diff options
Diffstat (limited to 'drivers/input/serio/parkbd.c')
| -rw-r--r-- | drivers/input/serio/parkbd.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/drivers/input/serio/parkbd.c b/drivers/input/serio/parkbd.c new file mode 100644 index 0000000000..0d54895428 --- /dev/null +++ b/drivers/input/serio/parkbd.c @@ -0,0 +1,223 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Parallel port to Keyboard port adapter driver for Linux + * + * Copyright (c) 1999-2004 Vojtech Pavlik + */ + + +/* + * 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(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; +} + +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; + strscpy(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 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; +} + +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; +} + +static struct parport_driver parkbd_parport_driver = { + .name = "parkbd", + .match_port = parkbd_attach, + .detach = parkbd_detach, + .devmodel = true, +}; +module_parport_driver(parkbd_parport_driver); |