imxfb.c

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/*
 *  Freescale i.MX Frame Buffer device driver
 *
 *  Copyright (C) 2004 Sascha Hauer, Pengutronix
 *   Based on acornfb.c Copyright (C) Russell King.
 *
 * 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.
 *
 * Please direct your questions and comments on this driver to the following
 * email address:
 *
 *  [email protected]
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/fb.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/cpufreq.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/math64.h>

#include <linux/platform_data/video-imxfb.h>
#include <mach/hardware.h>

/*
 * Complain if VAR is out of range.
 */
#define DEBUG_VAR 1

#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || \
    (defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE) && \
        defined(CONFIG_FB_IMX_MODULE))
#define PWMR_BACKLIGHT_AVAILABLE
#endif

#define DRIVER_NAME "imx-fb"

#define LCDC_SSA    0x00

#define LCDC_SIZE   0x04
#define SIZE_XMAX(x)    ((((x) >> 4) & 0x3f) << 20)

#define YMAX_MASK       (cpu_is_mx1() ? 0x1ff : 0x3ff)
#define SIZE_YMAX(y)    ((y) & YMAX_MASK)

#define LCDC_VPW    0x08
#define VPW_VPW(x)  ((x) & 0x3ff)

#define LCDC_CPOS   0x0C
#define CPOS_CC1    (1<<31)
#define CPOS_CC0    (1<<30)
#define CPOS_OP     (1<<28)
#define CPOS_CXP(x) (((x) & 3ff) << 16)

#define LCDC_LCWHB  0x10
#define LCWHB_BK_EN (1<<31)
#define LCWHB_CW(w) (((w) & 0x1f) << 24)
#define LCWHB_CH(h) (((h) & 0x1f) << 16)
#define LCWHB_BD(x) ((x) & 0xff)

#define LCDC_LCHCC  0x14

#define LCDC_PCR    0x18

#define LCDC_HCR    0x1C
#define HCR_H_WIDTH(x)  (((x) & 0x3f) << 26)
#define HCR_H_WAIT_1(x) (((x) & 0xff) << 8)
#define HCR_H_WAIT_2(x) ((x) & 0xff)

#define LCDC_VCR    0x20
#define VCR_V_WIDTH(x)  (((x) & 0x3f) << 26)
#define VCR_V_WAIT_1(x) (((x) & 0xff) << 8)
#define VCR_V_WAIT_2(x) ((x) & 0xff)

#define LCDC_POS    0x24
#define POS_POS(x)  ((x) & 1f)

#define LCDC_LSCR1  0x28
/* bit fields in imxfb.h */

#define LCDC_PWMR   0x2C
/* bit fields in imxfb.h */

#define LCDC_DMACR  0x30
/* bit fields in imxfb.h */

#define LCDC_RMCR   0x34

#define RMCR_LCDC_EN_MX1    (1<<1)

#define RMCR_SELF_REF   (1<<0)

#define LCDC_LCDICR 0x38
#define LCDICR_INT_SYN  (1<<2)
#define LCDICR_INT_CON  (1)

#define LCDC_LCDISR 0x40
#define LCDISR_UDR_ERR  (1<<3)
#define LCDISR_ERR_RES  (1<<2)
#define LCDISR_EOF  (1<<1)
#define LCDISR_BOF  (1<<0)

/* Used fb-mode. Can be set on kernel command line, therefore file-static. */
static const char *fb_mode;


/*
 * These are the bitfields for each
 * display depth that we support.
 */
struct imxfb_rgb {
    struct fb_bitfield  red;
    struct fb_bitfield  green;
    struct fb_bitfield  blue;
    struct fb_bitfield  transp;
};

struct imxfb_info {
    struct platform_device  *pdev;
    void __iomem        *regs;
    struct clk      *clk_ipg;
    struct clk      *clk_ahb;
    struct clk      *clk_per;

    /*
     * These are the addresses we mapped
     * the framebuffer memory region to.
     */
    dma_addr_t      map_dma;
    u_char          *map_cpu;
    u_int           map_size;

    u_char          *screen_cpu;
    dma_addr_t      screen_dma;
    u_int           palette_size;

    dma_addr_t      dbar1;
    dma_addr_t      dbar2;

    u_int           pcr;
    u_int           pwmr;
    u_int           lscr1;
    u_int           dmacr;
    u_int           cmap_inverse:1,
                cmap_static:1,
                unused:30;

    struct imx_fb_videomode *mode;
    int         num_modes;
#ifdef PWMR_BACKLIGHT_AVAILABLE
    struct backlight_device *bl;
#endif

    void (*lcd_power)(int);
    void (*backlight_power)(int);
};

#define IMX_NAME    "IMX"

/*
 * Minimum X and Y resolutions
 */
#define MIN_XRES    64
#define MIN_YRES    64

/* Actually this really is 18bit support, the lowest 2 bits of each colour
 * are unused in hardware. We claim to have 24bit support to make software
 * like X work, which does not support 18bit.
 */
static struct imxfb_rgb def_rgb_18 = {
    .red    = {.offset = 16, .length = 8,},
    .green  = {.offset = 8, .length = 8,},
    .blue   = {.offset = 0, .length = 8,},
    .transp = {.offset = 0, .length = 0,},
};

static struct imxfb_rgb def_rgb_16_tft = {
    .red    = {.offset = 11, .length = 5,},
    .green  = {.offset = 5, .length = 6,},
    .blue   = {.offset = 0, .length = 5,},
    .transp = {.offset = 0, .length = 0,},
};

static struct imxfb_rgb def_rgb_16_stn = {
    .red    = {.offset = 8, .length = 4,},
    .green  = {.offset = 4, .length = 4,},
    .blue   = {.offset = 0, .length = 4,},
    .transp = {.offset = 0, .length = 0,},
};

static struct imxfb_rgb def_rgb_8 = {
    .red    = {.offset = 0, .length = 8,},
    .green  = {.offset = 0, .length = 8,},
    .blue   = {.offset = 0, .length = 8,},
    .transp = {.offset = 0, .length = 0,},
};

static int imxfb_activate_var(struct fb_var_screeninfo *var,
        struct fb_info *info);

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

static int imxfb_setpalettereg(u_int regno, u_int red, u_int green, u_int blue,
        u_int trans, struct fb_info *info)
{
    struct imxfb_info *fbi = info->par;
    u_int val, ret = 1;

#define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
    if (regno < fbi->palette_size) {
        val = (CNVT_TOHW(red, 4) << 8) |
              (CNVT_TOHW(green,4) << 4) |
              CNVT_TOHW(blue,  4);

        writel(val, fbi->regs + 0x800 + (regno << 2));
        ret = 0;
    }
    return ret;
}

static int imxfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
           u_int trans, struct fb_info *info)
{
    struct imxfb_info *fbi = info->par;
    unsigned int val;
    int ret = 1;

    /*
     * If inverse mode was selected, invert all the colours
     * rather than the register number.  The register number
     * is what you poke into the framebuffer to produce the
     * colour you requested.
     */
    if (fbi->cmap_inverse) {
        red   = 0xffff - red;
        green = 0xffff - green;
        blue  = 0xffff - blue;
    }

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

    switch (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 = 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;
            ret = 0;
        }
        break;

    case FB_VISUAL_STATIC_PSEUDOCOLOR:
    case FB_VISUAL_PSEUDOCOLOR:
        ret = imxfb_setpalettereg(regno, red, green, blue, trans, info);
        break;
    }

    return ret;
}

static const struct imx_fb_videomode *imxfb_find_mode(struct imxfb_info *fbi)
{
    struct imx_fb_videomode *m;
    int i;

    for (i = 0, m = &fbi->mode[0]; i < fbi->num_modes; i++, m++) {
        if (!strcmp(m->mode.name, fb_mode))
            return m;
    }
    return NULL;
}

/*
 *  imxfb_check_var():
 *    Round up in the following order: bits_per_pixel, xres,
 *    yres, xres_virtual, yres_virtual, xoffset, yoffset, grayscale,
 *    bitfields, horizontal timing, vertical timing.
 */
static int imxfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
{
    struct imxfb_info *fbi = info->par;
    struct imxfb_rgb *rgb;
    const struct imx_fb_videomode *imxfb_mode;
    unsigned long lcd_clk;
    unsigned long long tmp;
    u32 pcr = 0;

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

    imxfb_mode = imxfb_find_mode(fbi);
    if (!imxfb_mode)
        return -EINVAL;

    var->xres       = imxfb_mode->mode.xres;
    var->yres       = imxfb_mode->mode.yres;
    var->bits_per_pixel = imxfb_mode->bpp;
    var->pixclock       = imxfb_mode->mode.pixclock;
    var->hsync_len      = imxfb_mode->mode.hsync_len;
    var->left_margin    = imxfb_mode->mode.left_margin;
    var->right_margin   = imxfb_mode->mode.right_margin;
    var->vsync_len      = imxfb_mode->mode.vsync_len;
    var->upper_margin   = imxfb_mode->mode.upper_margin;
    var->lower_margin   = imxfb_mode->mode.lower_margin;
    var->sync       = imxfb_mode->mode.sync;
    var->xres_virtual   = max(var->xres_virtual, var->xres);
    var->yres_virtual   = max(var->yres_virtual, var->yres);

    pr_debug("var->bits_per_pixel=%d\n", var->bits_per_pixel);

    lcd_clk = clk_get_rate(fbi->clk_per);

    tmp = var->pixclock * (unsigned long long)lcd_clk;

    do_div(tmp, 1000000);

    if (do_div(tmp, 1000000) > 500000)
        tmp++;

    pcr = (unsigned int)tmp;

    if (--pcr > 0x3F) {
        pcr = 0x3F;
        printk(KERN_WARNING "Must limit pixel clock to %luHz\n",
                lcd_clk / pcr);
    }

    switch (var->bits_per_pixel) {
    case 32:
        pcr |= PCR_BPIX_18;
        rgb = &def_rgb_18;
        break;
    case 16:
    default:
        if (cpu_is_mx1())
            pcr |= PCR_BPIX_12;
        else
            pcr |= PCR_BPIX_16;

        if (imxfb_mode->pcr & PCR_TFT)
            rgb = &def_rgb_16_tft;
        else
            rgb = &def_rgb_16_stn;
        break;
    case 8:
        pcr |= PCR_BPIX_8;
        rgb = &def_rgb_8;
        break;
    }

    /* add sync polarities */
    pcr |= imxfb_mode->pcr & ~(0x3f | (7 << 25));

    fbi->pcr = pcr;

    /*
     * 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;

    pr_debug("RGBT length = %d:%d:%d:%d\n",
        var->red.length, var->green.length, var->blue.length,
        var->transp.length);

    pr_debug("RGBT offset = %d:%d:%d:%d\n",
        var->red.offset, var->green.offset, var->blue.offset,
        var->transp.offset);

    return 0;
}

/*
 * imxfb_set_par():
 *  Set the user defined part of the display for the specified console
 */
static int imxfb_set_par(struct fb_info *info)
{
    struct imxfb_info *fbi = info->par;
    struct fb_var_screeninfo *var = &info->var;

    if (var->bits_per_pixel == 16 || var->bits_per_pixel == 32)
        info->fix.visual = FB_VISUAL_TRUECOLOR;
    else if (!fbi->cmap_static)
        info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
    else {
        /*
         * Some people have weird ideas about wanting static
         * pseudocolor maps.  I suspect their user space
         * applications are broken.
         */
        info->fix.visual = FB_VISUAL_STATIC_PSEUDOCOLOR;
    }

    info->fix.line_length = var->xres_virtual * var->bits_per_pixel / 8;
    fbi->palette_size = var->bits_per_pixel == 8 ? 256 : 16;

    imxfb_activate_var(var, info);

    return 0;
}

#ifdef PWMR_BACKLIGHT_AVAILABLE
static int imxfb_bl_get_brightness(struct backlight_device *bl)
{
    struct imxfb_info *fbi = bl_get_data(bl);

    return readl(fbi->regs + LCDC_PWMR) & 0xFF;
}

static int imxfb_bl_update_status(struct backlight_device *bl)
{
    struct imxfb_info *fbi = bl_get_data(bl);
    int brightness = bl->props.brightness;

    if (bl->props.power != FB_BLANK_UNBLANK)
        brightness = 0;
    if (bl->props.fb_blank != FB_BLANK_UNBLANK)
        brightness = 0;

    fbi->pwmr = (fbi->pwmr & ~0xFF) | brightness;

    if (bl->props.fb_blank != FB_BLANK_UNBLANK) {
        clk_prepare_enable(fbi->clk_ipg);
        clk_prepare_enable(fbi->clk_ahb);
        clk_prepare_enable(fbi->clk_per);
    }
    writel(fbi->pwmr, fbi->regs + LCDC_PWMR);
    if (bl->props.fb_blank != FB_BLANK_UNBLANK) {
        clk_disable_unprepare(fbi->clk_per);
        clk_disable_unprepare(fbi->clk_ahb);
        clk_disable_unprepare(fbi->clk_ipg);
    }

    return 0;
}

static const struct backlight_ops imxfb_lcdc_bl_ops = {
    .update_status = imxfb_bl_update_status,
    .get_brightness = imxfb_bl_get_brightness,
};

static void imxfb_init_backlight(struct imxfb_info *fbi)
{
    struct backlight_properties props;
    struct backlight_device *bl;

    if (fbi->bl)
        return;

    memset(&props, 0, sizeof(struct backlight_properties));
    props.max_brightness = 0xff;
    props.type = BACKLIGHT_RAW;
    writel(fbi->pwmr, fbi->regs + LCDC_PWMR);

    bl = backlight_device_register("imxfb-bl", &fbi->pdev->dev, fbi,
                       &imxfb_lcdc_bl_ops, &props);
    if (IS_ERR(bl)) {
        dev_err(&fbi->pdev->dev, "error %ld on backlight register\n",
                PTR_ERR(bl));
        return;
    }

    fbi->bl = bl;
    bl->props.power = FB_BLANK_UNBLANK;
    bl->props.fb_blank = FB_BLANK_UNBLANK;
    bl->props.brightness = imxfb_bl_get_brightness(bl);
}

static void imxfb_exit_backlight(struct imxfb_info *fbi)
{
    if (fbi->bl)
        backlight_device_unregister(fbi->bl);
}
#endif

static void imxfb_enable_controller(struct imxfb_info *fbi)
{
    pr_debug("Enabling LCD controller\n");

    writel(fbi->screen_dma, fbi->regs + LCDC_SSA);

    /* panning offset 0 (0 pixel offset)        */
    writel(0x00000000, fbi->regs + LCDC_POS);

    /* disable hardware cursor */
    writel(readl(fbi->regs + LCDC_CPOS) & ~(CPOS_CC0 | CPOS_CC1),
        fbi->regs + LCDC_CPOS);

    /*
     * RMCR_LCDC_EN_MX1 is present on i.MX1 only, but doesn't hurt
     * on other SoCs
     */
    writel(RMCR_LCDC_EN_MX1, fbi->regs + LCDC_RMCR);

    clk_prepare_enable(fbi->clk_ipg);
    clk_prepare_enable(fbi->clk_ahb);
    clk_prepare_enable(fbi->clk_per);

    if (fbi->backlight_power)
        fbi->backlight_power(1);
    if (fbi->lcd_power)
        fbi->lcd_power(1);
}

static void imxfb_disable_controller(struct imxfb_info *fbi)
{
    pr_debug("Disabling LCD controller\n");

    if (fbi->backlight_power)
        fbi->backlight_power(0);
    if (fbi->lcd_power)
        fbi->lcd_power(0);

    clk_disable_unprepare(fbi->clk_per);
    clk_disable_unprepare(fbi->clk_ipg);
    clk_disable_unprepare(fbi->clk_ahb);

    writel(0, fbi->regs + LCDC_RMCR);
}

static int imxfb_blank(int blank, struct fb_info *info)
{
    struct imxfb_info *fbi = info->par;

    pr_debug("imxfb_blank: blank=%d\n", blank);

    switch (blank) {
    case FB_BLANK_POWERDOWN:
    case FB_BLANK_VSYNC_SUSPEND:
    case FB_BLANK_HSYNC_SUSPEND:
    case FB_BLANK_NORMAL:
        imxfb_disable_controller(fbi);
        break;

    case FB_BLANK_UNBLANK:
        imxfb_enable_controller(fbi);
        break;
    }
    return 0;
}

static struct fb_ops imxfb_ops = {
    .owner      = THIS_MODULE,
    .fb_check_var   = imxfb_check_var,
    .fb_set_par = imxfb_set_par,
    .fb_setcolreg   = imxfb_setcolreg,
    .fb_fillrect    = cfb_fillrect,
    .fb_copyarea    = cfb_copyarea,
    .fb_imageblit   = cfb_imageblit,
    .fb_blank   = imxfb_blank,
};

/*
 * imxfb_activate_var():
 *  Configures LCD Controller based on entries in var parameter.  Settings are
 *  only written to the controller if changes were made.
 */
static int imxfb_activate_var(struct fb_var_screeninfo *var, struct fb_info *info)
{
    struct imxfb_info *fbi = info->par;

    pr_debug("var: xres=%d hslen=%d lm=%d rm=%d\n",
        var->xres, var->hsync_len,
        var->left_margin, var->right_margin);
    pr_debug("var: yres=%d vslen=%d um=%d bm=%d\n",
        var->yres, var->vsync_len,
        var->upper_margin, var->lower_margin);

#if DEBUG_VAR
    if (var->xres < 16        || var->xres > 1024)
        printk(KERN_ERR "%s: invalid xres %d\n",
            info->fix.id, var->xres);
    if (var->hsync_len < 1    || var->hsync_len > 64)
        printk(KERN_ERR "%s: invalid hsync_len %d\n",
            info->fix.id, var->hsync_len);
    if (var->left_margin > 255)
        printk(KERN_ERR "%s: invalid left_margin %d\n",
            info->fix.id, var->left_margin);
    if (var->right_margin > 255)
        printk(KERN_ERR "%s: invalid right_margin %d\n",
            info->fix.id, var->right_margin);
    if (var->yres < 1 || var->yres > YMAX_MASK)
        printk(KERN_ERR "%s: invalid yres %d\n",
            info->fix.id, var->yres);
    if (var->vsync_len > 100)
        printk(KERN_ERR "%s: invalid vsync_len %d\n",
            info->fix.id, var->vsync_len);
    if (var->upper_margin > 63)
        printk(KERN_ERR "%s: invalid upper_margin %d\n",
            info->fix.id, var->upper_margin);
    if (var->lower_margin > 255)
        printk(KERN_ERR "%s: invalid lower_margin %d\n",
            info->fix.id, var->lower_margin);
#endif

    /* physical screen start address        */
    writel(VPW_VPW(var->xres * var->bits_per_pixel / 8 / 4),
        fbi->regs + LCDC_VPW);

    writel(HCR_H_WIDTH(var->hsync_len - 1) |
        HCR_H_WAIT_1(var->right_margin - 1) |
        HCR_H_WAIT_2(var->left_margin - 3),
        fbi->regs + LCDC_HCR);

    writel(VCR_V_WIDTH(var->vsync_len) |
        VCR_V_WAIT_1(var->lower_margin) |
        VCR_V_WAIT_2(var->upper_margin),
        fbi->regs + LCDC_VCR);

    writel(SIZE_XMAX(var->xres) | SIZE_YMAX(var->yres),
            fbi->regs + LCDC_SIZE);

    writel(fbi->pcr, fbi->regs + LCDC_PCR);
#ifndef PWMR_BACKLIGHT_AVAILABLE
    writel(fbi->pwmr, fbi->regs + LCDC_PWMR);
#endif
    writel(fbi->lscr1, fbi->regs + LCDC_LSCR1);
    writel(fbi->dmacr, fbi->regs + LCDC_DMACR);

    return 0;
}

#ifdef CONFIG_PM
/*
 * Power management hooks.  Note that we won't be called from IRQ context,
 * unlike the blank functions above, so we may sleep.
 */
static int imxfb_suspend(struct platform_device *dev, pm_message_t state)
{
    struct fb_info *info = platform_get_drvdata(dev);
    struct imxfb_info *fbi = info->par;

    pr_debug("%s\n", __func__);

    imxfb_disable_controller(fbi);
    return 0;
}

static int imxfb_resume(struct platform_device *dev)
{
    struct fb_info *info = platform_get_drvdata(dev);
    struct imxfb_info *fbi = info->par;

    pr_debug("%s\n", __func__);

    imxfb_enable_controller(fbi);
    return 0;
}
#else
#define imxfb_suspend   NULL
#define imxfb_resume    NULL
#endif

static int __init imxfb_init_fbinfo(struct platform_device *pdev)
{
    struct imx_fb_platform_data *pdata = pdev->dev.platform_data;
    struct fb_info *info = dev_get_drvdata(&pdev->dev);
    struct imxfb_info *fbi = info->par;
    struct imx_fb_videomode *m;
    int i;

    pr_debug("%s\n",__func__);

    info->pseudo_palette = kmalloc(sizeof(u32) * 16, GFP_KERNEL);
    if (!info->pseudo_palette)
        return -ENOMEM;

    memset(fbi, 0, sizeof(struct imxfb_info));

    strlcpy(info->fix.id, IMX_NAME, sizeof(info->fix.id));

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

    info->var.nonstd        = 0;
    info->var.activate      = FB_ACTIVATE_NOW;
    info->var.height        = -1;
    info->var.width = -1;
    info->var.accel_flags       = 0;
    info->var.vmode         = FB_VMODE_NONINTERLACED;

    info->fbops         = &imxfb_ops;
    info->flags         = FBINFO_FLAG_DEFAULT |
                      FBINFO_READS_FAST;
    info->var.grayscale     = pdata->cmap_greyscale;
    fbi->cmap_inverse       = pdata->cmap_inverse;
    fbi->cmap_static        = pdata->cmap_static;
    fbi->lscr1          = pdata->lscr1;
    fbi->dmacr          = pdata->dmacr;
    fbi->pwmr           = pdata->pwmr;
    fbi->lcd_power          = pdata->lcd_power;
    fbi->backlight_power        = pdata->backlight_power;

    for (i = 0, m = &pdata->mode[0]; i < pdata->num_modes; i++, m++)
        info->fix.smem_len = max_t(size_t, info->fix.smem_len,
                m->mode.xres * m->mode.yres * m->bpp / 8);

    return 0;
}

static int __init imxfb_probe(struct platform_device *pdev)
{
    struct imxfb_info *fbi;
    struct fb_info *info;
    struct imx_fb_platform_data *pdata;
    struct resource *res;
    int ret, i;

    dev_info(&pdev->dev, "i.MX Framebuffer driver\n");

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res)
        return -ENODEV;

    pdata = pdev->dev.platform_data;
    if (!pdata) {
        dev_err(&pdev->dev,"No platform_data available\n");
        return -ENOMEM;
    }

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

    fbi = info->par;

    if (!fb_mode)
        fb_mode = pdata->mode[0].mode.name;

    platform_set_drvdata(pdev, info);

    ret = imxfb_init_fbinfo(pdev);
    if (ret < 0)
        goto failed_init;

    res = request_mem_region(res->start, resource_size(res),
                DRIVER_NAME);
    if (!res) {
        ret = -EBUSY;
        goto failed_req;
    }

    fbi->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
    if (IS_ERR(fbi->clk_ipg)) {
        ret = PTR_ERR(fbi->clk_ipg);
        goto failed_getclock;
    }

    fbi->clk_ahb = devm_clk_get(&pdev->dev, "ahb");
    if (IS_ERR(fbi->clk_ahb)) {
        ret = PTR_ERR(fbi->clk_ahb);
        goto failed_getclock;
    }

    fbi->clk_per = devm_clk_get(&pdev->dev, "per");
    if (IS_ERR(fbi->clk_per)) {
        ret = PTR_ERR(fbi->clk_per);
        goto failed_getclock;
    }

    fbi->regs = ioremap(res->start, resource_size(res));
    if (fbi->regs == NULL) {
        dev_err(&pdev->dev, "Cannot map frame buffer registers\n");
        ret = -ENOMEM;
        goto failed_ioremap;
    }

    if (!pdata->fixed_screen_cpu) {
        fbi->map_size = PAGE_ALIGN(info->fix.smem_len);
        fbi->map_cpu = dma_alloc_writecombine(&pdev->dev,
                fbi->map_size, &fbi->map_dma, GFP_KERNEL);

        if (!fbi->map_cpu) {
            dev_err(&pdev->dev, "Failed to allocate video RAM: %d\n", ret);
            ret = -ENOMEM;
            goto failed_map;
        }

        info->screen_base = fbi->map_cpu;
        fbi->screen_cpu = fbi->map_cpu;
        fbi->screen_dma = fbi->map_dma;
        info->fix.smem_start = fbi->screen_dma;
    } else {
        /* Fixed framebuffer mapping enables location of the screen in eSRAM */
        fbi->map_cpu = pdata->fixed_screen_cpu;
        fbi->map_dma = pdata->fixed_screen_dma;
        info->screen_base = fbi->map_cpu;
        fbi->screen_cpu = fbi->map_cpu;
        fbi->screen_dma = fbi->map_dma;
        info->fix.smem_start = fbi->screen_dma;
    }

    if (pdata->init) {
        ret = pdata->init(fbi->pdev);
        if (ret)
            goto failed_platform_init;
    }

    fbi->mode = pdata->mode;
    fbi->num_modes = pdata->num_modes;

    INIT_LIST_HEAD(&info->modelist);
    for (i = 0; i < pdata->num_modes; i++)
        fb_add_videomode(&pdata->mode[i].mode, &info->modelist);

    /*
     * This makes sure that our colour bitfield
     * descriptors are correctly initialised.
     */
    imxfb_check_var(&info->var, info);

    ret = fb_alloc_cmap(&info->cmap, 1 << info->var.bits_per_pixel, 0);
    if (ret < 0)
        goto failed_cmap;

    imxfb_set_par(info);
    ret = register_framebuffer(info);
    if (ret < 0) {
        dev_err(&pdev->dev, "failed to register framebuffer\n");
        goto failed_register;
    }

    imxfb_enable_controller(fbi);
    fbi->pdev = pdev;
#ifdef PWMR_BACKLIGHT_AVAILABLE
    imxfb_init_backlight(fbi);
#endif

    return 0;

failed_register:
    fb_dealloc_cmap(&info->cmap);
failed_cmap:
    if (pdata->exit)
        pdata->exit(fbi->pdev);
failed_platform_init:
    if (!pdata->fixed_screen_cpu)
        dma_free_writecombine(&pdev->dev,fbi->map_size,fbi->map_cpu,
            fbi->map_dma);
failed_map:
    iounmap(fbi->regs);
failed_ioremap:
failed_getclock:
    release_mem_region(res->start, resource_size(res));
failed_req:
    kfree(info->pseudo_palette);
failed_init:
    platform_set_drvdata(pdev, NULL);
    framebuffer_release(info);
    return ret;
}

static int __devexit imxfb_remove(struct platform_device *pdev)
{
    struct imx_fb_platform_data *pdata;
    struct fb_info *info = platform_get_drvdata(pdev);
    struct imxfb_info *fbi = info->par;
    struct resource *res;

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

    imxfb_disable_controller(fbi);

#ifdef PWMR_BACKLIGHT_AVAILABLE
    imxfb_exit_backlight(fbi);
#endif
    unregister_framebuffer(info);

    pdata = pdev->dev.platform_data;
    if (pdata->exit)
        pdata->exit(fbi->pdev);

    fb_dealloc_cmap(&info->cmap);
    kfree(info->pseudo_palette);
    framebuffer_release(info);

    iounmap(fbi->regs);
    release_mem_region(res->start, resource_size(res));

    platform_set_drvdata(pdev, NULL);

    return 0;
}

void  imxfb_shutdown(struct platform_device * dev)
{
    struct fb_info *info = platform_get_drvdata(dev);
    struct imxfb_info *fbi = info->par;
    imxfb_disable_controller(fbi);
}

static struct platform_driver imxfb_driver = {
    .suspend    = imxfb_suspend,
    .resume     = imxfb_resume,
    .remove     = __devexit_p(imxfb_remove),
    .shutdown   = imxfb_shutdown,
    .driver     = {
        .name   = DRIVER_NAME,
    },
};

static int imxfb_setup(void)
{
#ifndef MODULE
    char *opt, *options = NULL;

    if (fb_get_options("imxfb", &options))
        return -ENODEV;

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

    while ((opt = strsep(&options, ",")) != NULL) {
        if (!*opt)
            continue;
        else
            fb_mode = opt;
    }
#endif
    return 0;
}

int __init imxfb_init(void)
{
    int ret = imxfb_setup();

    if (ret < 0)
        return ret;

    return platform_driver_probe(&imxfb_driver, imxfb_probe);
}

static void __exit imxfb_cleanup(void)
{
    platform_driver_unregister(&imxfb_driver);
}

module_init(imxfb_init);
module_exit(imxfb_cleanup);

MODULE_DESCRIPTION("Freescale i.MX framebuffer driver");
MODULE_AUTHOR("Sascha Hauer, Pengutronix");
MODULE_LICENSE("GPL");