Initial import

1 files changed, 192 insertions, 0 deletions

diff --git a/drivers/extcon/extcon-gpio.c b/drivers/extcon/extcon-gpio.c
new file mode 100644
index 000000000..7af33fc43
--- /dev/null
+++ b/drivers/extcon/extcon-gpio.c
@@ -0,0 +1,192 @@
+/*
+ *  drivers/extcon/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.h>
+#include <linux/extcon/extcon-gpio.h>
+#include <linux/gpio.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 {
+	struct extcon_dev *edev;
+	unsigned gpio;
+	bool gpio_active_low;
+	const char *state_on;
+	const char *state_off;
+	int irq;
+	struct delayed_work work;
+	unsigned long debounce_jiffies;
+	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 = gpio_get_value(data->gpio);
+	if (data->gpio_active_low)
+		state = !state;
+	extcon_set_state(data->edev, state);
+}
+
+static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
+{
+	struct gpio_extcon_data *extcon_data = dev_id;
+
+	queue_delayed_work(system_power_efficient_wq, &extcon_data->work,
+			      extcon_data->debounce_jiffies);
+	return IRQ_HANDLED;
+}
+
+static ssize_t extcon_gpio_print_state(struct extcon_dev *edev, char *buf)
+{
+	struct device *dev = edev->dev.parent;
+	struct gpio_extcon_data *extcon_data = dev_get_drvdata(dev);
+	const char *state;
+
+	if (extcon_get_state(edev))
+		state = extcon_data->state_on;
+	else
+		state = extcon_data->state_off;
+
+	if (state)
+		return sprintf(buf, "%s\n", state);
+	return -EINVAL;
+}
+
+static int gpio_extcon_probe(struct platform_device *pdev)
+{
+	struct gpio_extcon_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct gpio_extcon_data *extcon_data;
+	int ret;
+
+	if (!pdata)
+		return -EBUSY;
+	if (!pdata->irq_flags) {
+		dev_err(&pdev->dev, "IRQ flag is not specified.\n");
+		return -EINVAL;
+	}
+
+	extcon_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data),
+				   GFP_KERNEL);
+	if (!extcon_data)
+		return -ENOMEM;
+
+	extcon_data->edev = devm_extcon_dev_allocate(&pdev->dev, NULL);
+	if (IS_ERR(extcon_data->edev)) {
+		dev_err(&pdev->dev, "failed to allocate extcon device\n");
+		return -ENOMEM;
+	}
+	extcon_data->edev->name = pdata->name;
+
+	extcon_data->gpio = pdata->gpio;
+	extcon_data->gpio_active_low = pdata->gpio_active_low;
+	extcon_data->state_on = pdata->state_on;
+	extcon_data->state_off = pdata->state_off;
+	extcon_data->check_on_resume = pdata->check_on_resume;
+	if (pdata->state_on && pdata->state_off)
+		extcon_data->edev->print_state = extcon_gpio_print_state;
+
+	ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN,
+				    pdev->name);
+	if (ret < 0)
+		return ret;
+
+	if (pdata->debounce) {
+		ret = gpio_set_debounce(extcon_data->gpio,
+					pdata->debounce * 1000);
+		if (ret < 0)
+			extcon_data->debounce_jiffies =
+				msecs_to_jiffies(pdata->debounce);
+	}
+
+	ret = devm_extcon_dev_register(&pdev->dev, extcon_data->edev);
+	if (ret < 0)
+		return ret;
+
+	INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work);
+
+	extcon_data->irq = gpio_to_irq(extcon_data->gpio);
+	if (extcon_data->irq < 0)
+		return extcon_data->irq;
+
+	ret = request_any_context_irq(extcon_data->irq, gpio_irq_handler,
+				      pdata->irq_flags, pdev->name,
+				      extcon_data);
+	if (ret < 0)
+		return ret;
+
+	platform_set_drvdata(pdev, extcon_data);
+	/* Perform initial detection */
+	gpio_extcon_work(&extcon_data->work.work);
+
+	return 0;
+}
+
+static int gpio_extcon_remove(struct platform_device *pdev)
+{
+	struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev);
+
+	cancel_delayed_work_sync(&extcon_data->work);
+	free_irq(extcon_data->irq, extcon_data);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int gpio_extcon_resume(struct device *dev)
+{
+	struct gpio_extcon_data *extcon_data;
+
+	extcon_data = dev_get_drvdata(dev);
+	if (extcon_data->check_on_resume)
+		queue_delayed_work(system_power_efficient_wq,
+			&extcon_data->work, extcon_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");