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