/* * Parallel port to Keyboard port adapter driver for Linux * * Copyright (c) 1999-2004 Vojtech Pavlik */ /* * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published by * the Free Software Foundation. */ /* * To connect an AT or XT keyboard to the parallel port, a fairly simple adapter * can be made: * * Parallel port Keyboard port * * +5V --------------------- +5V (4) * * ______ * +5V -------|______|--. * | * ACK (10) ------------| * |--- KBD CLOCK (5) * STROBE (1) ---|<|----' * * ______ * +5V -------|______|--. * | * BUSY (11) -----------| * |--- KBD DATA (1) * AUTOFD (14) --|<|----' * * GND (18-25) ------------- GND (3) * * The diodes can be fairly any type, and the resistors should be somewhere * around 5 kOhm, but the adapter will likely work without the resistors, * too. * * The +5V source can be taken either from USB, from mouse or keyboard ports, * or from a joystick port. Unfortunately, the parallel port of a PC doesn't * have a +5V pin, and feeding the keyboard from signal pins is out of question * with 300 mA power reqirement of a typical AT keyboard. */ #include <linux/module.h> #include <linux/parport.h> #include <linux/init.h> #include <linux/serio.h> MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); MODULE_DESCRIPTION("Parallel port to Keyboard port adapter driver"); MODULE_LICENSE("GPL"); static unsigned int parkbd_pp_no; module_param_named(port, parkbd_pp_no, int, 0); MODULE_PARM_DESC(port, "Parallel port the adapter is connected to (default is 0)"); static unsigned int parkbd_mode = SERIO_8042; module_param_named(mode, parkbd_mode, uint, 0); MODULE_PARM_DESC(mode, "Mode of operation: XT = 0/AT = 1 (default)"); #define PARKBD_CLOCK 0x01 /* Strobe & Ack */ #define PARKBD_DATA 0x02 /* AutoFd & Busy */ static int parkbd_buffer; static int parkbd_counter; static unsigned long parkbd_last; static int parkbd_writing; static unsigned long parkbd_start; static struct pardevice *parkbd_dev; static struct serio *parkbd_port; static int parkbd_readlines(void) { return (parport_read_status(parkbd_dev->port) >> 6) ^ 2; } static void parkbd_writelines(int data) { parport_write_control(parkbd_dev->port, (~data & 3) | 0x10); } static int parkbd_write(struct serio *port, unsigned char c) { unsigned char p; if (!parkbd_mode) return -1; p = c ^ (c >> 4); p = p ^ (p >> 2); p = p ^ (p >> 1); parkbd_counter = 0; parkbd_writing = 1; parkbd_buffer = c | (((int) (~p & 1)) << 8) | 0x600; parkbd_writelines(2); return 0; } static void parkbd_interrupt(int irq, void *dev_id, struct pt_regs *regs) { if (parkbd_writing) { if (parkbd_counter && ((parkbd_counter == 11) || time_after(jiffies, parkbd_last + HZ/100))) { parkbd_counter = 0; parkbd_buffer = 0; parkbd_writing = 0; parkbd_writelines(3); return; } parkbd_writelines(((parkbd_buffer >> parkbd_counter++) & 1) | 2); if (parkbd_counter == 11) { parkbd_counter = 0; parkbd_buffer = 0; parkbd_writing = 0; parkbd_writelines(3); } } else { if ((parkbd_counter == parkbd_mode + 10) || time_after(jiffies, parkbd_last + HZ/100)) { parkbd_counter = 0; parkbd_buffer = 0; } parkbd_buffer |= (parkbd_readlines() >> 1) << parkbd_counter++; if (parkbd_counter == parkbd_mode + 10) serio_interrupt(parkbd_port, (parkbd_buffer >> (2 - parkbd_mode)) & 0xff, 0, regs); } parkbd_last = jiffies; } static int parkbd_getport(void) { struct parport *pp; pp = parport_find_number(parkbd_pp_no); if (pp == NULL) { printk(KERN_ERR "parkbd: no such parport\n"); return -ENODEV; } parkbd_dev = parport_register_device(pp, "parkbd", NULL, NULL, parkbd_interrupt, PARPORT_DEV_EXCL, NULL); parport_put_port(pp); if (!parkbd_dev) return -ENODEV; if (parport_claim(parkbd_dev)) { parport_unregister_device(parkbd_dev); return -EBUSY; } parkbd_start = jiffies; return 0; } static struct serio * __init parkbd_allocate_serio(void) { struct serio *serio; serio = kzalloc(sizeof(struct serio), GFP_KERNEL); if (serio) { serio->id.type = parkbd_mode; serio->write = parkbd_write, strlcpy(serio->name, "PARKBD AT/XT keyboard adapter", sizeof(serio->name)); snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", parkbd_dev->port->name); } return serio; } static int __init parkbd_init(void) { int err; err = parkbd_getport(); if (err) return err; parkbd_port = parkbd_allocate_serio(); if (!parkbd_port) { parport_release(parkbd_dev); return -ENOMEM; } parkbd_writelines(3); serio_register_port(parkbd_port); printk(KERN_INFO "serio: PARKBD %s adapter on %s\n", parkbd_mode ? "AT" : "XT", parkbd_dev->port->name); return 0; } static void __exit parkbd_exit(void) { parport_release(parkbd_dev); serio_unregister_port(parkbd_port); parport_unregister_device(parkbd_dev); } module_init(parkbd_init); module_exit(parkbd_exit);