VisionFive2 Linux kernel

StarFive Tech Linux Kernel for VisionFive (JH7110) boards (mirror)

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author: Peter Collingbourne <pcc@google.com> 2020-09-29 12:53:44 -0700 committer: Daniel Vetter <daniel.vetter@ffwll.ch> 2020-09-30 16:37:39 +0200 commit: 112c35237c726cb2c6eed32db660f285938fb666 parent: 5af08640795b2b9a940c9266c0260455377ae262
Commit Summary:
Partially revert "video: fbdev: amba-clcd: Retire elder CLCD driver"
Diffstat:
3 files changed, 835 insertions, 0 deletions
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");