drivers/video/arcfb.c

   1 /*
   2  * linux/drivers/video/arcfb.c -- FB driver for Arc monochrome LCD board
   3  *
   4  * Copyright (C) 2005, Jaya Kumar <jayalk@intworks.biz>
   5  * http://www.intworks.biz/arclcd
   6  *
   7  * This file is subject to the terms and conditions of the GNU General Public
   8  * License. See the file COPYING in the main directory of this archive for
   9  * more details.
  10  *
  11  * Layout is based on skeletonfb.c by James Simmons and Geert Uytterhoeven.
  12  *
  13  * This driver was written to be used with the Arc LCD board. Arc uses a
  14  * set of KS108 chips that control individual 64x64 LCD matrices. The board
  15  * can be paneled in a variety of setups such as 2x1=128x64, 4x4=256x256 and
  16  * so on. The interface between the board and the host is TTL based GPIO. The
  17  * GPIO requirements are 8 writable data lines and 4+n lines for control. On a
  18  * GPIO-less system, the board can be tested by connecting the respective sigs
  19  * up to a parallel port connector. The driver requires the IO addresses for
  20  * data and control GPIO at load time. It is unable to probe for the
  21  * existence of the LCD so it must be told at load time whether it should
  22  * be enabled or not.
  23  *
  24  * Todo:
  25  * - testing with 4x4
  26  * - testing with interrupt hw
  27  *
  28  * General notes:
  29  * - User must set tuhold. It's in microseconds. According to the 108 spec,
  30  *   the hold time is supposed to be at least 1 microsecond.
  31  * - User must set num_cols=x num_rows=y, eg: x=2 means 128
  32  * - User must set arcfb_enable=1 to enable it
  33  * - User must set dio_addr=0xIOADDR cio_addr=0xIOADDR
  34  *
  35  */
  36
  37 #include <linux/module.h>
  38 #include <linux/kernel.h>
  39 #include <linux/errno.h>
  40 #include <linux/string.h>
  41 #include <linux/mm.h>
  42 #include <linux/tty.h>
  43 #include <linux/slab.h>
  44 #include <linux/vmalloc.h>
  45 #include <linux/delay.h>
  46 #include <linux/interrupt.h>
  47 #include <linux/fb.h>
  48 #include <linux/init.h>
  49 #include <linux/arcfb.h>
  50
  51 #include <asm/uaccess.h>
  52
  53 #define floor8(a) (a&(~0x07))
  54 #define floorXres(a,xres) (a&(~(xres - 1)))
  55 #define iceil8(a) (((int)((a+7)/8))*8)
  56 #define ceil64(a) (a|0x3F)
  57 #define ceilXres(a,xres) (a|(xres - 1))
  58
  59 /* ks108 chipset specific defines and code */
  60
  61 #define KS_SET_DPY_START_LINE   0xC0
  62 #define KS_SET_PAGE_NUM         0xB8
  63 #define KS_SET_X                0x40
  64 #define KS_CEHI                 0x01
  65 #define KS_CELO                 0x00
  66 #define KS_SEL_CMD              0x08
  67 #define KS_SEL_DATA             0x00
  68 #define KS_DPY_ON               0x3F
  69 #define KS_DPY_OFF              0x3E
  70 #define KS_INTACK               0x40
  71 #define KS_CLRINT               0x02
  72
  73 struct arcfb_par {
  74         unsigned long dio_addr;
  75         unsigned long cio_addr;
  76         unsigned long c2io_addr;
  77         atomic_t ref_count;
  78         unsigned char cslut[9];
  79         struct fb_info *info;
  80         unsigned int irq;
  81         spinlock_t lock;
  82 };
  83
  84 static struct fb_fix_screeninfo arcfb_fix __initdata = {
  85         .id =           "arcfb",
  86         .type =         FB_TYPE_PACKED_PIXELS,
  87         .visual =       FB_VISUAL_MONO01,
  88         .xpanstep =     0,
  89         .ypanstep =     1,
  90         .ywrapstep =    0,
  91         .accel =        FB_ACCEL_NONE,
  92 };
  93
  94 static struct fb_var_screeninfo arcfb_var __initdata = {
  95         .xres           = 128,
  96         .yres           = 64,
  97         .xres_virtual   = 128,
  98         .yres_virtual   = 64,
  99         .bits_per_pixel = 1,
 100         .nonstd         = 1,
 101 };
 102
 103 static unsigned long num_cols;
 104 static unsigned long num_rows;
 105 static unsigned long dio_addr;
 106 static unsigned long cio_addr;
 107 static unsigned long c2io_addr;
 108 static unsigned long splashval;
 109 static unsigned long tuhold;
 110 static unsigned int nosplash;
 111 static unsigned int arcfb_enable;
 112 static unsigned int irq;
 113
 114 static DECLARE_WAIT_QUEUE_HEAD(arcfb_waitq);
 115
 116 static void ks108_writeb_ctl(struct arcfb_par *par,
 117                                 unsigned int chipindex, unsigned char value)
 118 {
 119         unsigned char chipselval = par->cslut[chipindex];
 120
 121         outb(chipselval|KS_CEHI|KS_SEL_CMD, par->cio_addr);
 122         outb(value, par->dio_addr);
 123         udelay(tuhold);
 124         outb(chipselval|KS_CELO|KS_SEL_CMD, par->cio_addr);
 125 }
 126
 127 static void ks108_writeb_mainctl(struct arcfb_par *par, unsigned char value)
 128 {
 129
 130         outb(value, par->cio_addr);
 131         udelay(tuhold);
 132 }
 133
 134 static unsigned char ks108_readb_ctl2(struct arcfb_par *par)
 135 {
 136         return inb(par->c2io_addr);
 137 }
 138
 139 static void ks108_writeb_data(struct arcfb_par *par,
 140                                 unsigned int chipindex, unsigned char value)
 141 {
 142         unsigned char chipselval = par->cslut[chipindex];
 143
 144         outb(chipselval|KS_CEHI|KS_SEL_DATA, par->cio_addr);
 145         outb(value, par->dio_addr);
 146         udelay(tuhold);
 147         outb(chipselval|KS_CELO|KS_SEL_DATA, par->cio_addr);
 148 }
 149
 150 static void ks108_set_start_line(struct arcfb_par *par,
 151                                 unsigned int chipindex, unsigned char y)
 152 {
 153         ks108_writeb_ctl(par, chipindex, KS_SET_DPY_START_LINE|y);
 154 }
 155
 156 static void ks108_set_yaddr(struct arcfb_par *par,
 157                                 unsigned int chipindex, unsigned char y)
 158 {
 159         ks108_writeb_ctl(par, chipindex, KS_SET_PAGE_NUM|y);
 160 }
 161
 162 static void ks108_set_xaddr(struct arcfb_par *par,
 163                                 unsigned int chipindex, unsigned char x)
 164 {
 165         ks108_writeb_ctl(par, chipindex, KS_SET_X|x);
 166 }
 167
 168 static void ks108_clear_lcd(struct arcfb_par *par, unsigned int chipindex)
 169 {
 170         int i,j;
 171
 172         for (i = 0; i <= 8; i++) {
 173                 ks108_set_yaddr(par, chipindex, i);
 174                 ks108_set_xaddr(par, chipindex, 0);
 175                 for (j = 0; j < 64; j++) {
 176                         ks108_writeb_data(par, chipindex,
 177                                 (unsigned char) splashval);
 178                 }
 179         }
 180 }
 181
 182 /* main arcfb functions */
 183
 184 static int arcfb_open(struct fb_info *info, int user)
 185 {
 186         struct arcfb_par *par = info->par;
 187
 188         atomic_inc(&par->ref_count);
 189         return 0;
 190 }
 191
 192 static int arcfb_release(struct fb_info *info, int user)
 193 {
 194         struct arcfb_par *par = info->par;
 195         int count = atomic_read(&par->ref_count);
 196
 197         if (!count)
 198                 return -EINVAL;
 199         atomic_dec(&par->ref_count);
 200         return 0;
 201 }
 202
 203 static int arcfb_pan_display(struct fb_var_screeninfo *var,
 204                                 struct fb_info *info)
 205 {
 206         int i;
 207         struct arcfb_par *par = info->par;
 208
 209         if ((var->vmode & FB_VMODE_YWRAP) && (var->yoffset < 64)
 210                 && (info->var.yres <= 64)) {
 211                 for (i = 0; i < num_cols; i++) {
 212                         ks108_set_start_line(par, i, var->yoffset);
 213                 }
 214                 info->var.yoffset = var->yoffset;
 215                 return 0;
 216         }
 217
 218         return -EINVAL;
 219 }
 220
 221 static irqreturn_t arcfb_interrupt(int vec, void *dev_instance,
 222                 struct pt_regs *regs)
 223 {
 224         struct fb_info *info = dev_instance;
 225         unsigned char ctl2status;
 226         struct arcfb_par *par = info->par;
 227
 228         ctl2status = ks108_readb_ctl2(par);
 229
 230         if (!(ctl2status & KS_INTACK)) /* not arc generated interrupt */
 231                 return IRQ_NONE;
 232
 233         ks108_writeb_mainctl(par, KS_CLRINT);
 234
 235         spin_lock(&par->lock);
 236         if (waitqueue_active(&arcfb_waitq)) {
 237                 wake_up(&arcfb_waitq);
 238         }
 239         spin_unlock(&par->lock);
 240
 241         return IRQ_HANDLED;
 242 }
 243
 244 /*
 245  * here we handle a specific page on the lcd. the complexity comes from
 246  * the fact that the fb is laidout in 8xX vertical columns. we extract
 247  * each write of 8 vertical pixels. then we shift out as we move along
 248  * X. That's what rightshift does. bitmask selects the desired input bit.
 249  */
 250 static void arcfb_lcd_update_page(struct arcfb_par *par, unsigned int upper,
 251                 unsigned int left, unsigned int right, unsigned int distance)
 252 {
 253         unsigned char *src;
 254         unsigned int xindex, yindex, chipindex, linesize;
 255         int i, count;
 256         unsigned char val;
 257         unsigned char bitmask, rightshift;
 258
 259         xindex = left >> 6;
 260         yindex = upper >> 6;
 261         chipindex = (xindex + (yindex*num_cols));
 262
 263         ks108_set_yaddr(par, chipindex, upper/8);
 264
 265         linesize = par->info->var.xres/8;
 266         src = par->info->screen_base + (left/8) + (upper * linesize);
 267         ks108_set_xaddr(par, chipindex, left);
 268
 269         bitmask=1;
 270         rightshift=0;
 271         while (left <= right) {
 272                 val = 0;
 273                 for (i = 0; i < 8; i++) {
 274                         if ( i > rightshift) {
 275                                 val |= (*(src + (i*linesize)) & bitmask)
 276                                                 << (i - rightshift);
 277                         } else {
 278                                 val |= (*(src + (i*linesize)) & bitmask)
 279                                                  >> (rightshift - i);
 280                         }
 281                 }
 282                 ks108_writeb_data(par, chipindex, val);
 283                 left++;
 284                 count++;
 285                 if (bitmask == 0x80) {
 286                         bitmask = 1;
 287                         src++;
 288                         rightshift=0;
 289                 } else {
 290                         bitmask <<= 1;
 291                         rightshift++;
 292                 }
 293         }
 294 }
 295
 296 /*
 297  * here we handle the entire vertical page of the update. we write across
 298  * lcd chips. update_page uses the upper/left values to decide which
 299  * chip to select for the right. upper is needed for setting the page
 300  * desired for the write.
 301  */
 302 static void arcfb_lcd_update_vert(struct arcfb_par *par, unsigned int top,
 303                 unsigned int bottom, unsigned int left, unsigned int right)
 304 {
 305         unsigned int distance, upper, lower;
 306
 307         distance = (bottom - top) + 1;
 308         upper = top;
 309         lower = top + 7;
 310
 311         while (distance > 0) {
 312                 distance -= 8;
 313                 arcfb_lcd_update_page(par, upper, left, right, 8);
 314                 upper = lower + 1;
 315                 lower = upper + 7;
 316         }
 317 }
 318
 319 /*
 320  * here we handle horizontal blocks for the update. update_vert will
 321  * handle spaning multiple pages. we break out each horizontal
 322  * block in to individual blocks no taller than 64 pixels.
 323  */
 324 static void arcfb_lcd_update_horiz(struct arcfb_par *par, unsigned int left,
 325                         unsigned int right, unsigned int top, unsigned int h)
 326 {
 327         unsigned int distance, upper, lower;
 328
 329         distance = h;
 330         upper = floor8(top);
 331         lower = min(upper + distance - 1, ceil64(upper));
 332
 333         while (distance > 0) {
 334                 distance -= ((lower - upper) + 1 );
 335                 arcfb_lcd_update_vert(par, upper, lower, left, right);
 336                 upper = lower + 1;
 337                 lower = min(upper + distance - 1, ceil64(upper));
 338         }
 339 }
 340
 341 /*
 342  * here we start the process of spliting out the fb update into
 343  * individual blocks of pixels. we end up spliting into 64x64 blocks
 344  * and finally down to 64x8 pages.
 345  */
 346 static void arcfb_lcd_update(struct arcfb_par *par, unsigned int dx,
 347                         unsigned int dy, unsigned int w, unsigned int h)
 348 {
 349         unsigned int left, right, distance, y;
 350
 351         /* align the request first */
 352         y = floor8(dy);
 353         h += dy - y;
 354         h = iceil8(h);
 355
 356         distance = w;
 357         left = dx;
 358         right = min(left + w - 1, ceil64(left));
 359
 360         while (distance > 0) {
 361                 arcfb_lcd_update_horiz(par, left, right, y, h);
 362                 distance -= ((right - left) + 1);
 363                 left = right + 1;
 364                 right = min(left + distance - 1, ceil64(left));
 365         }
 366 }
 367
 368 void arcfb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
 369 {
 370         struct arcfb_par *par = info->par;
 371
 372         cfb_fillrect(info, rect);
 373
 374         /* update the physical lcd */
 375         arcfb_lcd_update(par, rect->dx, rect->dy, rect->width, rect->height);
 376 }
 377
 378 void arcfb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
 379 {
 380         struct arcfb_par *par = info->par;
 381
 382         cfb_copyarea(info, area);
 383
 384         /* update the physical lcd */
 385         arcfb_lcd_update(par, area->dx, area->dy, area->width, area->height);
 386 }
 387
 388 void arcfb_imageblit(struct fb_info *info, const struct fb_image *image)
 389 {
 390         struct arcfb_par *par = info->par;
 391
 392         cfb_imageblit(info, image);
 393
 394         /* update the physical lcd */
 395         arcfb_lcd_update(par, image->dx, image->dy, image->width,
 396                                 image->height);
 397 }
 398
 399 static int arcfb_ioctl(struct inode *inode, struct file *file,
 400                           unsigned int cmd, unsigned long arg,
 401                           struct fb_info *info)
 402 {
 403         void __user *argp = (void __user *)arg;
 404         struct arcfb_par *par = info->par;
 405         unsigned long flags;
 406
 407         switch (cmd) {
 408                 case FBIO_WAITEVENT:
 409                 {
 410                         DEFINE_WAIT(wait);
 411                         /* illegal to wait on arc if no irq will occur */
 412                         if (!par->irq)
 413                                 return -EINVAL;
 414
 415                         /* wait until the Arc has generated an interrupt
 416                          * which will wake us up */
 417                         spin_lock_irqsave(&par->lock, flags);
 418                         prepare_to_wait(&arcfb_waitq, &wait,
 419                                         TASK_INTERRUPTIBLE);
 420                         spin_unlock_irqrestore(&par->lock, flags);
 421                         schedule();
 422                         finish_wait(&arcfb_waitq, &wait);
 423                 }
 424                 case FBIO_GETCONTROL2:
 425                 {
 426                         unsigned char ctl2;
 427
 428                         ctl2 = ks108_readb_ctl2(info->par);
 429                         if (copy_to_user(argp, &ctl2, sizeof(ctl2)))
 430                                 return -EFAULT;
 431                         return 0;
 432                 }
 433                 default:
 434                         return -EINVAL;
 435         }
 436 }
 437
 438 /*
 439  * this is the access path from userspace. they can seek and write to
 440  * the fb. it's inefficient for them to do anything less than 64*8
 441  * writes since we update the lcd in each write() anyway.
 442  */
 443 static ssize_t arcfb_write(struct file *file, const char *buf, size_t count,
 444                                 loff_t *ppos)
 445 {
 446         /* modded from epson 1355 */
 447
 448         struct inode *inode;
 449         int fbidx;
 450         struct fb_info *info;
 451         unsigned long p;
 452         int err=-EINVAL;
 453         unsigned int fbmemlength,x,y,w,h, bitppos, startpos, endpos, bitcount;
 454         struct arcfb_par *par;
 455         unsigned int xres;
 456
 457         p = *ppos;
 458         inode = file->f_dentry->d_inode;
 459         fbidx = iminor(inode);
 460         info = registered_fb[fbidx];
 461         par = info->par;
 462
 463         if (!info || !info->screen_base)
 464                 return -ENODEV;
 465
 466         xres = info->var.xres;
 467         fbmemlength = (xres * info->var.yres)/8;
 468
 469         if (p > fbmemlength)
 470                 return -ENOSPC;
 471
 472         err = 0;
 473         if ((count + p) > fbmemlength) {
 474                 count = fbmemlength - p;
 475                 err = -ENOSPC;
 476         }
 477
 478         if (count) {
 479                 char *base_addr;
 480
 481                 base_addr = info->screen_base;
 482                 count -= copy_from_user(base_addr + p, buf, count);
 483                 *ppos += count;
 484                 err = -EFAULT;
 485         }
 486
 487
 488         bitppos = p*8;
 489         startpos = floorXres(bitppos, xres);
 490         endpos = ceilXres((bitppos + (count*8)), xres);
 491         bitcount = endpos - startpos;
 492
 493         x = startpos % xres;
 494         y = startpos / xres;
 495         w = xres;
 496         h = bitcount / xres;
 497         arcfb_lcd_update(par, x, y, w, h);
 498
 499         if (count)
 500                 return count;
 501         return err;
 502 }
 503
 504 static void arcfb_platform_release(struct device *device)
 505 {
 506 }
 507
 508 static struct fb_ops arcfb_ops = {
 509         .owner          = THIS_MODULE,
 510         .fb_open        = arcfb_open,
 511         .fb_write       = arcfb_write,
 512         .fb_release     = arcfb_release,
 513         .fb_pan_display = arcfb_pan_display,
 514         .fb_fillrect    = arcfb_fillrect,
 515         .fb_copyarea    = arcfb_copyarea,
 516         .fb_imageblit   = arcfb_imageblit,
 517         .fb_cursor      = soft_cursor,
 518         .fb_ioctl       = arcfb_ioctl,
 519 };
 520
 521 static int __init arcfb_probe(struct device *device)
 522 {
 523         struct platform_device *dev = to_platform_device(device);
 524         struct fb_info *info;
 525         int retval = -ENOMEM;
 526         int videomemorysize;
 527         unsigned char *videomemory;
 528         struct arcfb_par *par;
 529         int i;
 530
 531         videomemorysize = (((64*64)*num_cols)*num_rows)/8;
 532
 533         /* We need a flat backing store for the Arc's
 534            less-flat actual paged framebuffer */
 535         if (!(videomemory = vmalloc(videomemorysize)))
 536                 return retval;
 537
 538         memset(videomemory, 0, videomemorysize);
 539
 540         info = framebuffer_alloc(sizeof(struct arcfb_par), &dev->dev);
 541         if (!info)
 542                 goto err;
 543
 544         info->screen_base = (char __iomem *)videomemory;
 545         info->fbops = &arcfb_ops;
 546
 547         info->var = arcfb_var;
 548         info->fix = arcfb_fix;
 549         par = info->par;
 550         par->info = info;
 551
 552         if (!dio_addr || !cio_addr || !c2io_addr) {
 553                 printk(KERN_WARNING "no IO addresses supplied\n");
 554                 goto err1;
 555         }
 556         par->dio_addr = dio_addr;
 557         par->cio_addr = cio_addr;
 558         par->c2io_addr = c2io_addr;
 559         par->cslut[0] = 0x00;
 560         par->cslut[1] = 0x06;
 561         info->flags = FBINFO_FLAG_DEFAULT;
 562         spin_lock_init(&par->lock);
 563         retval = register_framebuffer(info);
 564         if (retval < 0)
 565                 goto err1;
 566         dev_set_drvdata(&dev->dev, info);
 567         if (irq) {
 568                 par->irq = irq;
 569                 if (request_irq(par->irq, &arcfb_interrupt, SA_SHIRQ,
 570                                 "arcfb", info)) {
 571                         printk(KERN_INFO
 572                                 "arcfb: Failed req IRQ %d\n", par->irq);
 573                         goto err1;
 574                 }
 575         }
 576         printk(KERN_INFO
 577                "fb%d: Arc frame buffer device, using %dK of video memory\n",
 578                info->node, videomemorysize >> 10);
 579
 580         /* this inits the lcd but doesn't clear dirty pixels */
 581         for (i = 0; i < num_cols * num_rows; i++) {
 582                 ks108_writeb_ctl(par, i, KS_DPY_OFF);
 583                 ks108_set_start_line(par, i, 0);
 584                 ks108_set_yaddr(par, i, 0);
 585                 ks108_set_xaddr(par, i, 0);
 586                 ks108_writeb_ctl(par, i, KS_DPY_ON);
 587         }
 588
 589         /* if we were told to splash the screen, we just clear it */
 590         if (!nosplash) {
 591                 for (i = 0; i < num_cols * num_rows; i++) {
 592                         printk(KERN_INFO "fb%d: splashing lcd %d\n",
 593                                 info->node, i);
 594                         ks108_set_start_line(par, i, 0);
 595                         ks108_clear_lcd(par, i);
 596                 }
 597         }
 598
 599         return 0;
 600 err1:
 601         framebuffer_release(info);
 602 err:
 603         vfree(videomemory);
 604         return retval;
 605 }
 606
 607 static int arcfb_remove(struct device *device)
 608 {
 609         struct fb_info *info = dev_get_drvdata(device);
 610
 611         if (info) {
 612                 unregister_framebuffer(info);
 613                 vfree(info->screen_base);
 614                 framebuffer_release(info);
 615         }
 616         return 0;
 617 }
 618
 619 static struct device_driver arcfb_driver = {
 620         .name   = "arcfb",
 621         .bus    = &platform_bus_type,
 622         .probe  = arcfb_probe,
 623         .remove = arcfb_remove,
 624 };
 625
 626 static struct platform_device arcfb_device = {
 627         .name   = "arcfb",
 628         .id     = 0,
 629         .dev    = {
 630                 .release = arcfb_platform_release,
 631         }
 632 };
 633
 634 static int __init arcfb_init(void)
 635 {
 636         int ret;
 637
 638         if (!arcfb_enable)
 639                 return -ENXIO;
 640
 641         ret = driver_register(&arcfb_driver);
 642         if (!ret) {
 643                 ret = platform_device_register(&arcfb_device);
 644                 if (ret)
 645                         driver_unregister(&arcfb_driver);
 646         }
 647         return ret;
 648
 649 }
 650
 651 static void __exit arcfb_exit(void)
 652 {
 653         platform_device_unregister(&arcfb_device);
 654         driver_unregister(&arcfb_driver);
 655 }
 656
 657 module_param(num_cols, ulong, 0);
 658 MODULE_PARM_DESC(num_cols, "Num horiz panels, eg: 2 = 128 bit wide");
 659 module_param(num_rows, ulong, 0);
 660 MODULE_PARM_DESC(num_rows, "Num vert panels, eg: 1 = 64 bit high");
 661 module_param(nosplash, uint, 0);
 662 MODULE_PARM_DESC(nosplash, "Disable doing the splash screen");
 663 module_param(arcfb_enable, uint, 0);
 664 MODULE_PARM_DESC(arcfb_enable, "Enable communication with Arc board");
 665 module_param(dio_addr, ulong, 0);
 666 MODULE_PARM_DESC(dio_addr, "IO address for data, eg: 0x480");
 667 module_param(cio_addr, ulong, 0);
 668 MODULE_PARM_DESC(cio_addr, "IO address for control, eg: 0x400");
 669 module_param(c2io_addr, ulong, 0);
 670 MODULE_PARM_DESC(c2io_addr, "IO address for secondary control, eg: 0x408");
 671 module_param(splashval, ulong, 0);
 672 MODULE_PARM_DESC(splashval, "Splash pattern: 0xFF is black, 0x00 is green");
 673 module_param(tuhold, ulong, 0);
 674 MODULE_PARM_DESC(tuhold, "Time to hold between strobing data to Arc board");
 675 module_param(irq, uint, 0);
 676 MODULE_PARM_DESC(irq, "IRQ for the Arc board");
 677
 678 module_init(arcfb_init);
 679 module_exit(arcfb_exit);
 680
 681 MODULE_DESCRIPTION("fbdev driver for Arc monochrome LCD board");
 682 MODULE_AUTHOR("Jaya Kumar");
 683 MODULE_LICENSE("GPL");
 684