v4.19.13 snapshot.
diff --git a/drivers/extcon/extcon-gpio.c b/drivers/extcon/extcon-gpio.c
new file mode 100644
index 0000000..13ba3a6
--- /dev/null
+++ b/drivers/extcon/extcon-gpio.c
@@ -0,0 +1,171 @@
+/*
+ * 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);
+}
+
+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;
+ 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;
+}
+
+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");