/drivers/staging/iio/trigger/iio-trig-gpio.c
C | 173 lines | 122 code | 26 blank | 25 comment | 11 complexity | 3319f2cd7dd50843a9b8a830c5f4dbf2 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
1/*
2 * Industrial I/O - gpio based trigger support
3 *
4 * Copyright (c) 2008 Jonathan Cameron
5 *
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.
9 *
10 * Currently this is more of a functioning proof of concept that a fully
11 * fledged trigger driver.
12 *
13 * TODO:
14 *
15 * Add board config elements to allow specification of startup settings.
16 */
17
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/platform_device.h>
21#include <linux/interrupt.h>
22#include <linux/gpio.h>
23#include <linux/slab.h>
24
25#include "../iio.h"
26#include "../trigger.h"
27
28static LIST_HEAD(iio_gpio_trigger_list);
29static DEFINE_MUTEX(iio_gpio_trigger_list_lock);
30
31struct iio_gpio_trigger_info {
32 struct mutex in_use;
33 unsigned int irq;
34};
35/*
36 * Need to reference count these triggers and only enable gpio interrupts
37 * as appropriate.
38 */
39
40/* So what functionality do we want in here?... */
41/* set high / low as interrupt type? */
42
43static irqreturn_t iio_gpio_trigger_poll(int irq, void *private)
44{
45 /* Timestamp not currently provided */
46 iio_trigger_poll(private, 0);
47 return IRQ_HANDLED;
48}
49
50static int iio_gpio_trigger_probe(struct platform_device *pdev)
51{
52 struct iio_gpio_trigger_info *trig_info;
53 struct iio_trigger *trig, *trig2;
54 unsigned long irqflags;
55 struct resource *irq_res;
56 int irq, ret = 0, irq_res_cnt = 0;
57
58 do {
59 irq_res = platform_get_resource(pdev,
60 IORESOURCE_IRQ, irq_res_cnt);
61
62 if (irq_res == NULL) {
63 if (irq_res_cnt == 0)
64 dev_err(&pdev->dev, "No GPIO IRQs specified");
65 break;
66 }
67 irqflags = (irq_res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
68
69 for (irq = irq_res->start; irq <= irq_res->end; irq++) {
70
71 trig = iio_allocate_trigger("irqtrig%d", irq);
72 if (!trig) {
73 ret = -ENOMEM;
74 goto error_free_completed_registrations;
75 }
76
77 trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
78 if (!trig_info) {
79 ret = -ENOMEM;
80 goto error_put_trigger;
81 }
82 trig->private_data = trig_info;
83 trig_info->irq = irq;
84 trig->owner = THIS_MODULE;
85 ret = request_irq(irq, iio_gpio_trigger_poll,
86 irqflags, trig->name, trig);
87 if (ret) {
88 dev_err(&pdev->dev,
89 "request IRQ-%d failed", irq);
90 goto error_free_trig_info;
91 }
92
93 ret = iio_trigger_register(trig);
94 if (ret)
95 goto error_release_irq;
96
97 list_add_tail(&trig->alloc_list,
98 &iio_gpio_trigger_list);
99 }
100
101 irq_res_cnt++;
102 } while (irq_res != NULL);
103
104
105 return 0;
106
107/* First clean up the partly allocated trigger */
108error_release_irq:
109 free_irq(irq, trig);
110error_free_trig_info:
111 kfree(trig_info);
112error_put_trigger:
113 iio_put_trigger(trig);
114error_free_completed_registrations:
115 /* The rest should have been added to the iio_gpio_trigger_list */
116 list_for_each_entry_safe(trig,
117 trig2,
118 &iio_gpio_trigger_list,
119 alloc_list) {
120 trig_info = trig->private_data;
121 free_irq(gpio_to_irq(trig_info->irq), trig);
122 kfree(trig_info);
123 iio_trigger_unregister(trig);
124 }
125
126 return ret;
127}
128
129static int iio_gpio_trigger_remove(struct platform_device *pdev)
130{
131 struct iio_trigger *trig, *trig2;
132 struct iio_gpio_trigger_info *trig_info;
133
134 mutex_lock(&iio_gpio_trigger_list_lock);
135 list_for_each_entry_safe(trig,
136 trig2,
137 &iio_gpio_trigger_list,
138 alloc_list) {
139 trig_info = trig->private_data;
140 iio_trigger_unregister(trig);
141 free_irq(trig_info->irq, trig);
142 kfree(trig_info);
143 iio_put_trigger(trig);
144 }
145 mutex_unlock(&iio_gpio_trigger_list_lock);
146
147 return 0;
148}
149
150static struct platform_driver iio_gpio_trigger_driver = {
151 .probe = iio_gpio_trigger_probe,
152 .remove = iio_gpio_trigger_remove,
153 .driver = {
154 .name = "iio_gpio_trigger",
155 .owner = THIS_MODULE,
156 },
157};
158
159static int __init iio_gpio_trig_init(void)
160{
161 return platform_driver_register(&iio_gpio_trigger_driver);
162}
163module_init(iio_gpio_trig_init);
164
165static void __exit iio_gpio_trig_exit(void)
166{
167 platform_driver_unregister(&iio_gpio_trigger_driver);
168}
169module_exit(iio_gpio_trig_exit);
170
171MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
172MODULE_DESCRIPTION("Example gpio trigger for the iio subsystem");
173MODULE_LICENSE("GPL v2");