drivers/input/joystick/walkera0701.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *  Parallel port to Walkera WK-0701 TX joystick
  *
  *  Copyright (c) 2008 Peter Popovec
  *
  *  More about driver:  <file:Documentation/input/devices/walkera0701.rst>
  */


 #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, 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,
 };

 module_parport_driver(walkera0701_parport_driver);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Parallel port to Walkera WK-0701 TX joystick
	*
	* Copyright (c) 2008 Peter Popovec
	*
	* More about driver: <file:Documentation/input/devices/walkera0701.rst>
	*/


	#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, 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,
	};

	module_parport_driver(walkera0701_parport_driver);