path: root/drivers/input/joydev.c

/*
 * Joystick device driver for the input driver suite.
 *
 * Copyright (c) 1999-2002 Vojtech Pavlik
 * Copyright (c) 1999 Colin Van Dyke
 *
 * 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.
 */

#include <asm/io.h>
#include <asm/system.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/joystick.h>
#include <linux/input.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/device.h>

MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION("Joystick device interfaces");
MODULE_SUPPORTED_DEVICE("input/js");
MODULE_LICENSE("GPL");

#define JOYDEV_MINOR_BASE	0
#define JOYDEV_MINORS		16
#define JOYDEV_BUFFER_SIZE	64

struct joydev {
	int exist;
	int open;
	int minor;
	char name[16];
	struct input_handle handle;
	wait_queue_head_t wait;
	struct list_head client_list;
	spinlock_t client_lock; /* protects client_list */
	struct mutex mutex;
	struct device dev;

	struct js_corr corr[ABS_MAX + 1];
	struct JS_DATA_SAVE_TYPE glue;
	int nabs;
	int nkey;
	__u16 keymap[KEY_MAX - BTN_MISC + 1];
	__u16 keypam[KEY_MAX - BTN_MISC + 1];
	__u8 absmap[ABS_MAX + 1];
	__u8 abspam[ABS_MAX + 1];
	__s16 abs[ABS_MAX + 1];
};

struct joydev_client {
	struct js_event buffer[JOYDEV_BUFFER_SIZE];
	int head;
	int tail;
	int startup;
	spinlock_t buffer_lock; /* protects access to buffer, head and tail */
	struct fasync_struct *fasync;
	struct joydev *joydev;
	struct list_head node;
};

static struct joydev *joydev_table[JOYDEV_MINORS];
static DEFINE_MUTEX(joydev_table_mutex);

static int joydev_correct(int value, struct js_corr *corr)
{
	switch (corr->type) {

	case JS_CORR_NONE:
		break;

	case JS_CORR_BROKEN:
		value = value > corr->coef[0] ? (value < corr->coef[1] ? 0 :
			((corr->coef[3] * (value - corr->coef[1])) >> 14)) :
			((corr->coef[2] * (value - corr->coef[0])) >> 14);
		break;

	default:
		return 0;
	}

	return value < -32767 ? -32767 : (value > 32767 ? 32767 : value);
}

static void joydev_pass_event(struct joydev_client *client,
			      struct js_event *event)
{
	struct joydev *joydev = client->joydev;

	/*
	 * IRQs already disabled, just acquire the lock
	 */
	spin_lock(&client->buffer_lock);

	client->buffer[client->head] = *event;

	if (client->startup == joydev->nabs + joydev->nkey) {
		client->head++;
		client->head &= JOYDEV_BUFFER_SIZE - 1;
		if (client->tail == client->head)
			client->startup = 0;
	}

	spin_unlock(&client->buffer_lock);

	kill_fasync(&client->fasync, SIGIO, POLL_IN);
}

static void joydev_event(struct input_handle *handle,
			 unsigned int type, unsigned int code, int value)
{
	struct joydev *joydev = handle->private;
	struct joydev_client *client;
	struct js_event event;

	switch (type) {

	case EV_KEY:
		if (code < BTN_MISC || value == 2)
			return;
		event.type = JS_EVENT_BUTTON;
		event.number = joydev->keymap[code - BTN_MISC];
		event.value = value;
		break;

	case EV_ABS:
		event.type = JS_EVENT_AXIS;
		event.number = joydev->absmap[code];
		event.value = joydev_correct(value,
					&joydev->corr[event.number]);
		if (event.value == joydev->abs[event.number])
			return;
		joydev->abs[event.number] = event.value;
		break;

	default:
		return;
	}

	event.time = jiffies_to_msecs(jiffies);

	rcu_read_lock();
	list_for_each_entry_rcu(client, &joydev->client_list, node)
		joydev_pass_event(client, &event);
	rcu_read_unlock();

	wake_up_interruptible(&joydev->wait);
}

static int joydev_fasync(int fd, struct file *file, int on)
{
	int retval;
	struct joydev_client *client = file->private_data;

	retval = fasync_helper(fd