pc110pad.c

这是一个SIGMA方案的PMP播放器的UCLINUX程序,可播放DVD,VCD,CD MP3...有很好的参考价值.

 */
static int read_bytes[3];
static int read_byte_count;

/**
 *	sample_raw:
 *	@d: sample buffer
 *
 *	Retrieve a triple of sample data. 
 */


static void sample_raw(int d[3])
{
	d[0]=raw_data[0];
	d[1]=raw_data[1];
	d[2]=raw_data[2];
}

/**
 *	sample_rare:
 *	@d: sample buffer
 *
 *	Retrieve a triple of sample data and sanitize it. We do the needed
 *	scaling and masking to get the current status.
 */


static void sample_rare(int d[3])
{
	int thisd, thisdd, thisx, thisy;

	read_raw_pad(&thisd, &thisdd, &thisx, &thisy);

	d[0]=(thisd?0x80:0)
	   | (thisx/256)<<4
	   | (thisdd?0x08:0)
	   | (thisy/256)
	;
	d[1]=thisx%256;
	d[2]=thisy%256;
}

/**
 *	sample_debug:
 *	@d: sample buffer
 *
 *	Retrieve a triple of sample data and mix it up with the state 
 *	information in the gesture parser. Not useful for normal users but
 *	handy when debugging
 */

static void sample_debug(int d[3])
{
	int thisd, thisdd, thisx, thisy;
	int b;
	unsigned long flags;
	
	save_flags(flags);
	cli();
	read_raw_pad(&thisd, &thisdd, &thisx, &thisy);
	d[0]=(thisd?0x80:0) | (thisdd?0x40:0) | bounce;
	d[1]=(recent_transition?0x80:0)+transition_count;
	read_button(&b);
	d[2]=(synthesize_tap<<4) | (b?0x01:0);
	restore_flags(flags);
}

/**
 *	sample_ps2:
 *	@d: sample buffer
 *
 *	Retrieve a triple of sample data and turn the debounced tap and
 *	stroke information into what appears to be a PS/2 mouse. This means
 *	the PC110 pad needs no funny application side support.
 */


static void sample_ps2(int d[3])
{
	static int lastx, lasty, lastd;

	int thisd, thisdd, thisx, thisy;
	int dx, dy, b;

	/*
	 * Obtain the current mouse parameters and limit as appropriate for
	 * the return data format.  Interrupts are only disabled while 
	 * obtaining the parameters, NOT during the puts_fs_byte() calls,
	 * so paging in put_user() does not affect mouse tracking.
	 */
	read_raw_pad(&thisd, &thisdd, &thisx, &thisy);
	read_button(&b);

	/* Now compare with previous readings.  Note that we use the
	 * raw down flag rather than the debounced one.
	 */
	if( (thisd && !lastd) /* new stroke */
	 || (bounce!=NO_BOUNCE) )
	{
		dx=0;
		dy=0;
	}
	else
	{
		dx =  (thisx-lastx);
		dy = -(thisy-lasty);
	}
	lastx=thisx;
	lasty=thisy;
	lastd=thisd;

/*
	d[0]= ((dy<0)?0x20:0)
	    | ((dx<0)?0x10:0)
	    | 0x08
	    | (b? 0x01:0x00)
	;
*/
	d[0]= ((dy<0)?0x20:0)
	    | ((dx<0)?0x10:0)
	    | (b? 0x00:0x08)
	;
	d[1]=dx;
	d[2]=dy;
}


/**
 *	fasync_pad:
 *	@fd:	file number for the file 
 *	@filp:	file handle
 *	@on:	1 to add, 0 to remove a notifier
 *
 *	Update the queue of asynchronous event notifiers. We can use the
 *	same helper the mice do and that does almost everything we need.
 */
 
static int fasync_pad(int fd, struct file *filp, int on)
{
	int retval;

	retval = fasync_helper(fd, filp, on, &asyncptr);
	if (retval < 0)
		return retval;
	return 0;
}


/**
 *	close_pad:
 *	@inode: inode of pad
 *	@file: file handle to pad
 *
 *	Close access to the pad. We turn the pad power off if this is the
 *	last user of the pad. I've not actually measured the power draw but
 *	the DOS driver is careful to do this so we follow suit.
 */
 
static int close_pad(struct inode * inode, struct file * file)
{
	lock_kernel();
	fasync_pad(-1, file, 0);
	if (!--active)
		outb(0x30, current_params.io+2);  /* switch off digitiser */
	unlock_kernel();
	return 0;
}


/**
 *	open_pad:
 *	@inode: inode of pad
 *	@file: file handle to pad
 *
 *	Open access to the pad. We turn the pad off first (we turned it off
 *	on close but if this is the first open after a crash the state is
 *	indeterminate). The device has a small fifo so we empty that before
 *	we kick it back into action.
 */
 
static int open_pad(struct inode * inode, struct file * file)
{
	unsigned long flags;
	
	if (active++)
		return 0;

	save_flags(flags);
	cli();
	outb(0x30, current_params.io+2);	/* switch off digitiser */
	pad_irq(0,0,0);		/* read to flush any pending bytes */
	pad_irq(0,0,0);		/* read to flush any pending bytes */
	pad_irq(0,0,0);		/* read to flush any pending bytes */
	outb(0x38, current_params.io+2);	/* switch on digitiser */
	current_params = default_params;
	raw_data_count=0;		/* re-sync input byte counter */
	read_byte_count=0;		/* re-sync output byte counter */
	button_pending=0;
	recent_transition=0;
	transition_count=0;
	synthesize_tap=0;
	del_timer(&bounce_timer);
	del_timer(&tap_timer);
	restore_flags(flags);

	return 0;
}


/**
 *	write_pad:
 *	@file: File handle to the pad
 *	@buffer: Unused
 *	@count: Unused
 *	@ppos: Unused
 *
 *	Writes are disallowed. A true PS/2 mouse lets you write stuff. Everyone
 *	seems happy with this and not faking the write modes.
 */

static ssize_t write_pad(struct file * file, const char * buffer, size_t count, loff_t *ppos)
{
	return -EINVAL;
}


/*
 *	new_sample:
 *	@d: sample buffer
 *
 *	Fetch a new sample according the current mouse mode the pad is 
 *	using.
 */
 
void new_sample(int d[3])
{
	switch(current_params.mode)
	{
		case PC110PAD_RAW:	sample_raw(d);		break;
		case PC110PAD_RARE:	sample_rare(d);		break;
		case PC110PAD_DEBUG:	sample_debug(d);	break;
		case PC110PAD_PS2:	sample_ps2(d);		break;
	}
}


/**
 * read_pad:
 * @file: File handle to pad
 * @buffer: Target for the mouse data
 * @count: Buffer length
 * @ppos: Offset (unused)
 *
 * Read data from the pad. We use the reader_lock to avoid mess when there are
 * two readers. This shouldnt be happening anyway but we play safe.
 */
 
static ssize_t read_pad(struct file * file, char * buffer, size_t count, loff_t *ppos)
{
	int r;

	down(&reader_lock);
	for(r=0; r<count; r++)
	{
		if(!read_byte_count)
			new_sample(read_bytes);
		if(put_user(read_bytes[read_byte_count], buffer+r))
		{
			r = -EFAULT;
			break;
		}
		read_byte_count = (read_byte_count+1)%3;
	}
	up(&reader_lock);
	return r;
}


/**
 * pad_poll:
 * @file: File of the pad device
 * @wait: Poll table
 *
 * The pad is ready to read if there is a button or any position change
 * pending in the queue. The reading and interrupt routines maintain the
 * required state for us and do needed wakeups.
 */

static unsigned int pad_poll(struct file *file, poll_table * wait)
{
	poll_wait(file, &queue, wait);
    	if(button_pending || xy_pending)
		return POLLIN | POLLRDNORM;
	return 0;
}


/**
 *	pad_ioctl;
 *	@inode: Inode of the pad
 *	@file: File handle to the pad
 *	@cmd: Ioctl command
 *	@arg: Argument pointer
 *
 *	The PC110 pad supports two ioctls both of which use the pc110pad_params
 *	structure. GETP queries the current pad status. SETP changes the pad
 *	configuration. Changing configuration during normal mouse operations
 *	may give momentarily odd results as things like tap gesture state
 *	may be lost.
 */
 
static int pad_ioctl(struct inode *inode, struct file * file,
	unsigned int cmd, unsigned long arg)
{
	struct pc110pad_params new;

	if (!inode)
		return -EINVAL;
		
	switch (cmd) {
	case PC110PADIOCGETP:
		new = current_params;
		if(copy_to_user((void *)arg, &new, sizeof(new)))
			return -EFAULT;
		return 0;

	case PC110PADIOCSETP:
		if(copy_from_user(&new, (void *)arg, sizeof(new)))
			return -EFAULT;

		if( (new.mode<PC110PAD_RAW)
		 || (new.mode>PC110PAD_PS2)
		 || (new.bounce_interval<0)
		 || (new.tap_interval<0)
		)
			return -EINVAL;

		current_params.mode	= new.mode;
		current_params.bounce_interval	= new.bounce_interval;
		current_params.tap_interval	= new.tap_interval;
		return 0;
	}
	return -ENOTTY;
}


static struct file_operations pad_fops = {
	owner:		THIS_MODULE,
	read:		read_pad,
	write:		write_pad,
	poll:		pad_poll,
	ioctl:		pad_ioctl,
	open:		open_pad,
	release:	close_pad,
	fasync:		fasync_pad,
};


static struct miscdevice pc110_pad = {
	minor:		PC110PAD_MINOR,
	name:		"pc110 pad",
	fops:		&pad_fops,
};


/**
 *	pc110pad_init_driver:
 *
 *	We configure the pad with the default parameters (that is PS/2 
 *	emulation mode. We then claim the needed I/O and interrupt resources.
 *	Finally as a matter of paranoia we turn the pad off until we are
 *	asked to open it by an application.
 */

static char banner[] __initdata = KERN_INFO "PC110 digitizer pad at 0x%X, irq %d.\n";

static int __init pc110pad_init_driver(void)
{
	init_MUTEX(&reader_lock);
	current_params = default_params;

	if (request_irq(current_params.irq, pad_irq, 0, "pc110pad", 0)) {
		printk(KERN_ERR "pc110pad: Unable to get IRQ.\n");
		return -EBUSY;
	}
	if (!request_region(current_params.io, 4, "pc110pad"))	{
		printk(KERN_ERR "pc110pad: I/O area in use.\n");
		free_irq(current_params.irq,0);
		return -EBUSY;
	}
	init_waitqueue_head(&queue);
	printk(banner, current_params.io, current_params.irq);
	misc_register(&pc110_pad);
	outb(0x30, current_params.io+2);	/* switch off digitiser */
	return 0;
}

/*
 *	pc110pad_exit_driver:
 *
 *	Free the resources we acquired when the module was loaded. We also
 *	turn the pad off to be sure we don't leave it using power.
 */

static void __exit pc110pad_exit_driver(void)
{
	outb(0x30, current_params.io+2);	/* switch off digitiser */
	if (current_params.irq)
		free_irq(current_params.irq, 0);
	current_params.irq = 0;
	release_region(current_params.io, 4);
	misc_deregister(&pc110_pad);
}

module_init(pc110pad_init_driver);
module_exit(pc110pad_exit_driver);

MODULE_AUTHOR("Alan Cox, Robin O'Leary");
MODULE_DESCRIPTION("Driver for the touchpad on the IBM PC110 palmtop");
MODULE_LICENSE("GPL");

EXPORT_NO_SYMBOLS;