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 bool initial_detection;
46 };
47
48 /*
49 * "DEVICE" = VBUS and "HOST" = !ID, so we have:
50 * Both "DEVICE" and "HOST" can't be set as active at the same time
51 * so if "HOST" is active (i.e. ID is 0) we keep "DEVICE" inactive
52 * even if VBUS is on.
53 *
54 * Role | ID | VBUS
55 * ------------------------------------
56 * [1] DEVICE | H | H
57 * [2] NONE | H | L
58 * [3] HOST | L | H
59 * [4] HOST | L | L
60 *
61 * In case we have only one of these signals:
62 * - VBUS only - we want to distinguish between [1] and [2], so ID is always 1
63 * - ID only - we want to distinguish between [1] and [4], so VBUS = ID
64 */
usb_conn_detect_cable(struct work_struct * work)65 static void usb_conn_detect_cable(struct work_struct *work)
66 {
67 struct usb_conn_info *info;
68 enum usb_role role;
69 int id, vbus, ret;
70
71 info = container_of(to_delayed_work(work),
72 struct usb_conn_info, dw_det);
73
74 /* check ID and VBUS */
75 id = info->id_gpiod ?
76 gpiod_get_value_cansleep(info->id_gpiod) : 1;
77 vbus = info->vbus_gpiod ?
78 gpiod_get_value_cansleep(info->vbus_gpiod) : id;
79
80 if (!id)
81 role = USB_ROLE_HOST;
82 else if (vbus)
83 role = USB_ROLE_DEVICE;
84 else
85 role = USB_ROLE_NONE;
86
87 dev_dbg(info->dev, "role %s -> %s, gpios: id %d, vbus %d\n",
88 usb_role_string(info->last_role), usb_role_string(role), id, vbus);
89
90 if (!info->initial_detection && info->last_role == role) {
91 dev_warn(info->dev, "repeated role: %s\n", usb_role_string(role));
92 return;
93 }
94
95 info->initial_detection = false;
96
97 if (info->last_role == USB_ROLE_HOST && info->vbus)
98 regulator_disable(info->vbus);
99
100 ret = usb_role_switch_set_role(info->role_sw, role);
101 if (ret)
102 dev_err(info->dev, "failed to set role: %d\n", ret);
103
104 if (role == USB_ROLE_HOST && info->vbus) {
105 ret = regulator_enable(info->vbus);
106 if (ret)
107 dev_err(info->dev, "enable vbus regulator failed\n");
108 }
109
110 info->last_role = role;
111
112 if (info->vbus)
113 dev_dbg(info->dev, "vbus regulator is %s\n",
114 regulator_is_enabled(info->vbus) ? "enabled" : "disabled");
115
116 power_supply_changed(info->charger);
117 }
118
usb_conn_queue_dwork(struct usb_conn_info * info,unsigned long delay)119 static void usb_conn_queue_dwork(struct usb_conn_info *info,
120 unsigned long delay)
121 {
122 queue_delayed_work(system_power_efficient_wq, &info->dw_det, delay);
123 }
124
usb_conn_isr(int irq,void * dev_id)125 static irqreturn_t usb_conn_isr(int irq, void *dev_id)
126 {
127 struct usb_conn_info *info = dev_id;
128
129 usb_conn_queue_dwork(info, info->debounce_jiffies);
130
131 return IRQ_HANDLED;
132 }
133
134 static enum power_supply_property usb_charger_properties[] = {
135 POWER_SUPPLY_PROP_ONLINE,
136 };
137
usb_charger_get_property(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)138 static int usb_charger_get_property(struct power_supply *psy,
139 enum power_supply_property psp,
140 union power_supply_propval *val)
141 {
142 struct usb_conn_info *info = power_supply_get_drvdata(psy);
143
144 switch (psp) {
145 case POWER_SUPPLY_PROP_ONLINE:
146 val->intval = info->last_role == USB_ROLE_DEVICE;
147 break;
148 default:
149 return -EINVAL;
150 }
151
152 return 0;
153 }
154
usb_conn_psy_register(struct usb_conn_info * info)155 static int usb_conn_psy_register(struct usb_conn_info *info)
156 {
157 struct device *dev = info->dev;
158 struct power_supply_desc *desc = &info->desc;
159 struct power_supply_config cfg = {
160 .of_node = dev->of_node,
161 };
162
163 desc->name = "usb-charger";
164 desc->properties = usb_charger_properties;
165 desc->num_properties = ARRAY_SIZE(usb_charger_properties);
166 desc->get_property = usb_charger_get_property;
167 desc->type = POWER_SUPPLY_TYPE_USB;
168 cfg.drv_data = info;
169
170 info->charger = devm_power_supply_register(dev, desc, &cfg);
171 if (IS_ERR(info->charger))
172 dev_err(dev, "Unable to register charger\n");
173
174 return PTR_ERR_OR_ZERO(info->charger);
175 }
176
usb_conn_probe(struct platform_device * pdev)177 static int usb_conn_probe(struct platform_device *pdev)
178 {
179 struct device *dev = &pdev->dev;
180 struct usb_conn_info *info;
181 int ret = 0;
182
183 info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
184 if (!info)
185 return -ENOMEM;
186
187 info->dev = dev;
188 info->id_gpiod = devm_gpiod_get_optional(dev, "id", GPIOD_IN);
189 if (IS_ERR(info->id_gpiod))
190 return PTR_ERR(info->id_gpiod);
191
192 info->vbus_gpiod = devm_gpiod_get_optional(dev, "vbus", GPIOD_IN);
193 if (IS_ERR(info->vbus_gpiod))
194 return PTR_ERR(info->vbus_gpiod);
195
196 if (!info->id_gpiod && !info->vbus_gpiod) {
197 dev_err(dev, "failed to get gpios\n");
198 return -ENODEV;
199 }
200
201 if (info->id_gpiod)
202 ret = gpiod_set_debounce(info->id_gpiod, USB_GPIO_DEB_US);
203 if (!ret && info->vbus_gpiod)
204 ret = gpiod_set_debounce(info->vbus_gpiod, USB_GPIO_DEB_US);
205 if (ret < 0)
206 info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEB_MS);
207
208 INIT_DELAYED_WORK(&info->dw_det, usb_conn_detect_cable);
209
210 info->vbus = devm_regulator_get_optional(dev, "vbus");
211 if (PTR_ERR(info->vbus) == -ENODEV)
212 info->vbus = NULL;
213
214 if (IS_ERR(info->vbus))
215 return dev_err_probe(dev, PTR_ERR(info->vbus), "failed to get vbus\n");
216
217 info->role_sw = usb_role_switch_get(dev);
218 if (IS_ERR(info->role_sw))
219 return dev_err_probe(dev, PTR_ERR(info->role_sw),
220 "failed to get role switch\n");
221
222 ret = usb_conn_psy_register(info);
223 if (ret)
224 goto put_role_sw;
225
226 if (info->id_gpiod) {
227 info->id_irq = gpiod_to_irq(info->id_gpiod);
228 if (info->id_irq < 0) {
229 dev_err(dev, "failed to get ID IRQ\n");
230 ret = info->id_irq;
231 goto put_role_sw;
232 }
233
234 ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
235 usb_conn_isr, USB_CONN_IRQF,
236 pdev->name, info);
237 if (ret < 0) {
238 dev_err(dev, "failed to request ID IRQ\n");
239 goto put_role_sw;
240 }
241 }
242
243 if (info->vbus_gpiod) {
244 info->vbus_irq = gpiod_to_irq(info->vbus_gpiod);
245 if (info->vbus_irq < 0) {
246 dev_err(dev, "failed to get VBUS IRQ\n");
247 ret = info->vbus_irq;
248 goto put_role_sw;
249 }
250
251 ret = devm_request_threaded_irq(dev, info->vbus_irq, NULL,
252 usb_conn_isr, USB_CONN_IRQF,
253 pdev->name, info);
254 if (ret < 0) {
255 dev_err(dev, "failed to request VBUS IRQ\n");
256 goto put_role_sw;
257 }
258 }
259
260 platform_set_drvdata(pdev, info);
261 device_set_wakeup_capable(&pdev->dev, true);
262
263 /* Perform initial detection */
264 info->initial_detection = true;
265 usb_conn_queue_dwork(info, 0);
266
267 return 0;
268
269 put_role_sw:
270 usb_role_switch_put(info->role_sw);
271 return ret;
272 }
273
usb_conn_remove(struct platform_device * pdev)274 static void usb_conn_remove(struct platform_device *pdev)
275 {
276 struct usb_conn_info *info = platform_get_drvdata(pdev);
277
278 cancel_delayed_work_sync(&info->dw_det);
279
280 if (info->last_role == USB_ROLE_HOST && info->vbus)
281 regulator_disable(info->vbus);
282
283 usb_role_switch_put(info->role_sw);
284 }
285
usb_conn_suspend(struct device * dev)286 static int __maybe_unused usb_conn_suspend(struct device *dev)
287 {
288 struct usb_conn_info *info = dev_get_drvdata(dev);
289
290 if (device_may_wakeup(dev)) {
291 if (info->id_gpiod)
292 enable_irq_wake(info->id_irq);
293 if (info->vbus_gpiod)
294 enable_irq_wake(info->vbus_irq);
295 return 0;
296 }
297
298 if (info->id_gpiod)
299 disable_irq(info->id_irq);
300 if (info->vbus_gpiod)
301 disable_irq(info->vbus_irq);
302
303 pinctrl_pm_select_sleep_state(dev);
304
305 return 0;
306 }
307
usb_conn_resume(struct device * dev)308 static int __maybe_unused usb_conn_resume(struct device *dev)
309 {
310 struct usb_conn_info *info = dev_get_drvdata(dev);
311
312 if (device_may_wakeup(dev)) {
313 if (info->id_gpiod)
314 disable_irq_wake(info->id_irq);
315 if (info->vbus_gpiod)
316 disable_irq_wake(info->vbus_irq);
317 return 0;
318 }
319
320 pinctrl_pm_select_default_state(dev);
321
322 if (info->id_gpiod)
323 enable_irq(info->id_irq);
324 if (info->vbus_gpiod)
325 enable_irq(info->vbus_irq);
326
327 usb_conn_queue_dwork(info, 0);
328
329 return 0;
330 }
331
332 static SIMPLE_DEV_PM_OPS(usb_conn_pm_ops,
333 usb_conn_suspend, usb_conn_resume);
334
335 static const struct of_device_id usb_conn_dt_match[] = {
336 { .compatible = "gpio-usb-b-connector", },
337 { }
338 };
339 MODULE_DEVICE_TABLE(of, usb_conn_dt_match);
340
341 static struct platform_driver usb_conn_driver = {
342 .probe = usb_conn_probe,
343 .remove_new = usb_conn_remove,
344 .driver = {
345 .name = "usb-conn-gpio",
346 .pm = &usb_conn_pm_ops,
347 .of_match_table = usb_conn_dt_match,
348 },
349 };
350
351 module_platform_driver(usb_conn_driver);
352
353 MODULE_AUTHOR("Chunfeng Yun <chunfeng.yun@mediatek.com>");
354 MODULE_DESCRIPTION("USB GPIO based connection detection driver");
355 MODULE_LICENSE("GPL v2");
356