LCD的参数适配

LCD的参数和其他外设一样在fex文件里修改
像分辨率和画布偏移之类的，都在以下字段：

lcd_x = 800
lcd_y = 480
lcd_dclk_freq = 33
lcd_hv_hspw = 23
lcd_hbp = 46
lcd_ht = 1055
lcd_hv_vspw = 1
lcd_vbp = 10
lcd_vt = 1050

例如改成1024*768

lcd_x = 		1024
lcd_y = 		768
lcd_dclk_freq = 65
lcd_hv_vspw = 	6
lcd_hv_hspw = 	136
lcd_hbp = 		180
lcd_ht = 		1344
lcd_vbp = 		29
lcd_vt = 		1612

在超分辨率使用时，注意以下代码（具体查看源码）的限制

/* hv panel, CPU panel and ttl panel */
if (info->lcd_if == 0 || info->lcd_if == 1 || info->lcd_if == 2) {
	/* MHz */
	if (lcd_dclk_freq > 2000000 && lcd_dclk_freq <= 297000000) {
		/* divider for dclk in tcon0 */
		*divider = 297000000 / (lcd_dclk_freq);
		pll_freq = lcd_dclk_freq * (*divider);
	} else {
		return -1;
	}
} 

以下是未整理的移植时的手记，可以参考：

drivers/video/sunxi_display.c
	video_hw_init
drivers/video/videomodes.c
	int video_get_params (struct ctfb_res_modes *pPar, char *penv)
	mode: 0~9	640*480~1920*1200,默认0
	x:
	y:
	refresh:
	le:left_margin
	ri:right_margin
	up:upper_margin
	lo:lower_margin
	hs:hsync_len
	vs:vsync_len
	sync:sync
		#define FB_SYNC_HOR_HIGH_ACT	1	/* horizontal sync high active	*/
		#define FB_SYNC_VERT_HIGH_ACT	2	/* vertical sync high active	*/
		#define FB_SYNC_EXT		4	/* external sync		*/
		#define FB_SYNC_COMP_HIGH_ACT	8	/* composite sync high active	*/
		#define FB_SYNC_BROADCAST	16	/* broadcast video timings	*/
							/* vtotal = 144d/288n/576i => PAL  */
							/* vtotal = 121d/242n/484i => NTSC */
		#define FB_SYNC_ON_GREEN	32	/* sync on green */
	vmode:vmode
		#define FB_VMODE_NONINTERLACED	0	/* non interlaced */
		#define FB_VMODE_INTERLACED	1	/* interlaced	*/
		#define FB_VMODE_DOUBLE		2	/* double scan */
		#define FB_VMODE_ODD_FLD_FIRST	4	/* interlaced: top line first */
	pclk:pixclock
	pclk_khz:pixclock_khz
	depth: 色深
	
	bp = mode->hsync_len + mode->left_margin;
			10				(43-10)=33
	total = mode->xres + mode->right_margin + bp;
				480			8				43
				
	bp = mode->vsync_len + mode->upper_margin;
			10					(12-10)=2
	total = mode->yres + mode->lower_margin + bp;
			272				4				12
	x:480,y:272,depth:18,pclk_khz:9000,le:33,ri:8,up:2,lo:4,hs:10,vs:10,sync:0,vmode:0
	x:800,y:480,depth:18,pclk_khz:33000,le:100,ri:170,up:35,lo:2,hs:10,vs:10,sync:0,vmode:0

Setting up a 480x272 lcd console (overscan 0x0) 背光闪了下
drivers/video/sunxi_display.c
	video_hw_init
		sunxi_mode_set(mode, fb_dma_addr);
			static void sunxi_lcdc_backlight_enable(void)

hsync + hbp(back porch) + X len + hfp(front porch)

hb(H blanking)

hbp相当于画面在画布中的偏移，
屏幕在左边和上边都有一部分不能显示的等待区域，要调整hbp移出这部分，
否则会有一部分在屏幕外不显示
hsync值只要大于1即可