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/regulator/consumer.h>
 21#include <linux/usb/role.h>
 22
 23#define USB_GPIO_DEB_MS		20	/* ms */
 24#define USB_GPIO_DEB_US		((USB_GPIO_DEB_MS) * 1000)	/* us */
 25
 26#define USB_CONN_IRQF	\
 27	(IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT)
 28
 29struct usb_conn_info {
 30	struct device *dev;
 31	struct usb_role_switch *role_sw;
 32	enum usb_role last_role;
 33	struct regulator *vbus;
 34	struct delayed_work dw_det;
 35	unsigned long debounce_jiffies;
 36
 37	struct gpio_desc *id_gpiod;
 38	struct gpio_desc *vbus_gpiod;
 39	int id_irq;
 40	int vbus_irq;
 41};
 42
 43/**
 44 * "DEVICE" = VBUS and "HOST" = !ID, so we have:
 45 * Both "DEVICE" and "HOST" can't be set as active at the same time
 46 * so if "HOST" is active (i.e. ID is 0)  we keep "DEVICE" inactive
 47 * even if VBUS is on.
 48 *
 49 *  Role          |   ID  |  VBUS
 50 * ------------------------------------
 51 *  [1] DEVICE    |   H   |   H
 52 *  [2] NONE      |   H   |   L
 53 *  [3] HOST      |   L   |   H
 54 *  [4] HOST      |   L   |   L
 55 *
 56 * In case we have only one of these signals:
 57 * - VBUS only - we want to distinguish between [1] and [2], so ID is always 1
 58 * - ID only - we want to distinguish between [1] and [4], so VBUS = ID
 59 */
 60static void usb_conn_detect_cable(struct work_struct *work)
 61{
 62	struct usb_conn_info *info;
 63	enum usb_role role;
 64	int id, vbus, ret;
 65
 66	info = container_of(to_delayed_work(work),
 67			    struct usb_conn_info, dw_det);
 68
 69	/* check ID and VBUS */
 70	id = info->id_gpiod ?
 71		gpiod_get_value_cansleep(info->id_gpiod) : 1;
 72	vbus = info->vbus_gpiod ?
 73		gpiod_get_value_cansleep(info->vbus_gpiod) : id;
 74
 75	if (!id)
 76		role = USB_ROLE_HOST;
 77	else if (vbus)
 78		role = USB_ROLE_DEVICE;
 79	else
 80		role = USB_ROLE_NONE;
 81
 82	dev_dbg(info->dev, "role %d/%d, gpios: id %d, vbus %d\n",
 83		info->last_role, role, id, vbus);
 84
 85	if (info->last_role == role) {
 86		dev_warn(info->dev, "repeated role: %d\n", role);
 87		return;
 88	}
 89
 90	if (info->last_role == USB_ROLE_HOST)
 91		regulator_disable(info->vbus);
 92
 93	ret = usb_role_switch_set_role(info->role_sw, role);
 94	if (ret)
 95		dev_err(info->dev, "failed to set role: %d\n", ret);
 96
 97	if (role == USB_ROLE_HOST) {
 98		ret = regulator_enable(info->vbus);
 99		if (ret)
100			dev_err(info->dev, "enable vbus regulator failed\n");
101	}
102
103	info->last_role = role;
104
105	dev_dbg(info->dev, "vbus regulator is %s\n",
106		regulator_is_enabled(info->vbus) ? "enabled" : "disabled");
107}
108
109static void usb_conn_queue_dwork(struct usb_conn_info *info,
110				 unsigned long delay)
111{
112	queue_delayed_work(system_power_efficient_wq, &info->dw_det, delay);
113}
114
115static irqreturn_t usb_conn_isr(int irq, void *dev_id)
116{
117	struct usb_conn_info *info = dev_id;
118
119	usb_conn_queue_dwork(info, info->debounce_jiffies);
120
121	return IRQ_HANDLED;
122}
123
124static int usb_conn_probe(struct platform_device *pdev)
125{
126	struct device *dev = &pdev->dev;
127	struct usb_conn_info *info;
128	int ret = 0;
129
130	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
131	if (!info)
132		return -ENOMEM;
133
134	info->dev = dev;
135	info->id_gpiod = devm_gpiod_get_optional(dev, "id", GPIOD_IN);
136	if (IS_ERR(info->id_gpiod))
137		return PTR_ERR(info->id_gpiod);
138
139	info->vbus_gpiod = devm_gpiod_get_optional(dev, "vbus", GPIOD_IN);
140	if (IS_ERR(info->vbus_gpiod))
141		return PTR_ERR(info->vbus_gpiod);
142
143	if (!info->id_gpiod && !info->vbus_gpiod) {
144		dev_err(dev, "failed to get gpios\n");
145		return -ENODEV;
146	}
147
148	if (info->id_gpiod)
149		ret = gpiod_set_debounce(info->id_gpiod, USB_GPIO_DEB_US);
150	if (!ret && info->vbus_gpiod)
151		ret = gpiod_set_debounce(info->vbus_gpiod, USB_GPIO_DEB_US);
152	if (ret < 0)
153		info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEB_MS);
154
155	INIT_DELAYED_WORK(&info->dw_det, usb_conn_detect_cable);
156
157	info->vbus = devm_regulator_get(dev, "vbus");
158	if (IS_ERR(info->vbus)) {
159		dev_err(dev, "failed to get vbus\n");
160		return PTR_ERR(info->vbus);
161	}
162
163	info->role_sw = usb_role_switch_get(dev);
164	if (IS_ERR(info->role_sw)) {
165		if (PTR_ERR(info->role_sw) != -EPROBE_DEFER)
166			dev_err(dev, "failed to get role switch\n");
167
168		return PTR_ERR(info->role_sw);
169	}
170
171	if (info->id_gpiod) {
172		info->id_irq = gpiod_to_irq(info->id_gpiod);
173		if (info->id_irq < 0) {
174			dev_err(dev, "failed to get ID IRQ\n");
175			ret = info->id_irq;
176			goto put_role_sw;
177		}
178
179		ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
180						usb_conn_isr, USB_CONN_IRQF,
181						pdev->name, info);
182		if (ret < 0) {
183			dev_err(dev, "failed to request ID IRQ\n");
184			goto put_role_sw;
185		}
186	}
187
188	if (info->vbus_gpiod) {
189		info->vbus_irq = gpiod_to_irq(info->vbus_gpiod);
190		if (info->vbus_irq < 0) {
191			dev_err(dev, "failed to get VBUS IRQ\n");
192			ret = info->vbus_irq;
193			goto put_role_sw;
194		}
195
196		ret = devm_request_threaded_irq(dev, info->vbus_irq, NULL,
197						usb_conn_isr, USB_CONN_IRQF,
198						pdev->name, info);
199		if (ret < 0) {
200			dev_err(dev, "failed to request VBUS IRQ\n");
201			goto put_role_sw;
202		}
203	}
204
205	platform_set_drvdata(pdev, info);
206
207	/* Perform initial detection */
208	usb_conn_queue_dwork(info, 0);
209
210	return 0;
211
212put_role_sw:
213	usb_role_switch_put(info->role_sw);
214	return ret;
215}
216
217static int usb_conn_remove(struct platform_device *pdev)
218{
219	struct usb_conn_info *info = platform_get_drvdata(pdev);
220
221	cancel_delayed_work_sync(&info->dw_det);
222
223	if (info->last_role == USB_ROLE_HOST)
224		regulator_disable(info->vbus);
225
226	usb_role_switch_put(info->role_sw);
227
228	return 0;
229}
230
231static int __maybe_unused usb_conn_suspend(struct device *dev)
232{
233	struct usb_conn_info *info = dev_get_drvdata(dev);
234
235	if (info->id_gpiod)
236		disable_irq(info->id_irq);
237	if (info->vbus_gpiod)
238		disable_irq(info->vbus_irq);
239
240	pinctrl_pm_select_sleep_state(dev);
241
242	return 0;
243}
244
245static int __maybe_unused usb_conn_resume(struct device *dev)
246{
247	struct usb_conn_info *info = dev_get_drvdata(dev);
248
249	pinctrl_pm_select_default_state(dev);
250
251	if (info->id_gpiod)
252		enable_irq(info->id_irq);
253	if (info->vbus_gpiod)
254		enable_irq(info->vbus_irq);
255
256	usb_conn_queue_dwork(info, 0);
257
258	return 0;
259}
260
261static SIMPLE_DEV_PM_OPS(usb_conn_pm_ops,
262			 usb_conn_suspend, usb_conn_resume);
263
264static const struct of_device_id usb_conn_dt_match[] = {
265	{ .compatible = "gpio-usb-b-connector", },
266	{ }
267};
268MODULE_DEVICE_TABLE(of, usb_conn_dt_match);
269
270static struct platform_driver usb_conn_driver = {
271	.probe		= usb_conn_probe,
272	.remove		= usb_conn_remove,
273	.driver		= {
274		.name	= "usb-conn-gpio",
275		.pm	= &usb_conn_pm_ops,
276		.of_match_table = usb_conn_dt_match,
277	},
278};
279
280module_platform_driver(usb_conn_driver);
281
282MODULE_AUTHOR("Chunfeng Yun <chunfeng.yun@mediatek.com>");
283MODULE_DESCRIPTION("USB GPIO based connection detection driver");
284MODULE_LICENSE("GPL v2");