--- /dev/null
+/*
+ * derived from "twidjoy.c"
+ *
+ * Copyright (c) 2008 Martin Kebert
+ * Copyright (c) 2001 Arndt Schoenewald
+ * Copyright (c) 2000-2001 Vojtech Pavlik
+ * Copyright (c) 2000 Mark Fletcher
+ *
+ */
+
+/*
+ * Driver to use 4CH RC transmitter using Zhen Hua 5-byte protocol (Walkera Lama,
+ * EasyCopter etc.) as a joystick under Linux.
+ *
+ * RC transmitters using Zhen Hua 5-byte protocol are cheap four channels
+ * transmitters for control a RC planes or RC helicopters with possibility to
+ * connect on a serial port.
+ * Data coming from transmitter is in this order:
+ * 1. byte = synchronisation byte
+ * 2. byte = X axis
+ * 3. byte = Y axis
+ * 4. byte = RZ axis
+ * 5. byte = Z axis
+ * (and this is repeated)
+ *
+ * For questions or feedback regarding this driver module please contact:
+ * Martin Kebert <gkmarty@gmail.com> - but I am not a C-programmer nor kernel
+ * coder :-(
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/serio.h>
+
+#define DRIVER_DESC "RC transmitter with 5-byte Zhen Hua protocol joystick driver"
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+/*
+ * Constants.
+ */
+
+#define ZHENHUA_MAX_LENGTH 5
+
+/*
+ * Zhen Hua data.
+ */
+
+struct zhenhua {
+ struct input_dev *dev;
+ int idx;
+ unsigned char data[ZHENHUA_MAX_LENGTH];
+ char phys[32];
+};
+
+
+/* bits in all incoming bytes needs to be "reversed" */
+static int zhenhua_bitreverse(int x)
+{
+ x = ((x & 0xaa) >> 1) | ((x & 0x55) << 1);
+ x = ((x & 0xcc) >> 2) | ((x & 0x33) << 2);
+ x = ((x & 0xf0) >> 4) | ((x & 0x0f) << 4);
+ return x;
+}
+
+/*
+ * zhenhua_process_packet() decodes packets the driver receives from the
+ * RC transmitter. It updates the data accordingly.
+ */
+
+static void zhenhua_process_packet(struct zhenhua *zhenhua)
+{
+ struct input_dev *dev = zhenhua->dev;
+ unsigned char *data = zhenhua->data;
+
+ input_report_abs(dev, ABS_Y, data[1]);
+ input_report_abs(dev, ABS_X, data[2]);
+ input_report_abs(dev, ABS_RZ, data[3]);
+ input_report_abs(dev, ABS_Z, data[4]);
+
+ input_sync(dev);
+}
+
+/*
+ * zhenhua_interrupt() is called by the low level driver when characters
+ * are ready for us. We then buffer them for further processing, or call the
+ * packet processing routine.
+ */
+
+static irqreturn_t zhenhua_interrupt(struct serio *serio, unsigned char data, unsigned int flags)
+{
+ struct zhenhua *zhenhua = serio_get_drvdata(serio);
+
+ /* All Zhen Hua packets are 5 bytes. The fact that the first byte
+ * is allways 0xf7 and all others are in range 0x32 - 0xc8 (50-200)
+ * can be used to check and regain sync. */
+
+ if (data == 0xef)
+ zhenhua->idx = 0; /* this byte starts a new packet */
+ else if (zhenhua->idx == 0)
+ return IRQ_HANDLED; /* wrong MSB -- ignore this byte */
+
+ if (zhenhua->idx < ZHENHUA_MAX_LENGTH)
+ zhenhua->data[zhenhua->idx++] = zhenhua_bitreverse(data);
+
+ if (zhenhua->idx == ZHENHUA_MAX_LENGTH) {
+ zhenhua_process_packet(zhenhua);
+ zhenhua->idx = 0;
+ }
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * zhenhua_disconnect() is the opposite of zhenhua_connect()
+ */
+
+static void zhenhua_disconnect(struct serio *serio)
+{
+ struct zhenhua *zhenhua = serio_get_drvdata(serio);
+
+ serio_close(serio);
+ serio_set_drvdata(serio, NULL);
+ input_unregister_device(zhenhua->dev);
+ kfree(zhenhua);
+}
+
+/*
+ * zhenhua_connect() is the routine that is called when someone adds a
+ * new serio device. It looks for the Twiddler, and if found, registers
+ * it as an input device.
+ */
+
+static int zhenhua_connect(struct serio *serio, struct serio_driver *drv)
+{
+ struct zhenhua *zhenhua;
+ struct input_dev *input_dev;
+ int err = -ENOMEM;
+
+ zhenhua = kzalloc(sizeof(struct zhenhua), GFP_KERNEL);
+ input_dev = input_allocate_device();
+ if (!zhenhua || !input_dev)
+ goto fail1;
+
+ zhenhua->dev = input_dev;
+ snprintf(zhenhua->phys, sizeof(zhenhua->phys), "%s/input0", serio->phys);
+
+ input_dev->name = "Zhen Hua 5-byte device";
+ input_dev->phys = zhenhua->phys;
+ input_dev->id.bustype = BUS_RS232;
+ input_dev->id.vendor = SERIO_ZHENHUA;
+ input_dev->id.product = 0x0001;
+ input_dev->id.version = 0x0100;
+ input_dev->dev.parent = &serio->dev;
+
+ input_dev->evbit[0] = BIT(EV_ABS);
+ input_set_abs_params(input_dev, ABS_X, 50, 200, 0, 0);
+ input_set_abs_params(input_dev, ABS_Y, 50, 200, 0, 0);
+ input_set_abs_params(input_dev, ABS_Z, 50, 200, 0, 0);
+ input_set_abs_params(input_dev, ABS_RZ, 50, 200, 0, 0);
+
+ serio_set_drvdata(serio, zhenhua);
+
+ err = serio_open(serio, drv);
+ if (err)
+ goto fail2;
+
+ err = input_register_device(zhenhua->dev);
+ if (err)
+ goto fail3;
+
+ return 0;
+
+ fail3: serio_close(serio);
+ fail2: serio_set_drvdata(serio, NULL);
+ fail1: input_free_device(input_dev);
+ kfree(zhenhua);
+ return err;
+}
+
+/*
+ * The serio driver structure.
+ */
+
+static struct serio_device_id zhenhua_serio_ids[] = {
+ {
+ .type = SERIO_RS232,
+ .proto = SERIO_ZHENHUA,
+ .id = SERIO_ANY,
+ .extra = SERIO_ANY,
+ },
+ { 0 }
+};
+
+MODULE_DEVICE_TABLE(serio, zhenhua_serio_ids);
+
+static struct serio_driver zhenhua_drv = {
+ .driver = {
+ .name = "zhenhua",
+ },
+ .description = DRIVER_DESC,
+ .id_table = zhenhua_serio_ids,
+ .interrupt = zhenhua_interrupt,
+ .connect = zhenhua_connect,
+ .disconnect = zhenhua_disconnect,
+};
+
+module_serio_driver(zhenhua_drv);
Code Review / kvmfornfv.git / blobdiff