 		return -ENOMEM;
698 	}
699 
700 	INIT_DELAYED_WORK(&mvotg->work, mv_otg_work);
701 
702 	/* OTG common part */
703 	mvotg->pdev = pdev;
704 	mvotg->phy.dev = &pdev->dev;
705 	mvotg->phy.otg = otg;
706 	mvotg->phy.label = driver_name;
707 
708 	otg->state = OTG_STATE_UNDEFINED;
709 	otg->usb_phy = &mvotg->phy;
710 	otg->set_host = mv_otg_set_host;
711 	otg->set_peripheral = mv_otg_set_peripheral;
712 	otg->set_vbus = mv_otg_set_vbus;
713 
714 	for (i = 0; i < OTG_TIMER_NUM; i++)
715 		timer_setup(&mvotg->otg_ctrl.timer[i],
716 			    mv_otg_timer_await_bcon, 0);
717 
718 	r = platform_get_resource_byname(mvotg->pdev,
719 					 IORESOURCE_MEM, "phyregs");
720 	if (r == NULL) {
721 		dev_err(&pdev->dev, "no phy I/O memory resource defined\n");
722 		retval = -ENODEV;
723 		goto err_destroy_workqueue;
724 	}
725 
726 	mvotg->phy_regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
727 	if (mvotg->phy_regs == NULL) {
728 		dev_err(&pdev->dev, "failed to map phy I/O memory\n");
729 		retval = -EFAULT;
730 		goto err_destroy_workqueue;
731 	}
732 
733 	r = platform_get_resource_byname(mvotg->pdev,
734 					 IORESOURCE_MEM, "capregs");
735 	if (r == NULL) {
736 		dev_err(&pdev->dev, "no I/O memory resource defined\n");
737 		retval = -ENODEV;
738 		goto err_destroy_workqueue;
739 	}
740 
741 	mvotg->cap_regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
742 	if (mvotg->cap_regs == NULL) {
743 		dev_err(&pdev->dev, "failed to map I/O memory\n");
744 		retval = -EFAULT;
745 		goto err_destroy_workqueue;
746 	}
747 
748 	/* we will acces controller register, so enable the udc controller */
749 	retval = mv_otg_enable_internal(mvotg);
750 	if (retval) {
751 		dev_err(&pdev->dev, "mv otg enable error %d\n", retval);
752 		goto err_destroy_workqueue;
753 	}
754 
755 	mvotg->op_regs =
756 		(struct mv_otg_regs __iomem *) ((unsigned long) mvotg->cap_regs
757 			+ (readl(mvotg->cap_regs) & CAPLENGTH_MASK));
758 
759 	if (pdata->id) {
760 		retval = devm_request_threaded_irq(&pdev->dev, pdata->id->irq,
761 						NULL, mv_otg_inputs_irq,
762 						IRQF_ONESHOT, "id", mvotg);
763 		if (retval) {
764 			dev_info(&pdev->dev,
765 				 "Failed to request irq for ID\n");
766 			pdata->id = NULL;
767 		}
768 	}
769 
770 	if (pdata->vbus) {
771 		mvotg->clock_gating = 1;
772 		retval = devm_request_threaded_irq(&pdev->dev, pdata->vbus->irq,
773 						NULL, mv_otg_inputs_irq,
774 						IRQF_ONESHOT, "vbus", mvotg);
775 		if (retval) {
776 			dev_info(&pdev->dev,
777 				 "Failed to request irq for VBUS, "
778 				 "disable clock gating\n");
779 			mvotg->clock_gating = 0;
780 			pdata->vbus = NULL;
781 		}
782 	}
783 
784 	if (pdata->disable_otg_clock_gating)
785 		mvotg->clock_gating = 0;
786 
787 	mv_otg_reset(mvotg);
788 	mv_otg_init_irq(mvotg);
789 
790 	r = platform_get_resource(mvotg->pdev, IORESOURCE_IRQ, 0);
791 	if (r == NULL) {
792 		dev_err(&pdev->dev, "no IRQ resource defined\n");
793 		retval = -ENODEV;
794 		goto err_disable_clk;
795 	}
796 
797 	mvotg->irq = r->start;
798 	if (devm_request_irq(&pdev->dev, mvotg->irq, mv_otg_irq, IRQF_SHARED,
799 			driver_name, mvotg)) {
800 		dev_err(&pdev->dev, "Request irq %d for OTG failed\n",
801 			mvotg->irq);
802 		mvotg->irq = 0;
803 		retval = -ENODEV;
804 		goto err_disable_clk;
805 	}
806 
807 	retval = usb_add_phy(&mvotg->phy, USB_PHY_TYPE_USB2);
808 	if (retval < 0) {
809 		dev_err(&pdev->dev, "can't register transceiver, %d\n",
810 			retval);
811 		goto err_disable_clk;
812 	}
813 
814 	retval = sysfs_create_group(&pdev->dev.kobj, &inputs_attr_group);
815 	if (retval < 0) {
816 		dev_dbg(&pdev->dev,
817 			"Can't register sysfs attr group: %d\n", retval);
818 		goto err_remove_phy;
819 	}
820 
821 	spin_lock_init(&mvotg->wq_lock);
822 	if (spin_trylock(&mvotg->wq_lock)) {
823 		mv_otg_run_state_machine(mvotg, 2 * HZ);
824 		spin_unlock(&mvotg->wq_lock);
825 	}
826 
827 	dev_info(&pdev->dev,
828 		 "successful probe OTG device %s clock gating.\n",
829 		 mvotg->clock_gating ? "with" : "without");
830 
831 	return 0;
832 
833 err_remove_phy:
834 	usb_remove_phy(&mvotg->phy);
835 err_disable_clk:
836 	mv_otg_disable_internal(mvotg);
837 err_destroy_workqueue:
838 	flush_workqueue(mvotg->qwork);
839 	destroy_workqueue(mvotg->qwork);
840 
841 	return retval;
842 }
843 
844 #ifdef CONFIG_PM
845 static int mv_otg_suspend(struct platform_device *pdev, pm_message_t state)
846 {
847 	struct mv_otg *mvotg = platform_get_drvdata(pdev);
848 
849 	if (mvotg->phy.otg->state != OTG_STATE_B_IDLE) {
850 		dev_info(&pdev->dev,
851 			 "OTG state is not B_IDLE, it is %d!\n",
852 			 mvotg->phy.otg->state);
853 		return -EAGAIN;
854 	}
855 
856 	if (!mvotg->clock_gating)
857 		mv_otg_disable_internal(mvotg);
858 
859 	return 0;
860 }
861 
862 static int mv_otg_resume(struct platform_device *pdev)
863 {
864 	struct mv_otg *mvotg = platform_get_drvdata(pdev);
865 	u32 otgsc;
866 
867 	if (!mvotg->clock_gating) {
868 		mv_otg_enable_internal(mvotg);
869 
870 		otgsc = readl(&mvotg->op_regs->otgsc);
871 		otgsc |= mvotg->irq_en;
872 		writel(otgsc, &mvotg->op_regs->otgsc);
873 
874 		if (spin_trylock(&mvotg->wq_lock)) {
875 			mv_otg_run_state_machine(mvotg, 0);
876 			spin_unlock(&mvotg->wq_lock);
877 		}
878 	}
879 	return 0;
880 }
881 #endif
882 
883 static struct platform_driver mv_otg_driver = {
884 	.probe = mv_otg_probe,
885 	.remove = mv_otg_remove,
886 	.driver = {
887 		   .name = driver_name,
888 		   },
889 #ifdef CONFIG_PM
890 	.suspend = mv_otg_suspend,
891 	.resume = mv_otg_resume,
892 #endif
893 };
894 module_platform_driver(mv_otg_driver);
895