1 files changed, 310 insertions, 0 deletions

diff --git a/drivers/input/joystick/walkera0701.c b/drivers/input/joystick/walkera0701.c
new file mode 100644
index 000000000..56abc8c6c
--- /dev/null
+++ b/drivers/input/joystick/walkera0701.c
@@ -0,0 +1,310 @@
+// 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,
+	.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);