From bb3b2cfeb206f5b10b859e134651b54120e3f530 Mon Sep 17 00:00:00 2001
From: Linus Walleij <linusw@kernel.org>
Date: Tue, 30 Jun 2026 18:05:56 +0100
Subject: ARM: 9480/1: entry: expand comment in __switch_to

As per discussion between the developers in the mail thread
linked, expand the comment in __switch_to so that readers
of the code understand what is going on.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 drivers/video/fbdev/imxfb.c | 1110 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 1110 insertions(+)
 create mode 100644 drivers/video/fbdev/imxfb.c

(limited to 'drivers/video/fbdev/imxfb.c')

diff --git a/drivers/video/fbdev/imxfb.c b/drivers/video/fbdev/imxfb.c
new file mode 100644
index 000000000..a077bf346
--- /dev/null
+++ b/drivers/video/fbdev/imxfb.c
@@ -0,0 +1,1110 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Freescale i.MX Frame Buffer device driver
+ *
+ *  Copyright (C) 2004 Sascha Hauer, Pengutronix
+ *   Based on acornfb.c Copyright (C) Russell King.
+ *
+ * Please direct your questions and comments on this driver to the following
+ * email address:
+ *
+ *	linux-arm-kernel@lists.arm.linux.org.uk
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/fb.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/cpufreq.h>
+#include <linux/clk.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/io.h>
+#include <linux/lcd.h>
+#include <linux/math64.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/bitfield.h>
+
+#include <linux/regulator/consumer.h>
+
+#include <video/of_display_timing.h>
+#include <video/of_videomode.h>
+#include <video/videomode.h>
+
+struct imx_fb_videomode {
+	struct fb_videomode mode;
+	u32 pcr;
+	bool aus_mode;
+	unsigned char	bpp;
+};
+
+/*
+ * Complain if VAR is out of range.
+ */
+#define DEBUG_VAR 1
+
+#define DRIVER_NAME "imx-fb"
+
+#define LCDC_SSA	0x00
+
+#define LCDC_SIZE	0x04
+#define SIZE_XMAX_MASK	GENMASK(25, 20)
+
+#define YMAX_MASK_IMX1	GENMASK(8, 0)
+#define YMAX_MASK_IMX21	GENMASK(9, 0)
+
+#define LCDC_VPW	0x08
+#define VPW_VPW_MASK	GENMASK(9, 0)
+
+#define LCDC_CPOS	0x0C
+#define CPOS_CC1	BIT(31)
+#define CPOS_CC0	BIT(30)
+#define CPOS_OP		BIT(28)
+#define CPOS_CXP_MASK	GENMASK(25, 16)
+
+#define LCDC_LCWHB	0x10
+#define LCWHB_BK_EN	BIT(31)
+#define LCWHB_CW_MASK	GENMASK(28, 24)
+#define LCWHB_CH_MASK	GENMASK(20, 16)
+#define LCWHB_BD_MASK	GENMASK(7, 0)
+
+#define LCDC_LCHCC	0x14
+
+#define LCDC_PCR	0x18
+#define PCR_TFT		BIT(31)
+#define PCR_COLOR	BIT(30)
+#define PCR_BPIX_MASK	GENMASK(27, 25)
+#define PCR_BPIX_8	3
+#define PCR_BPIX_12	4
+#define PCR_BPIX_16	5
+#define PCR_BPIX_18	6
+#define PCR_PCD_MASK	GENMASK(5, 0)
+
+#define LCDC_HCR	0x1C
+#define HCR_H_WIDTH_MASK	GENMASK(31, 26)
+#define HCR_H_WAIT_1_MASK	GENMASK(15, 8)
+#define HCR_H_WAIT_2_MASK	GENMASK(7, 0)
+
+#define LCDC_VCR	0x20
+#define VCR_V_WIDTH_MASK	GENMASK(31, 26)
+#define VCR_V_WAIT_1_MASK	GENMASK(15, 8)
+#define VCR_V_WAIT_2_MASK	GENMASK(7, 0)
+
+#define LCDC_POS	0x24
+#define POS_POS_MASK	GENMASK(4, 0)
+
+#define LCDC_LSCR1	0x28
+/* bit fields in imxfb.h */
+
+#define LCDC_PWMR	0x2C
+/* bit fields in imxfb.h */
+
+#define LCDC_DMACR	0x30
+/* bit fields in imxfb.h */
+
+#define LCDC_RMCR	0x34
+
+#define RMCR_LCDC_EN_MX1	BIT(1)
+
+#define RMCR_SELF_REF	BIT(0)
+
+#define LCDC_LCDICR	0x38
+#define LCDICR_INT_SYN	BIT(2)
+#define LCDICR_INT_CON	BIT(0)
+
+#define LCDC_LCDISR	0x40
+#define LCDISR_UDR_ERR	BIT(3)
+#define LCDISR_ERR_RES	BIT(2)
+#define LCDISR_EOF	BIT(1)
+#define LCDISR_BOF	BIT(0)
+
+#define IMXFB_LSCR1_DEFAULT 0x00120300
+
+#define LCDC_LAUSCR	0x80
+#define LAUSCR_AUS_MODE	BIT(31)
+
+/* Used fb-mode. Can be set on kernel command line, therefore file-static. */
+static const char *fb_mode;
+
+/*
+ * These are the bitfields for each
+ * display depth that we support.
+ */
+struct imxfb_rgb {
+	struct fb_bitfield	red;
+	struct fb_bitfield	green;
+	struct fb_bitfield	blue;
+	struct fb_bitfield	transp;
+};
+
+enum imxfb_type {
+	IMX1_FB,
+	IMX21_FB,
+};
+
+enum imxfb_panel_type {
+	PANEL_TYPE_MONOCHROME,
+	PANEL_TYPE_CSTN,
+	PANEL_TYPE_TFT,
+};
+
+struct imxfb_info {
+	struct platform_device  *pdev;
+	void __iomem		*regs;
+	struct clk		*clk_ipg;
+	struct clk		*clk_ahb;
+	struct clk		*clk_per;
+	enum imxfb_type		devtype;
+	enum imxfb_panel_type	panel_type;
+	bool			enabled;
+
+	/*
+	 * These are the addresses we mapped
+	 * the framebuffer memory region to.
+	 */
+	dma_addr_t		map_dma;
+	u_int			map_size;
+
+	u_int			palette_size;
+
+	dma_addr_t		dbar1;
+	dma_addr_t		dbar2;
+
+	u_int			pcr;
+	u_int			lauscr;
+	u_int			pwmr;
+	u_int			lscr1;
+	u_int			dmacr;
+	bool			cmap_inverse;
+	bool			cmap_static;
+
+	struct imx_fb_videomode *mode;
+	int			num_modes;
+
+	struct regulator	*lcd_pwr;
+	int			lcd_pwr_enabled;
+};
+
+static const struct platform_device_id imxfb_devtype[] = {
+	{
+		.name = "imx1-fb",
+		.driver_data = IMX1_FB,
+	}, {
+		.name = "imx21-fb",
+		.driver_data = IMX21_FB,
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(platform, imxfb_devtype);
+
+static const struct of_device_id imxfb_of_dev_id[] = {
+	{
+		.compatible = "fsl,imx1-fb",
+		.data = &imxfb_devtype[IMX1_FB],
+	}, {
+		.compatible = "fsl,imx21-fb",
+		.data = &imxfb_devtype[IMX21_FB],
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(of, imxfb_of_dev_id);
+
+static inline int is_imx1_fb(struct imxfb_info *fbi)
+{
+	return fbi->devtype == IMX1_FB;
+}
+
+#define IMX_NAME	"IMX"
+
+/*
+ * Minimum X and Y resolutions
+ */
+#define MIN_XRES	64
+#define MIN_YRES	64
+
+/* Actually this really is 18bit support, the lowest 2 bits of each colour
+ * are unused in hardware. We claim to have 24bit support to make software
+ * like X work, which does not support 18bit.
+ */
+static struct imxfb_rgb def_rgb_18 = {
+	.red	= {.offset = 16, .length = 8,},
+	.green	= {.offset = 8, .length = 8,},
+	.blue	= {.offset = 0, .length = 8,},
+	.transp = {.offset = 0, .length = 0,},
+};
+
+static struct imxfb_rgb def_rgb_16_tft = {
+	.red	= {.offset = 11, .length = 5,},
+	.green	= {.offset = 5, .length = 6,},
+	.blue	= {.offset = 0, .length = 5,},
+	.transp = {.offset = 0, .length = 0,},
+};
+
+static struct imxfb_rgb def_rgb_16_stn = {
+	.red	= {.offset = 8, .length = 4,},
+	.green	= {.offset = 4, .length = 4,},
+	.blue	= {.offset = 0, .length = 4,},
+	.transp = {.offset = 0, .length = 0,},
+};
+
+static struct imxfb_rgb def_rgb_8 = {
+	.red	= {.offset = 0, .length = 8,},
+	.green	= {.offset = 0, .length = 8,},
+	.blue	= {.offset = 0, .length = 8,},
+	.transp = {.offset = 0, .length = 0,},
+};
+
+static int imxfb_activate_var(struct fb_var_screeninfo *var,
+		struct fb_info *info);
+
+static inline u_int chan_to_field(u_int chan, struct fb_bitfield *bf)
+{
+	chan &= 0xffff;
+	chan >>= 16 - bf->length;
+	return chan << bf->offset;
+}
+
+static int imxfb_setpalettereg(u_int regno, u_int red, u_int green, u_int blue,
+		u_int trans, struct fb_info *info)
+{
+	struct imxfb_info *fbi = info->par;
+	u_int val, ret = 1;
+
+#define CNVT_TOHW(val, width) ((((val)<<(width))+0x7FFF-(val))>>16)
+	if (regno < fbi->palette_size) {
+		val = (CNVT_TOHW(red, 4) << 8) |
+		      (CNVT_TOHW(green, 4) << 4) |
+		      CNVT_TOHW(blue,  4);
+
+		writel(val, fbi->regs + 0x800 + (regno << 2));
+		ret = 0;
+	}
+	return ret;
+}
+
+static int imxfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
+		   u_int trans, struct fb_info *info)
+{
+	struct imxfb_info *fbi = info->par;
+	unsigned int val;
+	int ret = 1;
+
+	/*
+	 * If inverse mode was selected, invert all the colours
+	 * rather than the register number.  The register number
+	 * is what you poke into the framebuffer to produce the
+	 * colour you requested.
+	 */
+	if (fbi->cmap_inverse) {
+		red   = 0xffff - red;
+		green = 0xffff - green;
+		blue  = 0xffff - blue;
+	}
+
+	/*
+	 * If greyscale is true, then we convert the RGB value
+	 * to greyscale no mater what visual we are using.
+	 */
+	if (info->var.grayscale)
+		red = green = blue = (19595 * red + 38470 * green +
+					7471 * blue) >> 16;
+
+	switch (info->fix.visual) {
+	case FB_VISUAL_TRUECOLOR:
+		/*
+		 * 12 or 16-bit True Colour.  We encode the RGB value
+		 * according to the RGB bitfield information.
+		 */
+		if (regno < 16) {
+			u32 *pal = info->pseudo_palette;
+
+			val  = chan_to_field(red, &info->var.red);
+			val |= chan_to_field(green, &info->var.green);
+			val |= chan_to_field(blue, &info->var.blue);
+
+			pal[regno] = val;
+			ret = 0;
+		}
+		break;
+
+	case FB_VISUAL_STATIC_PSEUDOCOLOR:
+	case FB_VISUAL_PSEUDOCOLOR:
+		ret = imxfb_setpalettereg(regno, red, green, blue, trans, info);
+		break;
+	}
+
+	return ret;
+}
+
+static const struct imx_fb_videomode *imxfb_find_mode(struct imxfb_info *fbi)
+{
+	struct imx_fb_videomode *m;
+	int i;
+
+	if (!fb_mode)
+		return &fbi->mode[0];
+
+	for (i = 0, m = &fbi->mode[0]; i < fbi->num_modes; i++, m++) {
+		if (!strcmp(m->mode.name, fb_mode))
+			return m;
+	}
+	return NULL;
+}
+
+/*
+ *  imxfb_check_var():
+ *    Round up in the following order: bits_per_pixel, xres,
+ *    yres, xres_virtual, yres_virtual, xoffset, yoffset, grayscale,
+ *    bitfields, horizontal timing, vertical timing.
+ */
+static int imxfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
+{
+	struct imxfb_info *fbi = info->par;
+	struct imxfb_rgb *rgb;
+	const struct imx_fb_videomode *imxfb_mode;
+	unsigned long lcd_clk;
+	unsigned long long tmp;
+	u32 pcr = 0;
+
+	if (var->xres < MIN_XRES)
+		var->xres = MIN_XRES;
+	if (var->yres < MIN_YRES)
+		var->yres = MIN_YRES;
+
+	imxfb_mode = imxfb_find_mode(fbi);
+	if (!imxfb_mode)
+		return -EINVAL;
+
+	var->xres		= imxfb_mode->mode.xres;
+	var->yres		= imxfb_mode->mode.yres;
+	var->bits_per_pixel	= imxfb_mode->bpp;
+	var->pixclock		= imxfb_mode->mode.pixclock;
+	var->hsync_len		= imxfb_mode->mode.hsync_len;
+	var->left_margin	= imxfb_mode->mode.left_margin;
+	var->right_margin	= imxfb_mode->mode.right_margin;
+	var->vsync_len		= imxfb_mode->mode.vsync_len;
+	var->upper_margin	= imxfb_mode->mode.upper_margin;
+	var->lower_margin	= imxfb_mode->mode.lower_margin;
+	var->sync		= imxfb_mode->mode.sync;
+	var->xres_virtual	= max(var->xres_virtual, var->xres);
+	var->yres_virtual	= max(var->yres_virtual, var->yres);
+
+	pr_debug("var->bits_per_pixel=%d\n", var->bits_per_pixel);
+
+	lcd_clk = clk_get_rate(fbi->clk_per);
+
+	tmp = var->pixclock * (unsigned long long)lcd_clk;
+
+	do_div(tmp, 1000000);
+
+	if (do_div(tmp, 1000000) > 500000)
+		tmp++;
+
+	pcr = (unsigned int)tmp;
+
+	if (--pcr > PCR_PCD_MASK) {
+		pcr = PCR_PCD_MASK;
+		dev_warn(&fbi->pdev->dev, "Must limit pixel clock to %luHz\n",
+			 lcd_clk / pcr);
+	}
+
+	switch (var->bits_per_pixel) {
+	case 32:
+		pcr |= FIELD_PREP(PCR_BPIX_MASK, PCR_BPIX_18);
+		rgb = &def_rgb_18;
+		break;
+	case 16:
+	default:
+		if (is_imx1_fb(fbi))
+			pcr |= FIELD_PREP(PCR_BPIX_MASK, PCR_BPIX_12);
+		else
+			pcr |= FIELD_PREP(PCR_BPIX_MASK, PCR_BPIX_16);
+
+		if (imxfb_mode->pcr & PCR_TFT)
+			rgb = &def_rgb_16_tft;
+		else
+			rgb = &def_rgb_16_stn;
+		break;
+	case 8:
+		pcr |= FIELD_PREP(PCR_BPIX_MASK, PCR_BPIX_8);
+		rgb = &def_rgb_8;
+		break;
+	}
+
+	/* add sync polarities */
+	pcr |= imxfb_mode->pcr & ~(PCR_PCD_MASK | PCR_BPIX_MASK);
+
+	fbi->pcr = pcr;
+	/*
+	 * The LCDC AUS Mode Control Register does not exist on imx1.
+	 */
+	if (!is_imx1_fb(fbi) && imxfb_mode->aus_mode)
+		fbi->lauscr = LAUSCR_AUS_MODE;
+
+	if (imxfb_mode->pcr & PCR_TFT)
+		fbi->panel_type = PANEL_TYPE_TFT;
+	else if (imxfb_mode->pcr & PCR_COLOR)
+		fbi->panel_type = PANEL_TYPE_CSTN;
+	else
+		fbi->panel_type = PANEL_TYPE_MONOCHROME;
+
+	/*
+	 * Copy the RGB parameters for this display
+	 * from the machine specific parameters.
+	 */
+	var->red    = rgb->red;
+	var->green  = rgb->green;
+	var->blue   = rgb->blue;
+	var->transp = rgb->transp;
+
+	pr_debug("RGBT length = %d:%d:%d:%d\n",
+		var->red.length, var->green.length, var->blue.length,
+		var->transp.length);
+
+	pr_debug("RGBT offset = %d:%d:%d:%d\n",
+		var->red.offset, var->green.offset, var->blue.offset,
+		var->transp.offset);
+
+	return 0;
+}
+
+/*
+ * imxfb_set_par():
+ *	Set the user defined part of the display for the specified console
+ */
+static int imxfb_set_par(struct fb_info *info)
+{
+	struct imxfb_info *fbi = info->par;
+	struct fb_var_screeninfo *var = &info->var;
+
+	if (var->bits_per_pixel == 16 || var->bits_per_pixel == 32)
+		info->fix.visual = FB_VISUAL_TRUECOLOR;
+	else if (!fbi->cmap_static)
+		info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
+	else {
+		/*
+		 * Some people have weird ideas about wanting static
+		 * pseudocolor maps.  I suspect their user space
+		 * applications are broken.
+		 */
+		info->fix.visual = FB_VISUAL_STATIC_PSEUDOCOLOR;
+	}
+
+	info->fix.line_length = var->xres_virtual * var->bits_per_pixel / 8;
+	fbi->palette_size = var->bits_per_pixel == 8 ? 256 : 16;
+
+	imxfb_activate_var(var, info);
+
+	return 0;
+}
+
+static int imxfb_enable_controller(struct imxfb_info *fbi)
+{
+	int ret;
+
+	if (fbi->enabled)
+		return 0;
+
+	pr_debug("Enabling LCD controller\n");
+
+	writel(fbi->map_dma, fbi->regs + LCDC_SSA);
+
+	/* panning offset 0 (0 pixel offset)        */
+	writel(FIELD_PREP(POS_POS_MASK, 0), fbi->regs + LCDC_POS);
+
+	/* disable hardware cursor */
+	writel(readl(fbi->regs + LCDC_CPOS) & ~(CPOS_CC0 | CPOS_CC1),
+		fbi->regs + LCDC_CPOS);
+
+	/*
+	 * RMCR_LCDC_EN_MX1 is present on i.MX1 only, but doesn't hurt
+	 * on other SoCs
+	 */
+	writel(RMCR_LCDC_EN_MX1, fbi->regs + LCDC_RMCR);
+
+	ret = clk_prepare_enable(fbi->clk_ipg);
+	if (ret)
+		goto err_enable_ipg;
+
+	ret = clk_prepare_enable(fbi->clk_ahb);
+	if (ret)
+		goto err_enable_ahb;
+
+	ret = clk_prepare_enable(fbi->clk_per);
+	if (ret)
+		goto err_enable_per;
+
+	fbi->enabled = true;
+	return 0;
+
+err_enable_per:
+	clk_disable_unprepare(fbi->clk_ahb);
+err_enable_ahb:
+	clk_disable_unprepare(fbi->clk_ipg);
+err_enable_ipg:
+	writel(0, fbi->regs + LCDC_RMCR);
+
+	return ret;
+}
+
+static void imxfb_disable_controller(struct imxfb_info *fbi)
+{
+	if (!fbi->enabled)
+		return;
+
+	pr_debug("Disabling LCD controller\n");
+
+	clk_disable_unprepare(fbi->clk_per);
+	clk_disable_unprepare(fbi->clk_ahb);
+	clk_disable_unprepare(fbi->clk_ipg);
+	fbi->enabled = false;
+
+	writel(0, fbi->regs + LCDC_RMCR);
+}
+
+static int imxfb_blank(int blank, struct fb_info *info)
+{
+	struct imxfb_info *fbi = info->par;
+
+	pr_debug("%s: blank=%d\n", __func__, blank);
+
+	switch (blank) {
+	case FB_BLANK_POWERDOWN:
+	case FB_BLANK_VSYNC_SUSPEND:
+	case FB_BLANK_HSYNC_SUSPEND:
+	case FB_BLANK_NORMAL:
+		imxfb_disable_controller(fbi);
+		break;
+
+	case FB_BLANK_UNBLANK:
+		return imxfb_enable_controller(fbi);
+	}
+	return 0;
+}
+
+static const struct fb_ops imxfb_ops = {
+	.owner		= THIS_MODULE,
+	FB_DEFAULT_IOMEM_OPS,
+	.fb_check_var	= imxfb_check_var,
+	.fb_set_par	= imxfb_set_par,
+	.fb_setcolreg	= imxfb_setcolreg,
+	.fb_blank	= imxfb_blank,
+};
+
+/*
+ * imxfb_activate_var():
+ *	Configures LCD Controller based on entries in var parameter.  Settings are
+ *	only written to the controller if changes were made.
+ */
+static int imxfb_activate_var(struct fb_var_screeninfo *var, struct fb_info *info)
+{
+	struct imxfb_info *fbi = info->par;
+	u32 ymax_mask = is_imx1_fb(fbi) ? YMAX_MASK_IMX1 : YMAX_MASK_IMX21;
+	u8 left_margin_low;
+
+	pr_debug("var: xres=%d hslen=%d lm=%d rm=%d\n",
+		var->xres, var->hsync_len,
+		var->left_margin, var->right_margin);
+	pr_debug("var: yres=%d vslen=%d um=%d bm=%d\n",
+		var->yres, var->vsync_len,
+		var->upper_margin, var->lower_margin);
+
+	if (fbi->panel_type == PANEL_TYPE_TFT)
+		left_margin_low = 3;
+	else if (fbi->panel_type == PANEL_TYPE_CSTN)
+		left_margin_low = 2;
+	else
+		left_margin_low = 0;
+
+#if DEBUG_VAR
+	if (var->xres < 16        || var->xres > 1024)
+		dev_err(&fbi->pdev->dev, "%s: invalid xres %d\n",
+			info->fix.id, var->xres);
+	if (var->hsync_len < 1    || var->hsync_len > 64)
+		dev_err(&fbi->pdev->dev, "%s: invalid hsync_len %d\n",
+			info->fix.id, var->hsync_len);
+	if (var->left_margin < left_margin_low  || var->left_margin > 255)
+		dev_err(&fbi->pdev->dev, "%s: invalid left_margin %d\n",
+			info->fix.id, var->left_margin);
+	if (var->right_margin < 1 || var->right_margin > 255)
+		dev_err(&fbi->pdev->dev, "%s: invalid right_margin %d\n",
+			info->fix.id, var->right_margin);
+	if (var->yres < 1 || var->yres > ymax_mask)
+		dev_err(&fbi->pdev->dev, "%s: invalid yres %d\n",
+			info->fix.id, var->yres);
+	if (var->vsync_len > 100)
+		dev_err(&fbi->pdev->dev, "%s: invalid vsync_len %d\n",
+			info->fix.id, var->vsync_len);
+	if (var->upper_margin > 63)
+		dev_err(&fbi->pdev->dev, "%s: invalid upper_margin %d\n",
+			info->fix.id, var->upper_margin);
+	if (var->lower_margin > 255)
+		dev_err(&fbi->pdev->dev, "%s: invalid lower_margin %d\n",
+			info->fix.id, var->lower_margin);
+#endif
+
+	/* physical screen start address	    */
+	writel(FIELD_PREP(VPW_VPW_MASK,
+			  var->xres * var->bits_per_pixel / 8 / 4),
+	       fbi->regs + LCDC_VPW);
+
+	writel(FIELD_PREP(HCR_H_WIDTH_MASK, var->hsync_len - 1) |
+	       FIELD_PREP(HCR_H_WAIT_1_MASK, var->right_margin - 1) |
+	       FIELD_PREP(HCR_H_WAIT_2_MASK,
+			  var->left_margin - left_margin_low),
+	       fbi->regs + LCDC_HCR);
+
+	writel(FIELD_PREP(VCR_V_WIDTH_MASK, var->vsync_len) |
+	       FIELD_PREP(VCR_V_WAIT_1_MASK, var->lower_margin) |
+	       FIELD_PREP(VCR_V_WAIT_2_MASK, var->upper_margin),
+	       fbi->regs + LCDC_VCR);
+
+	writel(FIELD_PREP(SIZE_XMAX_MASK, var->xres >> 4) |
+	       (var->yres & ymax_mask),
+	       fbi->regs + LCDC_SIZE);
+
+	writel(fbi->pcr, fbi->regs + LCDC_PCR);
+	if (fbi->pwmr)
+		writel(fbi->pwmr, fbi->regs + LCDC_PWMR);
+	writel(fbi->lscr1, fbi->regs + LCDC_LSCR1);
+
+	/* dmacr = 0 is no valid value, as we need DMA control marks. */
+	if (fbi->dmacr)
+		writel(fbi->dmacr, fbi->regs + LCDC_DMACR);
+
+	if (fbi->lauscr)
+		writel(fbi->lauscr, fbi->regs + LCDC_LAUSCR);
+
+	return 0;
+}
+
+static int imxfb_init_fbinfo(struct platform_device *pdev)
+{
+	struct fb_info *info = platform_get_drvdata(pdev);
+	struct imxfb_info *fbi = info->par;
+	struct device_node *np;
+
+	info->pseudo_palette = devm_kmalloc_array(&pdev->dev, 16,
+						  sizeof(u32), GFP_KERNEL);
+	if (!info->pseudo_palette)
+		return -ENOMEM;
+
+	memset(fbi, 0, sizeof(struct imxfb_info));
+
+	fbi->pdev = pdev;
+	fbi->devtype = pdev->id_entry->driver_data;
+
+	strscpy(info->fix.id, IMX_NAME, sizeof(info->fix.id));
+
+	info->fix.type			= FB_TYPE_PACKED_PIXELS;
+	info->fix.type_aux		= 0;
+	info->fix.xpanstep		= 0;
+	info->fix.ypanstep		= 0;
+	info->fix.ywrapstep		= 0;
+	info->fix.accel			= FB_ACCEL_NONE;
+
+	info->var.nonstd		= 0;
+	info->var.activate		= FB_ACTIVATE_NOW;
+	info->var.height		= -1;
+	info->var.width	= -1;
+	info->var.accel_flags		= 0;
+	info->var.vmode			= FB_VMODE_NONINTERLACED;
+
+	info->fbops			= &imxfb_ops;
+	info->flags			= FBINFO_READS_FAST;
+
+	np = pdev->dev.of_node;
+	info->var.grayscale = of_property_read_bool(np,
+					"cmap-greyscale");
+	fbi->cmap_inverse = of_property_read_bool(np, "cmap-inverse");
+	fbi->cmap_static = of_property_read_bool(np, "cmap-static");
+
+	fbi->lscr1 = IMXFB_LSCR1_DEFAULT;
+
+	of_property_read_u32(np, "fsl,lpccr", &fbi->pwmr);
+
+	of_property_read_u32(np, "fsl,lscr1", &fbi->lscr1);
+
+	of_property_read_u32(np, "fsl,dmacr", &fbi->dmacr);
+
+	return 0;
+}
+
+static int imxfb_of_read_mode(struct device *dev, struct device_node *np,
+		struct imx_fb_videomode *imxfb_mode)
+{
+	int ret;
+	struct fb_videomode *of_mode = &imxfb_mode->mode;
+	u32 bpp;
+	u32 pcr;
+
+	ret = of_property_read_string(np, "model", &of_mode->name);
+	if (ret)
+		of_mode->name = NULL;
+
+	ret = of_get_fb_videomode(np, of_mode, OF_USE_NATIVE_MODE);
+	if (ret) {
+		dev_err(dev, "Failed to get videomode from DT\n");
+		return ret;
+	}
+
+	ret = of_property_read_u32(np, "bits-per-pixel", &bpp);
+	ret |= of_property_read_u32(np, "fsl,pcr", &pcr);
+
+	if (ret) {
+		dev_err(dev, "Failed to read bpp and pcr from DT\n");
+		return -EINVAL;
+	}
+
+	if (bpp < 1 || bpp > 255) {
+		dev_err(dev, "Bits per pixel have to be between 1 and 255\n");
+		return -EINVAL;
+	}
+
+	imxfb_mode->bpp = bpp;
+	imxfb_mode->pcr = pcr;
+
+	/*
+	 * fsl,aus-mode is optional
+	 */
+	imxfb_mode->aus_mode = of_property_read_bool(np, "fsl,aus-mode");
+
+	return 0;
+}
+
+static int imxfb_lcd_get_contrast(struct lcd_device *lcddev)
+{
+	struct imxfb_info *fbi = dev_get_drvdata(&lcddev->dev);
+
+	return fbi->pwmr & 0xff;
+}
+
+static int imxfb_lcd_set_contrast(struct lcd_device *lcddev, int contrast)
+{
+	struct imxfb_info *fbi = dev_get_drvdata(&lcddev->dev);
+
+	if (fbi->pwmr && fbi->enabled) {
+		if (contrast > 255)
+			contrast = 255;
+		else if (contrast < 0)
+			contrast = 0;
+
+		fbi->pwmr &= ~0xff;
+		fbi->pwmr |= contrast;
+
+		writel(fbi->pwmr, fbi->regs + LCDC_PWMR);
+	}
+
+	return 0;
+}
+
+static int imxfb_lcd_get_power(struct lcd_device *lcddev)
+{
+	struct imxfb_info *fbi = dev_get_drvdata(&lcddev->dev);
+
+	if (!IS_ERR(fbi->lcd_pwr) &&
+	    !regulator_is_enabled(fbi->lcd_pwr))
+		return LCD_POWER_OFF;
+
+	return LCD_POWER_ON;
+}
+
+static int imxfb_regulator_set(struct imxfb_info *fbi, int enable)
+{
+	int ret;
+
+	if (enable == fbi->lcd_pwr_enabled)
+		return 0;
+
+	if (enable)
+		ret = regulator_enable(fbi->lcd_pwr);
+	else
+		ret = regulator_disable(fbi->lcd_pwr);
+
+	if (ret == 0)
+		fbi->lcd_pwr_enabled = enable;
+
+	return ret;
+}
+
+static int imxfb_lcd_set_power(struct lcd_device *lcddev, int power)
+{
+	struct imxfb_info *fbi = dev_get_drvdata(&lcddev->dev);
+
+	if (!IS_ERR(fbi->lcd_pwr))
+		return imxfb_regulator_set(fbi, power == LCD_POWER_ON);
+
+	return 0;
+}
+
+static const struct lcd_ops imxfb_lcd_ops = {
+	.get_contrast	= imxfb_lcd_get_contrast,
+	.set_contrast	= imxfb_lcd_set_contrast,
+	.get_power	= imxfb_lcd_get_power,
+	.set_power	= imxfb_lcd_set_power,
+};
+
+static int imxfb_setup(void)
+{
+	char *opt, *options = NULL;
+
+	if (fb_get_options("imxfb", &options))
+		return -ENODEV;
+
+	if (!options || !*options)
+		return 0;
+
+	while ((opt = strsep(&options, ",")) != NULL) {
+		if (!*opt)
+			continue;
+		else
+			fb_mode = opt;
+	}
+
+	return 0;
+}
+
+static int imxfb_probe(struct platform_device *pdev)
+{
+	struct imxfb_info *fbi;
+	struct lcd_device *lcd;
+	struct fb_info *info;
+	struct imx_fb_videomode *m;
+	const struct of_device_id *of_id;
+	struct device_node *display_np;
+	int ret, i;
+	int bytes_per_pixel;
+
+	dev_info(&pdev->dev, "i.MX Framebuffer driver\n");
+
+	ret = imxfb_setup();
+	if (ret < 0)
+		return ret;
+
+	of_id = of_match_device(imxfb_of_dev_id, &pdev->dev);
+	if (of_id)
+		pdev->id_entry = of_id->data;
+
+	info = framebuffer_alloc(sizeof(struct imxfb_info), &pdev->dev);
+	if (!info)
+		return -ENOMEM;
+
+	fbi = info->par;
+
+	platform_set_drvdata(pdev, info);
+
+	ret = imxfb_init_fbinfo(pdev);
+	if (ret < 0)
+		goto failed_init;
+
+	fb_mode = NULL;
+
+	display_np = of_parse_phandle(pdev->dev.of_node, "display", 0);
+	if (!display_np) {
+		dev_err(&pdev->dev, "No display defined in devicetree\n");
+		ret = -EINVAL;
+		goto failed_init;
+	}
+
+	/*
+	 * imxfb does not support more modes, we choose only the native
+	 * mode.
+	 */
+	fbi->num_modes = 1;
+
+	fbi->mode = devm_kzalloc(&pdev->dev,
+			sizeof(struct imx_fb_videomode), GFP_KERNEL);
+	if (!fbi->mode) {
+		ret = -ENOMEM;
+		of_node_put(display_np);
+		goto failed_init;
+	}
+
+	ret = imxfb_of_read_mode(&pdev->dev, display_np, fbi->mode);
+	of_node_put(display_np);
+	if (ret)
+		goto failed_init;
+
+	/*
+	 * Calculate maximum bytes used per pixel. In most cases this should
+	 * be the same as m->bpp/8
+	 */
+	m = &fbi->mode[0];
+	bytes_per_pixel = (m->bpp + 7) / 8;
+	for (i = 0; i < fbi->num_modes; i++, m++)
+		info->fix.smem_len = max_t(size_t, info->fix.smem_len,
+				m->mode.xres * m->mode.yres * bytes_per_pixel);
+
+	fbi->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
+	if (IS_ERR(fbi->clk_ipg)) {
+		ret = PTR_ERR(fbi->clk_ipg);
+		goto failed_init;
+	}
+
+	/*
+	 * The LCDC controller does not have an enable bit. The
+	 * controller starts directly when the clocks are enabled.
+	 * If the clocks are enabled when the controller is not yet
+	 * programmed with proper register values (enabled at the
+	 * bootloader, for example) then it just goes into some undefined
+	 * state.
+	 * To avoid this issue, let's enable and disable LCDC IPG clock
+	 * so that we force some kind of 'reset' to the LCDC block.
+	 */
+	ret = clk_prepare_enable(fbi->clk_ipg);
+	if (ret)
+		goto failed_init;
+	clk_disable_unprepare(fbi->clk_ipg);
+
+	fbi->clk_ahb = devm_clk_get(&pdev->dev, "ahb");
+	if (IS_ERR(fbi->clk_ahb)) {
+		ret = PTR_ERR(fbi->clk_ahb);
+		goto failed_init;
+	}
+
+	fbi->clk_per = devm_clk_get(&pdev->dev, "per");
+	if (IS_ERR(fbi->clk_per)) {
+		ret = PTR_ERR(fbi->clk_per);
+		goto failed_init;
+	}
+
+	fbi->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(fbi->regs)) {
+		ret = PTR_ERR(fbi->regs);
+		goto failed_init;
+	}
+
+	fbi->map_size = PAGE_ALIGN(info->fix.smem_len);
+	info->screen_buffer = dma_alloc_wc(&pdev->dev, fbi->map_size,
+					   &fbi->map_dma, GFP_KERNEL);
+	if (!info->screen_buffer) {
+		dev_err(&pdev->dev, "Failed to allocate video RAM\n");
+		ret = -ENOMEM;
+		goto failed_init;
+	}
+
+	info->fix.smem_start = fbi->map_dma;
+
+	INIT_LIST_HEAD(&info->modelist);
+	for (i = 0; i < fbi->num_modes; i++) {
+		ret = fb_add_videomode(&fbi->mode[i].mode, &info->modelist);
+		if (ret) {
+			dev_err(&pdev->dev, "Failed to add videomode\n");
+			goto failed_cmap;
+		}
+	}
+
+	/*
+	 * This makes sure that our colour bitfield
+	 * descriptors are correctly initialised.
+	 */
+	imxfb_check_var(&info->var, info);
+
+	/*
+	 * For modes > 8bpp, the color map is bypassed.
+	 * Therefore, 256 entries are enough.
+	 */
+	ret = fb_alloc_cmap(&info->cmap, 256, 0);
+	if (ret < 0)
+		goto failed_cmap;
+
+	imxfb_set_par(info);
+
+	fbi->lcd_pwr = devm_regulator_get(&pdev->dev, "lcd");
+	if (PTR_ERR(fbi->lcd_pwr) == -EPROBE_DEFER) {
+		ret = -EPROBE_DEFER;
+		goto failed_lcd;
+	}
+
+	lcd = devm_lcd_device_register(&pdev->dev, "imxfb-lcd", &pdev->dev, fbi,
+				       &imxfb_lcd_ops);
+	if (IS_ERR(lcd)) {
+		ret = PTR_ERR(lcd);
+		goto failed_lcd;
+	}
+
+	lcd->props.max_contrast = 0xff;
+
+	info->lcd_dev = lcd;
+
+	ret = register_framebuffer(info);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to register framebuffer\n");
+		goto failed_lcd;
+	}
+
+	imxfb_enable_controller(fbi);
+
+	return 0;
+
+failed_lcd:
+	fb_dealloc_cmap(&info->cmap);
+failed_cmap:
+	dma_free_wc(&pdev->dev, fbi->map_size, info->screen_buffer,
+		    fbi->map_dma);
+failed_init:
+	framebuffer_release(info);
+	return ret;
+}
+
+static void imxfb_remove(struct platform_device *pdev)
+{
+	struct fb_info *info = platform_get_drvdata(pdev);
+	struct imxfb_info *fbi = info->par;
+
+	imxfb_disable_controller(fbi);
+
+	unregister_framebuffer(info);
+	fb_dealloc_cmap(&info->cmap);
+	dma_free_wc(&pdev->dev, fbi->map_size, info->screen_buffer,
+		    fbi->map_dma);
+	framebuffer_release(info);
+}
+
+static int imxfb_suspend(struct device *dev)
+{
+	struct fb_info *info = dev_get_drvdata(dev);
+	struct imxfb_info *fbi = info->par;
+
+	imxfb_disable_controller(fbi);
+
+	return 0;
+}
+
+static int imxfb_resume(struct device *dev)
+{
+	struct fb_info *info = dev_get_drvdata(dev);
+	struct imxfb_info *fbi = info->par;
+
+	imxfb_enable_controller(fbi);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(imxfb_pm_ops, imxfb_suspend, imxfb_resume);
+
+static struct platform_driver imxfb_driver = {
+	.driver		= {
+		.name	= DRIVER_NAME,
+		.of_match_table = imxfb_of_dev_id,
+		.pm	= pm_sleep_ptr(&imxfb_pm_ops),
+	},
+	.probe		= imxfb_probe,
+	.remove		= imxfb_remove,
+	.id_table	= imxfb_devtype,
+};
+module_platform_driver(imxfb_driver);
+
+MODULE_DESCRIPTION("Freescale i.MX framebuffer driver");
+MODULE_AUTHOR("Sascha Hauer, Pengutronix");
+MODULE_LICENSE("GPL");
-- 
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