restore old state when unloading module
[ms2-fixes] / debounce.c
1 #include <linux/module.h>
2 #include <linux/device.h>
3 #include <linux/platform_device.h>
4 #include <linux/gpio_event.h>
5
6 #define PREFIX "debounce: "
7
8 static int debounce_delay = 10;
9
10 static int old_delay = 0;
11 static struct gpio_event_matrix_info *gpio_evmi = NULL;
12
13 module_param(debounce_delay, int, S_IRUSR | S_IRGRP | S_IROTH);
14 MODULE_PARM_DESC(debounce_delay, "debouncing delay (ms), default: 10");
15
16 static int find_ms2_dev(struct device *dev, void *data)
17 {
18 if (!strncmp((char*)data, dev_name(dev), strlen((char*)data))) {
19 printk(KERN_INFO PREFIX "Found it\n");
20 return 1;
21 }
22 return 0;
23 }
24
25 static int __init debounce_init(void)
26 {
27 struct device *event_dev = NULL;
28 struct gpio_event_platform_data *gpio_epd;
29 struct gpio_event_info *gpio_ei;
30
31 printk(KERN_INFO PREFIX "Searching for " GPIO_EVENT_DEV_NAME "...\n");
32
33
34 event_dev = device_find_child(&platform_bus, GPIO_EVENT_DEV_NAME, find_ms2_dev);
35 if (event_dev == NULL)
36 return -ENODEV;
37
38 gpio_epd = (struct gpio_event_platform_data*)event_dev->platform_data;
39 printk(KERN_INFO PREFIX "And there is a %s connected...\n", gpio_epd->name);
40 if (strcmp(gpio_epd->name, "sholes-keypad"))
41 return -ENODEV;
42
43 gpio_ei = (struct gpio_event_info*)gpio_epd->info[0];
44 gpio_evmi = container_of(gpio_ei, struct gpio_event_matrix_info, info);
45
46 printk(KERN_INFO PREFIX "settle_time: %u\n", gpio_evmi->settle_time.tv.nsec);
47 printk(KERN_INFO PREFIX "poll_time: %u\n", gpio_evmi->poll_time.tv.nsec);
48 printk(KERN_INFO PREFIX "debounce_delay: %u\n", gpio_evmi->debounce_delay.tv.nsec);
49 printk(KERN_INFO PREFIX "flags: 0x%x\n", gpio_evmi->flags);
50
51 /* GPIOKPF_DEBOUNCE should already be set by GPIOKPF_REMOVE_PHANTOM_KEYS */
52 if (!(gpio_evmi->flags & GPIOKPF_DEBOUNCE)) {
53 printk(KERN_INFO PREFIX "Activating debounce\n");
54 gpio_evmi->flags |= GPIOKPF_DEBOUNCE;
55 printk(KERN_INFO PREFIX "flags: 0x%x\n", gpio_evmi->flags);
56 }
57
58 old_delay = gpio_evmi->debounce_delay.tv.nsec;
59
60 if (gpio_evmi->debounce_delay.tv.nsec != debounce_delay * NSEC_PER_MSEC) {
61 printk(KERN_INFO PREFIX "Changing debounce_delay\n");
62 gpio_evmi->debounce_delay.tv.nsec = debounce_delay * NSEC_PER_MSEC;
63 printk(KERN_INFO PREFIX "debounce_delay: %u\n", gpio_evmi->debounce_delay.tv.nsec);
64 }
65
66 return 0;
67 }
68
69 static void __exit debounce_exit(void)
70 {
71 if (gpio_evmi) {
72 if (gpio_evmi->debounce_delay.tv.nsec != old_delay) {
73 printk(KERN_INFO PREFIX "Restoring debounce_delay\n");
74 gpio_evmi->debounce_delay.tv.nsec = old_delay;
75 printk(KERN_INFO PREFIX "debounce_delay: %u\n", gpio_evmi->debounce_delay.tv.nsec);
76 }
77 }
78 }
79
80 module_init(debounce_init);
81 module_exit(debounce_exit);
82
83 MODULE_LICENSE("GPL");
84 MODULE_AUTHOR("Michael Gernoth <michael@gernoth.net>");
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