drivers/video/via/dvi.c

   1 /*
   2  * Copyright 1998-2008 VIA Technologies, Inc. All Rights Reserved.
   3  * Copyright 2001-2008 S3 Graphics, Inc. All Rights Reserved.
   4
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public
   7  * License as published by the Free Software Foundation;
   8  * either version 2, or (at your option) any later version.
   9
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTIES OR REPRESENTATIONS; without even
  12  * the implied warranty of MERCHANTABILITY or FITNESS FOR
  13  * A PARTICULAR PURPOSE.See the GNU General Public License
  14  * for more details.
  15
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc.,
  19  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  20  */
  21 #include <linux/via-core.h>
  22 #include <linux/via_i2c.h>
  23 #include "global.h"
  24
  25 static void tmds_register_write(int index, u8 data);
  26 static int tmds_register_read(int index);
  27 static int tmds_register_read_bytes(int index, u8 *buff, int buff_len);
  28 static void __devinit dvi_get_panel_size_from_DDCv1(
  29         struct tmds_chip_information *tmds_chip,
  30         struct tmds_setting_information *tmds_setting);
  31 static void __devinit dvi_get_panel_size_from_DDCv2(
  32         struct tmds_chip_information *tmds_chip,
  33         struct tmds_setting_information *tmds_setting);
  34 static int viafb_dvi_query_EDID(void);
  35
  36 static int check_tmds_chip(int device_id_subaddr, int device_id)
  37 {
  38         if (tmds_register_read(device_id_subaddr) == device_id)
  39                 return OK;
  40         else
  41                 return FAIL;
  42 }
  43
  44 void __devinit viafb_init_dvi_size(struct tmds_chip_information *tmds_chip,
  45         struct tmds_setting_information *tmds_setting)
  46 {
  47         DEBUG_MSG(KERN_INFO "viafb_init_dvi_size()\n");
  48
  49         viafb_dvi_sense();
  50         switch (viafb_dvi_query_EDID()) {
  51         case 1:
  52                 dvi_get_panel_size_from_DDCv1(tmds_chip, tmds_setting);
  53                 break;
  54         case 2:
  55                 dvi_get_panel_size_from_DDCv2(tmds_chip, tmds_setting);
  56                 break;
  57         default:
  58                 printk(KERN_WARNING "viafb_init_dvi_size: DVI panel size undetected!\n");
  59                 break;
  60         }
  61
  62         return;
  63 }
  64
  65 int __devinit viafb_tmds_trasmitter_identify(void)
  66 {
  67         unsigned char sr2a = 0, sr1e = 0, sr3e = 0;
  68
  69         /* Turn on ouputting pad */
  70         switch (viaparinfo->chip_info->gfx_chip_name) {
  71         case UNICHROME_K8M890:
  72             /*=* DFP Low Pad on *=*/
  73                 sr2a = viafb_read_reg(VIASR, SR2A);
  74                 viafb_write_reg_mask(SR2A, VIASR, 0x03, BIT0 + BIT1);
  75                 break;
  76
  77         case UNICHROME_P4M900:
  78         case UNICHROME_P4M890:
  79                 /* DFP Low Pad on */
  80                 sr2a = viafb_read_reg(VIASR, SR2A);
  81                 viafb_write_reg_mask(SR2A, VIASR, 0x03, BIT0 + BIT1);
  82                 /* DVP0 Pad on */
  83                 sr1e = viafb_read_reg(VIASR, SR1E);
  84                 viafb_write_reg_mask(SR1E, VIASR, 0xC0, BIT6 + BIT7);
  85                 break;
  86
  87         default:
  88             /* DVP0/DVP1 Pad on */
  89                 sr1e = viafb_read_reg(VIASR, SR1E);
  90                 viafb_write_reg_mask(SR1E, VIASR, 0xF0, BIT4 +
  91                         BIT5 + BIT6 + BIT7);
  92             /* SR3E[1]Multi-function selection:
  93             0 = Emulate I2C and DDC bus by GPIO2/3/4. */
  94                 sr3e = viafb_read_reg(VIASR, SR3E);
  95                 viafb_write_reg_mask(SR3E, VIASR, 0x0, BIT5);
  96                 break;
  97         }
  98
  99         /* Check for VT1632: */
 100         viaparinfo->chip_info->tmds_chip_info.tmds_chip_name = VT1632_TMDS;
 101         viaparinfo->chip_info->
 102                 tmds_chip_info.tmds_chip_slave_addr = VT1632_TMDS_I2C_ADDR;
 103         viaparinfo->chip_info->tmds_chip_info.i2c_port = VIA_PORT_31;
 104         if (check_tmds_chip(VT1632_DEVICE_ID_REG, VT1632_DEVICE_ID) != FAIL) {
 105                 /*
 106                  * Currently only support 12bits,dual edge,add 24bits mode later
 107                  */
 108                 tmds_register_write(0x08, 0x3b);
 109
 110                 DEBUG_MSG(KERN_INFO "\n VT1632 TMDS ! \n");
 111                 DEBUG_MSG(KERN_INFO "\n %2d",
 112                           viaparinfo->chip_info->tmds_chip_info.tmds_chip_name);
 113                 DEBUG_MSG(KERN_INFO "\n %2d",
 114                           viaparinfo->chip_info->tmds_chip_info.i2c_port);
 115                 return OK;
 116         } else {
 117                 viaparinfo->chip_info->tmds_chip_info.i2c_port = VIA_PORT_2C;
 118                 if (check_tmds_chip(VT1632_DEVICE_ID_REG, VT1632_DEVICE_ID)
 119                     != FAIL) {
 120                         tmds_register_write(0x08, 0x3b);
 121                         DEBUG_MSG(KERN_INFO "\n VT1632 TMDS ! \n");
 122                         DEBUG_MSG(KERN_INFO "\n %2d",
 123                                   viaparinfo->chip_info->
 124                                   tmds_chip_info.tmds_chip_name);
 125                         DEBUG_MSG(KERN_INFO "\n %2d",
 126                                   viaparinfo->chip_info->
 127                                   tmds_chip_info.i2c_port);
 128                         return OK;
 129                 }
 130         }
 131
 132         viaparinfo->chip_info->tmds_chip_info.tmds_chip_name = INTEGRATED_TMDS;
 133
 134         if ((viaparinfo->chip_info->gfx_chip_name == UNICHROME_CX700) &&
 135             ((viafb_display_hardware_layout == HW_LAYOUT_DVI_ONLY) ||
 136              (viafb_display_hardware_layout == HW_LAYOUT_LCD_DVI))) {
 137                 DEBUG_MSG(KERN_INFO "\n Integrated TMDS ! \n");
 138                 return OK;
 139         }
 140
 141         switch (viaparinfo->chip_info->gfx_chip_name) {
 142         case UNICHROME_K8M890:
 143                 viafb_write_reg(SR2A, VIASR, sr2a);
 144                 break;
 145
 146         case UNICHROME_P4M900:
 147         case UNICHROME_P4M890:
 148                 viafb_write_reg(SR2A, VIASR, sr2a);
 149                 viafb_write_reg(SR1E, VIASR, sr1e);
 150                 break;
 151
 152         default:
 153                 viafb_write_reg(SR1E, VIASR, sr1e);
 154                 viafb_write_reg(SR3E, VIASR, sr3e);
 155                 break;
 156         }
 157
 158         viaparinfo->chip_info->
 159                 tmds_chip_info.tmds_chip_name = NON_TMDS_TRANSMITTER;
 160         viaparinfo->chip_info->tmds_chip_info.
 161                 tmds_chip_slave_addr = VT1632_TMDS_I2C_ADDR;
 162         return FAIL;
 163 }
 164
 165 static void tmds_register_write(int index, u8 data)
 166 {
 167         viafb_i2c_writebyte(viaparinfo->chip_info->tmds_chip_info.i2c_port,
 168                             viaparinfo->chip_info->tmds_chip_info.tmds_chip_slave_addr,
 169                             index, data);
 170 }
 171
 172 static int tmds_register_read(int index)
 173 {
 174         u8 data;
 175
 176         viafb_i2c_readbyte(viaparinfo->chip_info->tmds_chip_info.i2c_port,
 177                            (u8) viaparinfo->chip_info->tmds_chip_info.tmds_chip_slave_addr,
 178                            (u8) index, &data);
 179         return data;
 180 }
 181
 182 static int tmds_register_read_bytes(int index, u8 *buff, int buff_len)
 183 {
 184         viafb_i2c_readbytes(viaparinfo->chip_info->tmds_chip_info.i2c_port,
 185                             (u8) viaparinfo->chip_info->tmds_chip_info.tmds_chip_slave_addr,
 186                             (u8) index, buff, buff_len);
 187         return 0;
 188 }
 189
 190 /* DVI Set Mode */
 191 void viafb_dvi_set_mode(struct VideoModeTable *mode, int mode_bpp,
 192         int set_iga)
 193 {
 194         struct VideoModeTable *rb_mode;
 195         struct crt_mode_table *pDviTiming;
 196         unsigned long desirePixelClock, maxPixelClock;
 197         pDviTiming = mode->crtc;
 198         desirePixelClock = pDviTiming->refresh_rate
 199                 * pDviTiming->crtc.hor_total * pDviTiming->crtc.ver_total
 200                 / 1000000;
 201         maxPixelClock = (unsigned long)viaparinfo->
 202                 tmds_setting_info->max_pixel_clock;
 203
 204         DEBUG_MSG(KERN_INFO "\nDVI_set_mode!!\n");
 205
 206         if ((maxPixelClock != 0) && (desirePixelClock > maxPixelClock)) {
 207                 rb_mode = viafb_get_rb_mode(mode->crtc[0].crtc.hor_addr,
 208                         mode->crtc[0].crtc.ver_addr);
 209                 if (rb_mode) {
 210                         mode = rb_mode;
 211                         pDviTiming = rb_mode->crtc;
 212                 }
 213         }
 214         viafb_fill_crtc_timing(pDviTiming, mode, mode_bpp / 8, set_iga);
 215 }
 216
 217 /* Sense DVI Connector */
 218 int viafb_dvi_sense(void)
 219 {
 220         u8 RegSR1E = 0, RegSR3E = 0, RegCR6B = 0, RegCR91 = 0,
 221                 RegCR93 = 0, RegCR9B = 0, data;
 222         int ret = false;
 223
 224         DEBUG_MSG(KERN_INFO "viafb_dvi_sense!!\n");
 225
 226         if (viaparinfo->chip_info->gfx_chip_name == UNICHROME_CLE266) {
 227                 /* DI1 Pad on */
 228                 RegSR1E = viafb_read_reg(VIASR, SR1E);
 229                 viafb_write_reg(SR1E, VIASR, RegSR1E | 0x30);
 230
 231                 /* CR6B[0]VCK Input Selection: 1 = External clock. */
 232                 RegCR6B = viafb_read_reg(VIACR, CR6B);
 233                 viafb_write_reg(CR6B, VIACR, RegCR6B | 0x08);
 234
 235                 /* CR91[4] VDD On [3] Data On [2] VEE On [1] Back Light Off
 236                    [0] Software Control Power Sequence */
 237                 RegCR91 = viafb_read_reg(VIACR, CR91);
 238                 viafb_write_reg(CR91, VIACR, 0x1D);
 239
 240                 /* CR93[7] DI1 Data Source Selection: 1 = DSP2.
 241                    CR93[5] DI1 Clock Source: 1 = internal.
 242                    CR93[4] DI1 Clock Polarity.
 243                    CR93[3:1] DI1 Clock Adjust. CR93[0] DI1 enable */
 244                 RegCR93 = viafb_read_reg(VIACR, CR93);
 245                 viafb_write_reg(CR93, VIACR, 0x01);
 246         } else {
 247                 /* DVP0/DVP1 Pad on */
 248                 RegSR1E = viafb_read_reg(VIASR, SR1E);
 249                 viafb_write_reg(SR1E, VIASR, RegSR1E | 0xF0);
 250
 251                 /* SR3E[1]Multi-function selection:
 252                    0 = Emulate I2C and DDC bus by GPIO2/3/4. */
 253                 RegSR3E = viafb_read_reg(VIASR, SR3E);
 254                 viafb_write_reg(SR3E, VIASR, RegSR3E & (~0x20));
 255
 256                 /* CR91[4] VDD On [3] Data On [2] VEE On [1] Back Light Off
 257                    [0] Software Control Power Sequence */
 258                 RegCR91 = viafb_read_reg(VIACR, CR91);
 259                 viafb_write_reg(CR91, VIACR, 0x1D);
 260
 261                 /*CR9B[4] DVP1 Data Source Selection: 1 = From secondary
 262                 display.CR9B[2:0] DVP1 Clock Adjust */
 263                 RegCR9B = viafb_read_reg(VIACR, CR9B);
 264                 viafb_write_reg(CR9B, VIACR, 0x01);
 265         }
 266
 267         data = (u8) tmds_register_read(0x09);
 268         if (data & 0x04)
 269                 ret = true;
 270
 271         if (ret == false) {
 272                 if (viafb_dvi_query_EDID())
 273                         ret = true;
 274         }
 275
 276         /* Restore status */
 277         viafb_write_reg(SR1E, VIASR, RegSR1E);
 278         viafb_write_reg(CR91, VIACR, RegCR91);
 279         if (viaparinfo->chip_info->gfx_chip_name == UNICHROME_CLE266) {
 280                 viafb_write_reg(CR6B, VIACR, RegCR6B);
 281                 viafb_write_reg(CR93, VIACR, RegCR93);
 282         } else {
 283                 viafb_write_reg(SR3E, VIASR, RegSR3E);
 284                 viafb_write_reg(CR9B, VIACR, RegCR9B);
 285         }
 286
 287         return ret;
 288 }
 289
 290 /* Query Flat Panel's EDID Table Version Through DVI Connector */
 291 static int viafb_dvi_query_EDID(void)
 292 {
 293         u8 data0, data1;
 294         int restore;
 295
 296         DEBUG_MSG(KERN_INFO "viafb_dvi_query_EDID!!\n");
 297
 298         restore = viaparinfo->chip_info->tmds_chip_info.tmds_chip_slave_addr;
 299         viaparinfo->chip_info->tmds_chip_info.tmds_chip_slave_addr = 0xA0;
 300
 301         data0 = (u8) tmds_register_read(0x00);
 302         data1 = (u8) tmds_register_read(0x01);
 303         if ((data0 == 0) && (data1 == 0xFF)) {
 304                 viaparinfo->chip_info->
 305                         tmds_chip_info.tmds_chip_slave_addr = restore;
 306                 return EDID_VERSION_1;  /* Found EDID1 Table */
 307         }
 308
 309         data0 = (u8) tmds_register_read(0x00);
 310         viaparinfo->chip_info->tmds_chip_info.tmds_chip_slave_addr = restore;
 311         if (data0 == 0x20)
 312                 return EDID_VERSION_2;  /* Found EDID2 Table */
 313         else
 314                 return false;
 315 }
 316
 317 /* Get Panel Size Using EDID1 Table */
 318 static void __devinit dvi_get_panel_size_from_DDCv1(
 319         struct tmds_chip_information *tmds_chip,
 320         struct tmds_setting_information *tmds_setting)
 321 {
 322         int i, max_h = 0, tmp, restore;
 323         unsigned char rData;
 324         unsigned char EDID_DATA[18];
 325
 326         DEBUG_MSG(KERN_INFO "\n dvi_get_panel_size_from_DDCv1 \n");
 327
 328         restore = tmds_chip->tmds_chip_slave_addr;
 329         tmds_chip->tmds_chip_slave_addr = 0xA0;
 330
 331         rData = tmds_register_read(0x23);
 332         if (rData & 0x3C)
 333                 max_h = 640;
 334         if (rData & 0xC0)
 335                 max_h = 720;
 336         if (rData & 0x03)
 337                 max_h = 800;
 338
 339         rData = tmds_register_read(0x24);
 340         if (rData & 0xC0)
 341                 max_h = 800;
 342         if (rData & 0x1E)
 343                 max_h = 1024;
 344         if (rData & 0x01)
 345                 max_h = 1280;
 346
 347         for (i = 0x25; i < 0x6D; i++) {
 348                 switch (i) {
 349                 case 0x26:
 350                 case 0x28:
 351                 case 0x2A:
 352                 case 0x2C:
 353                 case 0x2E:
 354                 case 0x30:
 355                 case 0x32:
 356                 case 0x34:
 357                         rData = tmds_register_read(i);
 358                         if (rData == 1)
 359                                 break;
 360                         /* data = (data + 31) * 8 */
 361                         tmp = (rData + 31) << 3;
 362                         if (tmp > max_h)
 363                                 max_h = tmp;
 364                         break;
 365
 366                 case 0x36:
 367                 case 0x48:
 368                 case 0x5A:
 369                 case 0x6C:
 370                         tmds_register_read_bytes(i, EDID_DATA, 10);
 371                         if (!(EDID_DATA[0] || EDID_DATA[1])) {
 372                                 /* The first two byte must be zero. */
 373                                 if (EDID_DATA[3] == 0xFD) {
 374                                         /* To get max pixel clock. */
 375                                         tmds_setting->max_pixel_clock =
 376                                                 EDID_DATA[9] * 10;
 377                                 }
 378                         }
 379                         break;
 380
 381                 default:
 382                         break;
 383                 }
 384         }
 385
 386         tmds_setting->max_hres = max_h;
 387         switch (max_h) {
 388         case 640:
 389                 tmds_setting->max_vres = 480;
 390                 break;
 391         case 800:
 392                 tmds_setting->max_vres = 600;
 393                 break;
 394         case 1024:
 395                 tmds_setting->max_vres = 768;
 396                 break;
 397         case 1280:
 398                 tmds_setting->max_vres = 1024;
 399                 break;
 400         case 1400:
 401                 tmds_setting->max_vres = 1050;
 402                 break;
 403         case 1440:
 404                 tmds_setting->max_vres = 1050;
 405                 break;
 406         case 1600:
 407                 tmds_setting->max_vres = 1200;
 408                 break;
 409         case 1920:
 410                 tmds_setting->max_vres = 1080;
 411                 break;
 412         default:
 413                 DEBUG_MSG(KERN_INFO "Unknown panel size max resolution = %d ! "
 414                                          "set default panel size.\n", max_h);
 415                 break;
 416         }
 417
 418         DEBUG_MSG(KERN_INFO "DVI max pixelclock = %d\n",
 419                 tmds_setting->max_pixel_clock);
 420         tmds_chip->tmds_chip_slave_addr = restore;
 421 }
 422
 423 /* Get Panel Size Using EDID2 Table */
 424 static void __devinit dvi_get_panel_size_from_DDCv2(
 425         struct tmds_chip_information *tmds_chip,
 426         struct tmds_setting_information *tmds_setting)
 427 {
 428         int restore;
 429         unsigned char R_Buffer[2];
 430
 431         DEBUG_MSG(KERN_INFO "\n dvi_get_panel_size_from_DDCv2 \n");
 432
 433         restore = tmds_chip->tmds_chip_slave_addr;
 434         tmds_chip->tmds_chip_slave_addr = 0xA2;
 435
 436         /* Horizontal: 0x76, 0x77 */
 437         tmds_register_read_bytes(0x76, R_Buffer, 2);
 438         tmds_setting->max_hres = R_Buffer[0] + (R_Buffer[1] << 8);
 439
 440         switch (tmds_setting->max_hres) {
 441         case 640:
 442                 tmds_setting->max_vres = 480;
 443                 break;
 444         case 800:
 445                 tmds_setting->max_vres = 600;
 446                 break;
 447         case 1024:
 448                 tmds_setting->max_vres = 768;
 449                 break;
 450         case 1280:
 451                 tmds_setting->max_vres = 1024;
 452                 break;
 453         case 1400:
 454                 tmds_setting->max_vres = 1050;
 455                 break;
 456         case 1440:
 457                 tmds_setting->max_vres = 1050;
 458                 break;
 459         case 1600:
 460                 tmds_setting->max_vres = 1200;
 461                 break;
 462         default:
 463                 DEBUG_MSG(KERN_INFO "Unknown panel size max resolution = %d! "
 464                         "set default panel size.\n", tmds_setting->max_hres);
 465                 break;
 466         }
 467
 468         tmds_chip->tmds_chip_slave_addr = restore;
 469 }
 470
 471 /* If Disable DVI, turn off pad */
 472 void viafb_dvi_disable(void)
 473 {
 474         if (viaparinfo->chip_info->
 475                 tmds_chip_info.output_interface == INTERFACE_TMDS)
 476                 /* Turn off TMDS power. */
 477                 viafb_write_reg(CRD2, VIACR,
 478                 viafb_read_reg(VIACR, CRD2) | 0x08);
 479 }
 480
 481 static void dvi_patch_skew_dvp0(void)
 482 {
 483         /* Reset data driving first: */
 484         viafb_write_reg_mask(SR1B, VIASR, 0, BIT1);
 485         viafb_write_reg_mask(SR2A, VIASR, 0, BIT4);
 486
 487         switch (viaparinfo->chip_info->gfx_chip_name) {
 488         case UNICHROME_P4M890:
 489                 {
 490                         if ((viaparinfo->tmds_setting_info->h_active == 1600) &&
 491                                 (viaparinfo->tmds_setting_info->v_active ==
 492                                 1200))
 493                                 viafb_write_reg_mask(CR96, VIACR, 0x03,
 494                                                BIT0 + BIT1 + BIT2);
 495                         else
 496                                 viafb_write_reg_mask(CR96, VIACR, 0x07,
 497                                                BIT0 + BIT1 + BIT2);
 498                         break;
 499                 }
 500
 501         case UNICHROME_P4M900:
 502                 {
 503                         viafb_write_reg_mask(CR96, VIACR, 0x07,
 504                                        BIT0 + BIT1 + BIT2 + BIT3);
 505                         viafb_write_reg_mask(SR1B, VIASR, 0x02, BIT1);
 506                         viafb_write_reg_mask(SR2A, VIASR, 0x10, BIT4);
 507                         break;
 508                 }
 509
 510         default:
 511                 {
 512                         break;
 513                 }
 514         }
 515 }
 516
 517 static void dvi_patch_skew_dvp_low(void)
 518 {
 519         switch (viaparinfo->chip_info->gfx_chip_name) {
 520         case UNICHROME_K8M890:
 521                 {
 522                         viafb_write_reg_mask(CR99, VIACR, 0x03, BIT0 + BIT1);
 523                         break;
 524                 }
 525
 526         case UNICHROME_P4M900:
 527                 {
 528                         viafb_write_reg_mask(CR99, VIACR, 0x08,
 529                                        BIT0 + BIT1 + BIT2 + BIT3);
 530                         break;
 531                 }
 532
 533         case UNICHROME_P4M890:
 534                 {
 535                         viafb_write_reg_mask(CR99, VIACR, 0x0F,
 536                                        BIT0 + BIT1 + BIT2 + BIT3);
 537                         break;
 538                 }
 539
 540         default:
 541                 {
 542                         break;
 543                 }
 544         }
 545 }
 546
 547 /* If Enable DVI, turn off pad */
 548 void viafb_dvi_enable(void)
 549 {
 550         u8 data;
 551
 552         switch (viaparinfo->chip_info->tmds_chip_info.output_interface) {
 553         case INTERFACE_DVP0:
 554                 viafb_write_reg_mask(CR6B, VIACR, 0x01, BIT0);
 555                 viafb_write_reg_mask(CR6C, VIACR, 0x21, BIT0 + BIT5);
 556                 dvi_patch_skew_dvp0();
 557                 if (viaparinfo->chip_info->gfx_chip_name == UNICHROME_CLE266)
 558                         tmds_register_write(0x88, 0x3b);
 559                 else
 560                         /*clear CR91[5] to direct on display period
 561                            in the secondary diplay path */
 562                         via_write_reg_mask(VIACR, 0x91, 0x00, 0x20);
 563                 break;
 564
 565         case INTERFACE_DVP1:
 566                 if (viaparinfo->chip_info->gfx_chip_name == UNICHROME_CLE266)
 567                         viafb_write_reg_mask(CR93, VIACR, 0x21, BIT0 + BIT5);
 568
 569                 /*fix dvi cann't be enabled with MB VT5718C4 - Al Zhang */
 570                 if (viaparinfo->chip_info->gfx_chip_name == UNICHROME_CLE266)
 571                         tmds_register_write(0x88, 0x3b);
 572                 else
 573                         /*clear CR91[5] to direct on display period
 574                           in the secondary diplay path */
 575                         via_write_reg_mask(VIACR, 0x91, 0x00, 0x20);
 576
 577                 /*fix DVI cannot enable on EPIA-M board */
 578                 if (viafb_platform_epia_dvi == 1) {
 579                         viafb_write_reg_mask(CR91, VIACR, 0x1f, 0x1f);
 580                         viafb_write_reg_mask(CR88, VIACR, 0x00, BIT6 + BIT0);
 581                         if (viafb_bus_width == 24) {
 582                                 if (viafb_device_lcd_dualedge == 1)
 583                                         data = 0x3F;
 584                                 else
 585                                         data = 0x37;
 586                                 viafb_i2c_writebyte(viaparinfo->chip_info->
 587                                         tmds_chip_info.i2c_port,
 588                                         viaparinfo->chip_info->
 589                                         tmds_chip_info.tmds_chip_slave_addr,
 590                                         0x08, data);
 591                         }
 592                 }
 593                 break;
 594
 595         case INTERFACE_DFP_HIGH:
 596                 if (viaparinfo->chip_info->gfx_chip_name != UNICHROME_CLE266)
 597                         via_write_reg_mask(VIACR, CR97, 0x03, 0x03);
 598
 599                 via_write_reg_mask(VIACR, 0x91, 0x00, 0x20);
 600                 break;
 601
 602         case INTERFACE_DFP_LOW:
 603                 if (viaparinfo->chip_info->gfx_chip_name == UNICHROME_CLE266)
 604                         break;
 605
 606                 dvi_patch_skew_dvp_low();
 607                 via_write_reg_mask(VIACR, 0x91, 0x00, 0x20);
 608                 break;
 609
 610         case INTERFACE_TMDS:
 611                 /* Turn on Display period in the panel path. */
 612                 viafb_write_reg_mask(CR91, VIACR, 0, BIT7);
 613
 614                 /* Turn on TMDS power. */
 615                 viafb_write_reg_mask(CRD2, VIACR, 0, BIT3);
 616                 break;
 617         }
 618
 619         if (viaparinfo->tmds_setting_info->iga_path == IGA2) {
 620                 /* Disable LCD Scaling */
 621                 viafb_write_reg_mask(CR79, VIACR, 0x00, BIT0);
 622         }
 623 }