/* drivers/video/s1d13xxxfb.c
 *
 * (c) 2004 Simtec Electronics
 * (c) 2005 Thibaut VARENE <varenet@parisc-linux.org>
 * (c) 2009 Kristoffer Ericson <kristoffer.ericson@gmail.com>
 *
 * Driver for Epson S1D13xxx series framebuffer chips
 *
 * Adapted from
 *  linux/drivers/video/skeletonfb.c
 *  linux/drivers/video/epson1355fb.c
 *  linux/drivers/video/epson/s1d13xxxfb.c (2.4 driver by Epson)
 *
 * TODO: - handle dual screen display (CRT and LCD at the same time).
 *       - check_var(), mode change, etc.
 *       - probably not SMP safe :)
 *       - support all bitblt operations on all cards
 *
 * 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/module.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/fb.h>
#include <linux/spinlock_types.h>
#include <linux/spinlock.h>
#include <linux/slab.h>

#include <asm/io.h>

#include <video/s1d13xxxfb.h>

#define PFX     "s1d13xxxfb: "
#define BLIT    "s1d13xxxfb_bitblt: "

/*
 * set this to enable debugging on general functions
 */
#if 0
#define dbg(fmt, args...) do { printk(KERN_INFO fmt, ## args); } while(0)
#else
#define dbg(fmt, args...) do { } while (0)
#endif

/*
 * set this to enable debugging on 2D acceleration
 */
#if 0
#define dbg_blit(fmt, args...) do { printk(KERN_INFO BLIT fmt, ## args); } while (0)
#else
#define dbg_blit(fmt, args...) do { } while (0)
#endif

/*
 * we make sure only one bitblt operation is running
 */
static DEFINE_SPINLOCK(s1d13xxxfb_bitblt_lock);

/*
 * list of card production ids
 */
static const int s1d13xxxfb_prod_ids[] = {
        S1D13505_PROD_ID,
        S1D13506_PROD_ID,
        S1D13806_PROD_ID,
};

/*
 * List of card strings
 */
static const char *s1d13xxxfb_prod_names[] = {
        "S1D13505",
        "S1D13506",
        "S1D13806",
};

/*
 * here we define the default struct fb_fix_screeninfo
 */
static struct fb_fix_screeninfo s1d13xxxfb_fix = {
        .id             = S1D_FBID,
        .type           = FB_TYPE_PACKED_PIXELS,
        .visual         = FB_VISUAL_PSEUDOCOLOR,
        .xpanstep       = 0,
        .ypanstep       = 1,
        .ywrapstep      = 0,
        .accel          = FB_ACCEL_NONE,
};

static inline u8
s1d13xxxfb_readreg(struct s1d13xxxfb_par *par, u16 regno)
{
#if defined(CONFIG_PLAT_M32700UT) || defined(CONFIG_PLAT_OPSPUT) || defined(CONFIG_PLAT_MAPPI3)
        regno=((regno & 1) ? (regno & ~1L) : (regno + 1));
#endif
        return readb(par->regs + regno);
}

static inline void
s1d13xxxfb_writereg(struct s1d13xxxfb_par *par, u16 regno, u8 value)
{
#if defined(CONFIG_PLAT_M32700UT) || defined(CONFIG_PLAT_OPSPUT) || defined(CONFIG_PLAT_MAPPI3)
        regno=((regno & 1) ? (regno & ~1L) : (regno + 1));
#endif
        writeb(value, par->regs + regno);
}

static inline void
s1d13xxxfb_runinit(struct s1d13xxxfb_par *par,
                        const struct s1d13xxxfb_regval *initregs,
                        const unsigned int size)
{
        int i;

        for (i = 0; i < size; i++) {
                if ((initregs[i].addr == S1DREG_DELAYOFF) ||
                                (initregs[i].addr == S1DREG_DELAYON))
                        mdelay((int)initregs[i].value);
                else {
                        s1d13xxxfb_writereg(par, initregs[i].addr, initregs[i].value);
                }
        }

        /* make sure the hardware can cope with us */
        mdelay(1);
}

static inline void
lcd_enable(struct s1d13xxxfb_par *par, int enable)
{
        u8 mode = s1d13xxxfb_readreg(par, S1DREG_COM_DISP_MODE);

        if (enable)
                mode |= 0x01;
        else
                mode &= ~0x01;

        s1d13xxxfb_writereg(par, S1DREG_COM_DISP_MODE, mode);
}

static inline void
crt_enable(struct s1d13xxxfb_par *par, int enable)
{
        u8 mode = s1d13xxxfb_readreg(par, S1DREG_COM_DISP_MODE);

        if (enable)
                mode |= 0x02;
        else
                mode &= ~0x02;

        s1d13xxxfb_writereg(par, S1DREG_COM_DISP_MODE, mode);
}


/*************************************************************
 framebuffer control functions
 *************************************************************/
static inline void
s1d13xxxfb_setup_pseudocolour(struct fb_info *info)
{
        info->fix.visual = FB_VISUAL_PSEUDOCOLOR;

        info->var.red.length = 4;
        info->var.green.length = 4;
        info->var.blue.length = 4;
}

static inline void
s1d13xxxfb_setup_truecolour(struct fb_info *info)
{
        info->fix.visual = FB_VISUAL_TRUECOLOR;
        info->var.bits_per_pixel = 16;

        info->var.red.length = 5;
        info->var.red.offset = 11;

        info->var.green.length = 6;
        info->var.green.offset = 5;

        info->var.blue.length = 5;
        info->var.blue.offset = 0;
}

/**
 *      s1d13xxxfb_set_par - Alters the hardware state.
 *      @info: frame buffer structure
 *
 *      Using the fb_var_screeninfo in fb_info we set the depth of the
 *      framebuffer. This function alters the par AND the
 *      fb_fix_screeninfo stored in fb_info. It doesn't not alter var in
 *      fb_info since we are using that data. This means we depend on the
 *      data in var inside fb_info to be supported by the hardware.
 *      xxxfb_check_var is always called before xxxfb_set_par to ensure this.
 *
 *      XXX TODO: write proper s1d13xxxfb_check_var(), without which that
 *      function is quite useless.
 */
static int
s1d13xxxfb_set_par(struct fb_info *info)
{
        struct s1d13xxxfb_par *s1dfb = info->par;
        unsigned int val;

        dbg("s1d13xxxfb_set_par: bpp=%d\n", info->var.bits_per_pixel);

        if ((s1dfb->display & 0x01))    /* LCD */
                val = s1d13xxxfb_readreg(s1dfb, S1DREG_LCD_DISP_MODE);   /* read colour control */
        else    /* CRT */
                val = s1d13xxxfb_readreg(s1dfb, S1DREG_CRT_DISP_MODE);   /* read colour control */

        val &= ~0x07;

        switch (info->var.bits_per_pixel) {
                case 4:
                        dbg("pseudo colour 4\n");
                        s1d13xxxfb_setup_pseudocolour(info);
                        val |= 2;
                        break;
                case 8:
                        dbg("pseudo colour 8\n");
                        s1d13xxxfb_setup_pseudocolour(info);
                        val |= 3;
                        break;
                case 16:
                        dbg("true colour\n");
                        s1d13xxxfb_setup_truecolour(info);
                        val |= 5;
                        break;

                default:
                        dbg("bpp not supported!\n");
                        return -EINVAL;
        }

        dbg("writing %02x to display mode register\n", val);

        if ((s1dfb->display & 0x01))    /* LCD */
                s1d13xxxfb_writereg(s1dfb, S1DREG_LCD_DISP_MODE, val);
        else    /* CRT */
                s1d13xxxfb_writereg(s1dfb, S1DREG_CRT_DISP_MODE, val);

        info->fix.line_length  = info->var.xres * info->var.bits_per_pixel;
        info->fix.line_length /= 8;

        dbg("setting line_length to %d\n", info->fix.line_length);

        dbg("done setup\n");

        return 0;
}

/**
 *      s1d13xxxfb_setcolreg - sets a color register.
 *      @regno: Which register in the CLUT we are programming
 *      @red: The red value which can be up to 16 bits wide
 *      @green: The green value which can be up to 16 bits wide
 *      @blue:  The blue value which can be up to 16 bits wide.
 *      @transp: If supported the alpha value which can be up to 16 bits wide.
 *      @info: frame buffer info structure
 *
 *      Returns negative errno on error, or zero on success.
 */
static int
s1d13xxxfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
                        u_int transp, struct fb_info *info)
{
        struct s1d13xxxfb_par *s1dfb = info->par;
        unsigned int pseudo_val;

        if (regno >= S1D_PALETTE_SIZE)
                return -EINVAL;

        dbg("s1d13xxxfb_setcolreg: %d: rgb=%d,%d,%d, tr=%d\n",
                    regno, red, green, blue, transp);

        if (info->var.grayscale)
                red = green = blue = (19595*red + 38470*green + 7471*blue) >> 16;

        switch (info->fix.visual) {
                case FB_VISUAL_TRUECOLOR:
                        if (regno >= 16)
                                return -EINVAL;

                        /* deal with creating pseudo-palette entries */

                        pseudo_val  = (red   >> 11) << info->var.red.offset;
                        pseudo_val |= (green >> 10) << info->var.green.offset;
                        pseudo_val |= (blue  >> 11) << info->var.blue.offset;

                        dbg("s1d13xxxfb_setcolreg: pseudo %d, val %08x\n",
                                    regno, pseudo_val);

#if defined(CONFIG_PLAT_MAPPI)
                        ((u32 *)info->pseudo_palette)[regno] = cpu_to_le16(pseudo_val);
#else
                        ((u32 *)info->pseudo_palette)[regno] = pseudo_val;
#endif

                        break;
                case FB_VISUAL_PSEUDOCOLOR:
                        s1d13xxxfb_writereg(s1dfb, S1DREG_LKUP_ADDR, regno);
                        s1d13xxxfb_writereg(s1dfb, S1DREG_LKUP_DATA, red);
                        s1d13xxxfb_writereg(s1dfb, S1DREG_LKUP_DATA, green);
                        s1d13xxxfb_writereg(s1dfb, S1DREG_LKUP_DATA, blue);

                        break;
                default:
                        return -ENOSYS;
        }

        dbg("s1d13xxxfb_setcolreg: done\n");

        return 0;
}

/**
 *      s1d13xxxfb_blank - blanks the display.
 *      @blank_mode: the blank mode we want.
 *      @info: frame buffer structure that represents a single frame buffer
 *
 *      Blank the screen if blank_mode != 0, else unblank. Return 0 if
 *      blanking succeeded, != 0 if un-/blanking failed due to e.g. a
 *      video mode which doesn't support it. Implements VESA suspend
 *      and powerdown modes on hardware that supports disabling hsync/vsync:
 *      blank_mode == 2: suspend vsync
 *      blank_mode == 3: suspend hsync
 *      blank_mode == 4: powerdown
 *
 *      Returns negative errno on error, or zero on success.
 */
static int
s1d13xxxfb_blank(int blank_mode, struct fb_info *info)
{
        struct s1d13xxxfb_par *par = info->par;

        dbg("s1d13xxxfb_blank: blank=%d, info=%p\n", blank_mode, info);

        switch (blank_mode) {
                case FB_BLANK_UNBLANK:
                case FB_BLANK_NORMAL:
                        if ((par->display & 0x01) != 0)
                                lcd_enable(par, 1);
                        if ((par->display & 0x02) != 0)
                                crt_enable(par, 1);
                        break;
                case FB_BLANK_VSYNC_SUSPEND:
                case FB_BLANK_HSYNC_SUSPEND:
                        break;
                case FB_BLANK_POWERDOWN:
                        lcd_enable(par, 0);
                        crt_enable(par, 0);
                        break;
                default:
                        return -EINVAL;
        }

        /* let fbcon do a soft blank for us */
        return ((blank_mode == FB_BLANK_NORMAL) ? 1 : 0);
}

/**
 *      s1d13xxxfb_pan_display - Pans the display.
 *      @var: frame buffer variable screen structure
 *      @info: frame buffer structure that represents a single frame buffer
 *
 *      Pan (or wrap, depending on the `vmode' field) the display using the
 *      `yoffset' field of the `var' structure (`xoffset'  not yet supported).
 *      If the values don't fit, return -EINVAL.
 *
 *      Returns negative errno on error, or zero on success.
 */
static int
s1d13xxxfb_pan_display(struct fb_var_screeninfo *var, struct fb_info *info)
{
        struct s1d13xxxfb_par *par = info->par;
        u32 start;

        if (var->xoffset != 0)  /* not yet ... */
                return -EINVAL;

        if (var->yoffset + info->var.yres > info->var.yres_virtual)
                return -EINVAL;

        start = (info->fix.line_length >> 1) * var->yoffset;

        if ((par->display & 0x01)) {
                /* LCD */
                s1d13xxxfb_writereg(par, S1DREG_LCD_DISP_START0, (start & 0xff));
                s1d13xxxfb_writereg(par, S1DREG_LCD_DISP_START1, ((start >> 8) & 0xff));
                s1d13xxxfb_writereg(par, S1DREG_LCD_DISP_START2, ((start >> 16) & 0x0f));
        } else {
                /* CRT */
                s1d13xxxfb_writereg(par, S1DREG_CRT_DISP_START0, (start & 0xff));
                s1d13xxxfb_writereg(par, S1DREG_CRT_DISP_START1, ((start >> 8) & 0xff));
                s1d13xxxfb_writereg(par, S1DREG_CRT_DISP_START2, ((start >> 16) & 0x0f));
        }

        return 0;
}

/************************************************************
 functions to handle bitblt acceleration
 ************************************************************/

/**
 *      bltbit_wait_bitclear - waits for change in register value
 *      @info : frambuffer structure
 *      @bit  : value currently in register
 *      @timeout : ...
 *
 *      waits until value changes FROM bit
 *
 */
static u8
bltbit_wait_bitclear(struct fb_info *info, u8 bit, int timeout)
{
        while (s1d13xxxfb_readreg(info->par, S1DREG_BBLT_CTL0) & bit) {
                udelay(10);
                if (!--timeout) {
                        dbg_blit("wait_bitclear timeout\n");
                        break;
                }
        }

        return timeout;
}

/*
 *      s1d13xxxfb_bitblt_copyarea - accelerated copyarea function
 *      @info : framebuffer structure
 *      @area : fb_copyarea structure
 *
 *      supports (atleast) S1D13506
 *
 */
static void
s1d13xxxfb_bitblt_copyarea(struct fb_info *info, const struct fb_copyarea *area)
{
        u32 dst, src;
        u32 stride;
        u16 reverse = 0;
        u16 sx = area->sx, sy = area->sy;
        u16 dx = area->dx, dy = area->dy;
        u16 width = area->width, height = area->height;
        u16 bpp;

        spin_lock(&s1d13xxxfb_bitblt_lock);

        /* bytes per xres line */
        bpp = (info->var.bits_per_pixel >> 3);
        stride = bpp * info->var.xres;

        /* reverse, calculate the last pixel in rectangle */
        if ((dy > sy) || ((dy == sy) && (dx >= sx))) {
                dst = (((dy + height - 1) * stride) + (bpp * (dx + width - 1)));
                src = (((sy + height - 1) * stride) + (bpp * (sx + width - 1)));
                reverse = 1;
        /* not reverse, calculate the first pixel in rectangle */
        } else { /* (y * xres) + (bpp * x) */
                dst = (dy * stride) + (bpp * dx);
                src = (sy * stride) + (bpp * sx);
        }

        /* set source address */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_SRC_START0, (src & 0xff));
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_SRC_START1, (src >> 8) & 0x00ff);
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_SRC_START2, (src >> 16) & 0x00ff);

        /* set destination address */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_DST_START0, (dst & 0xff));
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_DST_START1, (dst >> 8) & 0x00ff);
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_DST_START2, (dst >> 16) & 0x00ff);

        /* program height and width */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_WIDTH0, (width & 0xff) - 1);
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_WIDTH1, (width >> 8));

        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_HEIGHT0, (height & 0xff) - 1);
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_HEIGHT1, (height >> 8));

        /* negative direction ROP */
        if (reverse == 1) {
                dbg_blit("(copyarea) negative rop\n");
                s1d13xxxfb_writereg(info->par, S1DREG_BBLT_OP, 0x03);
        } else /* positive direction ROP */ {
                s1d13xxxfb_writereg(info->par, S1DREG_BBLT_OP, 0x02);
                dbg_blit("(copyarea) positive rop\n");
        }

        /* set for rectangel mode and not linear */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_CTL0, 0x0);

        /* setup the bpp 1 = 16bpp, 0 = 8bpp*/
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_CTL1, (bpp >> 1));

        /* set words per xres */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_MEM_OFF0, (stride >> 1) & 0xff);
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_MEM_OFF1, (stride >> 9));

        dbg_blit("(copyarea) dx=%d, dy=%d\n", dx, dy);
        dbg_blit("(copyarea) sx=%d, sy=%d\n", sx, sy);
        dbg_blit("(copyarea) width=%d, height=%d\n", width - 1, height - 1);
        dbg_blit("(copyarea) stride=%d\n", stride);
        dbg_blit("(copyarea) bpp=%d=0x0%d, mem_offset1=%d, mem_offset2=%d\n", bpp, (bpp >> 1),
                (stride >> 1) & 0xff, stride >> 9);

        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_CC_EXP, 0x0c);

        /* initialize the engine */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_CTL0, 0x80);

        /* wait to complete */
        bltbit_wait_bitclear(info, 0x80, 8000);

        spin_unlock(&s1d13xxxfb_bitblt_lock);
}

/**
 *
 *      s1d13xxxfb_bitblt_solidfill - accelerated solidfill function
 *      @info : framebuffer structure
 *      @rect : fb_fillrect structure
 *
 *      supports (atleast 13506)
 *
 **/
static void
s1d13xxxfb_bitblt_solidfill(struct fb_info *info, const struct fb_fillrect *rect)
{
        u32 screen_stride, dest;
        u32 fg;
        u16 bpp = (info->var.bits_per_pixel >> 3);

        /* grab spinlock */
        spin_lock(&s1d13xxxfb_bitblt_lock);

        /* bytes per x width */
        screen_stride = (bpp * info->var.xres);

        /* bytes to starting point */
        dest = ((rect->dy * screen_stride) + (bpp * rect->dx));

        dbg_blit("(solidfill) dx=%d, dy=%d, stride=%d, dest=%d\n"
                 "(solidfill) : rect_width=%d, rect_height=%d\n",
                                rect->dx, rect->dy, screen_stride, dest,
                                rect->width - 1, rect->height - 1);

        dbg_blit("(solidfill) : xres=%d, yres=%d, bpp=%d\n",
                                info->var.xres, info->var.yres,
                                info->var.bits_per_pixel);
        dbg_blit("(solidfill) : rop=%d\n", rect->rop);

        /* We split the destination into the three registers */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_DST_START0, (dest & 0x00ff));
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_DST_START1, ((dest >> 8) & 0x00ff));
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_DST_START2, ((dest >> 16) & 0x00ff));

        /* give information regarding rectangel width */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_WIDTH0, ((rect->width) & 0x00ff) - 1);
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_WIDTH1, (rect->width >> 8));

        /* give information regarding rectangel height */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_HEIGHT0, ((rect->height) & 0x00ff) - 1);
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_HEIGHT1, (rect->height >> 8));

        if (info->fix.visual == FB_VISUAL_TRUECOLOR ||
                info->fix.visual == FB_VISUAL_DIRECTCOLOR) {
                fg = ((u32 *)info->pseudo_palette)[rect->color];
                dbg_blit("(solidfill) truecolor/directcolor\n");
                dbg_blit("(solidfill) pseudo_palette[%d] = %d\n", rect->color, fg);
        } else {
                fg = rect->color;
                dbg_blit("(solidfill) color = %d\n", rect->color);
        }

        /* set foreground color */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_FGC0, (fg & 0xff));
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_FGC1, (fg >> 8) & 0xff);

        /* set rectangual region of memory (rectangle and not linear) */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_CTL0, 0x0);

        /* set operation mode SOLID_FILL */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_OP, BBLT_SOLID_FILL);

        /* set bits per pixel (1 = 16bpp, 0 = 8bpp) */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_CTL1, (info->var.bits_per_pixel >> 4));

        /* set the memory offset for the bblt in word sizes */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_MEM_OFF0, (screen_stride >> 1) & 0x00ff);
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_MEM_OFF1, (screen_stride >> 9));

        /* and away we go.... */
        s1d13xxxfb_writereg(info->par, S1DREG_BBLT_CTL0, 0x80);

        /* wait until its done */
        bltbit_wait_bitclear(info, 0x80, 8000);

        /* let others play */
        spin_unlock(&s1d13xxxfb_bitblt_lock);
}

/* framebuffer information structures */
static struct fb_ops s1d13xxxfb_fbops = {
        .owner          = THIS_MODULE,
        .fb_set_par     = s1d13xxxfb_set_par,
        .fb_setcolreg   = s1d13xxxfb_setcolreg,
        .fb_blank       = s1d13xxxfb_blank,

        .fb_pan_display = s1d13xxxfb_pan_display,

        /* gets replaced at chip detection time */
        .fb_fillrect    = cfb_fillrect,
        .fb_copyarea    = cfb_copyarea,
        .fb_imageblit   = cfb_imageblit,
};

static int s1d13xxxfb_width_tab[2][4] = {
        {4, 8, 16, -1},
        {9, 12, 18, -1},
};

/**
 *      s1d13xxxfb_fetch_hw_state - Configure the framebuffer according to
 *      hardware setup.
 *      @info: frame buffer structure
 *
 *      We setup the framebuffer structures according to the current
 *      hardware setup. On some machines, the BIOS will have filled
 *      the chip registers with such info, on others, these values will
 *      have been written in some init procedure. In any case, the
 *      software values needs to match the hardware ones. This is what
 *      this function ensures.
 *
 *      Note: some of the hardcoded values here might need some love to
 *      work on various chips, and might need to no longer be hardcoded.
 */
static void s1d13xxxfb_fetch_hw_state(struct fb_info *info)
{
        struct fb_var_screeninfo *var = &info->var;
        struct fb_fix_screeninfo *fix = &info->fix;
        struct s1d13xxxfb_par *par = info->par;
        u8 panel, display;
        u16 offset;
        u32 xres, yres;
        u32 xres_virtual, yres_virtual;
        int bpp, lcd_bpp;
        int is_color, is_dual, is_tft;
        int lcd_enabled, crt_enabled;

        fix->type = FB_TYPE_PACKED_PIXELS;

        /* general info */
        par->display = s1d13xxxfb_readreg(par, S1DREG_COM_DISP_MODE);
        crt_enabled = (par->display & 0x02) != 0;
        lcd_enabled = (par->display & 0x01) != 0;

        if (lcd_enabled && crt_enabled)
                printk(KERN_WARNING PFX "Warning: LCD and CRT detected, using LCD\n");

        if (lcd_enabled)
                display = s1d13xxxfb_readreg(par, S1DREG_LCD_DISP_MODE);
        else    /* CRT */
                display = s1d13xxxfb_readreg(par, S1DREG_CRT_DISP_MODE);

        bpp = display & 0x07;

        switch (bpp) {
                case 2: /* 4 bpp */
                case 3: /* 8 bpp */
                        var->bits_per_pixel = 8;
                        var->red.offset = var->green.offset = var->blue.offset = 0;
                        var->red.length = var->green.length = var->blue.length = 8;
                        break;
                case 5: /* 16 bpp */
                        s1d13xxxfb_setup_truecolour(info);
                        break;
                default:
                        dbg("bpp: %i\n", bpp);
        }
        fb_alloc_cmap(&info->cmap, 256, 0);

        /* LCD info */
        panel = s1d13xxxfb_readreg(par, S1DREG_PANEL_TYPE);
        is_color = (panel & 0x04) != 0;
        is_dual = (panel & 0x02) != 0;
        is_tft = (panel & 0x01) != 0;
        lcd_bpp = s1d13xxxfb_width_tab[is_tft][(panel >> 4) & 3];

        if (lcd_enabled) {
                xres = (s1d13xxxfb_readreg(par, S1DREG_LCD_DISP_HWIDTH) + 1) * 8;
                yres = (s1d13xxxfb_readreg(par, S1DREG_LCD_DISP_VHEIGHT0) +
                        ((s1d13xxxfb_readreg(par, S1DREG_LCD_DISP_VHEIGHT1) & 0x03) << 8) + 1);

                offset = (s1d13xxxfb_readreg(par, S1DREG_LCD_MEM_OFF0) +
                        ((s1d13xxxfb_readreg(par, S1DREG_LCD_MEM_OFF1) & 0x7) << 8));
        } else { /* crt */
                xres = (s1d13xxxfb_readreg(par, S1DREG_CRT_DISP_HWIDTH) + 1) * 8;
                yres = (s1d13xxxfb_readreg(par, S1DREG_CRT_DISP_VHEIGHT0) +
                        ((s1d13xxxfb_readreg(par, S1DREG_CRT_DISP_VHEIGHT1) & 0x03) << 8) + 1);

                offset = (s1d13xxxfb_readreg(par, S1DREG_CRT_MEM_OFF0) +
                        ((s1d13xxxfb_readreg(par, S1DREG_CRT_MEM_OFF1) & 0x7) << 8));
        }
        xres_virtual = offset * 16 / var->bits_per_pixel;
        yres_virtual = fix->smem_len / (offset * 2);

        var->xres               = xres;
        var->yres               = yres;
        var->xres_virtual       = xres_virtual;
        var->yres_virtual       = yres_virtual;
        var->xoffset            = var->yoffset = 0;

        fix->line_length        = offset * 2;

        var->grayscale          = !is_color;

        var->activate           = FB_ACTIVATE_NOW;

        dbg(PFX "bpp=%d, lcd_bpp=%d, "
                "crt_enabled=%d, lcd_enabled=%d\n",
                var->bits_per_pixel, lcd_bpp, crt_enabled, lcd_enabled);
        dbg(PFX "xres=%d, yres=%d, vxres=%d, vyres=%d "
                "is_color=%d, is_dual=%d, is_tft=%d\n",
                xres, yres, xres_virtual, yres_virtual, is_color, is_dual, is_tft);
}


static int
s1d13xxxfb_remove(struct platform_device *pdev)
{
        struct fb_info *info = platform_get_drvdata(pdev);
        struct s1d13xxxfb_par *par = NULL;

        if (info) {
                par = info->par;
                if (par && par->regs) {
                        /* disable output & enable powersave */
                        s1d13xxxfb_writereg(par, S1DREG_COM_DISP_MODE, 0x00);
                        s1d13xxxfb_writereg(par, S1DREG_PS_CNF, 0x11);
                        iounmap(par->regs);
                }

                fb_dealloc_cmap(&info->cmap);

                if (info->screen_base)
                        iounmap(info->screen_base);

                framebuffer_release(info);
        }

        release_mem_region(pdev->resource[0].start,
                        pdev->resource[0].end - pdev->resource[0].start +1);
        release_mem_region(pdev->resource[1].start,
                        pdev->resource[1].end - pdev->resource[1].start +1);
        return 0;
}

static int s1d13xxxfb_probe(struct platform_device *pdev)
{
        struct s1d13xxxfb_par *default_par;
        struct fb_info *info;
        struct s1d13xxxfb_pdata *pdata = NULL;
        int ret = 0;
        int i;
        u8 revision, prod_id;

        dbg("probe called: device is %p\n", pdev);

        printk(KERN_INFO "Epson S1D13XXX FB Driver\n");

        /* enable platform-dependent hardware glue, if any */
        if (pdev->dev.platform_data)
                pdata = pdev->dev.platform_data;

        if (pdata && pdata->platform_init_video)
                pdata->platform_init_video();

        if (pdev->num_resources != 2) {
                dev_err(&pdev->dev, "invalid num_resources: %i\n",
                       pdev->num_resources);
                ret = -ENODEV;
                goto bail;
        }

        /* resource[0] is VRAM, resource[1] is registers */
        if (pdev->resource[0].flags != IORESOURCE_MEM
                        || pdev->resource[1].flags != IORESOURCE_MEM) {
                dev_err(&pdev->dev, "invalid resource type\n");
                ret = -ENODEV;
                goto bail;
        }

        if (!request_mem_region(pdev->resource[0].start,
                pdev->resource[0].end - pdev->resource[0].start +1, "s1d13xxxfb mem")) {
                dev_dbg(&pdev->dev, "request_mem_region failed\n");
                ret = -EBUSY;
                goto bail;
        }

        if (!request_mem_region(pdev->resource[1].start,
                pdev->resource[1].end - pdev->resource[1].start +1, "s1d13xxxfb regs")) {
                dev_dbg(&pdev->dev, "request_mem_region failed\n");
                ret = -EBUSY;
                goto bail;
        }

        info = framebuffer_alloc(sizeof(struct s1d13xxxfb_par) + sizeof(u32) * 256, &pdev->dev);
        if (!info) {
                ret = -ENOMEM;
                goto bail;
        }

        platform_set_drvdata(pdev, info);
        default_par = info->par;
        default_par->regs = ioremap_nocache(pdev->resource[1].start,
                        pdev->resource[1].end - pdev->resource[1].start +1);
        if (!default_par->regs) {
                printk(KERN_ERR PFX "unable to map registers\n");
                ret = -ENOMEM;
                goto bail;
        }
        info->pseudo_palette = default_par->pseudo_palette;

        info->screen_base = ioremap_nocache(pdev->resource[0].start,
                        pdev->resource[0].end - pdev->resource[0].start +1);

        if (!info->screen_base) {
                printk(KERN_ERR PFX "unable to map framebuffer\n");
                ret = -ENOMEM;
                goto bail;
        }

        /* production id is top 6 bits */
        prod_id = s1d13xxxfb_readreg(default_par, S1DREG_REV_CODE) >> 2;
        /* revision id is lower 2 bits */
        revision = s1d13xxxfb_readreg(default_par, S1DREG_REV_CODE) & 0x3;
        ret = -ENODEV;

        for (i = 0; i < ARRAY_SIZE(s1d13xxxfb_prod_ids); i++) {
                if (prod_id == s1d13xxxfb_prod_ids[i]) {
                        /* looks like we got it in our list */
                        default_par->prod_id = prod_id;
                        default_par->revision = revision;
                        ret = 0;
                        break;
                }
        }

        if (!ret) {
                printk(KERN_INFO PFX "chip production id %i = %s\n",
                        prod_id, s1d13xxxfb_prod_names[i]);
                printk(KERN_INFO PFX "chip revision %i\n", revision);
        } else {
                printk(KERN_INFO PFX
                        "unknown chip production id %i, revision %i\n",
                        prod_id, revision);
                printk(KERN_INFO PFX "please contact maintainer\n");
                goto bail;
        }

        info->fix = s1d13xxxfb_fix;
        info->fix.mmio_start = pdev->resource[1].start;
        info->fix.mmio_len = pdev->resource[1].end - pdev->resource[1].start + 1;
        info->fix.smem_start = pdev->resource[0].start;
        info->fix.smem_len = pdev->resource[0].end - pdev->resource[0].start + 1;

        printk(KERN_INFO PFX "regs mapped at 0x%p, fb %d KiB mapped at 0x%p\n",
               default_par->regs, info->fix.smem_len / 1024, info->screen_base);

        info->par = default_par;
        info->flags = FBINFO_DEFAULT | FBINFO_HWACCEL_YPAN;
        info->fbops = &s1d13xxxfb_fbops;

        switch(prod_id) {
        case S1D13506_PROD_ID:  /* activate acceleration */
                s1d13xxxfb_fbops.fb_fillrect = s1d13xxxfb_bitblt_solidfill;
                s1d13xxxfb_fbops.fb_copyarea = s1d13xxxfb_bitblt_copyarea;
                info->flags = FBINFO_DEFAULT | FBINFO_HWACCEL_YPAN |
                        FBINFO_HWACCEL_FILLRECT | FBINFO_HWACCEL_COPYAREA;
                break;
        default:
                break;
        }

        /* perform "manual" chip initialization, if needed */
        if (pdata && pdata->initregs)
                s1d13xxxfb_runinit(info->par, pdata->initregs, pdata->initregssize);

        s1d13xxxfb_fetch_hw_state(info);

        if (register_framebuffer(info) < 0) {
                ret = -EINVAL;
                goto bail;
        }

        printk(KERN_INFO "fb%d: %s frame buffer device\n",
               info->node, info->fix.id);

        return 0;

bail:
        s1d13xxxfb_remove(pdev);
        return ret;

}

#ifdef CONFIG_PM
static int s1d13xxxfb_suspend(struct platform_device *dev, pm_message_t state)
{
        struct fb_info *info = platform_get_drvdata(dev);
        struct s1d13xxxfb_par *s1dfb = info->par;
        struct s1d13xxxfb_pdata *pdata = NULL;

        /* disable display */
        lcd_enable(s1dfb, 0);
        crt_enable(s1dfb, 0);

        if (dev->dev.platform_data)
                pdata = dev->dev.platform_data;

#if 0
        if (!s1dfb->disp_save)
                s1dfb->disp_save = kmalloc(info->fix.smem_len, GFP_KERNEL);

        if (!s1dfb->disp_save) {
                printk(KERN_ERR PFX "no memory to save screen");
                return -ENOMEM;
        }

        memcpy_fromio(s1dfb->disp_save, info->screen_base, info->fix.smem_len);
#else
        s1dfb->disp_save = NULL;
#endif

        if (!s1dfb->regs_save)
                s1dfb->regs_save = kmalloc(info->fix.mmio_len, GFP_KERNEL);

        if (!s1dfb->regs_save) {
                printk(KERN_ERR PFX "no memory to save registers");
                return -ENOMEM;
        }

        /* backup all registers */
        memcpy_fromio(s1dfb->regs_save, s1dfb->regs, info->fix.mmio_len);

        /* now activate power save mode */
        s1d13xxxfb_writereg(s1dfb, S1DREG_PS_CNF, 0x11);

        if (pdata && pdata->platform_suspend_video)
                return pdata->platform_suspend_video();
        else
                return 0;
}

static int s1d13xxxfb_resume(struct platform_device *dev)
{
        struct fb_info *info = platform_get_drvdata(dev);
        struct s1d13xxxfb_par *s1dfb = info->par;
        struct s1d13xxxfb_pdata *pdata = NULL;

        /* awaken the chip */
        s1d13xxxfb_writereg(s1dfb, S1DREG_PS_CNF, 0x10);

        /* do not let go until SDRAM "wakes up" */
        while ((s1d13xxxfb_readreg(s1dfb, S1DREG_PS_STATUS) & 0x01))
                udelay(10);

        if (dev->dev.platform_data)
                pdata = dev->dev.platform_data;

        if (s1dfb->regs_save) {
                /* will write RO regs, *should* get away with it :) */
                memcpy_toio(s1dfb->regs, s1dfb->regs_save, info->fix.mmio_len);
                kfree(s1dfb->regs_save);
        }

        if (s1dfb->disp_save) {
                memcpy_toio(info->screen_base, s1dfb->disp_save,
                                info->fix.smem_len);
                kfree(s1dfb->disp_save);        /* XXX kmalloc()'d when? */
        }

        if ((s1dfb->display & 0x01) != 0)
                lcd_enable(s1dfb, 1);
        if ((s1dfb->display & 0x02) != 0)
                crt_enable(s1dfb, 1);

        if (pdata && pdata->platform_resume_video)
                return pdata->platform_resume_video();
        else
                return 0;
}

#endif /* CONFIG_PM */

static struct platform_driver s1d13xxxfb_driver = {
        .probe          = s1d13xxxfb_probe,
        .remove         = s1d13xxxfb_remove,
#ifdef CONFIG_PM
        .suspend        = s1d13xxxfb_suspend,
        .resume         = s1d13xxxfb_resume,
#endif
        .driver         = {
                .name   = S1D_DEVICENAME,
        },
};


static int __init
s1d13xxxfb_init(void)
{

#ifndef MODULE
        if (fb_get_options("s1d13xxxfb", NULL))
                return -ENODEV;
#endif

        return platform_driver_register(&s1d13xxxfb_driver);
}


static void __exit
s1d13xxxfb_exit(void)
{
        platform_driver_unregister(&s1d13xxxfb_driver);
}

module_init(s1d13xxxfb_init);
module_exit(s1d13xxxfb_exit);


MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Framebuffer driver for S1D13xxx devices");
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, Thibaut VARENE <varenet@parisc-linux.org>");