// SPDX-License-Identifier: GPL-2.0 /* * FS-iA6B iBus RC receiver driver * * This driver provides all 14 channels of the FlySky FS-ia6B RC receiver * as analog values. * * Additionally, the channels can be converted to discrete switch values. * By default, it is configured for the offical FS-i6 remote control. * If you use a different hardware configuration, you can configure it * using the `switch_config` parameter. */ #include <linux/device.h> #include <linux/input.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/serio.h> #include <linux/slab.h> #include <linux/types.h> #define DRIVER_DESC "FS-iA6B iBus RC receiver" MODULE_AUTHOR("Markus Koch <markus@notsyncing.net>"); MODULE_DESCRIPTION(DRIVER_DESC); MODULE_LICENSE("GPL"); #define IBUS_SERVO_COUNT 14 static char *switch_config = "00000022320000"; module_param(switch_config, charp, 0444); MODULE_PARM_DESC(switch_config, "Amount of switch positions per channel (14 characters, 0-3)"); static int fsia6b_axes[IBUS_SERVO_COUNT] = { ABS_X, ABS_Y, ABS_Z, ABS_RX, ABS_RY, ABS_RZ, ABS_HAT0X, ABS_HAT0Y, ABS_HAT1X, ABS_HAT1Y, ABS_HAT2X, ABS_HAT2Y, ABS_HAT3X, ABS_HAT3Y }; enum ibus_state { SYNC, COLLECT, PROCESS }; struct ibus_packet { enum ibus_state state; int offset; u16 ibuf; u16 channel[IBUS_SERVO_COUNT]; }; struct fsia6b { struct input_dev *dev; struct ibus_packet packet; char phys[32]; }; static irqreturn_t fsia6b_serio_irq(struct serio *serio, unsigned char data, unsigned int flags) { struct fsia6b *fsia6b = serio_get_drvdata(serio); int i; int sw_state; int sw_id = BTN_0; fsia6b->packet.ibuf = (data << 8) | ((fsia6b->packet.ibuf >> 8) & 0xFF); switch (fsia6b->packet.state) { case SYNC: if (fsia6b->packet.ibuf == 0x4020) fsia6b->packet.state = COLLECT; break; case COLLECT: fsia6b->packet.state = PROCESS; break; case PROCESS: fsia6b->packet.channel[fsia6b->packet.offset] = fsia6b->packet.ibuf; fsia6b->packet.offset++; if (fsia6b->packet.offset == IBUS_SERVO_COUNT) { fsia6b->packet.offset = 0; fsia6b->packet.state = SYNC; for (i = 0; i < IBUS_SERVO_COUNT; ++i) { input_report_abs(fsia6b->dev, fsia6b_axes[i], fsia6b->packet.channel[i]); sw_state = 0; if (fsia6b->packet.channel[i] > 1900) sw_state = 1; else if (fsia6b->packet.channel[i] < 1100) sw_state = 2; switch (switch_config[i]) { case '3': input_report_key(fsia6b->dev, sw_id++, sw_state == 0); /* fall-through */ case '2': input_report_key(fsia6b->dev, sw_id++, sw_state == 1); /* fall-through */ case '1': input_report_key(fsia6b->dev, sw_id++, sw_state == 2); } } input_sync(fsia6b->dev); } else { fsia6b->packet.state = COLLECT; } break; } return IRQ_HANDLED; } static int fsia6b_serio_connect(struct serio *serio, struct serio_driver *drv) { struct fsia6b *fsia6b; struct input_dev *input_dev; int err; int i, j; int sw_id = 0; fsia6b = kzalloc(sizeof(*fsia6b), GFP_KERNEL); if (!fsia6b) return -ENOMEM; fsia6b->packet.ibuf = 0; fsia6b->packet.offset = 0; fsia6b->packet.state = SYNC; serio_set_drvdata(serio, fsia6b); input_dev = input_allocate_device(); if (!input_dev) { err = -ENOMEM; goto fail1; } fsia6b->dev = input_dev; snprintf(fsia6b->phys, sizeof(fsia6b->phys), "%s/input0", serio->phys); input_dev->name = DRIVER_DESC; input_dev->phys = fsia6b->phys; input_dev->id.bustype = BUS_RS232; input_dev->id.vendor = SERIO_FSIA6B; input_dev->id.product = serio->id.id; input_dev->id.version = 0x0100; input_dev->dev.parent = &serio->dev; for (i = 0; i < IBUS_SERVO_COUNT; i++) input_set_abs_params(input_dev, fsia6b_axes[i], 1000, 2000, 2, 2); /* Register switch configuration */ for (i = 0; i < IBUS_SERVO_COUNT; i++) { if (switch_config[i] < '0' || switch_config[i] > '3') { dev_err(&fsia6b->dev->dev, "Invalid switch configuration supplied for fsia6b.\n"); err = -EINVAL; goto fail2; } for (j = '1'; j <= switch_config[i]; j++) { input_set_capability(input_dev, EV_KEY, BTN_0 + sw_id); sw_id++; } } err = serio_open(serio, drv); if (err) goto fail2; err = input_register_device(fsia6b->dev); if (err) goto fail3; return 0; fail3: serio_close(serio); fail2: input_free_device(input_dev); fail1: serio_set_drvdata(serio, NULL); kfree(fsia6b); return err; } static void fsia6b_serio_disconnect(struct serio *serio) { struct fsia6b *fsia6b = serio_get_drvdata(serio); serio_close(serio); serio_set_drvdata(serio, NULL); input_unregister_device(fsia6b->dev); kfree(fsia6b); } static const struct serio_device_id fsia6b_serio_ids[] = { { .type = SERIO_RS232, .proto = SERIO_FSIA6B, .id = SERIO_ANY, .extra = SERIO_ANY, }, { 0 } }; MODULE_DEVICE_TABLE(serio, fsia6b_serio_ids); static struct serio_driver fsia6b_serio_drv = { .driver = { .name = "fsia6b" }, .description = DRIVER_DESC, .id_table = fsia6b_serio_ids, .interrupt = fsia6b_serio_irq, .connect = fsia6b_serio_connect, .disconnect = fsia6b_serio_disconnect }; module_serio_driver(fsia6b_serio_drv)