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Linux/drivers/usb/phy/phy-gpio-vbus-usb.c

  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 

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