cregit-Linux how code gets into the kernel

Release 4.14 drivers/input/joystick/zhenhua.c

/*
 *  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 :-(
 */

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#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); }

Contributors

PersonTokensPropCommitsCommitProp
Martin Kebert82100.00%1100.00%
Total82100.00%1100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Martin Kebert10299.03%150.00%
Yalin Wang10.97%150.00%
Total103100.00%2100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Martin Kebert45100.00%1100.00%
Total45100.00%1100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Martin Kebert289100.00%1100.00%
Total289100.00%1100.00%

/* * 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);

Overall Contributors

PersonTokensPropCommitsCommitProp
Martin Kebert67398.97%125.00%
Yalin Wang40.59%125.00%
Axel Lin20.29%125.00%
Arvind Yadav10.15%125.00%
Total680100.00%4100.00%
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