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 work_struct resume_work;
  85         struct msmfb_callback dma_callback;
  86         struct msmfb_callback vsync_callback;
  87         struct hrtimer fake_vsync;
  88         ktime_t vsync_request_time;
  89 };
  90
  91 static int msmfb_open(struct fb_info *info, int user)
  92 {
  93         return 0;
  94 }
  95
  96 static int msmfb_release(struct fb_info *info, int user)
  97 {
  98         return 0;
  99 }
 100
 101 /* Called from dma interrupt handler, must not sleep */
 102 static void msmfb_handle_dma_interrupt(struct msmfb_callback *callback)
 103 {
 104         unsigned long irq_flags;
 105         struct msmfb_info *msmfb  = container_of(callback, struct msmfb_info,
 106                                                dma_callback);
 107
 108         spin_lock_irqsave(&msmfb->update_lock, irq_flags);
 109         msmfb->frame_done = msmfb->frame_requested;
 110         if (msmfb->sleeping == UPDATING &&
 111             msmfb->frame_done == msmfb->update_frame) {
 112                 DLOG(SUSPEND_RESUME, "full update completed\n");
 113                 schedule_work(&msmfb->resume_work);
 114         }
 115         spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 116         wake_up(&msmfb->frame_wq);
 117 }
 118
 119 static int msmfb_start_dma(struct msmfb_info *msmfb)
 120 {
 121         uint32_t x, y, w, h;
 122         unsigned addr;
 123         unsigned long irq_flags;
 124         uint32_t yoffset;
 125         s64 time_since_request;
 126         struct msm_panel_data *panel = msmfb->panel;
 127
 128         spin_lock_irqsave(&msmfb->update_lock, irq_flags);
 129         time_since_request = ktime_to_ns(ktime_sub(ktime_get(),
 130                              msmfb->vsync_request_time));
 131         if (time_since_request > 20 * NSEC_PER_MSEC) {
 132                 uint32_t us;
 133                 us = do_div(time_since_request, NSEC_PER_MSEC) / NSEC_PER_USEC;
 134                 printk(KERN_WARNING "msmfb_start_dma %lld.%03u ms after vsync "
 135                         "request\n", time_since_request, us);
 136         }
 137         if (msmfb->frame_done == msmfb->frame_requested) {
 138                 spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 139                 return -1;
 140         }
 141         if (msmfb->sleeping == SLEEPING) {
 142                 DLOG(SUSPEND_RESUME, "tried to start dma while asleep\n");
 143                 spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 144                 return -1;
 145         }
 146         x = msmfb->update_info.left;
 147         y = msmfb->update_info.top;
 148         w = msmfb->update_info.eright - x;
 149         h = msmfb->update_info.ebottom - y;
 150         yoffset = msmfb->yoffset;
 151         msmfb->update_info.left = msmfb->xres + 1;
 152         msmfb->update_info.top = msmfb->yres + 1;
 153         msmfb->update_info.eright = 0;
 154         msmfb->update_info.ebottom = 0;
 155         if (unlikely(w > msmfb->xres || h > msmfb->yres ||
 156                      w == 0 || h == 0)) {
 157                 printk(KERN_INFO "invalid update: %d %d %d "
 158                                 "%d\n", x, y, w, h);
 159                 msmfb->frame_done = msmfb->frame_requested;
 160                 goto error;
 161         }
 162         spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 163
 164         addr = ((msmfb->xres * (yoffset + y) + x) * 2);
 165         mdp->dma(mdp, addr + msmfb->fb->fix.smem_start,
 166                  msmfb->xres * 2, w, h, x, y, &msmfb->dma_callback,
 167                  panel->interface_type);
 168         return 0;
 169 error:
 170         spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 171         /* some clients need to clear their vsync interrupt */
 172         if (panel->clear_vsync)
 173                 panel->clear_vsync(panel);
 174         wake_up(&msmfb->frame_wq);
 175         return 0;
 176 }
 177
 178 /* Called from esync interrupt handler, must not sleep */
 179 static void msmfb_handle_vsync_interrupt(struct msmfb_callback *callback)
 180 {
 181         struct msmfb_info *msmfb = container_of(callback, struct msmfb_info,
 182                                                vsync_callback);
 183         msmfb_start_dma(msmfb);
 184 }
 185
 186 static enum hrtimer_restart msmfb_fake_vsync(struct hrtimer *timer)
 187 {
 188         struct msmfb_info *msmfb  = container_of(timer, struct msmfb_info,
 189                                                fake_vsync);
 190         msmfb_start_dma(msmfb);
 191         return HRTIMER_NORESTART;
 192 }
 193
 194 static void msmfb_pan_update(struct fb_info *info, uint32_t left, uint32_t top,
 195                              uint32_t eright, uint32_t ebottom,
 196                              uint32_t yoffset, int pan_display)
 197 {
 198         struct msmfb_info *msmfb = info->par;
 199         struct msm_panel_data *panel = msmfb->panel;
 200         unsigned long irq_flags;
 201         int sleeping;
 202         int retry = 1;
 203
 204         DLOG(SHOW_UPDATES, "update %d %d %d %d %d %d\n",
 205                 left, top, eright, ebottom, yoffset, pan_display);
 206 restart:
 207         spin_lock_irqsave(&msmfb->update_lock, irq_flags);
 208
 209         /* if we are sleeping, on a pan_display wait 10ms (to throttle back
 210          * drawing otherwise return */
 211         if (msmfb->sleeping == SLEEPING) {
 212                 DLOG(SUSPEND_RESUME, "drawing while asleep\n");
 213                 spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 214                 if (pan_display)
 215                         wait_event_interruptible_timeout(msmfb->frame_wq,
 216                                 msmfb->sleeping != SLEEPING, HZ/10);
 217                 return;
 218         }
 219
 220         sleeping = msmfb->sleeping;
 221         /* on a full update, if the last frame has not completed, wait for it */
 222         if ((pan_display && msmfb->frame_requested != msmfb->frame_done) ||
 223                             sleeping == UPDATING) {
 224                 int ret;
 225                 spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 226                 ret = wait_event_interruptible_timeout(msmfb->frame_wq,
 227                         msmfb->frame_done == msmfb->frame_requested &&
 228                         msmfb->sleeping != UPDATING, 5 * HZ);
 229                 if (ret <= 0 && (msmfb->frame_requested != msmfb->frame_done ||
 230                                  msmfb->sleeping == UPDATING)) {
 231                         if (retry && panel->request_vsync &&
 232                             (sleeping == AWAKE)) {
 233                                 panel->request_vsync(panel,
 234                                         &msmfb->vsync_callback);
 235                                 retry = 0;
 236                                 printk(KERN_WARNING "msmfb_pan_display timeout "
 237                                         "rerequest vsync\n");
 238                         } else {
 239                                 printk(KERN_WARNING "msmfb_pan_display timeout "
 240                                         "waiting for frame start, %d %d\n",
 241                                         msmfb->frame_requested,
 242                                         msmfb->frame_done);
 243                                 return;
 244                         }
 245                 }
 246                 goto restart;
 247         }
 248
 249
 250         msmfb->frame_requested++;
 251         /* if necessary, update the y offset, if this is the
 252          * first full update on resume, set the sleeping state */
 253         if (pan_display) {
 254                 msmfb->yoffset = yoffset;
 255                 if (left == 0 && top == 0 && eright == info->var.xres &&
 256                     ebottom == info->var.yres) {
 257                         if (sleeping == WAKING) {
 258                                 msmfb->update_frame = msmfb->frame_requested;
 259                                 DLOG(SUSPEND_RESUME, "full update starting\n");
 260                                 msmfb->sleeping = UPDATING;
 261                         }
 262                 }
 263         }
 264
 265         /* set the update request */
 266         if (left < msmfb->update_info.left)
 267                 msmfb->update_info.left = left;
 268         if (top < msmfb->update_info.top)
 269                 msmfb->update_info.top = top;
 270         if (eright > msmfb->update_info.eright)
 271                 msmfb->update_info.eright = eright;
 272         if (ebottom > msmfb->update_info.ebottom)
 273                 msmfb->update_info.ebottom = ebottom;
 274         DLOG(SHOW_UPDATES, "update queued %d %d %d %d %d\n",
 275                 msmfb->update_info.left, msmfb->update_info.top,
 276                 msmfb->update_info.eright, msmfb->update_info.ebottom,
 277                 msmfb->yoffset);
 278         spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 279
 280         /* if the panel is all the way on wait for vsync, otherwise sleep
 281          * for 16 ms (long enough for the dma to panel) and then begin dma */
 282         msmfb->vsync_request_time = ktime_get();
 283         if (panel->request_vsync && (sleeping == AWAKE)) {
 284                 panel->request_vsync(panel, &msmfb->vsync_callback);
 285         } else {
 286                 if (!hrtimer_active(&msmfb->fake_vsync)) {
 287                         hrtimer_start(&msmfb->fake_vsync,
 288                                       ktime_set(0, NSEC_PER_SEC/60),
 289                                       HRTIMER_MODE_REL);
 290                 }
 291         }
 292 }
 293
 294 static void msmfb_update(struct fb_info *info, uint32_t left, uint32_t top,
 295                          uint32_t eright, uint32_t ebottom)
 296 {
 297         msmfb_pan_update(info, left, top, eright, ebottom, 0, 0);
 298 }
 299
 300 static void power_on_panel(struct work_struct *work)
 301 {
 302         struct msmfb_info *msmfb =
 303                 container_of(work, struct msmfb_info, resume_work);
 304         struct msm_panel_data *panel = msmfb->panel;
 305         unsigned long irq_flags;
 306
 307         mutex_lock(&msmfb->panel_init_lock);
 308         DLOG(SUSPEND_RESUME, "turning on panel\n");
 309         if (msmfb->sleeping == UPDATING) {
 310                 if (panel->unblank(panel)) {
 311                         printk(KERN_INFO "msmfb: panel unblank failed,"
 312                                "not starting drawing\n");
 313                         goto error;
 314                 }
 315                 spin_lock_irqsave(&msmfb->update_lock, irq_flags);
 316                 msmfb->sleeping = AWAKE;
 317                 wake_up(&msmfb->frame_wq);
 318                 spin_unlock_irqrestore(&msmfb->update_lock, irq_flags);
 319         }
 320 error:
 321         mutex_unlock(&msmfb->panel_init_lock);
 322 }
 323
 324
 325 static int msmfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
 326 {
 327         if ((var->xres != info->var.xres) ||
 328             (var->yres != info->var.yres) ||
 329             (var->xres_virtual != info->var.xres_virtual) ||
 330             (var->yres_virtual != info->var.yres_virtual) ||
 331             (var->xoffset != info->var.xoffset) ||
 332             (var->bits_per_pixel != info->var.bits_per_pixel) ||
 333             (var->grayscale != info->var.grayscale))
 334                  return -EINVAL;
 335         return 0;
 336 }
 337
 338 int msmfb_pan_display(struct fb_var_screeninfo *var, struct fb_info *info)
 339 {
 340         struct msmfb_info *msmfb = info->par;
 341         struct msm_panel_data *panel = msmfb->panel;
 342
 343         /* "UPDT" */
 344         if ((panel->caps & MSMFB_CAP_PARTIAL_UPDATES) &&
 345             (var->reserved[0] == 0x54445055)) {
 346                 msmfb_pan_update(info, var->reserved[1] & 0xffff,
 347                                  var->reserved[1] >> 16,
 348                                  var->reserved[2] & 0xffff,
 349                                  var->reserved[2] >> 16, var->yoffset, 1);
 350         } else {
 351                 msmfb_pan_update(info, 0, 0, info->var.xres, info->var.yres,
 352                                  var->yoffset, 1);
 353         }
 354         return 0;
 355 }
 356
 357 static void msmfb_fillrect(struct fb_info *p, const struct fb_fillrect *rect)
 358 {
 359         cfb_fillrect(p, rect);
 360         msmfb_update(p, rect->dx, rect->dy, rect->dx + rect->width,
 361                      rect->dy + rect->height);
 362 }
 363
 364 static void msmfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
 365 {
 366         cfb_copyarea(p, area);
 367         msmfb_update(p, area->dx, area->dy, area->dx + area->width,
 368                      area->dy + area->height);
 369 }
 370
 371 static void msmfb_imageblit(struct fb_info *p, const struct fb_image *image)
 372 {
 373         cfb_imageblit(p, image);
 374         msmfb_update(p, image->dx, image->dy, image->dx + image->width,
 375                      image->dy + image->height);
 376 }
 377
 378
 379 static int msmfb_blit(struct fb_info *info,
 380                       void __user *p)
 381 {
 382         struct mdp_blit_req req;
 383         struct mdp_blit_req_list req_list;
 384         int i;
 385         int ret;
 386
 387         if (copy_from_user(&req_list, p, sizeof(req_list)))
 388                 return -EFAULT;
 389
 390         for (i = 0; i < req_list.count; i++) {
 391                 struct mdp_blit_req_list *list =
 392                         (struct mdp_blit_req_list *)p;
 393                 if (copy_from_user(&req, &list->req[i], sizeof(req)))
 394                         return -EFAULT;
 395                 ret = mdp->blit(mdp, info, &req);
 396                 if (ret)
 397                         return ret;
 398         }
 399         return 0;
 400 }
 401
 402
 403 DEFINE_MUTEX(mdp_ppp_lock);
 404
 405 static int msmfb_ioctl(struct fb_info *p, unsigned int cmd, unsigned long arg)
 406 {
 407         void __user *argp = (void __user *)arg;
 408         int ret;
 409
 410         switch (cmd) {
 411         case MSMFB_GRP_DISP:
 412                 mdp->set_grp_disp(mdp, arg);
 413                 break;
 414         case MSMFB_BLIT:
 415                 ret = msmfb_blit(p, argp);
 416                 if (ret)
 417                         return ret;
 418                 break;
 419         default:
 420                         printk(KERN_INFO "msmfb unknown ioctl: %d\n", cmd);
 421                         return -EINVAL;
 422         }
 423         return 0;
 424 }
 425
 426 static struct fb_ops msmfb_ops = {
 427         .owner = THIS_MODULE,
 428         .fb_open = msmfb_open,
 429         .fb_release = msmfb_release,
 430         .fb_check_var = msmfb_check_var,
 431         .fb_pan_display = msmfb_pan_display,
 432         .fb_fillrect = msmfb_fillrect,
 433         .fb_copyarea = msmfb_copyarea,
 434         .fb_imageblit = msmfb_imageblit,
 435         .fb_ioctl = msmfb_ioctl,
 436 };
 437
 438 static unsigned PP[16];
 439
 440
 441
 442 #define BITS_PER_PIXEL 16
 443
 444 static void setup_fb_info(struct msmfb_info *msmfb)
 445 {
 446         struct fb_info *fb_info = msmfb->fb;
 447         int r;
 448
 449         /* finish setting up the fb_info struct */
 450         strncpy(fb_info->fix.id, "msmfb", 16);
 451         fb_info->fix.ypanstep = 1;
 452
 453         fb_info->fbops = &msmfb_ops;
 454         fb_info->flags = FBINFO_DEFAULT;
 455
 456         fb_info->fix.type = FB_TYPE_PACKED_PIXELS;
 457         fb_info->fix.visual = FB_VISUAL_TRUECOLOR;
 458         fb_info->fix.line_length = msmfb->xres * 2;
 459
 460         fb_info->var.xres = msmfb->xres;
 461         fb_info->var.yres = msmfb->yres;
 462         fb_info->var.width = msmfb->panel->fb_data->width;
 463         fb_info->var.height = msmfb->panel->fb_data->height;
 464         fb_info->var.xres_virtual = msmfb->xres;
 465         fb_info->var.yres_virtual = msmfb->yres * 2;
 466         fb_info->var.bits_per_pixel = BITS_PER_PIXEL;
 467         fb_info->var.accel_flags = 0;
 468
 469         fb_info->var.yoffset = 0;
 470
 471         if (msmfb->panel->caps & MSMFB_CAP_PARTIAL_UPDATES) {
 472                 /*
 473                  * Set the param in the fixed screen, so userspace can't
 474                  * change it. This will be used to check for the
 475                  * capability.
 476                  */
 477                 fb_info->fix.reserved[0] = 0x5444;
 478                 fb_info->fix.reserved[1] = 0x5055;
 479
 480                 /*
 481                  * This preloads the value so that if userspace doesn't
 482                  * change it, it will be a full update
 483                  */
 484                 fb_info->var.reserved[0] = 0x54445055;
 485                 fb_info->var.reserved[1] = 0;
 486                 fb_info->var.reserved[2] = (uint16_t)msmfb->xres |
 487                                            ((uint32_t)msmfb->yres << 16);
 488         }
 489
 490         fb_info->var.red.offset = 11;
 491         fb_info->var.red.length = 5;
 492         fb_info->var.red.msb_right = 0;
 493         fb_info->var.green.offset = 5;
 494         fb_info->var.green.length = 6;
 495         fb_info->var.green.msb_right = 0;
 496         fb_info->var.blue.offset = 0;
 497         fb_info->var.blue.length = 5;
 498         fb_info->var.blue.msb_right = 0;
 499
 500         r = fb_alloc_cmap(&fb_info->cmap, 16, 0);
 501         fb_info->pseudo_palette = PP;
 502
 503         PP[0] = 0;
 504         for (r = 1; r < 16; r++)
 505                 PP[r] = 0xffffffff;
 506 }
 507
 508 static int setup_fbmem(struct msmfb_info *msmfb, struct platform_device *pdev)
 509 {
 510         struct fb_info *fb = msmfb->fb;
 511         struct resource *resource;
 512         unsigned long size = msmfb->xres * msmfb->yres *
 513                              (BITS_PER_PIXEL >> 3) * 2;
 514         unsigned char *fbram;
 515
 516         /* board file might have attached a resource describing an fb */
 517         resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 518         if (!resource)
 519                 return -EINVAL;
 520
 521         /* check the resource is large enough to fit the fb */
 522         if (resource->end - resource->start < size) {
 523                 printk(KERN_ERR "allocated resource is too small for "
 524                                 "fb\n");
 525                 return -ENOMEM;
 526         }
 527         fb->fix.smem_start = resource->start;
 528         fb->fix.smem_len = resource_size(resource);
 529         fbram = ioremap(resource->start, resource_size(resource));
 530         if (fbram == NULL) {
 531                 printk(KERN_ERR "msmfb: cannot allocate fbram!\n");
 532                 return -ENOMEM;
 533         }
 534         fb->screen_base = fbram;
 535         return 0;
 536 }
 537
 538 static int msmfb_probe(struct platform_device *pdev)
 539 {
 540         struct fb_info *fb;
 541         struct msmfb_info *msmfb;
 542         struct msm_panel_data *panel = pdev->dev.platform_data;
 543         int ret;
 544
 545         if (!panel) {
 546                 pr_err("msmfb_probe: no platform data\n");
 547                 return -EINVAL;
 548         }
 549         if (!panel->fb_data) {
 550                 pr_err("msmfb_probe: no fb_data\n");
 551                 return -EINVAL;
 552         }
 553
 554         fb = framebuffer_alloc(sizeof(struct msmfb_info), &pdev->dev);
 555         if (!fb)
 556                 return -ENOMEM;
 557         msmfb = fb->par;
 558         msmfb->fb = fb;
 559         msmfb->panel = panel;
 560         msmfb->xres = panel->fb_data->xres;
 561         msmfb->yres = panel->fb_data->yres;
 562
 563         ret = setup_fbmem(msmfb, pdev);
 564         if (ret)
 565                 goto error_setup_fbmem;
 566
 567         setup_fb_info(msmfb);
 568
 569         spin_lock_init(&msmfb->update_lock);
 570         mutex_init(&msmfb->panel_init_lock);
 571         init_waitqueue_head(&msmfb->frame_wq);
 572         INIT_WORK(&msmfb->resume_work, power_on_panel);
 573         msmfb->black = kzalloc(msmfb->fb->var.bits_per_pixel*msmfb->xres,
 574                                GFP_KERNEL);
 575
 576         printk(KERN_INFO "msmfb_probe() installing %d x %d panel\n",
 577                msmfb->xres, msmfb->yres);
 578
 579         msmfb->dma_callback.func = msmfb_handle_dma_interrupt;
 580         msmfb->vsync_callback.func = msmfb_handle_vsync_interrupt;
 581         hrtimer_init(&msmfb->fake_vsync, CLOCK_MONOTONIC,
 582                      HRTIMER_MODE_REL);
 583
 584
 585         msmfb->fake_vsync.function = msmfb_fake_vsync;
 586
 587         ret = register_framebuffer(fb);
 588         if (ret)
 589                 goto error_register_framebuffer;
 590
 591         msmfb->sleeping = WAKING;
 592
 593         return 0;
 594
 595 error_register_framebuffer:
 596         iounmap(fb->screen_base);
 597 error_setup_fbmem:
 598         framebuffer_release(msmfb->fb);
 599         return ret;
 600 }
 601
 602 static struct platform_driver msm_panel_driver = {
 603         /* need to write remove */
 604         .probe = msmfb_probe,
 605         .driver = {.name = "msm_panel"},
 606 };
 607
 608
 609 static int msmfb_add_mdp_device(struct device *dev,
 610                                 struct class_interface *class_intf)
 611 {
 612         /* might need locking if mulitple mdp devices */
 613         if (mdp)
 614                 return 0;
 615         mdp = container_of(dev, struct mdp_device, dev);
 616         return platform_driver_register(&msm_panel_driver);
 617 }
 618
 619 static void msmfb_remove_mdp_device(struct device *dev,
 620                                 struct class_interface *class_intf)
 621 {
 622         /* might need locking if mulitple mdp devices */
 623         if (dev != &mdp->dev)
 624                 return;
 625         platform_driver_unregister(&msm_panel_driver);
 626         mdp = NULL;
 627 }
 628
 629 static struct class_interface msm_fb_interface = {
 630         .add_dev = &msmfb_add_mdp_device,
 631         .remove_dev = &msmfb_remove_mdp_device,
 632 };
 633
 634 static int __init msmfb_init(void)
 635 {
 636         return register_mdp_client(&msm_fb_interface);
 637 }
 638
 639 module_init(msmfb_init);