drivers/iio/trigger/iio-trig-interrupt.c

/*
 * Industrial I/O - generic interrupt based trigger support
 *
 * Copyright (c) 2008-2013 Jonathan Cameron
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/slab.h>

#include <linux/iio/iio.h>
#include <linux/iio/trigger.h>


struct iio_interrupt_trigger_info {
	unsigned int irq;
};

static irqreturn_t iio_interrupt_trigger_poll(int irq, void *private)
{
	/* Timestamp not currently provided */
	iio_trigger_poll(private, 0);
	return IRQ_HANDLED;
}

static const struct iio_trigger_ops iio_interrupt_trigger_ops = {
	.owner = THIS_MODULE,
};

static int iio_interrupt_trigger_probe(struct platform_device *pdev)
{
	struct iio_interrupt_trigger_info *trig_info;
	struct iio_trigger *trig;
	unsigned long irqflags;
	struct resource *irq_res;
	int irq, ret = 0;

	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

	if (irq_res == NULL)
		return -ENODEV;

	irqflags = (irq_res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;

	irq = irq_res->start;

	trig = iio_trigger_alloc("irqtrig%d", irq);
	if (!trig) {
		ret = -ENOMEM;
		goto error_ret;
	}

	trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
	if (!trig_info) {
		ret = -ENOMEM;
		goto error_put_trigger;
	}
	iio_trigger_set_drvdata(trig, trig_info);
	trig_info->irq = irq;
	trig->ops = &iio_interrupt_trigger_ops;
	ret = request_irq(irq, iio_interrupt_trigger_poll,
			  irqflags, trig->name, trig);
	if (ret) {
		dev_err(&pdev->dev,
			"request IRQ-%d failed", irq);
		goto error_free_trig_info;
	}

	ret = iio_trigger_register(trig);
	if (ret)
		goto error_release_irq;
	platform_set_drvdata(pdev, trig);

	return 0;

/* First clean up the partly allocated trigger */
error_release_irq:
	free_irq(irq, trig);
error_free_trig_info:
	kfree(trig_info);
error_put_trigger:
	iio_trigger_put(trig);
error_ret:
	return ret;
}

static int iio_interrupt_trigger_remove(struct platform_device *pdev)
{
	struct iio_trigger *trig;
	struct iio_interrupt_trigger_info *trig_info;

	trig = platform_get_drvdata(pdev);
	trig_info = iio_trigger_get_drvdata(trig);
	iio_trigger_unregister(trig);
	free_irq(trig_info->irq, trig);
	kfree(trig_info);
	iio_trigger_put(trig);

	return 0;
}

static struct platform_driver iio_interrupt_trigger_driver = {
	.probe = iio_interrupt_trigger_probe,
	.remove = iio_interrupt_trigger_remove,
	.driver = {
		.name = "iio_interrupt_trigger",
		.owner = THIS_MODULE,
	},
};

module_platform_driver(iio_interrupt_trigger_driver);

MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
MODULE_DESCRIPTION("Interrupt trigger for the iio subsystem");
MODULE_LICENSE("GPL v2");