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 = 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>");