adc.rar_2410 adc

#include <linux/config.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/miscdevice.h> #include <linux/sched.h> #include <linux/delay.h> #include <linux/poll.h> #include <linux/spinlock.h> #include <linux/irq.h> #include <linux/delay.h> #include <asm/hardware.h> #define DEVICE_NAME "adc" #define ADC_MAJOR 239 #define LOOP 100000 static int ready = 0; //static int adc_value = 0; //static DECLARE_WAIT_QUEUE_HEAD(buttons_wait); static int adc_read(struct file * file, char * buffer, size_t count, loff_t *ppos) { int adcdata; int i; int preScaler; static int prevCh=-1; int ch=0; preScaler=0xFF; ADCCON=(1<<14)|(preScaler<<6)|(ch<<3); if(prevCh!=ch) { ADCCON=(1<<14)|(preScaler<<6)|(ch<<3); for(i=0;i<LOOP;i++); prevCh=ch; } ADCCON|=0x1; while(ADCCON&0x1); while(!(ADCCON&0x8000)); adcdata=(int)ADCDAT0&0x3ff; copy_to_user(buffer, (char *)&adcdata, sizeof(adcdata)); return sizeof adcdata; } static int adc_open(struct inode *inode, struct file *filp) { MOD_INC_USE_COUNT; printk( "adc opened\n"); return 0; } static int adc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { switch(cmd) { default: return -EINVAL; } } static int adc_release(struct inode *inode, struct file *filp) { MOD_DEC_USE_COUNT; printk( "adc closed\n"); return 0; } static struct file_operations adc_fops = { owner: THIS_MODULE, open: adc_open, ioctl: adc_ioctl, //poll: matrix4_buttons_select, read: adc_read, release: adc_release, }; static devfs_handle_t devfs_handle; static int __init adc_init(void) { int ret; ready = 0; ret = register_chrdev(ADC_MAJOR, DEVICE_NAME, &adc_fops); if (ret < 0) { printk(DEVICE_NAME " can't register major number\n"); return ret; } devfs_handle = devfs_register(NULL, DEVICE_NAME, DEVFS_FL_DEFAULT, ADC_MAJOR, 0, S_IFCHR | S_IRUSR | S_IWUSR, &adc_fops, NULL);//向VFS注册统一的设备操作函数 ///dev处的设备入口在设备初始化时建立,设备移除时删除. //设备驱动和用户空间程序都可以改变所有性和许可权. //不必分配主设备号,不必处理次设备号. return 0; } static void __exit adc_exit(void) { devfs_unregister(devfs_handle); unregister_chrdev(ADC_MAJOR, DEVICE_NAME); } module_init(adc_init); module_exit(adc_exit); MODULE_LICENSE("GPL");