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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 | // SPDX-License-Identifier: GPL-2.0-or-later /* * 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 :-( */ /* */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/bitrev.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]; }; /* * 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++] = bitrev8(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 const 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); |