1/*
  2 *  drivers/extcon/extcon_gpio.c
  3 *
  4 *  Single-state GPIO extcon driver based on extcon class
  5 *
  6 * Copyright (C) 2008 Google, Inc.
  7 * Author: Mike Lockwood <lockwood@android.com>
  8 *
  9 * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
 10 * (originally switch class is supported)
 11 *
 12 * This software is licensed under the terms of the GNU General Public
 13 * License version 2, as published by the Free Software Foundation, and
 14 * may be copied, distributed, and modified under those terms.
 15 *
 16 * This program is distributed in the hope that it will be useful,
 17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 19 * GNU General Public License for more details.
 20 *
 21*/
 22
 23#include <linux/module.h>
 24#include <linux/kernel.h>
 25#include <linux/init.h>
 26#include <linux/interrupt.h>
 27#include <linux/platform_device.h>
 28#include <linux/slab.h>
 29#include <linux/workqueue.h>
 30#include <linux/gpio.h>
 31#include <linux/extcon.h>
 32#include <linux/extcon/extcon-gpio.h>
 33
 34struct gpio_extcon_data {
 35	struct extcon_dev edev;
 36	unsigned gpio;
 37	bool gpio_active_low;
 38	const char *state_on;
 39	const char *state_off;
 40	int irq;
 41	struct delayed_work work;
 42	unsigned long debounce_jiffies;
 43	bool check_on_resume;
 44};
 45
 46static void gpio_extcon_work(struct work_struct *work)
 47{
 48	int state;
 49	struct gpio_extcon_data	*data =
 50		container_of(to_delayed_work(work), struct gpio_extcon_data,
 51			     work);
 52
 53	state = gpio_get_value(data->gpio);
 54	if (data->gpio_active_low)
 55		state = !state;
 56	extcon_set_state(&data->edev, state);
 57}
 58
 59static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
 60{
 61	struct gpio_extcon_data *extcon_data = dev_id;
 62
 63	queue_delayed_work(system_power_efficient_wq, &extcon_data->work,
 64			      extcon_data->debounce_jiffies);
 65	return IRQ_HANDLED;
 66}
 67
 68static ssize_t extcon_gpio_print_state(struct extcon_dev *edev, char *buf)
 69{
 70	struct gpio_extcon_data	*extcon_data =
 71		container_of(edev, struct gpio_extcon_data, edev);
 72	const char *state;
 73	if (extcon_get_state(edev))
 74		state = extcon_data->state_on;
 75	else
 76		state = extcon_data->state_off;
 77
 78	if (state)
 79		return sprintf(buf, "%s\n", state);
 80	return -EINVAL;
 81}
 82
 83static int gpio_extcon_probe(struct platform_device *pdev)
 84{
 85	struct gpio_extcon_platform_data *pdata = dev_get_platdata(&pdev->dev);
 86	struct gpio_extcon_data *extcon_data;
 87	int ret;
 88
 89	if (!pdata)
 90		return -EBUSY;
 91	if (!pdata->irq_flags) {
 92		dev_err(&pdev->dev, "IRQ flag is not specified.\n");
 93		return -EINVAL;
 94	}
 95
 96	extcon_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data),
 97				   GFP_KERNEL);
 98	if (!extcon_data)
 99		return -ENOMEM;
100
101	extcon_data->edev.name = pdata->name;
102	extcon_data->edev.dev.parent = &pdev->dev;
103	extcon_data->gpio = pdata->gpio;
104	extcon_data->gpio_active_low = pdata->gpio_active_low;
105	extcon_data->state_on = pdata->state_on;
106	extcon_data->state_off = pdata->state_off;
107	extcon_data->check_on_resume = pdata->check_on_resume;
108	if (pdata->state_on && pdata->state_off)
109		extcon_data->edev.print_state = extcon_gpio_print_state;
110
111	ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN,
112				    pdev->name);
113	if (ret < 0)
114		return ret;
115
116	if (pdata->debounce) {
117		ret = gpio_set_debounce(extcon_data->gpio,
118					pdata->debounce * 1000);
119		if (ret < 0)
120			extcon_data->debounce_jiffies =
121				msecs_to_jiffies(pdata->debounce);
122	}
123
124	ret = extcon_dev_register(&extcon_data->edev);
125	if (ret < 0)
126		return ret;
127
128	INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work);
129
130	extcon_data->irq = gpio_to_irq(extcon_data->gpio);
131	if (extcon_data->irq < 0) {
132		ret = extcon_data->irq;
133		goto err;
134	}
135
136	ret = request_any_context_irq(extcon_data->irq, gpio_irq_handler,
137				      pdata->irq_flags, pdev->name,
138				      extcon_data);
139	if (ret < 0)
140		goto err;
141
142	platform_set_drvdata(pdev, extcon_data);
143	/* Perform initial detection */
144	gpio_extcon_work(&extcon_data->work.work);
145
146	return 0;
147
148err:
149	extcon_dev_unregister(&extcon_data->edev);
150
151	return ret;
152}
153
154static int gpio_extcon_remove(struct platform_device *pdev)
155{
156	struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev);
157
158	cancel_delayed_work_sync(&extcon_data->work);
159	free_irq(extcon_data->irq, extcon_data);
160	extcon_dev_unregister(&extcon_data->edev);
161
162	return 0;
163}
164
165#ifdef CONFIG_PM_SLEEP
166static int gpio_extcon_resume(struct device *dev)
167{
168	struct gpio_extcon_data *extcon_data;
169
170	extcon_data = dev_get_drvdata(dev);
171	if (extcon_data->check_on_resume)
172		queue_delayed_work(system_power_efficient_wq,
173			&extcon_data->work, extcon_data->debounce_jiffies);
174
175	return 0;
176}
177#endif
178
179static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume);
180
181static struct platform_driver gpio_extcon_driver = {
182	.probe		= gpio_extcon_probe,
183	.remove		= gpio_extcon_remove,
184	.driver		= {
185		.name	= "extcon-gpio",
186		.owner	= THIS_MODULE,
187		.pm	= &gpio_extcon_pm_ops,
188	},
189};
190
191module_platform_driver(gpio_extcon_driver);
192
193MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
194MODULE_DESCRIPTION("GPIO extcon driver");
195MODULE_LICENSE("GPL");