phy-gpio-vbus-usb.c revision e8d891fb7b8fe4ee7311820594323d46dbc31d45 
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	int ret;
65
66	if (!vbus_draw)
67		return;
68
69	enabled = gpio_vbus->vbus_draw_enabled;
70	if (mA) {
71		regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
72		if (!enabled) {
73			ret = regulator_enable(vbus_draw);
74			if (ret < 0)
75				return;
76			gpio_vbus->vbus_draw_enabled = 1;
77		}
78	} else {
79		if (enabled) {
80			ret = regulator_disable(vbus_draw);
81			if (ret < 0)
82				return;
83			gpio_vbus->vbus_draw_enabled = 0;
84		}
85	}
86	gpio_vbus->mA = mA;
87}
88
89static int is_vbus_powered(struct gpio_vbus_mach_info *pdata)
90{
91	int vbus;
92
93	vbus = gpio_get_value(pdata->gpio_vbus);
94	if (pdata->gpio_vbus_inverted)
95		vbus = !vbus;
96
97	return vbus;
98}
99
100static void gpio_vbus_work(struct work_struct *work)
101{
102	struct gpio_vbus_data *gpio_vbus =
103		container_of(work, struct gpio_vbus_data, work.work);
104	struct gpio_vbus_mach_info *pdata = gpio_vbus->dev->platform_data;
105	int gpio, status, vbus;
106
107	if (!gpio_vbus->phy.otg->gadget)
108		return;
109
110	vbus = is_vbus_powered(pdata);
111	if ((vbus ^ gpio_vbus->vbus) == 0)
112		return;
113	gpio_vbus->vbus = vbus;
114
115	/* Peripheral controllers which manage the pullup themselves won't have
116	 * gpio_pullup configured here.  If it's configured here, we'll do what
117	 * isp1301_omap::b_peripheral() does and enable the pullup here... although
118	 * that may complicate usb_gadget_{,dis}connect() support.
119	 */
120	gpio = pdata->gpio_pullup;
121
122	if (vbus) {
123		status = USB_EVENT_VBUS;
124		gpio_vbus->phy.state = OTG_STATE_B_PERIPHERAL;
125		gpio_vbus->phy.last_event = status;
126		usb_gadget_vbus_connect(gpio_vbus->phy.otg->gadget);
127
128		/* drawing a "unit load" is *always* OK, except for OTG */
129		set_vbus_draw(gpio_vbus, 100);
130
131		/* optionally enable D+ pullup */
132		if (gpio_is_valid(gpio))
133			gpio_set_value(gpio, !pdata->gpio_pullup_inverted);
134
135		atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
136					   status, gpio_vbus->phy.otg->gadget);
137	} else {
138		/* optionally disable D+ pullup */
139		if (gpio_is_valid(gpio))
140			gpio_set_value(gpio, pdata->gpio_pullup_inverted);
141
142		set_vbus_draw(gpio_vbus, 0);
143
144		usb_gadget_vbus_disconnect(gpio_vbus->phy.otg->gadget);
145		status = USB_EVENT_NONE;
146		gpio_vbus->phy.state = OTG_STATE_B_IDLE;
147		gpio_vbus->phy.last_event = status;
148
149		atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
150					   status, gpio_vbus->phy.otg->gadget);
151	}
152}
153
154/* VBUS change IRQ handler */
155static irqreturn_t gpio_vbus_irq(int irq, void *data)
156{
157	struct platform_device *pdev = data;
158	struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
159	struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
160	struct usb_otg *otg = gpio_vbus->phy.otg;
161
162	dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
163		is_vbus_powered(pdata) ? "supplied" : "inactive",
164		otg->gadget ? otg->gadget->name : "none");
165
166	if (otg->gadget)
167		schedule_delayed_work(&gpio_vbus->work, msecs_to_jiffies(100));
168
169	return IRQ_HANDLED;
170}
171
172/* OTG transceiver interface */
173
174/* bind/unbind the peripheral controller */
175static int gpio_vbus_set_peripheral(struct usb_otg *otg,
176					struct usb_gadget *gadget)
177{
178	struct gpio_vbus_data *gpio_vbus;
179	struct gpio_vbus_mach_info *pdata;
180	struct platform_device *pdev;
181	int gpio;
182
183	gpio_vbus = container_of(otg->phy, struct gpio_vbus_data, phy);
184	pdev = to_platform_device(gpio_vbus->dev);
185	pdata = gpio_vbus->dev->platform_data;
186	gpio = pdata->gpio_pullup;
187
188	if (!gadget) {
189		dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
190			otg->gadget->name);
191
192		/* optionally disable D+ pullup */
193		if (gpio_is_valid(gpio))
194			gpio_set_value(gpio, pdata->gpio_pullup_inverted);
195
196		set_vbus_draw(gpio_vbus, 0);
197
198		usb_gadget_vbus_disconnect(otg->gadget);
199		otg->phy->state = OTG_STATE_UNDEFINED;
200
201		otg->gadget = NULL;
202		return 0;
203	}
204
205	otg->gadget = gadget;
206	dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
207
208	/* initialize connection state */
209	gpio_vbus->vbus = 0; /* start with disconnected */
210	gpio_vbus_irq(gpio_vbus->irq, pdev);
211	return 0;
212}
213
214/* effective for B devices, ignored for A-peripheral */
215static int gpio_vbus_set_power(struct usb_phy *phy, unsigned mA)
216{
217	struct gpio_vbus_data *gpio_vbus;
218
219	gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
220
221	if (phy->state == OTG_STATE_B_PERIPHERAL)
222		set_vbus_draw(gpio_vbus, mA);
223	return 0;
224}
225
226/* for non-OTG B devices: set/clear transceiver suspend mode */
227static int gpio_vbus_set_suspend(struct usb_phy *phy, int suspend)
228{
229	struct gpio_vbus_data *gpio_vbus;
230
231	gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
232
233	/* draw max 0 mA from vbus in suspend mode; or the previously
234	 * recorded amount of current if not suspended
235	 *
236	 * NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
237	 * if they're wake-enabled ... we don't handle that yet.
238	 */
239	return gpio_vbus_set_power(phy, suspend ? 0 : gpio_vbus->mA);
240}
241
242/* platform driver interface */
243
244static int __init gpio_vbus_probe(struct platform_device *pdev)
245{
246	struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
247	struct gpio_vbus_data *gpio_vbus;
248	struct resource *res;
249	int err, gpio, irq;
250	unsigned long irqflags;
251
252	if (!pdata || !gpio_is_valid(pdata->gpio_vbus))
253		return -EINVAL;
254	gpio = pdata->gpio_vbus;
255
256	gpio_vbus = kzalloc(sizeof(struct gpio_vbus_data), GFP_KERNEL);
257	if (!gpio_vbus)
258		return -ENOMEM;
259
260	gpio_vbus->phy.otg = kzalloc(sizeof(struct usb_otg), GFP_KERNEL);
261	if (!gpio_vbus->phy.otg) {
262		kfree(gpio_vbus);
263		return -ENOMEM;
264	}
265
266	platform_set_drvdata(pdev, gpio_vbus);
267	gpio_vbus->dev = &pdev->dev;
268	gpio_vbus->phy.label = "gpio-vbus";
269	gpio_vbus->phy.set_power = gpio_vbus_set_power;
270	gpio_vbus->phy.set_suspend = gpio_vbus_set_suspend;
271	gpio_vbus->phy.state = OTG_STATE_UNDEFINED;
272
273	gpio_vbus->phy.otg->phy = &gpio_vbus->phy;
274	gpio_vbus->phy.otg->set_peripheral = gpio_vbus_set_peripheral;
275
276	err = gpio_request(gpio, "vbus_detect");
277	if (err) {
278		dev_err(&pdev->dev, "can't request vbus gpio %d, err: %d\n",
279			gpio, err);
280		goto err_gpio;
281	}
282	gpio_direction_input(gpio);
283
284	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
285	if (res) {
286		irq = res->start;
287		irqflags = (res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
288	} else {
289		irq = gpio_to_irq(gpio);
290		irqflags = VBUS_IRQ_FLAGS;
291	}
292
293	gpio_vbus->irq = irq;
294
295	/* if data line pullup is in use, initialize it to "not pulling up" */
296	gpio = pdata->gpio_pullup;
297	if (gpio_is_valid(gpio)) {
298		err = gpio_request(gpio, "udc_pullup");
299		if (err) {
300			dev_err(&pdev->dev,
301				"can't request pullup gpio %d, err: %d\n",
302				gpio, err);
303			gpio_free(pdata->gpio_vbus);
304			goto err_gpio;
305		}
306		gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
307	}
308
309	err = request_irq(irq, gpio_vbus_irq, irqflags, "vbus_detect", pdev);
310	if (err) {
311		dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
312			irq, err);
313		goto err_irq;
314	}
315
316	ATOMIC_INIT_NOTIFIER_HEAD(&gpio_vbus->phy.notifier);
317
318	INIT_DELAYED_WORK(&gpio_vbus->work, gpio_vbus_work);
319
320	gpio_vbus->vbus_draw = regulator_get(&pdev->dev, "vbus_draw");
321	if (IS_ERR(gpio_vbus->vbus_draw)) {
322		dev_dbg(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
323			PTR_ERR(gpio_vbus->vbus_draw));
324		gpio_vbus->vbus_draw = NULL;
325	}
326
327	/* only active when a gadget is registered */
328	err = usb_add_phy(&gpio_vbus->phy, USB_PHY_TYPE_USB2);
329	if (err) {
330		dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
331			err);
332		goto err_otg;
333	}
334
335	device_init_wakeup(&pdev->dev, pdata->wakeup);
336
337	return 0;
338err_otg:
339	regulator_put(gpio_vbus->vbus_draw);
340	free_irq(irq, pdev);
341err_irq:
342	if (gpio_is_valid(pdata->gpio_pullup))
343		gpio_free(pdata->gpio_pullup);
344	gpio_free(pdata->gpio_vbus);
345err_gpio:
346	platform_set_drvdata(pdev, NULL);
347	kfree(gpio_vbus->phy.otg);
348	kfree(gpio_vbus);
349	return err;
350}
351
352static int __exit gpio_vbus_remove(struct platform_device *pdev)
353{
354	struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
355	struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
356	int gpio = pdata->gpio_vbus;
357
358	device_init_wakeup(&pdev->dev, 0);
359	cancel_delayed_work_sync(&gpio_vbus->work);
360	regulator_put(gpio_vbus->vbus_draw);
361
362	usb_remove_phy(&gpio_vbus->phy);
363
364	free_irq(gpio_vbus->irq, pdev);
365	if (gpio_is_valid(pdata->gpio_pullup))
366		gpio_free(pdata->gpio_pullup);
367	gpio_free(gpio);
368	platform_set_drvdata(pdev, NULL);
369	kfree(gpio_vbus->phy.otg);
370	kfree(gpio_vbus);
371
372	return 0;
373}
374
375#ifdef CONFIG_PM
376static int gpio_vbus_pm_suspend(struct device *dev)
377{
378	struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
379
380	if (device_may_wakeup(dev))
381		enable_irq_wake(gpio_vbus->irq);
382
383	return 0;
384}
385
386static int gpio_vbus_pm_resume(struct device *dev)
387{
388	struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
389
390	if (device_may_wakeup(dev))
391		disable_irq_wake(gpio_vbus->irq);
392
393	return 0;
394}
395
396static const struct dev_pm_ops gpio_vbus_dev_pm_ops = {
397	.suspend	= gpio_vbus_pm_suspend,
398	.resume		= gpio_vbus_pm_resume,
399};
400#endif
401
402/* NOTE:  the gpio-vbus device may *NOT* be hotplugged */
403
404MODULE_ALIAS("platform:gpio-vbus");
405
406static struct platform_driver gpio_vbus_driver = {
407	.driver = {
408		.name  = "gpio-vbus",
409		.owner = THIS_MODULE,
410#ifdef CONFIG_PM
411		.pm = &gpio_vbus_dev_pm_ops,
412#endif
413	},
414	.remove  = __exit_p(gpio_vbus_remove),
415};
416
417module_platform_driver_probe(gpio_vbus_driver, gpio_vbus_probe);
418
419MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
420MODULE_AUTHOR("Philipp Zabel");
421MODULE_LICENSE("GPL");
422