linux/drivers/video/s3c2410fb.c

/*
 * linux/drivers/video/s3c2410fb.c
 *	Copyright (c) Arnaud Patard, Ben Dooks
 *
 * 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.
 *
 *	    S3C2410 LCD Controller Frame Buffer Driver
 *	    based on skeletonfb.c, sa1100fb.c and others
 *
 * ChangeLog
 * 2005-04-07: Arnaud Patard <arnaud.patard@rtp-net.org>
 *      - u32 state -> pm_message_t state
 *      - S3C2410_{VA,SZ}_LCD -> S3C24XX
 *
 * 2005-03-15: Arnaud Patard <arnaud.patard@rtp-net.org>
 *      - Removed the ioctl
 *      - use readl/writel instead of __raw_writel/__raw_readl
 *
 * 2004-12-04: Arnaud Patard <arnaud.patard@rtp-net.org>
 *      - Added the possibility to set on or off the
 *      debugging mesaages
 *      - Replaced 0 and 1 by on or off when reading the
 *      /sys files
 *
 * 2005-03-23: Ben Dooks <ben-linux@fluff.org>
 *	- added non 16bpp modes
 *	- updated platform information for range of x/y/bpp
 *	- add code to ensure palette is written correctly
 *	- add pixel clock divisor control
 *
 * 2004-11-11: Arnaud Patard <arnaud.patard@rtp-net.org>
 *	- Removed the use of currcon as it no more exist
 *	- Added LCD power sysfs interface
 *
 * 2004-11-03: Ben Dooks <ben-linux@fluff.org>
 *	- minor cleanups
 *	- add suspend/resume support
 *	- s3c2410fb_setcolreg() not valid in >8bpp modes
 *	- removed last CONFIG_FB_S3C2410_FIXED
 *	- ensure lcd controller stopped before cleanup
 *	- added sysfs interface for backlight power
 *	- added mask for gpio configuration
 *	- ensured IRQs disabled during GPIO configuration
 *	- disable TPAL before enabling video
 *
 * 2004-09-20: Arnaud Patard <arnaud.patard@rtp-net.org>
 *      - Suppress command line options
 *
 * 2004-09-15: Arnaud Patard <arnaud.patard@rtp-net.org>
 *	- code cleanup
 *
 * 2004-09-07: Arnaud Patard <arnaud.patard@rtp-net.org>
 *	- Renamed from h1940fb.c to s3c2410fb.c
 *	- Add support for different devices
 *	- Backlight support
 *
 * 2004-09-05: Herbert P<>tzl <herbert@13thfloor.at>
 *	- added clock (de-)allocation code
 *	- added fixem fbmem option
 *
 * 2004-07-27: Arnaud Patard <arnaud.patard@rtp-net.org>
 *	- code cleanup
 *	- added a forgotten return in h1940fb_init
 *
 * 2004-07-19: Herbert P<>tzl <herbert@13thfloor.at>
 *	- code cleanup and extended debugging
 *
 * 2004-07-15: Arnaud Patard <arnaud.patard@rtp-net.org>
 *	- First version
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/wait.h>
#include <linux/platform_device.h>
#include <linux/clk.h>

#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/div64.h>

#include <asm/mach/map.h>
#include <asm/arch/regs-lcd.h>
#include <asm/arch/regs-gpio.h>
#include <asm/arch/fb.h>

#ifdef CONFIG_PM
#include <linux/pm.h>
#endif

#include "s3c2410fb.h"

static struct s3c2410fb_mach_info *mach_info;

/* Debugging stuff */
#ifdef CONFIG_FB_S3C2410_DEBUG
static int debug	= 1;
#else
static int debug	= 0;
#endif

#define dprintk(msg...)	if (debug) { printk(KERN_DEBUG "s3c2410fb: " msg); }

/* useful functions */

/* s3c2410fb_set_lcdaddr
 *
 * initialise lcd controller address pointers
 */
static void s3c2410fb_set_lcdaddr(struct fb_info *info)
{
	unsigned long saddr1, saddr2, saddr3;
	int line_length = info->var.xres * info->var.bits_per_pixel;

	saddr1  = info->fix.smem_start >> 1;
	saddr2  = info->fix.smem_start;
	saddr2 += (line_length * info->var.yres) / 8;
	saddr2 >>= 1;

	saddr3 = S3C2410_OFFSIZE(0) |
		 S3C2410_PAGEWIDTH((line_length / 16) & 0x3ff);

	dprintk("LCDSADDR1 = 0x%08lx\n", saddr1);
	dprintk("LCDSADDR2 = 0x%08lx\n", saddr2);
	dprintk("LCDSADDR3 = 0x%08lx\n", saddr3);

	writel(saddr1, S3C2410_LCDSADDR1);
	writel(saddr2, S3C2410_LCDSADDR2);
	writel(saddr3, S3C2410_LCDSADDR3);
}

/* s3c2410fb_calc_pixclk()
 *
 * calculate divisor for clk->pixclk
 */
static unsigned int s3c2410fb_calc_pixclk(struct s3c2410fb_info *fbi,
					  unsigned long pixclk)
{
	unsigned long clk = clk_get_rate(fbi->clk);
	unsigned long long div;

	/* pixclk is in picoseoncds, our clock is in Hz
	 *
	 * Hz -> picoseconds is / 10^-12
	 */

	div = (unsigned long long)clk * pixclk;
	do_div(div, 1000000UL);
	do_div(div, 1000000UL);

	dprintk("pixclk %ld, divisor is %ld\n", pixclk, (long)div);
	return div;
}

/*
 *	s3c2410fb_check_var():
 *	Get the video params out of 'var'. If a value doesn't fit, round it up,
 *	if it's too big, return -EINVAL.
 *
 */
static int s3c2410fb_check_var(struct fb_var_screeninfo *var,
			       struct fb_info *info)
{
	struct s3c2410fb_info *fbi = info->par;
	struct s3c2410fb_mach_info *mach_info = fbi->mach_info;
	struct s3c2410fb_display *display = NULL;
	unsigned i;

	dprintk("check_var(var=%p, info=%p)\n", var, info);

	/* validate x/y resolution */

	for (i = 0; i < mach_info->num_displays; i++)
		if (var->yres == mach_info->displays[i].yres &&
		    var->xres == mach_info->displays[i].xres &&
		    var->bits_per_pixel == mach_info->displays[i].bpp) {
			display = mach_info->displays + i;
			fbi->current_display = i;
			break;
		}

	if (!display) {
		dprintk("wrong resolution or depth %dx%d at %d bpp\n",
			var->xres, var->yres, var->bits_per_pixel);
		return -EINVAL;
	}

	var->transp.offset = 0;
	var->transp.length = 0;
	/* set r/g/b positions */
	switch (var->bits_per_pixel) {
	case 1:
	case 2:
	case 4:
		var->red.offset	= 0;
		var->red.length	= var->bits_per_pixel;
		var->green	= var->red;
		var->blue	= var->red;
		break;
	case 8:
		if (display->type != S3C2410_LCDCON1_TFT) {
			/* 8 bpp 332 */
			var->red.length		= 3;
			var->red.offset		= 5;
			var->green.length	= 3;
			var->green.offset	= 2;
			var->blue.length	= 2;
			var->blue.offset	= 0;
		} else {
			var->red.offset		= 0;
			var->red.length		= 8;
			var->green		= var->red;
			var->blue		= var->red;
		}
		break;
	case 12:
		/* 12 bpp 444 */
		var->red.length		= 4;
		var->red.offset		= 8;
		var->green.length	= 4;
		var->green.offset	= 4;
		var->blue.length	= 4;
		var->blue.offset	= 0;
		break;

	default:
	case 16:
		if (display->regs.lcdcon5 & S3C2410_LCDCON5_FRM565) {
			/* 16 bpp, 565 format */
			var->red.offset		= 11;
			var->green.offset	= 5;
			var->blue.offset	= 0;
			var->red.length		= 5;
			var->green.length	= 6;
			var->blue.length	= 5;
		} else {
			/* 16 bpp, 5551 format */
			var->red.offset		= 11;
			var->green.offset	= 6;
			var->blue.offset	= 1;
			var->red.length		= 5;
			var->green.length	= 5;
			var->blue.length	= 5;
		}
		break;
	case 24:
		/* 24 bpp 888 */
		var->red.length		= 8;
		var->red.offset		= 16;
		var->green.length	= 8;
		var->green.offset	= 8;
		var->blue.length	= 8;
		var->blue.offset	= 0;
		break;


	}
	return 0;
}

/* s3c2410fb_activate_var
 *
 * activate (set) the controller from the given framebuffer
 * information
 */
static void s3c2410fb_activate_var(struct fb_info *info,
				   struct fb_var_screeninfo *var)
{
	struct s3c2410fb_info *fbi = info->par;
	struct s3c2410fb_mach_info *mach_info = fbi->mach_info;
	struct s3c2410fb_display *display = mach_info->displays +
					    fbi->current_display;
	int hs;

	fbi->regs.lcdcon1 &= ~S3C2410_LCDCON1_MODEMASK;
	fbi->regs.lcdcon1 &= ~S3C2410_LCDCON1_TFT;

	dprintk("%s: var->xres  = %d\n", __FUNCTION__, var->xres);
	dprintk("%s: var->yres  = %d\n", __FUNCTION__, var->yres);
	dprintk("%s: var->bpp   = %d\n", __FUNCTION__, var->bits_per_pixel);

	fbi->regs.lcdcon1 |= display->type;

	if (display->type == S3C2410_LCDCON1_TFT)
		switch (var->bits_per_pixel) {
		case 1:
			fbi->regs.lcdcon1 |= S3C2410_LCDCON1_TFT1BPP;
			break;
		case 2:
			fbi->regs.lcdcon1 |= S3C2410_LCDCON1_TFT2BPP;
			break;
		case 4:
			fbi->regs.lcdcon1 |= S3C2410_LCDCON1_TFT4BPP;
			break;
		case 8:
			fbi->regs.lcdcon1 |= S3C2410_LCDCON1_TFT8BPP;
			break;
		case 16:
			fbi->regs.lcdcon1 |= S3C2410_LCDCON1_TFT16BPP;
			break;

		default:
			/* invalid pixel depth */
			dev_err(fbi->dev, "invalid bpp %d\n",
				var->bits_per_pixel);
		}
	else
		switch (var->bits_per_pixel) {
		case 1:
			fbi->regs.lcdcon1 |= S3C2410_LCDCON1_STN1BPP;
			break;
		case 2:
			fbi->regs.lcdcon1 |= S3C2410_LCDCON1_STN2GREY;
			break;
		case 4:
			fbi->regs.lcdcon1 |= S3C2410_LCDCON1_STN4GREY;
			break;
		case 8:
			fbi->regs.lcdcon1 |= S3C2410_LCDCON1_STN8BPP;
			break;
		case 12:
			fbi->regs.lcdcon1 |= S3C2410_LCDCON1_STN12BPP;
			break;

		default:
			/* invalid pixel depth */
			dev_err(fbi->dev, "invalid bpp %d\n",
				var->bits_per_pixel);
		}

	/* check to see if we need to update sync/borders */

	if (!mach_info->fixed_syncs) {
		dprintk("setting vert: up=%d, low=%d, sync=%d\n",
			var->upper_margin, var->lower_margin, var->vsync_len);

		dprintk("setting horz: lft=%d, rt=%d, sync=%d\n",
			var->left_margin, var->right_margin, var->hsync_len);

		fbi->regs.lcdcon2 =
			S3C2410_LCDCON2_VBPD(var->upper_margin - 1) |
			S3C2410_LCDCON2_VFPD(var->lower_margin - 1) |
			S3C2410_LCDCON2_VSPW(var->vsync_len - 1);

		fbi->regs.lcdcon3 =
			S3C2410_LCDCON3_HBPD(var->right_margin - 1) |
			S3C2410_LCDCON3_HFPD(var->left_margin - 1);

		fbi->regs.lcdcon4 &= ~S3C2410_LCDCON4_HSPW(0xff);
		fbi->regs.lcdcon4 |=  S3C2410_LCDCON4_HSPW(var->hsync_len - 1);
	}

	/* update X/Y info */

	fbi->regs.lcdcon2 &= ~S3C2410_LCDCON2_LINEVAL(0x3ff);
	fbi->regs.lcdcon2 |=  S3C2410_LCDCON2_LINEVAL(var->yres - 1);

	switch (display->type) {
	case S3C2410_LCDCON1_DSCAN4:
	case S3C2410_LCDCON1_STN8:
		hs = var->xres / 8;
		break;
	case S3C2410_LCDCON1_STN4:
		hs = var->xres / 4;
		break;
	default:
	case S3C2410_LCDCON1_TFT:
		hs = var->xres;
		break;
	}

	/* Special cases : STN color displays */
	if (((fbi->regs.lcdcon1 & S3C2410_LCDCON1_MODEMASK) == S3C2410_LCDCON1_STN8BPP) ||
	    ((fbi->regs.lcdcon1 & S3C2410_LCDCON1_MODEMASK) == S3C2410_LCDCON1_STN12BPP))
		hs = hs * 3;

	fbi->regs.lcdcon3 &= ~S3C2410_LCDCON3_HOZVAL(0x7ff);
	fbi->regs.lcdcon3 |=  S3C2410_LCDCON3_HOZVAL(hs - 1);

	if (var->pixclock > 0) {
		int clkdiv = s3c2410fb_calc_pixclk(fbi, var->pixclock);

		if (display->type == S3C2410_LCDCON1_TFT) {
			clkdiv = (clkdiv / 2) - 1;
			if (clkdiv < 0)
				clkdiv = 0;
		} else {
			clkdiv = (clkdiv / 2);
			if (clkdiv < 2)
				clkdiv = 2;
		}

		fbi->regs.lcdcon1 &= ~S3C2410_LCDCON1_CLKVAL(0x3ff);
		fbi->regs.lcdcon1 |=  S3C2410_LCDCON1_CLKVAL(clkdiv);
	}

	/* write new registers */

	dprintk("new register set:\n");
	dprintk("lcdcon[1] = 0x%08lx\n", fbi->regs.lcdcon1);
	dprintk("lcdcon[2] = 0x%08lx\n", fbi->regs.lcdcon2);
	dprintk("lcdcon[3] = 0x%08lx\n", fbi->regs.lcdcon3);
	dprintk("lcdcon[4] = 0x%08lx\n", fbi->regs.lcdcon4);
	dprintk("lcdcon[5] = 0x%08lx\n", fbi->regs.lcdcon5);

	writel(fbi->regs.lcdcon1 & ~S3C2410_LCDCON1_ENVID, S3C2410_LCDCON1);
	writel(fbi->regs.lcdcon2, S3C2410_LCDCON2);
	writel(fbi->regs.lcdcon3, S3C2410_LCDCON3);
	writel(fbi->regs.lcdcon4, S3C2410_LCDCON4);
	writel(fbi->regs.lcdcon5, S3C2410_LCDCON5);

	/* set lcd address pointers */
	s3c2410fb_set_lcdaddr(info);

	writel(fbi->regs.lcdcon1, S3C2410_LCDCON1);
}

/*
 *      s3c2410fb_set_par - Alters the hardware state.
 *      @info: frame buffer structure that represents a single frame buffer
 *
 */
static int s3c2410fb_set_par(struct fb_info *info)
{
	struct fb_var_screeninfo *var = &info->var;

	switch (var->bits_per_pixel) {
	case 16:
		info->fix.visual = FB_VISUAL_TRUECOLOR;
		break;
	case 1:
		info->fix.visual = FB_VISUAL_MONO01;
		break;
	default:
		info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
		break;
	}

	info->fix.line_length = (var->width * var->bits_per_pixel) / 8;

	/* activate this new configuration */

	s3c2410fb_activate_var(info, var);
	return 0;
}

static void schedule_palette_update(struct s3c2410fb_info *fbi,
				    unsigned int regno, unsigned int val)
{
	unsigned long flags;
	unsigned long irqen;
	void __iomem *regs = fbi->io;

	local_irq_save(flags);

	fbi->palette_buffer[regno] = val;

	if (!fbi->palette_ready) {
		fbi->palette_ready = 1;

		/* enable IRQ */
		irqen = readl(regs + S3C2410_LCDINTMSK);
		irqen &= ~S3C2410_LCDINT_FRSYNC;
		writel(irqen, regs + S3C2410_LCDINTMSK);
	}

	local_irq_restore(flags);
}

/* from pxafb.c */
static inline unsigned int chan_to_field(unsigned int chan,
					 struct fb_bitfield *bf)
{
	chan &= 0xffff;
	chan >>= 16 - bf->length;
	return chan << bf->offset;
}

static int s3c2410fb_setcolreg(unsigned regno,
			       unsigned red, unsigned green, unsigned blue,
			       unsigned transp, struct fb_info *info)
{
	struct s3c2410fb_info *fbi = info->par;
	unsigned int val;

	/* dprintk("setcol: regno=%d, rgb=%d,%d,%d\n",
		   regno, red, green, blue); */

	switch (info->fix.visual) {
	case FB_VISUAL_TRUECOLOR:
		/* true-colour, use pseudo-palette */

		if (regno < 16) {
			u32 *pal = info->pseudo_palette;

			val  = chan_to_field(red,   &info->var.red);
			val |= chan_to_field(green, &info->var.green);
			val |= chan_to_field(blue,  &info->var.blue);

			pal[regno] = val;
		}
		break;

	case FB_VISUAL_PSEUDOCOLOR:
		if (regno < 256) {
			/* currently assume RGB 5-6-5 mode */

			val  = ((red   >>  0) & 0xf800);
			val |= ((green >>  5) & 0x07e0);
			val |= ((blue  >> 11) & 0x001f);

			writel(val, S3C2410_TFTPAL(regno));
			schedule_palette_update(fbi, regno, val);
		}

		break;

	default:
		return 1;	/* unknown type */
	}

	return 0;
}

/*
 *      s3c2410fb_blank
 *	@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 s3c2410fb_blank(int blank_mode, struct fb_info *info)
{
	dprintk("blank(mode=%d, info=%p)\n", blank_mode, info);

	if (mach_info == NULL)
		return -EINVAL;

	if (blank_mode == FB_BLANK_UNBLANK)
		writel(0x0, S3C2410_TPAL);
	else {
		dprintk("setting TPAL to output 0x000000\n");
		writel(S3C2410_TPAL_EN, S3C2410_TPAL);
	}

	return 0;
}

static int s3c2410fb_debug_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	return snprintf(buf, PAGE_SIZE, "%s\n", debug ? "on" : "off");
}
static int s3c2410fb_debug_store(struct device *dev,
				 struct device_attribute *attr,
				 const char *buf, size_t len)
{
	if (mach_info == NULL)
		return -EINVAL;

	if (len < 1)
		return -EINVAL;

	if (strnicmp(buf, "on", 2) == 0 ||
	    strnicmp(buf, "1", 1) == 0) {
		debug = 1;
		printk(KERN_DEBUG "s3c2410fb: Debug On");
	} else if (strnicmp(buf, "off", 3) == 0 ||
		   strnicmp(buf, "0", 1) == 0) {
		debug = 0;
		printk(KERN_DEBUG "s3c2410fb: Debug Off");
	} else {
		return -EINVAL;
	}

	return len;
}

static DEVICE_ATTR(debug, 0666, s3c2410fb_debug_show, s3c2410fb_debug_store);

static struct fb_ops s3c2410fb_ops = {
	.owner		= THIS_MODULE,
	.fb_check_var	= s3c2410fb_check_var,
	.fb_set_par	= s3c2410fb_set_par,
	.fb_blank	= s3c2410fb_blank,
	.fb_setcolreg	= s3c2410fb_setcolreg,
	.fb_fillrect	= cfb_fillrect,
	.fb_copyarea	= cfb_copyarea,
	.fb_imageblit	= cfb_imageblit,
};

/*
 * s3c2410fb_map_video_memory():
 *	Allocates the DRAM memory for the frame buffer.  This buffer is
 *	remapped into a non-cached, non-buffered, memory region to
 *	allow palette and pixel writes to occur without flushing the
 *	cache.  Once this area is remapped, all virtual memory
 *	access to the video memory should occur at the new region.
 */
static int __init s3c2410fb_map_video_memory(struct fb_info *info)
{
	struct s3c2410fb_info *fbi = info->par;

	dprintk("map_video_memory(fbi=%p)\n", fbi);

	fbi->map_size = PAGE_ALIGN(info->fix.smem_len + PAGE_SIZE);
	fbi->map_cpu  = dma_alloc_writecombine(fbi->dev, fbi->map_size,
					       &fbi->map_dma, GFP_KERNEL);

	fbi->map_size = info->fix.smem_len;

	if (fbi->map_cpu) {
		/* prevent initial garbage on screen */
		dprintk("map_video_memory: clear %p:%08x\n",
			fbi->map_cpu, fbi->map_size);
		memset(fbi->map_cpu, 0xf0, fbi->map_size);

		fbi->screen_dma		= fbi->map_dma;
		info->screen_base	= fbi->map_cpu;
		info->fix.smem_start	= fbi->screen_dma;

		dprintk("map_video_memory: dma=%08x cpu=%p size=%08x\n",
			fbi->map_dma, fbi->map_cpu, info->fix.smem_len);
	}

	return fbi->map_cpu ? 0 : -ENOMEM;
}

static inline void s3c2410fb_unmap_video_memory(struct s3c2410fb_info *fbi)
{
	dma_free_writecombine(fbi->dev, fbi->map_size, fbi->map_cpu,
			      fbi->map_dma);
}

static inline void modify_gpio(void __iomem *reg,
			       unsigned long set, unsigned long mask)
{
	unsigned long tmp;

	tmp = readl(reg) & ~mask;
	writel(tmp | set, reg);
}

/*
 * s3c2410fb_init_registers - Initialise all LCD-related registers
 */
static int s3c2410fb_init_registers(struct fb_info *info)
{
	struct s3c2410fb_info *fbi = info->par;
	unsigned long flags;
	void __iomem *regs = fbi->io;

	/* Initialise LCD with values from haret */

	local_irq_save(flags);

	/* modify the gpio(s) with interrupts set (bjd) */

	modify_gpio(S3C2410_GPCUP,  mach_info->gpcup,  mach_info->gpcup_mask);
	modify_gpio(S3C2410_GPCCON, mach_info->gpccon, mach_info->gpccon_mask);
	modify_gpio(S3C2410_GPDUP,  mach_info->gpdup,  mach_info->gpdup_mask);
	modify_gpio(S3C2410_GPDCON, mach_info->gpdcon, mach_info->gpdcon_mask);

	local_irq_restore(flags);

	writel(fbi->regs.lcdcon1, regs + S3C2410_LCDCON1);
	writel(fbi->regs.lcdcon2, regs + S3C2410_LCDCON2);
	writel(fbi->regs.lcdcon3, regs + S3C2410_LCDCON3);
	writel(fbi->regs.lcdcon4, regs + S3C2410_LCDCON4);
	writel(fbi->regs.lcdcon5, regs + S3C2410_LCDCON5);

	s3c2410fb_set_lcdaddr(info);

	dprintk("LPCSEL    = 0x%08lx\n", mach_info->lpcsel);
	writel(mach_info->lpcsel, regs + S3C2410_LPCSEL);

	dprintk("replacing TPAL %08x\n", readl(regs + S3C2410_TPAL));

	/* ensure temporary palette disabled */
	writel(0x00, regs + S3C2410_TPAL);

	/* Enable video by setting the ENVID bit to 1 */
	fbi->regs.lcdcon1 |= S3C2410_LCDCON1_ENVID;
	writel(fbi->regs.lcdcon1, regs + S3C2410_LCDCON1);
	return 0;
}

static void s3c2410fb_write_palette(struct s3c2410fb_info *fbi)
{
	unsigned int i;
	void __iomem *regs = fbi->io;

	fbi->palette_ready = 0;

	for (i = 0; i < 256; i++) {
		unsigned long ent = fbi->palette_buffer[i];
		if (ent == PALETTE_BUFF_CLEAR)
			continue;

		writel(ent, regs + S3C2410_TFTPAL(i));

		/* it seems the only way to know exactly
		 * if the palette wrote ok, is to check
		 * to see if the value verifies ok
		 */

		if (readw(regs + S3C2410_TFTPAL(i)) == ent)
			fbi->palette_buffer[i] = PALETTE_BUFF_CLEAR;
		else
			fbi->palette_ready = 1;   /* retry */
	}
}

static irqreturn_t s3c2410fb_irq(int irq, void *dev_id)
{
	struct s3c2410fb_info *fbi = dev_id;
	void __iomem *regs = fbi->io;
	unsigned long lcdirq = readl(regs + S3C2410_LCDINTPND);

	if (lcdirq & S3C2410_LCDINT_FRSYNC) {
		if (fbi->palette_ready)
			s3c2410fb_write_palette(fbi);

		writel(S3C2410_LCDINT_FRSYNC, regs + S3C2410_LCDINTPND);
		writel(S3C2410_LCDINT_FRSYNC, regs + S3C2410_LCDSRCPND);
	}

	return IRQ_HANDLED;
}

static char driver_name[] = "s3c2410fb";

static int __init s3c2410fb_probe(struct platform_device *pdev)
{
	struct s3c2410fb_info *info;
	struct s3c2410fb_display *display;
	struct fb_info *fbinfo;
	struct s3c2410fb_hw *mregs;
	struct resource *res;
	int ret;
	int irq;
	int i;
	int size;
	u32 lcdcon1;

	mach_info = pdev->dev.platform_data;
	if (mach_info == NULL) {
		dev_err(&pdev->dev,
			"no platform data for lcd, cannot attach\n");
		return -EINVAL;
	}

	display = mach_info->displays + mach_info->default_display;
	mregs = &display->regs;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(&pdev->dev, "no irq for device\n");
		return -ENOENT;
	}

	fbinfo = framebuffer_alloc(sizeof(struct s3c2410fb_info), &pdev->dev);
	if (!fbinfo)
		return -ENOMEM;

	info = fbinfo->par;
	info->dev = &pdev->dev;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (res == NULL) {
		dev_err(&pdev->dev, "failed to get memory registers\n");
		ret = -ENXIO;
		goto dealloc_fb;
	}

	size = (res->end - res->start) + 1;
	info->mem = request_mem_region(res->start, size, pdev->name);
	if (info->mem == NULL) {
		dev_err(&pdev->dev, "failed to get memory region\n");
		ret = -ENOENT;
		goto dealloc_fb;
	}

	info->io = ioremap(res->start, size);
	if (info->io == NULL) {
		dev_err(&pdev->dev, "ioremap() of registers failed\n");
		ret = -ENXIO;
		goto release_mem;
	}

	platform_set_drvdata(pdev, fbinfo);

	dprintk("devinit\n");

	strcpy(fbinfo->fix.id, driver_name);

	memcpy(&info->regs, &display->regs, sizeof(info->regs));

	/* Stop the video and unset ENVID if set */
	info->regs.lcdcon1 &= ~S3C2410_LCDCON1_ENVID;
	lcdcon1 = readl(info->io + S3C2410_LCDCON1);
	writel(lcdcon1 & ~S3C2410_LCDCON1_ENVID, info->io + S3C2410_LCDCON1);

	info->mach_info		    = pdev->dev.platform_data;
	info->current_display	    = mach_info->default_display;

	fbinfo->fix.type	    = FB_TYPE_PACKED_PIXELS;
	fbinfo->fix.type_aux	    = 0;
	fbinfo->fix.xpanstep	    = 0;
	fbinfo->fix.ypanstep	    = 0;
	fbinfo->fix.ywrapstep	    = 0;
	fbinfo->fix.accel	    = FB_ACCEL_NONE;

	fbinfo->var.nonstd	    = 0;
	fbinfo->var.activate	    = FB_ACTIVATE_NOW;
	fbinfo->var.height	    = display->height;
	fbinfo->var.width	    = display->width;
	fbinfo->var.accel_flags     = 0;
	fbinfo->var.vmode	    = FB_VMODE_NONINTERLACED;

	fbinfo->fbops		    = &s3c2410fb_ops;
	fbinfo->flags		    = FBINFO_FLAG_DEFAULT;
	fbinfo->pseudo_palette      = &info->pseudo_pal;

	fbinfo->var.xres	    = display->xres;
	fbinfo->var.xres_virtual    = display->xres;
	fbinfo->var.yres	    = display->yres;
	fbinfo->var.yres_virtual    = display->yres;
	fbinfo->var.bits_per_pixel  = display->bpp;

	fbinfo->var.upper_margin    =
				S3C2410_LCDCON2_GET_VBPD(mregs->lcdcon2) + 1;
	fbinfo->var.lower_margin    =
				S3C2410_LCDCON2_GET_VFPD(mregs->lcdcon2) + 1;
	fbinfo->var.vsync_len	    =
				S3C2410_LCDCON2_GET_VSPW(mregs->lcdcon2) + 1;

	fbinfo->var.left_margin	    =
				S3C2410_LCDCON3_GET_HFPD(mregs->lcdcon3) + 1;
	fbinfo->var.right_margin    =
				S3C2410_LCDCON3_GET_HBPD(mregs->lcdcon3) + 1;
	fbinfo->var.hsync_len	    =
				S3C2410_LCDCON4_GET_HSPW(mregs->lcdcon4) + 1;

	fbinfo->var.red.offset      = 11;
	fbinfo->var.green.offset    = 5;
	fbinfo->var.blue.offset     = 0;
	fbinfo->var.transp.offset   = 0;
	fbinfo->var.red.length      = 5;
	fbinfo->var.green.length    = 6;
	fbinfo->var.blue.length     = 5;
	fbinfo->var.transp.length   = 0;

	/* find maximum required memory size for display */
	for (i = 0; i < mach_info->num_displays; i++) {
		unsigned long smem_len = mach_info->displays[i].xres;

		smem_len *= mach_info->displays[i].yres;
		smem_len *= mach_info->displays[i].bpp;
		smem_len >>= 3;
		if (fbinfo->fix.smem_len < smem_len)
			fbinfo->fix.smem_len = smem_len;
	}

	for (i = 0; i < 256; i++)
		info->palette_buffer[i] = PALETTE_BUFF_CLEAR;

	ret = request_irq(irq, s3c2410fb_irq, IRQF_DISABLED, pdev->name, info);
	if (ret) {
		dev_err(&pdev->dev, "cannot get irq %d - err %d\n", irq, ret);
		ret = -EBUSY;
		goto release_regs;
	}

	info->clk = clk_get(NULL, "lcd");
	if (!info->clk || IS_ERR(info->clk)) {
		printk(KERN_ERR "failed to get lcd clock source\n");
		ret = -ENOENT;
		goto release_irq;
	}

	clk_enable(info->clk);
	dprintk("got and enabled clock\n");

	msleep(1);

	/* Initialize video memory */
	ret = s3c2410fb_map_video_memory(fbinfo);
	if (ret) {
		printk(KERN_ERR "Failed to allocate video RAM: %d\n", ret);
		ret = -ENOMEM;
		goto release_clock;
	}

	dprintk("got video memory\n");

	s3c2410fb_init_registers(fbinfo);

	s3c2410fb_check_var(&fbinfo->var, fbinfo);

	ret = register_framebuffer(fbinfo);
	if (ret < 0) {
		printk(KERN_ERR "Failed to register framebuffer device: %d\n",
			ret);
		goto free_video_memory;
	}

	/* create device files */
	device_create_file(&pdev->dev, &dev_attr_debug);

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

	return 0;

free_video_memory:
	s3c2410fb_unmap_video_memory(info);
release_clock:
	clk_disable(info->clk);
	clk_put(info->clk);
release_irq:
	free_irq(irq, info);
release_regs:
	iounmap(info->io);
release_mem:
	release_resource(info->mem);
	kfree(info->mem);
dealloc_fb:
	framebuffer_release(fbinfo);
	return ret;
}

/* s3c2410fb_stop_lcd
 *
 * shutdown the lcd controller
 */
static void s3c2410fb_stop_lcd(struct s3c2410fb_info *fbi)
{
	unsigned long flags;

	local_irq_save(flags);

	fbi->regs.lcdcon1 &= ~S3C2410_LCDCON1_ENVID;
	writel(fbi->regs.lcdcon1, fbi->io + S3C2410_LCDCON1);

	local_irq_restore(flags);
}

/*
 *  Cleanup
 */
static int s3c2410fb_remove(struct platform_device *pdev)
{
	struct fb_info *fbinfo = platform_get_drvdata(pdev);
	struct s3c2410fb_info *info = fbinfo->par;
	int irq;

	s3c2410fb_stop_lcd(info);
	msleep(1);

	s3c2410fb_unmap_video_memory(info);

	if (info->clk) {
		clk_disable(info->clk);
		clk_put(info->clk);
		info->clk = NULL;
	}

	irq = platform_get_irq(pdev, 0);
	free_irq(irq, info);

	release_resource(info->mem);
	kfree(info->mem);
	iounmap(info->io);
	unregister_framebuffer(fbinfo);

	return 0;
}

#ifdef CONFIG_PM

/* suspend and resume support for the lcd controller */
static int s3c2410fb_suspend(struct platform_device *dev, pm_message_t state)
{
	struct fb_info	   *fbinfo = platform_get_drvdata(dev);
	struct s3c2410fb_info *info = fbinfo->par;

	s3c2410fb_stop_lcd(info);

	/* sleep before disabling the clock, we need to ensure
	 * the LCD DMA engine is not going to get back on the bus
	 * before the clock goes off again (bjd) */

	msleep(1);
	clk_disable(info->clk);

	return 0;
}

static int s3c2410fb_resume(struct platform_device *dev)
{
	struct fb_info	   *fbinfo = platform_get_drvdata(dev);
	struct s3c2410fb_info *info = fbinfo->par;

	clk_enable(info->clk);
	msleep(1);

	s3c2410fb_init_registers(info);

	return 0;
}

#else
#define s3c2410fb_suspend NULL
#define s3c2410fb_resume  NULL
#endif

static struct platform_driver s3c2410fb_driver = {
	.probe		= s3c2410fb_probe,
	.remove		= s3c2410fb_remove,
	.suspend	= s3c2410fb_suspend,
	.resume		= s3c2410fb_resume,
	.driver		= {
		.name	= "s3c2410-lcd",
		.owner	= THIS_MODULE,
	},
};

int __devinit s3c2410fb_init(void)
{
	return platform_driver_register(&s3c2410fb_driver);
}

static void __exit s3c2410fb_cleanup(void)
{
	platform_driver_unregister(&s3c2410fb_driver);
}

module_init(s3c2410fb_init);
module_exit(s3c2410fb_cleanup);

MODULE_AUTHOR("Arnaud Patard <arnaud.patard@rtp-net.org>, "
	      "Ben Dooks <ben-linux@fluff.org>");
MODULE_DESCRIPTION("Framebuffer driver for the s3c2410");
MODULE_LICENSE("GPL");