/*
 * 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/module.h>
#include <linux/kernel.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/fb.h>
#include <linux/regulator/consumer.h>
#include <video/of_display_timing.h>
#include <video/of_videomode.h>
#include <video/videomode.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_FALLING      (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

#define STMLCDIF_8BIT  1 /** pixel data bus to the display is of 8 bit width */
#define STMLCDIF_16BIT 0 /** pixel data bus to the display is of 16 bit width */
#define STMLCDIF_18BIT 2 /** pixel data bus to the display is of 18 bit width */
#define STMLCDIF_24BIT 3 /** pixel data bus to the display is of 24 bit width */

#define MXSFB_SYNC_DATA_ENABLE_HIGH_ACT (1 << 6)
#define MXSFB_SYNC_DOTCLK_FALLING_ACT   (1 << 7) /* negtive edge sampling */

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;
        struct clk *clk_axi;
        struct clk *clk_disp_axi;
        void __iomem *base;     /* registers */
        unsigned allocated_size;
        int enabled;
        unsigned ld_intf_width;
        unsigned dotclk_delay;
        const struct mxsfb_devdata *devdata;
        u32 sync;
        struct regulator *reg_lcd;
};

#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_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:
                case STMLCDIF_24BIT:
                        /* real 24 bit */
                        rgb = def_rgb888;
                        break;
                }
                break;
        default:
                pr_err("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 inline void mxsfb_enable_axi_clk(struct mxsfb_info *host)
{
        if (host->clk_axi)
                clk_prepare_enable(host->clk_axi);
}

static inline void mxsfb_disable_axi_clk(struct mxsfb_info *host)
{
        if (host->clk_axi)
                clk_disable_unprepare(host->clk_axi);
}

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

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

        if (host->reg_lcd) {
                ret = regulator_enable(host->reg_lcd);
                if (ret) {
                        dev_err(&host->pdev->dev,
                                "lcd regulator enable failed:   %d\n", ret);
                        return;
                }
        }

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

        mxsfb_enable_axi_clk(host);

        /* 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;
        int ret;

        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--;
        }

        reg = readl(host->base + LCDC_VDCTRL4);
        writel(reg & ~VDCTRL4_SYNC_SIGNALS_ON, host->base + LCDC_VDCTRL4);

        mxsfb_disable_axi_clk(host);

        clk_disable_unprepare(host->clk);
        if (host->clk_disp_axi)
                clk_disable_unprepare(host->clk_disp_axi);

        host->enabled = 0;

        if (host->reg_lcd) {
                ret = regulator_disable(host->reg_lcd);
                if (ret)
                        dev_err(&host->pdev->dev,
                                "lcd regulator disable failed: %d\n", ret);
        }
}

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);
        }

        mxsfb_enable_axi_clk(host);

        /* 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:
                        mxsfb_disable_axi_clk(host);
                        dev_err(&host->pdev->dev,
                                        "Unsupported LCD bus width mapping\n");
                        return -EINVAL;
                case STMLCDIF_16BIT:
                case STMLCDIF_18BIT:
                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:
                mxsfb_disable_axi_clk(host);
                dev_err(&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 (host->sync & MXSFB_SYNC_DATA_ENABLE_HIGH_ACT)
                vdctrl0 |= VDCTRL0_ENABLE_ACT_HIGH;
        if (host->sync & MXSFB_SYNC_DOTCLK_FALLING_ACT)
                vdctrl0 |= VDCTRL0_DOTCLK_ACT_FALLING;

        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);

        mxsfb_disable_axi_clk(host);

        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;

        mxsfb_enable_axi_clk(host);

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

        mxsfb_disable_axi_clk(host);

        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 mxsfb_restore_mode(struct mxsfb_info *host,
                        struct fb_videomode *vmode)
{
        struct fb_info *fb_info = &host->fb_info;
        unsigned line_count;
        unsigned period;
        unsigned long pa, fbsize;
        int bits_per_pixel, ofs, ret = 0;
        u32 transfer_count, vdctrl0, vdctrl2, vdctrl3, vdctrl4, ctrl;

        mxsfb_enable_axi_clk(host);

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

        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;
                break;
        case 1:
        default:
                ret = -EINVAL;
                goto err;
        }

        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));

        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) {
                ret = -EINVAL;
                goto err;
        }
        if (pa + fbsize > fb_info->fix.smem_start + fb_info->fix.smem_len) {
                ret = -EINVAL;
                goto err;
        }
        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_prepare_enable(host->clk);
        host->enabled = 1;

err:
        if (ret)
                mxsfb_disable_axi_clk(host);

        return ret;
}

static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host,
                                struct fb_videomode *vmode)
{
        struct fb_info *fb_info = &host->fb_info;
        struct fb_var_screeninfo *var = &fb_info->var;
        struct device *dev = &host->pdev->dev;
        struct device_node *np = host->pdev->dev.of_node;
        struct device_node *display_np;
        struct videomode vm;
        u32 width;
        int ret;

        display_np = of_parse_phandle(np, "display", 0);
        if (!display_np) {
                dev_err(dev, "failed to find display phandle\n");
                return -ENOENT;
        }

        ret = of_property_read_u32(display_np, "bus-width", &width);
        if (ret < 0) {
                dev_err(dev, "failed to get property bus-width\n");
                goto put_display_node;
        }

        switch (width) {
        case 8:
                host->ld_intf_width = STMLCDIF_8BIT;
                break;
        case 16:
                host->ld_intf_width = STMLCDIF_16BIT;
                break;
        case 18:
                host->ld_intf_width = STMLCDIF_18BIT;
                break;
        case 24:
                host->ld_intf_width = STMLCDIF_24BIT;
                break;
        default:
                dev_err(dev, "invalid bus-width value\n");
                ret = -EINVAL;
                goto put_display_node;
        }

        ret = of_property_read_u32(display_np, "bits-per-pixel",
                                   &var->bits_per_pixel);
        if (ret < 0) {
                dev_err(dev, "failed to get property bits-per-pixel\n");
                goto put_display_node;
        }

        ret = of_get_videomode(display_np, &vm, OF_USE_NATIVE_MODE);
        if (ret) {
                dev_err(dev, "failed to get videomode from DT\n");
                goto put_display_node;
        }

        ret = fb_videomode_from_videomode(&vm, vmode);
        if (ret < 0)
                goto put_display_node;

        if (vm.flags & DISPLAY_FLAGS_DE_HIGH)
                host->sync |= MXSFB_SYNC_DATA_ENABLE_HIGH_ACT;
        if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE)
                host->sync |= MXSFB_SYNC_DOTCLK_FALLING_ACT;

put_display_node:
        of_node_put(display_np);
        return ret;
}

static int mxsfb_init_fbinfo(struct mxsfb_info *host,
                        struct fb_videomode *vmode)
{
        int ret;
        struct fb_info *fb_info = &host->fb_info;
        struct fb_var_screeninfo *var = &fb_info->var;
        dma_addr_t fb_phys;
        void *fb_virt;
        unsigned 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;

        ret = mxsfb_init_fbinfo_dt(host, vmode);
        if (ret)
                return ret;

        var->nonstd = 0;
        var->activate = FB_ACTIVATE_NOW;
        var->accel_flags = 0;
        var->vmode = FB_VMODE_NONINTERLACED;

        /* Memory allocation for framebuffer */
        fb_size = SZ_2M;
        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, vmode))
                memset(fb_virt, 0, fb_size);

        return 0;
}

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

        free_pages_exact(fb_info->screen_base, fb_info->fix.smem_len);
}

static const 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 const struct of_device_id mxsfb_dt_ids[] = {
        { .compatible = "fsl,imx23-lcdif", .data = &mxsfb_devtype[0], },
        { .compatible = "fsl,imx28-lcdif", .data = &mxsfb_devtype[1], },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxsfb_dt_ids);

static int mxsfb_probe(struct platform_device *pdev)
{
        const struct of_device_id *of_id =
                        of_match_device(mxsfb_dt_ids, &pdev->dev);
        struct resource *res;
        struct mxsfb_info *host;
        struct fb_info *fb_info;
        struct fb_videomode *mode;
        int ret;

        if (of_id)
                pdev->id_entry = of_id->data;

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

        mode = devm_kzalloc(&pdev->dev, sizeof(struct fb_videomode),
                        GFP_KERNEL);
        if (mode == NULL)
                return -ENOMEM;

        host = to_imxfb_host(fb_info);

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        host->base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(host->base)) {
                ret = PTR_ERR(host->base);
                goto fb_release;
        }

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

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

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

        host->clk_axi = devm_clk_get(&host->pdev->dev, "axi");
        if (IS_ERR(host->clk_axi))
                host->clk_axi = NULL;

        host->clk_disp_axi = devm_clk_get(&host->pdev->dev, "disp_axi");
        if (IS_ERR(host->clk_disp_axi))
                host->clk_disp_axi = NULL;

        host->reg_lcd = devm_regulator_get(&pdev->dev, "lcd");
        if (IS_ERR(host->reg_lcd))
                host->reg_lcd = NULL;

        fb_info->pseudo_palette = devm_kzalloc(&pdev->dev, sizeof(u32) * 16,
                                               GFP_KERNEL);
        if (!fb_info->pseudo_palette) {
                ret = -ENOMEM;
                goto fb_release;
        }

        ret = mxsfb_init_fbinfo(host, mode);
        if (ret != 0)
                goto fb_release;

        fb_videomode_to_var(&fb_info->var, 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 fb_destroy;
        }

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

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

        return 0;

fb_destroy:
        if (host->enabled)
                clk_disable_unprepare(host->clk);
fb_release:
        framebuffer_release(fb_info);

        return ret;
}

static int mxsfb_remove(struct platform_device *pdev)
{
        struct fb_info *fb_info = platform_get_drvdata(pdev);
        struct mxsfb_info *host = to_imxfb_host(fb_info);

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

        unregister_framebuffer(fb_info);
        mxsfb_free_videomem(host);

        framebuffer_release(fb_info);

        return 0;
}

static void mxsfb_shutdown(struct platform_device *pdev)
{
        struct fb_info *fb_info = platform_get_drvdata(pdev);
        struct mxsfb_info *host = to_imxfb_host(fb_info);

        mxsfb_enable_axi_clk(host);

        /*
         * Force stop the LCD controller as keeping it running during reboot
         * might interfere with the BootROM's boot mode pads sampling.
         */
        writel(CTRL_RUN, host->base + LCDC_CTRL + REG_CLR);

        mxsfb_disable_axi_clk(host);
}

static struct platform_driver mxsfb_driver = {
        .probe = mxsfb_probe,
        .remove = mxsfb_remove,
        .shutdown = mxsfb_shutdown,
        .id_table = mxsfb_devtype,
        .driver = {
                   .name = DRIVER_NAME,
                   .of_match_table = mxsfb_dt_ids,
        },
};

module_platform_driver(mxsfb_driver);

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