drivers/input/joystick/fsia6b.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * FS-iA6B iBus RC receiver driver
   4  *
   5  * This driver provides all 14 channels of the FlySky FS-ia6B RC receiver
   6  * as analog values.
   7  *
   8  * Additionally, the channels can be converted to discrete switch values.
   9  * By default, it is configured for the offical FS-i6 remote control.
  10  * If you use a different hardware configuration, you can configure it
  11  * using the `switch_config` parameter.
  12  */
  13
  14 #include <linux/device.h>
  15 #include <linux/input.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/serio.h>
  19 #include <linux/slab.h>
  20 #include <linux/types.h>
  21
  22 #define DRIVER_DESC             "FS-iA6B iBus RC receiver"
  23
  24 MODULE_AUTHOR("Markus Koch <markus@notsyncing.net>");
  25 MODULE_DESCRIPTION(DRIVER_DESC);
  26 MODULE_LICENSE("GPL");
  27
  28 #define IBUS_SERVO_COUNT        14
  29
  30 static char *switch_config = "00000022320000";
  31 module_param(switch_config, charp, 0444);
  32 MODULE_PARM_DESC(switch_config,
  33                  "Amount of switch positions per channel (14 characters, 0-3)");
  34
  35 static int fsia6b_axes[IBUS_SERVO_COUNT] = {
  36         ABS_X, ABS_Y,
  37         ABS_Z, ABS_RX,
  38         ABS_RY, ABS_RZ,
  39         ABS_HAT0X, ABS_HAT0Y,
  40         ABS_HAT1X, ABS_HAT1Y,
  41         ABS_HAT2X, ABS_HAT2Y,
  42         ABS_HAT3X, ABS_HAT3Y
  43 };
  44
  45 enum ibus_state { SYNC, COLLECT, PROCESS };
  46
  47 struct ibus_packet {
  48         enum ibus_state state;
  49
  50         int offset;
  51         u16 ibuf;
  52         u16 channel[IBUS_SERVO_COUNT];
  53 };
  54
  55 struct fsia6b {
  56         struct input_dev *dev;
  57         struct ibus_packet packet;
  58
  59         char phys[32];
  60 };
  61
  62 static irqreturn_t fsia6b_serio_irq(struct serio *serio,
  63                                     unsigned char data, unsigned int flags)
  64 {
  65         struct fsia6b *fsia6b = serio_get_drvdata(serio);
  66         int i;
  67         int sw_state;
  68         int sw_id = BTN_0;
  69
  70         fsia6b->packet.ibuf = (data << 8) | ((fsia6b->packet.ibuf >> 8) & 0xFF);
  71
  72         switch (fsia6b->packet.state) {
  73         case SYNC:
  74                 if (fsia6b->packet.ibuf == 0x4020)
  75                         fsia6b->packet.state = COLLECT;
  76                 break;
  77
  78         case COLLECT:
  79                 fsia6b->packet.state = PROCESS;
  80                 break;
  81
  82         case PROCESS:
  83                 fsia6b->packet.channel[fsia6b->packet.offset] =
  84                                 fsia6b->packet.ibuf;
  85                 fsia6b->packet.offset++;
  86
  87                 if (fsia6b->packet.offset == IBUS_SERVO_COUNT) {
  88                         fsia6b->packet.offset = 0;
  89                         fsia6b->packet.state = SYNC;
  90                         for (i = 0; i < IBUS_SERVO_COUNT; ++i) {
  91                                 input_report_abs(fsia6b->dev, fsia6b_axes[i],
  92                                                  fsia6b->packet.channel[i]);
  93
  94                                 sw_state = 0;
  95                                 if (fsia6b->packet.channel[i] > 1900)
  96                                         sw_state = 1;
  97                                 else if (fsia6b->packet.channel[i] < 1100)
  98                                         sw_state = 2;
  99
 100                                 switch (switch_config[i]) {
 101                                 case '3':
 102                                         input_report_key(fsia6b->dev,
 103                                                          sw_id++,
 104                                                          sw_state == 0);
 105                                         fallthrough;
 106                                 case '2':
 107                                         input_report_key(fsia6b->dev,
 108                                                          sw_id++,
 109                                                          sw_state == 1);
 110                                         fallthrough;
 111                                 case '1':
 112                                         input_report_key(fsia6b->dev,
 113                                                          sw_id++,
 114                                                          sw_state == 2);
 115                                 }
 116                         }
 117                         input_sync(fsia6b->dev);
 118                 } else {
 119                         fsia6b->packet.state = COLLECT;
 120                 }
 121                 break;
 122         }
 123
 124         return IRQ_HANDLED;
 125 }
 126
 127 static int fsia6b_serio_connect(struct serio *serio, struct serio_driver *drv)
 128 {
 129         struct fsia6b *fsia6b;
 130         struct input_dev *input_dev;
 131         int err;
 132         int i, j;
 133         int sw_id = 0;
 134
 135         fsia6b = kzalloc(sizeof(*fsia6b), GFP_KERNEL);
 136         if (!fsia6b)
 137                 return -ENOMEM;
 138
 139         fsia6b->packet.ibuf = 0;
 140         fsia6b->packet.offset = 0;
 141         fsia6b->packet.state = SYNC;
 142
 143         serio_set_drvdata(serio, fsia6b);
 144
 145         input_dev = input_allocate_device();
 146         if (!input_dev) {
 147                 err = -ENOMEM;
 148                 goto fail1;
 149         }
 150         fsia6b->dev = input_dev;
 151
 152         snprintf(fsia6b->phys, sizeof(fsia6b->phys), "%s/input0", serio->phys);
 153
 154         input_dev->name = DRIVER_DESC;
 155         input_dev->phys = fsia6b->phys;
 156         input_dev->id.bustype = BUS_RS232;
 157         input_dev->id.vendor = SERIO_FSIA6B;
 158         input_dev->id.product = serio->id.id;
 159         input_dev->id.version = 0x0100;
 160         input_dev->dev.parent = &serio->dev;
 161
 162         for (i = 0; i < IBUS_SERVO_COUNT; i++)
 163                 input_set_abs_params(input_dev, fsia6b_axes[i],
 164                                      1000, 2000, 2, 2);
 165
 166         /* Register switch configuration */
 167         for (i = 0; i < IBUS_SERVO_COUNT; i++) {
 168                 if (switch_config[i] < '0' || switch_config[i] > '3') {
 169                         dev_err(&fsia6b->dev->dev,
 170                                 "Invalid switch configuration supplied for fsia6b.\n");
 171                         err = -EINVAL;
 172                         goto fail2;
 173                 }
 174
 175                 for (j = '1'; j <= switch_config[i]; j++) {
 176                         input_set_capability(input_dev, EV_KEY, BTN_0 + sw_id);
 177                         sw_id++;
 178                 }
 179         }
 180
 181         err = serio_open(serio, drv);
 182         if (err)
 183                 goto fail2;
 184
 185         err = input_register_device(fsia6b->dev);
 186         if (err)
 187                 goto fail3;
 188
 189         return 0;
 190
 191 fail3:  serio_close(serio);
 192 fail2:  input_free_device(input_dev);
 193 fail1:  serio_set_drvdata(serio, NULL);
 194         kfree(fsia6b);
 195         return err;
 196 }
 197
 198 static void fsia6b_serio_disconnect(struct serio *serio)
 199 {
 200         struct fsia6b *fsia6b = serio_get_drvdata(serio);
 201
 202         serio_close(serio);
 203         serio_set_drvdata(serio, NULL);
 204         input_unregister_device(fsia6b->dev);
 205         kfree(fsia6b);
 206 }
 207
 208 static const struct serio_device_id fsia6b_serio_ids[] = {
 209         {
 210                 .type   = SERIO_RS232,
 211                 .proto  = SERIO_FSIA6B,
 212                 .id     = SERIO_ANY,
 213                 .extra  = SERIO_ANY,
 214         },
 215         { 0 }
 216 };
 217
 218 MODULE_DEVICE_TABLE(serio, fsia6b_serio_ids);
 219
 220 static struct serio_driver fsia6b_serio_drv = {
 221         .driver         = {
 222                 .name   = "fsia6b"
 223         },
 224         .description    = DRIVER_DESC,
 225         .id_table       = fsia6b_serio_ids,
 226         .interrupt      = fsia6b_serio_irq,
 227         .connect        = fsia6b_serio_connect,
 228         .disconnect     = fsia6b_serio_disconnect
 229 };
 230
 231 module_serio_driver(fsia6b_serio_drv)