diff options
| -rw-r--r-- | Documentation/input/walkera0701.txt | 109 | ||||
| -rw-r--r-- | drivers/input/joystick/Kconfig | 12 | ||||
| -rw-r--r-- | drivers/input/joystick/Makefile | 1 | ||||
| -rw-r--r-- | drivers/input/joystick/walkera0701.c | 292 |
4 files changed, 414 insertions, 0 deletions
diff --git a/Documentation/input/walkera0701.txt b/Documentation/input/walkera0701.txt new file mode 100644 index 0000000..8f4289e --- /dev/null +++ b/Documentation/input/walkera0701.txt @@ -0,0 +1,109 @@ + +Walkera WK-0701 transmitter is supplied with a ready to fly Walkera +helicopters such as HM36, HM37, HM60. The walkera0701 module enables to use +this transmitter as joystick + +Devel homepage and download: +http://zub.fei.tuke.sk/walkera-wk0701/ + +or use cogito: +cg-clone http://zub.fei.tuke.sk/GIT/walkera0701-joystick + + +Connecting to PC: + +At back side of transmitter S-video connector can be found. Modulation +pulses from processor to HF part can be found at pin 2 of this connector, +pin 3 is GND. Between pin 3 and CPU 5k6 resistor can be found. To get +modulation pulses to PC, signal pulses must be amplified. + +Cable: (walkera TX to parport) + +Walkera WK-0701 TX S-VIDEO connector: + (back side of TX) + __ __ S-video: canon25 + / |_| \ pin 2 (signal) NPN parport + / O 4 3 O \ pin 3 (GND) LED ________________ 10 ACK + ( O 2 1 O ) | C + \ ___ / 2 ________________________|\|_____|/ + | [___] | |/| B |\ + ------- 3 __________________________________|________________ 25 GND + E + + +I use green LED and BC109 NPN transistor. + +Software: + +Build kernel with walkera0701 module. Module walkera0701 need exclusive +access to parport, modules like lp must be unloaded before loading +walkera0701 module, check dmesg for error messages. Connect TX to PC by +cable and run jstest /dev/input/js0 to see values from TX. If no value can +be changed by TX "joystick", check output from /proc/interrupts. Value for +(usually irq7) parport must increase if TX is on. + + + +Technical details: + +Driver use interrupt from parport ACK input bit to measure pulse length +using hrtimers. + +Frame format: +Based on walkera WK-0701 PCM Format description by Shaul Eizikovich. +(downloaded from http://www.smartpropoplus.com/Docs/Walkera_Wk-0701_PCM.pdf) + +Signal pulses: + (ANALOG) + SYNC BIN OCT + +---------+ +------+ + | | | | +--+ +------+ +--- + +Frame: + SYNC , BIN1, OCT1, BIN2, OCT2 ... BIN24, OCT24, BIN25, next frame SYNC .. + +pulse length: + Binary values: Analog octal values: + + 288 uS Binary 0 318 uS 000 + 438 uS Binary 1 398 uS 001 + 478 uS 010 + 558 uS 011 + 638 uS 100 + 1306 uS SYNC 718 uS 101 + 798 uS 110 + 878 uS 111 + +24 bin+oct values + 1 bin value = 24*4+1 bits = 97 bits + +(Warning, pulses on ACK ar inverted by transistor, irq is rised up on sync +to bin change or octal value to bin change). + +Binary data representations: + +One binary and octal value can be grouped to nibble. 24 nibbles + one binary +values can be sampled between sync pulses. + +Values for first four channels (analog joystick values) can be found in +first 10 nibbles. Analog value is represented by one sign bit and 9 bit +absolute binary value. (10 bits per channel). Next nibble is checksum for +first ten nibbles. + +Next nibbles 12 .. 21 represents four channels (not all channels can be +directly controlled from TX). Binary representations ar the same as in first +four channels. In nibbles 22 and 23 is a special magic number. Nibble 24 is +checksum for nibbles 12..23. + +After last octal value for nibble 24 and next sync pulse one additional +binary value can be sampled. This bit and magic number is not used in +software driver. Some details about this magic numbers can be found in +Walkera_Wk-0701_PCM.pdf. + +Checksum calculation: + +Summary of octal values in nibbles must be same as octal value in checksum +nibble (only first 3 bits are used). Binary value for checksum nibble is +calculated by sum of binary values in checked nibbles + sum of octal values +in checked nibbles divided by 8. Only bit 0 of this sum is used. + diff --git a/drivers/input/joystick/Kconfig b/drivers/input/joystick/Kconfig index be5c14a..268dd3f 100644 --- a/drivers/input/joystick/Kconfig +++ b/drivers/input/joystick/Kconfig @@ -294,4 +294,16 @@ config JOYSTICK_XPAD_LEDS This option enables support for the LED which surrounds the Big X on XBox 360 controller. +config JOYSTICK_WALKERA0701 + tristate "Walkera WK-0701 RC transmitter" + depends on HIGH_RES_TIMERS && PARPORT + help + Say Y or M here if you have a Walkera WK-0701 transmitter which is + supplied with a ready to fly Walkera helicopters such as HM36, + HM37, HM60 and want to use it via parport as a joystick. More + information is available: <file:Documentation/input/walkera0701.txt> + + To compile this driver as a module, choose M here: the + module will be called walkera0701. + endif diff --git a/drivers/input/joystick/Makefile b/drivers/input/joystick/Makefile index fdbf8c4..7230362 100644 --- a/drivers/input/joystick/Makefile +++ b/drivers/input/joystick/Makefile @@ -29,4 +29,5 @@ obj-$(CONFIG_JOYSTICK_TWIDJOY) += twidjoy.o obj-$(CONFIG_JOYSTICK_WARRIOR) += warrior.o obj-$(CONFIG_JOYSTICK_XPAD) += xpad.o obj-$(CONFIG_JOYSTICK_ZHENHUA) += zhenhua.o +obj-$(CONFIG_JOYSTICK_WALKERA0701) += walkera0701.o diff --git a/drivers/input/joystick/walkera0701.c b/drivers/input/joystick/walkera0701.c new file mode 100644 index 0000000..4dfa1ee --- /dev/null +++ b/drivers/input/joystick/walkera0701.c @@ -0,0 +1,292 @@ +/* + * 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); |
