/* * linux/drivers/video/fbcvt.c - VESA(TM) Coordinated Video Timings * * Copyright (C) 2005 Antonino Daplas <adaplas@pol.net> * * Based from the VESA(TM) Coordinated Video Timing Generator by * Graham Loveridge April 9, 2003 available at * http://www.vesa.org/public/CVT/CVTd6r1.xls * * This file is subject to the terms and conditions of the GNU General Public * License. See the file COPYING in the main directory of this archive * for more details. * */ #include <linux/fb.h> #define FB_CVT_CELLSIZE 8 #define FB_CVT_GTF_C 40 #define FB_CVT_GTF_J 20 #define FB_CVT_GTF_K 128 #define FB_CVT_GTF_M 600 #define FB_CVT_MIN_VSYNC_BP 550 #define FB_CVT_MIN_VPORCH 3 #define FB_CVT_MIN_BPORCH 6 #define FB_CVT_RB_MIN_VBLANK 460 #define FB_CVT_RB_HBLANK 160 #define FB_CVT_RB_V_FPORCH 3 #define FB_CVT_FLAG_REDUCED_BLANK 1 #define FB_CVT_FLAG_MARGINS 2 #define FB_CVT_FLAG_INTERLACED 4 struct fb_cvt_data { u32 xres; u32 yres; u32 refresh; u32 f_refresh; u32 pixclock; u32 hperiod; u32 hblank; u32 hfreq; u32 htotal; u32 vtotal; u32 vsync; u32 hsync; u32 h_front_porch; u32 h_back_porch; u32 v_front_porch; u32 v_back_porch; u32 h_margin; u32 v_margin; u32 interlace; u32 aspect_ratio; u32 active_pixels; u32 flags; u32 status; }; static int fb_cvt_vbi_tab[] = { 4, /* 4:3 */ 5, /* 16:9 */ 6, /* 16:10 */ 7, /* 5:4 */ 7, /* 15:9 */ 8, /* reserved */ 9, /* reserved */ 10 /* custom */ }; /* returns hperiod * 1000 */ static u32 fb_cvt_hperiod(struct fb_cvt_data *cvt) { u32 num = 1000000000/cvt->f_refresh; u32 den; if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK) { num -= FB_CVT_RB_MIN_VBLANK * 1000; den = 2 * (cvt->yres/cvt->interlace + 2 * cvt->v_margin); } else { num -= FB_CVT_MIN_VSYNC_BP * 1000; den = 2 * (cvt->yres/cvt->interlace + cvt->v_margin * 2 + FB_CVT_MIN_VPORCH + cvt->interlace/2); } return 2 * (num/den); } /* returns ideal duty cycle * 1000 */ static u32 fb_cvt_ideal_duty_cycle(struct fb_cvt_data *cvt) { u32 c_prime = (FB_CVT_GTF_C - FB_CVT_GTF_J) * (FB_CVT_GTF_K) + 256 * FB_CVT_GTF_J; u32 m_prime = (FB_CVT_GTF_K * FB_CVT_GTF_M); u32 h_period_est = cvt->hperiod; return (1000 * c_prime - ((m_prime * h_period_est)/1000))/256; } static u32 fb_cvt_hblank(struct fb_cvt_data *cvt) { u32 hblank = 0; if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK) hblank = FB_CVT_RB_HBLANK; else { u32 ideal_duty_cycle = fb_cvt_ideal_duty_cycle(cvt); u32 active_pixels = cvt->active_pixels; if (ideal_duty_cycle < 20000) hblank = (active_pixels * 20000)/ (100000 - 20000); else { hblank = (active_pixels * ideal_duty_cycle)/ (100000 - ideal_duty_cycle); } } hblank &= ~((2 * FB_CVT_CELLSIZE) - 1); return hblank; } static u32 fb_cvt_hsync(struct fb_cvt_data *cvt) { u32 hsync; if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK) hsync = 32; else hsync = (FB_CVT_CELLSIZE * cvt->htotal)/100; hsync &= ~(FB_CVT_CELLSIZE - 1); return hsync; } static u32 fb_cvt_vbi_lines(struct fb_cvt_data *cvt) { u32 vbi_lines, min_vbi_lines, act_vbi_lines; if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK) { vbi_lines = (1000 * FB_CVT_RB_MIN_VBLANK)/cvt->hperiod + 1; min_vbi_lines = FB_CVT_RB_V_FPORCH + cvt->vsync + FB_CVT_MIN_BPORCH; } else { vbi_lines = (FB_CVT_MIN_VSYNC_BP * 1000)/cvt->hperiod + 1 + FB_CVT_MIN_VPORCH; min_vbi_lines = cvt->vsync + FB_CVT_MIN_BPORCH + FB_CVT_MIN_VPORCH; } if (vbi_lines < min_vbi_lines) act_vbi_lines = min_vbi_lines; else act_vbi_lines = vbi_lines; return act_vbi_lines; } static u32 fb_cvt_vtotal(struct fb_cvt_data *cvt) { u32 vtotal = cvt->yres/cvt->interlace; vtotal += 2 * cvt->v_margin + cvt->interlace/2 + fb_cvt_vbi_lines(cvt); vtotal |= cvt->interlace/2; return vtotal; } static u32 fb_cvt_pixclock(struct fb_cvt_data *cvt) { u32 pixclock; if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK) pixclock = (cvt->f_refresh * cvt->vtotal * cvt->htotal)/1000; else pixclock = (cvt->htotal * 1000000)/cvt->hperiod; pixclock /= 250; pixclock *= 250; pixclock *= 1000; return pixclock; } static u32 fb_cvt_aspect_ratio(struct fb_cvt_data *cvt) { u32 xres = cvt->xres; u32 yres = cvt->yres; u32 aspect = -1; if (xres == (yres * 4)/3 && !((yres * 4) % 3)) aspect = 0; else if (xres == (yres * 16)/9 && !((yres * 16) % 9)) aspect = 1; else if (xres == (yres * 16)/10 && !((yres * 16) % 10)) aspect = 2; else if (xres == (yres * 5)/4 && !((yres * 5) % 4)) aspect = 3; else if (xres == (yres * 15)/9 && !((yres * 15) % 9)) aspect = 4; else { printk(KERN_INFO "fbcvt: Aspect ratio not CVT " "standard\n"); aspect = 7; cvt->status = 1; } return aspect; } static void fb_cvt_print_name(struct fb_cvt_data *cvt) { u32 pixcount, pixcount_mod; int cnt = 255, offset = 0, read = 0; u8 *buf = kzalloc(256, GFP_KERNEL); if (!buf) return; pixcount = (cvt->xres * (cvt->yres/cvt->interlace))/1000000; pixcount_mod = (cvt->xres * (cvt->yres/cvt->interlace)) % 1000000; pixcount_mod /= 1000; read = snprintf(buf+offset, cnt, "fbcvt: %dx%d@%d: CVT Name - ", cvt->xres, cvt->yres, cvt->refresh); offset += read; cnt -= read; if (cvt->status) snprintf(buf+offset, cnt, "Not a CVT standard - %d.%03d Mega " "Pixel Image\n", pixcount, pixcount_mod); else { if (pixcount) { read = snprintf(buf+offset, cnt, "%d", pixcount); cnt -= read; offset += read; } read = snprintf(buf+offset, cnt, ".%03dM", pixcount_mod); cnt -= read; offset += read; if (cvt->aspect_ratio == 0) read = snprintf(buf+offset, cnt, "3"); else if (cvt->aspect_ratio == 3) read = snprintf(buf+offset, cnt, "4"); else if (cvt->aspect_ratio == 1 || cvt->aspect_ratio == 4) read = snprintf(buf+offset, cnt, "9"); else if (cvt->aspect_ratio == 2) read = snprintf(buf+offset, cnt, "A"); else read = 0; cnt -= read; offset += read; if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK) { read = snprintf(buf+offset, cnt, "-R"); cnt -= read; offset += read; } } printk(KERN_INFO "%s\n", buf); kfree(buf); } static void fb_cvt_convert_to_mode(struct fb_cvt_data *cvt, struct fb_videomode *mode) { mode->refresh = cvt->f_refresh; mode->pixclock = KHZ2PICOS(cvt->pixclock/1000); mode->left_margin = cvt->h_back_porch; mode->right_margin = cvt->h_front_porch; mode->hsync_len = cvt->hsync; mode->upper_margin = cvt->v_back_porch; mode->lower_margin = cvt->v_front_porch; mode->vsync_len = cvt->vsync; mode->sync &= ~(FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT); if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK) mode->sync |= FB_SYNC_HOR_HIGH_ACT; else mode->sync |= FB_SYNC_VERT_HIGH_ACT; } /* * fb_find_mode_cvt - calculate mode using VESA(TM) CVT * @mode: pointer to fb_videomode; xres, yres, refresh and vmode must be * pre-filled with the desired values * @margins: add margin to calculation (1.8% of xres and yres) * @rb: compute with reduced blanking (for flatpanels) * * RETURNS: * 0 for success * @mode is filled with computed values. If interlaced, the refresh field * will be filled with the field rate (2x the frame rate) * * DESCRIPTION: * Computes video timings using VESA(TM) Coordinated Video Timings */ int fb_find_mode_cvt(struct fb_videomode *mode, int margins, int rb) { struct fb_cvt_data cvt; memset(&cvt, 0, sizeof(cvt)); if (margins) cvt.flags |= FB_CVT_FLAG_MARGINS; if (rb) cvt.flags |= FB_CVT_FLAG_REDUCED_BLANK; if (mode->vmode & FB_VMODE_INTERLACED) cvt.flags |= FB_CVT_FLAG_INTERLACED; cvt.xres = mode->xres; cvt.yres = mode->yres; cvt.refresh = mode->refresh; cvt.f_refresh = cvt.refresh; cvt.interlace = 1; if (!cvt.xres || !cvt.yres || !cvt.refresh) { printk(KERN_INFO "fbcvt: Invalid input parameters\n"); return 1; } if (!(cvt.refresh == 50 || cvt.refresh == 60 || cvt.refresh == 70 || cvt.refresh == 85)) { printk(KERN_INFO "fbcvt: Refresh rate not CVT " "standard\n"); cvt.status = 1; } cvt.xres &= ~(FB_CVT_CELLSIZE - 1); if (cvt.flags & FB_CVT_FLAG_INTERLACED) { cvt.interlace = 2; cvt.f_refresh *= 2; } if (cvt.flags & FB_CVT_FLAG_REDUCED_BLANK) { if (cvt.refresh != 60) { printk(KERN_INFO "fbcvt: 60Hz refresh rate " "advised for reduced blanking\n"); cvt.status = 1; } } if (cvt.flags & FB_CVT_FLAG_MARGINS) { cvt.h_margin = (cvt.xres * 18)/1000; cvt.h_margin &= ~(FB_CVT_CELLSIZE - 1); cvt.v_margin = ((cvt.yres/cvt.interlace)* 18)/1000; } cvt.aspect_ratio = fb_cvt_aspect_ratio(&cvt); cvt.active_pixels = cvt.xres + 2 * cvt.h_margin; cvt.hperiod = fb_cvt_hperiod(&cvt); cvt.vsync = fb_cvt_vbi_tab[cvt.aspect_ratio]; cvt.vtotal = fb_cvt_vtotal(&cvt); cvt.hblank = fb_cvt_hblank(&cvt); cvt.htotal = cvt.active_pixels + cvt.hblank; cvt.hsync = fb_cvt_hsync(&cvt); cvt.pixclock = fb_cvt_pixclock(&cvt); cvt.hfreq = cvt.pixclock/cvt.htotal; cvt.h_back_porch = cvt.hblank/2 + cvt.h_margin; cvt.h_front_porch = cvt.hblank - cvt.hsync - cvt.h_back_porch + 2 * cvt.h_margin; cvt.v_back_porch = 3 + cvt.v_margin; cvt.v_front_porch = cvt.vtotal - cvt.yres/cvt.interlace - cvt.v_back_porch - cvt.vsync; fb_cvt_print_name(&cvt); fb_cvt_convert_to_mode(&cvt, mode); return 0; } EXPORT_SYMBOL(fb_find_mode_cvt);