/*
   * Drivers for the Total Impact PPC based computer "BRIQ"
   * by Dr. Karsten Jeppesen
   *
   */
  
  #include <linux/module.h>
  
  #include <linux/types.h>
  #include <linux/errno.h>

  #include <linux/tty.h>
  #include <linux/timer.h>

  #include <linux/kernel.h>
  #include <linux/wait.h>
  #include <linux/string.h>

  #include <linux/ioport.h>
  #include <linux/delay.h>
  #include <linux/miscdevice.h>
  #include <linux/fs.h>
  #include <linux/mm.h>
  #include <linux/init.h>
  
  #include <asm/uaccess.h>
  #include <asm/io.h>
  #include <asm/prom.h>
  
  #define		BRIQ_PANEL_MINOR	156
  #define		BRIQ_PANEL_VFD_IOPORT	0x0390
  #define		BRIQ_PANEL_LED_IOPORT	0x0398
  #define		BRIQ_PANEL_VER		"1.1 (04/20/2002)"
  #define		BRIQ_PANEL_MSG0		"Loading Linux"
  
  static int		vfd_is_open;
  static unsigned char	vfd[40];
  static int		vfd_cursor;
  static unsigned char	ledpb, led;
  
  static void update_vfd(void)
  {
  	int	i;
  
  	/* cursor home */
  	outb(0x02, BRIQ_PANEL_VFD_IOPORT);
  	for (i=0; i<20; i++)
  		outb(vfd[i], BRIQ_PANEL_VFD_IOPORT + 1);
  
  	/* cursor to next line */
  	outb(0xc0, BRIQ_PANEL_VFD_IOPORT);
  	for (i=20; i<40; i++)
  		outb(vfd[i], BRIQ_PANEL_VFD_IOPORT + 1);
  
  }
  
  static void set_led(char state)
  {
  	if (state == 'R')
  		led = 0x01;
  	else if (state == 'G')
  		led = 0x02;
  	else if (state == 'Y')
  		led = 0x03;
  	else if (state == 'X')
  		led = 0x00;
  	outb(led, BRIQ_PANEL_LED_IOPORT);
  }
  
  static int briq_panel_open(struct inode *ino, struct file *filep)
  {

  	tty_lock();

  	/* enforce single access, vfd_is_open is protected by BKL */
  	if (vfd_is_open) {

  		tty_unlock();

  		return -EBUSY;

  	}

  	vfd_is_open = 1;

  	tty_unlock();

  	return 0;
  }
  
  static int briq_panel_release(struct inode *ino, struct file *filep)
  {
  	if (!vfd_is_open)
  		return -ENODEV;
  
  	vfd_is_open = 0;
  
  	return 0;
  }

  static ssize_t briq_panel_read(struct file *file, char __user *buf, size_t count,

  			 loff_t *ppos)
  {
  	unsigned short c;
  	unsigned char cp;

  	if (!vfd_is_open)
  		return -ENODEV;
  
  	c = (inb(BRIQ_PANEL_LED_IOPORT) & 0x000c) | (ledpb & 0x0003);
  	set_led(' ');
  	/* upper button released */
  	if ((!(ledpb & 0x0004)) && (c & 0x0004)) {
  		cp = ' ';
  		ledpb = c;
  		if (copy_to_user(buf, &cp, 1))
  			return -EFAULT;
  		return 1;
  	}
  	/* lower button released */
  	else if ((!(ledpb & 0x0008)) && (c & 0x0008)) {
  		cp = '\r';
  		ledpb = c;
  		if (copy_to_user(buf, &cp, 1))
  			return -EFAULT;
  		return 1;
  	} else {
  		ledpb = c;
  		return 0;
  	}
  }
  
  static void scroll_vfd( void )
  {
  	int	i;
  
  	for (i=0; i<20; i++) {
  		vfd[i] = vfd[i+20];
  		vfd[i+20] = ' ';
  	}
  	vfd_cursor = 20;
  }

  static ssize_t briq_panel_write(struct file *file, const char __user *buf, size_t len,

  			  loff_t *ppos)
  {
  	size_t indx = len;
  	int i, esc = 0;

  	if (!vfd_is_open)
  		return -EBUSY;
  
  	for (;;) {

  		char c;

  		if (!indx)
  			break;

  		if (get_user(c, buf))
  			return -EFAULT;

  		if (esc) {

  			set_led(c);

  			esc = 0;

  		} else if (c == 27) {

  			esc = 1;

  		} else if (c == 12) {

  			/* do a form feed */
  			for (i=0; i<40; i++)
  				vfd[i] = ' ';
  			vfd_cursor = 0;

  		} else if (c == 10) {

  			if (vfd_cursor < 20)
  				vfd_cursor = 20;
  			else if (vfd_cursor < 40)
  				vfd_cursor = 40;
  			else if (vfd_cursor < 60)
  				vfd_cursor = 60;
  			if (vfd_cursor > 59)
  				scroll_vfd();
  		} else {
  			/* just a character */
  			if (vfd_cursor > 39)
  				scroll_vfd();

  			vfd[vfd_cursor++] = c;

  		}
  		indx--;
  		buf++;
  	}
  	update_vfd();
  
  	return len;
  }

  static const struct file_operations briq_panel_fops = {

  	.owner		= THIS_MODULE,
  	.read		= briq_panel_read,
  	.write		= briq_panel_write,
  	.open		= briq_panel_open,
  	.release	= briq_panel_release,

  	.llseek		= noop_llseek,

  };
  
  static struct miscdevice briq_panel_miscdev = {
  	BRIQ_PANEL_MINOR,
  	"briq_panel",
  	&briq_panel_fops
  };
  
  static int __init briq_panel_init(void)
  {

  	struct device_node *root = of_find_node_by_path("/");

  	const char *machine;

  	int i;

  	machine = of_get_property(root, "model", NULL);

  	if (!machine || strncmp(machine, "TotalImpact,BRIQ-1", 18) != 0) {
  		of_node_put(root);

  		return -ENODEV;

  	}
  	of_node_put(root);

  
  	printk(KERN_INFO
  		"briq_panel: v%s Dr. Karsten Jeppesen (kj@totalimpact.com)
  ",
  		BRIQ_PANEL_VER);
  
  	if (!request_region(BRIQ_PANEL_VFD_IOPORT, 4, "BRIQ Front Panel"))
  		return -EBUSY;
  
  	if (!request_region(BRIQ_PANEL_LED_IOPORT, 2, "BRIQ Front Panel")) {
  		release_region(BRIQ_PANEL_VFD_IOPORT, 4);
  		return -EBUSY;
  	}
  	ledpb = inb(BRIQ_PANEL_LED_IOPORT) & 0x000c;
  
  	if (misc_register(&briq_panel_miscdev) < 0) {
  		release_region(BRIQ_PANEL_VFD_IOPORT, 4);
  		release_region(BRIQ_PANEL_LED_IOPORT, 2);
  		return -EBUSY;
  	}
  
  	outb(0x38, BRIQ_PANEL_VFD_IOPORT);	/* Function set */
  	outb(0x01, BRIQ_PANEL_VFD_IOPORT);	/* Clear display */
  	outb(0x0c, BRIQ_PANEL_VFD_IOPORT);	/* Display on */
  	outb(0x06, BRIQ_PANEL_VFD_IOPORT);	/* Entry normal */
  	for (i=0; i<40; i++)
  		vfd[i]=' ';
  #ifndef MODULE
  	vfd[0] = 'L';
  	vfd[1] = 'o';
  	vfd[2] = 'a';
  	vfd[3] = 'd';
  	vfd[4] = 'i';
  	vfd[5] = 'n';
  	vfd[6] = 'g';
  	vfd[7] = ' ';
  	vfd[8] = '.';
  	vfd[9] = '.';
  	vfd[10] = '.';
  #endif /* !MODULE */
  
  	update_vfd();
  
  	return 0;
  }
  
  static void __exit briq_panel_exit(void)
  {
  	misc_deregister(&briq_panel_miscdev);
  	release_region(BRIQ_PANEL_VFD_IOPORT, 4);
  	release_region(BRIQ_PANEL_LED_IOPORT, 2);
  }
  
  module_init(briq_panel_init);
  module_exit(briq_panel_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Karsten Jeppesen <karsten@jeppesens.com>");
  MODULE_DESCRIPTION("Driver for the Total Impact briQ front panel");