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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * gpio-vbus.c - simple GPIO VBUS sensing driver for B peripheral devices
4 *
5 * Copyright (c) 2008 Philipp Zabel <philipp.zabel@gmail.com>
6 */
7
8#include <linux/kernel.h>
9#include <linux/platform_device.h>
10#include <linux/gpio/consumer.h>
11#include <linux/module.h>
12#include <linux/slab.h>
13#include <linux/interrupt.h>
14#include <linux/usb.h>
15#include <linux/workqueue.h>
16
17#include <linux/regulator/consumer.h>
18
19#include <linux/usb/gadget.h>
20#include <linux/usb/otg.h>
21
22
23/*
24 * A simple GPIO VBUS sensing driver for B peripheral only devices
25 * with internal transceivers. It can control a D+ pullup GPIO and
26 * a regulator to limit the current drawn from VBUS.
27 *
28 * Needs to be loaded before the UDC driver that will use it.
29 */
30struct gpio_vbus_data {
31 struct gpio_desc *vbus_gpiod;
32 struct gpio_desc *pullup_gpiod;
33 struct usb_phy phy;
34 struct device *dev;
35 struct regulator *vbus_draw;
36 int vbus_draw_enabled;
37 unsigned mA;
38 struct delayed_work work;
39 int vbus;
40 int irq;
41};
42
43
44/*
45 * This driver relies on "both edges" triggering. VBUS has 100 msec to
46 * stabilize, so the peripheral controller driver may need to cope with
47 * some bouncing due to current surges (e.g. charging local capacitance)
48 * and contact chatter.
49 *
50 * REVISIT in desperate straits, toggling between rising and falling
51 * edges might be workable.
52 */
53#define VBUS_IRQ_FLAGS \
54 (IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
55
56
57/* interface to regulator framework */
58static void set_vbus_draw(struct gpio_vbus_data *gpio_vbus, unsigned mA)
59{
60 struct regulator *vbus_draw = gpio_vbus->vbus_draw;
61 int enabled;
62 int ret;
63
64 if (!vbus_draw)
65 return;
66
67 enabled = gpio_vbus->vbus_draw_enabled;
68 if (mA) {
69 regulator_set_current_limit(vbus_draw, 0, 1000 * mA);
70 if (!enabled) {
71 ret = regulator_enable(vbus_draw);
72 if (ret < 0)
73 return;
74 gpio_vbus->vbus_draw_enabled = 1;
75 }
76 } else {
77 if (enabled) {
78 ret = regulator_disable(vbus_draw);
79 if (ret < 0)
80 return;
81 gpio_vbus->vbus_draw_enabled = 0;
82 }
83 }
84 gpio_vbus->mA = mA;
85}
86
87static int is_vbus_powered(struct gpio_vbus_data *gpio_vbus)
88{
89 return gpiod_get_value(gpio_vbus->vbus_gpiod);
90}
91
92static void gpio_vbus_work(struct work_struct *work)
93{
94 struct gpio_vbus_data *gpio_vbus =
95 container_of(work, struct gpio_vbus_data, work.work);
96 int status, vbus;
97
98 if (!gpio_vbus->phy.otg->gadget)
99 return;
100
101 vbus = is_vbus_powered(gpio_vbus);
102 if ((vbus ^ gpio_vbus->vbus) == 0)
103 return;
104 gpio_vbus->vbus = vbus;
105
106 /* Peripheral controllers which manage the pullup themselves won't have
107 * a pullup GPIO configured here. If it's configured here, we'll do
108 * what isp1301_omap::b_peripheral() does and enable the pullup here...
109 * although that may complicate usb_gadget_{,dis}connect() support.
110 */
111
112 if (vbus) {
113 status = USB_EVENT_VBUS;
114 gpio_vbus->phy.otg->state = OTG_STATE_B_PERIPHERAL;
115 gpio_vbus->phy.last_event = status;
116 usb_gadget_vbus_connect(gpio_vbus->phy.otg->gadget);
117
118 /* drawing a "unit load" is *always* OK, except for OTG */
119 set_vbus_draw(gpio_vbus, 100);
120
121 /* optionally enable D+ pullup */
122 if (gpio_vbus->pullup_gpiod)
123 gpiod_set_value(gpio_vbus->pullup_gpiod, 1);
124
125 atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
126 status, gpio_vbus->phy.otg->gadget);
127 usb_phy_set_event(&gpio_vbus->phy, USB_EVENT_ENUMERATED);
128 } else {
129 /* optionally disable D+ pullup */
130 if (gpio_vbus->pullup_gpiod)
131 gpiod_set_value(gpio_vbus->pullup_gpiod, 0);
132
133 set_vbus_draw(gpio_vbus, 0);
134
135 usb_gadget_vbus_disconnect(gpio_vbus->phy.otg->gadget);
136 status = USB_EVENT_NONE;
137 gpio_vbus->phy.otg->state = OTG_STATE_B_IDLE;
138 gpio_vbus->phy.last_event = status;
139
140 atomic_notifier_call_chain(&gpio_vbus->phy.notifier,
141 status, gpio_vbus->phy.otg->gadget);
142 usb_phy_set_event(&gpio_vbus->phy, USB_EVENT_NONE);
143 }
144}
145
146/* VBUS change IRQ handler */
147static irqreturn_t gpio_vbus_irq(int irq, void *data)
148{
149 struct platform_device *pdev = data;
150 struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
151 struct usb_otg *otg = gpio_vbus->phy.otg;
152
153 dev_dbg(&pdev->dev, "VBUS %s (gadget: %s)\n",
154 is_vbus_powered(gpio_vbus) ? "supplied" : "inactive",
155 otg->gadget ? otg->gadget->name : "none");
156
157 if (otg->gadget)
158 schedule_delayed_work(&gpio_vbus->work, msecs_to_jiffies(100));
159
160 return IRQ_HANDLED;
161}
162
163/* OTG transceiver interface */
164
165/* bind/unbind the peripheral controller */
166static int gpio_vbus_set_peripheral(struct usb_otg *otg,
167 struct usb_gadget *gadget)
168{
169 struct gpio_vbus_data *gpio_vbus;
170 struct platform_device *pdev;
171
172 gpio_vbus = container_of(otg->usb_phy, struct gpio_vbus_data, phy);
173 pdev = to_platform_device(gpio_vbus->dev);
174
175 if (!gadget) {
176 dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
177 otg->gadget->name);
178
179 /* optionally disable D+ pullup */
180 if (gpio_vbus->pullup_gpiod)
181 gpiod_set_value(gpio_vbus->pullup_gpiod, 0);
182
183 set_vbus_draw(gpio_vbus, 0);
184
185 usb_gadget_vbus_disconnect(otg->gadget);
186 otg->state = OTG_STATE_UNDEFINED;
187
188 otg->gadget = NULL;
189 return 0;
190 }
191
192 otg->gadget = gadget;
193 dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
194
195 /* initialize connection state */
196 gpio_vbus->vbus = 0; /* start with disconnected */
197 gpio_vbus_irq(gpio_vbus->irq, pdev);
198 return 0;
199}
200
201/* effective for B devices, ignored for A-peripheral */
202static int gpio_vbus_set_power(struct usb_phy *phy, unsigned mA)
203{
204 struct gpio_vbus_data *gpio_vbus;
205
206 gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
207
208 if (phy->otg->state == OTG_STATE_B_PERIPHERAL)
209 set_vbus_draw(gpio_vbus, mA);
210 return 0;
211}
212
213/* for non-OTG B devices: set/clear transceiver suspend mode */
214static int gpio_vbus_set_suspend(struct usb_phy *phy, int suspend)
215{
216 struct gpio_vbus_data *gpio_vbus;
217
218 gpio_vbus = container_of(phy, struct gpio_vbus_data, phy);
219
220 /* draw max 0 mA from vbus in suspend mode; or the previously
221 * recorded amount of current if not suspended
222 *
223 * NOTE: high powered configs (mA > 100) may draw up to 2.5 mA
224 * if they're wake-enabled ... we don't handle that yet.
225 */
226 return gpio_vbus_set_power(phy, suspend ? 0 : gpio_vbus->mA);
227}
228
229/* platform driver interface */
230
231static int gpio_vbus_probe(struct platform_device *pdev)
232{
233 struct gpio_vbus_data *gpio_vbus;
234 struct resource *res;
235 struct device *dev = &pdev->dev;
236 int err, irq;
237 unsigned long irqflags;
238
239 gpio_vbus = devm_kzalloc(&pdev->dev, sizeof(struct gpio_vbus_data),
240 GFP_KERNEL);
241 if (!gpio_vbus)
242 return -ENOMEM;
243
244 gpio_vbus->phy.otg = devm_kzalloc(&pdev->dev, sizeof(struct usb_otg),
245 GFP_KERNEL);
246 if (!gpio_vbus->phy.otg)
247 return -ENOMEM;
248
249 platform_set_drvdata(pdev, gpio_vbus);
250 gpio_vbus->dev = &pdev->dev;
251 gpio_vbus->phy.label = "gpio-vbus";
252 gpio_vbus->phy.dev = gpio_vbus->dev;
253 gpio_vbus->phy.set_power = gpio_vbus_set_power;
254 gpio_vbus->phy.set_suspend = gpio_vbus_set_suspend;
255
256 gpio_vbus->phy.otg->state = OTG_STATE_UNDEFINED;
257 gpio_vbus->phy.otg->usb_phy = &gpio_vbus->phy;
258 gpio_vbus->phy.otg->set_peripheral = gpio_vbus_set_peripheral;
259
260 /* Look up the VBUS sensing GPIO */
261 gpio_vbus->vbus_gpiod = devm_gpiod_get(dev, "vbus", GPIOD_IN);
262 if (IS_ERR(gpio_vbus->vbus_gpiod)) {
263 err = PTR_ERR(gpio_vbus->vbus_gpiod);
264 dev_err(&pdev->dev, "can't request vbus gpio, err: %d\n", err);
265 return err;
266 }
267 gpiod_set_consumer_name(gpio_vbus->vbus_gpiod, "vbus_detect");
268
269 res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
270 if (res) {
271 irq = res->start;
272 irqflags = (res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
273 } else {
274 irq = gpiod_to_irq(gpio_vbus->vbus_gpiod);
275 irqflags = VBUS_IRQ_FLAGS;
276 }
277
278 gpio_vbus->irq = irq;
279
280 /*
281 * The VBUS sensing GPIO should have a pulldown, which will normally be
282 * part of a resistor ladder turning a 4.0V-5.25V level on VBUS into a
283 * value the GPIO detects as active. Some systems will use comparators.
284 * Get the optional D+ or D- pullup GPIO. If the data line pullup is
285 * in use, initialize it to "not pulling up"
286 */
287 gpio_vbus->pullup_gpiod = devm_gpiod_get_optional(dev, "pullup",
288 GPIOD_OUT_LOW);
289 if (IS_ERR(gpio_vbus->pullup_gpiod)) {
290 err = PTR_ERR(gpio_vbus->pullup_gpiod);
291 dev_err(&pdev->dev, "can't request pullup gpio, err: %d\n",
292 err);
293 return err;
294 }
295 if (gpio_vbus->pullup_gpiod)
296 gpiod_set_consumer_name(gpio_vbus->pullup_gpiod, "udc_pullup");
297
298 err = devm_request_irq(&pdev->dev, irq, gpio_vbus_irq, irqflags,
299 "vbus_detect", pdev);
300 if (err) {
301 dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
302 irq, err);
303 return err;
304 }
305
306 INIT_DELAYED_WORK(&gpio_vbus->work, gpio_vbus_work);
307
308 gpio_vbus->vbus_draw = devm_regulator_get(&pdev->dev, "vbus_draw");
309 if (IS_ERR(gpio_vbus->vbus_draw)) {
310 dev_dbg(&pdev->dev, "can't get vbus_draw regulator, err: %ld\n",
311 PTR_ERR(gpio_vbus->vbus_draw));
312 gpio_vbus->vbus_draw = NULL;
313 }
314
315 /* only active when a gadget is registered */
316 err = usb_add_phy(&gpio_vbus->phy, USB_PHY_TYPE_USB2);
317 if (err) {
318 dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
319 err);
320 return err;
321 }
322
323 /* TODO: wakeup could be enabled here with device_init_wakeup(dev, 1) */
324
325 return 0;
326}
327
328static void gpio_vbus_remove(struct platform_device *pdev)
329{
330 struct gpio_vbus_data *gpio_vbus = platform_get_drvdata(pdev);
331
332 device_init_wakeup(&pdev->dev, 0);
333 cancel_delayed_work_sync(&gpio_vbus->work);
334
335 usb_remove_phy(&gpio_vbus->phy);
336}
337
338#ifdef CONFIG_PM
339static int gpio_vbus_pm_suspend(struct device *dev)
340{
341 struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
342
343 if (device_may_wakeup(dev))
344 enable_irq_wake(gpio_vbus->irq);
345
346 return 0;
347}
348
349static int gpio_vbus_pm_resume(struct device *dev)
350{
351 struct gpio_vbus_data *gpio_vbus = dev_get_drvdata(dev);
352
353 if (device_may_wakeup(dev))
354 disable_irq_wake(gpio_vbus->irq);
355
356 return 0;
357}
358
359static const struct dev_pm_ops gpio_vbus_dev_pm_ops = {
360 .suspend = gpio_vbus_pm_suspend,
361 .resume = gpio_vbus_pm_resume,
362};
363#endif
364
365MODULE_ALIAS("platform:gpio-vbus");
366
367/*
368 * NOTE: this driver matches against "gpio-usb-b-connector" for
369 * devices that do NOT support role switch.
370 */
371static const struct of_device_id gpio_vbus_of_match[] = {
372 {
373 .compatible = "gpio-usb-b-connector",
374 },
375 {},
376};
377
378static struct platform_driver gpio_vbus_driver = {
379 .driver = {
380 .name = "gpio-vbus",
381#ifdef CONFIG_PM
382 .pm = &gpio_vbus_dev_pm_ops,
383#endif
384 .of_match_table = gpio_vbus_of_match,
385 },
386 .probe = gpio_vbus_probe,
387 .remove_new = gpio_vbus_remove,
388};
389
390module_platform_driver(gpio_vbus_driver);
391
392MODULE_DESCRIPTION("simple GPIO controlled OTG transceiver driver");
393MODULE_AUTHOR("Philipp Zabel");
394MODULE_LICENSE("GPL");