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