1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * extcon_gpio.c - Single-state GPIO extcon driver based on extcon class
4 *
5 * Copyright (C) 2008 Google, Inc.
6 * Author: Mike Lockwood <lockwood@android.com>
7 *
8 * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
9 * (originally switch class is supported)
10 */
11
12#include <linux/devm-helpers.h>
13#include <linux/extcon-provider.h>
14#include <linux/gpio/consumer.h>
15#include <linux/init.h>
16#include <linux/interrupt.h>
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/platform_device.h>
20#include <linux/slab.h>
21#include <linux/workqueue.h>
22
23/**
24 * struct gpio_extcon_data - A simple GPIO-controlled extcon device state container.
25 * @edev:		Extcon device.
26 * @work:		Work fired by the interrupt.
27 * @debounce_jiffies:	Number of jiffies to wait for the GPIO to stabilize, from the debounce
28 *			value.
29 * @gpiod:		GPIO descriptor for this external connector.
30 * @extcon_id:		The unique id of specific external connector.
31 * @debounce:		Debounce time for GPIO IRQ in ms.
32 * @check_on_resume:	Boolean describing whether to check the state of gpio
33 *			while resuming from sleep.
34 */
35struct gpio_extcon_data {
36	struct extcon_dev *edev;
37	struct delayed_work work;
38	unsigned long debounce_jiffies;
39	struct gpio_desc *gpiod;
40	unsigned int extcon_id;
41	unsigned long debounce;
42	bool check_on_resume;
43};
44
45static void gpio_extcon_work(struct work_struct *work)
46{
47	int state;
48	struct gpio_extcon_data	*data =
49		container_of(to_delayed_work(work), struct gpio_extcon_data,
50			     work);
51
52	state = gpiod_get_value_cansleep(data->gpiod);
53	extcon_set_state_sync(data->edev, data->extcon_id, state);
54}
55
56static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
57{
58	struct gpio_extcon_data *data = dev_id;
59
60	queue_delayed_work(system_power_efficient_wq, &data->work,
61			      data->debounce_jiffies);
62	return IRQ_HANDLED;
63}
64
65static int gpio_extcon_probe(struct platform_device *pdev)
66{
67	struct gpio_extcon_data *data;
68	struct device *dev = &pdev->dev;
69	unsigned long irq_flags;
70	int irq;
71	int ret;
72
73	data = devm_kzalloc(dev, sizeof(struct gpio_extcon_data), GFP_KERNEL);
74	if (!data)
75		return -ENOMEM;
76
77	/*
78	 * FIXME: extcon_id represents the unique identifier of external
79	 * connectors such as EXTCON_USB, EXTCON_DISP_HDMI and so on. extcon_id
80	 * is necessary to register the extcon device. But, it's not yet
81	 * developed to get the extcon id from device-tree or others.
82	 * On later, it have to be solved.
83	 */
84	if (data->extcon_id > EXTCON_NONE)
85		return -EINVAL;
86
87	data->gpiod = devm_gpiod_get(dev, "extcon", GPIOD_IN);
88	if (IS_ERR(data->gpiod))
89		return PTR_ERR(data->gpiod);
90	irq = gpiod_to_irq(data->gpiod);
91	if (irq <= 0)
92		return irq;
93
94	/*
95	 * It is unlikely that this is an acknowledged interrupt that goes
96	 * away after handling, what we are looking for are falling edges
97	 * if the signal is active low, and rising edges if the signal is
98	 * active high.
99	 */
100	if (gpiod_is_active_low(data->gpiod))
101		irq_flags = IRQF_TRIGGER_FALLING;
102	else
103		irq_flags = IRQF_TRIGGER_RISING;
104
105	/* Allocate the memory of extcon devie and register extcon device */
106	data->edev = devm_extcon_dev_allocate(dev, &data->extcon_id);
107	if (IS_ERR(data->edev)) {
108		dev_err(dev, "failed to allocate extcon device\n");
109		return -ENOMEM;
110	}
111
112	ret = devm_extcon_dev_register(dev, data->edev);
113	if (ret < 0)
114		return ret;
115
116	ret = devm_delayed_work_autocancel(dev, &data->work, gpio_extcon_work);
117	if (ret)
118		return ret;
119
120	/*
121	 * Request the interrupt of gpio to detect whether external connector
122	 * is attached or detached.
123	 */
124	ret = devm_request_any_context_irq(dev, irq,
125					gpio_irq_handler, irq_flags,
126					pdev->name, data);
127	if (ret < 0)
128		return ret;
129
130	platform_set_drvdata(pdev, data);
131	/* Perform initial detection */
132	gpio_extcon_work(&data->work.work);
133
134	return 0;
135}
136
137#ifdef CONFIG_PM_SLEEP
138static int gpio_extcon_resume(struct device *dev)
139{
140	struct gpio_extcon_data *data;
141
142	data = dev_get_drvdata(dev);
143	if (data->check_on_resume)
144		queue_delayed_work(system_power_efficient_wq,
145			&data->work, data->debounce_jiffies);
146
147	return 0;
148}
149#endif
150
151static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume);
152
153static struct platform_driver gpio_extcon_driver = {
154	.probe		= gpio_extcon_probe,
155	.driver		= {
156		.name	= "extcon-gpio",
157		.pm	= &gpio_extcon_pm_ops,
158	},
159};
160
161module_platform_driver(gpio_extcon_driver);
162
163MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
164MODULE_DESCRIPTION("GPIO extcon driver");
165MODULE_LICENSE("GPL");
166