172 lines
4.7 KiB
C
172 lines
4.7 KiB
C
/*
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* extcon_gpio.c - Single-state GPIO extcon driver based on extcon class
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*
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* Copyright (C) 2008 Google, Inc.
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* Author: Mike Lockwood <lockwood@android.com>
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*
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* Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
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* (originally switch class is supported)
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/extcon-provider.h>
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#include <linux/gpio/consumer.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/workqueue.h>
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/**
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* struct gpio_extcon_data - A simple GPIO-controlled extcon device state container.
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* @edev: Extcon device.
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* @irq: Interrupt line for the external connector.
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* @work: Work fired by the interrupt.
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* @debounce_jiffies: Number of jiffies to wait for the GPIO to stabilize, from the debounce
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* value.
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* @gpiod: GPIO descriptor for this external connector.
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* @extcon_id: The unique id of specific external connector.
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* @debounce: Debounce time for GPIO IRQ in ms.
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* @irq_flags: IRQ Flags (e.g., IRQF_TRIGGER_LOW).
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* @check_on_resume: Boolean describing whether to check the state of gpio
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* while resuming from sleep.
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*/
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struct gpio_extcon_data {
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struct extcon_dev *edev;
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int irq;
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struct delayed_work work;
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unsigned long debounce_jiffies;
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struct gpio_desc *gpiod;
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unsigned int extcon_id;
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unsigned long debounce;
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unsigned long irq_flags;
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bool check_on_resume;
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};
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static void gpio_extcon_work(struct work_struct *work)
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{
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int state;
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struct gpio_extcon_data *data =
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container_of(to_delayed_work(work), struct gpio_extcon_data,
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work);
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state = gpiod_get_value_cansleep(data->gpiod);
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extcon_set_state_sync(data->edev, data->extcon_id, state);
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}
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static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
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{
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struct gpio_extcon_data *data = dev_id;
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queue_delayed_work(system_power_efficient_wq, &data->work,
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data->debounce_jiffies);
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return IRQ_HANDLED;
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}
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static int gpio_extcon_probe(struct platform_device *pdev)
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{
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struct gpio_extcon_data *data;
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struct device *dev = &pdev->dev;
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int ret;
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data = devm_kzalloc(dev, sizeof(struct gpio_extcon_data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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/*
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* FIXME: extcon_id represents the unique identifier of external
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* connectors such as EXTCON_USB, EXTCON_DISP_HDMI and so on. extcon_id
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* is necessary to register the extcon device. But, it's not yet
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* developed to get the extcon id from device-tree or others.
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* On later, it have to be solved.
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*/
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if (!data->irq_flags || data->extcon_id > EXTCON_NONE)
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return -EINVAL;
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data->gpiod = devm_gpiod_get(dev, "extcon", GPIOD_IN);
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if (IS_ERR(data->gpiod))
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return PTR_ERR(data->gpiod);
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data->irq = gpiod_to_irq(data->gpiod);
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if (data->irq <= 0)
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return data->irq;
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/* Allocate the memory of extcon devie and register extcon device */
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data->edev = devm_extcon_dev_allocate(dev, &data->extcon_id);
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if (IS_ERR(data->edev)) {
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dev_err(dev, "failed to allocate extcon device\n");
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return -ENOMEM;
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}
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ret = devm_extcon_dev_register(dev, data->edev);
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if (ret < 0)
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return ret;
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INIT_DELAYED_WORK(&data->work, gpio_extcon_work);
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/*
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* Request the interrupt of gpio to detect whether external connector
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* is attached or detached.
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*/
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ret = devm_request_any_context_irq(dev, data->irq,
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gpio_irq_handler, data->irq_flags,
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pdev->name, data);
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if (ret < 0)
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return ret;
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platform_set_drvdata(pdev, data);
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/* Perform initial detection */
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gpio_extcon_work(&data->work.work);
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return 0;
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}
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static int gpio_extcon_remove(struct platform_device *pdev)
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{
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struct gpio_extcon_data *data = platform_get_drvdata(pdev);
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cancel_delayed_work_sync(&data->work);
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return 0;
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}
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#ifdef CONFIG_PM_SLEEP
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static int gpio_extcon_resume(struct device *dev)
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{
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struct gpio_extcon_data *data;
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data = dev_get_drvdata(dev);
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if (data->check_on_resume)
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queue_delayed_work(system_power_efficient_wq,
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&data->work, data->debounce_jiffies);
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return 0;
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}
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#endif
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static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume);
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static struct platform_driver gpio_extcon_driver = {
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.probe = gpio_extcon_probe,
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.remove = gpio_extcon_remove,
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.driver = {
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.name = "extcon-gpio",
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.pm = &gpio_extcon_pm_ops,
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},
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};
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module_platform_driver(gpio_extcon_driver);
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MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
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MODULE_DESCRIPTION("GPIO extcon driver");
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MODULE_LICENSE("GPL");
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