mc68x328fb.c

S3C44B0X下的LCD （framebuffer）驱动资料与相关代码

     *  Pan or Wrap the Display
     *
     *  This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
     */

static int mc68x328fb_pan_display(struct fb_var_screeninfo *var, int con,
			   struct fb_info *info)
{
    if (var->vmode & FB_VMODE_YWRAP) {
	if (var->yoffset < 0 ||
	    var->yoffset >= fb_display[con].var.yres_virtual ||
	    var->xoffset)
	    return -EINVAL;
    } else {
	if (var->xoffset+fb_display[con].var.xres >
	    fb_display[con].var.xres_virtual ||
	    var->yoffset+fb_display[con].var.yres >
	    fb_display[con].var.yres_virtual)
	    return -EINVAL;
    }
    fb_display[con].var.xoffset = var->xoffset;
    fb_display[con].var.yoffset = var->yoffset;
    if (var->vmode & FB_VMODE_YWRAP)
	fb_display[con].var.vmode |= FB_VMODE_YWRAP;
    else
	fb_display[con].var.vmode &= ~FB_VMODE_YWRAP;
    return 0;
}

    /*
     *  Get the Colormap
     */

static int mc68x328fb_get_cmap(struct fb_cmap *cmap, int kspc, int con,
			struct fb_info *info)
{
    if (con == currcon) /* current console? */
	return fb_get_cmap(cmap, kspc, mc68x328fb_getcolreg, info);
    else if (fb_display[con].cmap.len) /* non default colormap? */
	fb_copy_cmap(&fb_display[con].cmap, cmap, kspc ? 0 : 2);
    else
	fb_copy_cmap(fb_default_cmap(1<<fb_display[con].var.bits_per_pixel),
		     cmap, kspc ? 0 : 2);
    return 0;
}

    /*
     *  Set the Colormap
     */

static int mc68x328fb_set_cmap(struct fb_cmap *cmap, int kspc, int con,
			struct fb_info *info)
{
    int err;

    if (!fb_display[con].cmap.len) {	/* no colormap allocated? */
	if ((err = fb_alloc_cmap(&fb_display[con].cmap,
			      1<<fb_display[con].var.bits_per_pixel, 0)))
	    return err;
    }
    if (con == currcon)			/* current console? */
	return fb_set_cmap(cmap, kspc, mc68x328fb_setcolreg, info);
    else
	fb_copy_cmap(cmap, &fb_display[con].cmap, kspc ? 0 : 1);
    return 0;
}


int __init mc68x328fb_setup(char *options)
{
    char *this_opt;

    fb_info.fontname[0] = '\0';

    if (!options || !*options)
	return 0;

    while ((this_opt = strsep(&options, ",")) != NULL) {
	if (!strncmp(this_opt, "font:", 5))
	    strcpy(fb_info.fontname, this_opt+5);
    }
    return 0;
}


    /*
     *  Initialisation
     */

int __init mc68x328fb_init(void)
{
	/*
	 *  initialize the default mode from the LCD controller registers
	 */
	mc68x328fb_default.xres = LXMAX;
	mc68x328fb_default.yres = LYMAX+1;
	mc68x328fb_default.xres_virtual = mc68x328fb_default.xres;
	mc68x328fb_default.yres_virtual = mc68x328fb_default.yres;
	mc68x328fb_default.bits_per_pixel = 1 + (LPICF & 0x01);
	videomemory = LSSA;
	videomemorysize = (mc68x328fb_default.xres+7) / 8 *
		mc68x328fb_default.yres * mc68x328fb_default.bits_per_pixel;

    strcpy(fb_info.modename, mc68x328fb_name);
    fb_info.changevar = NULL;
    fb_info.node = -1;
    fb_info.fbops = &mc68x328fb_ops;
    fb_info.disp = &disp;
    fb_info.switch_con = &vfbcon_switch;
    fb_info.updatevar = &vfbcon_updatevar;
    fb_info.blank = &vfbcon_blank;
    fb_info.flags = FBINFO_FLAG_DEFAULT;

    mc68x328fb_set_var(&mc68x328fb_default, -1, &fb_info);

    if (register_framebuffer(&fb_info) < 0) {
	return -EINVAL;
    }

    printk(KERN_INFO "fb%d: %s frame buffer device\n", GET_FB_IDX(fb_info.node),
		mc68x328fb_name);
	printk(KERN_INFO "fb%d: %dx%dx%d at 0x%08lx\n", GET_FB_IDX(fb_info.node),
		mc68x328fb_default.xres, mc68x328fb_default.yres,
		1 << mc68x328fb_default.bits_per_pixel, videomemory);
    return 0;
}


static int vfbcon_switch(int con, struct fb_info *info)
{
    /* Do we have to save the colormap? */
    if (fb_display[currcon].cmap.len)
	fb_get_cmap(&fb_display[currcon].cmap, 1, mc68x328fb_getcolreg, info);

    currcon = con;
    /* Install new colormap */
    do_install_cmap(con, info);
    return 0;
}

    /*
     *  Update the `var' structure (called by fbcon.c)
     */

static int vfbcon_updatevar(int con, struct fb_info *info)
{
    /* Nothing */
    return 0;
}

    /*
     *  Blank the display.
     */

static void vfbcon_blank(int blank, struct fb_info *info)
{
    /* Nothing */
}

static u_long get_line_length(int xres_virtual, int bpp)
{
    u_long length;
    
    length = xres_virtual*bpp;
    length = (length+31)&-32;
    length >>= 3;
    return(length);
}

static void mc68x328fb_encode_fix(struct fb_fix_screeninfo *fix,
			   struct fb_var_screeninfo *var)
{
    memset(fix, 0, sizeof(struct fb_fix_screeninfo));
    strcpy(fix->id, mc68x328fb_name);
    fix->smem_start = videomemory;
    fix->smem_len = videomemorysize;
    fix->type = FB_TYPE_PACKED_PIXELS;
    fix->type_aux = 0;
    switch (var->bits_per_pixel) {
	case 1:
	    fix->visual = MC68X328FB_MONO_VISUAL;
	    break;
	case 2:
	case 4:
	case 8:
	    fix->visual = FB_VISUAL_PSEUDOCOLOR;
	    break;
	case 16:
	case 24:
	case 32:
	    fix->visual = FB_VISUAL_TRUECOLOR;
	    break;
    }
    fix->ywrapstep = 1;
    fix->xpanstep = 1;
    fix->ypanstep = 1;
    fix->line_length = get_line_length(var->xres_virtual, var->bits_per_pixel);
}

static void set_color_bitfields(struct fb_var_screeninfo *var)
{
    switch (var->bits_per_pixel) {
	case 1:
	case 8:
	    var->red.offset = 0;
	    var->red.length = 8;
	    var->green.offset = 0;
	    var->green.length = 8;
	    var->blue.offset = 0;
	    var->blue.length = 8;
	    var->transp.offset = 0;
	    var->transp.length = 0;
	    break;
	case 16:	/* RGB 565 */
	    var->red.offset = 0;
	    var->red.length = 5;
	    var->green.offset = 5;
	    var->green.length = 6;
	    var->blue.offset = 11;
	    var->blue.length = 5;
	    var->transp.offset = 0;
	    var->transp.length = 0;
	    break;
	case 24:	/* RGB 888 */
	    var->red.offset = 0;
	    var->red.length = 8;
	    var->green.offset = 8;
	    var->green.length = 8;
	    var->blue.offset = 16;
	    var->blue.length = 8;
	    var->transp.offset = 0;
	    var->transp.length = 0;
	    break;
	case 32:	/* RGBA 8888 */
	    var->red.offset = 0;
	    var->red.length = 8;
	    var->green.offset = 8;
	    var->green.length = 8;
	    var->blue.offset = 16;
	    var->blue.length = 8;
	    var->transp.offset = 24;
	    var->transp.length = 8;
	    break;
    }
    var->red.msb_right = 0;
    var->green.msb_right = 0;
    var->blue.msb_right = 0;
    var->transp.msb_right = 0;
}


    /*
     *  Read a single color register and split it into
     *  colors/transparent. Return != 0 for invalid regno.
     */

static int mc68x328fb_getcolreg(u_int regno, u_int *red, u_int *green, u_int *blue,
                         u_int *transp, struct fb_info *info)
{
    if (regno > 255)
	return 1;
    *red = (palette[regno].red<<8) | palette[regno].red;
    *green = (palette[regno].green<<8) | palette[regno].green;
    *blue = (palette[regno].blue<<8) | palette[regno].blue;
    *transp = 0;
    return 0;
}


    /*
     *  Set a single color register. The values supplied are already
     *  rounded down to the hardware's capabilities (according to the
     *  entries in the var structure). Return != 0 for invalid regno.
     */

static int mc68x328fb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
                         u_int transp, struct fb_info *info)
{
    if (regno > 255)
	return 1;
    red >>= 8;
    green >>= 8;
    blue >>= 8;
    palette[regno].red = red;
    palette[regno].green = green;
    palette[regno].blue = blue;
    return 0;
}


static void do_install_cmap(int con, struct fb_info *info)
{
    if (con != currcon)
	return;
    if (fb_display[con].cmap.len)
	fb_set_cmap(&fb_display[con].cmap, 1, mc68x328fb_setcolreg, info);
    else
	fb_set_cmap(fb_default_cmap(1<<fb_display[con].var.bits_per_pixel), 1,
		    mc68x328fb_setcolreg, info);
}


#ifdef MODULE
MODULE_LICENSE("GPL");

int init_module(void)
{
    return mc68x328fb_init();
}

void cleanup_module(void)
{
    unregister_framebuffer(&fb_info);
}

#endif /* MODULE */