/*
* Parallel port to Walkera WK-0701 TX joystick
*
* Copyright (c) 2008 Peter Popovec
*
* More about driver: <file:Documentation/input/walkera0701.txt>
*/
/*
* 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.
*/
/* #define WK0701_DEBUG */
#define RESERVE 20000
#define SYNC_PULSE 1306000
#define BIN0_PULSE 288000
#define BIN1_PULSE 438000
#define ANALOG_MIN_PULSE 318000
#define ANALOG_MAX_PULSE 878000
#define ANALOG_DELTA 80000
#define BIN_SAMPLE ((BIN0_PULSE + BIN1_PULSE) / 2)
#define NO_SYNC 25
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/parport.h>
#include <linux/input.h>
#include <linux/hrtimer.h>
MODULE_AUTHOR("Peter Popovec <popovec@fei.tuke.sk>");
MODULE_DESCRIPTION("Walkera WK-0701 TX as joystick");
MODULE_LICENSE("GPL");
static unsigned int walkera0701_pp_no;
module_param_named(port, walkera0701_pp_no, int, 0);
MODULE_PARM_DESC(port,
"Parallel port adapter for Walkera WK-0701 TX (default is 0)");
/*
* For now, only one device is supported, if somebody need more devices, code
* can be expanded, one struct walkera_dev per device must be allocated and
* set up by walkera0701_connect (release of device by walkera0701_disconnect)
*/
struct walkera_dev {
unsigned char buf[25];
u64 irq_time, irq_lasttime;
int counter;
int ack;
struct input_dev *input_dev;
struct hrtimer timer;
struct parport *parport;
struct pardevice *pardevice;
};
static struct walkera_dev w_dev;
static inline void walkera0701_parse_frame(struct walkera_dev *w)
{
int i;
int val1, val2, val3, val4, val5, val6, val7, val8;
int crc1, crc2;
for (crc1 = crc2 = i = 0; i < 10; i++) {
crc1 += w->buf[i] & 7;
crc2 += (w->buf[i] & 8) >> 3;
}
if ((w->buf[10] & 7) != (crc1 & 7))
return;
if (((w->buf[10] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
return;
for (crc1 = crc2 = 0, i = 11; i < 23; i++) {
crc1 += w->buf[i] & 7;
crc2 += (w->buf[i] & 8) >> 3;
}
if ((w->buf[23] & 7) != (crc1 & 7))
return;
if (((w->buf[23] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
return;
val1 = ((w->buf[0] & 7) * 256 + w->buf[1] * 16 + w->buf[2]) >> 2;
val1 *= ((w->buf[0] >> 2) & 2) - 1; /* sign */
val2 = (w->buf[2] & 1) << 8 | (w->buf[3] << 4) | w->buf[4];
val2 *= (w->buf[2] & 2) - 1; /* sign */
val3 = ((w->buf[5] & 7) * 256 + w->buf[6] * 16 + w->buf[7]) >> 2;
val3 *= ((w->buf[5] >> 2) & 2) - 1; /* sign */
val4 = (w->buf[7] & 1) << 8 | (w->buf[8] << 4) | w->buf[9];
val4 *= (w->buf[7] & 2) - 1; /* sign */
val5 = ((w->buf[11] & 7) * 256 + w->buf[12] * 16 + w->buf[13]) >> 2;
val5 *= ((w->buf[11] >> 2) & 2) - 1; /* sign */
val6 = (w->buf[13] & 1) << 8 | (w->buf[14] << 4) | w->buf[15];
val6 *= (w->buf[13] & 2) - 1; /* sign */
val7 = ((w->buf[16] & 7) * 256 + w->buf[17] * 16 + w->buf[18]) >> 2;
val7 *= ((w->buf[16] >> 2) & 2) - 1; /*sign */
val8 = (w->buf[18] & 1) << 8 | (w->buf[19] << 4) | w->buf[20];
val8 *= (w->buf[18] & 2) - 1; /*sign */
#ifdef WK0701_DEBUG
{
int magic, magic_bit;
magic = (w->buf[21] << 4) | w->buf[22];
magic_bit = (w->buf[24] & 8) >> 3;
printk(KERN_DEBUG
"walkera0701: %4d %4d %4d %4d %4d %4d %4d %4d (magic %2x %d)\n",
val1, val2, val3, val4, val5, val6, val7, val8, magic,
magic_bit);
}
#endif
input_report_abs(w->input_dev, ABS_X, val2);
input_report_abs(w->input_dev, ABS_Y, val1);
input_report_abs(w->input_dev, ABS_Z, val6);
input_report_abs(w->input_dev, ABS_THROTTLE, val3);
input_report_abs(w->input_dev, ABS_RUDDER, val4);
input_report_abs(w->input_dev, ABS_MISC, val7);
input_report_key(w->input_dev, BTN_GEAR_DOWN, val5 > 0);
}
static inline int read_ack(struct pardevice *p)
{
return parport_read_status(p->port) & 0x40;
}
/* falling edge, prepare to BIN value calculation */
static void walkera0701_irq_handler(void *handler_data)
{
u64 pulse_time;
struct walkera_dev *w = handler_data;
w->irq_time = ktime_to_ns(ktime_get());
pulse_time = w->irq_time - w->irq_lasttime;
w->irq_lasttime = w->irq_time;
/* cancel timer, if in handler or active do resync */
if (unlikely(0 != hrtimer_try_to_cancel(&w->timer))) {
w->counter = NO_SYNC;
return;
}
if (w->counter < NO_SYNC) {
if (w->ack) {
pulse_time -= BIN1_PULSE;
w->buf[w->counter] = 8;
} else {
pulse_time -= BIN0_PULSE;
w->buf[w->counter] = 0;
}
if (w->counter == 24) { /* full frame */
walkera0701_parse_frame(w);
w->counter = NO_SYNC;
if (abs(pulse_time - SYNC_PULSE) < RESERVE) /* new frame sync */
w->counter = 0;
} else {
if ((pulse_time > (ANALOG_MIN_PULSE - RESERVE)
&& (pulse_time < (ANALOG_MAX_PULSE + RESERVE)))) {
pulse_time -= (ANALOG_MIN_PULSE - RESERVE);
pulse_time = (u32) pulse_time / ANALOG_DELTA; /* overtiping is safe, pulsetime < s32.. */
w->buf[w->counter++] |= (pulse_time & 7);
} else
w->counter = NO_SYNC;
}
} else if (abs(pulse_time - SYNC_PULSE - BIN0_PULSE) <
RESERVE + BIN1_PULSE - BIN0_PULSE) /* frame sync .. */
w->counter = 0;
hrtimer_start(&w->timer, ktime_set(0, BIN_SAMPLE), HRTIMER_MODE_REL);
}
static enum hrtimer_restart timer_handler(struct hrtimer
*handle)
{
struct walkera_dev *w;
w = container_of(handle, struct walkera_dev, timer);
w->ack = read_ack(w->pardevice);
return HRTIMER_NORESTART;
}
static int walkera0701_open(struct input_dev *dev)
{
struct walkera_dev *w = input_get_drvdata(dev);
parport_enable_irq(w->parport);
return 0;
}
static void walkera0701_close(struct input_dev *dev)
{
struct walkera_dev *w = input_get_drvdata(dev);
parport_disable_irq(w->parport);
}
static int walkera0701_connect(struct walkera_dev *w, int parport)
{
int err = -ENODEV;
w->parport = parport_find_number(parport);
if (w->parport == NULL)
return -ENODEV;
if (w->parport->irq == -1) {
printk(KERN_ERR "walkera0701: parport without interrupt\n");
goto init_err;
}
err = -EBUSY;
w->pardevice = parport_register_device(w->parport, "walkera0701",
NULL, NULL, walkera0701_irq_handler,
PARPORT_DEV_EXCL, w);
if (!w->pardevice)
goto init_err;
if (parport_negotiate(w->pardevice->port, IEEE1284_MODE_COMPAT))
goto init_err1;
if (parport_claim(w->pardevice))
goto init_err1;
w->input_dev = input_allocate_device();
if (!w->input_dev)
goto init_err2;
input_set_drvdata(w->input_dev, w);
w->input_dev->name = "Walkera WK-0701 TX";
w->input_dev->phys = w->parport->name;
w->input_dev->id.bustype = BUS_PARPORT;
/* TODO what id vendor/product/version ? */
w->input_dev->id.vendor = 0x0001;
w->input_dev->id.product = 0x0001;
w->input_dev->id.version = 0x0100;
w->input_dev->open = walkera0701_open;
w->input_dev->close = walkera0701_close;
w->input_dev->evbit[0] = BIT(EV_ABS) | BIT_MASK(EV_KEY);
w->input_dev->keybit[BIT_WORD(BTN_GEAR_DOWN)] = BIT_MASK(BTN_GEAR_DOWN);
input_set_abs_params(w->input_dev, ABS_X, -512, 512, 0, 0);
input_set_abs_params(w->input_dev, ABS_Y, -512, 512, 0, 0);
input_set_abs_params(w->input_dev, ABS_Z, -512, 512, 0, 0);
input_set_abs_params(w->input_dev, ABS_THROTTLE, -512, 512, 0, 0);
input_set_abs_params(w->input_dev, ABS_RUDDER, -512, 512, 0, 0);
input_set_abs_params(w->input_dev, ABS_MISC, -512, 512, 0, 0);
err = input_register_device(w->input_dev);
if (err)
goto init_err3;
hrtimer_init(&w->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
w->timer.function = timer_handler;
return 0;
init_err3:
input_free_device(w->input_dev);
init_err2:
parport_release(w->pardevice);
init_err1:
parport_unregister_device(w->pardevice);
init_err:
parport_put_port(w->parport);
return err;
}
static void walkera0701_disconnect(struct walkera_dev *w)
{
hrtimer_cancel(&w->timer);
input_unregister_device(w->input_dev);
parport_release(w->pardevice);
parport_unregister_device(w->pardevice);
parport_put_port(w->parport);
}
static int __init walkera0701_init(void)
{
return walkera0701_connect(&w_dev, walkera0701_pp_no);
}
static void __exit walkera0701_exit(void)
{
walkera0701_disconnect(&w_dev);
}
module_init(walkera0701_init);
module_exit(walkera0701_exit);
