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1/*2 * linux/drivers/video/fbcvt.c - VESA(TM) Coordinated Video Timings3 *4 * Copyright (C) 2005 Antonino Daplas <adaplas@pol.net>5 *6 * Based from the VESA(TM) Coordinated Video Timing Generator by7 * Graham Loveridge April 9, 2003 available at8 * http://www.elo.utfsm.cl/~elo212/docs/CVTd6r1.xls9 *10 * This file is subject to the terms and conditions of the GNU General Public11 * License. See the file COPYING in the main directory of this archive12 * for more details.13 *14 */15#include <linux/fb.h>16#include <linux/slab.h>17 18#define FB_CVT_CELLSIZE 819#define FB_CVT_GTF_C 4020#define FB_CVT_GTF_J 2021#define FB_CVT_GTF_K 12822#define FB_CVT_GTF_M 60023#define FB_CVT_MIN_VSYNC_BP 55024#define FB_CVT_MIN_VPORCH 325#define FB_CVT_MIN_BPORCH 626 27#define FB_CVT_RB_MIN_VBLANK 46028#define FB_CVT_RB_HBLANK 16029#define FB_CVT_RB_V_FPORCH 330 31#define FB_CVT_FLAG_REDUCED_BLANK 132#define FB_CVT_FLAG_MARGINS 233#define FB_CVT_FLAG_INTERLACED 434 35struct fb_cvt_data {36 u32 xres;37 u32 yres;38 u32 refresh;39 u32 f_refresh;40 u32 pixclock;41 u32 hperiod;42 u32 hblank;43 u32 hfreq;44 u32 htotal;45 u32 vtotal;46 u32 vsync;47 u32 hsync;48 u32 h_front_porch;49 u32 h_back_porch;50 u32 v_front_porch;51 u32 v_back_porch;52 u32 h_margin;53 u32 v_margin;54 u32 interlace;55 u32 aspect_ratio;56 u32 active_pixels;57 u32 flags;58 u32 status;59};60 61static const unsigned char fb_cvt_vbi_tab[] = {62 4, /* 4:3 */63 5, /* 16:9 */64 6, /* 16:10 */65 7, /* 5:4 */66 7, /* 15:9 */67 8, /* reserved */68 9, /* reserved */69 10 /* custom */70};71 72/* returns hperiod * 1000 */73static u32 fb_cvt_hperiod(struct fb_cvt_data *cvt)74{75 u32 num = 1000000000/cvt->f_refresh;76 u32 den;77 78 if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK) {79 num -= FB_CVT_RB_MIN_VBLANK * 1000;80 den = 2 * (cvt->yres/cvt->interlace + 2 * cvt->v_margin);81 } else {82 num -= FB_CVT_MIN_VSYNC_BP * 1000;83 den = 2 * (cvt->yres/cvt->interlace + cvt->v_margin * 284 + FB_CVT_MIN_VPORCH + cvt->interlace/2);85 }86 87 return 2 * (num/den);88}89 90/* returns ideal duty cycle * 1000 */91static u32 fb_cvt_ideal_duty_cycle(struct fb_cvt_data *cvt)92{93 u32 c_prime = (FB_CVT_GTF_C - FB_CVT_GTF_J) *94 (FB_CVT_GTF_K) + 256 * FB_CVT_GTF_J;95 u32 m_prime = (FB_CVT_GTF_K * FB_CVT_GTF_M);96 u32 h_period_est = cvt->hperiod;97 98 return (1000 * c_prime - ((m_prime * h_period_est)/1000))/256;99}100 101static u32 fb_cvt_hblank(struct fb_cvt_data *cvt)102{103 u32 hblank = 0;104 105 if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)106 hblank = FB_CVT_RB_HBLANK;107 else {108 u32 ideal_duty_cycle = fb_cvt_ideal_duty_cycle(cvt);109 u32 active_pixels = cvt->active_pixels;110 111 if (ideal_duty_cycle < 20000)112 hblank = (active_pixels * 20000)/113 (100000 - 20000);114 else {115 hblank = (active_pixels * ideal_duty_cycle)/116 (100000 - ideal_duty_cycle);117 }118 }119 120 hblank &= ~((2 * FB_CVT_CELLSIZE) - 1);121 122 return hblank;123}124 125static u32 fb_cvt_hsync(struct fb_cvt_data *cvt)126{127 u32 hsync;128 129 if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)130 hsync = 32;131 else132 hsync = (FB_CVT_CELLSIZE * cvt->htotal)/100;133 134 hsync &= ~(FB_CVT_CELLSIZE - 1);135 return hsync;136}137 138static u32 fb_cvt_vbi_lines(struct fb_cvt_data *cvt)139{140 u32 vbi_lines, min_vbi_lines, act_vbi_lines;141 142 if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK) {143 vbi_lines = (1000 * FB_CVT_RB_MIN_VBLANK)/cvt->hperiod + 1;144 min_vbi_lines = FB_CVT_RB_V_FPORCH + cvt->vsync +145 FB_CVT_MIN_BPORCH;146 147 } else {148 vbi_lines = (FB_CVT_MIN_VSYNC_BP * 1000)/cvt->hperiod + 1 +149 FB_CVT_MIN_VPORCH;150 min_vbi_lines = cvt->vsync + FB_CVT_MIN_BPORCH +151 FB_CVT_MIN_VPORCH;152 }153 154 if (vbi_lines < min_vbi_lines)155 act_vbi_lines = min_vbi_lines;156 else157 act_vbi_lines = vbi_lines;158 159 return act_vbi_lines;160}161 162static u32 fb_cvt_vtotal(struct fb_cvt_data *cvt)163{164 u32 vtotal = cvt->yres/cvt->interlace;165 166 vtotal += 2 * cvt->v_margin + cvt->interlace/2 + fb_cvt_vbi_lines(cvt);167 vtotal |= cvt->interlace/2;168 169 return vtotal;170}171 172static u32 fb_cvt_pixclock(struct fb_cvt_data *cvt)173{174 u32 pixclock;175 176 if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)177 pixclock = (cvt->f_refresh * cvt->vtotal * cvt->htotal)/1000;178 else179 pixclock = (cvt->htotal * 1000000)/cvt->hperiod;180 181 pixclock /= 250;182 pixclock *= 250;183 pixclock *= 1000;184 185 return pixclock;186}187 188static u32 fb_cvt_aspect_ratio(struct fb_cvt_data *cvt)189{190 u32 xres = cvt->xres;191 u32 yres = cvt->yres;192 u32 aspect = -1;193 194 if (xres == (yres * 4)/3 && !((yres * 4) % 3))195 aspect = 0;196 else if (xres == (yres * 16)/9 && !((yres * 16) % 9))197 aspect = 1;198 else if (xres == (yres * 16)/10 && !((yres * 16) % 10))199 aspect = 2;200 else if (xres == (yres * 5)/4 && !((yres * 5) % 4))201 aspect = 3;202 else if (xres == (yres * 15)/9 && !((yres * 15) % 9))203 aspect = 4;204 else {205 printk(KERN_INFO "fbcvt: Aspect ratio not CVT "206 "standard\n");207 aspect = 7;208 cvt->status = 1;209 }210 211 return aspect;212}213 214static void fb_cvt_print_name(struct fb_cvt_data *cvt)215{216 u32 pixcount, pixcount_mod;217 int size = 256;218 int off = 0;219 u8 *buf;220 221 buf = kzalloc(size, GFP_KERNEL);222 if (!buf)223 return;224 225 pixcount = (cvt->xres * (cvt->yres/cvt->interlace))/1000000;226 pixcount_mod = (cvt->xres * (cvt->yres/cvt->interlace)) % 1000000;227 pixcount_mod /= 1000;228 229 off += scnprintf(buf + off, size - off, "fbcvt: %dx%d@%d: CVT Name - ",230 cvt->xres, cvt->yres, cvt->refresh);231 232 if (cvt->status) {233 off += scnprintf(buf + off, size - off,234 "Not a CVT standard - %d.%03d Mega Pixel Image\n",235 pixcount, pixcount_mod);236 } else {237 if (pixcount)238 off += scnprintf(buf + off, size - off, "%d", pixcount);239 240 off += scnprintf(buf + off, size - off, ".%03dM", pixcount_mod);241 242 if (cvt->aspect_ratio == 0)243 off += scnprintf(buf + off, size - off, "3");244 else if (cvt->aspect_ratio == 3)245 off += scnprintf(buf + off, size - off, "4");246 else if (cvt->aspect_ratio == 1 || cvt->aspect_ratio == 4)247 off += scnprintf(buf + off, size - off, "9");248 else if (cvt->aspect_ratio == 2)249 off += scnprintf(buf + off, size - off, "A");250 251 if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)252 off += scnprintf(buf + off, size - off, "-R");253 }254 255 printk(KERN_INFO "%s\n", buf);256 kfree(buf);257}258 259static void fb_cvt_convert_to_mode(struct fb_cvt_data *cvt,260 struct fb_videomode *mode)261{262 mode->refresh = cvt->f_refresh;263 mode->pixclock = KHZ2PICOS(cvt->pixclock/1000);264 mode->left_margin = cvt->h_back_porch;265 mode->right_margin = cvt->h_front_porch;266 mode->hsync_len = cvt->hsync;267 mode->upper_margin = cvt->v_back_porch;268 mode->lower_margin = cvt->v_front_porch;269 mode->vsync_len = cvt->vsync;270 271 mode->sync &= ~(FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT);272 273 if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)274 mode->sync |= FB_SYNC_HOR_HIGH_ACT;275 else276 mode->sync |= FB_SYNC_VERT_HIGH_ACT;277}278 279/*280 * fb_find_mode_cvt - calculate mode using VESA(TM) CVT281 * @mode: pointer to fb_videomode; xres, yres, refresh and vmode must be282 * pre-filled with the desired values283 * @margins: add margin to calculation (1.8% of xres and yres)284 * @rb: compute with reduced blanking (for flatpanels)285 *286 * RETURNS:287 * 0 for success288 * @mode is filled with computed values. If interlaced, the refresh field289 * will be filled with the field rate (2x the frame rate)290 *291 * DESCRIPTION:292 * Computes video timings using VESA(TM) Coordinated Video Timings293 */294int fb_find_mode_cvt(struct fb_videomode *mode, int margins, int rb)295{296 struct fb_cvt_data cvt;297 298 memset(&cvt, 0, sizeof(cvt));299 300 if (margins)301 cvt.flags |= FB_CVT_FLAG_MARGINS;302 303 if (rb)304 cvt.flags |= FB_CVT_FLAG_REDUCED_BLANK;305 306 if (mode->vmode & FB_VMODE_INTERLACED)307 cvt.flags |= FB_CVT_FLAG_INTERLACED;308 309 cvt.xres = mode->xres;310 cvt.yres = mode->yres;311 cvt.refresh = mode->refresh;312 cvt.f_refresh = cvt.refresh;313 cvt.interlace = 1;314 315 if (!cvt.xres || !cvt.yres || !cvt.refresh) {316 printk(KERN_INFO "fbcvt: Invalid input parameters\n");317 return 1;318 }319 320 if (!(cvt.refresh == 50 || cvt.refresh == 60 || cvt.refresh == 70 ||321 cvt.refresh == 85)) {322 printk(KERN_INFO "fbcvt: Refresh rate not CVT "323 "standard\n");324 cvt.status = 1;325 }326 327 cvt.xres &= ~(FB_CVT_CELLSIZE - 1);328 329 if (cvt.flags & FB_CVT_FLAG_INTERLACED) {330 cvt.interlace = 2;331 cvt.f_refresh *= 2;332 }333 334 if (cvt.flags & FB_CVT_FLAG_REDUCED_BLANK) {335 if (cvt.refresh != 60) {336 printk(KERN_INFO "fbcvt: 60Hz refresh rate "337 "advised for reduced blanking\n");338 cvt.status = 1;339 }340 }341 342 if (cvt.flags & FB_CVT_FLAG_MARGINS) {343 cvt.h_margin = (cvt.xres * 18)/1000;344 cvt.h_margin &= ~(FB_CVT_CELLSIZE - 1);345 cvt.v_margin = ((cvt.yres/cvt.interlace)* 18)/1000;346 }347 348 cvt.aspect_ratio = fb_cvt_aspect_ratio(&cvt);349 cvt.active_pixels = cvt.xres + 2 * cvt.h_margin;350 cvt.hperiod = fb_cvt_hperiod(&cvt);351 cvt.vsync = fb_cvt_vbi_tab[cvt.aspect_ratio];352 cvt.vtotal = fb_cvt_vtotal(&cvt);353 cvt.hblank = fb_cvt_hblank(&cvt);354 cvt.htotal = cvt.active_pixels + cvt.hblank;355 cvt.hsync = fb_cvt_hsync(&cvt);356 cvt.pixclock = fb_cvt_pixclock(&cvt);357 cvt.hfreq = cvt.pixclock/cvt.htotal;358 cvt.h_back_porch = cvt.hblank/2 + cvt.h_margin;359 cvt.h_front_porch = cvt.hblank - cvt.hsync - cvt.h_back_porch +360 2 * cvt.h_margin;361 cvt.v_front_porch = 3 + cvt.v_margin;362 cvt.v_back_porch = cvt.vtotal - cvt.yres/cvt.interlace -363 cvt.v_front_porch - cvt.vsync;364 fb_cvt_print_name(&cvt);365 fb_cvt_convert_to_mode(&cvt, mode);366 367 return 0;368}369