1/**
  2 * drivers/extcon/extcon-usb-gpio.c - USB GPIO extcon driver
  3 *
  4 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
  5 * Author: Roger Quadros <rogerq@ti.com>
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License version 2 as
  9 * published by the Free Software Foundation.
 10 *
 11 * This program is distributed in the hope that it will be useful,
 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14 * GNU General Public License for more details.
 15 */
 16
 17#include <linux/extcon.h>
 18#include <linux/gpio.h>
 19#include <linux/gpio/consumer.h>
 20#include <linux/init.h>
 21#include <linux/interrupt.h>
 22#include <linux/irq.h>
 23#include <linux/kernel.h>
 24#include <linux/module.h>
 25#include <linux/of_gpio.h>
 26#include <linux/platform_device.h>
 27#include <linux/slab.h>
 28#include <linux/workqueue.h>
 29
 30#define USB_GPIO_DEBOUNCE_MS	20	/* ms */
 31
 32struct usb_extcon_info {
 33	struct device *dev;
 34	struct extcon_dev *edev;
 35
 36	struct gpio_desc *id_gpiod;
 37	int id_irq;
 38
 39	unsigned long debounce_jiffies;
 40	struct delayed_work wq_detcable;
 41};
 42
 43static const unsigned int usb_extcon_cable[] = {
 44	EXTCON_USB,
 45	EXTCON_USB_HOST,
 46	EXTCON_NONE,
 47};
 48
 49static void usb_extcon_detect_cable(struct work_struct *work)
 50{
 51	int id;
 52	struct usb_extcon_info *info = container_of(to_delayed_work(work),
 53						    struct usb_extcon_info,
 54						    wq_detcable);
 55
 56	/* check ID and update cable state */
 57	id = gpiod_get_value_cansleep(info->id_gpiod);
 58	if (id) {
 59		/*
 60		 * ID = 1 means USB HOST cable detached.
 61		 * As we don't have event for USB peripheral cable attached,
 62		 * we simulate USB peripheral attach here.
 63		 */
 64		extcon_set_cable_state_(info->edev, EXTCON_USB_HOST, false);
 65		extcon_set_cable_state_(info->edev, EXTCON_USB, true);
 66	} else {
 67		/*
 68		 * ID = 0 means USB HOST cable attached.
 69		 * As we don't have event for USB peripheral cable detached,
 70		 * we simulate USB peripheral detach here.
 71		 */
 72		extcon_set_cable_state_(info->edev, EXTCON_USB, false);
 73		extcon_set_cable_state_(info->edev, EXTCON_USB_HOST, true);
 74	}
 75}
 76
 77static irqreturn_t usb_irq_handler(int irq, void *dev_id)
 78{
 79	struct usb_extcon_info *info = dev_id;
 80
 81	queue_delayed_work(system_power_efficient_wq, &info->wq_detcable,
 82			   info->debounce_jiffies);
 83
 84	return IRQ_HANDLED;
 85}
 86
 87static int usb_extcon_probe(struct platform_device *pdev)
 88{
 89	struct device *dev = &pdev->dev;
 90	struct device_node *np = dev->of_node;
 91	struct usb_extcon_info *info;
 92	int ret;
 93
 94	if (!np)
 95		return -EINVAL;
 96
 97	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
 98	if (!info)
 99		return -ENOMEM;
100
101	info->dev = dev;
102	info->id_gpiod = devm_gpiod_get(&pdev->dev, "id", GPIOD_IN);
103	if (IS_ERR(info->id_gpiod)) {
104		dev_err(dev, "failed to get ID GPIO\n");
105		return PTR_ERR(info->id_gpiod);
106	}
107
108	info->edev = devm_extcon_dev_allocate(dev, usb_extcon_cable);
109	if (IS_ERR(info->edev)) {
110		dev_err(dev, "failed to allocate extcon device\n");
111		return -ENOMEM;
112	}
113
114	ret = devm_extcon_dev_register(dev, info->edev);
115	if (ret < 0) {
116		dev_err(dev, "failed to register extcon device\n");
117		return ret;
118	}
119
120	ret = gpiod_set_debounce(info->id_gpiod,
121				 USB_GPIO_DEBOUNCE_MS * 1000);
122	if (ret < 0)
123		info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEBOUNCE_MS);
124
125	INIT_DELAYED_WORK(&info->wq_detcable, usb_extcon_detect_cable);
126
127	info->id_irq = gpiod_to_irq(info->id_gpiod);
128	if (info->id_irq < 0) {
129		dev_err(dev, "failed to get ID IRQ\n");
130		return info->id_irq;
131	}
132
133	ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
134					usb_irq_handler,
135					IRQF_TRIGGER_RISING |
136					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
137					pdev->name, info);
138	if (ret < 0) {
139		dev_err(dev, "failed to request handler for ID IRQ\n");
140		return ret;
141	}
142
143	platform_set_drvdata(pdev, info);
144	device_init_wakeup(dev, 1);
145
146	/* Perform initial detection */
147	usb_extcon_detect_cable(&info->wq_detcable.work);
148
149	return 0;
150}
151
152static int usb_extcon_remove(struct platform_device *pdev)
153{
154	struct usb_extcon_info *info = platform_get_drvdata(pdev);
155
156	cancel_delayed_work_sync(&info->wq_detcable);
157
158	return 0;
159}
160
161#ifdef CONFIG_PM_SLEEP
162static int usb_extcon_suspend(struct device *dev)
163{
164	struct usb_extcon_info *info = dev_get_drvdata(dev);
165	int ret = 0;
166
167	if (device_may_wakeup(dev)) {
168		ret = enable_irq_wake(info->id_irq);
169		if (ret)
170			return ret;
171	}
172
173	/*
174	 * We don't want to process any IRQs after this point
175	 * as GPIOs used behind I2C subsystem might not be
176	 * accessible until resume completes. So disable IRQ.
177	 */
178	disable_irq(info->id_irq);
179
180	return ret;
181}
182
183static int usb_extcon_resume(struct device *dev)
184{
185	struct usb_extcon_info *info = dev_get_drvdata(dev);
186	int ret = 0;
187
188	if (device_may_wakeup(dev)) {
189		ret = disable_irq_wake(info->id_irq);
190		if (ret)
191			return ret;
192	}
193
194	enable_irq(info->id_irq);
195
196	return ret;
197}
198#endif
199
200static SIMPLE_DEV_PM_OPS(usb_extcon_pm_ops,
201			 usb_extcon_suspend, usb_extcon_resume);
202
203static const struct of_device_id usb_extcon_dt_match[] = {
204	{ .compatible = "linux,extcon-usb-gpio", },
205	{ /* sentinel */ }
206};
207MODULE_DEVICE_TABLE(of, usb_extcon_dt_match);
208
209static struct platform_driver usb_extcon_driver = {
210	.probe		= usb_extcon_probe,
211	.remove		= usb_extcon_remove,
212	.driver		= {
213		.name	= "extcon-usb-gpio",
214		.pm	= &usb_extcon_pm_ops,
215		.of_match_table = usb_extcon_dt_match,
216	},
217};
218
219module_platform_driver(usb_extcon_driver);
220
221MODULE_AUTHOR("Roger Quadros <rogerq@ti.com>");
222MODULE_DESCRIPTION("USB GPIO extcon driver");
223MODULE_LICENSE("GPL v2");