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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 that a fully
* fledged trigger driver.
*
* TODO:
*
* Add board config elements to allow specification of startup settings.
* Add configuration settings (irq type etc)
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include "../iio.h"
#include "../trigger.h"
LIST_HEAD(iio_gpio_trigger_list);
DEFINE_MUTEX(iio_gpio_trigger_list_lock);
struct iio_gpio_trigger_info {
struct mutex in_use;
int gpio;
};
/*
* 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)
{
iio_trigger_poll(private);
return IRQ_HANDLED;
}
static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
static struct attribute *iio_gpio_trigger_attrs[] = {
&dev_attr_name.attr,
NULL,
};
static const struct attribute_group iio_gpio_trigger_attr_group = {
.attrs = iio_gpio_trigger_attrs,
};
static int iio_gpio_trigger_probe(struct platform_device *dev)
{
int *pdata = dev->dev.platform_data;
struct iio_gpio_trigger_info *trig_info;
struct iio_trigger *trig, *trig2;
int i, irq, ret = 0;
if (!pdata) {
printk(KERN_ERR "No IIO gpio trigger platform data found\n");
goto error_ret;
}
for (i = 0;; i++) {
if (!gpio_is_valid(pdata[i]))
break;
trig = iio_allocate_trigger();
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->control_attrs = &iio_gpio_trigger_attr_group;
trig->private_data = trig_info;
trig_info->gpio = pdata[i];
trig->owner = THIS_MODULE;
trig->name = kmalloc(IIO_TRIGGER_NAME_LENGTH, GFP_KERNEL);
if (!trig->name) {
ret = -ENOMEM;
goto error_free_trig_info;
}
snprintf((char *)trig->name,
IIO_TRIGGER_NAME_LENGTH,
"gpiotrig%d",
pdata[i]);
ret = gpio_request(trig_info->gpio, trig->name);
if (ret)
goto error_free_name;
ret = gpio_direction_input(trig_info->gpio);
if (ret)
goto error_release_gpio;
irq = gpio_to_irq(trig_info->gpio);
if (irq < 0) {
ret = irq;
goto error_release_gpio;
}
ret = request_irq(irq, iio_gpio_trigger_poll,
IRQF_TRIGGER_RISING,
trig->name,
trig);
if (ret)
goto error_release_gpio;
ret = iio_trigger_register(trig);
if (ret)
goto error_release_irq;
list_add_tail(&trig->alloc_list, &iio_gpio_trigger_list);
}
return 0;
/* First clean up the partly allocated trigger */
error_release_irq:
free_irq(irq, trig);
error_release_gpio:
gpio_free(trig_info->gpio);
error_free_name:
kfree(trig->name);
error_free_trig_info:
kfree(trig_info);
error_put_trigger:
iio_put_trigger(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->gpio), trig);
gpio_free(trig_info->gpio);
kfree(trig->name);
kfree(trig_info);
iio_trigger_unregister(trig);
}
error_ret:
return ret;
}
static int iio_gpio_trigger_remove(struct platform_device *dev)
{
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(gpio_to_irq(trig_info->gpio), trig);
gpio_free(trig_info->gpio);
kfree(trig->name);
kfree(trig_info);
iio_put_trigger(trig);
}
mutex_unlock(&iio_gpio_trigger_list_lock);
return 0;
}
static struct platform_driver iio_gpio_trigger_driver = {
.probe = iio_gpio_trigger_probe,
.remove = iio_gpio_trigger_remove,
.driver = {
.name = "iio_gpio_trigger",
.owner = THIS_MODULE,
},
};
static int __init iio_gpio_trig_init(void)
{
return platform_driver_register(&iio_gpio_trigger_driver);
}
module_init(iio_gpio_trig_init);
static void __exit iio_gpio_trig_exit(void)
{
platform_driver_unregister(&iio_gpio_trigger_driver);
}
module_exit(iio_gpio_trig_exit);
MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
MODULE_DESCRIPTION("Example gpio trigger for the iio subsystem");
MODULE_LICENSE("GPL v2");
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