/*
 * Example stub i2c driver
 *
 * Copyright (c) 2015 Red Hat Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Red Hat authors:
 * Hans de Goede <hdegoede@redhat.com>
 */

#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of.h>

struct stub_data {
	struct i2c_client *client;
	struct gpio_desc *wake_gpio;
	/* Add driver data here */
};

static irqreturn_t stub_irq(int irq, void *dev_id)
{
	struct stub_data *data = dev_id;
	struct device *dev = &data->client->dev;

	dev_info(dev, "OOB interrupt triggered\n");

	return IRQ_HANDLED;
}

static void stub_start(struct stub_data *data)
{
	enable_irq(data->client->irq);
	gpiod_set_value_cansleep(data->wake_gpio, 1);
}

static void stub_stop(struct stub_data *data)
{
	disable_irq(data->client->irq);
	gpiod_set_value_cansleep(data->wake_gpio, 0);
}

#ifdef CONFIG_PM_SLEEP
static int stub_suspend(struct device *dev)
{
	struct stub_data *data = i2c_get_clientdata(to_i2c_client(dev));

	stub_stop(data);

	return 0;
}

static int stub_resume(struct device *dev)
{
	struct stub_data *data = i2c_get_clientdata(to_i2c_client(dev));

	stub_start(data);

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(stub_pm_ops, stub_suspend, stub_resume);

static int stub_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct device *dev = &client->dev;
	struct stub_data *data;
	int error;

	if (!client->irq) {
		dev_err(dev, "Error no irq specified\n");
		return -EINVAL;
	}

	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->wake_gpio = devm_gpiod_get(dev, "wake", GPIOD_OUT_LOW);
	if (IS_ERR(data->wake_gpio)) {
		error = PTR_ERR(data->wake_gpio);
		if (error != -EPROBE_DEFER)
			dev_err(dev, "Error getting wake gpio: %d\n", error);
		return error;
	}

	data->client = client;

	error = devm_request_threaded_irq(dev, client->irq, NULL, stub_irq,
					  IRQF_ONESHOT, client->name, data);
	if (error) {
		dev_err(dev, "Error requesting irq: %d\n", error);
		return error;
	}

	i2c_set_clientdata(client, data);

	dev_info(dev, "Stub i2c device Stub Model successfully initialized\n");

	return 0;
}

static const struct of_device_id stub_of_match[] = {
	{ .compatible = "stub,stub-model" },
	{ }
};
MODULE_DEVICE_TABLE(of, stub_of_match);

/* This is useless for OF-enabled devices, but it is needed by I2C subsystem */
static const struct i2c_device_id stub_i2c_id[] = {
	{ },
};
MODULE_DEVICE_TABLE(i2c, stub_i2c_id);

static struct i2c_driver stub_driver = {
	.driver = {
		.owner	= THIS_MODULE,
		.name	= "stub_stub_model",
		.pm	= &stub_pm_ops,
		.of_match_table = stub_of_match,
	},
	.probe = stub_probe,
	.id_table = stub_i2c_id,
};

module_i2c_driver(stub_driver);

MODULE_DESCRIPTION("Basic stub I2C driver");
MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
MODULE_LICENSE("GPL");