Martin Kebert | 3e24e2b | 2008-03-10 13:40:36 +0100 | [diff] [blame] | 1 | /* |
| 2 | * derived from "twidjoy.c" |
| 3 | * |
| 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 |
| 8 | * |
| 9 | */ |
| 10 | |
| 11 | /* |
| 12 | * Driver to use 4CH RC transmitter using Zhen Hua 5-byte protocol (Walkera Lama, |
| 13 | * EasyCopter etc.) as a joystick under Linux. |
| 14 | * |
| 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 |
| 20 | * 2. byte = X axis |
| 21 | * 3. byte = Y axis |
| 22 | * 4. byte = RZ axis |
| 23 | * 5. byte = Z axis |
| 24 | * (and this is repeated) |
| 25 | * |
| 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 |
| 28 | * coder :-( |
| 29 | */ |
| 30 | |
| 31 | /* |
| 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. |
| 36 | * |
| 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. |
| 41 | * |
| 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 |
| 45 | */ |
| 46 | |
| 47 | #include <linux/kernel.h> |
| 48 | #include <linux/module.h> |
| 49 | #include <linux/slab.h> |
| 50 | #include <linux/input.h> |
| 51 | #include <linux/serio.h> |
| 52 | #include <linux/init.h> |
| 53 | |
| 54 | #define DRIVER_DESC "RC transmitter with 5-byte Zhen Hua protocol joystick driver" |
| 55 | |
| 56 | MODULE_DESCRIPTION(DRIVER_DESC); |
| 57 | MODULE_LICENSE("GPL"); |
| 58 | |
| 59 | /* |
| 60 | * Constants. |
| 61 | */ |
| 62 | |
| 63 | #define ZHENHUA_MAX_LENGTH 5 |
| 64 | |
| 65 | /* |
| 66 | * Zhen Hua data. |
| 67 | */ |
| 68 | |
| 69 | struct zhenhua { |
| 70 | struct input_dev *dev; |
| 71 | int idx; |
| 72 | unsigned char data[ZHENHUA_MAX_LENGTH]; |
| 73 | char phys[32]; |
| 74 | }; |
| 75 | |
| 76 | |
| 77 | /* bits in all incoming bytes needs to be "reversed" */ |
| 78 | static int zhenhua_bitreverse(int x) |
| 79 | { |
| 80 | x = ((x & 0xaa) >> 1) | ((x & 0x55) << 1); |
| 81 | x = ((x & 0xcc) >> 2) | ((x & 0x33) << 2); |
| 82 | x = ((x & 0xf0) >> 4) | ((x & 0x0f) << 4); |
| 83 | return x; |
| 84 | } |
| 85 | |
| 86 | /* |
| 87 | * zhenhua_process_packet() decodes packets the driver receives from the |
| 88 | * RC transmitter. It updates the data accordingly. |
| 89 | */ |
| 90 | |
| 91 | static void zhenhua_process_packet(struct zhenhua *zhenhua) |
| 92 | { |
| 93 | struct input_dev *dev = zhenhua->dev; |
| 94 | unsigned char *data = zhenhua->data; |
| 95 | |
| 96 | input_report_abs(dev, ABS_Y, data[1]); |
| 97 | input_report_abs(dev, ABS_X, data[2]); |
| 98 | input_report_abs(dev, ABS_RZ, data[3]); |
| 99 | input_report_abs(dev, ABS_Z, data[4]); |
| 100 | |
| 101 | input_sync(dev); |
| 102 | } |
| 103 | |
| 104 | /* |
| 105 | * zhenhua_interrupt() is called by the low level driver when characters |
| 106 | * are ready for us. We then buffer them for further processing, or call the |
| 107 | * packet processing routine. |
| 108 | */ |
| 109 | |
| 110 | static irqreturn_t zhenhua_interrupt(struct serio *serio, unsigned char data, unsigned int flags) |
| 111 | { |
| 112 | struct zhenhua *zhenhua = serio_get_drvdata(serio); |
| 113 | |
| 114 | /* All Zhen Hua packets are 5 bytes. The fact that the first byte |
| 115 | * is allways 0xf7 and all others are in range 0x32 - 0xc8 (50-200) |
| 116 | * can be used to check and regain sync. */ |
| 117 | |
| 118 | if (data == 0xef) |
| 119 | zhenhua->idx = 0; /* this byte starts a new packet */ |
| 120 | else if (zhenhua->idx == 0) |
| 121 | return IRQ_HANDLED; /* wrong MSB -- ignore this byte */ |
| 122 | |
| 123 | if (zhenhua->idx < ZHENHUA_MAX_LENGTH) |
| 124 | zhenhua->data[zhenhua->idx++] = zhenhua_bitreverse(data); |
| 125 | |
| 126 | if (zhenhua->idx == ZHENHUA_MAX_LENGTH) { |
| 127 | zhenhua_process_packet(zhenhua); |
| 128 | zhenhua->idx = 0; |
| 129 | } |
| 130 | |
| 131 | return IRQ_HANDLED; |
| 132 | } |
| 133 | |
| 134 | /* |
| 135 | * zhenhua_disconnect() is the opposite of zhenhua_connect() |
| 136 | */ |
| 137 | |
| 138 | static void zhenhua_disconnect(struct serio *serio) |
| 139 | { |
| 140 | struct zhenhua *zhenhua = serio_get_drvdata(serio); |
| 141 | |
| 142 | serio_close(serio); |
| 143 | serio_set_drvdata(serio, NULL); |
| 144 | input_unregister_device(zhenhua->dev); |
| 145 | kfree(zhenhua); |
| 146 | } |
| 147 | |
| 148 | /* |
| 149 | * zhenhua_connect() is the routine that is called when someone adds a |
| 150 | * new serio device. It looks for the Twiddler, and if found, registers |
| 151 | * it as an input device. |
| 152 | */ |
| 153 | |
| 154 | static int zhenhua_connect(struct serio *serio, struct serio_driver *drv) |
| 155 | { |
| 156 | struct zhenhua *zhenhua; |
| 157 | struct input_dev *input_dev; |
| 158 | int err = -ENOMEM; |
| 159 | |
| 160 | zhenhua = kzalloc(sizeof(struct zhenhua), GFP_KERNEL); |
| 161 | input_dev = input_allocate_device(); |
| 162 | if (!zhenhua || !input_dev) |
| 163 | goto fail1; |
| 164 | |
| 165 | zhenhua->dev = input_dev; |
| 166 | snprintf(zhenhua->phys, sizeof(zhenhua->phys), "%s/input0", serio->phys); |
| 167 | |
| 168 | input_dev->name = "Zhen Hua 5-byte device"; |
| 169 | input_dev->phys = zhenhua->phys; |
| 170 | input_dev->id.bustype = BUS_RS232; |
| 171 | input_dev->id.vendor = SERIO_ZHENHUA; |
| 172 | input_dev->id.product = 0x0001; |
| 173 | input_dev->id.version = 0x0100; |
| 174 | input_dev->dev.parent = &serio->dev; |
| 175 | |
| 176 | input_dev->evbit[0] = BIT(EV_ABS); |
| 177 | input_set_abs_params(input_dev, ABS_X, 50, 200, 0, 0); |
| 178 | input_set_abs_params(input_dev, ABS_Y, 50, 200, 0, 0); |
| 179 | input_set_abs_params(input_dev, ABS_Z, 50, 200, 0, 0); |
| 180 | input_set_abs_params(input_dev, ABS_RZ, 50, 200, 0, 0); |
| 181 | |
| 182 | serio_set_drvdata(serio, zhenhua); |
| 183 | |
| 184 | err = serio_open(serio, drv); |
| 185 | if (err) |
| 186 | goto fail2; |
| 187 | |
| 188 | err = input_register_device(zhenhua->dev); |
| 189 | if (err) |
| 190 | goto fail3; |
| 191 | |
| 192 | return 0; |
| 193 | |
| 194 | fail3: serio_close(serio); |
| 195 | fail2: serio_set_drvdata(serio, NULL); |
| 196 | fail1: input_free_device(input_dev); |
| 197 | kfree(zhenhua); |
| 198 | return err; |
| 199 | } |
| 200 | |
| 201 | /* |
| 202 | * The serio driver structure. |
| 203 | */ |
| 204 | |
| 205 | static struct serio_device_id zhenhua_serio_ids[] = { |
| 206 | { |
| 207 | .type = SERIO_RS232, |
| 208 | .proto = SERIO_ZHENHUA, |
| 209 | .id = SERIO_ANY, |
| 210 | .extra = SERIO_ANY, |
| 211 | }, |
| 212 | { 0 } |
| 213 | }; |
| 214 | |
| 215 | MODULE_DEVICE_TABLE(serio, zhenhua_serio_ids); |
| 216 | |
| 217 | static struct serio_driver zhenhua_drv = { |
| 218 | .driver = { |
| 219 | .name = "zhenhua", |
| 220 | }, |
| 221 | .description = DRIVER_DESC, |
| 222 | .id_table = zhenhua_serio_ids, |
| 223 | .interrupt = zhenhua_interrupt, |
| 224 | .connect = zhenhua_connect, |
| 225 | .disconnect = zhenhua_disconnect, |
| 226 | }; |
| 227 | |
| 228 | /* |
| 229 | * The functions for inserting/removing us as a module. |
| 230 | */ |
| 231 | |
| 232 | static int __init zhenhua_init(void) |
| 233 | { |
| 234 | return serio_register_driver(&zhenhua_drv); |
| 235 | } |
| 236 | |
| 237 | static void __exit zhenhua_exit(void) |
| 238 | { |
| 239 | serio_unregister_driver(&zhenhua_drv); |
| 240 | } |
| 241 | |
| 242 | module_init(zhenhua_init); |
| 243 | module_exit(zhenhua_exit); |