drivers/video/wm8505fb.c - linux/kernel/git/paulmck/linux-rcu - Git at Google

 /*
  *  WonderMedia WM8505 Frame Buffer device driver
  *
  *  Copyright (C) 2010 Ed Spiridonov <edo.rus@gmail.com>
  *    Based on vt8500lcdfb.c
  *
  * This software is licensed under the terms of the GNU General Public
  * License version 2, as published by the Free Software Foundation, and
  * may be copied, distributed, and modified under those terms.
  *
  * 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.
  */

 #include <linux/delay.h>
 #include <linux/dma-mapping.h>
 #include <linux/fb.h>
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/memblock.h>
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/wait.h>
 #include <video/of_display_timing.h>

 #include "wm8505fb_regs.h"
 #include "wmt_ge_rops.h"

 #define DRIVER_NAME "wm8505-fb"

 #define to_wm8505fb_info(__info) container_of(__info, \
 						struct wm8505fb_info, fb)
 struct wm8505fb_info {
 	struct fb_info		fb;
 	void __iomem		*regbase;
 	unsigned int		contrast;
 };


 static int wm8505fb_init_hw(struct fb_info *info)
 {
 	struct wm8505fb_info *fbi = to_wm8505fb_info(info);

 	int i;

 	/* I know the purpose only of few registers, so clear unknown */
 	for (i = 0; i < 0x200; i += 4)
 		writel(0, fbi->regbase + i);

 	/* Set frame buffer address */
 	writel(fbi->fb.fix.smem_start, fbi->regbase + WMT_GOVR_FBADDR);
 	writel(fbi->fb.fix.smem_start, fbi->regbase + WMT_GOVR_FBADDR1);

 	/*
 	 * Set in-memory picture format to RGB
 	 * 0x31C sets the correct color mode (RGB565) for WM8650
 	 * Bit 8+9 (0x300) are ignored on WM8505 as reserved
 	 */
 	writel(0x31c,		       fbi->regbase + WMT_GOVR_COLORSPACE);
 	writel(1,		       fbi->regbase + WMT_GOVR_COLORSPACE1);

 	/* Virtual buffer size */
 	writel(info->var.xres,	       fbi->regbase + WMT_GOVR_XRES);
 	writel(info->var.xres_virtual, fbi->regbase + WMT_GOVR_XRES_VIRTUAL);

 	/* black magic ;) */
 	writel(0xf,		       fbi->regbase + WMT_GOVR_FHI);
 	writel(4,		       fbi->regbase + WMT_GOVR_DVO_SET);
 	writel(1,		       fbi->regbase + WMT_GOVR_MIF_ENABLE);
 	writel(1,		       fbi->regbase + WMT_GOVR_REG_UPDATE);

 	return 0;
 }

 static int wm8505fb_set_timing(struct fb_info *info)
 {
 	struct wm8505fb_info *fbi = to_wm8505fb_info(info);

 	int h_start = info->var.left_margin;
 	int h_end = h_start + info->var.xres;
 	int h_all = h_end + info->var.right_margin;
 	int h_sync = info->var.hsync_len;

 	int v_start = info->var.upper_margin;
 	int v_end = v_start + info->var.yres;
 	int v_all = v_end + info->var.lower_margin;
 	int v_sync = info->var.vsync_len;

 	writel(0, fbi->regbase + WMT_GOVR_TG);

 	writel(h_start, fbi->regbase + WMT_GOVR_TIMING_H_START);
 	writel(h_end,   fbi->regbase + WMT_GOVR_TIMING_H_END);
 	writel(h_all,   fbi->regbase + WMT_GOVR_TIMING_H_ALL);
 	writel(h_sync,  fbi->regbase + WMT_GOVR_TIMING_H_SYNC);

 	writel(v_start, fbi->regbase + WMT_GOVR_TIMING_V_START);
 	writel(v_end,   fbi->regbase + WMT_GOVR_TIMING_V_END);
 	writel(v_all,   fbi->regbase + WMT_GOVR_TIMING_V_ALL);
 	writel(v_sync,  fbi->regbase + WMT_GOVR_TIMING_V_SYNC);

 	writel(1, fbi->regbase + WMT_GOVR_TG);

 	return 0;
 }


 static int wm8505fb_set_par(struct fb_info *info)
 {
 	struct wm8505fb_info *fbi = to_wm8505fb_info(info);

 	if (!fbi)
 		return -EINVAL;

 	if (info->var.bits_per_pixel == 32) {
 		info->var.red.offset = 16;
 		info->var.red.length = 8;
 		info->var.red.msb_right = 0;
 		info->var.green.offset = 8;
 		info->var.green.length = 8;
 		info->var.green.msb_right = 0;
 		info->var.blue.offset = 0;
 		info->var.blue.length = 8;
 		info->var.blue.msb_right = 0;
 		info->fix.visual = FB_VISUAL_TRUECOLOR;
 		info->fix.line_length = info->var.xres_virtual << 2;
 	} else if (info->var.bits_per_pixel == 16) {
 		info->var.red.offset = 11;
 		info->var.red.length = 5;
 		info->var.red.msb_right = 0;
 		info->var.green.offset = 5;
 		info->var.green.length = 6;
 		info->var.green.msb_right = 0;
 		info->var.blue.offset = 0;
 		info->var.blue.length = 5;
 		info->var.blue.msb_right = 0;
 		info->fix.visual = FB_VISUAL_TRUECOLOR;
 		info->fix.line_length = info->var.xres_virtual << 1;
 	}

 	wm8505fb_set_timing(info);

 	writel(fbi->contrast<<16 | fbi->contrast<<8 | fbi->contrast,
 		fbi->regbase + WMT_GOVR_CONTRAST);

 	return 0;
 }

 static ssize_t contrast_show(struct device *dev,
 			     struct device_attribute *attr, char *buf)
 {
 	struct fb_info *info = dev_get_drvdata(dev);
 	struct wm8505fb_info *fbi = to_wm8505fb_info(info);

 	return sprintf(buf, "%d\n", fbi->contrast);
 }

 static ssize_t contrast_store(struct device *dev,
 			      struct device_attribute *attr,
 			      const char *buf, size_t count)
 {
 	struct fb_info *info = dev_get_drvdata(dev);
 	struct wm8505fb_info *fbi = to_wm8505fb_info(info);
 	unsigned long tmp;

 	if (kstrtoul(buf, 10, &tmp) || (tmp > 0xff))
 		return -EINVAL;
 	fbi->contrast = tmp;

 	wm8505fb_set_par(info);

 	return count;
 }

 static DEVICE_ATTR(contrast, 0644, contrast_show, contrast_store);

 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 wm8505fb_setcolreg(unsigned regno, unsigned red, unsigned green,
 			   unsigned blue, unsigned transp,
 			   struct fb_info *info) {
 	struct wm8505fb_info *fbi = to_wm8505fb_info(info);
 	int ret = 1;
 	unsigned int val;
 	if (regno >= 256)
 		return -EINVAL;

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

 	switch (fbi->fb.fix.visual) {
 	case FB_VISUAL_TRUECOLOR:
 		if (regno < 16) {
 			u32 *pal = info->pseudo_palette;

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

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

 	return ret;
 }

 static int wm8505fb_pan_display(struct fb_var_screeninfo *var,
 				struct fb_info *info)
 {
 	struct wm8505fb_info *fbi = to_wm8505fb_info(info);

 	writel(var->xoffset, fbi->regbase + WMT_GOVR_XPAN);
 	writel(var->yoffset, fbi->regbase + WMT_GOVR_YPAN);
 	return 0;
 }

 static int wm8505fb_blank(int blank, struct fb_info *info)
 {
 	struct wm8505fb_info *fbi = to_wm8505fb_info(info);

 	switch (blank) {
 	case FB_BLANK_UNBLANK:
 		wm8505fb_set_timing(info);
 		break;
 	default:
 		writel(0,  fbi->regbase + WMT_GOVR_TIMING_V_SYNC);
 		break;
 	}

 	return 0;
 }

 static struct fb_ops wm8505fb_ops = {
 	.owner		= THIS_MODULE,
 	.fb_set_par	= wm8505fb_set_par,
 	.fb_setcolreg	= wm8505fb_setcolreg,
 	.fb_fillrect	= wmt_ge_fillrect,
 	.fb_copyarea	= wmt_ge_copyarea,
 	.fb_imageblit	= sys_imageblit,
 	.fb_sync	= wmt_ge_sync,
 	.fb_pan_display	= wm8505fb_pan_display,
 	.fb_blank	= wm8505fb_blank,
 };

 static int wm8505fb_probe(struct platform_device *pdev)
 {
 	struct wm8505fb_info	*fbi;
 	struct resource	*res;
 	struct display_timings *disp_timing;
 	void			*addr;
 	int ret;

 	struct fb_videomode	mode;
 	u32			bpp;
 	dma_addr_t fb_mem_phys;
 	unsigned long fb_mem_len;
 	void *fb_mem_virt;

 	fbi = devm_kzalloc(&pdev->dev, sizeof(struct wm8505fb_info) +
 			sizeof(u32) * 16, GFP_KERNEL);
 	if (!fbi) {
 		dev_err(&pdev->dev, "Failed to initialize framebuffer device\n");
 		return -ENOMEM;
 	}

 	strcpy(fbi->fb.fix.id, DRIVER_NAME);

 	fbi->fb.fix.type	= FB_TYPE_PACKED_PIXELS;
 	fbi->fb.fix.xpanstep	= 1;
 	fbi->fb.fix.ypanstep	= 1;
 	fbi->fb.fix.ywrapstep	= 0;
 	fbi->fb.fix.accel	= FB_ACCEL_NONE;

 	fbi->fb.fbops		= &wm8505fb_ops;
 	fbi->fb.flags		= FBINFO_DEFAULT
 				| FBINFO_HWACCEL_COPYAREA
 				| FBINFO_HWACCEL_FILLRECT
 				| FBINFO_HWACCEL_XPAN
 				| FBINFO_HWACCEL_YPAN
 				| FBINFO_VIRTFB
 				| FBINFO_PARTIAL_PAN_OK;
 	fbi->fb.node		= -1;

 	addr = fbi;
 	addr = addr + sizeof(struct wm8505fb_info);
 	fbi->fb.pseudo_palette	= addr;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	fbi->regbase = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(fbi->regbase))
 		return PTR_ERR(fbi->regbase);

 	disp_timing = of_get_display_timings(pdev->dev.of_node);
 	if (!disp_timing)
 		return -EINVAL;

 	ret = of_get_fb_videomode(pdev->dev.of_node, &mode, OF_USE_NATIVE_MODE);
 	if (ret)
 		return ret;

 	ret = of_property_read_u32(pdev->dev.of_node, "bits-per-pixel", &bpp);
 	if (ret)
 		return ret;

 	fb_videomode_to_var(&fbi->fb.var, &mode);

 	fbi->fb.var.nonstd		= 0;
 	fbi->fb.var.activate		= FB_ACTIVATE_NOW;

 	fbi->fb.var.height		= -1;
 	fbi->fb.var.width		= -1;

 	/* try allocating the framebuffer */
 	fb_mem_len = mode.xres * mode.yres * 2 * (bpp / 8);
 	fb_mem_virt = dmam_alloc_coherent(&pdev->dev, fb_mem_len, &fb_mem_phys,
 				GFP_KERNEL);
 	if (!fb_mem_virt) {
 		pr_err("%s: Failed to allocate framebuffer\n", __func__);
 		return -ENOMEM;
 	}

 	fbi->fb.var.xres_virtual	= mode.xres;
 	fbi->fb.var.yres_virtual	= mode.yres * 2;
 	fbi->fb.var.bits_per_pixel	= bpp;

 	fbi->fb.fix.smem_start		= fb_mem_phys;
 	fbi->fb.fix.smem_len		= fb_mem_len;
 	fbi->fb.screen_base		= fb_mem_virt;
 	fbi->fb.screen_size		= fb_mem_len;

 	fbi->contrast = 0x10;
 	ret = wm8505fb_set_par(&fbi->fb);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to set parameters\n");
 		return ret;
 	}

 	if (fb_alloc_cmap(&fbi->fb.cmap, 256, 0) < 0) {
 		dev_err(&pdev->dev, "Failed to allocate color map\n");
 		return -ENOMEM;
 	}

 	wm8505fb_init_hw(&fbi->fb);

 	platform_set_drvdata(pdev, fbi);

 	ret = register_framebuffer(&fbi->fb);
 	if (ret < 0) {
 		dev_err(&pdev->dev,
 			"Failed to register framebuffer device: %d\n", ret);
 		if (fbi->fb.cmap.len)
 			fb_dealloc_cmap(&fbi->fb.cmap);
 		return ret;
 	}

 	ret = device_create_file(&pdev->dev, &dev_attr_contrast);
 	if (ret < 0)
 		fb_warn(&fbi->fb, "failed to register attributes (%d)\n", ret);

 	fb_info(&fbi->fb, "%s frame buffer at 0x%lx-0x%lx\n",
 		fbi->fb.fix.id, fbi->fb.fix.smem_start,
 		fbi->fb.fix.smem_start + fbi->fb.fix.smem_len - 1);

 	return 0;
 }

 static int wm8505fb_remove(struct platform_device *pdev)
 {
 	struct wm8505fb_info *fbi = platform_get_drvdata(pdev);

 	device_remove_file(&pdev->dev, &dev_attr_contrast);

 	unregister_framebuffer(&fbi->fb);

 	writel(0, fbi->regbase);

 	if (fbi->fb.cmap.len)
 		fb_dealloc_cmap(&fbi->fb.cmap);

 	return 0;
 }

 static const struct of_device_id wmt_dt_ids[] = {
 	{ .compatible = "wm,wm8505-fb", },
 	{}
 };

 static struct platform_driver wm8505fb_driver = {
 	.probe		= wm8505fb_probe,
 	.remove		= wm8505fb_remove,
 	.driver		= {
 		.owner	= THIS_MODULE,
 		.name	= DRIVER_NAME,
 		.of_match_table = wmt_dt_ids,
 	},
 };

 module_platform_driver(wm8505fb_driver);

 MODULE_AUTHOR("Ed Spiridonov <edo.rus@gmail.com>");
 MODULE_DESCRIPTION("Framebuffer driver for WMT WM8505");
 MODULE_LICENSE("GPL v2");
 MODULE_DEVICE_TABLE(of, wmt_dt_ids);
	/*
	* WonderMedia WM8505 Frame Buffer device driver
	*
	* Copyright (C) 2010 Ed Spiridonov <edo.rus@gmail.com>
	* Based on vt8500lcdfb.c
	*
	* This software is licensed under the terms of the GNU General Public
	* License version 2, as published by the Free Software Foundation, and
	* may be copied, distributed, and modified under those terms.
	*
	* 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.
	*/

	#include <linux/delay.h>
	#include <linux/dma-mapping.h>
	#include <linux/fb.h>
	#include <linux/errno.h>
	#include <linux/err.h>
	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/memblock.h>
	#include <linux/mm.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_fdt.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>
	#include <linux/string.h>
	#include <linux/wait.h>
	#include <video/of_display_timing.h>

	#include "wm8505fb_regs.h"
	#include "wmt_ge_rops.h"

	#define DRIVER_NAME "wm8505-fb"

	#define to_wm8505fb_info(__info) container_of(__info, \
	struct wm8505fb_info, fb)
	struct wm8505fb_info {
	struct fb_info fb;
	void __iomem *regbase;
	unsigned int contrast;
	};


	static int wm8505fb_init_hw(struct fb_info *info)
	{
	struct wm8505fb_info *fbi = to_wm8505fb_info(info);

	int i;

	/* I know the purpose only of few registers, so clear unknown */
	for (i = 0; i < 0x200; i += 4)
	writel(0, fbi->regbase + i);

	/* Set frame buffer address */
	writel(fbi->fb.fix.smem_start, fbi->regbase + WMT_GOVR_FBADDR);
	writel(fbi->fb.fix.smem_start, fbi->regbase + WMT_GOVR_FBADDR1);

	/*
	* Set in-memory picture format to RGB
	* 0x31C sets the correct color mode (RGB565) for WM8650
	* Bit 8+9 (0x300) are ignored on WM8505 as reserved
	*/
	writel(0x31c, fbi->regbase + WMT_GOVR_COLORSPACE);
	writel(1, fbi->regbase + WMT_GOVR_COLORSPACE1);

	/* Virtual buffer size */
	writel(info->var.xres, fbi->regbase + WMT_GOVR_XRES);
	writel(info->var.xres_virtual, fbi->regbase + WMT_GOVR_XRES_VIRTUAL);

	/* black magic ;) */
	writel(0xf, fbi->regbase + WMT_GOVR_FHI);
	writel(4, fbi->regbase + WMT_GOVR_DVO_SET);
	writel(1, fbi->regbase + WMT_GOVR_MIF_ENABLE);
	writel(1, fbi->regbase + WMT_GOVR_REG_UPDATE);

	return 0;
	}

	static int wm8505fb_set_timing(struct fb_info *info)
	{
	struct wm8505fb_info *fbi = to_wm8505fb_info(info);

	int h_start = info->var.left_margin;
	int h_end = h_start + info->var.xres;
	int h_all = h_end + info->var.right_margin;
	int h_sync = info->var.hsync_len;

	int v_start = info->var.upper_margin;
	int v_end = v_start + info->var.yres;
	int v_all = v_end + info->var.lower_margin;
	int v_sync = info->var.vsync_len;

	writel(0, fbi->regbase + WMT_GOVR_TG);

	writel(h_start, fbi->regbase + WMT_GOVR_TIMING_H_START);
	writel(h_end, fbi->regbase + WMT_GOVR_TIMING_H_END);
	writel(h_all, fbi->regbase + WMT_GOVR_TIMING_H_ALL);
	writel(h_sync, fbi->regbase + WMT_GOVR_TIMING_H_SYNC);

	writel(v_start, fbi->regbase + WMT_GOVR_TIMING_V_START);
	writel(v_end, fbi->regbase + WMT_GOVR_TIMING_V_END);
	writel(v_all, fbi->regbase + WMT_GOVR_TIMING_V_ALL);
	writel(v_sync, fbi->regbase + WMT_GOVR_TIMING_V_SYNC);

	writel(1, fbi->regbase + WMT_GOVR_TG);

	return 0;
	}


	static int wm8505fb_set_par(struct fb_info *info)
	{
	struct wm8505fb_info *fbi = to_wm8505fb_info(info);

	if (!fbi)
	return -EINVAL;

	if (info->var.bits_per_pixel == 32) {
	info->var.red.offset = 16;
	info->var.red.length = 8;
	info->var.red.msb_right = 0;
	info->var.green.offset = 8;
	info->var.green.length = 8;
	info->var.green.msb_right = 0;
	info->var.blue.offset = 0;
	info->var.blue.length = 8;
	info->var.blue.msb_right = 0;
	info->fix.visual = FB_VISUAL_TRUECOLOR;
	info->fix.line_length = info->var.xres_virtual << 2;
	} else if (info->var.bits_per_pixel == 16) {
	info->var.red.offset = 11;
	info->var.red.length = 5;
	info->var.red.msb_right = 0;
	info->var.green.offset = 5;
	info->var.green.length = 6;
	info->var.green.msb_right = 0;
	info->var.blue.offset = 0;
	info->var.blue.length = 5;
	info->var.blue.msb_right = 0;
	info->fix.visual = FB_VISUAL_TRUECOLOR;
	info->fix.line_length = info->var.xres_virtual << 1;
	}

	wm8505fb_set_timing(info);

	writel(fbi->contrast<<16 \| fbi->contrast<<8 \| fbi->contrast,
	fbi->regbase + WMT_GOVR_CONTRAST);

	return 0;
	}

	static ssize_t contrast_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct fb_info *info = dev_get_drvdata(dev);
	struct wm8505fb_info *fbi = to_wm8505fb_info(info);

	return sprintf(buf, "%d\n", fbi->contrast);
	}

	static ssize_t contrast_store(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t count)
	{
	struct fb_info *info = dev_get_drvdata(dev);
	struct wm8505fb_info *fbi = to_wm8505fb_info(info);
	unsigned long tmp;

	if (kstrtoul(buf, 10, &tmp) \|\| (tmp > 0xff))
	return -EINVAL;
	fbi->contrast = tmp;

	wm8505fb_set_par(info);

	return count;
	}

	static DEVICE_ATTR(contrast, 0644, contrast_show, contrast_store);

	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 wm8505fb_setcolreg(unsigned regno, unsigned red, unsigned green,
	unsigned blue, unsigned transp,
	struct fb_info *info) {
	struct wm8505fb_info *fbi = to_wm8505fb_info(info);
	int ret = 1;
	unsigned int val;
	if (regno >= 256)
	return -EINVAL;

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

	switch (fbi->fb.fix.visual) {
	case FB_VISUAL_TRUECOLOR:
	if (regno < 16) {
	u32 *pal = info->pseudo_palette;

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

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

	return ret;
	}

	static int wm8505fb_pan_display(struct fb_var_screeninfo *var,
	struct fb_info *info)
	{
	struct wm8505fb_info *fbi = to_wm8505fb_info(info);

	writel(var->xoffset, fbi->regbase + WMT_GOVR_XPAN);
	writel(var->yoffset, fbi->regbase + WMT_GOVR_YPAN);
	return 0;
	}

	static int wm8505fb_blank(int blank, struct fb_info *info)
	{
	struct wm8505fb_info *fbi = to_wm8505fb_info(info);

	switch (blank) {
	case FB_BLANK_UNBLANK:
	wm8505fb_set_timing(info);
	break;
	default:
	writel(0, fbi->regbase + WMT_GOVR_TIMING_V_SYNC);
	break;
	}

	return 0;
	}

	static struct fb_ops wm8505fb_ops = {
	.owner = THIS_MODULE,
	.fb_set_par = wm8505fb_set_par,
	.fb_setcolreg = wm8505fb_setcolreg,
	.fb_fillrect = wmt_ge_fillrect,
	.fb_copyarea = wmt_ge_copyarea,
	.fb_imageblit = sys_imageblit,
	.fb_sync = wmt_ge_sync,
	.fb_pan_display = wm8505fb_pan_display,
	.fb_blank = wm8505fb_blank,
	};

	static int wm8505fb_probe(struct platform_device *pdev)
	{
	struct wm8505fb_info *fbi;
	struct resource *res;
	struct display_timings *disp_timing;
	void *addr;
	int ret;

	struct fb_videomode mode;
	u32 bpp;
	dma_addr_t fb_mem_phys;
	unsigned long fb_mem_len;
	void *fb_mem_virt;

	fbi = devm_kzalloc(&pdev->dev, sizeof(struct wm8505fb_info) +
	sizeof(u32) * 16, GFP_KERNEL);
	if (!fbi) {
	dev_err(&pdev->dev, "Failed to initialize framebuffer device\n");
	return -ENOMEM;
	}

	strcpy(fbi->fb.fix.id, DRIVER_NAME);

	fbi->fb.fix.type = FB_TYPE_PACKED_PIXELS;
	fbi->fb.fix.xpanstep = 1;
	fbi->fb.fix.ypanstep = 1;
	fbi->fb.fix.ywrapstep = 0;
	fbi->fb.fix.accel = FB_ACCEL_NONE;

	fbi->fb.fbops = &wm8505fb_ops;
	fbi->fb.flags = FBINFO_DEFAULT
	\| FBINFO_HWACCEL_COPYAREA
	\| FBINFO_HWACCEL_FILLRECT
	\| FBINFO_HWACCEL_XPAN
	\| FBINFO_HWACCEL_YPAN
	\| FBINFO_VIRTFB
	\| FBINFO_PARTIAL_PAN_OK;
	fbi->fb.node = -1;

	addr = fbi;
	addr = addr + sizeof(struct wm8505fb_info);
	fbi->fb.pseudo_palette = addr;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	fbi->regbase = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(fbi->regbase))
	return PTR_ERR(fbi->regbase);

	disp_timing = of_get_display_timings(pdev->dev.of_node);
	if (!disp_timing)
	return -EINVAL;

	ret = of_get_fb_videomode(pdev->dev.of_node, &mode, OF_USE_NATIVE_MODE);
	if (ret)
	return ret;

	ret = of_property_read_u32(pdev->dev.of_node, "bits-per-pixel", &bpp);
	if (ret)
	return ret;

	fb_videomode_to_var(&fbi->fb.var, &mode);

	fbi->fb.var.nonstd = 0;
	fbi->fb.var.activate = FB_ACTIVATE_NOW;

	fbi->fb.var.height = -1;
	fbi->fb.var.width = -1;

	/* try allocating the framebuffer */
	fb_mem_len = mode.xres * mode.yres * 2 * (bpp / 8);
	fb_mem_virt = dmam_alloc_coherent(&pdev->dev, fb_mem_len, &fb_mem_phys,
	GFP_KERNEL);
	if (!fb_mem_virt) {
	pr_err("%s: Failed to allocate framebuffer\n", __func__);
	return -ENOMEM;
	}

	fbi->fb.var.xres_virtual = mode.xres;
	fbi->fb.var.yres_virtual = mode.yres * 2;
	fbi->fb.var.bits_per_pixel = bpp;

	fbi->fb.fix.smem_start = fb_mem_phys;
	fbi->fb.fix.smem_len = fb_mem_len;
	fbi->fb.screen_base = fb_mem_virt;
	fbi->fb.screen_size = fb_mem_len;

	fbi->contrast = 0x10;
	ret = wm8505fb_set_par(&fbi->fb);
	if (ret) {
	dev_err(&pdev->dev, "Failed to set parameters\n");
	return ret;
	}

	if (fb_alloc_cmap(&fbi->fb.cmap, 256, 0) < 0) {
	dev_err(&pdev->dev, "Failed to allocate color map\n");
	return -ENOMEM;
	}

	wm8505fb_init_hw(&fbi->fb);

	platform_set_drvdata(pdev, fbi);

	ret = register_framebuffer(&fbi->fb);
	if (ret < 0) {
	dev_err(&pdev->dev,
	"Failed to register framebuffer device: %d\n", ret);
	if (fbi->fb.cmap.len)
	fb_dealloc_cmap(&fbi->fb.cmap);
	return ret;
	}

	ret = device_create_file(&pdev->dev, &dev_attr_contrast);
	if (ret < 0)
	fb_warn(&fbi->fb, "failed to register attributes (%d)\n", ret);

	fb_info(&fbi->fb, "%s frame buffer at 0x%lx-0x%lx\n",
	fbi->fb.fix.id, fbi->fb.fix.smem_start,
	fbi->fb.fix.smem_start + fbi->fb.fix.smem_len - 1);

	return 0;
	}

	static int wm8505fb_remove(struct platform_device *pdev)
	{
	struct wm8505fb_info *fbi = platform_get_drvdata(pdev);

	device_remove_file(&pdev->dev, &dev_attr_contrast);

	unregister_framebuffer(&fbi->fb);

	writel(0, fbi->regbase);

	if (fbi->fb.cmap.len)
	fb_dealloc_cmap(&fbi->fb.cmap);

	return 0;
	}

	static const struct of_device_id wmt_dt_ids[] = {
	{ .compatible = "wm,wm8505-fb", },
	{}
	};

	static struct platform_driver wm8505fb_driver = {
	.probe = wm8505fb_probe,
	.remove = wm8505fb_remove,
	.driver = {
	.owner = THIS_MODULE,
	.name = DRIVER_NAME,
	.of_match_table = wmt_dt_ids,
	},
	};

	module_platform_driver(wm8505fb_driver);

	MODULE_AUTHOR("Ed Spiridonov <edo.rus@gmail.com>");
	MODULE_DESCRIPTION("Framebuffer driver for WMT WM8505");
	MODULE_LICENSE("GPL v2");
	MODULE_DEVICE_TABLE(of, wmt_dt_ids);