drivers/video/msm/msm_fb.c

   1 /* drivers/video/msm/msm_fb.c
   2  *
   3  * Core MSM framebuffer driver.
   4  *
   5  * Copyright (C) 2007 Google Incorporated
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include <linux/platform_device.h>
  18 #include <linux/module.h>
  19 #include <linux/fb.h>
  20 #include <linux/slab.h>
  21 #include <linux/delay.h>
  22
  23 #include <linux/freezer.h>
  24 #include <linux/wait.h>
  25 #include <linux/msm_mdp.h>
  26 #include <linux/io.h>
  27 #include <linux/uaccess.h>
  28 #include <mach/msm_fb.h>
  29 #include <mach/board.h>
  30 #include <linux/workqueue.h>
  31 #include <linux/clk.h>
  32 #include <linux/debugfs.h>
  33 #include <linux/dma-mapping.h>
  34
  35 #define PRINT_FPS 0
  36 #define PRINT_BLIT_TIME 0
  37
  38 #define SLEEPING 0x4
  39 #define UPDATING 0x3
  40 #define FULL_UPDATE_DONE 0x2
  41 #define WAKING 0x1
  42 #define AWAKE 0x0
  43
  44 #define NONE 0
  45 #define SUSPEND_RESUME 0x1
  46 #define FPS 0x2
  47 #define BLIT_TIME 0x4
  48 #define SHOW_UPDATES 0x8
  49
  50 #define DLOG(mask, fmt, args...) \
  51 do { \
  52         if (msmfb_debug_mask & mask) \
  53                 printk(KERN_INFO "msmfb: "fmt, ##args); \
  54 } while (0)
  55
  56 static int msmfb_debug_mask;
  57 module_param_named(msmfb_debug_mask, msmfb_debug_mask, int,
  58                    S_IRUGO | S_IWUSR | S_IWGRP);
  59
  60 struct mdp_device *mdp;
  61
  62 struct msmfb_info {
  63         struct fb_info *fb;
  64         struct msm_panel_data *panel;
  65         int xres;
  66         int yres;
  67         unsigned output_format;
  68         unsigned yoffset;
  69         unsigned frame_requested;
  70         unsigned frame_done;
  71         int sleeping;
  72         unsigned update_frame;
  73         struct {
  74                 int left;
  75                 int top;
  76                 int eright; /* exclusive */
  77                 int ebottom; /* exclusive */
  78         } update_info;
  79         char *black;
  80
  81         spinlock_t update_lock;
  82         struct mutex panel_init_lock;
  83         wait_queue_head_t frame_wq;
  84         struct workqueue_struct *resume_workqueue;
  85         struct work_struct resume_work;
  86         struct msmfb_callback dma_callback;
  87         struct msmfb_callback vsync_callback;
  88         struct hrtimer fake_vsync;
  89         ktime_t vsync_request_time;
  90 };
  91
  92 static int msmfb_open(struct fb_info *info, int user)
  93 {
  94         return 0;
  95 }
  96
  97 static int msmfb_release(struct fb_info *info, int user)
  98 {
  99         return 0;
 100 }
 101
 102 /* Called from dma interrupt handler, must not sleep */
 103 static void msmfb_handle_dma_interrupt(struct msmfb_callback *callback)
 104 {
 105         unsigned long irq_flags;
 106         struct msmfb_info *msmfb  = container_of(callback, struct msmfb_info,
 107                                                dma_callback);
 108
 109         spin_lock_irqsave(&msmfb->update_lock, irq_flags);
 110         msmfb->frame_done = msmfb->frame_requested;
 111         if (msmfb->sleeping == UPDATING &&
 112             msmfb->frame_done == msmfb->update_frame) {
 113                 DLOG(SUSPEND_RESUME, "full update completed\n");
 114                 queue_work(msmfb->resume_workqueue, &msmfb->resume_work);
 115         }
 116         spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 117         wake_up(&msmfb->frame_wq);
 118 }
 119
 120 static int msmfb_start_dma(struct msmfb_info *msmfb)
 121 {
 122         uint32_t x, y, w, h;
 123         unsigned addr;
 124         unsigned long irq_flags;
 125         uint32_t yoffset;
 126         s64 time_since_request;
 127         struct msm_panel_data *panel = msmfb->panel;
 128
 129         spin_lock_irqsave(&msmfb->update_lock, irq_flags);
 130         time_since_request = ktime_to_ns(ktime_sub(ktime_get(),
 131                              msmfb->vsync_request_time));
 132         if (time_since_request > 20 * NSEC_PER_MSEC) {
 133                 uint32_t us;
 134                 us = do_div(time_since_request, NSEC_PER_MSEC) / NSEC_PER_USEC;
 135                 printk(KERN_WARNING "msmfb_start_dma %lld.%03u ms after vsync "
 136                         "request\n", time_since_request, us);
 137         }
 138         if (msmfb->frame_done == msmfb->frame_requested) {
 139                 spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 140                 return -1;
 141         }
 142         if (msmfb->sleeping == SLEEPING) {
 143                 DLOG(SUSPEND_RESUME, "tried to start dma while asleep\n");
 144                 spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 145                 return -1;
 146         }
 147         x = msmfb->update_info.left;
 148         y = msmfb->update_info.top;
 149         w = msmfb->update_info.eright - x;
 150         h = msmfb->update_info.ebottom - y;
 151         yoffset = msmfb->yoffset;
 152         msmfb->update_info.left = msmfb->xres + 1;
 153         msmfb->update_info.top = msmfb->yres + 1;
 154         msmfb->update_info.eright = 0;
 155         msmfb->update_info.ebottom = 0;
 156         if (unlikely(w > msmfb->xres || h > msmfb->yres ||
 157                      w == 0 || h == 0)) {
 158                 printk(KERN_INFO "invalid update: %d %d %d "
 159                                 "%d\n", x, y, w, h);
 160                 msmfb->frame_done = msmfb->frame_requested;
 161                 goto error;
 162         }
 163         spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 164
 165         addr = ((msmfb->xres * (yoffset + y) + x) * 2);
 166         mdp->dma(mdp, addr + msmfb->fb->fix.smem_start,
 167                  msmfb->xres * 2, w, h, x, y, &msmfb->dma_callback,
 168                  panel->interface_type);
 169         return 0;
 170 error:
 171         spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 172         /* some clients need to clear their vsync interrupt */
 173         if (panel->clear_vsync)
 174                 panel->clear_vsync(panel);
 175         wake_up(&msmfb->frame_wq);
 176         return 0;
 177 }
 178
 179 /* Called from esync interrupt handler, must not sleep */
 180 static void msmfb_handle_vsync_interrupt(struct msmfb_callback *callback)
 181 {
 182         struct msmfb_info *msmfb = container_of(callback, struct msmfb_info,
 183                                                vsync_callback);
 184         msmfb_start_dma(msmfb);
 185 }
 186
 187 static enum hrtimer_restart msmfb_fake_vsync(struct hrtimer *timer)
 188 {
 189         struct msmfb_info *msmfb  = container_of(timer, struct msmfb_info,
 190                                                fake_vsync);
 191         msmfb_start_dma(msmfb);
 192         return HRTIMER_NORESTART;
 193 }
 194
 195 static void msmfb_pan_update(struct fb_info *info, uint32_t left, uint32_t top,
 196                              uint32_t eright, uint32_t ebottom,
 197                              uint32_t yoffset, int pan_display)
 198 {
 199         struct msmfb_info *msmfb = info->par;
 200         struct msm_panel_data *panel = msmfb->panel;
 201         unsigned long irq_flags;
 202         int sleeping;
 203         int retry = 1;
 204
 205         DLOG(SHOW_UPDATES, "update %d %d %d %d %d %d\n",
 206                 left, top, eright, ebottom, yoffset, pan_display);
 207 restart:
 208         spin_lock_irqsave(&msmfb->update_lock, irq_flags);
 209
 210         /* if we are sleeping, on a pan_display wait 10ms (to throttle back
 211          * drawing otherwise return */
 212         if (msmfb->sleeping == SLEEPING) {
 213                 DLOG(SUSPEND_RESUME, "drawing while asleep\n");
 214                 spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 215                 if (pan_display)
 216                         wait_event_interruptible_timeout(msmfb->frame_wq,
 217                                 msmfb->sleeping != SLEEPING, HZ/10);
 218                 return;
 219         }
 220
 221         sleeping = msmfb->sleeping;
 222         /* on a full update, if the last frame has not completed, wait for it */
 223         if (pan_display && (msmfb->frame_requested != msmfb->frame_done ||
 224                             sleeping == UPDATING)) {
 225                 int ret;
 226                 spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 227                 ret = wait_event_interruptible_timeout(msmfb->frame_wq,
 228                         msmfb->frame_done == msmfb->frame_requested &&
 229                         msmfb->sleeping != UPDATING, 5 * HZ);
 230                 if (ret <= 0 && (msmfb->frame_requested != msmfb->frame_done ||
 231                                  msmfb->sleeping == UPDATING)) {
 232                         if (retry && panel->request_vsync &&
 233                             (sleeping == AWAKE)) {
 234                                 panel->request_vsync(panel,
 235                                         &msmfb->vsync_callback);
 236                                 retry = 0;
 237                                 printk(KERN_WARNING "msmfb_pan_display timeout "
 238                                         "rerequest vsync\n");
 239                         } else {
 240                                 printk(KERN_WARNING "msmfb_pan_display timeout "
 241                                         "waiting for frame start, %d %d\n",
 242                                         msmfb->frame_requested,
 243                                         msmfb->frame_done);
 244                                 return;
 245                         }
 246                 }
 247                 goto restart;
 248         }
 249
 250
 251         msmfb->frame_requested++;
 252         /* if necessary, update the y offset, if this is the
 253          * first full update on resume, set the sleeping state */
 254         if (pan_display) {
 255                 msmfb->yoffset = yoffset;
 256                 if (left == 0 && top == 0 && eright == info->var.xres &&
 257                     ebottom == info->var.yres) {
 258                         if (sleeping == WAKING) {
 259                                 msmfb->update_frame = msmfb->frame_requested;
 260                                 DLOG(SUSPEND_RESUME, "full update starting\n");
 261                                 msmfb->sleeping = UPDATING;
 262                         }
 263                 }
 264         }
 265
 266         /* set the update request */
 267         if (left < msmfb->update_info.left)
 268                 msmfb->update_info.left = left;
 269         if (top < msmfb->update_info.top)
 270                 msmfb->update_info.top = top;
 271         if (eright > msmfb->update_info.eright)
 272                 msmfb->update_info.eright = eright;
 273         if (ebottom > msmfb->update_info.ebottom)
 274                 msmfb->update_info.ebottom = ebottom;
 275         DLOG(SHOW_UPDATES, "update queued %d %d %d %d %d\n",
 276                 msmfb->update_info.left, msmfb->update_info.top,
 277                 msmfb->update_info.eright, msmfb->update_info.ebottom,
 278                 msmfb->yoffset);
 279         spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 280
 281         /* if the panel is all the way on wait for vsync, otherwise sleep
 282          * for 16 ms (long enough for the dma to panel) and then begin dma */
 283         msmfb->vsync_request_time = ktime_get();
 284         if (panel->request_vsync && (sleeping == AWAKE)) {
 285                 panel->request_vsync(panel, &msmfb->vsync_callback);
 286         } else {
 287                 if (!hrtimer_active(&msmfb->fake_vsync)) {
 288                         hrtimer_start(&msmfb->fake_vsync,
 289                                       ktime_set(0, NSEC_PER_SEC/60),
 290                                       HRTIMER_MODE_REL);
 291                 }
 292         }
 293 }
 294
 295 static void msmfb_update(struct fb_info *info, uint32_t left, uint32_t top,
 296                          uint32_t eright, uint32_t ebottom)
 297 {
 298         msmfb_pan_update(info, left, top, eright, ebottom, 0, 0);
 299 }
 300
 301 static void power_on_panel(struct work_struct *work)
 302 {
 303         struct msmfb_info *msmfb =
 304                 container_of(work, struct msmfb_info, resume_work);
 305         struct msm_panel_data *panel = msmfb->panel;
 306         unsigned long irq_flags;
 307
 308         mutex_lock(&msmfb->panel_init_lock);
 309         DLOG(SUSPEND_RESUME, "turning on panel\n");
 310         if (msmfb->sleeping == UPDATING) {
 311                 if (panel->unblank(panel)) {
 312                         printk(KERN_INFO "msmfb: panel unblank failed,"
 313                                "not starting drawing\n");
 314                         goto error;
 315                 }
 316                 spin_lock_irqsave(&msmfb->update_lock, irq_flags);
 317                 msmfb->sleeping = AWAKE;
 318                 wake_up(&msmfb->frame_wq);
 319                 spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 320         }
 321 error:
 322         mutex_unlock(&msmfb->panel_init_lock);
 323 }
 324
 325
 326 static int msmfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
 327 {
 328         if ((var->xres != info->var.xres) ||
 329             (var->yres != info->var.yres) ||
 330             (var->xres_virtual != info->var.xres_virtual) ||
 331             (var->yres_virtual != info->var.yres_virtual) ||
 332             (var->xoffset != info->var.xoffset) ||
 333             (var->bits_per_pixel != info->var.bits_per_pixel) ||
 334             (var->grayscale != info->var.grayscale))
 335                  return -EINVAL;
 336         return 0;
 337 }
 338
 339 int msmfb_pan_display(struct fb_var_screeninfo *var, struct fb_info *info)
 340 {
 341         struct msmfb_info *msmfb = info->par;
 342         struct msm_panel_data *panel = msmfb->panel;
 343
 344         /* "UPDT" */
 345         if ((panel->caps & MSMFB_CAP_PARTIAL_UPDATES) &&
 346             (var->reserved[0] == 0x54445055)) {
 347                 msmfb_pan_update(info, var->reserved[1] & 0xffff,
 348                                  var->reserved[1] >> 16,
 349                                  var->reserved[2] & 0xffff,
 350                                  var->reserved[2] >> 16, var->yoffset, 1);
 351         } else {
 352                 msmfb_pan_update(info, 0, 0, info->var.xres, info->var.yres,
 353                                  var->yoffset, 1);
 354         }
 355         return 0;
 356 }
 357
 358 static void msmfb_fillrect(struct fb_info *p, const struct fb_fillrect *rect)
 359 {
 360         cfb_fillrect(p, rect);
 361         msmfb_update(p, rect->dx, rect->dy, rect->dx + rect->width,
 362                      rect->dy + rect->height);
 363 }
 364
 365 static void msmfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
 366 {
 367         cfb_copyarea(p, area);
 368         msmfb_update(p, area->dx, area->dy, area->dx + area->width,
 369                      area->dy + area->height);
 370 }
 371
 372 static void msmfb_imageblit(struct fb_info *p, const struct fb_image *image)
 373 {
 374         cfb_imageblit(p, image);
 375         msmfb_update(p, image->dx, image->dy, image->dx + image->width,
 376                      image->dy + image->height);
 377 }
 378
 379
 380 static int msmfb_blit(struct fb_info *info,
 381                       void __user *p)
 382 {
 383         struct mdp_blit_req req;
 384         struct mdp_blit_req_list req_list;
 385         int i;
 386         int ret;
 387
 388         if (copy_from_user(&req_list, p, sizeof(req_list)))
 389                 return -EFAULT;
 390
 391         for (i = 0; i < req_list.count; i++) {
 392                 struct mdp_blit_req_list *list =
 393                         (struct mdp_blit_req_list *)p;
 394                 if (copy_from_user(&req, &list->req[i], sizeof(req)))
 395                         return -EFAULT;
 396                 ret = mdp->blit(mdp, info, &req);
 397                 if (ret)
 398                         return ret;
 399         }
 400         return 0;
 401 }
 402
 403
 404 DEFINE_MUTEX(mdp_ppp_lock);
 405
 406 static int msmfb_ioctl(struct fb_info *p, unsigned int cmd, unsigned long arg)
 407 {
 408         void __user *argp = (void __user *)arg;
 409         int ret;
 410
 411         switch (cmd) {
 412         case MSMFB_GRP_DISP:
 413                 mdp->set_grp_disp(mdp, arg);
 414                 break;
 415         case MSMFB_BLIT:
 416                 ret = msmfb_blit(p, argp);
 417                 if (ret)
 418                         return ret;
 419                 break;
 420         default:
 421                         printk(KERN_INFO "msmfb unknown ioctl: %d\n", cmd);
 422                         return -EINVAL;
 423         }
 424         return 0;
 425 }
 426
 427 static struct fb_ops msmfb_ops = {
 428         .owner = THIS_MODULE,
 429         .fb_open = msmfb_open,
 430         .fb_release = msmfb_release,
 431         .fb_check_var = msmfb_check_var,
 432         .fb_pan_display = msmfb_pan_display,
 433         .fb_fillrect = msmfb_fillrect,
 434         .fb_copyarea = msmfb_copyarea,
 435         .fb_imageblit = msmfb_imageblit,
 436         .fb_ioctl = msmfb_ioctl,
 437 };
 438
 439 static unsigned PP[16];
 440
 441
 442
 443 #define BITS_PER_PIXEL 16
 444
 445 static void setup_fb_info(struct msmfb_info *msmfb)
 446 {
 447         struct fb_info *fb_info = msmfb->fb;
 448         int r;
 449
 450         /* finish setting up the fb_info struct */
 451         strncpy(fb_info->fix.id, "msmfb", 16);
 452         fb_info->fix.ypanstep = 1;
 453
 454         fb_info->fbops = &msmfb_ops;
 455         fb_info->flags = FBINFO_DEFAULT;
 456
 457         fb_info->fix.type = FB_TYPE_PACKED_PIXELS;
 458         fb_info->fix.visual = FB_VISUAL_TRUECOLOR;
 459         fb_info->fix.line_length = msmfb->xres * 2;
 460
 461         fb_info->var.xres = msmfb->xres;
 462         fb_info->var.yres = msmfb->yres;
 463         fb_info->var.width = msmfb->panel->fb_data->width;
 464         fb_info->var.height = msmfb->panel->fb_data->height;
 465         fb_info->var.xres_virtual = msmfb->xres;
 466         fb_info->var.yres_virtual = msmfb->yres * 2;
 467         fb_info->var.bits_per_pixel = BITS_PER_PIXEL;
 468         fb_info->var.accel_flags = 0;
 469
 470         fb_info->var.yoffset = 0;
 471
 472         if (msmfb->panel->caps & MSMFB_CAP_PARTIAL_UPDATES) {
 473                 fb_info->var.reserved[0] = 0x54445055;
 474                 fb_info->var.reserved[1] = 0;
 475                 fb_info->var.reserved[2] = (uint16_t)msmfb->xres |
 476                                            ((uint32_t)msmfb->yres << 16);
 477         }
 478
 479         fb_info->var.red.offset = 11;
 480         fb_info->var.red.length = 5;
 481         fb_info->var.red.msb_right = 0;
 482         fb_info->var.green.offset = 5;
 483         fb_info->var.green.length = 6;
 484         fb_info->var.green.msb_right = 0;
 485         fb_info->var.blue.offset = 0;
 486         fb_info->var.blue.length = 5;
 487         fb_info->var.blue.msb_right = 0;
 488
 489         r = fb_alloc_cmap(&fb_info->cmap, 16, 0);
 490         fb_info->pseudo_palette = PP;
 491
 492         PP[0] = 0;
 493         for (r = 1; r < 16; r++)
 494                 PP[r] = 0xffffffff;
 495 }
 496
 497 static int setup_fbmem(struct msmfb_info *msmfb, struct platform_device *pdev)
 498 {
 499         struct fb_info *fb = msmfb->fb;
 500         struct resource *resource;
 501         unsigned long size = msmfb->xres * msmfb->yres *
 502                              (BITS_PER_PIXEL >> 3) * 2;
 503         unsigned char *fbram;
 504
 505         /* board file might have attached a resource describing an fb */
 506         resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 507         if (!resource)
 508                 return -EINVAL;
 509
 510         /* check the resource is large enough to fit the fb */
 511         if (resource->end - resource->start < size) {
 512                 printk(KERN_ERR "allocated resource is too small for "
 513                                 "fb\n");
 514                 return -ENOMEM;
 515         }
 516         fb->fix.smem_start = resource->start;
 517         fb->fix.smem_len = resource->end - resource->start;
 518         fbram = ioremap(resource->start,
 519                         resource->end - resource->start);
 520         if (fbram == 0) {
 521                 printk(KERN_ERR "msmfb: cannot allocate fbram!\n");
 522                 return -ENOMEM;
 523         }
 524         fb->screen_base = fbram;
 525         return 0;
 526 }
 527
 528 static int msmfb_probe(struct platform_device *pdev)
 529 {
 530         struct fb_info *fb;
 531         struct msmfb_info *msmfb;
 532         struct msm_panel_data *panel = pdev->dev.platform_data;
 533         int ret;
 534
 535         if (!panel) {
 536                 pr_err("msmfb_probe: no platform data\n");
 537                 return -EINVAL;
 538         }
 539         if (!panel->fb_data) {
 540                 pr_err("msmfb_probe: no fb_data\n");
 541                 return -EINVAL;
 542         }
 543
 544         fb = framebuffer_alloc(sizeof(struct msmfb_info), &pdev->dev);
 545         if (!fb)
 546                 return -ENOMEM;
 547         msmfb = fb->par;
 548         msmfb->fb = fb;
 549         msmfb->panel = panel;
 550         msmfb->xres = panel->fb_data->xres;
 551         msmfb->yres = panel->fb_data->yres;
 552
 553         ret = setup_fbmem(msmfb, pdev);
 554         if (ret)
 555                 goto error_setup_fbmem;
 556
 557         setup_fb_info(msmfb);
 558
 559         spin_lock_init(&msmfb->update_lock);
 560         mutex_init(&msmfb->panel_init_lock);
 561         init_waitqueue_head(&msmfb->frame_wq);
 562         msmfb->resume_workqueue = create_workqueue("panel_on");
 563         if (msmfb->resume_workqueue == NULL) {
 564                 printk(KERN_ERR "failed to create panel_on workqueue\n");
 565                 ret = -ENOMEM;
 566                 goto error_create_workqueue;
 567         }
 568         INIT_WORK(&msmfb->resume_work, power_on_panel);
 569         msmfb->black = kzalloc(msmfb->fb->var.bits_per_pixel*msmfb->xres,
 570                                GFP_KERNEL);
 571
 572         printk(KERN_INFO "msmfb_probe() installing %d x %d panel\n",
 573                msmfb->xres, msmfb->yres);
 574
 575         msmfb->dma_callback.func = msmfb_handle_dma_interrupt;
 576         msmfb->vsync_callback.func = msmfb_handle_vsync_interrupt;
 577         hrtimer_init(&msmfb->fake_vsync, CLOCK_MONOTONIC,
 578                      HRTIMER_MODE_REL);
 579
 580
 581         msmfb->fake_vsync.function = msmfb_fake_vsync;
 582
 583         ret = register_framebuffer(fb);
 584         if (ret)
 585                 goto error_register_framebuffer;
 586
 587         msmfb->sleeping = WAKING;
 588
 589         return 0;
 590
 591 error_register_framebuffer:
 592         destroy_workqueue(msmfb->resume_workqueue);
 593 error_create_workqueue:
 594         iounmap(fb->screen_base);
 595 error_setup_fbmem:
 596         framebuffer_release(msmfb->fb);
 597         return ret;
 598 }
 599
 600 static struct platform_driver msm_panel_driver = {
 601         /* need to write remove */
 602         .probe = msmfb_probe,
 603         .driver = {.name = "msm_panel"},
 604 };
 605
 606
 607 static int msmfb_add_mdp_device(struct device *dev,
 608                                 struct class_interface *class_intf)
 609 {
 610         /* might need locking if mulitple mdp devices */
 611         if (mdp)
 612                 return 0;
 613         mdp = container_of(dev, struct mdp_device, dev);
 614         return platform_driver_register(&msm_panel_driver);
 615 }
 616
 617 static void msmfb_remove_mdp_device(struct device *dev,
 618                                 struct class_interface *class_intf)
 619 {
 620         /* might need locking if mulitple mdp devices */
 621         if (dev != &mdp->dev)
 622                 return;
 623         platform_driver_unregister(&msm_panel_driver);
 624         mdp = NULL;
 625 }
 626
 627 static struct class_interface msm_fb_interface = {
 628         .add_dev = &msmfb_add_mdp_device,
 629         .remove_dev = &msmfb_remove_mdp_device,
 630 };
 631
 632 static int __init msmfb_init(void)
 633 {
 634         return register_mdp_client(&msm_fb_interface);
 635 }
 636
 637 module_init(msmfb_init);