ep93xx video driver (88017bda) · Commits · e / devices / android_kernel_teracube_emerald

Documentation/fb/ep93xx-fb.txt

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			================================
			Driver for EP93xx LCD controller
			================================

			The EP93xx LCD controller can drive both standard desktop monitors and
			embedded LCD displays. If you have a standard desktop monitor then you
			can use the standard Linux video mode database. In your board file:

			static struct ep93xxfb_mach_info some_board_fb_info = {
			.num_modes = EP93XXFB_USE_MODEDB,
			.bpp = 16,
			};

			If you have an embedded LCD display then you need to define a video
			mode for it as follows:

			static struct fb_videomode some_board_video_modes[] = {
			{
			.name = "some_lcd_name",
			/* Pixel clock, porches, etc */
			},
			};

			Note that the pixel clock value is in pico-seconds. You can use the
			KHZ2PICOS macro to convert the pixel clock value. Most other values
			are in pixel clocks. See Documentation/fb/framebuffer.txt for further
			details.

			The ep93xxfb_mach_info structure for your board should look like the
			following:

			static struct ep93xxfb_mach_info some_board_fb_info = {
			.num_modes = ARRAY_SIZE(some_board_video_modes),
			.modes = some_board_video_modes,
			.default_mode = &some_board_video_modes[0],
			.bpp = 16,
			};

			The framebuffer device can be registered by adding the following to
			your board initialisation function:

			ep93xx_register_fb(&some_board_fb_info);

			=====================
			Video Attribute Flags
			=====================

			The ep93xxfb_mach_info structure has a flags field which can be used
			to configure the controller. The video attributes flags are fully
			documented in section 7 of the EP93xx users' guide. The following
			flags are available:

			EP93XXFB_PCLK_FALLING Clock data on the falling edge of the
			pixel clock. The default is to clock
			data on the rising edge.

			EP93XXFB_SYNC_BLANK_HIGH Blank signal is active high. By
			default the blank signal is active low.

			EP93XXFB_SYNC_HORIZ_HIGH Horizontal sync is active high. By
			default the horizontal sync is active low.

			EP93XXFB_SYNC_VERT_HIGH Vertical sync is active high. By
			default the vertical sync is active high.

			The physical address of the framebuffer can be controlled using the
			following flags:

			EP93XXFB_USE_SDCSN0 Use SDCSn[0] for the framebuffer. This
			is the default setting.

			EP93XXFB_USE_SDCSN1 Use SDCSn[1] for the framebuffer.

			EP93XXFB_USE_SDCSN2 Use SDCSn[2] for the framebuffer.

			EP93XXFB_USE_SDCSN3 Use SDCSn[3] for the framebuffer.

			==================
			Platform callbacks
			==================

			The EP93xx framebuffer driver supports three optional platform
			callbacks: setup, teardown and blank. The setup and teardown functions
			are called when the framebuffer driver is installed and removed
			respectively. The blank function is called whenever the display is
			blanked or unblanked.

			The setup and teardown devices pass the platform_device structure as
			an argument. The fb_info and ep93xxfb_mach_info structures can be
			obtained as follows:

			static int some_board_fb_setup(struct platform_device *pdev)
			{
			struct ep93xxfb_mach_info *mach_info = pdev->dev.platform_data;
			struct fb_info *fb_info = platform_get_drvdata(pdev);

			/* Board specific framebuffer setup */
			}

			======================
			Setting the video mode
			======================

			The video mode is set using the following syntax:

			video=XRESxYRES[-BPP][@REFRESH]

			If the EP93xx video driver is built-in then the video mode is set on
			the Linux kernel command line, for example:

			video=ep93xx-fb:800x600-16@60

			If the EP93xx video driver is built as a module then the video mode is
			set when the module is installed:

			modprobe ep93xx-fb video=320x240

			==============
			Screenpage bug
			==============

			At least on the EP9315 there is a silicon bug which causes bit 27 of
			the VIDSCRNPAGE (framebuffer physical offset) to be tied low. There is
			an unofficial errata for this bug at:
			http://marc.info/?l=linux-arm-kernel&m=110061245502000&w=2

			By default the EP93xx framebuffer driver checks if the allocated physical
			address has bit 27 set. If it does, then the memory is freed and an
			error is returned. The check can be disabled by adding the following
			option when loading the driver:

			ep93xx-fb.check_screenpage_bug=0

			In some cases it may be possible to reconfigure your SDRAM layout to
			avoid this bug. See section 13 of the EP93xx users' guide for details.

drivers/video/Kconfig

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	@@ -2128,6 +2128,17 @@ config FB_MB862XX_LIME
	---help---		---help---
	Framebuffer support for Fujitsu Lime GDC on host CPU bus.		Framebuffer support for Fujitsu Lime GDC on host CPU bus.

			config FB_EP93XX
			tristate "EP93XX frame buffer support"
			depends on FB && ARCH_EP93XX
			select FB_CFB_FILLRECT
			select FB_CFB_COPYAREA
			select FB_CFB_IMAGEBLIT
			---help---
			Framebuffer driver for the Cirrus Logic EP93XX series of processors.
			This driver is also available as a module. The module will be called
			ep93xx-fb.

	config FB_PRE_INIT_FB		config FB_PRE_INIT_FB
	bool "Don't reinitialize, use bootloader's GDC/Display configuration"		bool "Don't reinitialize, use bootloader's GDC/Display configuration"
	depends on FB_MB862XX_LIME		depends on FB_MB862XX_LIME

drivers/video/Makefile

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	@@ -85,6 +85,7 @@ obj-$(CONFIG_FB_Q40) += q40fb.o
	obj-$(CONFIG_FB_TGA) += tgafb.o		obj-$(CONFIG_FB_TGA) += tgafb.o
	obj-$(CONFIG_FB_HP300) += hpfb.o		obj-$(CONFIG_FB_HP300) += hpfb.o
	obj-$(CONFIG_FB_G364) += g364fb.o		obj-$(CONFIG_FB_G364) += g364fb.o
			obj-$(CONFIG_FB_EP93XX) += ep93xx-fb.o
	obj-$(CONFIG_FB_SA1100) += sa1100fb.o		obj-$(CONFIG_FB_SA1100) += sa1100fb.o
	obj-$(CONFIG_FB_HIT) += hitfb.o		obj-$(CONFIG_FB_HIT) += hitfb.o
	obj-$(CONFIG_FB_EPSON1355) += epson1355fb.o		obj-$(CONFIG_FB_EPSON1355) += epson1355fb.o

drivers/video/ep93xx-fb.c

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			/*
			* linux/drivers/video/ep93xx-fb.c
			*
			* Framebuffer support for the EP93xx series.
			*
			* Copyright (C) 2007 Bluewater Systems Ltd
			* Author: Ryan Mallon <ryan@bluewatersys.com>
			*
			* Copyright (c) 2009 H Hartley Sweeten <hsweeten@visionengravers.com>
			*
			* Based on the Cirrus Logic ep93xxfb driver, and various other ep93xxfb
			* drivers.
			*
			* This program is free software; you can redistribute it and/or modify
			* it under the terms of the GNU General Public License version 2 as
			* published by the Free Software Foundation.
			*
			*/

			#include <linux/platform_device.h>
			#include <linux/dma-mapping.h>
			#include <linux/clk.h>
			#include <linux/fb.h>

			#include <mach/fb.h>

			/* Vertical Frame Timing Registers */
			#define EP93XXFB_VLINES_TOTAL 0x0000 /* SW locked */
			#define EP93XXFB_VSYNC 0x0004 /* SW locked */
			#define EP93XXFB_VACTIVE 0x0008 /* SW locked */
			#define EP93XXFB_VBLANK 0x0228 /* SW locked */
			#define EP93XXFB_VCLK 0x000c /* SW locked */

			/* Horizontal Frame Timing Registers */
			#define EP93XXFB_HCLKS_TOTAL 0x0010 /* SW locked */
			#define EP93XXFB_HSYNC 0x0014 /* SW locked */
			#define EP93XXFB_HACTIVE 0x0018 /* SW locked */
			#define EP93XXFB_HBLANK 0x022c /* SW locked */
			#define EP93XXFB_HCLK 0x001c /* SW locked */

			/* Frame Buffer Memory Configuration Registers */
			#define EP93XXFB_SCREEN_PAGE 0x0028
			#define EP93XXFB_SCREEN_HPAGE 0x002c
			#define EP93XXFB_SCREEN_LINES 0x0030
			#define EP93XXFB_LINE_LENGTH 0x0034
			#define EP93XXFB_VLINE_STEP 0x0038
			#define EP93XXFB_LINE_CARRY 0x003c /* SW locked */
			#define EP93XXFB_EOL_OFFSET 0x0230

			/* Other Video Registers */
			#define EP93XXFB_BRIGHTNESS 0x0020
			#define EP93XXFB_ATTRIBS 0x0024 /* SW locked */
			#define EP93XXFB_SWLOCK 0x007c /* SW locked */
			#define EP93XXFB_AC_RATE 0x0214
			#define EP93XXFB_FIFO_LEVEL 0x0234
			#define EP93XXFB_PIXELMODE 0x0054
			#define EP93XXFB_PIXELMODE_32BPP (0x7 << 0)
			#define EP93XXFB_PIXELMODE_24BPP (0x6 << 0)
			#define EP93XXFB_PIXELMODE_16BPP (0x4 << 0)
			#define EP93XXFB_PIXELMODE_8BPP (0x2 << 0)
			#define EP93XXFB_PIXELMODE_SHIFT_1P_24B (0x0 << 3)
			#define EP93XXFB_PIXELMODE_SHIFT_1P_18B (0x1 << 3)
			#define EP93XXFB_PIXELMODE_COLOR_LUT (0x0 << 10)
			#define EP93XXFB_PIXELMODE_COLOR_888 (0x4 << 10)
			#define EP93XXFB_PIXELMODE_COLOR_555 (0x5 << 10)
			#define EP93XXFB_PARL_IF_OUT 0x0058
			#define EP93XXFB_PARL_IF_IN 0x005c

			/* Blink Control Registers */
			#define EP93XXFB_BLINK_RATE 0x0040
			#define EP93XXFB_BLINK_MASK 0x0044
			#define EP93XXFB_BLINK_PATTRN 0x0048
			#define EP93XXFB_PATTRN_MASK 0x004c
			#define EP93XXFB_BKGRND_OFFSET 0x0050

			/* Hardware Cursor Registers */
			#define EP93XXFB_CURSOR_ADR_START 0x0060
			#define EP93XXFB_CURSOR_ADR_RESET 0x0064
			#define EP93XXFB_CURSOR_SIZE 0x0068
			#define EP93XXFB_CURSOR_COLOR1 0x006c
			#define EP93XXFB_CURSOR_COLOR2 0x0070
			#define EP93XXFB_CURSOR_BLINK_COLOR1 0x021c
			#define EP93XXFB_CURSOR_BLINK_COLOR2 0x0220
			#define EP93XXFB_CURSOR_XY_LOC 0x0074
			#define EP93XXFB_CURSOR_DSCAN_HY_LOC 0x0078
			#define EP93XXFB_CURSOR_BLINK_RATE_CTRL 0x0224

			/* LUT Registers */
			#define EP93XXFB_GRY_SCL_LUTR 0x0080
			#define EP93XXFB_GRY_SCL_LUTG 0x0280
			#define EP93XXFB_GRY_SCL_LUTB 0x0300
			#define EP93XXFB_LUT_SW_CONTROL 0x0218
			#define EP93XXFB_LUT_SW_CONTROL_SWTCH (1 << 0)
			#define EP93XXFB_LUT_SW_CONTROL_SSTAT (1 << 1)
			#define EP93XXFB_COLOR_LUT 0x0400

			/* Video Signature Registers */
			#define EP93XXFB_VID_SIG_RSLT_VAL 0x0200
			#define EP93XXFB_VID_SIG_CTRL 0x0204
			#define EP93XXFB_VSIG 0x0208
			#define EP93XXFB_HSIG 0x020c
			#define EP93XXFB_SIG_CLR_STR 0x0210

			/* Minimum / Maximum resolutions supported */
			#define EP93XXFB_MIN_XRES 64
			#define EP93XXFB_MIN_YRES 64
			#define EP93XXFB_MAX_XRES 1024
			#define EP93XXFB_MAX_YRES 768

			struct ep93xx_fbi {
			struct ep93xxfb_mach_info *mach_info;
			struct clk *clk;
			struct resource *res;
			void __iomem *mmio_base;
			unsigned int pseudo_palette[256];
			};

			static int check_screenpage_bug = 1;
			module_param(check_screenpage_bug, int, 0644);
			MODULE_PARM_DESC(check_screenpage_bug,
			"Check for bit 27 screen page bug. Default = 1");

			static inline unsigned int ep93xxfb_readl(struct ep93xx_fbi *fbi,
			unsigned int off)
			{
			return __raw_readl(fbi->mmio_base + off);
			}

			static inline void ep93xxfb_writel(struct ep93xx_fbi *fbi,
			unsigned int val, unsigned int off)
			{
			__raw_writel(val, fbi->mmio_base + off);
			}

			/*
			* Write to one of the locked raster registers.
			*/
			static inline void ep93xxfb_out_locked(struct ep93xx_fbi *fbi,
			unsigned int val, unsigned int reg)
			{
			/*
			* We don't need a lock or delay here since the raster register
			* block will remain unlocked until the next access.
			*/
			ep93xxfb_writel(fbi, 0xaa, EP93XXFB_SWLOCK);
			ep93xxfb_writel(fbi, val, reg);
			}

			static void ep93xxfb_set_video_attribs(struct fb_info *info)
			{
			struct ep93xx_fbi *fbi = info->par;
			unsigned int attribs;

			attribs = EP93XXFB_ENABLE;
			attribs \|= fbi->mach_info->flags;
			ep93xxfb_out_locked(fbi, attribs, EP93XXFB_ATTRIBS);
			}

			static int ep93xxfb_set_pixelmode(struct fb_info *info)
			{
			struct ep93xx_fbi *fbi = info->par;
			unsigned int val;

			info->var.transp.offset = 0;
			info->var.transp.length = 0;

			switch (info->var.bits_per_pixel) {
			case 8:
			val = EP93XXFB_PIXELMODE_8BPP \| EP93XXFB_PIXELMODE_COLOR_LUT \|
			EP93XXFB_PIXELMODE_SHIFT_1P_18B;

			info->var.red.offset = 0;
			info->var.red.length = 8;
			info->var.green.offset = 0;
			info->var.green.length = 8;
			info->var.blue.offset = 0;
			info->var.blue.length = 8;
			info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
			break;

			case 16:
			val = EP93XXFB_PIXELMODE_16BPP \| EP93XXFB_PIXELMODE_COLOR_555 \|
			EP93XXFB_PIXELMODE_SHIFT_1P_18B;

			info->var.red.offset = 11;
			info->var.red.length = 5;
			info->var.green.offset = 5;
			info->var.green.length = 6;
			info->var.blue.offset = 0;
			info->var.blue.length = 5;
			info->fix.visual = FB_VISUAL_TRUECOLOR;
			break;

			case 24:
			val = EP93XXFB_PIXELMODE_24BPP \| EP93XXFB_PIXELMODE_COLOR_888 \|
			EP93XXFB_PIXELMODE_SHIFT_1P_24B;

			info->var.red.offset = 16;
			info->var.red.length = 8;
			info->var.green.offset = 8;
			info->var.green.length = 8;
			info->var.blue.offset = 0;
			info->var.blue.length = 8;
			info->fix.visual = FB_VISUAL_TRUECOLOR;
			break;

			case 32:
			val = EP93XXFB_PIXELMODE_32BPP \| EP93XXFB_PIXELMODE_COLOR_888 \|
			EP93XXFB_PIXELMODE_SHIFT_1P_24B;

			info->var.red.offset = 16;
			info->var.red.length = 8;
			info->var.green.offset = 8;
			info->var.green.length = 8;
			info->var.blue.offset = 0;
			info->var.blue.length = 8;
			info->fix.visual = FB_VISUAL_TRUECOLOR;
			break;

			default:
			return -EINVAL;
			}

			ep93xxfb_writel(fbi, val, EP93XXFB_PIXELMODE);
			return 0;
			}

			static void ep93xxfb_set_timing(struct fb_info *info)
			{
			struct ep93xx_fbi *fbi = info->par;
			unsigned int vlines_total, hclks_total, start, stop;

			vlines_total = info->var.yres + info->var.upper_margin +
			info->var.lower_margin + info->var.vsync_len - 1;

			hclks_total = info->var.xres + info->var.left_margin +
			info->var.right_margin + info->var.hsync_len - 1;

			ep93xxfb_out_locked(fbi, vlines_total, EP93XXFB_VLINES_TOTAL);
			ep93xxfb_out_locked(fbi, hclks_total, EP93XXFB_HCLKS_TOTAL);

			start = vlines_total;
			stop = vlines_total - info->var.vsync_len;
			ep93xxfb_out_locked(fbi, start \| (stop << 16), EP93XXFB_VSYNC);

			start = vlines_total - info->var.vsync_len - info->var.upper_margin;
			stop = info->var.lower_margin - 1;
			ep93xxfb_out_locked(fbi, start \| (stop << 16), EP93XXFB_VBLANK);
			ep93xxfb_out_locked(fbi, start \| (stop << 16), EP93XXFB_VACTIVE);

			start = vlines_total;
			stop = vlines_total + 1;
			ep93xxfb_out_locked(fbi, start \| (stop << 16), EP93XXFB_VCLK);

			start = hclks_total;
			stop = hclks_total - info->var.hsync_len;
			ep93xxfb_out_locked(fbi, start \| (stop << 16), EP93XXFB_HSYNC);

			start = hclks_total - info->var.hsync_len - info->var.left_margin;
			stop = info->var.right_margin - 1;
			ep93xxfb_out_locked(fbi, start \| (stop << 16), EP93XXFB_HBLANK);
			ep93xxfb_out_locked(fbi, start \| (stop << 16), EP93XXFB_HACTIVE);

			start = hclks_total;
			stop = hclks_total;
			ep93xxfb_out_locked(fbi, start \| (stop << 16), EP93XXFB_HCLK);

			ep93xxfb_out_locked(fbi, 0x0, EP93XXFB_LINE_CARRY);
			}

			static int ep93xxfb_set_par(struct fb_info *info)
			{
			struct ep93xx_fbi *fbi = info->par;

			clk_set_rate(fbi->clk, 1000 * PICOS2KHZ(info->var.pixclock));

			ep93xxfb_set_timing(info);

			info->fix.line_length = info->var.xres_virtual *
			info->var.bits_per_pixel / 8;

			ep93xxfb_writel(fbi, info->fix.smem_start, EP93XXFB_SCREEN_PAGE);
			ep93xxfb_writel(fbi, info->var.yres - 1, EP93XXFB_SCREEN_LINES);
			ep93xxfb_writel(fbi, ((info->var.xres * info->var.bits_per_pixel)
			/ 32) - 1, EP93XXFB_LINE_LENGTH);
			ep93xxfb_writel(fbi, info->fix.line_length / 4, EP93XXFB_VLINE_STEP);
			ep93xxfb_set_video_attribs(info);
			return 0;
			}

			static int ep93xxfb_check_var(struct fb_var_screeninfo *var,
			struct fb_info *info)
			{
			int err;

			err = ep93xxfb_set_pixelmode(info);
			if (err)
			return err;

			var->xres = max_t(unsigned int, var->xres, EP93XXFB_MIN_XRES);
			var->xres = min_t(unsigned int, var->xres, EP93XXFB_MAX_XRES);
			var->xres_virtual = max(var->xres_virtual, var->xres);

			var->yres = max_t(unsigned int, var->yres, EP93XXFB_MIN_YRES);
			var->yres = min_t(unsigned int, var->yres, EP93XXFB_MAX_YRES);
			var->yres_virtual = max(var->yres_virtual, var->yres);

			return 0;
			}

			static int ep93xxfb_mmap(struct fb_info info, struct vm_area_struct vma)
			{
			unsigned int offset = vma->vm_pgoff << PAGE_SHIFT;

			if (offset < info->fix.smem_len) {
			return dma_mmap_writecombine(info->dev, vma, info->screen_base,
			info->fix.smem_start,
			info->fix.smem_len);
			}

			return -EINVAL;
			}

			static int ep93xxfb_blank(int blank_mode, struct fb_info *info)
			{
			struct ep93xx_fbi *fbi = info->par;
			unsigned int attribs = ep93xxfb_readl(fbi, EP93XXFB_ATTRIBS);

			if (blank_mode) {
			if (fbi->mach_info->blank)
			fbi->mach_info->blank(blank_mode, info);
			ep93xxfb_out_locked(fbi, attribs & ~EP93XXFB_ENABLE,
			EP93XXFB_ATTRIBS);
			clk_disable(fbi->clk);
			} else {
			clk_enable(fbi->clk);
			ep93xxfb_out_locked(fbi, attribs \| EP93XXFB_ENABLE,
			EP93XXFB_ATTRIBS);
			if (fbi->mach_info->blank)
			fbi->mach_info->blank(blank_mode, info);
			}

			return 0;
			}

			static inline int ep93xxfb_convert_color(int val, int width)
			{
			return ((val << width) + 0x7fff - val) >> 16;
			}

			static int ep93xxfb_setcolreg(unsigned int regno, unsigned int red,
			unsigned int green, unsigned int blue,
			unsigned int transp, struct fb_info *info)
			{
			struct ep93xx_fbi *fbi = info->par;
			unsigned int *pal = info->pseudo_palette;
			unsigned int ctrl, i, rgb, lut_current, lut_stat;

			switch (info->fix.visual) {
			case FB_VISUAL_PSEUDOCOLOR:
			rgb = ((red & 0xff00) << 8) \| (green & 0xff00) \|
			((blue & 0xff00) >> 8);

			pal[regno] = rgb;
			ep93xxfb_writel(fbi, rgb, (EP93XXFB_COLOR_LUT + (regno << 2)));
			ctrl = ep93xxfb_readl(fbi, EP93XXFB_LUT_SW_CONTROL);
			lut_stat = !!(ctrl & EP93XXFB_LUT_SW_CONTROL_SSTAT);
			lut_current = !!(ctrl & EP93XXFB_LUT_SW_CONTROL_SWTCH);

			if (lut_stat == lut_current) {
			for (i = 0; i < 256; i++) {
			ep93xxfb_writel(fbi, pal[i],
			EP93XXFB_COLOR_LUT + (i << 2));
			}

			ep93xxfb_writel(fbi,
			ctrl ^ EP93XXFB_LUT_SW_CONTROL_SWTCH,
			EP93XXFB_LUT_SW_CONTROL);
			}
			break;

			case FB_VISUAL_TRUECOLOR:
			if (regno > 16)
			return 1;

			red = ep93xxfb_convert_color(red, info->var.red.length);
			green = ep93xxfb_convert_color(green, info->var.green.length);
			blue = ep93xxfb_convert_color(blue, info->var.blue.length);
			transp = ep93xxfb_convert_color(transp,
			info->var.transp.length);

			pal[regno] = (red << info->var.red.offset) \|
			(green << info->var.green.offset) \|
			(blue << info->var.blue.offset) \|
			(transp << info->var.transp.offset);
			break;

			default:
			return 1;
			}

			return 0;
			}

			static struct fb_ops ep93xxfb_ops = {
			.owner = THIS_MODULE,
			.fb_check_var = ep93xxfb_check_var,
			.fb_set_par = ep93xxfb_set_par,
			.fb_blank = ep93xxfb_blank,
			.fb_fillrect = cfb_fillrect,
			.fb_copyarea = cfb_copyarea,
			.fb_imageblit = cfb_imageblit,
			.fb_setcolreg = ep93xxfb_setcolreg,
			.fb_mmap = ep93xxfb_mmap,
			};

			static int __init ep93xxfb_calc_fbsize(struct ep93xxfb_mach_info *mach_info)
			{
			int i, fb_size = 0;

			if (mach_info->num_modes == EP93XXFB_USE_MODEDB) {
			fb_size = EP93XXFB_MAX_XRES * EP93XXFB_MAX_YRES *
			mach_info->bpp / 8;
			} else {
			for (i = 0; i < mach_info->num_modes; i++) {
			const struct fb_videomode *mode;
			int size;

			mode = &mach_info->modes[i];
			size = mode->xres * mode->yres * mach_info->bpp / 8;
			if (size > fb_size)
			fb_size = size;
			}
			}

			return fb_size;
			}

			static int __init ep93xxfb_alloc_videomem(struct fb_info *info)
			{
			struct ep93xx_fbi *fbi = info->par;
			char __iomem *virt_addr;
			dma_addr_t phys_addr;
			unsigned int fb_size;

			fb_size = ep93xxfb_calc_fbsize(fbi->mach_info);
			virt_addr = dma_alloc_writecombine(info->dev, fb_size,
			&phys_addr, GFP_KERNEL);
			if (!virt_addr)
			return -ENOMEM;

			/*
			* There is a bug in the ep93xx framebuffer which causes problems
			* if bit 27 of the physical address is set.
			* See: http://marc.info/?l=linux-arm-kernel&m=110061245502000&w=2
			* There does not seem to be any offical errata for this, but I
			* have confirmed the problem exists on my hardware (ep9315) at
			* least.
			*/
			if (check_screenpage_bug && phys_addr & (1 << 27)) {
			dev_err(info->dev, "ep93xx framebuffer bug. phys addr (0x%x) "
			"has bit 27 set: cannot init framebuffer\n",
			phys_addr);

			dma_free_coherent(info->dev, fb_size, virt_addr, phys_addr);
			return -ENOMEM;
			}

			info->fix.smem_start = phys_addr;
			info->fix.smem_len = fb_size;
			info->screen_base = virt_addr;

			return 0;
			}

			static void ep93xxfb_dealloc_videomem(struct fb_info *info)
			{
			if (info->screen_base)
			dma_free_coherent(info->dev, info->fix.smem_len,
			info->screen_base, info->fix.smem_start);
			}

			static int __init ep93xxfb_probe(struct platform_device *pdev)
			{
			struct ep93xxfb_mach_info *mach_info = pdev->dev.platform_data;
			struct fb_info *info;
			struct ep93xx_fbi *fbi;
			struct resource *res;
			char *video_mode;
			int err;

			if (!mach_info)
			return -EINVAL;

			info = framebuffer_alloc(sizeof(struct ep93xx_fbi), &pdev->dev);
			if (!info)
			return -ENOMEM;

			info->dev = &pdev->dev;
			platform_set_drvdata(pdev, info);
			fbi = info->par;
			fbi->mach_info = mach_info;

			err = fb_alloc_cmap(&info->cmap, 256, 0);
			if (err)
			goto failed;

			err = ep93xxfb_alloc_videomem(info);
			if (err)
			goto failed;

			res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
			if (!res) {
			err = -ENXIO;
			goto failed;
			}

			res = request_mem_region(res->start, resource_size(res), pdev->name);
			if (!res) {
			err = -EBUSY;
			goto failed;
			}

			fbi->res = res;
			fbi->mmio_base = ioremap(res->start, resource_size(res));
			if (!fbi->mmio_base) {
			err = -ENXIO;
			goto failed;
			}

			strcpy(info->fix.id, pdev->name);
			info->fbops = &ep93xxfb_ops;
			info->fix.type = FB_TYPE_PACKED_PIXELS;
			info->fix.accel = FB_ACCEL_NONE;
			info->var.activate = FB_ACTIVATE_NOW;
			info->var.vmode = FB_VMODE_NONINTERLACED;
			info->flags = FBINFO_DEFAULT;
			info->node = -1;
			info->state = FBINFO_STATE_RUNNING;
			info->pseudo_palette = &fbi->pseudo_palette;

			fb_get_options("ep93xx-fb", &video_mode);
			err = fb_find_mode(&info->var, info, video_mode,
			fbi->mach_info->modes, fbi->mach_info->num_modes,
			fbi->mach_info->default_mode, fbi->mach_info->bpp);
			if (err == 0) {
			dev_err(info->dev, "No suitable video mode found\n");
			err = -EINVAL;
			goto failed;
			}

			if (mach_info->setup) {
			err = mach_info->setup(pdev);
			if (err)
			return err;
			}

			err = ep93xxfb_check_var(&info->var, info);
			if (err)
			goto failed;

			fbi->clk = clk_get(info->dev, NULL);
			if (IS_ERR(fbi->clk)) {
			err = PTR_ERR(fbi->clk);
			fbi->clk = NULL;
			goto failed;
			}

			ep93xxfb_set_par(info);
			clk_enable(fbi->clk);

			err = register_framebuffer(info);
			if (err)
			goto failed;

			dev_info(info->dev, "registered. Mode = %dx%d-%d\n",
			info->var.xres, info->var.yres, info->var.bits_per_pixel);
			return 0;

			failed:
			if (fbi->clk)
			clk_put(fbi->clk);
			if (fbi->mmio_base)
			iounmap(fbi->mmio_base);
			if (fbi->res)
			release_mem_region(fbi->res->start, resource_size(fbi->res));
			ep93xxfb_dealloc_videomem(info);
			if (&info->cmap)
			fb_dealloc_cmap(&info->cmap);
			if (fbi->mach_info->teardown)
			fbi->mach_info->teardown(pdev);
			kfree(info);
			platform_set_drvdata(pdev, NULL);

			return err;
			}

			static int ep93xxfb_remove(struct platform_device *pdev)
			{
			struct fb_info *info = platform_get_drvdata(pdev);
			struct ep93xx_fbi *fbi = info->par;

			unregister_framebuffer(info);
			clk_disable(fbi->clk);
			clk_put(fbi->clk);
			iounmap(fbi->mmio_base);
			release_mem_region(fbi->res->start, resource_size(fbi->res));
			ep93xxfb_dealloc_videomem(info);
			fb_dealloc_cmap(&info->cmap);

			if (fbi->mach_info->teardown)
			fbi->mach_info->teardown(pdev);

			kfree(info);
			platform_set_drvdata(pdev, NULL);

			return 0;
			}

			static struct platform_driver ep93xxfb_driver = {
			.probe = ep93xxfb_probe,
			.remove = ep93xxfb_remove,
			.driver = {
			.name = "ep93xx-fb",
			.owner = THIS_MODULE,
			},
			};

			static int __devinit ep93xxfb_init(void)
			{
			return platform_driver_register(&ep93xxfb_driver);
			}

			static void __exit ep93xxfb_exit(void)
			{
			platform_driver_unregister(&ep93xxfb_driver);
			}

			module_init(ep93xxfb_init);
			module_exit(ep93xxfb_exit);

			MODULE_DESCRIPTION("EP93XX Framebuffer Driver");
			MODULE_ALIAS("platform:ep93xx-fb");
			MODULE_AUTHOR("Ryan Mallon <ryan&bluewatersys.com>, "
			"H Hartley Sweeten <hsweeten@visionengravers.com");
			MODULE_LICENSE("GPL");