drm/imx/lcdc: Implement DRM driver for imx25

Add support for the LCD Controller found on i.MX21 and i.MX25.

It targets to be a drop in replacement for the imx-fb driver.

[ukl: Rebase to a newer kernel version, various smaller fixes and
improvements]
Signed-off-by: Marian Cichy <m.cichy@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230306115249.2223042-2-u.kleine-koenig@pengutronix.deSigned-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230306115249.2223042-3-u.kleine-koenig@pengutronix.de

drivers/gpu/drm/imx/Kconfig

@@ -2,3 +2,4 @@
 
 source "drivers/gpu/drm/imx/dcss/Kconfig"
 source "drivers/gpu/drm/imx/ipuv3/Kconfig"
+source "drivers/gpu/drm/imx/lcdc/Kconfig"

drivers/gpu/drm/imx/Makefile

@@ -2,3 +2,4 @@
 
 obj-$(CONFIG_DRM_IMX_DCSS) += dcss/
 obj-$(CONFIG_DRM_IMX) += ipuv3/
+obj-$(CONFIG_DRM_IMX_LCDC) += lcdc/

drivers/gpu/drm/imx/lcdc/Kconfig

+config DRM_IMX_LCDC
+      tristate "Freescale i.MX LCDC displays"
+      depends on DRM && (ARCH_MXC || COMPILE_TEST)
+      select DRM_GEM_DMA_HELPER
+      select DRM_KMS_HELPER
+      help
+        Found on i.MX1, i.MX21, i.MX25 and i.MX27.

drivers/gpu/drm/imx/lcdc/Makefile

+obj-$(CONFIG_DRM_IMX_LCDC) += imx-lcdc.o

drivers/gpu/drm/imx/lcdc/imx-lcdc.c

+// SPDX-License-Identifier: GPL-2.0-only
+// SPDX-FileCopyrightText: 2020 Marian Cichy <M.Cichy@pengutronix.de>
+
+#include <drm/drm_bridge_connector.h>
+#include <drm/drm_damage_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fbdev_generic.h>
+#include <drm/drm_fb_dma_helper.h>
+#include <drm/drm_fourcc.h>
+#include <drm/drm_framebuffer.h>
+#include <drm/drm_gem_atomic_helper.h>
+#include <drm/drm_gem_dma_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_of.h>
+#include <drm/drm_probe_helper.h>
+#include <drm/drm_simple_kms_helper.h>
+#include <drm/drm_vblank.h>
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/dma-mapping.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+#define IMX21LCDC_LSSAR         0x0000 /* LCDC Screen Start Address Register */
+#define IMX21LCDC_LSR           0x0004 /* LCDC Size Register */
+#define IMX21LCDC_LVPWR         0x0008 /* LCDC Virtual Page Width Register */
+#define IMX21LCDC_LCPR          0x000C /* LCDC Cursor Position Register */
+#define IMX21LCDC_LCWHB         0x0010 /* LCDC Cursor Width Height and Blink Register*/
+#define IMX21LCDC_LCCMR         0x0014 /* LCDC Color Cursor Mapping Register */
+#define IMX21LCDC_LPCR          0x0018 /* LCDC Panel Configuration Register */
+#define IMX21LCDC_LHCR          0x001C /* LCDC Horizontal Configuration Register */
+#define IMX21LCDC_LVCR          0x0020 /* LCDC Vertical Configuration Register */
+#define IMX21LCDC_LPOR          0x0024 /* LCDC Panning Offset Register */
+#define IMX21LCDC_LSCR          0x0028 /* LCDC Sharp Configuration Register */
+#define IMX21LCDC_LPCCR         0x002C /* LCDC PWM Contrast Control Register */
+#define IMX21LCDC_LDCR          0x0030 /* LCDC DMA Control Register */
+#define IMX21LCDC_LRMCR         0x0034 /* LCDC Refresh Mode Control Register */
+#define IMX21LCDC_LICR          0x0038 /* LCDC Interrupt Configuration Register */
+#define IMX21LCDC_LIER          0x003C /* LCDC Interrupt Enable Register */
+#define IMX21LCDC_LISR          0x0040 /* LCDC Interrupt Status Register */
+#define IMX21LCDC_LGWSAR        0x0050 /* LCDC Graphic Window Start Address Register */
+#define IMX21LCDC_LGWSR         0x0054 /* LCDC Graph Window Size Register */
+#define IMX21LCDC_LGWVPWR       0x0058 /* LCDC Graphic Window Virtual Page Width Register */
+#define IMX21LCDC_LGWPOR        0x005C /* LCDC Graphic Window Panning Offset Register */
+#define IMX21LCDC_LGWPR         0x0060 /* LCDC Graphic Window Position Register */
+#define IMX21LCDC_LGWCR         0x0064 /* LCDC Graphic Window Control Register */
+#define IMX21LCDC_LGWDCR        0x0068 /* LCDC Graphic Window DMA Control Register */
+#define IMX21LCDC_LAUSCR        0x0080 /* LCDC AUS Mode Control Register */
+#define IMX21LCDC_LAUSCCR       0x0084 /* LCDC AUS Mode Cursor Control Register */
+#define IMX21LCDC_BGLUT         0x0800 /* Background Lookup Table */
+#define IMX21LCDC_GWLUT         0x0C00 /* Graphic Window Lookup Table */
+
+#define IMX21LCDC_LCPR_CC0 BIT(30) /* Cursor Control Bit 0 */
+#define IMX21LCDC_LCPR_CC1 BIT(31) /* Cursor Control Bit 1 */
+
+/* Values HSYNC, VSYNC and Framesize Register */
+#define IMX21LCDC_LHCR_HWIDTH		GENMASK(31, 26)
+#define IMX21LCDC_LHCR_HFPORCH		GENMASK(15, 8)		/* H_WAIT_1 in the i.MX25 Reference manual */
+#define IMX21LCDC_LHCR_HBPORCH		GENMASK(7, 0)		/* H_WAIT_2 in the i.MX25 Reference manual */
+
+#define IMX21LCDC_LVCR_VWIDTH		GENMASK(31, 26)
+#define IMX21LCDC_LVCR_VFPORCH		GENMASK(15, 8)		/* V_WAIT_1 in the i.MX25 Reference manual */
+#define IMX21LCDC_LVCR_VBPORCH		GENMASK(7, 0)		/* V_WAIT_2 in the i.MX25 Reference manual */
+
+#define IMX21LCDC_LSR_XMAX		GENMASK(25, 20)
+#define IMX21LCDC_LSR_YMAX		GENMASK(9, 0)
+
+/* Values for LPCR Register */
+#define IMX21LCDC_LPCR_PCD		GENMASK(5, 0)
+#define IMX21LCDC_LPCR_SHARP		BIT(6)
+#define IMX21LCDC_LPCR_SCLKSEL		BIT(7)
+#define IMX21LCDC_LPCR_ACD		GENMASK(14, 8)
+#define IMX21LCDC_LPCR_ACDSEL		BIT(15)
+#define IMX21LCDC_LPCR_REV_VS		BIT(16)
+#define IMX21LCDC_LPCR_SWAP_SEL		BIT(17)
+#define IMX21LCDC_LPCR_END_SEL		BIT(18)
+#define IMX21LCDC_LPCR_SCLKIDLE		BIT(19)
+#define IMX21LCDC_LPCR_OEPOL		BIT(20)
+#define IMX21LCDC_LPCR_CLKPOL		BIT(21)
+#define IMX21LCDC_LPCR_LPPOL		BIT(22)
+#define IMX21LCDC_LPCR_FLMPOL		BIT(23)
+#define IMX21LCDC_LPCR_PIXPOL		BIT(24)
+#define IMX21LCDC_LPCR_BPIX		GENMASK(27, 25)
+#define IMX21LCDC_LPCR_PBSIZ		GENMASK(29, 28)
+#define IMX21LCDC_LPCR_COLOR		BIT(30)
+#define IMX21LCDC_LPCR_TFT		BIT(31)
+
+#define INTR_EOF BIT(1) /* VBLANK Interrupt Bit */
+
+#define BPP_RGB565	0x05
+#define BPP_XRGB8888	0x07
+
+#define LCDC_MIN_XRES 64
+#define LCDC_MIN_YRES 64
+
+#define LCDC_MAX_XRES 1024
+#define LCDC_MAX_YRES 1024
+
+struct imx_lcdc {
+	struct drm_device drm;
+	struct drm_simple_display_pipe pipe;
+	struct drm_connector *connector;
+	void __iomem *base;
+
+	struct clk *clk_ipg;
+	struct clk *clk_ahb;
+	struct clk *clk_per;
+};
+
+static const u32 imx_lcdc_formats[] = {
+	DRM_FORMAT_RGB565, DRM_FORMAT_XRGB8888,
+};
+
+static inline struct imx_lcdc *imx_lcdc_from_drmdev(struct drm_device *drm)
+{
+	return container_of(drm, struct imx_lcdc, drm);
+}
+
+static unsigned int imx_lcdc_get_format(unsigned int drm_format)
+{
+	switch (drm_format) {
+	default:
+		DRM_WARN("Format not supported - fallback to XRGB8888\n");
+		fallthrough;
+
+	case DRM_FORMAT_XRGB8888:
+		return BPP_XRGB8888;
+
+	case DRM_FORMAT_RGB565:
+		return BPP_RGB565;
+	}
+}
+
+static void imx_lcdc_update_hw_registers(struct drm_simple_display_pipe *pipe,
+					 struct drm_plane_state *old_state,
+					 bool mode_set)
+{
+	struct drm_crtc *crtc = &pipe->crtc;
+	struct drm_plane_state *new_state = pipe->plane.state;
+	struct drm_framebuffer *fb = new_state->fb;
+	struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(pipe->crtc.dev);
+	u32 lpcr, lvcr, lhcr;
+	u32 framesize;
+	dma_addr_t addr;
+
+	addr = drm_fb_dma_get_gem_addr(fb, new_state, 0);
+	/* The LSSAR register specifies the LCD screen start address (SSA). */
+	writel(addr, lcdc->base + IMX21LCDC_LSSAR);
+
+	if (!mode_set)
+		return;
+
+	/* Disable PER clock to make register write possible */
+	if (old_state && old_state->crtc && old_state->crtc->enabled)
+		clk_disable_unprepare(lcdc->clk_per);
+
+	/* Framesize */
+	framesize = FIELD_PREP(IMX21LCDC_LSR_XMAX, crtc->mode.hdisplay >> 4) |
+		FIELD_PREP(IMX21LCDC_LSR_YMAX, crtc->mode.vdisplay);
+	writel(framesize, lcdc->base + IMX21LCDC_LSR);
+
+	/* HSYNC */
+	lhcr = FIELD_PREP(IMX21LCDC_LHCR_HFPORCH, crtc->mode.hsync_start - crtc->mode.hdisplay - 1) |
+		FIELD_PREP(IMX21LCDC_LHCR_HWIDTH, crtc->mode.hsync_end - crtc->mode.hsync_start - 1) |
+		FIELD_PREP(IMX21LCDC_LHCR_HBPORCH, crtc->mode.htotal - crtc->mode.hsync_end - 3);
+	writel(lhcr, lcdc->base + IMX21LCDC_LHCR);
+
+	/* VSYNC */
+	lvcr = FIELD_PREP(IMX21LCDC_LVCR_VFPORCH, crtc->mode.vsync_start - crtc->mode.vdisplay) |
+		FIELD_PREP(IMX21LCDC_LVCR_VWIDTH, crtc->mode.vsync_end - crtc->mode.vsync_start) |
+		FIELD_PREP(IMX21LCDC_LVCR_VBPORCH, crtc->mode.vtotal - crtc->mode.vsync_end);
+	writel(lvcr, lcdc->base + IMX21LCDC_LVCR);
+
+	lpcr = readl(lcdc->base + IMX21LCDC_LPCR);
+	lpcr &= ~IMX21LCDC_LPCR_BPIX;
+	lpcr |= FIELD_PREP(IMX21LCDC_LPCR_BPIX, imx_lcdc_get_format(fb->format->format));
+	writel(lpcr, lcdc->base + IMX21LCDC_LPCR);
+
+	/* Virtual Page Width */
+	writel(new_state->fb->pitches[0] / 4, lcdc->base + IMX21LCDC_LVPWR);
+
+	/* Enable PER clock */
+	if (new_state->crtc->enabled)
+		clk_prepare_enable(lcdc->clk_per);
+}
+
+static void imx_lcdc_pipe_enable(struct drm_simple_display_pipe *pipe,
+				 struct drm_crtc_state *crtc_state,
+				 struct drm_plane_state *plane_state)
+{
+	int ret;
+	int clk_div;
+	int bpp;
+	struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(pipe->crtc.dev);
+	struct drm_display_mode *mode = &pipe->crtc.mode;
+	struct drm_display_info *disp_info = &lcdc->connector->display_info;
+	const int hsync_pol = (mode->flags & DRM_MODE_FLAG_PHSYNC) ? 0 : 1;
+	const int vsync_pol = (mode->flags & DRM_MODE_FLAG_PVSYNC) ? 0 : 1;
+	const int data_enable_pol =
+		(disp_info->bus_flags & DRM_BUS_FLAG_DE_HIGH) ? 0 : 1;
+	const int clk_pol =
+		(disp_info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE) ? 0 : 1;
+
+	clk_div = DIV_ROUND_CLOSEST_ULL(clk_get_rate(lcdc->clk_per),
+					mode->clock * 1000);
+	bpp = imx_lcdc_get_format(plane_state->fb->format->format);
+
+	writel(FIELD_PREP(IMX21LCDC_LPCR_PCD, clk_div - 1) |
+	       FIELD_PREP(IMX21LCDC_LPCR_LPPOL, hsync_pol) |
+	       FIELD_PREP(IMX21LCDC_LPCR_FLMPOL, vsync_pol) |
+	       FIELD_PREP(IMX21LCDC_LPCR_OEPOL, data_enable_pol) |
+	       FIELD_PREP(IMX21LCDC_LPCR_TFT, 1) |
+	       FIELD_PREP(IMX21LCDC_LPCR_COLOR, 1) |
+	       FIELD_PREP(IMX21LCDC_LPCR_PBSIZ, 3) |
+	       FIELD_PREP(IMX21LCDC_LPCR_BPIX, bpp) |
+	       FIELD_PREP(IMX21LCDC_LPCR_SCLKSEL, 1) |
+	       FIELD_PREP(IMX21LCDC_LPCR_PIXPOL, 0) |
+	       FIELD_PREP(IMX21LCDC_LPCR_CLKPOL, clk_pol),
+	       lcdc->base + IMX21LCDC_LPCR);
+
+	/* 0px panning offset */
+	writel(0x00000000, lcdc->base + IMX21LCDC_LPOR);
+
+	/* disable hardware cursor */
+	writel(readl(lcdc->base + IMX21LCDC_LCPR) & ~(IMX21LCDC_LCPR_CC0 | IMX21LCDC_LCPR_CC1),
+	       lcdc->base + IMX21LCDC_LCPR);
+
+	ret = clk_prepare_enable(lcdc->clk_ipg);
+	if (ret) {
+		dev_err(pipe->crtc.dev->dev, "Cannot enable ipg clock: %pe\n", ERR_PTR(ret));
+		return;
+	}
+	ret = clk_prepare_enable(lcdc->clk_ahb);
+	if (ret) {
+		dev_err(pipe->crtc.dev->dev, "Cannot enable ahb clock: %pe\n", ERR_PTR(ret));
+
+		clk_disable_unprepare(lcdc->clk_ipg);
+
+		return;
+	}
+
+	imx_lcdc_update_hw_registers(pipe, NULL, true);
+
+	/* Enable VBLANK Interrupt */
+	writel(INTR_EOF, lcdc->base + IMX21LCDC_LIER);
+}
+
+static void imx_lcdc_pipe_disable(struct drm_simple_display_pipe *pipe)
+{
+	struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(pipe->crtc.dev);
+	struct drm_crtc *crtc = &lcdc->pipe.crtc;
+	struct drm_pending_vblank_event *event;
+
+	clk_disable_unprepare(lcdc->clk_ahb);
+	clk_disable_unprepare(lcdc->clk_ipg);
+
+	if (pipe->crtc.enabled)
+		clk_disable_unprepare(lcdc->clk_per);
+
+	spin_lock_irq(&lcdc->drm.event_lock);
+	event = crtc->state->event;
+	if (event) {
+		crtc->state->event = NULL;
+		drm_crtc_send_vblank_event(crtc, event);
+	}
+	spin_unlock_irq(&lcdc->drm.event_lock);
+
+	/* Disable VBLANK Interrupt */
+	writel(0, lcdc->base + IMX21LCDC_LIER);
+}
+
+static int imx_lcdc_pipe_check(struct drm_simple_display_pipe *pipe,
+			       struct drm_plane_state *plane_state,
+			       struct drm_crtc_state *crtc_state)
+{
+	const struct drm_display_mode *mode = &crtc_state->mode;
+	const struct drm_display_mode *old_mode = &pipe->crtc.state->mode;
+
+	if (mode->hdisplay < LCDC_MIN_XRES || mode->hdisplay > LCDC_MAX_XRES ||
+	    mode->vdisplay < LCDC_MIN_YRES || mode->vdisplay > LCDC_MAX_YRES ||
+	    mode->hdisplay % 0x10) { /* must be multiple of 16 */
+		drm_err(pipe->crtc.dev, "unsupported display mode (%u x %u)\n",
+			mode->hdisplay, mode->vdisplay);
+		return -EINVAL;
+	}
+
+	crtc_state->mode_changed =
+		old_mode->hdisplay != mode->hdisplay ||
+		old_mode->vdisplay != mode->vdisplay;
+
+	return 0;
+}
+
+static void imx_lcdc_pipe_update(struct drm_simple_display_pipe *pipe,
+				 struct drm_plane_state *old_state)
+{
+	struct drm_crtc *crtc = &pipe->crtc;
+	struct drm_pending_vblank_event *event = crtc->state->event;
+	struct drm_plane_state *new_state = pipe->plane.state;
+	struct drm_framebuffer *fb = new_state->fb;
+	struct drm_framebuffer *old_fb = old_state->fb;
+	struct drm_crtc *old_crtc = old_state->crtc;
+	bool mode_changed = false;
+
+	if (old_fb && old_fb->format != fb->format)
+		mode_changed = true;
+	else if (old_crtc != crtc)
+		mode_changed = true;
+
+	imx_lcdc_update_hw_registers(pipe, old_state, mode_changed);
+
+	if (event) {
+		crtc->state->event = NULL;
+
+		spin_lock_irq(&crtc->dev->event_lock);
+
+		if (crtc->state->active && drm_crtc_vblank_get(crtc) == 0)
+			drm_crtc_arm_vblank_event(crtc, event);
+		else
+			drm_crtc_send_vblank_event(crtc, event);
+
+		spin_unlock_irq(&crtc->dev->event_lock);
+	}
+}
+
+static const struct drm_simple_display_pipe_funcs imx_lcdc_pipe_funcs = {
+	.enable = imx_lcdc_pipe_enable,
+	.disable = imx_lcdc_pipe_disable,
+	.check = imx_lcdc_pipe_check,
+	.update = imx_lcdc_pipe_update,
+};
+
+static const struct drm_mode_config_funcs imx_lcdc_mode_config_funcs = {
+	.fb_create = drm_gem_fb_create_with_dirty,
+	.atomic_check = drm_atomic_helper_check,
+	.atomic_commit = drm_atomic_helper_commit,
+};
+
+static const struct drm_mode_config_helper_funcs imx_lcdc_mode_config_helpers = {
+	.atomic_commit_tail = drm_atomic_helper_commit_tail_rpm,
+};
+
+static void imx_lcdc_release(struct drm_device *drm)
+{
+	struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(drm);
+
+	drm_kms_helper_poll_fini(drm);
+	kfree(lcdc);
+}
+
+DEFINE_DRM_GEM_DMA_FOPS(imx_lcdc_drm_fops);
+
+static struct drm_driver imx_lcdc_drm_driver = {
+	.driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
+	.fops = &imx_lcdc_drm_fops,
+	DRM_GEM_DMA_DRIVER_OPS_VMAP,
+	.release = imx_lcdc_release,
+	.name = "imx-lcdc",
+	.desc = "i.MX LCDC driver",
+	.date = "20200716",
+};
+
+static const struct of_device_id imx_lcdc_of_dev_id[] = {
+	{
+		.compatible = "fsl,imx21-lcdc",
+	},
+	{
+		.compatible = "fsl,imx25-lcdc",
+	},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, imx_lcdc_of_dev_id);
+
+static irqreturn_t imx_lcdc_irq_handler(int irq, void *arg)
+{
+	struct imx_lcdc *lcdc = arg;
+	struct drm_crtc *crtc = &lcdc->pipe.crtc;
+	unsigned int status;
+
+	status = readl(lcdc->base + IMX21LCDC_LISR);
+
+	if (status & INTR_EOF) {
+		drm_crtc_handle_vblank(crtc);
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
+}
+
+static int imx_lcdc_probe(struct platform_device *pdev)
+{
+	struct imx_lcdc *lcdc;
+	struct drm_device *drm;
+	struct drm_bridge *bridge;
+	int irq;
+	int ret;
+	struct device *dev = &pdev->dev;
+
+	lcdc = devm_drm_dev_alloc(dev, &imx_lcdc_drm_driver,
+				  struct imx_lcdc, drm);
+	if (!lcdc)
+		return -ENOMEM;
+
+	drm = &lcdc->drm;
+
+	lcdc->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(lcdc->base))
+		return dev_err_probe(dev, PTR_ERR(lcdc->base), "Cannot get IO memory\n");
+
+	bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
+	if (IS_ERR(bridge))
+		return dev_err_probe(dev, PTR_ERR(bridge), "Failed to find bridge\n");
+
+	/* Get Clocks */
+	lcdc->clk_ipg = devm_clk_get(dev, "ipg");
+	if (IS_ERR(lcdc->clk_ipg))
+		return dev_err_probe(dev, PTR_ERR(lcdc->clk_ipg), "Failed to get %s clk\n", "ipg");
+
+	lcdc->clk_ahb = devm_clk_get(dev, "ahb");
+	if (IS_ERR(lcdc->clk_ahb))
+		return dev_err_probe(dev, PTR_ERR(lcdc->clk_ahb), "Failed to get %s clk\n", "ahb");
+
+	lcdc->clk_per = devm_clk_get(dev, "per");
+	if (IS_ERR(lcdc->clk_per))
+		return dev_err_probe(dev, PTR_ERR(lcdc->clk_per), "Failed to get %s clk\n", "per");
+
+	ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32));
+	if (ret)
+		return dev_err_probe(dev, ret, "Cannot set DMA Mask\n");
+
+	/* Modeset init */
+	ret = drmm_mode_config_init(drm);
+	if (ret)
+		return dev_err_probe(dev, ret, "Cannot initialize mode configuration structure\n");
+
+	/* CRTC, Plane, Encoder */
+	ret = drm_simple_display_pipe_init(drm, &lcdc->pipe,
+					   &imx_lcdc_pipe_funcs,
+					   imx_lcdc_formats,
+					   ARRAY_SIZE(imx_lcdc_formats), NULL, NULL);
+	if (ret < 0)
+		return dev_err_probe(drm->dev, ret, "Cannot setup simple display pipe\n");
+
+	ret = drm_vblank_init(drm, drm->mode_config.num_crtc);
+	if (ret < 0)
+		return dev_err_probe(drm->dev, ret, "Failed to initialize vblank\n");
+
+	ret = drm_bridge_attach(&lcdc->pipe.encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+	if (ret)
+		return dev_err_probe(drm->dev, ret, "Cannot attach bridge\n");
+
+	lcdc->connector = drm_bridge_connector_init(drm, &lcdc->pipe.encoder);
+	if (IS_ERR(lcdc->connector))
+		return dev_err_probe(drm->dev, PTR_ERR(lcdc->connector), "Cannot init bridge connector\n");
+
+	drm_connector_attach_encoder(lcdc->connector, &lcdc->pipe.encoder);
+
+	/*
+	 * 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,
+	 * PER and AHB clock so that we force some kind of 'reset'
+	 * to the LCDC block.
+	 */
+
+	ret = clk_prepare_enable(lcdc->clk_ipg);
+	if (ret)
+		return dev_err_probe(dev, ret, "Cannot enable ipg clock\n");
+	clk_disable_unprepare(lcdc->clk_ipg);
+
+	ret = clk_prepare_enable(lcdc->clk_per);
+	if (ret)
+		return dev_err_probe(dev, ret, "Cannot enable per clock\n");
+	clk_disable_unprepare(lcdc->clk_per);
+
+	ret = clk_prepare_enable(lcdc->clk_ahb);
+	if (ret)
+		return dev_err_probe(dev, ret, "Cannot enable ahb clock\n");
+	clk_disable_unprepare(lcdc->clk_ahb);
+
+	drm->mode_config.min_width = LCDC_MIN_XRES;
+	drm->mode_config.max_width = LCDC_MAX_XRES;
+	drm->mode_config.min_height = LCDC_MIN_YRES;
+	drm->mode_config.max_height = LCDC_MAX_YRES;
+	drm->mode_config.preferred_depth = 16;
+	drm->mode_config.funcs = &imx_lcdc_mode_config_funcs;
+	drm->mode_config.helper_private = &imx_lcdc_mode_config_helpers;
+
+	drm_mode_config_reset(drm);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		ret = irq;
+		return ret;
+	}
+
+	ret = devm_request_irq(dev, irq, imx_lcdc_irq_handler, 0, "imx-lcdc", lcdc);
+	if (ret < 0)
+		return dev_err_probe(drm->dev, ret, "Failed to install IRQ handler\n");
+
+	platform_set_drvdata(pdev, drm);
+
+	ret = drm_dev_register(&lcdc->drm, 0);
+	if (ret)
+		return dev_err_probe(dev, ret, "Cannot register device\n");
+
+	drm_fbdev_generic_setup(drm, 0);
+
+	return 0;
+}
+
+static int imx_lcdc_remove(struct platform_device *pdev)
+{
+	struct drm_device *drm = platform_get_drvdata(pdev);
+
+	drm_dev_unregister(drm);
+	drm_atomic_helper_shutdown(drm);
+
+	return 0;
+}
+
+static void imx_lcdc_shutdown(struct platform_device *pdev)
+{
+	drm_atomic_helper_shutdown(platform_get_drvdata(pdev));
+}
+
+static struct platform_driver imx_lcdc_driver = {
+	.driver = {
+		.name = "imx-lcdc",
+		.of_match_table = imx_lcdc_of_dev_id,
+	},
+	.probe = imx_lcdc_probe,
+	.remove = imx_lcdc_remove,
+	.shutdown = imx_lcdc_shutdown,
+};
+module_platform_driver(imx_lcdc_driver);
+
+MODULE_AUTHOR("Marian Cichy <M.Cichy@pengutronix.de>");
+MODULE_DESCRIPTION("Freescale i.MX LCDC driver");
+MODULE_LICENSE("GPL");