restore old state when unloading module

[ms2-fixes] / debounce.c

diff --git a/debounce.c b/debounce.c
index 9ae93f2283ed75259d37275d3013395d02947426..4006cd2a4c81310e4aa1efa0f3adcd8b4642fc78 100644 (file)
--- a/debounce.c
+++ b/debounce.c
@@ -5,10 +5,13 @@
 
 #define PREFIX "debounce: "
 
-static int delay = 10;
+static int debounce_delay = 10;
 
-module_param(delay, int, S_IRUSR | S_IRGRP | S_IROTH);
-MODULE_PARM_DESC(delay, "debouncing delay (ms), default: 10");
+static int old_delay = 0;
+static struct gpio_event_matrix_info *gpio_evmi = NULL;
+
+module_param(debounce_delay, int, S_IRUSR | S_IRGRP | S_IROTH);
+MODULE_PARM_DESC(debounce_delay, "debouncing delay (ms), default: 10");
 
 static int find_ms2_dev(struct device *dev, void *data)
 {
@@ -24,7 +27,6 @@ static int __init debounce_init(void)
        struct device *event_dev = NULL;
        struct gpio_event_platform_data *gpio_epd;
        struct gpio_event_info *gpio_ei;
-       struct gpio_event_matrix_info *gpio_evmi;
 
        printk(KERN_INFO PREFIX "Searching for " GPIO_EVENT_DEV_NAME "...\n");
 
@@ -53,9 +55,11 @@ static int __init debounce_init(void)
                printk(KERN_INFO PREFIX "flags: 0x%x\n", gpio_evmi->flags);
        }
 
-       if (gpio_evmi->debounce_delay.tv.nsec != delay * NSEC_PER_MSEC) {
+       old_delay = gpio_evmi->debounce_delay.tv.nsec;
+
+       if (gpio_evmi->debounce_delay.tv.nsec != debounce_delay * NSEC_PER_MSEC) {
                printk(KERN_INFO PREFIX "Changing debounce_delay\n");
-               gpio_evmi->debounce_delay.tv.nsec = delay * NSEC_PER_MSEC;
+               gpio_evmi->debounce_delay.tv.nsec = debounce_delay * NSEC_PER_MSEC;
                printk(KERN_INFO PREFIX "debounce_delay: %u\n", gpio_evmi->debounce_delay.tv.nsec);
        }
 
@@ -64,6 +68,13 @@ static int __init debounce_init(void)
 
 static void __exit debounce_exit(void)
 {
+       if (gpio_evmi) {
+               if (gpio_evmi->debounce_delay.tv.nsec != old_delay) {
+                       printk(KERN_INFO PREFIX "Restoring debounce_delay\n");
+                       gpio_evmi->debounce_delay.tv.nsec = old_delay;
+                       printk(KERN_INFO PREFIX "debounce_delay: %u\n", gpio_evmi->debounce_delay.tv.nsec);
+               }
+       }
 }
 
 module_init(debounce_init);