1/*
  2 * extcon_gpio.c - Single-state GPIO extcon driver based on extcon class
  3 *
  4 * Copyright (C) 2008 Google, Inc.
  5 * Author: Mike Lockwood <lockwood@android.com>
  6 *
  7 * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
  8 * (originally switch class is supported)
  9 *
 10 * This software is licensed under the terms of the GNU General Public
 11 * License version 2, as published by the Free Software Foundation, and
 12 * may be copied, distributed, and modified under those terms.
 13 *
 14 * This program is distributed in the hope that it will be useful,
 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 17 * GNU General Public License for more details.
 18 */
 19
 20#include <linux/extcon-provider.h>
 21#include <linux/gpio/consumer.h>
 22#include <linux/init.h>
 23#include <linux/interrupt.h>
 24#include <linux/kernel.h>
 25#include <linux/module.h>
 26#include <linux/platform_device.h>
 27#include <linux/slab.h>
 28#include <linux/workqueue.h>
 29
 30/**
 31 * struct gpio_extcon_data - A simple GPIO-controlled extcon device state container.
 32 * @edev:		Extcon device.
 33 * @irq:		Interrupt line for the external connector.
 34 * @work:		Work fired by the interrupt.
 35 * @debounce_jiffies:	Number of jiffies to wait for the GPIO to stabilize, from the debounce
 36 *			value.
 37 * @gpiod:		GPIO descriptor for this external connector.
 38 * @extcon_id:		The unique id of specific external connector.
 39 * @debounce:		Debounce time for GPIO IRQ in ms.
 40 * @irq_flags:		IRQ Flags (e.g., IRQF_TRIGGER_LOW).
 41 * @check_on_resume:	Boolean describing whether to check the state of gpio
 42 *			while resuming from sleep.
 43 */
 44struct gpio_extcon_data {
 45	struct extcon_dev *edev;
 46	int irq;
 47	struct delayed_work work;
 48	unsigned long debounce_jiffies;
 49	struct gpio_desc *gpiod;
 50	unsigned int extcon_id;
 51	unsigned long debounce;
 52	unsigned long irq_flags;
 53	bool check_on_resume;
 54};
 55
 56static void gpio_extcon_work(struct work_struct *work)
 57{
 58	int state;
 59	struct gpio_extcon_data	*data =
 60		container_of(to_delayed_work(work), struct gpio_extcon_data,
 61			     work);
 62
 63	state = gpiod_get_value_cansleep(data->gpiod);
 64	extcon_set_state_sync(data->edev, data->extcon_id, state);
 65}
 66
 67static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
 68{
 69	struct gpio_extcon_data *data = dev_id;
 70
 71	queue_delayed_work(system_power_efficient_wq, &data->work,
 72			      data->debounce_jiffies);
 73	return IRQ_HANDLED;
 74}
 75
 76static int gpio_extcon_probe(struct platform_device *pdev)
 77{
 78	struct gpio_extcon_data *data;
 79	struct device *dev = &pdev->dev;
 80	int ret;
 81
 82	data = devm_kzalloc(dev, sizeof(struct gpio_extcon_data), GFP_KERNEL);
 83	if (!data)
 84		return -ENOMEM;
 85
 86	/*
 87	 * FIXME: extcon_id represents the unique identifier of external
 88	 * connectors such as EXTCON_USB, EXTCON_DISP_HDMI and so on. extcon_id
 89	 * is necessary to register the extcon device. But, it's not yet
 90	 * developed to get the extcon id from device-tree or others.
 91	 * On later, it have to be solved.
 92	 */
 93	if (!data->irq_flags || data->extcon_id > EXTCON_NONE)
 94		return -EINVAL;
 95
 96	data->gpiod = devm_gpiod_get(dev, "extcon", GPIOD_IN);
 97	if (IS_ERR(data->gpiod))
 98		return PTR_ERR(data->gpiod);
 99	data->irq = gpiod_to_irq(data->gpiod);
100	if (data->irq <= 0)
101		return data->irq;
102
103	/* Allocate the memory of extcon devie and register extcon device */
104	data->edev = devm_extcon_dev_allocate(dev, &data->extcon_id);
105	if (IS_ERR(data->edev)) {
106		dev_err(dev, "failed to allocate extcon device\n");
107		return -ENOMEM;
108	}
109
110	ret = devm_extcon_dev_register(dev, data->edev);
111	if (ret < 0)
112		return ret;
113
114	INIT_DELAYED_WORK(&data->work, gpio_extcon_work);
115
116	/*
117	 * Request the interrupt of gpio to detect whether external connector
118	 * is attached or detached.
119	 */
120	ret = devm_request_any_context_irq(dev, data->irq,
121					gpio_irq_handler, data->irq_flags,
122					pdev->name, data);
123	if (ret < 0)
124		return ret;
125
126	platform_set_drvdata(pdev, data);
127	/* Perform initial detection */
128	gpio_extcon_work(&data->work.work);
129
130	return 0;
131}
132
133static int gpio_extcon_remove(struct platform_device *pdev)
134{
135	struct gpio_extcon_data *data = platform_get_drvdata(pdev);
136
137	cancel_delayed_work_sync(&data->work);
138
139	return 0;
140}
141
142#ifdef CONFIG_PM_SLEEP
143static int gpio_extcon_resume(struct device *dev)
144{
145	struct gpio_extcon_data *data;
146
147	data = dev_get_drvdata(dev);
148	if (data->check_on_resume)
149		queue_delayed_work(system_power_efficient_wq,
150			&data->work, data->debounce_jiffies);
151
152	return 0;
153}
154#endif
155
156static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume);
157
158static struct platform_driver gpio_extcon_driver = {
159	.probe		= gpio_extcon_probe,
160	.remove		= gpio_extcon_remove,
161	.driver		= {
162		.name	= "extcon-gpio",
163		.pm	= &gpio_extcon_pm_ops,
164	},
165};
166
167module_platform_driver(gpio_extcon_driver);
168
169MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
170MODULE_DESCRIPTION("GPIO extcon driver");
171MODULE_LICENSE("GPL");