drivers/gpu/drm/exynos/exynos7_drm_decon.c

/* drivers/gpu/drm/exynos/exynos7_drm_decon.c
 *
 * Copyright (C) 2014 Samsung Electronics Co.Ltd
 * Authors:
 *	Akshu Agarwal <akshua@gmail.com>
 *	Ajay Kumar <ajaykumar.rs@samsung.com>
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 *
 */
#include <drm/drmP.h>
#include <drm/exynos_drm.h>

#include <linux/clk.h>
#include <linux/component.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>

#include <video/of_display_timing.h>
#include <video/of_videomode.h>
#include <video/exynos7_decon.h>

#include "exynos_drm_crtc.h"
#include "exynos_drm_plane.h"
#include "exynos_drm_drv.h"
#include "exynos_drm_fbdev.h"
#include "exynos_drm_iommu.h"

/*
 * DECON stands for Display and Enhancement controller.
 */

#define DECON_DEFAULT_FRAMERATE 60
#define MIN_FB_WIDTH_FOR_16WORD_BURST 128

#define WINDOWS_NR	2

struct decon_context {
	struct device			*dev;
	struct drm_device		*drm_dev;
	struct exynos_drm_crtc		*crtc;
	struct exynos_drm_plane		planes[WINDOWS_NR];
	struct clk			*pclk;
	struct clk			*aclk;
	struct clk			*eclk;
	struct clk			*vclk;
	void __iomem			*regs;
	unsigned int			default_win;
	unsigned long			irq_flags;
	bool				i80_if;
	bool				suspended;
	int				pipe;
	wait_queue_head_t		wait_vsync_queue;
	atomic_t			wait_vsync_event;

	struct exynos_drm_panel_info panel;
	struct exynos_drm_display *display;
};

static const struct of_device_id decon_driver_dt_match[] = {
	{.compatible = "samsung,exynos7-decon"},
	{},
};
MODULE_DEVICE_TABLE(of, decon_driver_dt_match);

static void decon_wait_for_vblank(struct exynos_drm_crtc *crtc)
{
	struct decon_context *ctx = crtc->ctx;

	if (ctx->suspended)
		return;

	atomic_set(&ctx->wait_vsync_event, 1);

	/*
	 * wait for DECON to signal VSYNC interrupt or return after
	 * timeout which is set to 50ms (refresh rate of 20).
	 */
	if (!wait_event_timeout(ctx->wait_vsync_queue,
				!atomic_read(&ctx->wait_vsync_event),
				HZ/20))
		DRM_DEBUG_KMS("vblank wait timed out.\n");
}

static void decon_clear_channels(struct exynos_drm_crtc *crtc)
{
	struct decon_context *ctx = crtc->ctx;
	unsigned int win, ch_enabled = 0;

	DRM_DEBUG_KMS("%s\n", __FILE__);

	/* Check if any channel is enabled. */
	for (win = 0; win < WINDOWS_NR; win++) {
		u32 val = readl(ctx->regs + WINCON(win));

		if (val & WINCONx_ENWIN) {
			val &= ~WINCONx_ENWIN;
			writel(val, ctx->regs + WINCON(win));
			ch_enabled = 1;
		}
	}

	/* Wait for vsync, as disable channel takes effect at next vsync */
	if (ch_enabled) {
		unsigned int state = ctx->suspended;

		ctx->suspended = 0;
		decon_wait_for_vblank(ctx->crtc);
		ctx->suspended = state;
	}
}

static int decon_ctx_initialize(struct decon_context *ctx,
			struct drm_device *drm_dev)
{
	struct exynos_drm_private *priv = drm_dev->dev_private;
	int ret;

	ctx->drm_dev = drm_dev;
	ctx->pipe = priv->pipe++;

	ret = drm_iommu_attach_device_if_possible(ctx->crtc, drm_dev, ctx->dev);
	if (ret)
		priv->pipe--;

	return ret;
}

static void decon_ctx_remove(struct decon_context *ctx)
{
	/* detach this sub driver from iommu mapping if supported. */
	if (is_drm_iommu_supported(ctx->drm_dev))
		drm_iommu_detach_device(ctx->drm_dev, ctx->dev);
}

static u32 decon_calc_clkdiv(struct decon_context *ctx,
		const struct drm_display_mode *mode)
{
	unsigned long ideal_clk = mode->htotal * mode->vtotal * mode->vrefresh;
	u32 clkdiv;

	/* Find the clock divider value that gets us closest to ideal_clk */
	clkdiv = DIV_ROUND_UP(clk_get_rate(ctx->vclk), ideal_clk);

	return (clkdiv < 0x100) ? clkdiv : 0xff;
}

static bool decon_mode_fixup(struct exynos_drm_crtc *crtc,
		const struct drm_display_mode *mode,
		struct drm_display_mode *adjusted_mode)
{
	if (adjusted_mode->vrefresh == 0)
		adjusted_mode->vrefresh = DECON_DEFAULT_FRAMERATE;

	return true;
}

static void decon_commit(struct exynos_drm_crtc *crtc)
{
	struct decon_context *ctx = crtc->ctx;
	struct drm_display_mode *mode = &crtc->base.state->adjusted_mode;
	u32 val, clkdiv;

	if (ctx->suspended)
		return;

	/* nothing to do if we haven't set the mode yet */
	if (mode->htotal == 0 || mode->vtotal == 0)
		return;

	if (!ctx->i80_if) {
		int vsync_len, vbpd, vfpd, hsync_len, hbpd, hfpd;
	      /* setup vertical timing values. */
		vsync_len = mode->crtc_vsync_end - mode->crtc_vsync_start;
		vbpd = mode->crtc_vtotal - mode->crtc_vsync_end;
		vfpd = mode->crtc_vsync_start - mode->crtc_vdisplay;

		val = VIDTCON0_VBPD(vbpd - 1) | VIDTCON0_VFPD(vfpd - 1);
		writel(val, ctx->regs + VIDTCON0);

		val = VIDTCON1_VSPW(vsync_len - 1);
		writel(val, ctx->regs + VIDTCON1);

		/* setup horizontal timing values.  */
		hsync_len = mode->crtc_hsync_end - mode->crtc_hsync_start;
		hbpd = mode->crtc_htotal - mode->crtc_hsync_end;
		hfpd = mode->crtc_hsync_start - mode->crtc_hdisplay;

		/* setup horizontal timing values.  */
		val = VIDTCON2_HBPD(hbpd - 1) | VIDTCON2_HFPD(hfpd - 1);
		writel(val, ctx->regs + VIDTCON2);

		val = VIDTCON3_HSPW(hsync_len - 1);
		writel(val, ctx->regs + VIDTCON3);
	}

	/* setup horizontal and vertical display size. */
	val = VIDTCON4_LINEVAL(mode->vdisplay - 1) |
	       VIDTCON4_HOZVAL(mode->hdisplay - 1);
	writel(val, ctx->regs + VIDTCON4);

	writel(mode->vdisplay - 1, ctx->regs + LINECNT_OP_THRESHOLD);

	/*
	 * fields of register with prefix '_F' would be updated
	 * at vsync(same as dma start)
	 */
	val = VIDCON0_ENVID | VIDCON0_ENVID_F;
	writel(val, ctx->regs + VIDCON0);

	clkdiv = decon_calc_clkdiv(ctx, mode);
	if (clkdiv > 1) {
		val = VCLKCON1_CLKVAL_NUM_VCLK(clkdiv - 1);
		writel(val, ctx->regs + VCLKCON1);
		writel(val, ctx->regs + VCLKCON2);
	}

	val = readl(ctx->regs + DECON_UPDATE);
	val |= DECON_UPDATE_STANDALONE_F;
	writel(val, ctx->regs + DECON_UPDATE);
}

static int decon_enable_vblank(struct exynos_drm_crtc *crtc)
{
	struct decon_context *ctx = crtc->ctx;
	u32 val;

	if (ctx->suspended)
		return -EPERM;

	if (!test_and_set_bit(0, &ctx->irq_flags)) {
		val = readl(ctx->regs + VIDINTCON0);

		val |= VIDINTCON0_INT_ENABLE;

		if (!ctx->i80_if) {
			val |= VIDINTCON0_INT_FRAME;
			val &= ~VIDINTCON0_FRAMESEL0_MASK;
			val |= VIDINTCON0_FRAMESEL0_VSYNC;
		}

		writel(val, ctx->regs + VIDINTCON0);
	}

	return 0;
}

static void decon_disable_vblank(struct exynos_drm_crtc *crtc)
{
	struct decon_context *ctx = crtc->ctx;
	u32 val;

	if (ctx->suspended)
		return;

	if (test_and_clear_bit(0, &ctx->irq_flags)) {
		val = readl(ctx->regs + VIDINTCON0);

		val &= ~VIDINTCON0_INT_ENABLE;
		if (!ctx->i80_if)
			val &= ~VIDINTCON0_INT_FRAME;

		writel(val, ctx->regs + VIDINTCON0);
	}
}

static void decon_win_set_pixfmt(struct decon_context *ctx, unsigned int win)
{
	struct exynos_drm_plane *plane = &ctx->planes[win];
	unsigned long val;
	int padding;

	val = readl(ctx->regs + WINCON(win));
	val &= ~WINCONx_BPPMODE_MASK;

	switch (plane->pixel_format) {
	case DRM_FORMAT_RGB565:
		val |= WINCONx_BPPMODE_16BPP_565;
		val |= WINCONx_BURSTLEN_16WORD;
		break;
	case DRM_FORMAT_XRGB8888:
		val |= WINCONx_BPPMODE_24BPP_xRGB;
		val |= WINCONx_BURSTLEN_16WORD;
		break;
	case DRM_FORMAT_XBGR8888:
		val |= WINCONx_BPPMODE_24BPP_xBGR;
		val |= WINCONx_BURSTLEN_16WORD;
		break;
	case DRM_FORMAT_RGBX8888:
		val |= WINCONx_BPPMODE_24BPP_RGBx;
		val |= WINCONx_BURSTLEN_16WORD;
		break;
	case DRM_FORMAT_BGRX8888:
		val |= WINCONx_BPPMODE_24BPP_BGRx;
		val |= WINCONx_BURSTLEN_16WORD;
		break;
	case DRM_FORMAT_ARGB8888:
		val |= WINCONx_BPPMODE_32BPP_ARGB | WINCONx_BLD_PIX |
			WINCONx_ALPHA_SEL;
		val |= WINCONx_BURSTLEN_16WORD;
		break;
	case DRM_FORMAT_ABGR8888:
		val |= WINCONx_BPPMODE_32BPP_ABGR | WINCONx_BLD_PIX |
			WINCONx_ALPHA_SEL;
		val |= WINCONx_BURSTLEN_16WORD;
		break;
	case DRM_FORMAT_RGBA8888:
		val |= WINCONx_BPPMODE_32BPP_RGBA | WINCONx_BLD_PIX |
			WINCONx_ALPHA_SEL;
		val |= WINCONx_BURSTLEN_16WORD;
		break;
	case DRM_FORMAT_BGRA8888:
		val |= WINCONx_BPPMODE_32BPP_BGRA | WINCONx_BLD_PIX |
			WINCONx_ALPHA_SEL;
		val |= WINCONx_BURSTLEN_16WORD;
		break;
	default:
		DRM_DEBUG_KMS("invalid pixel size so using unpacked 24bpp.\n");

		val |= WINCONx_BPPMODE_24BPP_xRGB;
		val |= WINCONx_BURSTLEN_16WORD;
		break;
	}

	DRM_DEBUG_KMS("bpp = %d\n", plane->bpp);

	/*
	 * In case of exynos, setting dma-burst to 16Word causes permanent
	 * tearing for very small buffers, e.g. cursor buffer. Burst Mode
	 * switching which is based on plane size is not recommended as
	 * plane size varies a lot towards the end of the screen and rapid
	 * movement causes unstable DMA which results into iommu crash/tear.
	 */

	padding = (plane->pitch / (plane->bpp >> 3)) - plane->fb_width;
	if (plane->fb_width + padding < MIN_FB_WIDTH_FOR_16WORD_BURST) {
		val &= ~WINCONx_BURSTLEN_MASK;
		val |= WINCONx_BURSTLEN_8WORD;
	}

	writel(val, ctx->regs + WINCON(win));
}

static void decon_win_set_colkey(struct decon_context *ctx, unsigned int win)
{
	unsigned int keycon0 = 0, keycon1 = 0;

	keycon0 = ~(WxKEYCON0_KEYBL_EN | WxKEYCON0_KEYEN_F |
			WxKEYCON0_DIRCON) | WxKEYCON0_COMPKEY(0);

	keycon1 = WxKEYCON1_COLVAL(0xffffffff);

	writel(keycon0, ctx->regs + WKEYCON0_BASE(win));
	writel(keycon1, ctx->regs + WKEYCON1_BASE(win));
}

/**
 * shadow_protect_win() - disable updating values from shadow registers at vsync
 *
 * @win: window to protect registers for
 * @protect: 1 to protect (disable updates)
 */
static void decon_shadow_protect_win(struct decon_context *ctx,
				     unsigned int win, bool protect)
{
	u32 bits, val;

	bits = SHADOWCON_WINx_PROTECT(win);

	val = readl(ctx->regs + SHADOWCON);
	if (protect)
		val |= bits;
	else
		val &= ~bits;
	writel(val, ctx->regs + SHADOWCON);
}

static void decon_win_commit(struct exynos_drm_crtc *crtc, unsigned int win)
{
	struct decon_context *ctx = crtc->ctx;
	struct drm_display_mode *mode = &crtc->base.state->adjusted_mode;
	struct exynos_drm_plane *plane;
	int padding;
	unsigned long val, alpha;
	unsigned int last_x;
	unsigned int last_y;

	if (ctx->suspended)
		return;

	if (win < 0 || win >= WINDOWS_NR)
		return;

	plane = &ctx->planes[win];

	if (ctx->suspended)
		return;

	/*
	 * SHADOWCON/PRTCON register is used for enabling timing.
	 *
	 * for example, once only width value of a register is set,
	 * if the dma is started then decon hardware could malfunction so
	 * with protect window setting, the register fields with prefix '_F'
	 * wouldn't be updated at vsync also but updated once unprotect window
	 * is set.
	 */

	/* protect windows */
	decon_shadow_protect_win(ctx, win, true);

	/* buffer start address */
	val = (unsigned long)plane->dma_addr[0];
	writel(val, ctx->regs + VIDW_BUF_START(win));

	padding = (plane->pitch / (plane->bpp >> 3)) - plane->fb_width;

	/* buffer size */
	writel(plane->fb_width + padding, ctx->regs + VIDW_WHOLE_X(win));
	writel(plane->fb_height, ctx->regs + VIDW_WHOLE_Y(win));

	/* offset from the start of the buffer to read */
	writel(plane->src_x, ctx->regs + VIDW_OFFSET_X(win));
	writel(plane->src_y, ctx->regs + VIDW_OFFSET_Y(win));

	DRM_DEBUG_KMS("start addr = 0x%lx\n",
			(unsigned long)val);
	DRM_DEBUG_KMS("ovl_width = %d, ovl_height = %d\n",
			plane->crtc_width, plane->crtc_height);

	/*
	 * OSD position.
	 * In case the window layout goes of LCD layout, DECON fails.
	 */
	if ((plane->crtc_x + plane->crtc_width) > mode->hdisplay)
		plane->crtc_x = mode->hdisplay - plane->crtc_width;
	if ((plane->crtc_y + plane->crtc_height) > mode->vdisplay)
		plane->crtc_y = mode->vdisplay - plane->crtc_height;

	val = VIDOSDxA_TOPLEFT_X(plane->crtc_x) |
		VIDOSDxA_TOPLEFT_Y(plane->crtc_y);
	writel(val, ctx->regs + VIDOSD_A(win));

	last_x = plane->crtc_x + plane->crtc_width;
	if (last_x)
		last_x--;
	last_y = plane->crtc_y + plane->crtc_height;
	if (last_y)
		last_y--;

	val = VIDOSDxB_BOTRIGHT_X(last_x) | VIDOSDxB_BOTRIGHT_Y(last_y);

	writel(val, ctx->regs + VIDOSD_B(win));

	DRM_DEBUG_KMS("osd pos: tx = %d, ty = %d, bx = %d, by = %d\n",
			plane->crtc_x, plane->crtc_y, last_x, last_y);

	/* OSD alpha */
	alpha = VIDOSDxC_ALPHA0_R_F(0x0) |
			VIDOSDxC_ALPHA0_G_F(0x0) |
			VIDOSDxC_ALPHA0_B_F(0x0);

	writel(alpha, ctx->regs + VIDOSD_C(win));

	alpha = VIDOSDxD_ALPHA1_R_F(0xff) |
			VIDOSDxD_ALPHA1_G_F(0xff) |
			VIDOSDxD_ALPHA1_B_F(0xff);

	writel(alpha, ctx->regs + VIDOSD_D(win));

	decon_win_set_pixfmt(ctx, win);

	/* hardware window 0 doesn't support color key. */
	if (win != 0)
		decon_win_set_colkey(ctx, win);

	/* wincon */
	val = readl(ctx->regs + WINCON(win));
	val |= WINCONx_TRIPLE_BUF_MODE;
	val |= WINCONx_ENWIN;
	writel(val, ctx->regs + WINCON(win));

	/* Enable DMA channel and unprotect windows */
	decon_shadow_protect_win(ctx, win, false);

	val = readl(ctx->regs + DECON_UPDATE);
	val |= DECON_UPDATE_STANDALONE_F;
	writel(val, ctx->regs + DECON_UPDATE);
}

static void decon_win_disable(struct exynos_drm_crtc *crtc, unsigned int win)
{
	struct decon_context *ctx = crtc->ctx;
	struct exynos_drm_plane *plane;
	u32 val;

	if (win < 0 || win >= WINDOWS_NR)
		return;

	plane = &ctx->planes[win];

	if (ctx->suspended)
		return;

	/* protect windows */
	decon_shadow_protect_win(ctx, win, true);

	/* wincon */
	val = readl(ctx->regs + WINCON(win));
	val &= ~WINCONx_ENWIN;
	writel(val, ctx->regs + WINCON(win));

	/* unprotect windows */
	decon_shadow_protect_win(ctx, win, false);

	val = readl(ctx->regs + DECON_UPDATE);
	val |= DECON_UPDATE_STANDALONE_F;
	writel(val, ctx->regs + DECON_UPDATE);
}

static void decon_init(struct decon_context *ctx)
{
	u32 val;

	writel(VIDCON0_SWRESET, ctx->regs + VIDCON0);

	val = VIDOUTCON0_DISP_IF_0_ON;
	if (!ctx->i80_if)
		val |= VIDOUTCON0_RGBIF;
	writel(val, ctx->regs + VIDOUTCON0);

	writel(VCLKCON0_CLKVALUP | VCLKCON0_VCLKFREE, ctx->regs + VCLKCON0);

	if (!ctx->i80_if)
		writel(VIDCON1_VCLK_HOLD, ctx->regs + VIDCON1(0));
}

static void decon_enable(struct exynos_drm_crtc *crtc)
{
	struct decon_context *ctx = crtc->ctx;
	int ret;

	if (!ctx->suspended)
		return;

	ctx->suspended = false;

	pm_runtime_get_sync(ctx->dev);

	ret = clk_prepare_enable(ctx->pclk);
	if (ret < 0) {
		DRM_ERROR("Failed to prepare_enable the pclk [%d]\n", ret);
		return;
	}

	ret = clk_prepare_enable(ctx->aclk);
	if (ret < 0) {
		DRM_ERROR("Failed to prepare_enable the aclk [%d]\n", ret);
		return;
	}

	ret = clk_prepare_enable(ctx->eclk);
	if  (ret < 0) {
		DRM_ERROR("Failed to prepare_enable the eclk [%d]\n", ret);
		return;
	}

	ret = clk_prepare_enable(ctx->vclk);
	if  (ret < 0) {
		DRM_ERROR("Failed to prepare_enable the vclk [%d]\n", ret);
		return;
	}

	decon_init(ctx);

	/* if vblank was enabled status, enable it again. */
	if (test_and_clear_bit(0, &ctx->irq_flags))
		decon_enable_vblank(ctx->crtc);

	decon_commit(ctx->crtc);
}

static void decon_disable(struct exynos_drm_crtc *crtc)
{
	struct decon_context *ctx = crtc->ctx;
	int i;

	if (ctx->suspended)
		return;

	/*
	 * We need to make sure that all windows are disabled before we
	 * suspend that connector. Otherwise we might try to scan from
	 * a destroyed buffer later.
	 */
	for (i = 0; i < WINDOWS_NR; i++)
		decon_win_disable(crtc, i);

	clk_disable_unprepare(ctx->vclk);
	clk_disable_unprepare(ctx->eclk);
	clk_disable_unprepare(ctx->aclk);
	clk_disable_unprepare(ctx->pclk);

	pm_runtime_put_sync(ctx->dev);

	ctx->suspended = true;
}

static const struct exynos_drm_crtc_ops decon_crtc_ops = {
	.enable = decon_enable,
	.disable = decon_disable,
	.mode_fixup = decon_mode_fixup,
	.commit = decon_commit,
	.enable_vblank = decon_enable_vblank,
	.disable_vblank = decon_disable_vblank,
	.wait_for_vblank = decon_wait_for_vblank,
	.win_commit = decon_win_commit,
	.win_disable = decon_win_disable,
	.clear_channels = decon_clear_channels,
};


static irqreturn_t decon_irq_handler(int irq, void *dev_id)
{
	struct decon_context *ctx = (struct decon_context *)dev_id;
	u32 val, clear_bit;

	val = readl(ctx->regs + VIDINTCON1);

	clear_bit = ctx->i80_if ? VIDINTCON1_INT_I80 : VIDINTCON1_INT_FRAME;
	if (val & clear_bit)
		writel(clear_bit, ctx->regs + VIDINTCON1);

	/* check the crtc is detached already from encoder */
	if (ctx->pipe < 0 || !ctx->drm_dev)
		goto out;

	if (!ctx->i80_if) {
		drm_handle_vblank(ctx->drm_dev, ctx->pipe);
		exynos_drm_crtc_finish_pageflip(ctx->drm_dev, ctx->pipe);

		/* set wait vsync event to zero and wake up queue. */
		if (atomic_read(&ctx->wait_vsync_event)) {
			atomic_set(&ctx->wait_vsync_event, 0);
			wake_up(&ctx->wait_vsync_queue);
		}
	}
out:
	return IRQ_HANDLED;
}

static int decon_bind(struct device *dev, struct device *master, void *data)
{
	struct decon_context *ctx = dev_get_drvdata(dev);
	struct drm_device *drm_dev = data;
	struct exynos_drm_plane *exynos_plane;
	enum drm_plane_type type;
	unsigned int zpos;
	int ret;

	ret = decon_ctx_initialize(ctx, drm_dev);
	if (ret) {
		DRM_ERROR("decon_ctx_initialize failed.\n");
		return ret;
	}

	for (zpos = 0; zpos < WINDOWS_NR; zpos++) {
		type = (zpos == ctx->default_win) ? DRM_PLANE_TYPE_PRIMARY :
						DRM_PLANE_TYPE_OVERLAY;
		ret = exynos_plane_init(drm_dev, &ctx->planes[zpos],
					1 << ctx->pipe, type, zpos);
		if (ret)
			return ret;
	}

	exynos_plane = &ctx->planes[ctx->default_win];
	ctx->crtc = exynos_drm_crtc_create(drm_dev, &exynos_plane->base,
					   ctx->pipe, EXYNOS_DISPLAY_TYPE_LCD,
					   &decon_crtc_ops, ctx);
	if (IS_ERR(ctx->crtc)) {
		decon_ctx_remove(ctx);
		return PTR_ERR(ctx->crtc);
	}

	if (ctx->display)
		exynos_drm_create_enc_conn(drm_dev, ctx->display);

	return 0;

}

static void decon_unbind(struct device *dev, struct device *master,
			void *data)
{
	struct decon_context *ctx = dev_get_drvdata(dev);

	decon_disable(ctx->crtc);

	if (ctx->display)
		exynos_dpi_remove(ctx->display);

	decon_ctx_remove(ctx);
}

static const struct component_ops decon_component_ops = {
	.bind	= decon_bind,
	.unbind = decon_unbind,
};

static int decon_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct decon_context *ctx;
	struct device_node *i80_if_timings;
	struct resource *res;
	int ret;

	if (!dev->of_node)
		return -ENODEV;

	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
	if (!ctx)
		return -ENOMEM;

	ctx->dev = dev;
	ctx->suspended = true;

	i80_if_timings = of_get_child_by_name(dev->of_node, "i80-if-timings");
	if (i80_if_timings)
		ctx->i80_if = true;
	of_node_put(i80_if_timings);

	ctx->regs = of_iomap(dev->of_node, 0);
	if (!ctx->regs)
		return -ENOMEM;

	ctx->pclk = devm_clk_get(dev, "pclk_decon0");
	if (IS_ERR(ctx->pclk)) {
		dev_err(dev, "failed to get bus clock pclk\n");
		ret = PTR_ERR(ctx->pclk);
		goto err_iounmap;
	}

	ctx->aclk = devm_clk_get(dev, "aclk_decon0");
	if (IS_ERR(ctx->aclk)) {
		dev_err(dev, "failed to get bus clock aclk\n");
		ret = PTR_ERR(ctx->aclk);
		goto err_iounmap;
	}

	ctx->eclk = devm_clk_get(dev, "decon0_eclk");
	if (IS_ERR(ctx->eclk)) {
		dev_err(dev, "failed to get eclock\n");
		ret = PTR_ERR(ctx->eclk);
		goto err_iounmap;
	}

	ctx->vclk = devm_clk_get(dev, "decon0_vclk");
	if (IS_ERR(ctx->vclk)) {
		dev_err(dev, "failed to get vclock\n");
		ret = PTR_ERR(ctx->vclk);
		goto err_iounmap;
	}

	res = platform_get_resource_byname(pdev, IORESOURCE_IRQ,
					   ctx->i80_if ? "lcd_sys" : "vsync");
	if (!res) {
		dev_err(dev, "irq request failed.\n");
		ret = -ENXIO;
		goto err_iounmap;
	}

	ret = devm_request_irq(dev, res->start, decon_irq_handler,
							0, "drm_decon", ctx);
	if (ret) {
		dev_err(dev, "irq request failed.\n");
		goto err_iounmap;
	}

	init_waitqueue_head(&ctx->wait_vsync_queue);
	atomic_set(&ctx->wait_vsync_event, 0);

	platform_set_drvdata(pdev, ctx);

	ctx->display = exynos_dpi_probe(dev);
	if (IS_ERR(ctx->display)) {
		ret = PTR_ERR(ctx->display);
		goto err_iounmap;
	}

	pm_runtime_enable(dev);

	ret = component_add(dev, &decon_component_ops);
	if (ret)
		goto err_disable_pm_runtime;

	return ret;

err_disable_pm_runtime:
	pm_runtime_disable(dev);

err_iounmap:
	iounmap(ctx->regs);

	return ret;
}

static int decon_remove(struct platform_device *pdev)
{
	struct decon_context *ctx = dev_get_drvdata(&pdev->dev);

	pm_runtime_disable(&pdev->dev);

	iounmap(ctx->regs);

	component_del(&pdev->dev, &decon_component_ops);

	return 0;
}

struct platform_driver decon_driver = {
	.probe		= decon_probe,
	.remove		= decon_remove,
	.driver		= {
		.name	= "exynos-decon",
		.of_match_table = decon_driver_dt_match,
	},
};