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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * extcon_gpio.c - Single-state GPIO extcon driver based on extcon class4 *5 * Copyright (C) 2008 Google, Inc.6 * Author: Mike Lockwood <lockwood@android.com>7 *8 * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon9 * (originally switch class is supported)10 */11 12#include <linux/devm-helpers.h>13#include <linux/extcon-provider.h>14#include <linux/gpio/consumer.h>15#include <linux/init.h>16#include <linux/interrupt.h>17#include <linux/kernel.h>18#include <linux/module.h>19#include <linux/platform_device.h>20#include <linux/slab.h>21#include <linux/workqueue.h>22 23/**24 * struct gpio_extcon_data - A simple GPIO-controlled extcon device state container.25 * @edev: Extcon device.26 * @work: Work fired by the interrupt.27 * @debounce_jiffies: Number of jiffies to wait for the GPIO to stabilize, from the debounce28 * value.29 * @gpiod: GPIO descriptor for this external connector.30 * @extcon_id: The unique id of specific external connector.31 * @debounce: Debounce time for GPIO IRQ in ms.32 * @check_on_resume: Boolean describing whether to check the state of gpio33 * while resuming from sleep.34 */35struct gpio_extcon_data {36 struct extcon_dev *edev;37 struct delayed_work work;38 unsigned long debounce_jiffies;39 struct gpio_desc *gpiod;40 unsigned int extcon_id;41 unsigned long debounce;42 bool check_on_resume;43};44 45static void gpio_extcon_work(struct work_struct *work)46{47 int state;48 struct gpio_extcon_data *data =49 container_of(to_delayed_work(work), struct gpio_extcon_data,50 work);51 52 state = gpiod_get_value_cansleep(data->gpiod);53 extcon_set_state_sync(data->edev, data->extcon_id, state);54}55 56static irqreturn_t gpio_irq_handler(int irq, void *dev_id)57{58 struct gpio_extcon_data *data = dev_id;59 60 queue_delayed_work(system_power_efficient_wq, &data->work,61 data->debounce_jiffies);62 return IRQ_HANDLED;63}64 65static int gpio_extcon_probe(struct platform_device *pdev)66{67 struct gpio_extcon_data *data;68 struct device *dev = &pdev->dev;69 unsigned long irq_flags;70 int irq;71 int ret;72 73 data = devm_kzalloc(dev, sizeof(struct gpio_extcon_data), GFP_KERNEL);74 if (!data)75 return -ENOMEM;76 77 /*78 * FIXME: extcon_id represents the unique identifier of external79 * connectors such as EXTCON_USB, EXTCON_DISP_HDMI and so on. extcon_id80 * is necessary to register the extcon device. But, it's not yet81 * developed to get the extcon id from device-tree or others.82 * On later, it have to be solved.83 */84 if (data->extcon_id > EXTCON_NONE)85 return -EINVAL;86 87 data->gpiod = devm_gpiod_get(dev, "extcon", GPIOD_IN);88 if (IS_ERR(data->gpiod))89 return PTR_ERR(data->gpiod);90 irq = gpiod_to_irq(data->gpiod);91 if (irq <= 0)92 return irq;93 94 /*95 * It is unlikely that this is an acknowledged interrupt that goes96 * away after handling, what we are looking for are falling edges97 * if the signal is active low, and rising edges if the signal is98 * active high.99 */100 if (gpiod_is_active_low(data->gpiod))101 irq_flags = IRQF_TRIGGER_FALLING;102 else103 irq_flags = IRQF_TRIGGER_RISING;104 105 /* Allocate the memory of extcon devie and register extcon device */106 data->edev = devm_extcon_dev_allocate(dev, &data->extcon_id);107 if (IS_ERR(data->edev)) {108 dev_err(dev, "failed to allocate extcon device\n");109 return -ENOMEM;110 }111 112 ret = devm_extcon_dev_register(dev, data->edev);113 if (ret < 0)114 return ret;115 116 ret = devm_delayed_work_autocancel(dev, &data->work, gpio_extcon_work);117 if (ret)118 return ret;119 120 /*121 * Request the interrupt of gpio to detect whether external connector122 * is attached or detached.123 */124 ret = devm_request_any_context_irq(dev, irq,125 gpio_irq_handler, irq_flags,126 pdev->name, data);127 if (ret < 0)128 return ret;129 130 platform_set_drvdata(pdev, data);131 /* Perform initial detection */132 gpio_extcon_work(&data->work.work);133 134 return 0;135}136 137#ifdef CONFIG_PM_SLEEP138static int gpio_extcon_resume(struct device *dev)139{140 struct gpio_extcon_data *data;141 142 data = dev_get_drvdata(dev);143 if (data->check_on_resume)144 queue_delayed_work(system_power_efficient_wq,145 &data->work, data->debounce_jiffies);146 147 return 0;148}149#endif150 151static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume);152 153static struct platform_driver gpio_extcon_driver = {154 .probe = gpio_extcon_probe,155 .driver = {156 .name = "extcon-gpio",157 .pm = &gpio_extcon_pm_ops,158 },159};160 161module_platform_driver(gpio_extcon_driver);162 163MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");164MODULE_DESCRIPTION("GPIO extcon driver");165MODULE_LICENSE("GPL");166