2 * Industrial I/O - gpio based trigger support
4 * Copyright (c) 2008 Jonathan Cameron
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
10 * Currently this is more of a functioning proof of concept that a fully
11 * fledged trigger driver.
15 * Add board config elements to allow specification of startup settings.
16 * Add configuration settings (irq type etc)
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/platform_device.h>
22 #include <linux/interrupt.h>
23 #include <linux/gpio.h>
24 #include <linux/slab.h>
27 #include "../trigger.h"
29 LIST_HEAD(iio_gpio_trigger_list);
30 DEFINE_MUTEX(iio_gpio_trigger_list_lock);
32 struct iio_gpio_trigger_info {
37 * Need to reference count these triggers and only enable gpio interrupts
41 /* So what functionality do we want in here?... */
42 /* set high / low as interrupt type? */
44 static irqreturn_t iio_gpio_trigger_poll(int irq, void *private)
46 iio_trigger_poll(private);
50 static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
52 static struct attribute *iio_gpio_trigger_attrs[] = {
57 static const struct attribute_group iio_gpio_trigger_attr_group = {
58 .attrs = iio_gpio_trigger_attrs,
61 static int iio_gpio_trigger_probe(struct platform_device *dev)
63 int *pdata = dev->dev.platform_data;
64 struct iio_gpio_trigger_info *trig_info;
65 struct iio_trigger *trig, *trig2;
68 printk(KERN_ERR "No IIO gpio trigger platform data found\n");
72 if (!gpio_is_valid(pdata[i]))
74 trig = iio_allocate_trigger();
77 goto error_free_completed_registrations;
80 trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
83 goto error_put_trigger;
85 trig->control_attrs = &iio_gpio_trigger_attr_group;
86 trig->private_data = trig_info;
87 trig_info->gpio = pdata[i];
88 trig->owner = THIS_MODULE;
89 trig->name = kmalloc(IIO_TRIGGER_NAME_LENGTH, GFP_KERNEL);
92 goto error_free_trig_info;
94 snprintf((char *)trig->name,
95 IIO_TRIGGER_NAME_LENGTH,
98 ret = gpio_request(trig_info->gpio, trig->name);
100 goto error_free_name;
102 ret = gpio_direction_input(trig_info->gpio);
104 goto error_release_gpio;
106 irq = gpio_to_irq(trig_info->gpio);
109 goto error_release_gpio;
112 ret = request_irq(irq, iio_gpio_trigger_poll,
117 goto error_release_gpio;
119 ret = iio_trigger_register(trig);
121 goto error_release_irq;
123 list_add_tail(&trig->alloc_list, &iio_gpio_trigger_list);
128 /* First clean up the partly allocated trigger */
132 gpio_free(trig_info->gpio);
135 error_free_trig_info:
138 iio_put_trigger(trig);
139 error_free_completed_registrations:
140 /* The rest should have been added to the iio_gpio_trigger_list */
141 list_for_each_entry_safe(trig,
143 &iio_gpio_trigger_list,
145 trig_info = trig->private_data;
146 free_irq(gpio_to_irq(trig_info->gpio), trig);
147 gpio_free(trig_info->gpio);
150 iio_trigger_unregister(trig);
157 static int iio_gpio_trigger_remove(struct platform_device *dev)
159 struct iio_trigger *trig, *trig2;
160 struct iio_gpio_trigger_info *trig_info;
162 mutex_lock(&iio_gpio_trigger_list_lock);
163 list_for_each_entry_safe(trig,
165 &iio_gpio_trigger_list,
167 trig_info = trig->private_data;
168 iio_trigger_unregister(trig);
169 free_irq(gpio_to_irq(trig_info->gpio), trig);
170 gpio_free(trig_info->gpio);
173 iio_put_trigger(trig);
175 mutex_unlock(&iio_gpio_trigger_list_lock);
180 static struct platform_driver iio_gpio_trigger_driver = {
181 .probe = iio_gpio_trigger_probe,
182 .remove = iio_gpio_trigger_remove,
184 .name = "iio_gpio_trigger",
185 .owner = THIS_MODULE,
189 static int __init iio_gpio_trig_init(void)
191 return platform_driver_register(&iio_gpio_trigger_driver);
193 module_init(iio_gpio_trig_init);
195 static void __exit iio_gpio_trig_exit(void)
197 platform_driver_unregister(&iio_gpio_trigger_driver);
199 module_exit(iio_gpio_trig_exit);
201 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
202 MODULE_DESCRIPTION("Example gpio trigger for the iio subsystem");
203 MODULE_LICENSE("GPL v2");