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205 lines
4.9 KiB
205 lines
4.9 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* derived from "twidjoy.c" |
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* |
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* Copyright (c) 2008 Martin Kebert |
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* Copyright (c) 2001 Arndt Schoenewald |
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* Copyright (c) 2000-2001 Vojtech Pavlik |
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* Copyright (c) 2000 Mark Fletcher |
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*/ |
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/* |
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* Driver to use 4CH RC transmitter using Zhen Hua 5-byte protocol (Walkera Lama, |
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* EasyCopter etc.) as a joystick under Linux. |
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* |
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* RC transmitters using Zhen Hua 5-byte protocol are cheap four channels |
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* transmitters for control a RC planes or RC helicopters with possibility to |
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* connect on a serial port. |
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* Data coming from transmitter is in this order: |
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* 1. byte = synchronisation byte |
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* 2. byte = X axis |
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* 3. byte = Y axis |
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* 4. byte = RZ axis |
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* 5. byte = Z axis |
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* (and this is repeated) |
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* |
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* For questions or feedback regarding this driver module please contact: |
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* Martin Kebert <[email protected]> - but I am not a C-programmer nor kernel |
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* coder :-( |
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*/ |
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/* |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/bitrev.h> |
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#include <linux/input.h> |
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#include <linux/serio.h> |
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#define DRIVER_DESC "RC transmitter with 5-byte Zhen Hua protocol joystick driver" |
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MODULE_DESCRIPTION(DRIVER_DESC); |
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MODULE_LICENSE("GPL"); |
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/* |
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* Constants. |
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*/ |
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#define ZHENHUA_MAX_LENGTH 5 |
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/* |
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* Zhen Hua data. |
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*/ |
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struct zhenhua { |
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struct input_dev *dev; |
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int idx; |
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unsigned char data[ZHENHUA_MAX_LENGTH]; |
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char phys[32]; |
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}; |
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/* |
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* zhenhua_process_packet() decodes packets the driver receives from the |
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* RC transmitter. It updates the data accordingly. |
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*/ |
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static void zhenhua_process_packet(struct zhenhua *zhenhua) |
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{ |
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struct input_dev *dev = zhenhua->dev; |
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unsigned char *data = zhenhua->data; |
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input_report_abs(dev, ABS_Y, data[1]); |
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input_report_abs(dev, ABS_X, data[2]); |
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input_report_abs(dev, ABS_RZ, data[3]); |
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input_report_abs(dev, ABS_Z, data[4]); |
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input_sync(dev); |
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} |
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/* |
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* zhenhua_interrupt() is called by the low level driver when characters |
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* are ready for us. We then buffer them for further processing, or call the |
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* packet processing routine. |
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*/ |
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static irqreturn_t zhenhua_interrupt(struct serio *serio, unsigned char data, unsigned int flags) |
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{ |
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struct zhenhua *zhenhua = serio_get_drvdata(serio); |
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/* All Zhen Hua packets are 5 bytes. The fact that the first byte |
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* is allways 0xf7 and all others are in range 0x32 - 0xc8 (50-200) |
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* can be used to check and regain sync. */ |
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if (data == 0xef) |
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zhenhua->idx = 0; /* this byte starts a new packet */ |
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else if (zhenhua->idx == 0) |
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return IRQ_HANDLED; /* wrong MSB -- ignore this byte */ |
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if (zhenhua->idx < ZHENHUA_MAX_LENGTH) |
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zhenhua->data[zhenhua->idx++] = bitrev8(data); |
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if (zhenhua->idx == ZHENHUA_MAX_LENGTH) { |
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zhenhua_process_packet(zhenhua); |
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zhenhua->idx = 0; |
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} |
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return IRQ_HANDLED; |
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} |
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/* |
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* zhenhua_disconnect() is the opposite of zhenhua_connect() |
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*/ |
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static void zhenhua_disconnect(struct serio *serio) |
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{ |
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struct zhenhua *zhenhua = serio_get_drvdata(serio); |
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serio_close(serio); |
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serio_set_drvdata(serio, NULL); |
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input_unregister_device(zhenhua->dev); |
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kfree(zhenhua); |
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} |
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/* |
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* zhenhua_connect() is the routine that is called when someone adds a |
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* new serio device. It looks for the Twiddler, and if found, registers |
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* it as an input device. |
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*/ |
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static int zhenhua_connect(struct serio *serio, struct serio_driver *drv) |
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{ |
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struct zhenhua *zhenhua; |
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struct input_dev *input_dev; |
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int err = -ENOMEM; |
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zhenhua = kzalloc(sizeof(struct zhenhua), GFP_KERNEL); |
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input_dev = input_allocate_device(); |
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if (!zhenhua || !input_dev) |
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goto fail1; |
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zhenhua->dev = input_dev; |
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snprintf(zhenhua->phys, sizeof(zhenhua->phys), "%s/input0", serio->phys); |
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input_dev->name = "Zhen Hua 5-byte device"; |
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input_dev->phys = zhenhua->phys; |
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input_dev->id.bustype = BUS_RS232; |
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input_dev->id.vendor = SERIO_ZHENHUA; |
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input_dev->id.product = 0x0001; |
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input_dev->id.version = 0x0100; |
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input_dev->dev.parent = &serio->dev; |
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input_dev->evbit[0] = BIT(EV_ABS); |
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input_set_abs_params(input_dev, ABS_X, 50, 200, 0, 0); |
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input_set_abs_params(input_dev, ABS_Y, 50, 200, 0, 0); |
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input_set_abs_params(input_dev, ABS_Z, 50, 200, 0, 0); |
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input_set_abs_params(input_dev, ABS_RZ, 50, 200, 0, 0); |
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serio_set_drvdata(serio, zhenhua); |
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err = serio_open(serio, drv); |
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if (err) |
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goto fail2; |
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err = input_register_device(zhenhua->dev); |
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if (err) |
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goto fail3; |
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return 0; |
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fail3: serio_close(serio); |
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fail2: serio_set_drvdata(serio, NULL); |
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fail1: input_free_device(input_dev); |
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kfree(zhenhua); |
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return err; |
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} |
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/* |
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* The serio driver structure. |
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*/ |
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static const struct serio_device_id zhenhua_serio_ids[] = { |
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{ |
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.type = SERIO_RS232, |
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.proto = SERIO_ZHENHUA, |
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.id = SERIO_ANY, |
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.extra = SERIO_ANY, |
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}, |
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{ 0 } |
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}; |
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MODULE_DEVICE_TABLE(serio, zhenhua_serio_ids); |
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static struct serio_driver zhenhua_drv = { |
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.driver = { |
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.name = "zhenhua", |
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}, |
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.description = DRIVER_DESC, |
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.id_table = zhenhua_serio_ids, |
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.interrupt = zhenhua_interrupt, |
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.connect = zhenhua_connect, |
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.disconnect = zhenhua_disconnect, |
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}; |
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module_serio_driver(zhenhua_drv);
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