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/*
* Industrial I/O - gpio based trigger support
*
* Copyright (c) 2008 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.
*
* Currently this is more of a functioning proof of concept than a full
* fledged trigger driver.
*
* TODO:
*
* Add board config elements to allow specification of startup settings.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/iio/iio.h>
#include <linux/iio/trigger.h>
static LIST_HEAD(iio_gpio_trigger_list);
static DEFINE_MUTEX(iio_gpio_trigger_list_lock);
struct iio_gpio_trigger_info {
struct mutex in_use;
unsigned int irq;
};
/*
* Need to reference count these triggers and only enable gpio interrupts
* as appropriate.
*/
/* So what functionality do we want in here?... */
/* set high / low as interrupt type? */
static irqreturn_t iio_gpio_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_gpio_trigger_ops = {
.owner = THIS_MODULE,
};
static int __devinit iio_gpio_trigger_probe(struct platform_device *pdev)
{
struct iio_gpio_trigger_info *trig_info;
struct iio_trigger *trig, *trig2;
unsigned long irqflags;
struct resource *irq_res;
int irq, ret = 0, irq_res_cnt = 0;
do {
irq_res = platform_get_resource(pdev,
IORESOURCE_IRQ, irq_res_cnt);
if (irq_res == NULL) {
if (irq_res_cnt == 0)
dev_err(&pdev->dev, "No GPIO IRQs specified");
break;
}
irqflags = (irq_res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
for (irq = irq_res->start; irq <= irq_res->end; irq++) {
trig = iio_trigger_alloc("irqtrig%d", irq);
if (!trig) {
ret = -ENOMEM;
goto error_free_completed_registrations;
}
trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
if (!trig_info) {
ret = -ENOMEM;
goto error_put_trigger;
}
trig->private_data = trig_info;
trig_info->irq = irq;
trig->ops = &iio_gpio_trigger_ops;
ret = request_irq(irq, iio_gpio_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;
list_add_tail(&trig->alloc_list,
&iio_gpio_trigger_list);
}
irq_res_cnt++;
} while (irq_res != NULL);
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_free_completed_registrations:
/* The rest should have been added to the iio_gpio_trigger_list */
list_for_each_entry_safe(trig,
trig2,
&iio_gpio_trigger_list,
alloc_list) {
trig_info = trig->private_data;
free_irq(gpio_to_irq(trig_info->irq), trig);
kfree(trig_info);
iio_trigger_unregister(trig);
}
return ret;
}
static int __devexit iio_gpio_trigger_remove(struct platform_device *pdev)
{
struct iio_trigger *trig, *trig2;
struct iio_gpio_trigger_info *trig_info;
mutex_lock(&iio_gpio_trigger_list_lock);
list_for_each_entry_safe(trig,
trig2,
&iio_gpio_trigger_list,
alloc_list) {
trig_info = trig->private_data;
iio_trigger_unregister(trig);
free_irq(trig_info->irq, trig);
kfree(trig_info);
iio_trigger_put(trig);
}
mutex_unlock(&iio_gpio_trigger_list_lock);
return 0;
}
static struct platform_driver iio_gpio_trigger_driver = {
.probe = iio_gpio_trigger_probe,
.remove = __devexit_p(iio_gpio_trigger_remove),
.driver = {
.name = "iio_gpio_trigger",
.owner = THIS_MODULE,
},
};
module_platform_driver(iio_gpio_trigger_driver);
MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
MODULE_DESCRIPTION("Example gpio trigger for the iio subsystem");
MODULE_LICENSE("GPL v2");
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