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 	bool need_vbus = true;
179 	int ret = 0;
180 
181 	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
182 	if (!info)
183 		return -ENOMEM;
184 
185 	info->dev = dev;
186 	info->id_gpiod = devm_gpiod_get_optional(dev, "id", GPIOD_IN);
187 	if (IS_ERR(info->id_gpiod))
188 		return PTR_ERR(info->id_gpiod);
189 
190 	info->vbus_gpiod = devm_gpiod_get_optional(dev, "vbus", GPIOD_IN);
191 	if (IS_ERR(info->vbus_gpiod))
192 		return PTR_ERR(info->vbus_gpiod);
193 
194 	if (!info->id_gpiod && !info->vbus_gpiod) {
195 		dev_err(dev, "failed to get gpios\n");
196 		return -ENODEV;
197 	}
198 
199 	if (info->id_gpiod)
200 		ret = gpiod_set_debounce(info->id_gpiod, USB_GPIO_DEB_US);
201 	if (!ret && info->vbus_gpiod)
202 		ret = gpiod_set_debounce(info->vbus_gpiod, USB_GPIO_DEB_US);
203 	if (ret < 0)
204 		info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEB_MS);
205 
206 	INIT_DELAYED_WORK(&info->dw_det, usb_conn_detect_cable);
207 
208 	/*
209 	 * If the USB connector is a child of a USB port and that port already provides the VBUS
210 	 * supply, there's no need for the USB connector to provide it again.
211 	 */
212 	if (dev->parent && dev->parent->of_node) {
213 		if (of_find_property(dev->parent->of_node, "vbus-supply", NULL))
214 			need_vbus = false;
215 	}
216 
217 	if (!need_vbus) {
218 		info->vbus = devm_regulator_get_optional(dev, "vbus");
219 		if (PTR_ERR(info->vbus) == -ENODEV)
220 			info->vbus = NULL;
221 	} else {
222 		info->vbus = devm_regulator_get(dev, "vbus");
223 	}
224 
225 	if (IS_ERR(info->vbus)) {
226 		ret = PTR_ERR(info->vbus);
227 		return dev_err_probe(dev, ret, "failed to get vbus :%d\n", ret);
228 	}
229 
230 	info->role_sw = usb_role_switch_get(dev);
231 	if (IS_ERR(info->role_sw))
232 		return dev_err_probe(dev, PTR_ERR(info->role_sw),
233 				     "failed to get role switch\n");
234 
235 	ret = usb_conn_psy_register(info);
236 	if (ret)
237 		goto put_role_sw;
238 
239 	if (info->id_gpiod) {
240 		info->id_irq = gpiod_to_irq(info->id_gpiod);
241 		if (info->id_irq < 0) {
242 			dev_err(dev, "failed to get ID IRQ\n");
243 			ret = info->id_irq;
244 			goto put_role_sw;
245 		}
246 
247 		ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
248 						usb_conn_isr, USB_CONN_IRQF,
249 						pdev->name, info);
250 		if (ret < 0) {
251 			dev_err(dev, "failed to request ID IRQ\n");
252 			goto put_role_sw;
253 		}
254 	}
255 
256 	if (info->vbus_gpiod) {
257 		info->vbus_irq = gpiod_to_irq(info->vbus_gpiod);
258 		if (info->vbus_irq < 0) {
259 			dev_err(dev, "failed to get VBUS IRQ\n");
260 			ret = info->vbus_irq;
261 			goto put_role_sw;
262 		}
263 
264 		ret = devm_request_threaded_irq(dev, info->vbus_irq, NULL,
265 						usb_conn_isr, USB_CONN_IRQF,
266 						pdev->name, info);
267 		if (ret < 0) {
268 			dev_err(dev, "failed to request VBUS IRQ\n");
269 			goto put_role_sw;
270 		}
271 	}
272 
273 	platform_set_drvdata(pdev, info);
274 
275 	/* Perform initial detection */
276 	usb_conn_queue_dwork(info, 0);
277 
278 	return 0;
279 
280 put_role_sw:
281 	usb_role_switch_put(info->role_sw);
282 	return ret;
283 }
284 
285 static int usb_conn_remove(struct platform_device *pdev)
286 {
287 	struct usb_conn_info *info = platform_get_drvdata(pdev);
288 
289 	cancel_delayed_work_sync(&info->dw_det);
290 
291 	if (info->last_role == USB_ROLE_HOST && info->vbus)
292 		regulator_disable(info->vbus);
293 
294 	usb_role_switch_put(info->role_sw);
295 
296 	return 0;
297 }
298 
299 static int __maybe_unused usb_conn_suspend(struct device *dev)
300 {
301 	struct usb_conn_info *info = dev_get_drvdata(dev);
302 
303 	if (info->id_gpiod)
304 		disable_irq(info->id_irq);
305 	if (info->vbus_gpiod)
306 		disable_irq(info->vbus_irq);
307 
308 	pinctrl_pm_select_sleep_state(dev);
309 
310 	return 0;
311 }
312 
313 static int __maybe_unused usb_conn_resume(struct device *dev)
314 {
315 	struct usb_conn_info *info = dev_get_drvdata(dev);
316 
317 	pinctrl_pm_select_default_state(dev);
318 
319 	if (info->id_gpiod)
320 		enable_irq(info->id_irq);
321 	if (info->vbus_gpiod)
322 		enable_irq(info->vbus_irq);
323 
324 	usb_conn_queue_dwork(info, 0);
325 
326 	return 0;
327 }
328 
329 static SIMPLE_DEV_PM_OPS(usb_conn_pm_ops,
330 			 usb_conn_suspend, usb_conn_resume);
331 
332 static const struct of_device_id usb_conn_dt_match[] = {
333 	{ .compatible = "gpio-usb-b-connector", },
334 	{ }
335 };
336 MODULE_DEVICE_TABLE(of, usb_conn_dt_match);
337 
338 static struct platform_driver usb_conn_driver = {
339 	.probe		= usb_conn_probe,
340 	.remove		= usb_conn_remove,
341 	.driver		= {
342 		.name	= "usb-conn-gpio",
343 		.pm	= &usb_conn_pm_ops,
344 		.of_match_table = usb_conn_dt_match,
345 	},
346 };
347 
348 module_platform_driver(usb_conn_driver);
349 
350 MODULE_AUTHOR("Chunfeng Yun <chunfeng.yun@mediatek.com>");
351 MODULE_DESCRIPTION("USB GPIO based connection detection driver");
352 MODULE_LICENSE("GPL v2");
353