xref: /linux/drivers/usb/phy/phy-gpio-vbus-usb.c (revision e0bf6c5ca2d3281f231c5f0c9bf145e9513644de) 
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  */
34 struct 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 */
60 static 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 
89 static 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 
100 static 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 = dev_get_platdata(gpio_vbus->dev);
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.otg->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 		usb_phy_set_event(&gpio_vbus->phy, USB_EVENT_ENUMERATED);
138 	} else {
139 		/* optionally disable D+ pullup */
140 		if (gpio_is_valid(gpio))
141 			gpio_set_value(gpio, pdata->gpio_pullup_inverted);
142 
143 		set_vbus_draw(gpio_vbus, 0);
144 
145 		usb_gadget_vbus_disconnect(gpio_vbus->phy.otg->gadget);
146 		status = USB_EVENT_NONE;
147 		gpio_vbus->phy.otg->state = OTG_STATE_B_IDLE;
148 		gpio_vbus->phy.last_event = status;
149 
150 		atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
151 					   status, gpio_vbus->phy.otg->gadget);
152 		usb_phy_set_event(&gpio_vbus->phy, USB_EVENT_NONE);
153 	}
154 }
155 
156 /* VBUS change IRQ handler */
157 static irqreturn_t gpio_vbus_irq(int irq, void *data)
158 {
159 	struct platform_device *pdev = data;
160 	struct gpio_vbus_mach_info *pdata = dev_get_platdata(&pdev->dev);
161 	struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
162 	struct usb_otg *otg = gpio_vbus->phy.otg;
163 
164 	dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
165 		is_vbus_powered(pdata) ? "supplied" : "inactive",
166 		otg->gadget ? otg->gadget->name : "none");
167 
168 	if (otg->gadget)
169 		schedule_delayed_work(&gpio_vbus->work, msecs_to_jiffies(100));
170 
171 	return IRQ_HANDLED;
172 }
173 
174 /* OTG transceiver interface */
175 
176 /* bind/unbind the peripheral controller */
177 static int gpio_vbus_set_peripheral(struct usb_otg *otg,
178 					struct usb_gadget *gadget)
179 {
180 	struct gpio_vbus_data *gpio_vbus;
181 	struct gpio_vbus_mach_info *pdata;
182 	struct platform_device *pdev;
183 	int gpio;
184 
185 	gpio_vbus = container_of(otg->usb_phy, struct gpio_vbus_data, phy);
186 	pdev = to_platform_device(gpio_vbus->dev);
187 	pdata = dev_get_platdata(gpio_vbus->dev);
188 	gpio = pdata->gpio_pullup;
189 
190 	if (!gadget) {
191 		dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
192 			otg->gadget->name);
193 
194 		/* optionally disable D+ pullup */
195 		if (gpio_is_valid(gpio))
196 			gpio_set_value(gpio, pdata->gpio_pullup_inverted);
197 
198 		set_vbus_draw(gpio_vbus, 0);
199 
200 		usb_gadget_vbus_disconnect(otg->gadget);
201 		otg->state = OTG_STATE_UNDEFINED;
202 
203 		otg->gadget = NULL;
204 		return 0;
205 	}
206 
207 	otg->gadget = gadget;
208 	dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
209 
210 	/* initialize connection state */
211 	gpio_vbus->vbus = 0; /* start with disconnected */
212 	gpio_vbus_irq(gpio_vbus->irq, pdev);
213 	return 0;
214 }
215 
216 /* effective for B devices, ignored for A-peripheral */
217 static int gpio_vbus_set_power(struct usb_phy *phy, unsigned mA)
218 {
219 	struct gpio_vbus_data *gpio_vbus;
220 
221 	gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
222 
223 	if (phy->otg->state == OTG_STATE_B_PERIPHERAL)
224 		set_vbus_draw(gpio_vbus, mA);
225 	return 0;
226 }
227 
228 /* for non-OTG B devices: set/clear transceiver suspend mode */
229 static int gpio_vbus_set_suspend(struct usb_phy *phy, int suspend)
230 {
231 	struct gpio_vbus_data *gpio_vbus;
232 
233 	gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
234 
235 	/* draw max 0 mA from vbus in suspend mode; or the previously
236 	 * recorded amount of current if not suspended
237 	 *
238 	 * NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
239 	 * if they're wake-enabled ... we don't handle that yet.
240 	 */
241 	return gpio_vbus_set_power(phy, suspend ? 0 : gpio_vbus->mA);
242 }
243 
244 /* platform driver interface */
245 
246 static int gpio_vbus_probe(struct platform_device *pdev)
247 {
248 	struct gpio_vbus_mach_info *pdata = dev_get_platdata(&pdev->dev);
249 	struct gpio_vbus_data *gpio_vbus;
250 	struct resource *res;
251 	int err, gpio, irq;
252 	unsigned long irqflags;
253 
254 	if (!pdata || !gpio_is_valid(pdata->gpio_vbus))
255 		return -EINVAL;
256 	gpio = pdata->gpio_vbus;
257 
258 	gpio_vbus = devm_kzalloc(&pdev->dev, sizeof(struct gpio_vbus_data),
259 				 GFP_KERNEL);
260 	if (!gpio_vbus)
261 		return -ENOMEM;
262 
263 	gpio_vbus->phy.otg = devm_kzalloc(&pdev->dev, sizeof(struct usb_otg),
264 					  GFP_KERNEL);
265 	if (!gpio_vbus->phy.otg)
266 		return -ENOMEM;
267 
268 	platform_set_drvdata(pdev, gpio_vbus);
269 	gpio_vbus->dev = &pdev->dev;
270 	gpio_vbus->phy.label = "gpio-vbus";
271 	gpio_vbus->phy.dev = gpio_vbus->dev;
272 	gpio_vbus->phy.set_power = gpio_vbus_set_power;
273 	gpio_vbus->phy.set_suspend = gpio_vbus_set_suspend;
274 
275 	gpio_vbus->phy.otg->state = OTG_STATE_UNDEFINED;
276 	gpio_vbus->phy.otg->usb_phy = &gpio_vbus->phy;
277 	gpio_vbus->phy.otg->set_peripheral = gpio_vbus_set_peripheral;
278 
279 	err = devm_gpio_request(&pdev->dev, gpio, "vbus_detect");
280 	if (err) {
281 		dev_err(&pdev->dev, "can't request vbus gpio %d, err: %d\n",
282 			gpio, err);
283 		return err;
284 	}
285 	gpio_direction_input(gpio);
286 
287 	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
288 	if (res) {
289 		irq = res->start;
290 		irqflags = (res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
291 	} else {
292 		irq = gpio_to_irq(gpio);
293 		irqflags = VBUS_IRQ_FLAGS;
294 	}
295 
296 	gpio_vbus->irq = irq;
297 
298 	/* if data line pullup is in use, initialize it to "not pulling up" */
299 	gpio = pdata->gpio_pullup;
300 	if (gpio_is_valid(gpio)) {
301 		err = devm_gpio_request(&pdev->dev, gpio, "udc_pullup");
302 		if (err) {
303 			dev_err(&pdev->dev,
304 				"can't request pullup gpio %d, err: %d\n",
305 				gpio, err);
306 			return err;
307 		}
308 		gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
309 	}
310 
311 	err = devm_request_irq(&pdev->dev, irq, gpio_vbus_irq, irqflags,
312 			       "vbus_detect", pdev);
313 	if (err) {
314 		dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
315 			irq, err);
316 		return err;
317 	}
318 
319 	INIT_DELAYED_WORK(&gpio_vbus->work, gpio_vbus_work);
320 
321 	gpio_vbus->vbus_draw = devm_regulator_get(&pdev->dev, "vbus_draw");
322 	if (IS_ERR(gpio_vbus->vbus_draw)) {
323 		dev_dbg(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
324 			PTR_ERR(gpio_vbus->vbus_draw));
325 		gpio_vbus->vbus_draw = NULL;
326 	}
327 
328 	/* only active when a gadget is registered */
329 	err = usb_add_phy(&gpio_vbus->phy, USB_PHY_TYPE_USB2);
330 	if (err) {
331 		dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
332 			err);
333 		return err;
334 	}
335 
336 	device_init_wakeup(&pdev->dev, pdata->wakeup);
337 
338 	return 0;
339 }
340 
341 static int gpio_vbus_remove(struct platform_device *pdev)
342 {
343 	struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
344 
345 	device_init_wakeup(&pdev->dev, 0);
346 	cancel_delayed_work_sync(&gpio_vbus->work);
347 
348 	usb_remove_phy(&gpio_vbus->phy);
349 
350 	return 0;
351 }
352 
353 #ifdef CONFIG_PM
354 static int gpio_vbus_pm_suspend(struct device *dev)
355 {
356 	struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
357 
358 	if (device_may_wakeup(dev))
359 		enable_irq_wake(gpio_vbus->irq);
360 
361 	return 0;
362 }
363 
364 static int gpio_vbus_pm_resume(struct device *dev)
365 {
366 	struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
367 
368 	if (device_may_wakeup(dev))
369 		disable_irq_wake(gpio_vbus->irq);
370 
371 	return 0;
372 }
373 
374 static const struct dev_pm_ops gpio_vbus_dev_pm_ops = {
375 	.suspend	= gpio_vbus_pm_suspend,
376 	.resume		= gpio_vbus_pm_resume,
377 };
378 #endif
379 
380 MODULE_ALIAS("platform:gpio-vbus");
381 
382 static struct platform_driver gpio_vbus_driver = {
383 	.driver = {
384 		.name  = "gpio-vbus",
385 #ifdef CONFIG_PM
386 		.pm = &gpio_vbus_dev_pm_ops,
387 #endif
388 	},
389 	.probe		= gpio_vbus_probe,
390 	.remove		= gpio_vbus_remove,
391 };
392 
393 module_platform_driver(gpio_vbus_driver);
394 
395 MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
396 MODULE_AUTHOR("Philipp Zabel");
397 MODULE_LICENSE("GPL");
398