for (f = 0; f < 4; f++) {
                        prepare_to_wait(&itv->vsync_waitq, &wait,
                                        TASK_UNINTERRUPTIBLE);
-                       if ((read_reg(0x28c0) >> 16) < 100)
+                       if ((read_reg(IVTV_REG_DEC_LINE_FIELD) >> 16) < 100)
                                break;
                        schedule_timeout(msecs_to_jiffies(25));
                }
 
         * to determine the line being displayed and ensure we handle
         * one vsync per frame.
         */
-       unsigned int frame = read_reg(0x28c0) & 1;
+       unsigned int frame = read_reg(IVTV_REG_DEC_LINE_FIELD) & 1;
        struct yuv_playback_info *yi = &itv->yuv_info;
        int last_dma_frame = atomic_read(&yi->next_dma_frame);
        struct yuv_frame_info *f = &yi->new_frame_info[last_dma_frame];
                 */
                if (~itv->irqmask & IVTV_IRQ_DEC_VSYNC) {
                        /* vsync is enabled, see if we're in a new field */
-                       if ((itv->last_vsync_field & 1) != (read_reg(0x28c0) & 1)) {
+                       if ((itv->last_vsync_field & 1) !=
+                           (read_reg(IVTV_REG_DEC_LINE_FIELD) & 1)) {
                                /* New field, looks like we missed it */
-                               IVTV_DEBUG_YUV("VSync interrupt missed %d\n",read_reg(0x28c0)>>16);
+                               IVTV_DEBUG_YUV("VSync interrupt missed %d\n",
+                                      read_reg(IVTV_REG_DEC_LINE_FIELD) >> 16);
                                vsync_force = 1;
                        }
                }
 
 
                        vblank.flags = FB_VBLANK_HAVE_COUNT |FB_VBLANK_HAVE_VCOUNT |
                                        FB_VBLANK_HAVE_VSYNC;
-                       trace = read_reg(0x028c0) >> 16;
+                       trace = read_reg(IVTV_REG_DEC_LINE_FIELD) >> 16;
                        if (itv->is_50hz && trace > 312)
                                trace -= 312;
                        else if (itv->is_60hz && trace > 262)