blob: 089dc3b71925e1284ea2d7ba56b02e787b0fa9f5 [file] [log] [blame]
/*
* 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/property.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
/**
* struct gpio_extcon_data - A simple GPIO-controlled extcon device state container.
* @edev: Extcon device.
* @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.
* @connector_type: The connector type we're detecting on this extcon, terminated with EXTCON_NONE
* One GPIO is one cable, so one type only.
* @check_on_resume: Boolean describing whether to check the state of gpio
* while resuming from sleep.
*/
struct gpio_extcon_data {
struct extcon_dev *edev;
struct delayed_work work;
unsigned long debounce_jiffies;
struct gpio_desc *gpiod;
unsigned int connector_type[2];
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->connector_type[0], 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_probe(struct platform_device *pdev)
{
struct gpio_extcon_data *data;
struct device *dev = &pdev->dev;
unsigned long irq_flags;
u32 debounce_usecs;
u32 connector_type;
int irq;
int ret;
data = devm_kzalloc(dev, sizeof(struct gpio_extcon_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
/*
* Always checking connector state on resume makes most sense so do this
* by default.
*
* TODO: if parameterization is needed, augment this to use proper device
* properties or set it up from PM core.
*/
data->check_on_resume = true;
data->gpiod = devm_gpiod_get(dev, "extcon", GPIOD_IN);
if (IS_ERR(data->gpiod))
return PTR_ERR(data->gpiod);
irq = gpiod_to_irq(data->gpiod);
if (irq <= 0)
return irq;
/*
* It is unlikely that this is an acknowledged interrupt that goes
* away after handling, what we are looking for are falling edges
* if the signal is active low, and rising edges if the signal is
* active high.
*/
if (gpiod_is_active_low(data->gpiod))
irq_flags = IRQF_TRIGGER_FALLING;
else
irq_flags = IRQF_TRIGGER_RISING;
ret = device_property_read_u32(dev, "extcon-connector-types", &connector_type);
if (ret || !connector_type) {
dev_err(dev, "illegal cable type or undefined cable type\n");
return -EINVAL;
}
data->connector_type[0] = connector_type;
data->connector_type[1] = EXTCON_NONE;
/* Allocate the memory of extcon devie and register extcon device */
data->edev = devm_extcon_dev_allocate(dev, data->connector_type);
if (IS_ERR(data->edev)) {
dev_err(dev, "failed to allocate extcon device\n");
return -ENOMEM;
}
ret = device_property_read_u32(dev, "input-debounce", &debounce_usecs);
if (ret || !debounce_usecs) {
dev_err(dev, "illegal debounce value, set to 20 ms\n");
debounce_usecs = 20000;
}
ret = gpiod_set_debounce(data->gpiod, debounce_usecs);
if (ret)
data->debounce_jiffies = msecs_to_jiffies(debounce_usecs * 1000);
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, irq,
gpio_irq_handler, 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->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");