drivers/video/mxsfb.c

/*
 * Copyright (C) 2010 Juergen Beisert, Pengutronix
 *
 * This code is based on:
 * Author: Vitaly Wool <vital@embeddedalley.com>
 *
 * Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
 * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#define DRIVER_NAME "mxsfb"

/**
 * @file
 * @brief LCDIF driver for i.MX23 and i.MX28
 *
 * The LCDIF support four modes of operation
 * - MPU interface (to drive smart displays) -> not supported yet
 * - VSYNC interface (like MPU interface plus Vsync) -> not supported yet
 * - Dotclock interface (to drive LC displays with RGB data and sync signals)
 * - DVI (to drive ITU-R BT656)  -> not supported yet
 *
 * This driver depends on a correct setup of the pins used for this purpose
 * (platform specific).
 *
 * For the developer: Don't forget to set the data bus width to the display
 * in the imx_fb_videomode structure. You will else end up with ugly colours.
 * If you fight against jitter you can vary the clock delay. This is a feature
 * of the i.MX28 and you can vary it between 2 ns ... 8 ns in 2 ns steps. Give
 * the required value in the imx_fb_videomode structure.
 */

#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <mach/mxsfb.h>

#define REG_SET	4
#define REG_CLR	8

#define LCDC_CTRL			0x00
#define LCDC_CTRL1			0x10
#define LCDC_V4_CTRL2			0x20
#define LCDC_V3_TRANSFER_COUNT		0x20
#define LCDC_V4_TRANSFER_COUNT		0x30
#define LCDC_V4_CUR_BUF			0x40
#define LCDC_V4_NEXT_BUF		0x50
#define LCDC_V3_CUR_BUF			0x30
#define LCDC_V3_NEXT_BUF		0x40
#define LCDC_TIMING			0x60
#define LCDC_VDCTRL0			0x70
#define LCDC_VDCTRL1			0x80
#define LCDC_VDCTRL2			0x90
#define LCDC_VDCTRL3			0xa0
#define LCDC_VDCTRL4			0xb0
#define LCDC_DVICTRL0			0xc0
#define LCDC_DVICTRL1			0xd0
#define LCDC_DVICTRL2			0xe0
#define LCDC_DVICTRL3			0xf0
#define LCDC_DVICTRL4			0x100
#define LCDC_V4_DATA			0x180
#define LCDC_V3_DATA			0x1b0
#define LCDC_V4_DEBUG0			0x1d0
#define LCDC_V3_DEBUG0			0x1f0

#define CTRL_SFTRST			(1 << 31)
#define CTRL_CLKGATE			(1 << 30)
#define CTRL_BYPASS_COUNT		(1 << 19)
#define CTRL_VSYNC_MODE			(1 << 18)
#define CTRL_DOTCLK_MODE		(1 << 17)
#define CTRL_DATA_SELECT		(1 << 16)
#define CTRL_SET_BUS_WIDTH(x)		(((x) & 0x3) << 10)
#define CTRL_GET_BUS_WIDTH(x)		(((x) >> 10) & 0x3)
#define CTRL_SET_WORD_LENGTH(x)		(((x) & 0x3) << 8)
#define CTRL_GET_WORD_LENGTH(x)		(((x) >> 8) & 0x3)
#define CTRL_MASTER			(1 << 5)
#define CTRL_DF16			(1 << 3)
#define CTRL_DF18			(1 << 2)
#define CTRL_DF24			(1 << 1)
#define CTRL_RUN			(1 << 0)

#define CTRL1_FIFO_CLEAR		(1 << 21)
#define CTRL1_SET_BYTE_PACKAGING(x)	(((x) & 0xf) << 16)
#define CTRL1_GET_BYTE_PACKAGING(x)	(((x) >> 16) & 0xf)

#define TRANSFER_COUNT_SET_VCOUNT(x)	(((x) & 0xffff) << 16)
#define TRANSFER_COUNT_GET_VCOUNT(x)	(((x) >> 16) & 0xffff)
#define TRANSFER_COUNT_SET_HCOUNT(x)	((x) & 0xffff)
#define TRANSFER_COUNT_GET_HCOUNT(x)	((x) & 0xffff)


#define VDCTRL0_ENABLE_PRESENT		(1 << 28)
#define VDCTRL0_VSYNC_ACT_HIGH		(1 << 27)
#define VDCTRL0_HSYNC_ACT_HIGH		(1 << 26)
#define VDCTRL0_DOTCLK_ACT_FAILING	(1 << 25)
#define VDCTRL0_ENABLE_ACT_HIGH		(1 << 24)
#define VDCTRL0_VSYNC_PERIOD_UNIT	(1 << 21)
#define VDCTRL0_VSYNC_PULSE_WIDTH_UNIT	(1 << 20)
#define VDCTRL0_HALF_LINE		(1 << 19)
#define VDCTRL0_HALF_LINE_MODE		(1 << 18)
#define VDCTRL0_SET_VSYNC_PULSE_WIDTH(x) ((x) & 0x3ffff)
#define VDCTRL0_GET_VSYNC_PULSE_WIDTH(x) ((x) & 0x3ffff)

#define VDCTRL2_SET_HSYNC_PERIOD(x)	((x) & 0x3ffff)
#define VDCTRL2_GET_HSYNC_PERIOD(x)	((x) & 0x3ffff)

#define VDCTRL3_MUX_SYNC_SIGNALS	(1 << 29)
#define VDCTRL3_VSYNC_ONLY		(1 << 28)
#define SET_HOR_WAIT_CNT(x)		(((x) & 0xfff) << 16)
#define GET_HOR_WAIT_CNT(x)		(((x) >> 16) & 0xfff)
#define SET_VERT_WAIT_CNT(x)		((x) & 0xffff)
#define GET_VERT_WAIT_CNT(x)		((x) & 0xffff)

#define VDCTRL4_SET_DOTCLK_DLY(x)	(((x) & 0x7) << 29) /* v4 only */
#define VDCTRL4_GET_DOTCLK_DLY(x)	(((x) >> 29) & 0x7) /* v4 only */
#define VDCTRL4_SYNC_SIGNALS_ON		(1 << 18)
#define SET_DOTCLK_H_VALID_DATA_CNT(x)	((x) & 0x3ffff)

#define DEBUG0_HSYNC			(1 < 26)
#define DEBUG0_VSYNC			(1 < 25)

#define MIN_XRES			120
#define MIN_YRES			120

#define RED 0
#define GREEN 1
#define BLUE 2
#define TRANSP 3

enum mxsfb_devtype {
	MXSFB_V3,
	MXSFB_V4,
};

/* CPU dependent register offsets */
struct mxsfb_devdata {
	unsigned transfer_count;
	unsigned cur_buf;
	unsigned next_buf;
	unsigned debug0;
	unsigned hs_wdth_mask;
	unsigned hs_wdth_shift;
	unsigned ipversion;
};

struct mxsfb_info {
	struct fb_info fb_info;
	struct platform_device *pdev;
	struct clk *clk;
	void __iomem *base;	/* registers */
	unsigned allocated_size;
	int enabled;
	unsigned ld_intf_width;
	unsigned dotclk_delay;
	const struct mxsfb_devdata *devdata;
	int mapped;
};

#define mxsfb_is_v3(host) (host->devdata->ipversion == 3)
#define mxsfb_is_v4(host) (host->devdata->ipversion == 4)

static const struct mxsfb_devdata mxsfb_devdata[] = {
	[MXSFB_V3] = {
		.transfer_count = LCDC_V3_TRANSFER_COUNT,
		.cur_buf = LCDC_V3_CUR_BUF,
		.next_buf = LCDC_V3_NEXT_BUF,
		.debug0 = LCDC_V3_DEBUG0,
		.hs_wdth_mask = 0xff,
		.hs_wdth_shift = 24,
		.ipversion = 3,
	},
	[MXSFB_V4] = {
		.transfer_count = LCDC_V4_TRANSFER_COUNT,
		.cur_buf = LCDC_V4_CUR_BUF,
		.next_buf = LCDC_V4_NEXT_BUF,
		.debug0 = LCDC_V4_DEBUG0,
		.hs_wdth_mask = 0x3fff,
		.hs_wdth_shift = 18,
		.ipversion = 4,
	},
};

#define to_imxfb_host(x) (container_of(x, struct mxsfb_info, fb_info))

/* mask and shift depends on architecture */
static inline u32 set_hsync_pulse_width(struct mxsfb_info *host, unsigned val)
{
	return (val & host->devdata->hs_wdth_mask) <<
		host->devdata->hs_wdth_shift;
}

static inline u32 get_hsync_pulse_width(struct mxsfb_info *host, unsigned val)
{
	return (val >> host->devdata->hs_wdth_shift) &
		host->devdata->hs_wdth_mask;
}

static const struct fb_bitfield def_rgb565[] = {
	[RED] = {
		.offset = 11,
		.length = 5,
	},
	[GREEN] = {
		.offset = 5,
		.length = 6,
	},
	[BLUE] = {
		.offset = 0,
		.length = 5,
	},
	[TRANSP] = {	/* no support for transparency */
		.length = 0,
	}
};

static const struct fb_bitfield def_rgb666[] = {
	[RED] = {
		.offset = 16,
		.length = 6,
	},
	[GREEN] = {
		.offset = 8,
		.length = 6,
	},
	[BLUE] = {
		.offset = 0,
		.length = 6,
	},
	[TRANSP] = {	/* no support for transparency */
		.length = 0,
	}
};

static const struct fb_bitfield def_rgb888[] = {
	[RED] = {
		.offset = 16,
		.length = 8,
	},
	[GREEN] = {
		.offset = 8,
		.length = 8,
	},
	[BLUE] = {
		.offset = 0,
		.length = 8,
	},
	[TRANSP] = {	/* no support for transparency */
		.length = 0,
	}
};

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

static int mxsfb_check_var(struct fb_var_screeninfo *var,
		struct fb_info *fb_info)
{
	struct mxsfb_info *host = to_imxfb_host(fb_info);
	const struct fb_bitfield *rgb = NULL;

	if (var->xres < MIN_XRES)
		var->xres = MIN_XRES;
	if (var->yres < MIN_YRES)
		var->yres = MIN_YRES;

	var->xres_virtual = var->xres;

	var->yres_virtual = var->yres;

	switch (var->bits_per_pixel) {
	case 16:
		/* always expect RGB 565 */
		rgb = def_rgb565;
		break;
	case 32:
		switch (host->ld_intf_width) {
		case STMLCDIF_8BIT:
			pr_debug("Unsupported LCD bus width mapping\n");
			break;
		case STMLCDIF_16BIT:
		case STMLCDIF_18BIT:
			/* 24 bit to 18 bit mapping */
			rgb = def_rgb666;
			break;
		case STMLCDIF_24BIT:
			/* real 24 bit */
			rgb = def_rgb888;
			break;
		}
		break;
	default:
		pr_debug("Unsupported colour depth: %u\n", var->bits_per_pixel);
		return -EINVAL;
	}

	/*
	 * Copy the RGB parameters for this display
	 * from the machine specific parameters.
	 */
	var->red    = rgb[RED];
	var->green  = rgb[GREEN];
	var->blue   = rgb[BLUE];
	var->transp = rgb[TRANSP];

	return 0;
}

static void mxsfb_enable_controller(struct fb_info *fb_info)
{
	struct mxsfb_info *host = to_imxfb_host(fb_info);
	u32 reg;

	dev_dbg(&host->pdev->dev, "%s\n", __func__);

	clk_enable(host->clk);
	clk_set_rate(host->clk, PICOS2KHZ(fb_info->var.pixclock) * 1000U);

	/* if it was disabled, re-enable the mode again */
	writel(CTRL_DOTCLK_MODE, host->base + LCDC_CTRL + REG_SET);

	/* enable the SYNC signals first, then the DMA engine */
	reg = readl(host->base + LCDC_VDCTRL4);
	reg |= VDCTRL4_SYNC_SIGNALS_ON;
	writel(reg, host->base + LCDC_VDCTRL4);

	writel(CTRL_RUN, host->base + LCDC_CTRL + REG_SET);

	host->enabled = 1;
}

static void mxsfb_disable_controller(struct fb_info *fb_info)
{
	struct mxsfb_info *host = to_imxfb_host(fb_info);
	unsigned loop;
	u32 reg;

	dev_dbg(&host->pdev->dev, "%s\n", __func__);

	/*
	 * Even if we disable the controller here, it will still continue
	 * until its FIFOs are running out of data
	 */
	writel(CTRL_DOTCLK_MODE, host->base + LCDC_CTRL + REG_CLR);

	loop = 1000;
	while (loop) {
		reg = readl(host->base + LCDC_CTRL);
		if (!(reg & CTRL_RUN))
			break;
		loop--;
	}

	writel(VDCTRL4_SYNC_SIGNALS_ON, host->base + LCDC_VDCTRL4 + REG_CLR);

	clk_disable(host->clk);

	host->enabled = 0;
}

static int mxsfb_set_par(struct fb_info *fb_info)
{
	struct mxsfb_info *host = to_imxfb_host(fb_info);
	u32 ctrl, vdctrl0, vdctrl4;
	int line_size, fb_size;
	int reenable = 0;

	line_size =  fb_info->var.xres * (fb_info->var.bits_per_pixel >> 3);
	fb_size = fb_info->var.yres_virtual * line_size;

	if (fb_size > fb_info->fix.smem_len)
		return -ENOMEM;

	fb_info->fix.line_length = line_size;

	/*
	 * It seems, you can't re-program the controller if it is still running.
	 * This may lead into shifted pictures (FIFO issue?).
	 * So, first stop the controller and drain its FIFOs
	 */
	if (host->enabled) {
		reenable = 1;
		mxsfb_disable_controller(fb_info);
	}

	/* clear the FIFOs */
	writel(CTRL1_FIFO_CLEAR, host->base + LCDC_CTRL1 + REG_SET);

	ctrl = CTRL_BYPASS_COUNT | CTRL_MASTER |
		CTRL_SET_BUS_WIDTH(host->ld_intf_width);

	switch (fb_info->var.bits_per_pixel) {
	case 16:
		dev_dbg(&host->pdev->dev, "Setting up RGB565 mode\n");
		ctrl |= CTRL_SET_WORD_LENGTH(0);
		writel(CTRL1_SET_BYTE_PACKAGING(0xf), host->base + LCDC_CTRL1);
		break;
	case 32:
		dev_dbg(&host->pdev->dev, "Setting up RGB888/666 mode\n");
		ctrl |= CTRL_SET_WORD_LENGTH(3);
		switch (host->ld_intf_width) {
		case STMLCDIF_8BIT:
			dev_dbg(&host->pdev->dev,
					"Unsupported LCD bus width mapping\n");
			return -EINVAL;
		case STMLCDIF_16BIT:
		case STMLCDIF_18BIT:
			/* 24 bit to 18 bit mapping */
			ctrl |= CTRL_DF24; /* ignore the upper 2 bits in
					    *  each colour component
					    */
			break;
		case STMLCDIF_24BIT:
			/* real 24 bit */
			break;
		}
		/* do not use packed pixels = one pixel per word instead */
		writel(CTRL1_SET_BYTE_PACKAGING(0x7), host->base + LCDC_CTRL1);
		break;
	default:
		dev_dbg(&host->pdev->dev, "Unhandled color depth of %u\n",
				fb_info->var.bits_per_pixel);
		return -EINVAL;
	}

	writel(ctrl, host->base + LCDC_CTRL);

	writel(TRANSFER_COUNT_SET_VCOUNT(fb_info->var.yres) |
			TRANSFER_COUNT_SET_HCOUNT(fb_info->var.xres),
			host->base + host->devdata->transfer_count);

	vdctrl0 = VDCTRL0_ENABLE_PRESENT |	/* always in DOTCLOCK mode */
		VDCTRL0_VSYNC_PERIOD_UNIT |
		VDCTRL0_VSYNC_PULSE_WIDTH_UNIT |
		VDCTRL0_SET_VSYNC_PULSE_WIDTH(fb_info->var.vsync_len);
	if (fb_info->var.sync & FB_SYNC_HOR_HIGH_ACT)
		vdctrl0 |= VDCTRL0_HSYNC_ACT_HIGH;
	if (fb_info->var.sync & FB_SYNC_VERT_HIGH_ACT)
		vdctrl0 |= VDCTRL0_VSYNC_ACT_HIGH;
	if (fb_info->var.sync & FB_SYNC_DATA_ENABLE_HIGH_ACT)
		vdctrl0 |= VDCTRL0_ENABLE_ACT_HIGH;
	if (fb_info->var.sync & FB_SYNC_DOTCLK_FAILING_ACT)
		vdctrl0 |= VDCTRL0_DOTCLK_ACT_FAILING;

	writel(vdctrl0, host->base + LCDC_VDCTRL0);

	/* frame length in lines */
	writel(fb_info->var.upper_margin + fb_info->var.vsync_len +
		fb_info->var.lower_margin + fb_info->var.yres,
		host->base + LCDC_VDCTRL1);

	/* line length in units of clocks or pixels */
	writel(set_hsync_pulse_width(host, fb_info->var.hsync_len) |
		VDCTRL2_SET_HSYNC_PERIOD(fb_info->var.left_margin +
		fb_info->var.hsync_len + fb_info->var.right_margin +
		fb_info->var.xres),
		host->base + LCDC_VDCTRL2);

	writel(SET_HOR_WAIT_CNT(fb_info->var.left_margin +
		fb_info->var.hsync_len) |
		SET_VERT_WAIT_CNT(fb_info->var.upper_margin +
			fb_info->var.vsync_len),
		host->base + LCDC_VDCTRL3);

	vdctrl4 = SET_DOTCLK_H_VALID_DATA_CNT(fb_info->var.xres);
	if (mxsfb_is_v4(host))
		vdctrl4 |= VDCTRL4_SET_DOTCLK_DLY(host->dotclk_delay);
	writel(vdctrl4, host->base + LCDC_VDCTRL4);

	writel(fb_info->fix.smem_start +
			fb_info->fix.line_length * fb_info->var.yoffset,
			host->base + host->devdata->next_buf);

	if (reenable)
		mxsfb_enable_controller(fb_info);

	return 0;
}

static int mxsfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
		u_int transp, struct fb_info *fb_info)
{
	unsigned int val;
	int ret = -EINVAL;

	/*
	 * If greyscale is true, then we convert the RGB value
	 * to greyscale no matter what visual we are using.
	 */
	if (fb_info->var.grayscale)
		red = green = blue = (19595 * red + 38470 * green +
					7471 * blue) >> 16;

	switch (fb_info->fix.visual) {
	case FB_VISUAL_TRUECOLOR:
		/*
		 * 12 or 16-bit True Colour.  We encode the RGB value
		 * according to the RGB bitfield information.
		 */
		if (regno < 16) {
			u32 *pal = fb_info->pseudo_palette;

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

			pal[regno] = val;
			ret = 0;
		}
		break;

	case FB_VISUAL_STATIC_PSEUDOCOLOR:
	case FB_VISUAL_PSEUDOCOLOR:
		break;
	}

	return ret;
}

static int mxsfb_blank(int blank, struct fb_info *fb_info)
{
	struct mxsfb_info *host = to_imxfb_host(fb_info);

	switch (blank) {
	case FB_BLANK_POWERDOWN:
	case FB_BLANK_VSYNC_SUSPEND:
	case FB_BLANK_HSYNC_SUSPEND:
	case FB_BLANK_NORMAL:
		if (host->enabled)
			mxsfb_disable_controller(fb_info);
		break;

	case FB_BLANK_UNBLANK:
		if (!host->enabled)
			mxsfb_enable_controller(fb_info);
		break;
	}
	return 0;
}

static int mxsfb_pan_display(struct fb_var_screeninfo *var,
		struct fb_info *fb_info)
{
	struct mxsfb_info *host = to_imxfb_host(fb_info);
	unsigned offset;

	if (var->xoffset != 0)
		return -EINVAL;

	offset = fb_info->fix.line_length * var->yoffset;

	/* update on next VSYNC */
	writel(fb_info->fix.smem_start + offset,
			host->base + host->devdata->next_buf);

	return 0;
}

static struct fb_ops mxsfb_ops = {
	.owner = THIS_MODULE,
	.fb_check_var = mxsfb_check_var,
	.fb_set_par = mxsfb_set_par,
	.fb_setcolreg = mxsfb_setcolreg,
	.fb_blank = mxsfb_blank,
	.fb_pan_display = mxsfb_pan_display,
	.fb_fillrect = cfb_fillrect,
	.fb_copyarea = cfb_copyarea,
	.fb_imageblit = cfb_imageblit,
};

static int __devinit mxsfb_restore_mode(struct mxsfb_info *host)
{
	struct fb_info *fb_info = &host->fb_info;
	unsigned line_count;
	unsigned period;
	unsigned long pa, fbsize;
	int bits_per_pixel, ofs;
	u32 transfer_count, vdctrl0, vdctrl2, vdctrl3, vdctrl4, ctrl;
	struct fb_videomode vmode;

	/* Only restore the mode when the controller is running */
	ctrl = readl(host->base + LCDC_CTRL);
	if (!(ctrl & CTRL_RUN))
		return -EINVAL;

	vdctrl0 = readl(host->base + LCDC_VDCTRL0);
	vdctrl2 = readl(host->base + LCDC_VDCTRL2);
	vdctrl3 = readl(host->base + LCDC_VDCTRL3);
	vdctrl4 = readl(host->base + LCDC_VDCTRL4);

	transfer_count = readl(host->base + host->devdata->transfer_count);

	vmode.xres = TRANSFER_COUNT_GET_HCOUNT(transfer_count);
	vmode.yres = TRANSFER_COUNT_GET_VCOUNT(transfer_count);

	switch (CTRL_GET_WORD_LENGTH(ctrl)) {
	case 0:
		bits_per_pixel = 16;
		break;
	case 3:
		bits_per_pixel = 32;
	case 1:
	default:
		return -EINVAL;
	}

	fb_info->var.bits_per_pixel = bits_per_pixel;

	vmode.pixclock = KHZ2PICOS(clk_get_rate(host->clk) / 1000U);
	vmode.hsync_len = get_hsync_pulse_width(host, vdctrl2);
	vmode.left_margin = GET_HOR_WAIT_CNT(vdctrl3) - vmode.hsync_len;
	vmode.right_margin = VDCTRL2_GET_HSYNC_PERIOD(vdctrl2) - vmode.hsync_len -
		vmode.left_margin - vmode.xres;
	vmode.vsync_len = VDCTRL0_GET_VSYNC_PULSE_WIDTH(vdctrl0);
	period = readl(host->base + LCDC_VDCTRL1);
	vmode.upper_margin = GET_VERT_WAIT_CNT(vdctrl3) - vmode.vsync_len;
	vmode.lower_margin = period - vmode.vsync_len - vmode.upper_margin - vmode.yres;

	vmode.vmode = FB_VMODE_NONINTERLACED;

	vmode.sync = 0;
	if (vdctrl0 & VDCTRL0_HSYNC_ACT_HIGH)
		vmode.sync |= FB_SYNC_HOR_HIGH_ACT;
	if (vdctrl0 & VDCTRL0_VSYNC_ACT_HIGH)
		vmode.sync |= FB_SYNC_VERT_HIGH_ACT;

	pr_debug("Reconstructed video mode:\n");
	pr_debug("%dx%d, hsync: %u left: %u, right: %u, vsync: %u, upper: %u, lower: %u\n",
			vmode.xres, vmode.yres,
			vmode.hsync_len, vmode.left_margin, vmode.right_margin,
			vmode.vsync_len, vmode.upper_margin, vmode.lower_margin);
	pr_debug("pixclk: %ldkHz\n", PICOS2KHZ(vmode.pixclock));

	fb_add_videomode(&vmode, &fb_info->modelist);

	host->ld_intf_width = CTRL_GET_BUS_WIDTH(ctrl);
	host->dotclk_delay = VDCTRL4_GET_DOTCLK_DLY(vdctrl4);

	fb_info->fix.line_length = vmode.xres * (bits_per_pixel >> 3);

	pa = readl(host->base + host->devdata->cur_buf);
	fbsize = fb_info->fix.line_length * vmode.yres;
	if (pa < fb_info->fix.smem_start)
		return -EINVAL;
	if (pa + fbsize > fb_info->fix.smem_start + fb_info->fix.smem_len)
		return -EINVAL;
	ofs = pa - fb_info->fix.smem_start;
	if (ofs) {
		memmove(fb_info->screen_base, fb_info->screen_base + ofs, fbsize);
		writel(fb_info->fix.smem_start, host->base + host->devdata->next_buf);
	}

	line_count = fb_info->fix.smem_len / fb_info->fix.line_length;
	fb_info->fix.ypanstep = 1;

	clk_enable(host->clk);
	host->enabled = 1;

	return 0;
}

static int __devinit mxsfb_init_fbinfo(struct mxsfb_info *host)
{
	struct fb_info *fb_info = &host->fb_info;
	struct fb_var_screeninfo *var = &fb_info->var;
	struct mxsfb_platform_data *pdata = host->pdev->dev.platform_data;
	dma_addr_t fb_phys;
	void *fb_virt;
	unsigned fb_size = pdata->fb_size;

	fb_info->fbops = &mxsfb_ops;
	fb_info->flags = FBINFO_FLAG_DEFAULT | FBINFO_READS_FAST;
	strlcpy(fb_info->fix.id, "mxs", sizeof(fb_info->fix.id));
	fb_info->fix.type = FB_TYPE_PACKED_PIXELS;
	fb_info->fix.ypanstep = 1;
	fb_info->fix.visual = FB_VISUAL_TRUECOLOR,
	fb_info->fix.accel = FB_ACCEL_NONE;

	var->bits_per_pixel = pdata->default_bpp ? pdata->default_bpp : 16;
	var->nonstd = 0;
	var->activate = FB_ACTIVATE_NOW;
	var->accel_flags = 0;
	var->vmode = FB_VMODE_NONINTERLACED;

	host->dotclk_delay = pdata->dotclk_delay;
	host->ld_intf_width = pdata->ld_intf_width;

	/* Memory allocation for framebuffer */
	if (pdata->fb_phys) {
		if (!fb_size)
			return -EINVAL;

		fb_phys = pdata->fb_phys;

		if (!request_mem_region(fb_phys, fb_size, host->pdev->name))
			return -ENOMEM;

		fb_virt = ioremap(fb_phys, fb_size);
		if (!fb_virt) {
			release_mem_region(fb_phys, fb_size);
			return -ENOMEM;
		}
		host->mapped = 1;
	} else {
		if (!fb_size)
			fb_size = SZ_2M; /* default */
		fb_virt = alloc_pages_exact(fb_size, GFP_DMA);
		if (!fb_virt)
			return -ENOMEM;

		fb_phys = virt_to_phys(fb_virt);
	}

	fb_info->fix.smem_start = fb_phys;
	fb_info->screen_base = fb_virt;
	fb_info->screen_size = fb_info->fix.smem_len = fb_size;

	if (mxsfb_restore_mode(host))
		memset(fb_virt, 0, fb_size);

	return 0;
}

static void __devexit mxsfb_free_videomem(struct mxsfb_info *host)
{
	struct fb_info *fb_info = &host->fb_info;

	if (host->mapped) {
		iounmap(fb_info->screen_base);
		release_mem_region(fb_info->fix.smem_start,
				fb_info->screen_size);
	} else {
		free_pages_exact(fb_info->screen_base, fb_info->fix.smem_len);
	}
}

static int __devinit mxsfb_probe(struct platform_device *pdev)
{
	struct mxsfb_platform_data *pdata = pdev->dev.platform_data;
	struct resource *res;
	struct mxsfb_info *host;
	struct fb_info *fb_info;
	struct fb_modelist *modelist;
	int i, ret;

	if (!pdata) {
		dev_err(&pdev->dev, "No platformdata. Giving up\n");
		return -ENODEV;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(&pdev->dev, "Cannot get memory IO resource\n");
		return -ENODEV;
	}

	if (!request_mem_region(res->start, resource_size(res), pdev->name))
		return -EBUSY;

	fb_info = framebuffer_alloc(sizeof(struct mxsfb_info), &pdev->dev);
	if (!fb_info) {
		dev_err(&pdev->dev, "Failed to allocate fbdev\n");
		ret = -ENOMEM;
		goto error_alloc_info;
	}

	host = to_imxfb_host(fb_info);

	host->base = ioremap(res->start, resource_size(res));
	if (!host->base) {
		dev_err(&pdev->dev, "ioremap failed\n");
		ret = -ENOMEM;
		goto error_ioremap;
	}

	host->pdev = pdev;
	platform_set_drvdata(pdev, host);

	host->devdata = &mxsfb_devdata[pdev->id_entry->driver_data];

	host->clk = clk_get(&host->pdev->dev, NULL);
	if (IS_ERR(host->clk)) {
		ret = PTR_ERR(host->clk);
		goto error_getclock;
	}

	fb_info->pseudo_palette = kmalloc(sizeof(u32) * 16, GFP_KERNEL);
	if (!fb_info->pseudo_palette) {
		ret = -ENOMEM;
		goto error_pseudo_pallette;
	}

	INIT_LIST_HEAD(&fb_info->modelist);

	ret = mxsfb_init_fbinfo(host);
	if (ret != 0)
		goto error_init_fb;

	for (i = 0; i < pdata->mode_count; i++)
		fb_add_videomode(&pdata->mode_list[i], &fb_info->modelist);

	modelist = list_first_entry(&fb_info->modelist,
			struct fb_modelist, list);
	fb_videomode_to_var(&fb_info->var, &modelist->mode);

	/* init the color fields */
	mxsfb_check_var(&fb_info->var, fb_info);

	platform_set_drvdata(pdev, fb_info);

	ret = register_framebuffer(fb_info);
	if (ret != 0) {
		dev_err(&pdev->dev,"Failed to register framebuffer\n");
		goto error_register;
	}

	if (!host->enabled) {
		writel(0, host->base + LCDC_CTRL);
		mxsfb_set_par(fb_info);
		mxsfb_enable_controller(fb_info);
	}

	dev_info(&pdev->dev, "initialized\n");

	return 0;

error_register:
	if (host->enabled)
		clk_disable(host->clk);
	fb_destroy_modelist(&fb_info->modelist);
error_init_fb:
	kfree(fb_info->pseudo_palette);
error_pseudo_pallette:
	clk_put(host->clk);
error_getclock:
	iounmap(host->base);
error_ioremap:
	framebuffer_release(fb_info);
error_alloc_info:
	release_mem_region(res->start, resource_size(res));

	return ret;
}

static int __devexit mxsfb_remove(struct platform_device *pdev)
{
	struct fb_info *fb_info = platform_get_drvdata(pdev);
	struct mxsfb_info *host = to_imxfb_host(fb_info);
	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (host->enabled)
		mxsfb_disable_controller(fb_info);

	unregister_framebuffer(fb_info);
	kfree(fb_info->pseudo_palette);
	mxsfb_free_videomem(host);
	iounmap(host->base);
	clk_put(host->clk);

	framebuffer_release(fb_info);
	release_mem_region(res->start, resource_size(res));

	platform_set_drvdata(pdev, NULL);

	return 0;
}

static struct platform_device_id mxsfb_devtype[] = {
	{
		.name = "imx23-fb",
		.driver_data = MXSFB_V3,
	}, {
		.name = "imx28-fb",
		.driver_data = MXSFB_V4,
	}, {
		/* sentinel */
	}
};
MODULE_DEVICE_TABLE(platform, mxsfb_devtype);

static struct platform_driver mxsfb_driver = {
	.probe = mxsfb_probe,
	.remove = __devexit_p(mxsfb_remove),
	.id_table = mxsfb_devtype,
	.driver = {
		   .name = DRIVER_NAME,
	},
};

static int __init mxsfb_init(void)
{
	return platform_driver_register(&mxsfb_driver);
}

static void __exit mxsfb_exit(void)
{
	platform_driver_unregister(&mxsfb_driver);
}

module_init(mxsfb_init);
module_exit(mxsfb_exit);

MODULE_DESCRIPTION("Freescale mxs framebuffer driver");
MODULE_AUTHOR("Sascha Hauer, Pengutronix");
MODULE_LICENSE("GPL");