diff options
Diffstat (limited to 'drivers/input/joystick/zhenhua.c')
| -rw-r--r-- | drivers/input/joystick/zhenhua.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/drivers/input/joystick/zhenhua.c b/drivers/input/joystick/zhenhua.c new file mode 100644 index 000000000..3f2460e2b --- /dev/null +++ b/drivers/input/joystick/zhenhua.c @@ -0,0 +1,202 @@ +// 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); |