2 * derived from "twidjoy.c"
4 * Copyright (c) 2008 Martin Kebert
5 * Copyright (c) 2001 Arndt Schoenewald
6 * Copyright (c) 2000-2001 Vojtech Pavlik
7 * Copyright (c) 2000 Mark Fletcher
12 * Driver to use 4CH RC transmitter using Zhen Hua 5-byte protocol (Walkera Lama,
13 * EasyCopter etc.) as a joystick under Linux.
15 * RC transmitters using Zhen Hua 5-byte protocol are cheap four channels
16 * transmitters for control a RC planes or RC helicopters with possibility to
17 * connect on a serial port.
18 * Data coming from transmitter is in this order:
19 * 1. byte = synchronisation byte
24 * (and this is repeated)
26 * For questions or feedback regarding this driver module please contact:
27 * Martin Kebert <gkmarty@gmail.com> - but I am not a C-programmer nor kernel
32 * This program is free software; you can redistribute it and/or modify
33 * it under the terms of the GNU General Public License as published by
34 * the Free Software Foundation; either version 2 of the License, or
35 * (at your option) any later version.
37 * This program is distributed in the hope that it will be useful,
38 * but WITHOUT ANY WARRANTY; without even the implied warranty of
39 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
40 * GNU General Public License for more details.
42 * You should have received a copy of the GNU General Public License
43 * along with this program; if not, write to the Free Software
44 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
47 #include <linux/kernel.h>
48 #include <linux/module.h>
49 #include <linux/slab.h>
50 #include <linux/bitrev.h>
51 #include <linux/input.h>
52 #include <linux/serio.h>
54 #define DRIVER_DESC "RC transmitter with 5-byte Zhen Hua protocol joystick driver"
56 MODULE_DESCRIPTION(DRIVER_DESC
);
57 MODULE_LICENSE("GPL");
63 #define ZHENHUA_MAX_LENGTH 5
70 struct input_dev
*dev
;
72 unsigned char data
[ZHENHUA_MAX_LENGTH
];
77 * zhenhua_process_packet() decodes packets the driver receives from the
78 * RC transmitter. It updates the data accordingly.
81 static void zhenhua_process_packet(struct zhenhua
*zhenhua
)
83 struct input_dev
*dev
= zhenhua
->dev
;
84 unsigned char *data
= zhenhua
->data
;
86 input_report_abs(dev
, ABS_Y
, data
[1]);
87 input_report_abs(dev
, ABS_X
, data
[2]);
88 input_report_abs(dev
, ABS_RZ
, data
[3]);
89 input_report_abs(dev
, ABS_Z
, data
[4]);
95 * zhenhua_interrupt() is called by the low level driver when characters
96 * are ready for us. We then buffer them for further processing, or call the
97 * packet processing routine.
100 static irqreturn_t
zhenhua_interrupt(struct serio
*serio
, unsigned char data
, unsigned int flags
)
102 struct zhenhua
*zhenhua
= serio_get_drvdata(serio
);
104 /* All Zhen Hua packets are 5 bytes. The fact that the first byte
105 * is allways 0xf7 and all others are in range 0x32 - 0xc8 (50-200)
106 * can be used to check and regain sync. */
109 zhenhua
->idx
= 0; /* this byte starts a new packet */
110 else if (zhenhua
->idx
== 0)
111 return IRQ_HANDLED
; /* wrong MSB -- ignore this byte */
113 if (zhenhua
->idx
< ZHENHUA_MAX_LENGTH
)
114 zhenhua
->data
[zhenhua
->idx
++] = bitrev8(data
);
116 if (zhenhua
->idx
== ZHENHUA_MAX_LENGTH
) {
117 zhenhua_process_packet(zhenhua
);
125 * zhenhua_disconnect() is the opposite of zhenhua_connect()
128 static void zhenhua_disconnect(struct serio
*serio
)
130 struct zhenhua
*zhenhua
= serio_get_drvdata(serio
);
133 serio_set_drvdata(serio
, NULL
);
134 input_unregister_device(zhenhua
->dev
);
139 * zhenhua_connect() is the routine that is called when someone adds a
140 * new serio device. It looks for the Twiddler, and if found, registers
141 * it as an input device.
144 static int zhenhua_connect(struct serio
*serio
, struct serio_driver
*drv
)
146 struct zhenhua
*zhenhua
;
147 struct input_dev
*input_dev
;
150 zhenhua
= kzalloc(sizeof(struct zhenhua
), GFP_KERNEL
);
151 input_dev
= input_allocate_device();
152 if (!zhenhua
|| !input_dev
)
155 zhenhua
->dev
= input_dev
;
156 snprintf(zhenhua
->phys
, sizeof(zhenhua
->phys
), "%s/input0", serio
->phys
);
158 input_dev
->name
= "Zhen Hua 5-byte device";
159 input_dev
->phys
= zhenhua
->phys
;
160 input_dev
->id
.bustype
= BUS_RS232
;
161 input_dev
->id
.vendor
= SERIO_ZHENHUA
;
162 input_dev
->id
.product
= 0x0001;
163 input_dev
->id
.version
= 0x0100;
164 input_dev
->dev
.parent
= &serio
->dev
;
166 input_dev
->evbit
[0] = BIT(EV_ABS
);
167 input_set_abs_params(input_dev
, ABS_X
, 50, 200, 0, 0);
168 input_set_abs_params(input_dev
, ABS_Y
, 50, 200, 0, 0);
169 input_set_abs_params(input_dev
, ABS_Z
, 50, 200, 0, 0);
170 input_set_abs_params(input_dev
, ABS_RZ
, 50, 200, 0, 0);
172 serio_set_drvdata(serio
, zhenhua
);
174 err
= serio_open(serio
, drv
);
178 err
= input_register_device(zhenhua
->dev
);
184 fail3
: serio_close(serio
);
185 fail2
: serio_set_drvdata(serio
, NULL
);
186 fail1
: input_free_device(input_dev
);
192 * The serio driver structure.
195 static const struct serio_device_id zhenhua_serio_ids
[] = {
198 .proto
= SERIO_ZHENHUA
,
205 MODULE_DEVICE_TABLE(serio
, zhenhua_serio_ids
);
207 static struct serio_driver zhenhua_drv
= {
211 .description
= DRIVER_DESC
,
212 .id_table
= zhenhua_serio_ids
,
213 .interrupt
= zhenhua_interrupt
,
214 .connect
= zhenhua_connect
,
215 .disconnect
= zhenhua_disconnect
,
218 module_serio_driver(zhenhua_drv
);