/* * 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 pr_fmt(fmt) KBUILD_MODNAME ": " fmt #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 magic, magic_bit; 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 */ magic = (w->buf[21] << 4) | w->buf[22]; magic_bit = (w->buf[24] & 8) >> 3; pr_debug("%4d %4d %4d %4d %4d %4d %4d %4d (magic %2x %d)\n", val1, val2, val3, val4, val5, val6, val7, val8, magic, magic_bit); 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); if (parport_claim(w->pardevice)) return -EBUSY; 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); hrtimer_cancel(&w->timer); parport_release(w->pardevice); } static void walkera0701_attach(struct parport *pp) { struct pardev_cb walkera0701_parport_cb; struct walkera_dev *w = &w_dev; if (pp->number != walkera0701_pp_no) { pr_debug("Not using parport%d.\n", pp->number); return; } if (pp->irq == -1) { pr_err("parport %d does not have interrupt assigned\n", pp->number); return; } w->parport = pp; memset(&walkera0701_parport_cb, 0, sizeof(walkera0701_parport_cb)); walkera0701_parport_cb.flags = PARPORT_FLAG_EXCL; walkera0701_parport_cb.irq_func = walkera0701_irq_handler; walkera0701_parport_cb.private = w; w->pardevice = parport_register_dev_model(pp, "walkera0701", &walkera0701_parport_cb, 0); if (!w->pardevice) { pr_err("failed to register parport device\n"); return; } if (parport_negotiate(w->pardevice->port, IEEE1284_MODE_COMPAT)) { pr_err("failed to negotiate parport mode\n"); goto err_unregister_device; } hrtimer_init(&w->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); w->timer.function = timer_handler; w->input_dev = input_allocate_device(); if (!w->input_dev) { pr_err("failed to allocate input device\n"); goto err_unregister_device; } 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->dev.parent = w->parport->dev; 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); if (input_register_device(w->input_dev)) { pr_err("failed to register input device\n"); goto err_free_input_dev; } return; err_free_input_dev: input_free_device(w->input_dev); err_unregister_device: parport_unregister_device(w->pardevice); } static void walkera0701_detach(struct parport *port) { struct walkera_dev *w = &w_dev; if (!w->pardevice || w->parport->number != port->number) return; input_unregister_device(w->input_dev); parport_unregister_device(w->pardevice); w->parport = NULL; } static struct parport_driver walkera0701_parport_driver = { .name = "walkera0701", .match_port = walkera0701_attach, .detach = walkera0701_detach, .devmodel = true, }; static int __init walkera0701_init(void) { return parport_register_driver(&walkera0701_parport_driver); } static void __exit walkera0701_exit(void) { parport_unregister_driver(&walkera0701_parport_driver); } module_init(walkera0701_init); module_exit(walkera0701_exit);