Release 4.17 drivers/extcon/extcon-gpio.c

/*
 * extcon_gpio.c - Single-state GPIO extcon driver based on extcon class
 *
 * Copyright (C) 2008 Google, Inc.
 * Author: Mike Lockwood <lockwood@android.com>
 *
 * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
 * (originally switch class is supported)
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/extcon-provider.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/workqueue.h>

/**
 * struct gpio_extcon_data - A simple GPIO-controlled extcon device state container.
 * @edev:               Extcon device.
 * @irq:                Interrupt line for the external connector.
 * @work:               Work fired by the interrupt.
 * @debounce_jiffies:   Number of jiffies to wait for the GPIO to stabilize, from the debounce
 *                      value.
 * @gpiod:              GPIO descriptor for this external connector.
 * @extcon_id:          The unique id of specific external connector.
 * @debounce:           Debounce time for GPIO IRQ in ms.
 * @irq_flags:          IRQ Flags (e.g., IRQF_TRIGGER_LOW).
 * @check_on_resume:    Boolean describing whether to check the state of gpio
 *                      while resuming from sleep.
 */

struct gpio_extcon_data {
	
struct extcon_dev *edev;
	
int irq;
	
struct delayed_work work;
	
unsigned long debounce_jiffies;
	
struct gpio_desc *gpiod;
	
unsigned int extcon_id;
	
unsigned long debounce;
	
unsigned long irq_flags;
	
bool check_on_resume;
};



static void gpio_extcon_work(struct work_struct *work)
{
	int state;
	struct gpio_extcon_data	*data =
		container_of(to_delayed_work(work), struct gpio_extcon_data,
			     work);

	state = gpiod_get_value_cansleep(data->gpiod);
	extcon_set_state_sync(data->edev, data->extcon_id, state);
}

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47
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Chanwoo Choi
6
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3
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Linus Walleij
1
1.85%
1
20.00%
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54
100.00%
5
100.00%



static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
{
	struct gpio_extcon_data *data = dev_id;

	queue_delayed_work(system_power_efficient_wq, &data->work,
			      data->debounce_jiffies);
	return IRQ_HANDLED;
}

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MyungJoo Ham
31
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3
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1
33.33%
Mark Brown
3
8.11%
1
33.33%
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37
100.00%
3
100.00%



static int gpio_extcon_probe(struct platform_device *pdev)
{
	struct gpio_extcon_data *data;
	struct device *dev = &pdev->dev;
	int ret;

	data = devm_kzalloc(dev, sizeof(struct gpio_extcon_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	/*
         * FIXME: extcon_id represents the unique identifier of external
         * connectors such as EXTCON_USB, EXTCON_DISP_HDMI and so on. extcon_id
         * is necessary to register the extcon device. But, it's not yet
         * developed to get the extcon id from device-tree or others.
         * On later, it have to be solved.
         */
	if (!data->irq_flags || data->extcon_id > EXTCON_NONE)
		return -EINVAL;

	data->gpiod = devm_gpiod_get(dev, "extcon", GPIOD_IN);
	if (IS_ERR(data->gpiod))
		return PTR_ERR(data->gpiod);
	data->irq = gpiod_to_irq(data->gpiod);
	if (data->irq <= 0)
		return data->irq;

	/* Allocate the memory of extcon devie and register extcon device */
	data->edev = devm_extcon_dev_allocate(dev, &data->extcon_id);
	if (IS_ERR(data->edev)) {
		dev_err(dev, "failed to allocate extcon device\n");
		return -ENOMEM;
	}

	ret = devm_extcon_dev_register(dev, data->edev);
	if (ret < 0)
		return ret;

	INIT_DELAYED_WORK(&data->work, gpio_extcon_work);

	/*
         * Request the interrupt of gpio to detect whether external connector
         * is attached or detached.
         */
	ret = devm_request_any_context_irq(dev, data->irq,
					gpio_irq_handler, data->irq_flags,
					pdev->name, data);
	if (ret < 0)
		return ret;

	platform_set_drvdata(pdev, data);
	/* Perform initial detection */
	gpio_extcon_work(&data->work.work);

	return 0;
}

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69
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2
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Chanwoo Choi
36
14.63%
3
25.00%
Guenter Roeck
22
8.94%
2
16.67%
Axel Lin
9
3.66%
2
16.67%
Sangjung Woo
6
2.44%
1
8.33%
Moritz Fischer
1
0.41%
1
8.33%
Total
246
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12
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static int gpio_extcon_remove(struct platform_device *pdev)
{
	struct gpio_extcon_data *data = platform_get_drvdata(pdev);

	cancel_delayed_work_sync(&data->work);

	return 0;
}

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2
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#ifdef CONFIG_PM_SLEEP


static int gpio_extcon_resume(struct device *dev)
{
	struct gpio_extcon_data *data;

	data = dev_get_drvdata(dev);
	if (data->check_on_resume)
		queue_delayed_work(system_power_efficient_wq,
			&data->work, data->debounce_jiffies);

	return 0;
}
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#endif

static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume);


static struct platform_driver gpio_extcon_driver = {
	.probe		= gpio_extcon_probe,
	.remove		= gpio_extcon_remove,
	.driver		= {
		.name	= "extcon-gpio",
		.pm	= &gpio_extcon_pm_ops,
        },
};

module_platform_driver(gpio_extcon_driver);

MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
MODULE_DESCRIPTION("GPIO extcon driver");
MODULE_LICENSE("GPL");
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294
53.16%
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4.55%
Linus Walleij
86
15.55%
2
9.09%
Chanwoo Choi
63
11.39%
8
36.36%
Rongjun Ying
54
9.76%
1
4.55%
Guenter Roeck
22
3.98%
2
9.09%
Axel Lin
9
1.63%
2
9.09%
George Cherian
7
1.27%
1
4.55%
Jingoo Han
6
1.08%
1
4.55%
Sangjung Woo
6
1.08%
1
4.55%
Mark Brown
3
0.54%
1
4.55%
H Hartley Sweeten
2
0.36%
1
4.55%
Moritz Fischer
1
0.18%
1
4.55%
Total
553
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Directory: drivers/extcon

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