aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/usb/otg/gpio_vbus.c
blob: a67ffe22179a5719674e236cbe322260da1e43e9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
/*
 * gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices
 *
 * Copyright (c) 2008 Philipp Zabel <philipp.zabel@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/usb.h>
#include <linux/workqueue.h>

#include <linux/regulator/consumer.h>

#include <linux/usb/gadget.h>
#include <linux/usb/gpio_vbus.h>
#include <linux/usb/otg.h>


/*
 * A simple GPIO VBUS sensing driver for B peripheral only devices
 * with internal transceivers. It can control a D+ pullup GPIO and
 * a regulator to limit the current drawn from VBUS.
 *
 * Needs to be loaded before the UDC driver that will use it.
 */
struct gpio_vbus_data {
	struct usb_phy		phy;
	struct device          *dev;
	struct regulator       *vbus_draw;
	int			vbus_draw_enabled;
	unsigned		mA;
	struct delayed_work	work;
	int			vbus;
	int			irq;
};


/*
 * This driver relies on "both edges" triggering.  VBUS has 100 msec to
 * stabilize, so the peripheral controller driver may need to cope with
 * some bouncing due to current surges (e.g. charging local capacitance)
 * and contact chatter.
 *
 * REVISIT in desperate straits, toggling between rising and falling
 * edges might be workable.
 */
#define VBUS_IRQ_FLAGS \
	(IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)


/* interface to regulator framework */
static void set_vbus_draw(struct gpio_vbus_data *gpio_vbus, unsigned mA)
{
	struct regulator *vbus_draw = gpio_vbus->vbus_draw;
	int enabled;

	if (!vbus_draw)
		return;

	enabled = gpio_vbus->vbus_draw_enabled;
	if (mA) {
		regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
		if (!enabled) {
			regulator_enable(vbus_draw);
			gpio_vbus->vbus_draw_enabled = 1;
		}
	} else {
		if (enabled) {
			regulator_disable(vbus_draw);
			gpio_vbus->vbus_draw_enabled = 0;
		}
	}
	gpio_vbus->mA = mA;
}

static int is_vbus_powered(struct gpio_vbus_mach_info *pdata)
{
	int vbus;

	vbus = gpio_get_value(pdata->gpio_vbus);
	if (pdata->gpio_vbus_inverted)
		vbus = !vbus;

	return vbus;
}

static void gpio_vbus_work(struct work_struct *work)
{
	struct gpio_vbus_data *gpio_vbus =
		container_of(work, struct gpio_vbus_data, work.work);
	struct gpio_vbus_mach_info *pdata = gpio_vbus->dev->platform_data;
	int gpio, status, vbus;

	if (!gpio_vbus->phy.otg->gadget)
		return;

	vbus = is_vbus_powered(pdata);
	if ((vbus ^ gpio_vbus->vbus) == 0)
		return;
	gpio_vbus->vbus = vbus;

	/* Peripheral controllers which manage the pullup themselves won't have
	 * gpio_pullup configured here.  If it's configured here, we'll do what
	 * isp1301_omap::b_peripheral() does and enable the pullup here... although
	 * that may complicate usb_gadget_{,dis}connect() support.
	 */
	gpio = pdata->gpio_pullup;

	if (vbus) {
		status = USB_EVENT_VBUS;
		gpio_vbus->phy.state = OTG_STATE_B_PERIPHERAL;
		gpio_vbus->phy.last_event = status;
		usb_gadget_vbus_connect(gpio_vbus->phy.otg->gadget);

		/* drawing a "unit load" is *always* OK, except for OTG */
		set_vbus_draw(gpio_vbus, 100);

		/* optionally enable D+ pullup */
		if (gpio_is_valid(gpio))
			gpio_set_value(gpio, !pdata->gpio_pullup_inverted);

		atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
					   status, gpio_vbus->phy.otg->gadget);
	} else {
		/* optionally disable D+ pullup */
		if (gpio_is_valid(gpio))
			gpio_set_value(gpio, pdata->gpio_pullup_inverted);

		set_vbus_draw(gpio_vbus, 0);

		usb_gadget_vbus_disconnect(gpio_vbus->phy.otg->gadget);
		status = USB_EVENT_NONE;
		gpio_vbus->phy.state = OTG_STATE_B_IDLE;
		gpio_vbus->phy.last_event = status;

		atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
					   status, gpio_vbus->phy.otg->gadget);
	}
}

/* VBUS change IRQ handler */
static irqreturn_t gpio_vbus_irq(int irq, void *data)
{
	struct platform_device *pdev = data;
	struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
	struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
	struct usb_otg *otg = gpio_vbus->phy.otg;

	dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
		is_vbus_powered(pdata) ? "supplied" : "inactive",
		otg->gadget ? otg->gadget->name : "none");

	if (otg->gadget)
		schedule_delayed_work(&gpio_vbus->work, msecs_to_jiffies(100));

	return IRQ_HANDLED;
}

/* OTG transceiver interface */

/* bind/unbind the peripheral controller */
static int gpio_vbus_set_peripheral(struct usb_otg *otg,
					struct usb_gadget *gadget)
{
	struct gpio_vbus_data *gpio_vbus;
	struct gpio_vbus_mach_info *pdata;
	struct platform_device *pdev;
	int gpio;

	gpio_vbus = container_of(otg->phy, struct gpio_vbus_data, phy);
	pdev = to_platform_device(gpio_vbus->dev);
	pdata = gpio_vbus->dev->platform_data;
	gpio = pdata->gpio_pullup;

	if (!gadget) {
		dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
			otg->gadget->name);

		/* optionally disable D+ pullup */
		if (gpio_is_valid(gpio))
			gpio_set_value(gpio, pdata->gpio_pullup_inverted);

		set_vbus_draw(gpio_vbus, 0);

		usb_gadget_vbus_disconnect(otg->gadget);
		otg->phy->state = OTG_STATE_UNDEFINED;

		otg->gadget = NULL;
		return 0;
	}

	otg->gadget = gadget;
	dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);

	/* initialize connection state */
	gpio_vbus->vbus = 0; /* start with disconnected */
	gpio_vbus_irq(gpio_vbus->irq, pdev);
	return 0;
}

/* effective for B devices, ignored for A-peripheral */
static int gpio_vbus_set_power(struct usb_phy *phy, unsigned mA)
{
	struct gpio_vbus_data *gpio_vbus;

	gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);

	if (phy->state == OTG_STATE_B_PERIPHERAL)
		set_vbus_draw(gpio_vbus, mA);
	return 0;
}

/* for non-OTG B devices: set/clear transceiver suspend mode */
static int gpio_vbus_set_suspend(struct usb_phy *phy, int suspend)
{
	struct gpio_vbus_data *gpio_vbus;

	gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);

	/* draw max 0 mA from vbus in suspend mode; or the previously
	 * recorded amount of current if not suspended
	 *
	 * NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
	 * if they're wake-enabled ... we don't handle that yet.
	 */
	return gpio_vbus_set_power(phy, suspend ? 0 : gpio_vbus->mA);
}

/* platform driver interface */

static int __init gpio_vbus_probe(struct platform_device *pdev)
{
	struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
	struct gpio_vbus_data *gpio_vbus;
	struct resource *res;
	int err, gpio, irq;
	unsigned long irqflags;

	if (!pdata || !gpio_is_valid(pdata->gpio_vbus))
		return -EINVAL;
	gpio = pdata->gpio_vbus;

	gpio_vbus = kzalloc(sizeof(struct gpio_vbus_data), GFP_KERNEL);
	if (!gpio_vbus)
		return -ENOMEM;

	gpio_vbus->phy.otg = kzalloc(sizeof(struct usb_otg), GFP_KERNEL);
	if (!gpio_vbus->phy.otg) {
		kfree(gpio_vbus);
		return -ENOMEM;
	}

	platform_set_drvdata(pdev, gpio_vbus);
	gpio_vbus->dev = &pdev->dev;
	gpio_vbus->phy.label = "gpio-vbus";
	gpio_vbus->phy.set_power = gpio_vbus_set_power;
	gpio_vbus->phy.set_suspend = gpio_vbus_set_suspend;
	gpio_vbus->phy.state = OTG_STATE_UNDEFINED;

	gpio_vbus->phy.otg->phy = &gpio_vbus->phy;
	gpio_vbus->phy.otg->set_peripheral = gpio_vbus_set_peripheral;

	err = gpio_request(gpio, "vbus_detect");
	if (err) {
		dev_err(&pdev->dev, "can't request vbus gpio %d, err: %d\n",
			gpio, err);
		goto err_gpio;
	}
	gpio_direction_input(gpio);

	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (res) {
		irq = res->start;
		irqflags = (res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
	} else {
		irq = gpio_to_irq(gpio);
		irqflags = VBUS_IRQ_FLAGS;
	}

	gpio_vbus->irq = irq;

	/* if data line pullup is in use, initialize it to "not pulling up" */
	gpio = pdata->gpio_pullup;
	if (gpio_is_valid(gpio)) {
		err = gpio_request(gpio, "udc_pullup");
		if (err) {
			dev_err(&pdev->dev,
				"can't request pullup gpio %d, err: %d\n",
				gpio, err);
			gpio_free(pdata->gpio_vbus);
			goto err_gpio;
		}
		gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
	}

	err = request_irq(irq, gpio_vbus_irq, irqflags, "vbus_detect", pdev);
	if (err) {
		dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
			irq, err);
		goto err_irq;
	}

	ATOMIC_INIT_NOTIFIER_HEAD(&gpio_vbus->phy.notifier);

	INIT_DELAYED_WORK(&gpio_vbus->work, gpio_vbus_work);

	gpio_vbus->vbus_draw = regulator_get(&pdev->dev, "vbus_draw");
	if (IS_ERR(gpio_vbus->vbus_draw)) {
		dev_dbg(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
			PTR_ERR(gpio_vbus->vbus_draw));
		gpio_vbus->vbus_draw = NULL;
	}

	/* only active when a gadget is registered */
	err = usb_add_phy(&gpio_vbus->phy, USB_PHY_TYPE_USB2);
	if (err) {
		dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
			err);
		goto err_otg;
	}

	device_init_wakeup(&pdev->dev, pdata->wakeup);

	return 0;
err_otg:
	regulator_put(gpio_vbus->vbus_draw);
	free_irq(irq, pdev);
err_irq:
	if (gpio_is_valid(pdata->gpio_pullup))
		gpio_free(pdata->gpio_pullup);
	gpio_free(pdata->gpio_vbus);
err_gpio:
	platform_set_drvdata(pdev, NULL);
	kfree(gpio_vbus->phy.otg);
	kfree(gpio_vbus);
	return err;
}

static int __exit gpio_vbus_remove(struct platform_device *pdev)
{
	struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
	struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
	int gpio = pdata->gpio_vbus;

	device_init_wakeup(&pdev->dev, 0);
	cancel_delayed_work_sync(&gpio_vbus->work);
	regulator_put(gpio_vbus->vbus_draw);

	usb_remove_phy(&gpio_vbus->phy);

	free_irq(gpio_vbus->irq, pdev);
	if (gpio_is_valid(pdata->gpio_pullup))
		gpio_free(pdata->gpio_pullup);
	gpio_free(gpio);
	platform_set_drvdata(pdev, NULL);
	kfree(gpio_vbus->phy.otg);
	kfree(gpio_vbus);

	return 0;
}

#ifdef CONFIG_PM
static int gpio_vbus_pm_suspend(struct device *dev)
{
	struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
		enable_irq_wake(gpio_vbus->irq);

	return 0;
}

static int gpio_vbus_pm_resume(struct device *dev)
{
	struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
		disable_irq_wake(gpio_vbus->irq);

	return 0;
}

static const struct dev_pm_ops gpio_vbus_dev_pm_ops = {
	.suspend	= gpio_vbus_pm_suspend,
	.resume		= gpio_vbus_pm_resume,
};
#endif

/* NOTE:  the gpio-vbus device may *NOT* be hotplugged */

MODULE_ALIAS("platform:gpio-vbus");

static struct platform_driver gpio_vbus_driver = {
	.driver = {
		.name  = "gpio-vbus",
		.owner = THIS_MODULE,
#ifdef CONFIG_PM
		.pm = &gpio_vbus_dev_pm_ops,
#endif
	},
	.remove  = __exit_p(gpio_vbus_remove),
};

static int __init gpio_vbus_init(void)
{
	return platform_driver_probe(&gpio_vbus_driver, gpio_vbus_probe);
}
module_init(gpio_vbus_init);

static void __exit gpio_vbus_exit(void)
{
	platform_driver_unregister(&gpio_vbus_driver);
}
module_exit(gpio_vbus_exit);

MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
MODULE_AUTHOR("Philipp Zabel");
MODULE_LICENSE("GPL");