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/*
* 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.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_pdata - A simple GPIO-controlled extcon device.
* @extcon_id: The unique id of specific external connector.
* @gpio: Corresponding GPIO.
* @gpio_active_low: Boolean describing whether gpio active state is 1 or 0
* If true, low state of gpio means active.
* If false, high state of gpio means active.
* @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_pdata {
unsigned int extcon_id;
unsigned gpio;
bool gpio_active_low;
unsigned long debounce;
unsigned long irq_flags;
bool check_on_resume;
};
struct gpio_extcon_data {
struct extcon_dev *edev;
int irq;
struct delayed_work work;
unsigned long debounce_jiffies;
struct gpio_desc *id_gpiod;
struct gpio_extcon_pdata *pdata;
};
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->id_gpiod);
if (data->pdata->gpio_active_low)
state = !state;
extcon_set_state_sync(data->edev, data->pdata->extcon_id, state);
}
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;
}
static int gpio_extcon_init(struct device *dev, struct gpio_extcon_data *data)
{
struct gpio_extcon_pdata *pdata = data->pdata;
int ret;
ret = devm_gpio_request_one(dev, pdata->gpio, GPIOF_DIR_IN,
dev_name(dev));
if (ret < 0)
return ret;
data->id_gpiod = gpio_to_desc(pdata->gpio);
if (!data->id_gpiod)
return -EINVAL;
if (pdata->debounce) {
ret = gpiod_set_debounce(data->id_gpiod,
pdata->debounce * 1000);
if (ret < 0)
data->debounce_jiffies =
msecs_to_jiffies(pdata->debounce);
}
data->irq = gpiod_to_irq(data->id_gpiod);
if (data->irq < 0)
return data->irq;
return 0;
}
static int gpio_extcon_probe(struct platform_device *pdev)
{
struct gpio_extcon_pdata *pdata = dev_get_platdata(&pdev->dev);
struct gpio_extcon_data *data;
int ret;
if (!pdata)
return -EBUSY;
if (!pdata->irq_flags || pdata->extcon_id > EXTCON_NONE)
return -EINVAL;
data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
data->pdata = pdata;
/* Initialize the gpio */
ret = gpio_extcon_init(&pdev->dev, data);
if (ret < 0)
return ret;
/* Allocate the memory of extcon devie and register extcon device */
data->edev = devm_extcon_dev_allocate(&pdev->dev, &pdata->extcon_id);
if (IS_ERR(data->edev)) {
dev_err(&pdev->dev, "failed to allocate extcon device\n");
return -ENOMEM;
}
ret = devm_extcon_dev_register(&pdev->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(&pdev->dev, data->irq,
gpio_irq_handler, pdata->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;
}
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;
}
#ifdef CONFIG_PM_SLEEP
static int gpio_extcon_resume(struct device *dev)
{
struct gpio_extcon_data *data;
data = dev_get_drvdata(dev);
if (data->pdata->check_on_resume)
queue_delayed_work(system_power_efficient_wq,
&data->work, data->debounce_jiffies);
return 0;
}
#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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