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buzzer_dev.c

+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+
+#include <asm/mach/map.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+
+#define BUZZER_MAJOR_NUMBER	502
+#define BUZZER_DEV_NAME 	"buzzer_ioctl"
+
+//GPIO18 
+#define GPIO_BASE_ADDR 0x3F200000
+#define GPFSEL1 0x04
+#define GPSET0 0x1C
+#define GPCLR0 0x28
+#define GPFSEL2 0x08
+#define GPLEV0 0x34
+
+
+#define IOCTL_MAGIC_NUMBER		'k'
+#define IOCTL_CMD_BUZZER_OFF			_IO(IOCTL_MAGIC_NUMBER, 0)
+#define IOCTL_CMD_BUZZER_ON				_IO(IOCTL_MAGIC_NUMBER, 1)
+#define IOCTL_CMD_BUTTON_CLICKED		_IO(IOCTL_MAGIC_NUMBER, 2)
+static void __iomem *gpio_base;
+volatile unsigned int *gpsel1;
+volatile unsigned int *gpset1;
+volatile unsigned int *gpclr1;
+volatile unsigned int *gpsel2;
+volatile unsigned int *gplev0;
+
+int buzzer_open(struct inode *inode, struct file *flip) {
+
+	printk(KERN_ALERT "buzzer driver open!!\n");
+
+	gpio_base = ioremap(GPIO_BASE_ADDR, 0x60);
+	gpsel1 = (volatile unsigned int *)(gpio_base + GPFSEL1);
+	gpset1 = (volatile unsigned int *)(gpio_base + GPSET0);
+	gpclr1 = (volatile unsigned int *)(gpio_base + GPCLR0);
+	gpsel2 = (volatile unsigned int *)(gpio_base + GPFSEL2);
+	gplev0 = (volatile unsigned int *)(gpio_base + GPLEV0);
+	//set direction out
+	*gpsel2 |= (1 << 3);
+	*gpsel1 |= (1 << 24);
+	*gpset1 |= (1 << 18);
+	*gpset1 |= (1 << 21);
+	return 0;
+}
+
+int buzzer_release(struct inode *inode, struct file *filp) {
+	printk(KERN_ALERT "buzzer driver closed!!\n");
+	iounmap((void *)gpio_base);
+	return 0;
+}
+
+long buzzer_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+
+	switch (cmd) {
+	case IOCTL_CMD_BUZZER_OFF:
+		printk(KERN_ALERT "buzzer off!!\n");
+		*gpset1 |= (1 << 18);
+		break;
+	case IOCTL_CMD_BUZZER_ON:
+		printk(KERN_ALERT "buzzer on!!\n");
+		*gpclr1 |= (1 << 18);
+		break;
+	case IOCTL_CMD_BUTTON_CLICKED:
+		printk(KERN_ALERT "button on!!\n");
+		
+		if((*gplev0 & (1<<20)) == (1<<20)){
+			return 0;
+		}else return 1;
+	}
+	return 0;
+}
+
+
+static struct file_operations buzzer_fops = {
+	.owner = THIS_MODULE,
+	.open = buzzer_open,
+	.release = buzzer_release,
+	.unlocked_ioctl = buzzer_ioctl
+};
+
+int __init buzzer_init(void) {
+	if (register_chrdev(BUZZER_MAJOR_NUMBER, BUZZER_DEV_NAME, &buzzer_fops) < 0)
+		printk(KERN_ALERT "buzzer driver initialization fail\n");
+	else
+		printk(KERN_ALERT "buzzer driver initailization success\n");
+
+	return 0;
+}
+
+void __exit buzzer_exit(void) {
+	unregister_chrdev(BUZZER_MAJOR_NUMBER, BUZZER_DEV_NAME);
+	printk(KERN_ALERT "buzzer driver exit done\n");
+}
+
+module_init(buzzer_init);
+module_exit(buzzer_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jaehoon");
+MODULE_DESCRIPTION("des");