cregit-Linux how code gets into the kernel

Release 4.11 drivers/input/serio/parkbd.c

/*
 *  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; }

Contributors

PersonTokensPropCommitsCommitProp
Vojtech Pavlik22100.00%1100.00%
Total22100.00%1100.00%


static void parkbd_writelines(int data) { parport_write_control(parkbd_dev->port, (~data & 3) | 0x10); }

Contributors

PersonTokensPropCommitsCommitProp
Vojtech Pavlik25100.00%1100.00%
Total25100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Vojtech Pavlik96100.00%1100.00%
Total96100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Vojtech Pavlik177100.00%2100.00%
Total177100.00%2100.00%


static int parkbd_getport(struct parport *pp) { struct pardev_cb parkbd_parport_cb; memset(&parkbd_parport_cb, 0, sizeof(parkbd_parport_cb)); parkbd_parport_cb.irq_func = parkbd_interrupt; parkbd_parport_cb.flags = PARPORT_FLAG_EXCL; parkbd_dev = parport_register_dev_model(pp, "parkbd", &parkbd_parport_cb, 0); if (!parkbd_dev) return -ENODEV; if (parport_claim(parkbd_dev)) { parport_unregister_device(parkbd_dev); return -EBUSY; } parkbd_start = jiffies; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Vojtech Pavlik5562.50%125.00%
Sudip Mukherjee3135.23%250.00%
Al Viro22.27%125.00%
Total88100.00%4100.00%


static struct serio *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; }

Contributors

PersonTokensPropCommitsCommitProp
Dmitry Torokhov6674.16%250.00%
Vojtech Pavlik2224.72%125.00%
Eric Sesterhenn / Snakebyte11.12%125.00%
Total89100.00%4100.00%


static void parkbd_attach(struct parport *pp) { if (pp->number != parkbd_pp_no) { pr_debug("Not using parport%d.\n", pp->number); return; } if (parkbd_getport(pp)) return; parkbd_port = parkbd_allocate_serio(); if (!parkbd_port) { parport_release(parkbd_dev); parport_unregister_device(parkbd_dev); return; } 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; }

Contributors

PersonTokensPropCommitsCommitProp
Sudip Mukherjee3740.66%240.00%
Dmitry Torokhov2931.87%120.00%
Vojtech Pavlik2426.37%120.00%
Adrian Bunk11.10%120.00%
Total91100.00%5100.00%


static void parkbd_detach(struct parport *port) { if (!parkbd_port || port->number != parkbd_pp_no) return; parport_release(parkbd_dev); serio_unregister_port(parkbd_port); parport_unregister_device(parkbd_dev); parkbd_port = NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Sudip Mukherjee2252.38%133.33%
Vojtech Pavlik1945.24%133.33%
Adrian Bunk12.38%133.33%
Total42100.00%3100.00%

static struct parport_driver parkbd_parport_driver = { .name = "parkbd", .match_port = parkbd_attach, .detach = parkbd_detach, .devmodel = true, };
static int __init parkbd_init(void) { return parport_register_driver(&parkbd_parport_driver); }

Contributors

PersonTokensPropCommitsCommitProp
Sudip Mukherjee16100.00%1100.00%
Total16100.00%1100.00%


static void __exit parkbd_exit(void) { parport_unregister_driver(&parkbd_parport_driver); }

Contributors

PersonTokensPropCommitsCommitProp
Sudip Mukherjee1493.33%150.00%
Vojtech Pavlik16.67%150.00%
Total15100.00%2100.00%

module_init(parkbd_init); module_exit(parkbd_exit);

Overall Contributors

PersonTokensPropCommitsCommitProp
Vojtech Pavlik52864.16%426.67%
Sudip Mukherjee14717.86%320.00%
Dmitry Torokhov13816.77%320.00%
Tejun Heo30.36%16.67%
Adrian Bunk20.24%16.67%
Andrew Morton20.24%16.67%
Al Viro20.24%16.67%
Eric Sesterhenn / Snakebyte10.12%16.67%
Total823100.00%15100.00%
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