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 
check_tmds_chip(int device_id_subaddr,int device_id)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 
viafb_init_dvi_size(struct tmds_chip_information * tmds_chip,struct tmds_setting_information * tmds_setting)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 
viafb_tmds_trasmitter_identify(void)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 
tmds_register_write(int index,u8 data)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 
tmds_register_read(int index)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 
tmds_register_read_bytes(int index,u8 * buff,int buff_len)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 */
viafb_dvi_set_mode(struct VideoModeTable * mode,int mode_bpp,int set_iga)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 */
viafb_dvi_sense(void)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 */
viafb_dvi_query_EDID(void)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 */
dvi_get_panel_size_from_DDCv1(struct tmds_chip_information * tmds_chip,struct tmds_setting_information * tmds_setting)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 */
dvi_get_panel_size_from_DDCv2(struct tmds_chip_information * tmds_chip,struct tmds_setting_information * tmds_setting)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 */
viafb_dvi_disable(void)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 
dvi_patch_skew_dvp0(void)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 
dvi_patch_skew_dvp_low(void)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 */
viafb_dvi_enable(void)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 }
624