/*
* 读取设备寄存器val的值，保存在page缓冲区中
*/
static ssize_t hello_proc_read(char* page, char** start, off_t off, int count, int* eof, void* data){
if(off > 0){
*eof = 1;
return 0;
}
return __hello_get_val(hello_dev, page);
}
/*读取设备属性val*/
static ssize_t hello_val_show(struct device* dev, struct device_attribute* attr, char* buf) {
struct hello_android_dev* hdev = (struct hello_android_dev*)dev_get_drvdata(dev);
return __hello_get_val(hdev, buf);
}