--- /dev/null
+/*
+ * 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/slab.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(void *dev_id)
+{
+
+ 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);
+ }
+
+ 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);
Code Review / kvmfornfv.git / blobdiff