linux/drivers/input/tsdev.c
Dmitry Torokhov b9d2d110b1 Input: tsdev - implement proper locking
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2007-08-30 00:22:39 -04:00

698 lines
17 KiB
C

/*
* $Id: tsdev.c,v 1.15 2002/04/10 16:50:19 jsimmons Exp $
*
* Copyright (c) 2001 "Crazy" james Simmons
*
* Compaq touchscreen protocol driver. The protocol emulated by this driver
* is obsolete; for new programs use the tslib library which can read directly
* from evdev and perform dejittering, variance filtering and calibration -
* all in user space, not at kernel level. The meaning of this driver is
* to allow usage of newer input drivers with old applications that use the
* old /dev/h3600_ts and /dev/h3600_tsraw devices.
*
* 09-Apr-2004: Andrew Zabolotny <zap@homelink.ru>
* Fixed to actually work, not just output random numbers.
* Added support for both h3600_ts and h3600_tsraw protocol
* emulation.
*/
/*
* 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
*
* Should you need to contact me, the author, you can do so either by
* e-mail - mail your message to <jsimmons@infradead.org>.
*/
#define TSDEV_MINOR_BASE 128
#define TSDEV_MINORS 32
/* First 16 devices are h3600_ts compatible; second 16 are h3600_tsraw */
#define TSDEV_MINOR_MASK 15
#define TSDEV_BUFFER_SIZE 64
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/major.h>
#include <linux/random.h>
#include <linux/time.h>
#include <linux/device.h>
#ifndef CONFIG_INPUT_TSDEV_SCREEN_X
#define CONFIG_INPUT_TSDEV_SCREEN_X 240
#endif
#ifndef CONFIG_INPUT_TSDEV_SCREEN_Y
#define CONFIG_INPUT_TSDEV_SCREEN_Y 320
#endif
/* This driver emulates both protocols of the old h3600_ts and h3600_tsraw
* devices. The first one must output X/Y data in 'cooked' format, e.g.
* filtered, dejittered and calibrated. Second device just outputs raw
* data received from the hardware.
*
* This driver doesn't support filtering and dejittering; it supports only
* calibration. Filtering and dejittering must be done in the low-level
* driver, if needed, because it may gain additional benefits from knowing
* the low-level details, the nature of noise and so on.
*
* The driver precomputes a calibration matrix given the initial xres and
* yres values (quite innacurate for most touchscreens) that will result
* in a more or less expected range of output values. The driver supports
* the TS_SET_CAL ioctl, which will replace the calibration matrix with a
* new one, supposedly generated from the values taken from the raw device.
*/
MODULE_AUTHOR("James Simmons <jsimmons@transvirtual.com>");
MODULE_DESCRIPTION("Input driver to touchscreen converter");
MODULE_LICENSE("GPL");
static int xres = CONFIG_INPUT_TSDEV_SCREEN_X;
module_param(xres, uint, 0);
MODULE_PARM_DESC(xres, "Horizontal screen resolution (can be negative for X-mirror)");
static int yres = CONFIG_INPUT_TSDEV_SCREEN_Y;
module_param(yres, uint, 0);
MODULE_PARM_DESC(yres, "Vertical screen resolution (can be negative for Y-mirror)");
/* From Compaq's Touch Screen Specification version 0.2 (draft) */
struct ts_event {
short pressure;
short x;
short y;
short millisecs;
};
struct ts_calibration {
int xscale;
int xtrans;
int yscale;
int ytrans;
int xyswap;
};
struct tsdev {
int exist;
int open;
int minor;
char name[8];
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;
int x, y, pressure;
struct ts_calibration cal;
};
struct tsdev_client {
struct fasync_struct *fasync;
struct list_head node;
struct tsdev *tsdev;
struct ts_event buffer[TSDEV_BUFFER_SIZE];
int head, tail;
spinlock_t buffer_lock; /* protects access to buffer, head and tail */
int raw;
};
/* The following ioctl codes are defined ONLY for backward compatibility.
* Don't use tsdev for new developement; use the tslib library instead.
* Touchscreen calibration is a fully userspace task.
*/
/* Use 'f' as magic number */
#define IOC_H3600_TS_MAGIC 'f'
#define TS_GET_CAL _IOR(IOC_H3600_TS_MAGIC, 10, struct ts_calibration)
#define TS_SET_CAL _IOW(IOC_H3600_TS_MAGIC, 11, struct ts_calibration)
static struct tsdev *tsdev_table[TSDEV_MINORS/2];
static DEFINE_MUTEX(tsdev_table_mutex);
static int tsdev_fasync(int fd, struct file *file, int on)
{
struct tsdev_client *client = file->private_data;
int retval;
retval = fasync_helper(fd, file, on, &client->fasync);
return retval < 0 ? retval : 0;
}
static void tsdev_free(struct device *dev)
{
struct tsdev *tsdev = container_of(dev, struct tsdev, dev);
kfree(tsdev);
}
static void tsdev_attach_client(struct tsdev *tsdev, struct tsdev_client *client)
{
spin_lock(&tsdev->client_lock);
list_add_tail_rcu(&client->node, &tsdev->client_list);
spin_unlock(&tsdev->client_lock);
synchronize_sched();
}
static void tsdev_detach_client(struct tsdev *tsdev, struct tsdev_client *client)
{
spin_lock(&tsdev->client_lock);
list_del_rcu(&client->node);
spin_unlock(&tsdev->client_lock);
synchronize_sched();
}
static int tsdev_open_device(struct tsdev *tsdev)
{
int retval;
retval = mutex_lock_interruptible(&tsdev->mutex);
if (retval)
return retval;
if (!tsdev->exist)
retval = -ENODEV;
else if (!tsdev->open++)
retval = input_open_device(&tsdev->handle);
mutex_unlock(&tsdev->mutex);
return retval;
}
static void tsdev_close_device(struct tsdev *tsdev)
{
mutex_lock(&tsdev->mutex);
if (tsdev->exist && !--tsdev->open)
input_close_device(&tsdev->handle);
mutex_unlock(&tsdev->mutex);
}
/*
* Wake up users waiting for IO so they can disconnect from
* dead device.
*/
static void tsdev_hangup(struct tsdev *tsdev)
{
struct tsdev_client *client;
spin_lock(&tsdev->client_lock);
list_for_each_entry(client, &tsdev->client_list, node)
kill_fasync(&client->fasync, SIGIO, POLL_HUP);
spin_unlock(&tsdev->client_lock);
wake_up_interruptible(&tsdev->wait);
}
static int tsdev_release(struct inode *inode, struct file *file)
{
struct tsdev_client *client = file->private_data;
struct tsdev *tsdev = client->tsdev;
tsdev_fasync(-1, file, 0);
tsdev_detach_client(tsdev, client);
kfree(client);
tsdev_close_device(tsdev);
put_device(&tsdev->dev);
return 0;
}
static int tsdev_open(struct inode *inode, struct file *file)
{
int i = iminor(inode) - TSDEV_MINOR_BASE;
struct tsdev_client *client;
struct tsdev *tsdev;
int error;
printk(KERN_WARNING "tsdev (compaq touchscreen emulation) is scheduled "
"for removal.\nSee Documentation/feature-removal-schedule.txt "
"for details.\n");
if (i >= TSDEV_MINORS)
return -ENODEV;
error = mutex_lock_interruptible(&tsdev_table_mutex);
if (error)
return error;
tsdev = tsdev_table[i & TSDEV_MINOR_MASK];
if (tsdev)
get_device(&tsdev->dev);
mutex_unlock(&tsdev_table_mutex);
if (!tsdev)
return -ENODEV;
client = kzalloc(sizeof(struct tsdev_client), GFP_KERNEL);
if (!client) {
error = -ENOMEM;
goto err_put_tsdev;
}
spin_lock_init(&client->buffer_lock);
client->tsdev = tsdev;
client->raw = i >= TSDEV_MINORS / 2;
tsdev_attach_client(tsdev, client);
error = tsdev_open_device(tsdev);
if (error)
goto err_free_client;
file->private_data = client;
return 0;
err_free_client:
tsdev_detach_client(tsdev, client);
kfree(client);
err_put_tsdev:
put_device(&tsdev->dev);
return error;
}
static int tsdev_fetch_next_event(struct tsdev_client *client,
struct ts_event *event)
{
int have_event;
spin_lock_irq(&client->buffer_lock);
have_event = client->head != client->tail;
if (have_event) {
*event = client->buffer[client->tail++];
client->tail &= TSDEV_BUFFER_SIZE - 1;
}
spin_unlock_irq(&client->buffer_lock);
return have_event;
}
static ssize_t tsdev_read(struct file *file, char __user *buffer, size_t count,
loff_t *ppos)
{
struct tsdev_client *client = file->private_data;
struct tsdev *tsdev = client->tsdev;
struct ts_event event;
int retval;
if (client->head == client->tail && tsdev->exist &&
(file->f_flags & O_NONBLOCK))
return -EAGAIN;
retval = wait_event_interruptible(tsdev->wait,
client->head != client->tail || !tsdev->exist);
if (retval)
return retval;
if (!tsdev->exist)
return -ENODEV;
while (retval + sizeof(struct ts_event) <= count &&
tsdev_fetch_next_event(client, &event)) {
if (copy_to_user(buffer + retval, &event,
sizeof(struct ts_event)))
return -EFAULT;
retval += sizeof(struct ts_event);
}
return retval;
}
/* No kernel lock - fine */
static unsigned int tsdev_poll(struct file *file, poll_table *wait)
{
struct tsdev_client *client = file->private_data;
struct tsdev *tsdev = client->tsdev;
poll_wait(file, &tsdev->wait, wait);
return ((client->head == client->tail) ? 0 : (POLLIN | POLLRDNORM)) |
(tsdev->exist ? 0 : (POLLHUP | POLLERR));
}
static long tsdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct tsdev_client *client = file->private_data;
struct tsdev *tsdev = client->tsdev;
int retval = 0;
retval = mutex_lock_interruptible(&tsdev->mutex);
if (retval)
return retval;
if (!tsdev->exist) {
retval = -ENODEV;
goto out;
}
switch (cmd) {
case TS_GET_CAL:
if (copy_to_user((void __user *)arg, &tsdev->cal,
sizeof (struct ts_calibration)))
retval = -EFAULT;
break;
case TS_SET_CAL:
if (copy_from_user(&tsdev->cal, (void __user *)arg,
sizeof(struct ts_calibration)))
retval = -EFAULT;
break;
default:
retval = -EINVAL;
break;
}
out:
mutex_unlock(&tsdev->mutex);
return retval;
}
static const struct file_operations tsdev_fops = {
.owner = THIS_MODULE,
.open = tsdev_open,
.release = tsdev_release,
.read = tsdev_read,
.poll = tsdev_poll,
.fasync = tsdev_fasync,
.unlocked_ioctl = tsdev_ioctl,
};
static void tsdev_pass_event(struct tsdev *tsdev, struct tsdev_client *client,
int x, int y, int pressure, int millisecs)
{
struct ts_event *event;
int tmp;
/* Interrupts are already disabled, just acquire the lock */
spin_lock(&client->buffer_lock);
event = &client->buffer[client->head++];
client->head &= TSDEV_BUFFER_SIZE - 1;
/* Calibration */
if (!client->raw) {
x = ((x * tsdev->cal.xscale) >> 8) + tsdev->cal.xtrans;
y = ((y * tsdev->cal.yscale) >> 8) + tsdev->cal.ytrans;
if (tsdev->cal.xyswap) {
tmp = x; x = y; y = tmp;
}
}
event->millisecs = millisecs;
event->x = x;
event->y = y;
event->pressure = pressure;
spin_unlock(&client->buffer_lock);
kill_fasync(&client->fasync, SIGIO, POLL_IN);
}
static void tsdev_distribute_event(struct tsdev *tsdev)
{
struct tsdev_client *client;
struct timeval time;
int millisecs;
do_gettimeofday(&time);
millisecs = time.tv_usec / 1000;
list_for_each_entry_rcu(client, &tsdev->client_list, node)
tsdev_pass_event(tsdev, client,
tsdev->x, tsdev->y,
tsdev->pressure, millisecs);
}
static void tsdev_event(struct input_handle *handle, unsigned int type,
unsigned int code, int value)
{
struct tsdev *tsdev = handle->private;
struct input_dev *dev = handle->dev;
int wake_up_readers = 0;
switch (type) {
case EV_ABS:
switch (code) {
case ABS_X:
tsdev->x = value;
break;
case ABS_Y:
tsdev->y = value;
break;
case ABS_PRESSURE:
if (value > dev->absmax[ABS_PRESSURE])
value = dev->absmax[ABS_PRESSURE];
value -= dev->absmin[ABS_PRESSURE];
if (value < 0)
value = 0;
tsdev->pressure = value;
break;
}
break;
case EV_REL:
switch (code) {
case REL_X:
tsdev->x += value;
if (tsdev->x < 0)
tsdev->x = 0;
else if (tsdev->x > xres)
tsdev->x = xres;
break;
case REL_Y:
tsdev->y += value;
if (tsdev->y < 0)
tsdev->y = 0;
else if (tsdev->y > yres)
tsdev->y = yres;
break;
}
break;
case EV_KEY:
if (code == BTN_TOUCH || code == BTN_MOUSE) {
switch (value) {
case 0:
tsdev->pressure = 0;
break;
case 1:
if (!tsdev->pressure)
tsdev->pressure = 1;
break;
}
}
break;
case EV_SYN:
if (code == SYN_REPORT) {
tsdev_distribute_event(tsdev);
wake_up_readers = 1;
}
break;
}
if (wake_up_readers)
wake_up_interruptible(&tsdev->wait);
}
static int tsdev_install_chrdev(struct tsdev *tsdev)
{
tsdev_table[tsdev->minor] = tsdev;
return 0;
}
static void tsdev_remove_chrdev(struct tsdev *tsdev)
{
mutex_lock(&tsdev_table_mutex);
tsdev_table[tsdev->minor] = NULL;
mutex_unlock(&tsdev_table_mutex);
}
/*
* Mark device non-existant. This disables writes, ioctls and
* prevents new users from opening the device. Already posted
* blocking reads will stay, however new ones will fail.
*/
static void tsdev_mark_dead(struct tsdev *tsdev)
{
mutex_lock(&tsdev->mutex);
tsdev->exist = 0;
mutex_unlock(&tsdev->mutex);
}
static void tsdev_cleanup(struct tsdev *tsdev)
{
struct input_handle *handle = &tsdev->handle;
tsdev_mark_dead(tsdev);
tsdev_hangup(tsdev);
tsdev_remove_chrdev(tsdev);
/* tsdev is marked dead so noone else accesses tsdev->open */
if (tsdev->open)
input_close_device(handle);
}
static int tsdev_connect(struct input_handler *handler, struct input_dev *dev,
const struct input_device_id *id)
{
struct tsdev *tsdev;
int delta;
int minor;
int error;
for (minor = 0; minor < TSDEV_MINORS / 2; minor++)
if (!tsdev_table[minor])
break;
if (minor == TSDEV_MINORS) {
printk(KERN_ERR "tsdev: no more free tsdev devices\n");
return -ENFILE;
}
tsdev = kzalloc(sizeof(struct tsdev), GFP_KERNEL);
if (!tsdev)
return -ENOMEM;
INIT_LIST_HEAD(&tsdev->client_list);
spin_lock_init(&tsdev->client_lock);
mutex_init(&tsdev->mutex);
init_waitqueue_head(&tsdev->wait);
snprintf(tsdev->name, sizeof(tsdev->name), "ts%d", minor);
tsdev->exist = 1;
tsdev->minor = minor;
tsdev->handle.dev = dev;
tsdev->handle.name = tsdev->name;
tsdev->handle.handler = handler;
tsdev->handle.private = tsdev;
/* Precompute the rough calibration matrix */
delta = dev->absmax [ABS_X] - dev->absmin [ABS_X] + 1;
if (delta == 0)
delta = 1;
tsdev->cal.xscale = (xres << 8) / delta;
tsdev->cal.xtrans = - ((dev->absmin [ABS_X] * tsdev->cal.xscale) >> 8);
delta = dev->absmax [ABS_Y] - dev->absmin [ABS_Y] + 1;
if (delta == 0)
delta = 1;
tsdev->cal.yscale = (yres << 8) / delta;
tsdev->cal.ytrans = - ((dev->absmin [ABS_Y] * tsdev->cal.yscale) >> 8);
strlcpy(tsdev->dev.bus_id, tsdev->name, sizeof(tsdev->dev.bus_id));
tsdev->dev.devt = MKDEV(INPUT_MAJOR, TSDEV_MINOR_BASE + minor);
tsdev->dev.class = &input_class;
tsdev->dev.parent = &dev->dev;
tsdev->dev.release = tsdev_free;
device_initialize(&tsdev->dev);
error = input_register_handle(&tsdev->handle);
if (error)
goto err_free_tsdev;
error = tsdev_install_chrdev(tsdev);
if (error)
goto err_unregister_handle;
error = device_add(&tsdev->dev);
if (error)
goto err_cleanup_tsdev;
return 0;
err_cleanup_tsdev:
tsdev_cleanup(tsdev);
err_unregister_handle:
input_unregister_handle(&tsdev->handle);
err_free_tsdev:
put_device(&tsdev->dev);
return error;
}
static void tsdev_disconnect(struct input_handle *handle)
{
struct tsdev *tsdev = handle->private;
device_del(&tsdev->dev);
tsdev_cleanup(tsdev);
input_unregister_handle(handle);
put_device(&tsdev->dev);
}
static const struct input_device_id tsdev_ids[] = {
{
.flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT | INPUT_DEVICE_ID_MATCH_RELBIT,
.evbit = { BIT(EV_KEY) | BIT(EV_REL) },
.keybit = { [LONG(BTN_LEFT)] = BIT(BTN_LEFT) },
.relbit = { BIT(REL_X) | BIT(REL_Y) },
}, /* A mouse like device, at least one button, two relative axes */
{
.flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT | INPUT_DEVICE_ID_MATCH_ABSBIT,
.evbit = { BIT(EV_KEY) | BIT(EV_ABS) },
.keybit = { [LONG(BTN_TOUCH)] = BIT(BTN_TOUCH) },
.absbit = { BIT(ABS_X) | BIT(ABS_Y) },
}, /* A tablet like device, at least touch detection, two absolute axes */
{
.flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_ABSBIT,
.evbit = { BIT(EV_ABS) },
.absbit = { BIT(ABS_X) | BIT(ABS_Y) | BIT(ABS_PRESSURE) },
}, /* A tablet like device with several gradations of pressure */
{} /* Terminating entry */
};
MODULE_DEVICE_TABLE(input, tsdev_ids);
static struct input_handler tsdev_handler = {
.event = tsdev_event,
.connect = tsdev_connect,
.disconnect = tsdev_disconnect,
.fops = &tsdev_fops,
.minor = TSDEV_MINOR_BASE,
.name = "tsdev",
.id_table = tsdev_ids,
};
static int __init tsdev_init(void)
{
return input_register_handler(&tsdev_handler);
}
static void __exit tsdev_exit(void)
{
input_unregister_handler(&tsdev_handler);
}
module_init(tsdev_init);
module_exit(tsdev_exit);