1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * USB GPIO Based Connection Detection Driver
4  *
5  * Copyright (C) 2019 MediaTek Inc.
6  *
7  * Author: Chunfeng Yun <chunfeng.yun@mediatek.com>
8  *
9  * Some code borrowed from drivers/extcon/extcon-usb-gpio.c
10  */
11 
12 #include <linux/device.h>
13 #include <linux/gpio/consumer.h>
14 #include <linux/interrupt.h>
15 #include <linux/irq.h>
16 #include <linux/module.h>
17 #include <linux/of.h>
18 #include <linux/pinctrl/consumer.h>
19 #include <linux/platform_device.h>
20 #include <linux/power_supply.h>
21 #include <linux/regulator/consumer.h>
22 #include <linux/usb/role.h>
23 
24 #define USB_GPIO_DEB_MS		20	/* ms */
25 #define USB_GPIO_DEB_US		((USB_GPIO_DEB_MS) * 1000)	/* us */
26 
27 #define USB_CONN_IRQF	\
28 	(IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT)
29 
30 struct usb_conn_info {
31 	struct device *dev;
32 	struct usb_role_switch *role_sw;
33 	enum usb_role last_role;
34 	struct regulator *vbus;
35 	struct delayed_work dw_det;
36 	unsigned long debounce_jiffies;
37 
38 	struct gpio_desc *id_gpiod;
39 	struct gpio_desc *vbus_gpiod;
40 	int id_irq;
41 	int vbus_irq;
42 
43 	struct power_supply_desc desc;
44 	struct power_supply *charger;
45 };
46 
47 /*
48  * "DEVICE" = VBUS and "HOST" = !ID, so we have:
49  * Both "DEVICE" and "HOST" can't be set as active at the same time
50  * so if "HOST" is active (i.e. ID is 0)  we keep "DEVICE" inactive
51  * even if VBUS is on.
52  *
53  *  Role          |   ID  |  VBUS
54  * ------------------------------------
55  *  [1] DEVICE    |   H   |   H
56  *  [2] NONE      |   H   |   L
57  *  [3] HOST      |   L   |   H
58  *  [4] HOST      |   L   |   L
59  *
60  * In case we have only one of these signals:
61  * - VBUS only - we want to distinguish between [1] and [2], so ID is always 1
62  * - ID only - we want to distinguish between [1] and [4], so VBUS = ID
63  */
64 static void usb_conn_detect_cable(struct work_struct *work)
65 {
66 	struct usb_conn_info *info;
67 	enum usb_role role;
68 	int id, vbus, ret;
69 
70 	info = container_of(to_delayed_work(work),
71 			    struct usb_conn_info, dw_det);
72 
73 	/* check ID and VBUS */
74 	id = info->id_gpiod ?
75 		gpiod_get_value_cansleep(info->id_gpiod) : 1;
76 	vbus = info->vbus_gpiod ?
77 		gpiod_get_value_cansleep(info->vbus_gpiod) : id;
78 
79 	if (!id)
80 		role = USB_ROLE_HOST;
81 	else if (vbus)
82 		role = USB_ROLE_DEVICE;
83 	else
84 		role = USB_ROLE_NONE;
85 
86 	dev_dbg(info->dev, "role %s -> %s, gpios: id %d, vbus %d\n",
87 		usb_role_string(info->last_role), usb_role_string(role), id, vbus);
88 
89 	if (info->last_role == role) {
90 		dev_warn(info->dev, "repeated role: %s\n", usb_role_string(role));
91 		return;
92 	}
93 
94 	if (info->last_role == USB_ROLE_HOST && info->vbus)
95 		regulator_disable(info->vbus);
96 
97 	ret = usb_role_switch_set_role(info->role_sw, role);
98 	if (ret)
99 		dev_err(info->dev, "failed to set role: %d\n", ret);
100 
101 	if (role == USB_ROLE_HOST && info->vbus) {
102 		ret = regulator_enable(info->vbus);
103 		if (ret)
104 			dev_err(info->dev, "enable vbus regulator failed\n");
105 	}
106 
107 	info->last_role = role;
108 
109 	if (info->vbus)
110 		dev_dbg(info->dev, "vbus regulator is %s\n",
111 			regulator_is_enabled(info->vbus) ? "enabled" : "disabled");
112 
113 	power_supply_changed(info->charger);
114 }
115 
116 static void usb_conn_queue_dwork(struct usb_conn_info *info,
117 				 unsigned long delay)
118 {
119 	queue_delayed_work(system_power_efficient_wq, &info->dw_det, delay);
120 }
121 
122 static irqreturn_t usb_conn_isr(int irq, void *dev_id)
123 {
124 	struct usb_conn_info *info = dev_id;
125 
126 	usb_conn_queue_dwork(info, info->debounce_jiffies);
127 
128 	return IRQ_HANDLED;
129 }
130 
131 static enum power_supply_property usb_charger_properties[] = {
132 	POWER_SUPPLY_PROP_ONLINE,
133 };
134 
135 static int usb_charger_get_property(struct power_supply *psy,
136 				    enum power_supply_property psp,
137 				    union power_supply_propval *val)
138 {
139 	struct usb_conn_info *info = power_supply_get_drvdata(psy);
140 
141 	switch (psp) {
142 	case POWER_SUPPLY_PROP_ONLINE:
143 		val->intval = info->last_role == USB_ROLE_DEVICE;
144 		break;
145 	default:
146 		return -EINVAL;
147 	}
148 
149 	return 0;
150 }
151 
152 static int usb_conn_psy_register(struct usb_conn_info *info)
153 {
154 	struct device *dev = info->dev;
155 	struct power_supply_desc *desc = &info->desc;
156 	struct power_supply_config cfg = {
157 		.of_node = dev->of_node,
158 	};
159 
160 	desc->name = "usb-charger";
161 	desc->properties = usb_charger_properties;
162 	desc->num_properties = ARRAY_SIZE(usb_charger_properties);
163 	desc->get_property = usb_charger_get_property;
164 	desc->type = POWER_SUPPLY_TYPE_USB;
165 	cfg.drv_data = info;
166 
167 	info->charger = devm_power_supply_register(dev, desc, &cfg);
168 	if (IS_ERR(info->charger))
169 		dev_err(dev, "Unable to register charger\n");
170 
171 	return PTR_ERR_OR_ZERO(info->charger);
172 }
173 
174 static int usb_conn_probe(struct platform_device *pdev)
175 {
176 	struct device *dev = &pdev->dev;
177 	struct usb_conn_info *info;
178 	int ret = 0;
179 
180 	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
181 	if (!info)
182 		return -ENOMEM;
183 
184 	info->dev = dev;
185 	info->id_gpiod = devm_gpiod_get_optional(dev, "id", GPIOD_IN);
186 	if (IS_ERR(info->id_gpiod))
187 		return PTR_ERR(info->id_gpiod);
188 
189 	info->vbus_gpiod = devm_gpiod_get_optional(dev, "vbus", GPIOD_IN);
190 	if (IS_ERR(info->vbus_gpiod))
191 		return PTR_ERR(info->vbus_gpiod);
192 
193 	if (!info->id_gpiod && !info->vbus_gpiod) {
194 		dev_err(dev, "failed to get gpios\n");
195 		return -ENODEV;
196 	}
197 
198 	if (info->id_gpiod)
199 		ret = gpiod_set_debounce(info->id_gpiod, USB_GPIO_DEB_US);
200 	if (!ret && info->vbus_gpiod)
201 		ret = gpiod_set_debounce(info->vbus_gpiod, USB_GPIO_DEB_US);
202 	if (ret < 0)
203 		info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEB_MS);
204 
205 	INIT_DELAYED_WORK(&info->dw_det, usb_conn_detect_cable);
206 
207 	info->vbus = devm_regulator_get_optional(dev, "vbus");
208 	if (PTR_ERR(info->vbus) == -ENODEV)
209 		info->vbus = NULL;
210 
211 	if (IS_ERR(info->vbus))
212 		return dev_err_probe(dev, PTR_ERR(info->vbus), "failed to get vbus\n");
213 
214 	info->role_sw = usb_role_switch_get(dev);
215 	if (IS_ERR(info->role_sw))
216 		return dev_err_probe(dev, PTR_ERR(info->role_sw),
217 				     "failed to get role switch\n");
218 
219 	ret = usb_conn_psy_register(info);
220 	if (ret)
221 		goto put_role_sw;
222 
223 	if (info->id_gpiod) {
224 		info->id_irq = gpiod_to_irq(info->id_gpiod);
225 		if (info->id_irq < 0) {
226 			dev_err(dev, "failed to get ID IRQ\n");
227 			ret = info->id_irq;
228 			goto put_role_sw;
229 		}
230 
231 		ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
232 						usb_conn_isr, USB_CONN_IRQF,
233 						pdev->name, info);
234 		if (ret < 0) {
235 			dev_err(dev, "failed to request ID IRQ\n");
236 			goto put_role_sw;
237 		}
238 	}
239 
240 	if (info->vbus_gpiod) {
241 		info->vbus_irq = gpiod_to_irq(info->vbus_gpiod);
242 		if (info->vbus_irq < 0) {
243 			dev_err(dev, "failed to get VBUS IRQ\n");
244 			ret = info->vbus_irq;
245 			goto put_role_sw;
246 		}
247 
248 		ret = devm_request_threaded_irq(dev, info->vbus_irq, NULL,
249 						usb_conn_isr, USB_CONN_IRQF,
250 						pdev->name, info);
251 		if (ret < 0) {
252 			dev_err(dev, "failed to request VBUS IRQ\n");
253 			goto put_role_sw;
254 		}
255 	}
256 
257 	platform_set_drvdata(pdev, info);
258 	device_set_wakeup_capable(&pdev->dev, true);
259 
260 	/* Perform initial detection */
261 	usb_conn_queue_dwork(info, 0);
262 
263 	return 0;
264 
265 put_role_sw:
266 	usb_role_switch_put(info->role_sw);
267 	return ret;
268 }
269 
270 static int usb_conn_remove(struct platform_device *pdev)
271 {
272 	struct usb_conn_info *info = platform_get_drvdata(pdev);
273 
274 	cancel_delayed_work_sync(&info->dw_det);
275 
276 	if (info->last_role == USB_ROLE_HOST && info->vbus)
277 		regulator_disable(info->vbus);
278 
279 	usb_role_switch_put(info->role_sw);
280 
281 	return 0;
282 }
283 
284 static int __maybe_unused usb_conn_suspend(struct device *dev)
285 {
286 	struct usb_conn_info *info = dev_get_drvdata(dev);
287 
288 	if (device_may_wakeup(dev)) {
289 		if (info->id_gpiod)
290 			enable_irq_wake(info->id_irq);
291 		if (info->vbus_gpiod)
292 			enable_irq_wake(info->vbus_irq);
293 		return 0;
294 	}
295 
296 	if (info->id_gpiod)
297 		disable_irq(info->id_irq);
298 	if (info->vbus_gpiod)
299 		disable_irq(info->vbus_irq);
300 
301 	pinctrl_pm_select_sleep_state(dev);
302 
303 	return 0;
304 }
305 
306 static int __maybe_unused usb_conn_resume(struct device *dev)
307 {
308 	struct usb_conn_info *info = dev_get_drvdata(dev);
309 
310 	if (device_may_wakeup(dev)) {
311 		if (info->id_gpiod)
312 			disable_irq_wake(info->id_irq);
313 		if (info->vbus_gpiod)
314 			disable_irq_wake(info->vbus_irq);
315 		return 0;
316 	}
317 
318 	pinctrl_pm_select_default_state(dev);
319 
320 	if (info->id_gpiod)
321 		enable_irq(info->id_irq);
322 	if (info->vbus_gpiod)
323 		enable_irq(info->vbus_irq);
324 
325 	usb_conn_queue_dwork(info, 0);
326 
327 	return 0;
328 }
329 
330 static SIMPLE_DEV_PM_OPS(usb_conn_pm_ops,
331 			 usb_conn_suspend, usb_conn_resume);
332 
333 static const struct of_device_id usb_conn_dt_match[] = {
334 	{ .compatible = "gpio-usb-b-connector", },
335 	{ }
336 };
337 MODULE_DEVICE_TABLE(of, usb_conn_dt_match);
338 
339 static struct platform_driver usb_conn_driver = {
340 	.probe		= usb_conn_probe,
341 	.remove		= usb_conn_remove,
342 	.driver		= {
343 		.name	= "usb-conn-gpio",
344 		.pm	= &usb_conn_pm_ops,
345 		.of_match_table = usb_conn_dt_match,
346 	},
347 };
348 
349 module_platform_driver(usb_conn_driver);
350 
351 MODULE_AUTHOR("Chunfeng Yun <chunfeng.yun@mediatek.com>");
352 MODULE_DESCRIPTION("USB GPIO based connection detection driver");
353 MODULE_LICENSE("GPL v2");
354