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>
26 #include "../trigger.h"
28 LIST_HEAD(iio_gpio_trigger_list);
29 DEFINE_MUTEX(iio_gpio_trigger_list_lock);
31 struct iio_gpio_trigger_info {
36 * Need to reference count these triggers and only enable gpio interrupts
40 /* So what functionality do we want in here?... */
41 /* set high / low as interrupt type? */
43 static irqreturn_t iio_gpio_trigger_poll(int irq, void *private)
45 iio_trigger_poll(private);
49 DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
51 static struct attribute *iio_gpio_trigger_attrs[] = {
56 static const struct attribute_group iio_gpio_trigger_attr_group = {
57 .attrs = iio_gpio_trigger_attrs,
60 static int iio_gpio_trigger_probe(struct platform_device *dev)
62 int *pdata = dev->dev.platform_data;
63 struct iio_gpio_trigger_info *trig_info;
64 struct iio_trigger *trig, *trig2;
67 printk(KERN_ERR "No IIO gpio trigger platform data found\n");
71 if (!gpio_is_valid(pdata[i]))
73 trig = iio_allocate_trigger();
76 goto error_free_completed_registrations;
79 trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
82 goto error_put_trigger;
84 trig->control_attrs = &iio_gpio_trigger_attr_group;
85 trig->private_data = trig_info;
86 trig_info->gpio = pdata[i];
87 trig->owner = THIS_MODULE;
88 trig->name = kmalloc(IIO_TRIGGER_NAME_LENGTH, GFP_KERNEL);
91 goto error_free_trig_info;
93 snprintf((char *)trig->name,
94 IIO_TRIGGER_NAME_LENGTH,
97 ret = gpio_request(trig_info->gpio, trig->name);
101 ret = gpio_direction_input(trig_info->gpio);
103 goto error_release_gpio;
105 irq = gpio_to_irq(trig_info->gpio);
108 goto error_release_gpio;
111 ret = request_irq(irq, iio_gpio_trigger_poll,
116 goto error_release_gpio;
118 ret = iio_trigger_register(trig);
120 goto error_release_irq;
122 list_add_tail(&trig->alloc_list, &iio_gpio_trigger_list);
127 /* First clean up the partly allocated trigger */
131 gpio_free(trig_info->gpio);
134 error_free_trig_info:
137 iio_put_trigger(trig);
138 error_free_completed_registrations:
139 /* The rest should have been added to the iio_gpio_trigger_list */
140 list_for_each_entry_safe(trig,
142 &iio_gpio_trigger_list,
144 trig_info = trig->private_data;
145 free_irq(gpio_to_irq(trig_info->gpio), trig);
146 gpio_free(trig_info->gpio);
149 iio_trigger_unregister(trig);
156 static int iio_gpio_trigger_remove(struct platform_device *dev)
158 struct iio_trigger *trig, *trig2;
159 struct iio_gpio_trigger_info *trig_info;
161 mutex_lock(&iio_gpio_trigger_list_lock);
162 list_for_each_entry_safe(trig,
164 &iio_gpio_trigger_list,
166 trig_info = trig->private_data;
167 iio_trigger_unregister(trig);
168 free_irq(gpio_to_irq(trig_info->gpio), trig);
169 gpio_free(trig_info->gpio);
172 iio_put_trigger(trig);
174 mutex_unlock(&iio_gpio_trigger_list_lock);
179 static struct platform_driver iio_gpio_trigger_driver = {
180 .probe = iio_gpio_trigger_probe,
181 .remove = iio_gpio_trigger_remove,
183 .name = "iio_gpio_trigger",
184 .owner = THIS_MODULE,
188 static int __init iio_gpio_trig_init(void)
190 return platform_driver_register(&iio_gpio_trigger_driver);
192 module_init(iio_gpio_trig_init);
194 static void __exit iio_gpio_trig_exit(void)
196 platform_driver_unregister(&iio_gpio_trigger_driver);
198 module_exit(iio_gpio_trig_exit);
200 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
201 MODULE_DESCRIPTION("Example gpio trigger for the iio subsystem");
202 MODULE_LICENSE("GPL v2");