Registering port
/* Registering port */ port = check_region(0x378, 1); //0x378 是 Parallel port 的位置 if (port) { printk("parlelport: cannot reserve 0x378\n"); result = port; goto fail; } request_region(0x378, 1, "parlelport");
那 COM ports 在 PC-compatible are typically 定義是:
COM1: I/O port 0x3F8, IRQ 4
COM2: I/O port 0x2F8, IRQ 3
COM3: I/O port 0x3E8, IRQ 4
COM4: I/O port 0x2E8, IRQ 3