# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1457153703 0
# Node ID a7543d592206226a1bf97a2b9ecee05c81f3bddb
# Parent  acfcd119e53248bb582a9a2862f652b502534be2
- interrupt debouncing (crude)
- blinking another led when pressing the button
- using broadcom custom pullup/down function

diff -r acfcd119e532 -r a7543d592206 gpio.c
--- a/gpio.c	Sat Mar 05 04:25:33 2016 +0000
+++ b/gpio.c	Sat Mar 05 04:55:03 2016 +0000
@@ -5,8 +5,11 @@
 #include <linux/interrupt.h>
 #include <asm/uaccess.h>
 #include <linux/gpio.h>
+#include <linux/jiffies.h>
+#include <linux/platform_data/bcm2708.h>
 
 #define TEST_OUTPUT_PIN	4
+#define TEST_OUTPUT_GREEN	17
 #define TEST_INPUT_PIN	22
 
 static int dev_init(void);
@@ -43,12 +46,14 @@
 	printk("gpio module registered (device: %d)\n", major);
 
 	gpio_direction_output(TEST_OUTPUT_PIN, 0);
-	gpio_direction_input(TEST_INPUT_PIN);
+	gpio_direction_output(TEST_OUTPUT_GREEN, 0);
 
 	if(gpio_request(TEST_INPUT_PIN, "test_input") != 0) {
 		printk("gpio: failed to get input gpio pin\n");
 		return -1;
 	}
+	gpio_direction_input(TEST_INPUT_PIN);
+	bcm2708_gpio_setpull(gpio_to_chip(TEST_INPUT_PIN), TEST_INPUT_PIN, BCM2708_PULL_DOWN);
 	if((intr_num = gpio_to_irq(TEST_INPUT_PIN)) < 0) {
 		printk("gpio: failed to get interrupt line for gpio pin\n");
 		return -1;
@@ -65,12 +70,17 @@
 static void dev_exit(void)
 {
 	printk("gpio exit\n");
+
 	unregister_chrdev(major, "gpio");
 
 	if(intr_num != -1) {
 		free_irq(intr_num, "gpio");
 	}
 	gpio_free(TEST_INPUT_PIN);
+
+	gpio_direction_input(TEST_OUTPUT_PIN);
+	gpio_direction_input(TEST_OUTPUT_GREEN);
+	bcm2708_gpio_setpull(gpio_to_chip(TEST_INPUT_PIN), TEST_INPUT_PIN, BCM2708_PULL_OFF);
 }
 
 static int dev_open(struct inode *inode, struct file *file)
@@ -89,8 +99,6 @@
 {
 	unsigned char val;
 
-	printk("dev_write(%d) called\n", sz);
-
 	if(sz < 1) {
 		return 0;
 	}
@@ -104,6 +112,15 @@
 
 static irqreturn_t intr_handler(int inum, void *devid, struct pt_regs *regs)
 {
+	static unsigned long ignore_until;
+	unsigned long now = jiffies;
+
+	if(time_before(now, ignore_until)) {
+		return IRQ_HANDLED;
+	}
+	ignore_until = now + 128 * HZ / 1000;
+
 	printk("presses: %d\n", num_presses++);
+	gpio_set_value(TEST_OUTPUT_GREEN, num_presses & 1);
 	return IRQ_HANDLED;
 }