git.zerfleddert.de Git - ms2-fixes/blob - 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 = 15;
   9
  10 static unsigned old_flags = 0;
  11 ktime_t old_debounce_delay;
  12 ktime_t old_settle_time;
  13 ktime_t old_poll_time;
  14 static struct gpio_event_matrix_info *gpio_evmi = NULL;
  15
  16 module_param(debounce_delay, int, S_IRUSR | S_IRGRP | S_IROTH);
  17 MODULE_PARM_DESC(debounce_delay, "debouncing delay (ms), default: 15");
  18
  19 static int find_ms2_dev(struct device *dev, void *data)
  20 {
  21         if (!strncmp((char*)data, dev_name(dev), strlen((char*)data))) {
  22                 printk(KERN_INFO PREFIX "Found it\n");
  23                 return 1;
  24         }
  25         return 0;
  26 }
  27
  28 static int __init debounce_init(void)
  29 {
  30         struct device *event_dev = NULL;
  31         struct gpio_event_platform_data *gpio_epd;
  32         struct gpio_event_info *gpio_ei;
  33
  34         printk(KERN_INFO PREFIX "Searching for " GPIO_EVENT_DEV_NAME "...\n");
  35
  36
  37         event_dev = device_find_child(&platform_bus, GPIO_EVENT_DEV_NAME, find_ms2_dev);
  38         if (event_dev == NULL)
  39                 return -ENODEV;
  40
  41         gpio_epd = (struct gpio_event_platform_data*)event_dev->platform_data;
  42         printk(KERN_INFO PREFIX "And there is a %s connected...\n", gpio_epd->name);
  43         if (strcmp(gpio_epd->name, "sholes-keypad"))
  44                 return -ENODEV;
  45
  46         gpio_ei = (struct gpio_event_info*)gpio_epd->info[0];
  47         gpio_evmi = container_of(gpio_ei, struct gpio_event_matrix_info, info);
  48
  49         printk(KERN_INFO PREFIX "settle_time: %u\n", gpio_evmi->settle_time.tv.nsec);
  50         printk(KERN_INFO PREFIX "poll_time: %u\n", gpio_evmi->poll_time.tv.nsec);
  51         printk(KERN_INFO PREFIX "debounce_delay: %u\n", gpio_evmi->debounce_delay.tv.nsec);
  52         printk(KERN_INFO PREFIX "flags: 0x%x\n", gpio_evmi->flags);
  53
  54         old_debounce_delay = gpio_evmi->debounce_delay;
  55         old_settle_time = gpio_evmi->settle_time;
  56         old_poll_time = gpio_evmi->poll_time;
  57         old_flags = gpio_evmi->flags;
  58
  59         if (gpio_evmi->debounce_delay.tv.nsec != debounce_delay * NSEC_PER_MSEC) {
  60                 printk(KERN_INFO PREFIX "Changing debounce_delay\n");
  61                 gpio_evmi->debounce_delay.tv.nsec = debounce_delay * NSEC_PER_MSEC;
  62                 printk(KERN_INFO PREFIX "debounce_delay: %u\n", gpio_evmi->debounce_delay.tv.nsec);
  63         }
  64
  65 #if 0
  66         gpio_evmi->flags &= ~GPIOKPF_REMOVE_SOME_PHANTOM_KEYS;
  67 #endif
  68
  69         if (gpio_evmi->debounce_delay.tv.nsec != 0) {
  70                 /* GPIOKPF_DEBOUNCE should already be set by GPIOKPF_REMOVE_PHANTOM_KEYS */
  71                 if (!(gpio_evmi->flags & GPIOKPF_DEBOUNCE)) {
  72                         printk(KERN_INFO PREFIX "Activating debounce\n");
  73                         gpio_evmi->flags |= GPIOKPF_DEBOUNCE;
  74                 }
  75         } else {
  76                 /* Deactivating GPIOKPF_DEBOUNCE */
  77                 printk(KERN_INFO PREFIX "Deactivating debounce\n");
  78                 gpio_evmi->flags &= ~GPIOKPF_DEBOUNCE;
  79         }
  80         printk(KERN_INFO PREFIX "flags: 0x%x\n", gpio_evmi->flags);
  81
  82         return 0;
  83 }
  84
  85 static void __exit debounce_exit(void)
  86 {
  87         if (gpio_evmi) {
  88                 if (gpio_evmi->debounce_delay.tv.nsec != old_debounce_delay.tv.nsec) {
  89                         printk(KERN_INFO PREFIX "Restoring debounce_delay\n");
  90                         gpio_evmi->debounce_delay = old_debounce_delay;
  91                         printk(KERN_INFO PREFIX "debounce_delay: %u\n", gpio_evmi->debounce_delay.tv.nsec);
  92                 }
  93                 if (gpio_evmi->flags != old_flags) {
  94                         printk(KERN_INFO PREFIX "Restoring flags\n");
  95                         gpio_evmi->flags = old_flags;
  96                         printk(KERN_INFO PREFIX "flags: 0x%x\n", gpio_evmi->flags);
  97                 }
  98                 gpio_evmi->settle_time = old_settle_time;
  99                 gpio_evmi->poll_time = old_poll_time;
 100         }
 101 }
 102
 103 module_init(debounce_init);
 104 module_exit(debounce_exit);
 105
 106 MODULE_LICENSE("GPL");
 107 MODULE_AUTHOR("Michael Gernoth <michael@gernoth.net>");