Kernel driver and support software to use a FlySky FS-iA6B 14-channel RC receiver as a general purpose game controller in Linux.
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// SPDX-License-Identifier: GPL-2.0
/*
* FS-iA6B iBus RC receiver driver
*
* Copyright (C) 2018 - 2019 Markus Koch <markus@notsyncing.net>
*/
/*
* This driver will provide 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>
#ifndef SERIO_FSIA6B
#define SERIO_FSIA6B 0x42
#endif
#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);
err = serio_open(serio, drv);
if (err)
goto fail1;
input_dev = input_allocate_device();
if (!input_dev) {
err = -ENOMEM;
goto fail2;
}
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') && (i != IBUS_SERVO_COUNT)) ||
(switch_config[i] < '0') ||
(switch_config[i] > '3')) {
dev_err(&fsia6b->dev->dev,
"Invalid switch configuration supplied for fsia6b.\n");
err = -EINVAL;
goto fail3;
}
for (j = '1'; j <= switch_config[i]; ++j) {
input_set_capability(input_dev, EV_KEY, BTN_0 + sw_id);
sw_id++;
}
}
err = input_register_device(fsia6b->dev);
if (err)
goto fail3;
return 0;
fail3: input_free_device(input_dev);
fail2: serio_close(serio);
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);
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)