369 lines
9.2 KiB
C
369 lines
9.2 KiB
C
/*
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* linux/drivers/video/fbcvt.c - VESA(TM) Coordinated Video Timings
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*
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* Copyright (C) 2005 Antonino Daplas <adaplas@pol.net>
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*
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* Based from the VESA(TM) Coordinated Video Timing Generator by
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* Graham Loveridge April 9, 2003 available at
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* http://www.elo.utfsm.cl/~elo212/docs/CVTd6r1.xls
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file COPYING in the main directory of this archive
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* for more details.
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*
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*/
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#include <linux/fb.h>
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#include <linux/slab.h>
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#define FB_CVT_CELLSIZE 8
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#define FB_CVT_GTF_C 40
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#define FB_CVT_GTF_J 20
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#define FB_CVT_GTF_K 128
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#define FB_CVT_GTF_M 600
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#define FB_CVT_MIN_VSYNC_BP 550
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#define FB_CVT_MIN_VPORCH 3
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#define FB_CVT_MIN_BPORCH 6
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#define FB_CVT_RB_MIN_VBLANK 460
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#define FB_CVT_RB_HBLANK 160
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#define FB_CVT_RB_V_FPORCH 3
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#define FB_CVT_FLAG_REDUCED_BLANK 1
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#define FB_CVT_FLAG_MARGINS 2
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#define FB_CVT_FLAG_INTERLACED 4
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struct fb_cvt_data {
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u32 xres;
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u32 yres;
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u32 refresh;
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u32 f_refresh;
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u32 pixclock;
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u32 hperiod;
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u32 hblank;
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u32 hfreq;
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u32 htotal;
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u32 vtotal;
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u32 vsync;
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u32 hsync;
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u32 h_front_porch;
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u32 h_back_porch;
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u32 v_front_porch;
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u32 v_back_porch;
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u32 h_margin;
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u32 v_margin;
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u32 interlace;
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u32 aspect_ratio;
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u32 active_pixels;
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u32 flags;
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u32 status;
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};
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static const unsigned char fb_cvt_vbi_tab[] = {
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4, /* 4:3 */
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5, /* 16:9 */
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6, /* 16:10 */
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7, /* 5:4 */
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7, /* 15:9 */
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8, /* reserved */
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9, /* reserved */
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10 /* custom */
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};
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/* returns hperiod * 1000 */
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static u32 fb_cvt_hperiod(struct fb_cvt_data *cvt)
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{
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u32 num = 1000000000/cvt->f_refresh;
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u32 den;
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if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK) {
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num -= FB_CVT_RB_MIN_VBLANK * 1000;
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den = 2 * (cvt->yres/cvt->interlace + 2 * cvt->v_margin);
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} else {
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num -= FB_CVT_MIN_VSYNC_BP * 1000;
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den = 2 * (cvt->yres/cvt->interlace + cvt->v_margin * 2
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+ FB_CVT_MIN_VPORCH + cvt->interlace/2);
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}
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return 2 * (num/den);
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}
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/* returns ideal duty cycle * 1000 */
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static u32 fb_cvt_ideal_duty_cycle(struct fb_cvt_data *cvt)
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{
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u32 c_prime = (FB_CVT_GTF_C - FB_CVT_GTF_J) *
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(FB_CVT_GTF_K) + 256 * FB_CVT_GTF_J;
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u32 m_prime = (FB_CVT_GTF_K * FB_CVT_GTF_M);
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u32 h_period_est = cvt->hperiod;
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return (1000 * c_prime - ((m_prime * h_period_est)/1000))/256;
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}
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static u32 fb_cvt_hblank(struct fb_cvt_data *cvt)
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{
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u32 hblank = 0;
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if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)
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hblank = FB_CVT_RB_HBLANK;
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else {
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u32 ideal_duty_cycle = fb_cvt_ideal_duty_cycle(cvt);
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u32 active_pixels = cvt->active_pixels;
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if (ideal_duty_cycle < 20000)
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hblank = (active_pixels * 20000)/
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(100000 - 20000);
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else {
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hblank = (active_pixels * ideal_duty_cycle)/
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(100000 - ideal_duty_cycle);
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}
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}
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hblank &= ~((2 * FB_CVT_CELLSIZE) - 1);
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return hblank;
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}
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static u32 fb_cvt_hsync(struct fb_cvt_data *cvt)
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{
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u32 hsync;
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if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)
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hsync = 32;
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else
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hsync = (FB_CVT_CELLSIZE * cvt->htotal)/100;
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hsync &= ~(FB_CVT_CELLSIZE - 1);
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return hsync;
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}
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static u32 fb_cvt_vbi_lines(struct fb_cvt_data *cvt)
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{
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u32 vbi_lines, min_vbi_lines, act_vbi_lines;
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if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK) {
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vbi_lines = (1000 * FB_CVT_RB_MIN_VBLANK)/cvt->hperiod + 1;
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min_vbi_lines = FB_CVT_RB_V_FPORCH + cvt->vsync +
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FB_CVT_MIN_BPORCH;
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} else {
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vbi_lines = (FB_CVT_MIN_VSYNC_BP * 1000)/cvt->hperiod + 1 +
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FB_CVT_MIN_VPORCH;
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min_vbi_lines = cvt->vsync + FB_CVT_MIN_BPORCH +
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FB_CVT_MIN_VPORCH;
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}
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if (vbi_lines < min_vbi_lines)
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act_vbi_lines = min_vbi_lines;
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else
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act_vbi_lines = vbi_lines;
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return act_vbi_lines;
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}
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static u32 fb_cvt_vtotal(struct fb_cvt_data *cvt)
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{
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u32 vtotal = cvt->yres/cvt->interlace;
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vtotal += 2 * cvt->v_margin + cvt->interlace/2 + fb_cvt_vbi_lines(cvt);
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vtotal |= cvt->interlace/2;
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return vtotal;
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}
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static u32 fb_cvt_pixclock(struct fb_cvt_data *cvt)
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{
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u32 pixclock;
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if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)
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pixclock = (cvt->f_refresh * cvt->vtotal * cvt->htotal)/1000;
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else
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pixclock = (cvt->htotal * 1000000)/cvt->hperiod;
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pixclock /= 250;
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pixclock *= 250;
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pixclock *= 1000;
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return pixclock;
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}
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static u32 fb_cvt_aspect_ratio(struct fb_cvt_data *cvt)
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{
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u32 xres = cvt->xres;
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u32 yres = cvt->yres;
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u32 aspect = -1;
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if (xres == (yres * 4)/3 && !((yres * 4) % 3))
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aspect = 0;
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else if (xres == (yres * 16)/9 && !((yres * 16) % 9))
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aspect = 1;
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else if (xres == (yres * 16)/10 && !((yres * 16) % 10))
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aspect = 2;
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else if (xres == (yres * 5)/4 && !((yres * 5) % 4))
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aspect = 3;
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else if (xres == (yres * 15)/9 && !((yres * 15) % 9))
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aspect = 4;
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else {
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printk(KERN_INFO "fbcvt: Aspect ratio not CVT "
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"standard\n");
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aspect = 7;
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cvt->status = 1;
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}
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return aspect;
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}
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static void fb_cvt_print_name(struct fb_cvt_data *cvt)
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{
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u32 pixcount, pixcount_mod;
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int size = 256;
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int off = 0;
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u8 *buf;
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buf = kzalloc(size, GFP_KERNEL);
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if (!buf)
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return;
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pixcount = (cvt->xres * (cvt->yres/cvt->interlace))/1000000;
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pixcount_mod = (cvt->xres * (cvt->yres/cvt->interlace)) % 1000000;
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pixcount_mod /= 1000;
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off += scnprintf(buf + off, size - off, "fbcvt: %dx%d@%d: CVT Name - ",
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cvt->xres, cvt->yres, cvt->refresh);
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if (cvt->status) {
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off += scnprintf(buf + off, size - off,
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"Not a CVT standard - %d.%03d Mega Pixel Image\n",
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pixcount, pixcount_mod);
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} else {
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if (pixcount)
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off += scnprintf(buf + off, size - off, "%d", pixcount);
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off += scnprintf(buf + off, size - off, ".%03dM", pixcount_mod);
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if (cvt->aspect_ratio == 0)
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off += scnprintf(buf + off, size - off, "3");
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else if (cvt->aspect_ratio == 3)
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off += scnprintf(buf + off, size - off, "4");
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else if (cvt->aspect_ratio == 1 || cvt->aspect_ratio == 4)
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off += scnprintf(buf + off, size - off, "9");
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else if (cvt->aspect_ratio == 2)
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off += scnprintf(buf + off, size - off, "A");
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if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)
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off += scnprintf(buf + off, size - off, "-R");
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}
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printk(KERN_INFO "%s\n", buf);
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kfree(buf);
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}
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static void fb_cvt_convert_to_mode(struct fb_cvt_data *cvt,
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struct fb_videomode *mode)
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{
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mode->refresh = cvt->f_refresh;
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mode->pixclock = KHZ2PICOS(cvt->pixclock/1000);
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mode->left_margin = cvt->h_back_porch;
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mode->right_margin = cvt->h_front_porch;
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mode->hsync_len = cvt->hsync;
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mode->upper_margin = cvt->v_back_porch;
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mode->lower_margin = cvt->v_front_porch;
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mode->vsync_len = cvt->vsync;
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mode->sync &= ~(FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT);
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if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)
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mode->sync |= FB_SYNC_HOR_HIGH_ACT;
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else
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mode->sync |= FB_SYNC_VERT_HIGH_ACT;
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}
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/*
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* fb_find_mode_cvt - calculate mode using VESA(TM) CVT
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* @mode: pointer to fb_videomode; xres, yres, refresh and vmode must be
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* pre-filled with the desired values
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* @margins: add margin to calculation (1.8% of xres and yres)
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* @rb: compute with reduced blanking (for flatpanels)
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*
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* RETURNS:
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* 0 for success
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* @mode is filled with computed values. If interlaced, the refresh field
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* will be filled with the field rate (2x the frame rate)
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*
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* DESCRIPTION:
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* Computes video timings using VESA(TM) Coordinated Video Timings
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*/
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int fb_find_mode_cvt(struct fb_videomode *mode, int margins, int rb)
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{
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struct fb_cvt_data cvt;
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memset(&cvt, 0, sizeof(cvt));
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if (margins)
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cvt.flags |= FB_CVT_FLAG_MARGINS;
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if (rb)
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cvt.flags |= FB_CVT_FLAG_REDUCED_BLANK;
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if (mode->vmode & FB_VMODE_INTERLACED)
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cvt.flags |= FB_CVT_FLAG_INTERLACED;
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cvt.xres = mode->xres;
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cvt.yres = mode->yres;
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cvt.refresh = mode->refresh;
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cvt.f_refresh = cvt.refresh;
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cvt.interlace = 1;
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if (!cvt.xres || !cvt.yres || !cvt.refresh) {
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printk(KERN_INFO "fbcvt: Invalid input parameters\n");
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return 1;
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}
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if (!(cvt.refresh == 50 || cvt.refresh == 60 || cvt.refresh == 70 ||
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cvt.refresh == 85)) {
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printk(KERN_INFO "fbcvt: Refresh rate not CVT "
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"standard\n");
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cvt.status = 1;
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}
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cvt.xres &= ~(FB_CVT_CELLSIZE - 1);
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if (cvt.flags & FB_CVT_FLAG_INTERLACED) {
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cvt.interlace = 2;
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cvt.f_refresh *= 2;
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}
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if (cvt.flags & FB_CVT_FLAG_REDUCED_BLANK) {
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if (cvt.refresh != 60) {
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printk(KERN_INFO "fbcvt: 60Hz refresh rate "
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"advised for reduced blanking\n");
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cvt.status = 1;
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}
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}
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if (cvt.flags & FB_CVT_FLAG_MARGINS) {
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cvt.h_margin = (cvt.xres * 18)/1000;
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cvt.h_margin &= ~(FB_CVT_CELLSIZE - 1);
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cvt.v_margin = ((cvt.yres/cvt.interlace)* 18)/1000;
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}
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cvt.aspect_ratio = fb_cvt_aspect_ratio(&cvt);
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cvt.active_pixels = cvt.xres + 2 * cvt.h_margin;
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cvt.hperiod = fb_cvt_hperiod(&cvt);
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cvt.vsync = fb_cvt_vbi_tab[cvt.aspect_ratio];
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cvt.vtotal = fb_cvt_vtotal(&cvt);
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cvt.hblank = fb_cvt_hblank(&cvt);
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cvt.htotal = cvt.active_pixels + cvt.hblank;
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cvt.hsync = fb_cvt_hsync(&cvt);
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cvt.pixclock = fb_cvt_pixclock(&cvt);
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cvt.hfreq = cvt.pixclock/cvt.htotal;
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cvt.h_back_porch = cvt.hblank/2 + cvt.h_margin;
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cvt.h_front_porch = cvt.hblank - cvt.hsync - cvt.h_back_porch +
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2 * cvt.h_margin;
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cvt.v_front_porch = 3 + cvt.v_margin;
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cvt.v_back_porch = cvt.vtotal - cvt.yres/cvt.interlace -
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cvt.v_front_porch - cvt.vsync;
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fb_cvt_print_name(&cvt);
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fb_cvt_convert_to_mode(&cvt, mode);
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return 0;
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}
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