phy-gpio-vbus-usb.c revision 94ae98433a397dd4695652fc62ca7bc784b08216 
1/*
2 * gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices
3 *
4 * Copyright (c) 2008 Philipp Zabel <philipp.zabel@gmail.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/kernel.h>
12#include <linux/platform_device.h>
13#include <linux/gpio.h>
14#include <linux/module.h>
15#include <linux/slab.h>
16#include <linux/interrupt.h>
17#include <linux/usb.h>
18#include <linux/workqueue.h>
19
20#include <linux/regulator/consumer.h>
21
22#include <linux/usb/gadget.h>
23#include <linux/usb/gpio_vbus.h>
24#include <linux/usb/otg.h>
25
26
27/*
28 * A simple GPIO VBUS sensing driver for B peripheral only devices
29 * with internal transceivers. It can control a D+ pullup GPIO and
30 * a regulator to limit the current drawn from VBUS.
31 *
32 * Needs to be loaded before the UDC driver that will use it.
33 */
34struct gpio_vbus_data {
35	struct usb_phy		phy;
36	struct device          *dev;
37	struct regulator       *vbus_draw;
38	int			vbus_draw_enabled;
39	unsigned		mA;
40	struct delayed_work	work;
41	int			vbus;
42	int			irq;
43};
44
45
46/*
47 * This driver relies on "both edges" triggering.  VBUS has 100 msec to
48 * stabilize, so the peripheral controller driver may need to cope with
49 * some bouncing due to current surges (e.g. charging local capacitance)
50 * and contact chatter.
51 *
52 * REVISIT in desperate straits, toggling between rising and falling
53 * edges might be workable.
54 */
55#define VBUS_IRQ_FLAGS \
56	(IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
57
58
59/* interface to regulator framework */
60static void set_vbus_draw(struct gpio_vbus_data *gpio_vbus, unsigned mA)
61{
62	struct regulator *vbus_draw = gpio_vbus->vbus_draw;
63	int enabled;
64
65	if (!vbus_draw)
66		return;
67
68	enabled = gpio_vbus->vbus_draw_enabled;
69	if (mA) {
70		regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
71		if (!enabled) {
72			regulator_enable(vbus_draw);
73			gpio_vbus->vbus_draw_enabled = 1;
74		}
75	} else {
76		if (enabled) {
77			regulator_disable(vbus_draw);
78			gpio_vbus->vbus_draw_enabled = 0;
79		}
80	}
81	gpio_vbus->mA = mA;
82}
83
84static int is_vbus_powered(struct gpio_vbus_mach_info *pdata)
85{
86	int vbus;
87
88	vbus = gpio_get_value(pdata->gpio_vbus);
89	if (pdata->gpio_vbus_inverted)
90		vbus = !vbus;
91
92	return vbus;
93}
94
95static void gpio_vbus_work(struct work_struct *work)
96{
97	struct gpio_vbus_data *gpio_vbus =
98		container_of(work, struct gpio_vbus_data, work.work);
99	struct gpio_vbus_mach_info *pdata = gpio_vbus->dev->platform_data;
100	int gpio, status, vbus;
101
102	if (!gpio_vbus->phy.otg->gadget)
103		return;
104
105	vbus = is_vbus_powered(pdata);
106	if ((vbus ^ gpio_vbus->vbus) == 0)
107		return;
108	gpio_vbus->vbus = vbus;
109
110	/* Peripheral controllers which manage the pullup themselves won't have
111	 * gpio_pullup configured here.  If it's configured here, we'll do what
112	 * isp1301_omap::b_peripheral() does and enable the pullup here... although
113	 * that may complicate usb_gadget_{,dis}connect() support.
114	 */
115	gpio = pdata->gpio_pullup;
116
117	if (vbus) {
118		status = USB_EVENT_VBUS;
119		gpio_vbus->phy.state = OTG_STATE_B_PERIPHERAL;
120		gpio_vbus->phy.last_event = status;
121		usb_gadget_vbus_connect(gpio_vbus->phy.otg->gadget);
122
123		/* drawing a "unit load" is *always* OK, except for OTG */
124		set_vbus_draw(gpio_vbus, 100);
125
126		/* optionally enable D+ pullup */
127		if (gpio_is_valid(gpio))
128			gpio_set_value(gpio, !pdata->gpio_pullup_inverted);
129
130		atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
131					   status, gpio_vbus->phy.otg->gadget);
132	} else {
133		/* optionally disable D+ pullup */
134		if (gpio_is_valid(gpio))
135			gpio_set_value(gpio, pdata->gpio_pullup_inverted);
136
137		set_vbus_draw(gpio_vbus, 0);
138
139		usb_gadget_vbus_disconnect(gpio_vbus->phy.otg->gadget);
140		status = USB_EVENT_NONE;
141		gpio_vbus->phy.state = OTG_STATE_B_IDLE;
142		gpio_vbus->phy.last_event = status;
143
144		atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
145					   status, gpio_vbus->phy.otg->gadget);
146	}
147}
148
149/* VBUS change IRQ handler */
150static irqreturn_t gpio_vbus_irq(int irq, void *data)
151{
152	struct platform_device *pdev = data;
153	struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
154	struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
155	struct usb_otg *otg = gpio_vbus->phy.otg;
156
157	dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
158		is_vbus_powered(pdata) ? "supplied" : "inactive",
159		otg->gadget ? otg->gadget->name : "none");
160
161	if (otg->gadget)
162		schedule_delayed_work(&gpio_vbus->work, msecs_to_jiffies(100));
163
164	return IRQ_HANDLED;
165}
166
167/* OTG transceiver interface */
168
169/* bind/unbind the peripheral controller */
170static int gpio_vbus_set_peripheral(struct usb_otg *otg,
171					struct usb_gadget *gadget)
172{
173	struct gpio_vbus_data *gpio_vbus;
174	struct gpio_vbus_mach_info *pdata;
175	struct platform_device *pdev;
176	int gpio;
177
178	gpio_vbus = container_of(otg->phy, struct gpio_vbus_data, phy);
179	pdev = to_platform_device(gpio_vbus->dev);
180	pdata = gpio_vbus->dev->platform_data;
181	gpio = pdata->gpio_pullup;
182
183	if (!gadget) {
184		dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
185			otg->gadget->name);
186
187		/* optionally disable D+ pullup */
188		if (gpio_is_valid(gpio))
189			gpio_set_value(gpio, pdata->gpio_pullup_inverted);
190
191		set_vbus_draw(gpio_vbus, 0);
192
193		usb_gadget_vbus_disconnect(otg->gadget);
194		otg->phy->state = OTG_STATE_UNDEFINED;
195
196		otg->gadget = NULL;
197		return 0;
198	}
199
200	otg->gadget = gadget;
201	dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
202
203	/* initialize connection state */
204	gpio_vbus->vbus = 0; /* start with disconnected */
205	gpio_vbus_irq(gpio_vbus->irq, pdev);
206	return 0;
207}
208
209/* effective for B devices, ignored for A-peripheral */
210static int gpio_vbus_set_power(struct usb_phy *phy, unsigned mA)
211{
212	struct gpio_vbus_data *gpio_vbus;
213
214	gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
215
216	if (phy->state == OTG_STATE_B_PERIPHERAL)
217		set_vbus_draw(gpio_vbus, mA);
218	return 0;
219}
220
221/* for non-OTG B devices: set/clear transceiver suspend mode */
222static int gpio_vbus_set_suspend(struct usb_phy *phy, int suspend)
223{
224	struct gpio_vbus_data *gpio_vbus;
225
226	gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
227
228	/* draw max 0 mA from vbus in suspend mode; or the previously
229	 * recorded amount of current if not suspended
230	 *
231	 * NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
232	 * if they're wake-enabled ... we don't handle that yet.
233	 */
234	return gpio_vbus_set_power(phy, suspend ? 0 : gpio_vbus->mA);
235}
236
237/* platform driver interface */
238
239static int __init gpio_vbus_probe(struct platform_device *pdev)
240{
241	struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
242	struct gpio_vbus_data *gpio_vbus;
243	struct resource *res;
244	int err, gpio, irq;
245	unsigned long irqflags;
246
247	if (!pdata || !gpio_is_valid(pdata->gpio_vbus))
248		return -EINVAL;
249	gpio = pdata->gpio_vbus;
250
251	gpio_vbus = kzalloc(sizeof(struct gpio_vbus_data), GFP_KERNEL);
252	if (!gpio_vbus)
253		return -ENOMEM;
254
255	gpio_vbus->phy.otg = kzalloc(sizeof(struct usb_otg), GFP_KERNEL);
256	if (!gpio_vbus->phy.otg) {
257		kfree(gpio_vbus);
258		return -ENOMEM;
259	}
260
261	platform_set_drvdata(pdev, gpio_vbus);
262	gpio_vbus->dev = &pdev->dev;
263	gpio_vbus->phy.label = "gpio-vbus";
264	gpio_vbus->phy.set_power = gpio_vbus_set_power;
265	gpio_vbus->phy.set_suspend = gpio_vbus_set_suspend;
266	gpio_vbus->phy.state = OTG_STATE_UNDEFINED;
267
268	gpio_vbus->phy.otg->phy = &gpio_vbus->phy;
269	gpio_vbus->phy.otg->set_peripheral = gpio_vbus_set_peripheral;
270
271	err = gpio_request(gpio, "vbus_detect");
272	if (err) {
273		dev_err(&pdev->dev, "can't request vbus gpio %d, err: %d\n",
274			gpio, err);
275		goto err_gpio;
276	}
277	gpio_direction_input(gpio);
278
279	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
280	if (res) {
281		irq = res->start;
282		irqflags = (res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
283	} else {
284		irq = gpio_to_irq(gpio);
285		irqflags = VBUS_IRQ_FLAGS;
286	}
287
288	gpio_vbus->irq = irq;
289
290	/* if data line pullup is in use, initialize it to "not pulling up" */
291	gpio = pdata->gpio_pullup;
292	if (gpio_is_valid(gpio)) {
293		err = gpio_request(gpio, "udc_pullup");
294		if (err) {
295			dev_err(&pdev->dev,
296				"can't request pullup gpio %d, err: %d\n",
297				gpio, err);
298			gpio_free(pdata->gpio_vbus);
299			goto err_gpio;
300		}
301		gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
302	}
303
304	err = request_irq(irq, gpio_vbus_irq, irqflags, "vbus_detect", pdev);
305	if (err) {
306		dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
307			irq, err);
308		goto err_irq;
309	}
310
311	ATOMIC_INIT_NOTIFIER_HEAD(&gpio_vbus->phy.notifier);
312
313	INIT_DELAYED_WORK(&gpio_vbus->work, gpio_vbus_work);
314
315	gpio_vbus->vbus_draw = regulator_get(&pdev->dev, "vbus_draw");
316	if (IS_ERR(gpio_vbus->vbus_draw)) {
317		dev_dbg(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
318			PTR_ERR(gpio_vbus->vbus_draw));
319		gpio_vbus->vbus_draw = NULL;
320	}
321
322	/* only active when a gadget is registered */
323	err = usb_add_phy(&gpio_vbus->phy, USB_PHY_TYPE_USB2);
324	if (err) {
325		dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
326			err);
327		goto err_otg;
328	}
329
330	device_init_wakeup(&pdev->dev, pdata->wakeup);
331
332	return 0;
333err_otg:
334	regulator_put(gpio_vbus->vbus_draw);
335	free_irq(irq, pdev);
336err_irq:
337	if (gpio_is_valid(pdata->gpio_pullup))
338		gpio_free(pdata->gpio_pullup);
339	gpio_free(pdata->gpio_vbus);
340err_gpio:
341	platform_set_drvdata(pdev, NULL);
342	kfree(gpio_vbus->phy.otg);
343	kfree(gpio_vbus);
344	return err;
345}
346
347static int __exit gpio_vbus_remove(struct platform_device *pdev)
348{
349	struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
350	struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
351	int gpio = pdata->gpio_vbus;
352
353	device_init_wakeup(&pdev->dev, 0);
354	cancel_delayed_work_sync(&gpio_vbus->work);
355	regulator_put(gpio_vbus->vbus_draw);
356
357	usb_remove_phy(&gpio_vbus->phy);
358
359	free_irq(gpio_vbus->irq, pdev);
360	if (gpio_is_valid(pdata->gpio_pullup))
361		gpio_free(pdata->gpio_pullup);
362	gpio_free(gpio);
363	platform_set_drvdata(pdev, NULL);
364	kfree(gpio_vbus->phy.otg);
365	kfree(gpio_vbus);
366
367	return 0;
368}
369
370#ifdef CONFIG_PM
371static int gpio_vbus_pm_suspend(struct device *dev)
372{
373	struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
374
375	if (device_may_wakeup(dev))
376		enable_irq_wake(gpio_vbus->irq);
377
378	return 0;
379}
380
381static int gpio_vbus_pm_resume(struct device *dev)
382{
383	struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
384
385	if (device_may_wakeup(dev))
386		disable_irq_wake(gpio_vbus->irq);
387
388	return 0;
389}
390
391static const struct dev_pm_ops gpio_vbus_dev_pm_ops = {
392	.suspend	= gpio_vbus_pm_suspend,
393	.resume		= gpio_vbus_pm_resume,
394};
395#endif
396
397/* NOTE:  the gpio-vbus device may *NOT* be hotplugged */
398
399MODULE_ALIAS("platform:gpio-vbus");
400
401static struct platform_driver gpio_vbus_driver = {
402	.driver = {
403		.name  = "gpio-vbus",
404		.owner = THIS_MODULE,
405#ifdef CONFIG_PM
406		.pm = &gpio_vbus_dev_pm_ops,
407#endif
408	},
409	.remove  = __exit_p(gpio_vbus_remove),
410};
411
412module_platform_driver_probe(gpio_vbus_driver, gpio_vbus_probe);
413
414MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
415MODULE_AUTHOR("Philipp Zabel");
416MODULE_LICENSE("GPL");
417