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Date: Wed, 30 Sep 2020 16:38:47 +0200
From: Daniel Vetter <daniel@ffwll.ch>
To: Peter Collingbourne <pcc@google.com>
Subject: Re: [PATCH v2] Partially revert "video: fbdev: amba-clcd: Retire
 elder CLCD driver"
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Cc: Neil Armstrong <narmstrong@baylibre.com>,
 Linus Walleij <linus.walleij@linaro.org>,
 Kevin Brodsky <Kevin.Brodsky@arm.com>,
 Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
 Russell King <linux@armlinux.org.uk>,
 ML dri-devel <dri-devel@lists.freedesktop.org>, Eric Anholt <eric@anholt.net>,
 John Stultz <john.stultz@linaro.org>, Maxime Ripard <mripard@kernel.org>,
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On Tue, Sep 29, 2020 at 12:53:44PM -0700, Peter Collingbourne wrote:
> Also partially revert the follow-up change "drm: pl111: Absorb the
> external register header".
> 
> This reverts the parts of commits
> 7e4e589db76a3cf4c1f534eb5a09cc6422766b93 and
> 0fb8125635e8eb5483fb095f98dcf0651206a7b8 that touch paths outside
> of drivers/gpu/drm/pl111.
> 
> The fbdev driver is used by Android's FVP configuration. Using the
> DRM driver together with DRM's fbdev emulation results in a failure
> to boot Android. The root cause is that Android's generic fbdev
> userspace driver relies on the ability to set the pixel format via
> FBIOPUT_VSCREENINFO, which is not supported by fbdev emulation.
> 
> There have been other less critical behavioral differences identified
> between the fbdev driver and the DRM driver with fbdev emulation. The
> DRM driver exposes different values for the panel's width, height and
> refresh rate, and the DRM driver fails a FBIOPUT_VSCREENINFO syscall
> with yres_virtual greater than the maximum supported value instead
> of letting the syscall succeed and setting yres_virtual based on yres.
> 
> Signed-off-by: Peter Collingbourne <pcc@google.com>

Applied to drm-misc-fixes, should make it into Linus tree this week.
-Daniel

> ---
> View this change in Gerrit: https://linux-review.googlesource.com/q/I2d7e59b0e693d9fec206d40df190c5aa02844b56
> 
>  MAINTAINERS                     |   5 +
>  drivers/video/fbdev/Kconfig     |  20 +
>  drivers/video/fbdev/Makefile    |   1 +
>  drivers/video/fbdev/amba-clcd.c | 986 ++++++++++++++++++++++++++++++++
>  include/linux/amba/clcd-regs.h  |  87 +++
>  include/linux/amba/clcd.h       | 290 ++++++++++
>  6 files changed, 1389 insertions(+)
>  create mode 100644 drivers/video/fbdev/amba-clcd.c
>  create mode 100644 include/linux/amba/clcd-regs.h
>  create mode 100644 include/linux/amba/clcd.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 190c7fa2ea01..671c1fa79e64 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1460,6 +1460,11 @@ S:	Odd Fixes
>  F:	drivers/amba/
>  F:	include/linux/amba/bus.h
>  
> +ARM PRIMECELL CLCD PL110 DRIVER
> +M:	Russell King <linux@armlinux.org.uk>
> +S:	Odd Fixes
> +F:	drivers/video/fbdev/amba-clcd.*
> +
>  ARM PRIMECELL KMI PL050 DRIVER
>  M:	Russell King <linux@armlinux.org.uk>
>  S:	Odd Fixes
> diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig
> index b2c9dd4f0cb5..402e85450bb5 100644
> --- a/drivers/video/fbdev/Kconfig
> +++ b/drivers/video/fbdev/Kconfig
> @@ -272,6 +272,26 @@ config FB_PM2_FIFO_DISCONNECT
>  	help
>  	  Support the Permedia2 FIFO disconnect feature.
>  
> +config FB_ARMCLCD
> +	tristate "ARM PrimeCell PL110 support"
> +	depends on ARM || ARM64 || COMPILE_TEST
> +	depends on FB && ARM_AMBA && HAS_IOMEM
> +	select FB_CFB_FILLRECT
> +	select FB_CFB_COPYAREA
> +	select FB_CFB_IMAGEBLIT
> +	select FB_MODE_HELPERS if OF
> +	select VIDEOMODE_HELPERS if OF
> +	select BACKLIGHT_CLASS_DEVICE if OF
> +	help
> +	  This framebuffer device driver is for the ARM PrimeCell PL110
> +	  Colour LCD controller.  ARM PrimeCells provide the building
> +	  blocks for System on a Chip devices.
> +
> +	  If you want to compile this as a module (=code which can be
> +	  inserted into and removed from the running kernel), say M
> +	  here and read <file:Documentation/kbuild/modules.rst>.  The module
> +	  will be called amba-clcd.
> +
>  config FB_ACORN
>  	bool "Acorn VIDC support"
>  	depends on (FB = y) && ARM && ARCH_ACORN
> diff --git a/drivers/video/fbdev/Makefile b/drivers/video/fbdev/Makefile
> index cad4fb64442a..a0705b99e643 100644
> --- a/drivers/video/fbdev/Makefile
> +++ b/drivers/video/fbdev/Makefile
> @@ -75,6 +75,7 @@ obj-$(CONFIG_FB_HIT)              += hitfb.o
>  obj-$(CONFIG_FB_ATMEL)		  += atmel_lcdfb.o
>  obj-$(CONFIG_FB_PVR2)             += pvr2fb.o
>  obj-$(CONFIG_FB_VOODOO1)          += sstfb.o
> +obj-$(CONFIG_FB_ARMCLCD)	  += amba-clcd.o
>  obj-$(CONFIG_FB_GOLDFISH)         += goldfishfb.o
>  obj-$(CONFIG_FB_68328)            += 68328fb.o
>  obj-$(CONFIG_FB_GBE)              += gbefb.o
> diff --git a/drivers/video/fbdev/amba-clcd.c b/drivers/video/fbdev/amba-clcd.c
> new file mode 100644
> index 000000000000..b7682de412d8
> --- /dev/null
> +++ b/drivers/video/fbdev/amba-clcd.c
> @@ -0,0 +1,986 @@
> +/*
> + *  linux/drivers/video/amba-clcd.c
> + *
> + * Copyright (C) 2001 ARM Limited, by David A Rusling
> + * Updated to 2.5, Deep Blue Solutions Ltd.
> + *
> + * 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.
> + *
> + *  ARM PrimeCell PL110 Color LCD Controller
> + */
> +#include <linux/amba/bus.h>
> +#include <linux/amba/clcd.h>
> +#include <linux/backlight.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/fb.h>
> +#include <linux/init.h>
> +#include <linux/ioport.h>
> +#include <linux/list.h>
> +#include <linux/mm.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_graph.h>
> +#include <linux/slab.h>
> +#include <linux/string.h>
> +#include <video/display_timing.h>
> +#include <video/of_display_timing.h>
> +#include <video/videomode.h>
> +
> +#define to_clcd(info)	container_of(info, struct clcd_fb, fb)
> +
> +/* This is limited to 16 characters when displayed by X startup */
> +static const char *clcd_name = "CLCD FB";
> +
> +/*
> + * Unfortunately, the enable/disable functions may be called either from
> + * process or IRQ context, and we _need_ to delay.  This is _not_ good.
> + */
> +static inline void clcdfb_sleep(unsigned int ms)
> +{
> +	if (in_atomic()) {
> +		mdelay(ms);
> +	} else {
> +		msleep(ms);
> +	}
> +}
> +
> +static inline void clcdfb_set_start(struct clcd_fb *fb)
> +{
> +	unsigned long ustart = fb->fb.fix.smem_start;
> +	unsigned long lstart;
> +
> +	ustart += fb->fb.var.yoffset * fb->fb.fix.line_length;
> +	lstart = ustart + fb->fb.var.yres * fb->fb.fix.line_length / 2;
> +
> +	writel(ustart, fb->regs + CLCD_UBAS);
> +	writel(lstart, fb->regs + CLCD_LBAS);
> +}
> +
> +static void clcdfb_disable(struct clcd_fb *fb)
> +{
> +	u32 val;
> +
> +	if (fb->board->disable)
> +		fb->board->disable(fb);
> +
> +	if (fb->panel->backlight) {
> +		fb->panel->backlight->props.power = FB_BLANK_POWERDOWN;
> +		backlight_update_status(fb->panel->backlight);
> +	}
> +
> +	val = readl(fb->regs + fb->off_cntl);
> +	if (val & CNTL_LCDPWR) {
> +		val &= ~CNTL_LCDPWR;
> +		writel(val, fb->regs + fb->off_cntl);
> +
> +		clcdfb_sleep(20);
> +	}
> +	if (val & CNTL_LCDEN) {
> +		val &= ~CNTL_LCDEN;
> +		writel(val, fb->regs + fb->off_cntl);
> +	}
> +
> +	/*
> +	 * Disable CLCD clock source.
> +	 */
> +	if (fb->clk_enabled) {
> +		fb->clk_enabled = false;
> +		clk_disable(fb->clk);
> +	}
> +}
> +
> +static void clcdfb_enable(struct clcd_fb *fb, u32 cntl)
> +{
> +	/*
> +	 * Enable the CLCD clock source.
> +	 */
> +	if (!fb->clk_enabled) {
> +		fb->clk_enabled = true;
> +		clk_enable(fb->clk);
> +	}
> +
> +	/*
> +	 * Bring up by first enabling..
> +	 */
> +	cntl |= CNTL_LCDEN;
> +	writel(cntl, fb->regs + fb->off_cntl);
> +
> +	clcdfb_sleep(20);
> +
> +	/*
> +	 * and now apply power.
> +	 */
> +	cntl |= CNTL_LCDPWR;
> +	writel(cntl, fb->regs + fb->off_cntl);
> +
> +	/*
> +	 * Turn on backlight
> +	 */
> +	if (fb->panel->backlight) {
> +		fb->panel->backlight->props.power = FB_BLANK_UNBLANK;
> +		backlight_update_status(fb->panel->backlight);
> +	}
> +
> +	/*
> +	 * finally, enable the interface.
> +	 */
> +	if (fb->board->enable)
> +		fb->board->enable(fb);
> +}
> +
> +static int
> +clcdfb_set_bitfields(struct clcd_fb *fb, struct fb_var_screeninfo *var)
> +{
> +	u32 caps;
> +	int ret = 0;
> +
> +	if (fb->panel->caps && fb->board->caps)
> +		caps = fb->panel->caps & fb->board->caps;
> +	else {
> +		/* Old way of specifying what can be used */
> +		caps = fb->panel->cntl & CNTL_BGR ?
> +			CLCD_CAP_BGR : CLCD_CAP_RGB;
> +		/* But mask out 444 modes as they weren't supported */
> +		caps &= ~CLCD_CAP_444;
> +	}
> +
> +	/* Only TFT panels can do RGB888/BGR888 */
> +	if (!(fb->panel->cntl & CNTL_LCDTFT))
> +		caps &= ~CLCD_CAP_888;
> +
> +	memset(&var->transp, 0, sizeof(var->transp));
> +
> +	var->red.msb_right = 0;
> +	var->green.msb_right = 0;
> +	var->blue.msb_right = 0;
> +
> +	switch (var->bits_per_pixel) {
> +	case 1:
> +	case 2:
> +	case 4:
> +	case 8:
> +		/* If we can't do 5551, reject */
> +		caps &= CLCD_CAP_5551;
> +		if (!caps) {
> +			ret = -EINVAL;
> +			break;
> +		}
> +
> +		var->red.length		= var->bits_per_pixel;
> +		var->red.offset		= 0;
> +		var->green.length	= var->bits_per_pixel;
> +		var->green.offset	= 0;
> +		var->blue.length	= var->bits_per_pixel;
> +		var->blue.offset	= 0;
> +		break;
> +
> +	case 16:
> +		/* If we can't do 444, 5551 or 565, reject */
> +		if (!(caps & (CLCD_CAP_444 | CLCD_CAP_5551 | CLCD_CAP_565))) {
> +			ret = -EINVAL;
> +			break;
> +		}
> +
> +		/*
> +		 * Green length can be 4, 5 or 6 depending whether
> +		 * we're operating in 444, 5551 or 565 mode.
> +		 */
> +		if (var->green.length == 4 && caps & CLCD_CAP_444)
> +			caps &= CLCD_CAP_444;
> +		if (var->green.length == 5 && caps & CLCD_CAP_5551)
> +			caps &= CLCD_CAP_5551;
> +		else if (var->green.length == 6 && caps & CLCD_CAP_565)
> +			caps &= CLCD_CAP_565;
> +		else {
> +			/*
> +			 * PL110 officially only supports RGB555,
> +			 * but may be wired up to allow RGB565.
> +			 */
> +			if (caps & CLCD_CAP_565) {
> +				var->green.length = 6;
> +				caps &= CLCD_CAP_565;
> +			} else if (caps & CLCD_CAP_5551) {
> +				var->green.length = 5;
> +				caps &= CLCD_CAP_5551;
> +			} else {
> +				var->green.length = 4;
> +				caps &= CLCD_CAP_444;
> +			}
> +		}
> +
> +		if (var->green.length >= 5) {
> +			var->red.length = 5;
> +			var->blue.length = 5;
> +		} else {
> +			var->red.length = 4;
> +			var->blue.length = 4;
> +		}
> +		break;
> +	case 32:
> +		/* If we can't do 888, reject */
> +		caps &= CLCD_CAP_888;
> +		if (!caps) {
> +			ret = -EINVAL;
> +			break;
> +		}
> +
> +		var->red.length = 8;
> +		var->green.length = 8;
> +		var->blue.length = 8;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	/*
> +	 * >= 16bpp displays have separate colour component bitfields
> +	 * encoded in the pixel data.  Calculate their position from
> +	 * the bitfield length defined above.
> +	 */
> +	if (ret == 0 && var->bits_per_pixel >= 16) {
> +		bool bgr, rgb;
> +
> +		bgr = caps & CLCD_CAP_BGR && var->blue.offset == 0;
> +		rgb = caps & CLCD_CAP_RGB && var->red.offset == 0;
> +
> +		if (!bgr && !rgb)
> +			/*
> +			 * The requested format was not possible, try just
> +			 * our capabilities.  One of BGR or RGB must be
> +			 * supported.
> +			 */
> +			bgr = caps & CLCD_CAP_BGR;
> +
> +		if (bgr) {
> +			var->blue.offset = 0;
> +			var->green.offset = var->blue.offset + var->blue.length;
> +			var->red.offset = var->green.offset + var->green.length;
> +		} else {
> +			var->red.offset = 0;
> +			var->green.offset = var->red.offset + var->red.length;
> +			var->blue.offset = var->green.offset + var->green.length;
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static int clcdfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
> +{
> +	struct clcd_fb *fb = to_clcd(info);
> +	int ret = -EINVAL;
> +
> +	if (fb->board->check)
> +		ret = fb->board->check(fb, var);
> +
> +	if (ret == 0 &&
> +	    var->xres_virtual * var->bits_per_pixel / 8 *
> +	    var->yres_virtual > fb->fb.fix.smem_len)
> +		ret = -EINVAL;
> +
> +	if (ret == 0)
> +		ret = clcdfb_set_bitfields(fb, var);
> +
> +	return ret;
> +}
> +
> +static int clcdfb_set_par(struct fb_info *info)
> +{
> +	struct clcd_fb *fb = to_clcd(info);
> +	struct clcd_regs regs;
> +
> +	fb->fb.fix.line_length = fb->fb.var.xres_virtual *
> +				 fb->fb.var.bits_per_pixel / 8;
> +
> +	if (fb->fb.var.bits_per_pixel <= 8)
> +		fb->fb.fix.visual = FB_VISUAL_PSEUDOCOLOR;
> +	else
> +		fb->fb.fix.visual = FB_VISUAL_TRUECOLOR;
> +
> +	fb->board->decode(fb, &regs);
> +
> +	clcdfb_disable(fb);
> +
> +	writel(regs.tim0, fb->regs + CLCD_TIM0);
> +	writel(regs.tim1, fb->regs + CLCD_TIM1);
> +	writel(regs.tim2, fb->regs + CLCD_TIM2);
> +	writel(regs.tim3, fb->regs + CLCD_TIM3);
> +
> +	clcdfb_set_start(fb);
> +
> +	clk_set_rate(fb->clk, (1000000000 / regs.pixclock) * 1000);
> +
> +	fb->clcd_cntl = regs.cntl;
> +
> +	clcdfb_enable(fb, regs.cntl);
> +
> +#ifdef DEBUG
> +	printk(KERN_INFO
> +	       "CLCD: Registers set to\n"
> +	       "  %08x %08x %08x %08x\n"
> +	       "  %08x %08x %08x %08x\n",
> +		readl(fb->regs + CLCD_TIM0), readl(fb->regs + CLCD_TIM1),
> +		readl(fb->regs + CLCD_TIM2), readl(fb->regs + CLCD_TIM3),
> +		readl(fb->regs + CLCD_UBAS), readl(fb->regs + CLCD_LBAS),
> +		readl(fb->regs + fb->off_ienb), readl(fb->regs + fb->off_cntl));
> +#endif
> +
> +	return 0;
> +}
> +
> +static inline u32 convert_bitfield(int val, struct fb_bitfield *bf)
> +{
> +	unsigned int mask = (1 << bf->length) - 1;
> +
> +	return (val >> (16 - bf->length) & mask) << bf->offset;
> +}
> +
> +/*
> + *  Set a single color register. The values supplied have a 16 bit
> + *  magnitude.  Return != 0 for invalid regno.
> + */
> +static int
> +clcdfb_setcolreg(unsigned int regno, unsigned int red, unsigned int green,
> +		 unsigned int blue, unsigned int transp, struct fb_info *info)
> +{
> +	struct clcd_fb *fb = to_clcd(info);
> +
> +	if (regno < 16)
> +		fb->cmap[regno] = convert_bitfield(transp, &fb->fb.var.transp) |
> +				  convert_bitfield(blue, &fb->fb.var.blue) |
> +				  convert_bitfield(green, &fb->fb.var.green) |
> +				  convert_bitfield(red, &fb->fb.var.red);
> +
> +	if (fb->fb.fix.visual == FB_VISUAL_PSEUDOCOLOR && regno < 256) {
> +		int hw_reg = CLCD_PALETTE + ((regno * 2) & ~3);
> +		u32 val, mask, newval;
> +
> +		newval  = (red >> 11)  & 0x001f;
> +		newval |= (green >> 6) & 0x03e0;
> +		newval |= (blue >> 1)  & 0x7c00;
> +
> +		/*
> +		 * 3.2.11: if we're configured for big endian
> +		 * byte order, the palette entries are swapped.
> +		 */
> +		if (fb->clcd_cntl & CNTL_BEBO)
> +			regno ^= 1;
> +
> +		if (regno & 1) {
> +			newval <<= 16;
> +			mask = 0x0000ffff;
> +		} else {
> +			mask = 0xffff0000;
> +		}
> +
> +		val = readl(fb->regs + hw_reg) & mask;
> +		writel(val | newval, fb->regs + hw_reg);
> +	}
> +
> +	return regno > 255;
> +}
> +
> +/*
> + *  Blank the screen if blank_mode != 0, else unblank. If blank == NULL
> + *  then the caller blanks by setting the CLUT (Color Look Up Table) to all
> + *  black. Return 0 if blanking succeeded, != 0 if un-/blanking failed due
> + *  to e.g. a video mode which doesn't support it. Implements VESA suspend
> + *  and powerdown modes on hardware that supports disabling hsync/vsync:
> + *    blank_mode == 2: suspend vsync
> + *    blank_mode == 3: suspend hsync
> + *    blank_mode == 4: powerdown
> + */
> +static int clcdfb_blank(int blank_mode, struct fb_info *info)
> +{
> +	struct clcd_fb *fb = to_clcd(info);
> +
> +	if (blank_mode != 0) {
> +		clcdfb_disable(fb);
> +	} else {
> +		clcdfb_enable(fb, fb->clcd_cntl);
> +	}
> +	return 0;
> +}
> +
> +static int clcdfb_mmap(struct fb_info *info,
> +		       struct vm_area_struct *vma)
> +{
> +	struct clcd_fb *fb = to_clcd(info);
> +	unsigned long len, off = vma->vm_pgoff << PAGE_SHIFT;
> +	int ret = -EINVAL;
> +
> +	len = info->fix.smem_len;
> +
> +	if (off <= len && vma->vm_end - vma->vm_start <= len - off &&
> +	    fb->board->mmap)
> +		ret = fb->board->mmap(fb, vma);
> +
> +	return ret;
> +}
> +
> +static const struct fb_ops clcdfb_ops = {
> +	.owner		= THIS_MODULE,
> +	.fb_check_var	= clcdfb_check_var,
> +	.fb_set_par	= clcdfb_set_par,
> +	.fb_setcolreg	= clcdfb_setcolreg,
> +	.fb_blank	= clcdfb_blank,
> +	.fb_fillrect	= cfb_fillrect,
> +	.fb_copyarea	= cfb_copyarea,
> +	.fb_imageblit	= cfb_imageblit,
> +	.fb_mmap	= clcdfb_mmap,
> +};
> +
> +static int clcdfb_register(struct clcd_fb *fb)
> +{
> +	int ret;
> +
> +	/*
> +	 * ARM PL111 always has IENB at 0x1c; it's only PL110
> +	 * which is reversed on some platforms.
> +	 */
> +	if (amba_manf(fb->dev) == 0x41 && amba_part(fb->dev) == 0x111) {
> +		fb->off_ienb = CLCD_PL111_IENB;
> +		fb->off_cntl = CLCD_PL111_CNTL;
> +	} else {
> +		fb->off_ienb = CLCD_PL110_IENB;
> +		fb->off_cntl = CLCD_PL110_CNTL;
> +	}
> +
> +	fb->clk = clk_get(&fb->dev->dev, NULL);
> +	if (IS_ERR(fb->clk)) {
> +		ret = PTR_ERR(fb->clk);
> +		goto out;
> +	}
> +
> +	ret = clk_prepare(fb->clk);
> +	if (ret)
> +		goto free_clk;
> +
> +	fb->fb.device		= &fb->dev->dev;
> +
> +	fb->fb.fix.mmio_start	= fb->dev->res.start;
> +	fb->fb.fix.mmio_len	= resource_size(&fb->dev->res);
> +
> +	fb->regs = ioremap(fb->fb.fix.mmio_start, fb->fb.fix.mmio_len);
> +	if (!fb->regs) {
> +		printk(KERN_ERR "CLCD: unable to remap registers\n");
> +		ret = -ENOMEM;
> +		goto clk_unprep;
> +	}
> +
> +	fb->fb.fbops		= &clcdfb_ops;
> +	fb->fb.flags		= FBINFO_FLAG_DEFAULT;
> +	fb->fb.pseudo_palette	= fb->cmap;
> +
> +	strncpy(fb->fb.fix.id, clcd_name, sizeof(fb->fb.fix.id));
> +	fb->fb.fix.type		= FB_TYPE_PACKED_PIXELS;
> +	fb->fb.fix.type_aux	= 0;
> +	fb->fb.fix.xpanstep	= 0;
> +	fb->fb.fix.ypanstep	= 0;
> +	fb->fb.fix.ywrapstep	= 0;
> +	fb->fb.fix.accel	= FB_ACCEL_NONE;
> +
> +	fb->fb.var.xres		= fb->panel->mode.xres;
> +	fb->fb.var.yres		= fb->panel->mode.yres;
> +	fb->fb.var.xres_virtual	= fb->panel->mode.xres;
> +	fb->fb.var.yres_virtual	= fb->panel->mode.yres;
> +	fb->fb.var.bits_per_pixel = fb->panel->bpp;
> +	fb->fb.var.grayscale	= fb->panel->grayscale;
> +	fb->fb.var.pixclock	= fb->panel->mode.pixclock;
> +	fb->fb.var.left_margin	= fb->panel->mode.left_margin;
> +	fb->fb.var.right_margin	= fb->panel->mode.right_margin;
> +	fb->fb.var.upper_margin	= fb->panel->mode.upper_margin;
> +	fb->fb.var.lower_margin	= fb->panel->mode.lower_margin;
> +	fb->fb.var.hsync_len	= fb->panel->mode.hsync_len;
> +	fb->fb.var.vsync_len	= fb->panel->mode.vsync_len;
> +	fb->fb.var.sync		= fb->panel->mode.sync;
> +	fb->fb.var.vmode	= fb->panel->mode.vmode;
> +	fb->fb.var.activate	= FB_ACTIVATE_NOW;
> +	fb->fb.var.nonstd	= 0;
> +	fb->fb.var.height	= fb->panel->height;
> +	fb->fb.var.width	= fb->panel->width;
> +	fb->fb.var.accel_flags	= 0;
> +
> +	fb->fb.monspecs.hfmin	= 0;
> +	fb->fb.monspecs.hfmax   = 100000;
> +	fb->fb.monspecs.vfmin	= 0;
> +	fb->fb.monspecs.vfmax	= 400;
> +	fb->fb.monspecs.dclkmin = 1000000;
> +	fb->fb.monspecs.dclkmax	= 100000000;
> +
> +	/*
> +	 * Make sure that the bitfields are set appropriately.
> +	 */
> +	clcdfb_set_bitfields(fb, &fb->fb.var);
> +
> +	/*
> +	 * Allocate colourmap.
> +	 */
> +	ret = fb_alloc_cmap(&fb->fb.cmap, 256, 0);
> +	if (ret)
> +		goto unmap;
> +
> +	/*
> +	 * Ensure interrupts are disabled.
> +	 */
> +	writel(0, fb->regs + fb->off_ienb);
> +
> +	fb_set_var(&fb->fb, &fb->fb.var);
> +
> +	dev_info(&fb->dev->dev, "%s hardware, %s display\n",
> +	         fb->board->name, fb->panel->mode.name);
> +
> +	ret = register_framebuffer(&fb->fb);
> +	if (ret == 0)
> +		goto out;
> +
> +	printk(KERN_ERR "CLCD: cannot register framebuffer (%d)\n", ret);
> +
> +	fb_dealloc_cmap(&fb->fb.cmap);
> + unmap:
> +	iounmap(fb->regs);
> + clk_unprep:
> +	clk_unprepare(fb->clk);
> + free_clk:
> +	clk_put(fb->clk);
> + out:
> +	return ret;
> +}
> +
> +#ifdef CONFIG_OF
> +static int clcdfb_of_get_dpi_panel_mode(struct device_node *node,
> +		struct clcd_panel *clcd_panel)
> +{
> +	int err;
> +	struct display_timing timing;
> +	struct videomode video;
> +
> +	err = of_get_display_timing(node, "panel-timing", &timing);
> +	if (err) {
> +		pr_err("%pOF: problems parsing panel-timing (%d)\n", node, err);
> +		return err;
> +	}
> +
> +	videomode_from_timing(&timing, &video);
> +
> +	err = fb_videomode_from_videomode(&video, &clcd_panel->mode);
> +	if (err)
> +		return err;
> +
> +	/* Set up some inversion flags */
> +	if (timing.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE)
> +		clcd_panel->tim2 |= TIM2_IPC;
> +	else if (!(timing.flags & DISPLAY_FLAGS_PIXDATA_POSEDGE))
> +		/*
> +		 * To preserve backwards compatibility, the IPC (inverted
> +		 * pixel clock) flag needs to be set on any display that
> +		 * doesn't explicitly specify that the pixel clock is
> +		 * active on the negative or positive edge.
> +		 */
> +		clcd_panel->tim2 |= TIM2_IPC;
> +
> +	if (timing.flags & DISPLAY_FLAGS_HSYNC_LOW)
> +		clcd_panel->tim2 |= TIM2_IHS;
> +
> +	if (timing.flags & DISPLAY_FLAGS_VSYNC_LOW)
> +		clcd_panel->tim2 |= TIM2_IVS;
> +
> +	if (timing.flags & DISPLAY_FLAGS_DE_LOW)
> +		clcd_panel->tim2 |= TIM2_IOE;
> +
> +	return 0;
> +}
> +
> +static int clcdfb_snprintf_mode(char *buf, int size, struct fb_videomode *mode)
> +{
> +	return snprintf(buf, size, "%ux%u@%u", mode->xres, mode->yres,
> +			mode->refresh);
> +}
> +
> +static int clcdfb_of_get_backlight(struct device *dev,
> +				   struct clcd_panel *clcd_panel)
> +{
> +	struct backlight_device *backlight;
> +
> +	/* Look up the optional backlight device */
> +	backlight = devm_of_find_backlight(dev);
> +	if (IS_ERR(backlight))
> +		return PTR_ERR(backlight);
> +
> +	clcd_panel->backlight = backlight;
> +	return 0;
> +}
> +
> +static int clcdfb_of_get_mode(struct device *dev, struct device_node *panel,
> +			      struct clcd_panel *clcd_panel)
> +{
> +	int err;
> +	struct fb_videomode *mode;
> +	char *name;
> +	int len;
> +
> +	/* Only directly connected DPI panels supported for now */
> +	if (of_device_is_compatible(panel, "panel-dpi"))
> +		err = clcdfb_of_get_dpi_panel_mode(panel, clcd_panel);
> +	else
> +		err = -ENOENT;
> +	if (err)
> +		return err;
> +	mode = &clcd_panel->mode;
> +
> +	len = clcdfb_snprintf_mode(NULL, 0, mode);
> +	name = devm_kzalloc(dev, len + 1, GFP_KERNEL);
> +	if (!name)
> +		return -ENOMEM;
> +
> +	clcdfb_snprintf_mode(name, len + 1, mode);
> +	mode->name = name;
> +
> +	return 0;
> +}
> +
> +static int clcdfb_of_init_tft_panel(struct clcd_fb *fb, u32 r0, u32 g0, u32 b0)
> +{
> +	static struct {
> +		unsigned int part;
> +		u32 r0, g0, b0;
> +		u32 caps;
> +	} panels[] = {
> +		{ 0x110, 1,  7, 13, CLCD_CAP_5551 },
> +		{ 0x110, 0,  8, 16, CLCD_CAP_888 },
> +		{ 0x110, 16, 8, 0,  CLCD_CAP_888 },
> +		{ 0x111, 4, 14, 20, CLCD_CAP_444 },
> +		{ 0x111, 3, 11, 19, CLCD_CAP_444 | CLCD_CAP_5551 },
> +		{ 0x111, 3, 10, 19, CLCD_CAP_444 | CLCD_CAP_5551 |
> +				    CLCD_CAP_565 },
> +		{ 0x111, 0,  8, 16, CLCD_CAP_444 | CLCD_CAP_5551 |
> +				    CLCD_CAP_565 | CLCD_CAP_888 },
> +	};
> +	int i;
> +
> +	/* Bypass pixel clock divider */
> +	fb->panel->tim2 |= TIM2_BCD;
> +
> +	/* TFT display, vert. comp. interrupt at the start of the back porch */
> +	fb->panel->cntl |= CNTL_LCDTFT | CNTL_LCDVCOMP(1);
> +
> +	fb->panel->caps = 0;
> +
> +	/* Match the setup with known variants */
> +	for (i = 0; i < ARRAY_SIZE(panels) && !fb->panel->caps; i++) {
> +		if (amba_part(fb->dev) != panels[i].part)
> +			continue;
> +		if (g0 != panels[i].g0)
> +			continue;
> +		if (r0 == panels[i].r0 && b0 == panels[i].b0)
> +			fb->panel->caps = panels[i].caps;
> +	}
> +
> +	/*
> +	 * If we actually physically connected the R lines to B and
> +	 * vice versa
> +	 */
> +	if (r0 != 0 && b0 == 0)
> +		fb->panel->bgr_connection = true;
> +
> +	return fb->panel->caps ? 0 : -EINVAL;
> +}
> +
> +static int clcdfb_of_init_display(struct clcd_fb *fb)
> +{
> +	struct device_node *endpoint, *panel;
> +	int err;
> +	unsigned int bpp;
> +	u32 max_bandwidth;
> +	u32 tft_r0b0g0[3];
> +
> +	fb->panel = devm_kzalloc(&fb->dev->dev, sizeof(*fb->panel), GFP_KERNEL);
> +	if (!fb->panel)
> +		return -ENOMEM;
> +
> +	/*
> +	 * Fetch the panel endpoint.
> +	 */
> +	endpoint = of_graph_get_next_endpoint(fb->dev->dev.of_node, NULL);
> +	if (!endpoint)
> +		return -ENODEV;
> +
> +	panel = of_graph_get_remote_port_parent(endpoint);
> +	if (!panel)
> +		return -ENODEV;
> +
> +	err = clcdfb_of_get_backlight(&fb->dev->dev, fb->panel);
> +	if (err)
> +		return err;
> +
> +	err = clcdfb_of_get_mode(&fb->dev->dev, panel, fb->panel);
> +	if (err)
> +		return err;
> +
> +	err = of_property_read_u32(fb->dev->dev.of_node, "max-memory-bandwidth",
> +			&max_bandwidth);
> +	if (!err) {
> +		/*
> +		 * max_bandwidth is in bytes per second and pixclock in
> +		 * pico-seconds, so the maximum allowed bits per pixel is
> +		 *   8 * max_bandwidth / (PICOS2KHZ(pixclock) * 1000)
> +		 * Rearrange this calculation to avoid overflow and then ensure
> +		 * result is a valid format.
> +		 */
> +		bpp = max_bandwidth / (1000 / 8)
> +			/ PICOS2KHZ(fb->panel->mode.pixclock);
> +		bpp = rounddown_pow_of_two(bpp);
> +		if (bpp > 32)
> +			bpp = 32;
> +	} else
> +		bpp = 32;
> +	fb->panel->bpp = bpp;
> +
> +#ifdef CONFIG_CPU_BIG_ENDIAN
> +	fb->panel->cntl |= CNTL_BEBO;
> +#endif
> +	fb->panel->width = -1;
> +	fb->panel->height = -1;
> +
> +	if (of_property_read_u32_array(endpoint,
> +			"arm,pl11x,tft-r0g0b0-pads",
> +			tft_r0b0g0, ARRAY_SIZE(tft_r0b0g0)) != 0)
> +		return -ENOENT;
> +
> +	return clcdfb_of_init_tft_panel(fb, tft_r0b0g0[0],
> +					tft_r0b0g0[1],  tft_r0b0g0[2]);
> +}
> +
> +static int clcdfb_of_vram_setup(struct clcd_fb *fb)
> +{
> +	int err;
> +	struct device_node *memory;
> +	u64 size;
> +
> +	err = clcdfb_of_init_display(fb);
> +	if (err)
> +		return err;
> +
> +	memory = of_parse_phandle(fb->dev->dev.of_node, "memory-region", 0);
> +	if (!memory)
> +		return -ENODEV;
> +
> +	fb->fb.screen_base = of_iomap(memory, 0);
> +	if (!fb->fb.screen_base)
> +		return -ENOMEM;
> +
> +	fb->fb.fix.smem_start = of_translate_address(memory,
> +			of_get_address(memory, 0, &size, NULL));
> +	fb->fb.fix.smem_len = size;
> +
> +	return 0;
> +}
> +
> +static int clcdfb_of_vram_mmap(struct clcd_fb *fb, struct vm_area_struct *vma)
> +{
> +	unsigned long off, user_size, kernel_size;
> +
> +
> +	off = vma->vm_pgoff << PAGE_SHIFT;
> +	user_size = vma->vm_end - vma->vm_start;
> +	kernel_size = fb->fb.fix.smem_len;
> +
> +	if (off >= kernel_size || user_size > (kernel_size - off))
> +		return -ENXIO;
> +
> +	return remap_pfn_range(vma, vma->vm_start,
> +			__phys_to_pfn(fb->fb.fix.smem_start) + vma->vm_pgoff,
> +			user_size,
> +			pgprot_writecombine(vma->vm_page_prot));
> +}
> +
> +static void clcdfb_of_vram_remove(struct clcd_fb *fb)
> +{
> +	iounmap(fb->fb.screen_base);
> +}
> +
> +static int clcdfb_of_dma_setup(struct clcd_fb *fb)
> +{
> +	unsigned long framesize;
> +	dma_addr_t dma;
> +	int err;
> +
> +	err = clcdfb_of_init_display(fb);
> +	if (err)
> +		return err;
> +
> +	framesize = PAGE_ALIGN(fb->panel->mode.xres * fb->panel->mode.yres *
> +			fb->panel->bpp / 8);
> +	fb->fb.screen_base = dma_alloc_coherent(&fb->dev->dev, framesize,
> +			&dma, GFP_KERNEL);
> +	if (!fb->fb.screen_base)
> +		return -ENOMEM;
> +
> +	fb->fb.fix.smem_start = dma;
> +	fb->fb.fix.smem_len = framesize;
> +
> +	return 0;
> +}
> +
> +static int clcdfb_of_dma_mmap(struct clcd_fb *fb, struct vm_area_struct *vma)
> +{
> +	return dma_mmap_wc(&fb->dev->dev, vma, fb->fb.screen_base,
> +			   fb->fb.fix.smem_start, fb->fb.fix.smem_len);
> +}
> +
> +static void clcdfb_of_dma_remove(struct clcd_fb *fb)
> +{
> +	dma_free_coherent(&fb->dev->dev, fb->fb.fix.smem_len,
> +			fb->fb.screen_base, fb->fb.fix.smem_start);
> +}
> +
> +static struct clcd_board *clcdfb_of_get_board(struct amba_device *dev)
> +{
> +	struct clcd_board *board = devm_kzalloc(&dev->dev, sizeof(*board),
> +			GFP_KERNEL);
> +	struct device_node *node = dev->dev.of_node;
> +
> +	if (!board)
> +		return NULL;
> +
> +	board->name = of_node_full_name(node);
> +	board->caps = CLCD_CAP_ALL;
> +	board->check = clcdfb_check;
> +	board->decode = clcdfb_decode;
> +	if (of_find_property(node, "memory-region", NULL)) {
> +		board->setup = clcdfb_of_vram_setup;
> +		board->mmap = clcdfb_of_vram_mmap;
> +		board->remove = clcdfb_of_vram_remove;
> +	} else {
> +		board->setup = clcdfb_of_dma_setup;
> +		board->mmap = clcdfb_of_dma_mmap;
> +		board->remove = clcdfb_of_dma_remove;
> +	}
> +
> +	return board;
> +}
> +#else
> +static struct clcd_board *clcdfb_of_get_board(struct amba_device *dev)
> +{
> +	return NULL;
> +}
> +#endif
> +
> +static int clcdfb_probe(struct amba_device *dev, const struct amba_id *id)
> +{
> +	struct clcd_board *board = dev_get_platdata(&dev->dev);
> +	struct clcd_fb *fb;
> +	int ret;
> +
> +	if (!board)
> +		board = clcdfb_of_get_board(dev);
> +
> +	if (!board)
> +		return -EINVAL;
> +
> +	ret = dma_set_mask_and_coherent(&dev->dev, DMA_BIT_MASK(32));
> +	if (ret)
> +		goto out;
> +
> +	ret = amba_request_regions(dev, NULL);
> +	if (ret) {
> +		printk(KERN_ERR "CLCD: unable to reserve regs region\n");
> +		goto out;
> +	}
> +
> +	fb = kzalloc(sizeof(*fb), GFP_KERNEL);
> +	if (!fb) {
> +		ret = -ENOMEM;
> +		goto free_region;
> +	}
> +
> +	fb->dev = dev;
> +	fb->board = board;
> +
> +	dev_info(&fb->dev->dev, "PL%03x designer %02x rev%u at 0x%08llx\n",
> +		amba_part(dev), amba_manf(dev), amba_rev(dev),
> +		(unsigned long long)dev->res.start);
> +
> +	ret = fb->board->setup(fb);
> +	if (ret)
> +		goto free_fb;
> +
> +	ret = clcdfb_register(fb);
> +	if (ret == 0) {
> +		amba_set_drvdata(dev, fb);
> +		goto out;
> +	}
> +
> +	fb->board->remove(fb);
> + free_fb:
> +	kfree(fb);
> + free_region:
> +	amba_release_regions(dev);
> + out:
> +	return ret;
> +}
> +
> +static int clcdfb_remove(struct amba_device *dev)
> +{
> +	struct clcd_fb *fb = amba_get_drvdata(dev);
> +
> +	clcdfb_disable(fb);
> +	unregister_framebuffer(&fb->fb);
> +	if (fb->fb.cmap.len)
> +		fb_dealloc_cmap(&fb->fb.cmap);
> +	iounmap(fb->regs);
> +	clk_unprepare(fb->clk);
> +	clk_put(fb->clk);
> +
> +	fb->board->remove(fb);
> +
> +	kfree(fb);
> +
> +	amba_release_regions(dev);
> +
> +	return 0;
> +}
> +
> +static const struct amba_id clcdfb_id_table[] = {
> +	{
> +		.id	= 0x00041110,
> +		.mask	= 0x000ffffe,
> +	},
> +	{ 0, 0 },
> +};
> +
> +MODULE_DEVICE_TABLE(amba, clcdfb_id_table);
> +
> +static struct amba_driver clcd_driver = {
> +	.drv 		= {
> +		.name	= "clcd-pl11x",
> +	},
> +	.probe		= clcdfb_probe,
> +	.remove		= clcdfb_remove,
> +	.id_table	= clcdfb_id_table,
> +};
> +
> +static int __init amba_clcdfb_init(void)
> +{
> +	if (fb_get_options("ambafb", NULL))
> +		return -ENODEV;
> +
> +	return amba_driver_register(&clcd_driver);
> +}
> +
> +module_init(amba_clcdfb_init);
> +
> +static void __exit amba_clcdfb_exit(void)
> +{
> +	amba_driver_unregister(&clcd_driver);
> +}
> +
> +module_exit(amba_clcdfb_exit);
> +
> +MODULE_DESCRIPTION("ARM PrimeCell PL110 CLCD core driver");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/amba/clcd-regs.h b/include/linux/amba/clcd-regs.h
> new file mode 100644
> index 000000000000..421b0fa90d6a
> --- /dev/null
> +++ b/include/linux/amba/clcd-regs.h
> @@ -0,0 +1,87 @@
> +/*
> + * David A Rusling
> + *
> + * Copyright (C) 2001 ARM Limited
> + *
> + * 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.
> + */
> +
> +#ifndef AMBA_CLCD_REGS_H
> +#define AMBA_CLCD_REGS_H
> +
> +/*
> + * CLCD Controller Internal Register addresses
> + */
> +#define CLCD_TIM0		0x00000000
> +#define CLCD_TIM1 		0x00000004
> +#define CLCD_TIM2 		0x00000008
> +#define CLCD_TIM3 		0x0000000c
> +#define CLCD_UBAS 		0x00000010
> +#define CLCD_LBAS 		0x00000014
> +
> +#define CLCD_PL110_IENB		0x00000018
> +#define CLCD_PL110_CNTL		0x0000001c
> +#define CLCD_PL110_STAT		0x00000020
> +#define CLCD_PL110_INTR 	0x00000024
> +#define CLCD_PL110_UCUR		0x00000028
> +#define CLCD_PL110_LCUR		0x0000002C
> +
> +#define CLCD_PL111_CNTL		0x00000018
> +#define CLCD_PL111_IENB		0x0000001c
> +#define CLCD_PL111_RIS		0x00000020
> +#define CLCD_PL111_MIS		0x00000024
> +#define CLCD_PL111_ICR		0x00000028
> +#define CLCD_PL111_UCUR		0x0000002c
> +#define CLCD_PL111_LCUR		0x00000030
> +
> +#define CLCD_PALL 		0x00000200
> +#define CLCD_PALETTE		0x00000200
> +
> +#define TIM2_PCD_LO_MASK	GENMASK(4, 0)
> +#define TIM2_PCD_LO_BITS	5
> +#define TIM2_CLKSEL		(1 << 5)
> +#define TIM2_ACB_MASK		GENMASK(10, 6)
> +#define TIM2_IVS		(1 << 11)
> +#define TIM2_IHS		(1 << 12)
> +#define TIM2_IPC		(1 << 13)
> +#define TIM2_IOE		(1 << 14)
> +#define TIM2_BCD		(1 << 26)
> +#define TIM2_PCD_HI_MASK	GENMASK(31, 27)
> +#define TIM2_PCD_HI_BITS	5
> +#define TIM2_PCD_HI_SHIFT	27
> +
> +#define CNTL_LCDEN		(1 << 0)
> +#define CNTL_LCDBPP1		(0 << 1)
> +#define CNTL_LCDBPP2		(1 << 1)
> +#define CNTL_LCDBPP4		(2 << 1)
> +#define CNTL_LCDBPP8		(3 << 1)
> +#define CNTL_LCDBPP16		(4 << 1)
> +#define CNTL_LCDBPP16_565	(6 << 1)
> +#define CNTL_LCDBPP16_444	(7 << 1)
> +#define CNTL_LCDBPP24		(5 << 1)
> +#define CNTL_LCDBW		(1 << 4)
> +#define CNTL_LCDTFT		(1 << 5)
> +#define CNTL_LCDMONO8		(1 << 6)
> +#define CNTL_LCDDUAL		(1 << 7)
> +#define CNTL_BGR		(1 << 8)
> +#define CNTL_BEBO		(1 << 9)
> +#define CNTL_BEPO		(1 << 10)
> +#define CNTL_LCDPWR		(1 << 11)
> +#define CNTL_LCDVCOMP(x)	((x) << 12)
> +#define CNTL_LDMAFIFOTIME	(1 << 15)
> +#define CNTL_WATERMARK		(1 << 16)
> +
> +/* ST Microelectronics variant bits */
> +#define CNTL_ST_1XBPP_444	0x0
> +#define CNTL_ST_1XBPP_5551	(1 << 17)
> +#define CNTL_ST_1XBPP_565	(1 << 18)
> +#define CNTL_ST_CDWID_12	0x0
> +#define CNTL_ST_CDWID_16	(1 << 19)
> +#define CNTL_ST_CDWID_18	(1 << 20)
> +#define CNTL_ST_CDWID_24	((1 << 19)|(1 << 20))
> +#define CNTL_ST_CEAEN		(1 << 21)
> +#define CNTL_ST_LCDBPP24_PACKED	(6 << 1)
> +
> +#endif /* AMBA_CLCD_REGS_H */
> diff --git a/include/linux/amba/clcd.h b/include/linux/amba/clcd.h
> new file mode 100644
> index 000000000000..b6e0cbeaf533
> --- /dev/null
> +++ b/include/linux/amba/clcd.h
> @@ -0,0 +1,290 @@
> +/*
> + * linux/include/asm-arm/hardware/amba_clcd.h -- Integrator LCD panel.
> + *
> + * David A Rusling
> + *
> + * Copyright (C) 2001 ARM Limited
> + *
> + * 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.
> + */
> +#include <linux/fb.h>
> +#include <linux/amba/clcd-regs.h>
> +
> +enum {
> +	/* individual formats */
> +	CLCD_CAP_RGB444		= (1 << 0),
> +	CLCD_CAP_RGB5551	= (1 << 1),
> +	CLCD_CAP_RGB565		= (1 << 2),
> +	CLCD_CAP_RGB888		= (1 << 3),
> +	CLCD_CAP_BGR444		= (1 << 4),
> +	CLCD_CAP_BGR5551	= (1 << 5),
> +	CLCD_CAP_BGR565		= (1 << 6),
> +	CLCD_CAP_BGR888		= (1 << 7),
> +
> +	/* connection layouts */
> +	CLCD_CAP_444		= CLCD_CAP_RGB444 | CLCD_CAP_BGR444,
> +	CLCD_CAP_5551		= CLCD_CAP_RGB5551 | CLCD_CAP_BGR5551,
> +	CLCD_CAP_565		= CLCD_CAP_RGB565 | CLCD_CAP_BGR565,
> +	CLCD_CAP_888		= CLCD_CAP_RGB888 | CLCD_CAP_BGR888,
> +
> +	/* red/blue ordering */
> +	CLCD_CAP_RGB		= CLCD_CAP_RGB444 | CLCD_CAP_RGB5551 |
> +				  CLCD_CAP_RGB565 | CLCD_CAP_RGB888,
> +	CLCD_CAP_BGR		= CLCD_CAP_BGR444 | CLCD_CAP_BGR5551 |
> +				  CLCD_CAP_BGR565 | CLCD_CAP_BGR888,
> +
> +	CLCD_CAP_ALL		= CLCD_CAP_BGR | CLCD_CAP_RGB,
> +};
> +
> +struct backlight_device;
> +
> +struct clcd_panel {
> +	struct fb_videomode	mode;
> +	signed short		width;	/* width in mm */
> +	signed short		height;	/* height in mm */
> +	u32			tim2;
> +	u32			tim3;
> +	u32			cntl;
> +	u32			caps;
> +	unsigned int		bpp:8,
> +				fixedtimings:1,
> +				grayscale:1;
> +	unsigned int		connector;
> +	struct backlight_device	*backlight;
> +	/*
> +	 * If the B/R lines are switched between the CLCD
> +	 * and the panel we need to know this and not try to
> +	 * compensate with the BGR bit in the control register.
> +	 */
> +	bool			bgr_connection;
> +};
> +
> +struct clcd_regs {
> +	u32			tim0;
> +	u32			tim1;
> +	u32			tim2;
> +	u32			tim3;
> +	u32			cntl;
> +	unsigned long		pixclock;
> +};
> +
> +struct clcd_fb;
> +
> +/*
> + * the board-type specific routines
> + */
> +struct clcd_board {
> +	const char *name;
> +
> +	/*
> +	 * Optional.  Hardware capability flags.
> +	 */
> +	u32	caps;
> +
> +	/*
> +	 * Optional.  Check whether the var structure is acceptable
> +	 * for this display.
> +	 */
> +	int	(*check)(struct clcd_fb *fb, struct fb_var_screeninfo *var);
> +
> +	/*
> +	 * Compulsory.  Decode fb->fb.var into regs->*.  In the case of
> +	 * fixed timing, set regs->* to the register values required.
> +	 */
> +	void	(*decode)(struct clcd_fb *fb, struct clcd_regs *regs);
> +
> +	/*
> +	 * Optional.  Disable any extra display hardware.
> +	 */
> +	void	(*disable)(struct clcd_fb *);
> +
> +	/*
> +	 * Optional.  Enable any extra display hardware.
> +	 */
> +	void	(*enable)(struct clcd_fb *);
> +
> +	/*
> +	 * Setup platform specific parts of CLCD driver
> +	 */
> +	int	(*setup)(struct clcd_fb *);
> +
> +	/*
> +	 * mmap the framebuffer memory
> +	 */
> +	int	(*mmap)(struct clcd_fb *, struct vm_area_struct *);
> +
> +	/*
> +	 * Remove platform specific parts of CLCD driver
> +	 */
> +	void	(*remove)(struct clcd_fb *);
> +};
> +
> +struct amba_device;
> +struct clk;
> +
> +/* this data structure describes each frame buffer device we find */
> +struct clcd_fb {
> +	struct fb_info		fb;
> +	struct amba_device	*dev;
> +	struct clk		*clk;
> +	struct clcd_panel	*panel;
> +	struct clcd_board	*board;
> +	void			*board_data;
> +	void __iomem		*regs;
> +	u16			off_ienb;
> +	u16			off_cntl;
> +	u32			clcd_cntl;
> +	u32			cmap[16];
> +	bool			clk_enabled;
> +};
> +
> +static inline void clcdfb_decode(struct clcd_fb *fb, struct clcd_regs *regs)
> +{
> +	struct fb_var_screeninfo *var = &fb->fb.var;
> +	u32 val, cpl;
> +
> +	/*
> +	 * Program the CLCD controller registers and start the CLCD
> +	 */
> +	val = ((var->xres / 16) - 1) << 2;
> +	val |= (var->hsync_len - 1) << 8;
> +	val |= (var->right_margin - 1) << 16;
> +	val |= (var->left_margin - 1) << 24;
> +	regs->tim0 = val;
> +
> +	val = var->yres;
> +	if (fb->panel->cntl & CNTL_LCDDUAL)
> +		val /= 2;
> +	val -= 1;
> +	val |= (var->vsync_len - 1) << 10;
> +	val |= var->lower_margin << 16;
> +	val |= var->upper_margin << 24;
> +	regs->tim1 = val;
> +
> +	val = fb->panel->tim2;
> +	val |= var->sync & FB_SYNC_HOR_HIGH_ACT  ? 0 : TIM2_IHS;
> +	val |= var->sync & FB_SYNC_VERT_HIGH_ACT ? 0 : TIM2_IVS;
> +
> +	cpl = var->xres_virtual;
> +	if (fb->panel->cntl & CNTL_LCDTFT)	  /* TFT */
> +		/* / 1 */;
> +	else if (!var->grayscale)		  /* STN color */
> +		cpl = cpl * 8 / 3;
> +	else if (fb->panel->cntl & CNTL_LCDMONO8) /* STN monochrome, 8bit */
> +		cpl /= 8;
> +	else					  /* STN monochrome, 4bit */
> +		cpl /= 4;
> +
> +	regs->tim2 = val | ((cpl - 1) << 16);
> +
> +	regs->tim3 = fb->panel->tim3;
> +
> +	val = fb->panel->cntl;
> +	if (var->grayscale)
> +		val |= CNTL_LCDBW;
> +
> +	if (fb->panel->caps && fb->board->caps && var->bits_per_pixel >= 16) {
> +		/*
> +		 * if board and panel supply capabilities, we can support
> +		 * changing BGR/RGB depending on supplied parameters. Here
> +		 * we switch to what the framebuffer is providing if need
> +		 * be, so if the framebuffer is BGR but the display connection
> +		 * is RGB (first case) we switch it around. Vice versa mutatis
> +		 * mutandis if the framebuffer is RGB but the display connection
> +		 * is BGR, we flip it around.
> +		 */
> +		if (var->red.offset == 0)
> +			val &= ~CNTL_BGR;
> +		else
> +			val |= CNTL_BGR;
> +		if (fb->panel->bgr_connection)
> +			val ^= CNTL_BGR;
> +	}
> +
> +	switch (var->bits_per_pixel) {
> +	case 1:
> +		val |= CNTL_LCDBPP1;
> +		break;
> +	case 2:
> +		val |= CNTL_LCDBPP2;
> +		break;
> +	case 4:
> +		val |= CNTL_LCDBPP4;
> +		break;
> +	case 8:
> +		val |= CNTL_LCDBPP8;
> +		break;
> +	case 16:
> +		/*
> +		 * PL110 cannot choose between 5551 and 565 modes in its
> +		 * control register.  It is possible to use 565 with
> +		 * custom external wiring.
> +		 */
> +		if (amba_part(fb->dev) == 0x110 ||
> +		    var->green.length == 5)
> +			val |= CNTL_LCDBPP16;
> +		else if (var->green.length == 6)
> +			val |= CNTL_LCDBPP16_565;
> +		else
> +			val |= CNTL_LCDBPP16_444;
> +		break;
> +	case 32:
> +		val |= CNTL_LCDBPP24;
> +		break;
> +	}
> +
> +	regs->cntl = val;
> +	regs->pixclock = var->pixclock;
> +}
> +
> +static inline int clcdfb_check(struct clcd_fb *fb, struct fb_var_screeninfo *var)
> +{
> +	var->xres_virtual = var->xres = (var->xres + 15) & ~15;
> +	var->yres_virtual = var->yres = (var->yres + 1) & ~1;
> +
> +#define CHECK(e,l,h) (var->e < l || var->e > h)
> +	if (CHECK(right_margin, (5+1), 256) ||	/* back porch */
> +	    CHECK(left_margin, (5+1), 256) ||	/* front porch */
> +	    CHECK(hsync_len, (5+1), 256) ||
> +	    var->xres > 4096 ||
> +	    var->lower_margin > 255 ||		/* back porch */
> +	    var->upper_margin > 255 ||		/* front porch */
> +	    var->vsync_len > 32 ||
> +	    var->yres > 1024)
> +		return -EINVAL;
> +#undef CHECK
> +
> +	/* single panel mode: PCD = max(PCD, 1) */
> +	/* dual panel mode: PCD = max(PCD, 5) */
> +
> +	/*
> +	 * You can't change the grayscale setting, and
> +	 * we can only do non-interlaced video.
> +	 */
> +	if (var->grayscale != fb->fb.var.grayscale ||
> +	    (var->vmode & FB_VMODE_MASK) != FB_VMODE_NONINTERLACED)
> +		return -EINVAL;
> +
> +#define CHECK(e) (var->e != fb->fb.var.e)
> +	if (fb->panel->fixedtimings &&
> +	    (CHECK(xres)		||
> +	     CHECK(yres)		||
> +	     CHECK(bits_per_pixel)	||
> +	     CHECK(pixclock)		||
> +	     CHECK(left_margin)		||
> +	     CHECK(right_margin)	||
> +	     CHECK(upper_margin)	||
> +	     CHECK(lower_margin)	||
> +	     CHECK(hsync_len)		||
> +	     CHECK(vsync_len)		||
> +	     CHECK(sync)))
> +		return -EINVAL;
> +#undef CHECK
> +
> +	var->nonstd = 0;
> +	var->accel_flags = 0;
> +
> +	return 0;
> +}
> -- 
> 2.28.0.709.gb0816b6eb0-goog
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

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