drm: Add support of ARC PGU display controller

ARC PGU could be found on some development boards from Synopsys.
This is a simple byte streamer that reads data from a framebuffer
and sends data to the single encoder.
Signed-off-by: Carlos Palminha <palminha@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-snps-arc@lists.infradead.org

drivers/gpu/drm/Kconfig

@@ -281,3 +281,5 @@ source "drivers/gpu/drm/imx/Kconfig"
 source "drivers/gpu/drm/vc4/Kconfig"
 
 source "drivers/gpu/drm/etnaviv/Kconfig"
+
+source "drivers/gpu/drm/arc/Kconfig"

drivers/gpu/drm/Makefile

@@ -78,3 +78,4 @@ obj-y			+= panel/
 obj-y			+= bridge/
 obj-$(CONFIG_DRM_FSL_DCU) += fsl-dcu/
 obj-$(CONFIG_DRM_ETNAVIV) += etnaviv/
+obj-$(CONFIG_DRM_ARCPGU)+= arc/

drivers/gpu/drm/arc/Kconfig

+config DRM_ARCPGU
+	tristate "ARC PGU"
+	depends on DRM && OF
+	select DRM_KMS_CMA_HELPER
+	select DRM_KMS_FB_HELPER
+	select DRM_KMS_HELPER
+	help
+	  Choose this option if you have an ARC PGU controller.
+
+	  If M is selected the module will be called arcpgu.

drivers/gpu/drm/arc/Makefile

+arcpgu-y := arcpgu_crtc.o arcpgu_hdmi.o arcpgu_drv.o
+obj-$(CONFIG_DRM_ARCPGU) += arcpgu.o

drivers/gpu/drm/arc/arcpgu.h

+/*
+ * ARC PGU DRM driver.
+ *
+ * Copyright (C) 2016 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _ARCPGU_H_
+#define _ARCPGU_H_
+
+struct arcpgu_drm_private {
+	void __iomem		*regs;
+	struct clk		*clk;
+	struct drm_fbdev_cma	*fbdev;
+	struct drm_framebuffer	*fb;
+	struct list_head	event_list;
+	struct drm_crtc		crtc;
+	struct drm_plane	*plane;
+};
+
+#define crtc_to_arcpgu_priv(x) container_of(x, struct arcpgu_drm_private, crtc)
+
+static inline void arc_pgu_write(struct arcpgu_drm_private *arcpgu,
+				 unsigned int reg, u32 value)
+{
+	iowrite32(value, arcpgu->regs + reg);
+}
+
+static inline u32 arc_pgu_read(struct arcpgu_drm_private *arcpgu,
+			       unsigned int reg)
+{
+	return ioread32(arcpgu->regs + reg);
+}
+
+int arc_pgu_setup_crtc(struct drm_device *dev);
+int arcpgu_drm_hdmi_init(struct drm_device *drm, struct device_node *np);
+struct drm_fbdev_cma *arcpgu_fbdev_cma_init(struct drm_device *dev,
+	unsigned int preferred_bpp, unsigned int num_crtc,
+	unsigned int max_conn_count);
+
+#endif

drivers/gpu/drm/arc/arcpgu_crtc.c

+/*
+ * ARC PGU DRM driver.
+ *
+ * Copyright (C) 2016 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_fb_cma_helper.h>
+#include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_plane_helper.h>
+#include <linux/clk.h>
+#include <linux/platform_data/simplefb.h>
+
+#include "arcpgu.h"
+#include "arcpgu_regs.h"
+
+#define ENCODE_PGU_XY(x, y)	((((x) - 1) << 16) | ((y) - 1))
+
+static struct simplefb_format supported_formats[] = {
+	{ "r5g6b5", 16, {11, 5}, {5, 6}, {0, 5}, {0, 0}, DRM_FORMAT_RGB565 },
+	{ "r8g8b8", 24, {16, 8}, {8, 8}, {0, 8}, {0, 0}, DRM_FORMAT_RGB888 },
+};
+
+static void arc_pgu_set_pxl_fmt(struct drm_crtc *crtc)
+{
+	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
+	uint32_t pixel_format = crtc->primary->state->fb->pixel_format;
+	struct simplefb_format *format = NULL;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(supported_formats); i++) {
+		if (supported_formats[i].fourcc == pixel_format)
+			format = &supported_formats[i];
+	}
+
+	if (WARN_ON(!format))
+		return;
+
+	if (format->fourcc == DRM_FORMAT_RGB888)
+		arc_pgu_write(arcpgu, ARCPGU_REG_CTRL,
+			      arc_pgu_read(arcpgu, ARCPGU_REG_CTRL) |
+					   ARCPGU_MODE_RGB888_MASK);
+
+}
+
+static const struct drm_crtc_funcs arc_pgu_crtc_funcs = {
+	.destroy = drm_crtc_cleanup,
+	.set_config = drm_atomic_helper_set_config,
+	.page_flip = drm_atomic_helper_page_flip,
+	.reset = drm_atomic_helper_crtc_reset,
+	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
+};
+
+static void arc_pgu_crtc_mode_set_nofb(struct drm_crtc *crtc)
+{
+	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
+	struct drm_display_mode *m = &crtc->state->adjusted_mode;
+	u32 val;
+
+	arc_pgu_write(arcpgu, ARCPGU_REG_FMT,
+		      ENCODE_PGU_XY(m->crtc_htotal, m->crtc_vtotal));
+
+	arc_pgu_write(arcpgu, ARCPGU_REG_HSYNC,
+		      ENCODE_PGU_XY(m->crtc_hsync_start - m->crtc_hdisplay,
+				    m->crtc_hsync_end - m->crtc_hdisplay));
+
+	arc_pgu_write(arcpgu, ARCPGU_REG_VSYNC,
+		      ENCODE_PGU_XY(m->crtc_vsync_start - m->crtc_vdisplay,
+				    m->crtc_vsync_end - m->crtc_vdisplay));
+
+	arc_pgu_write(arcpgu, ARCPGU_REG_ACTIVE,
+		      ENCODE_PGU_XY(m->crtc_hblank_end - m->crtc_hblank_start,
+				    m->crtc_vblank_end - m->crtc_vblank_start));
+
+	val = arc_pgu_read(arcpgu, ARCPGU_REG_CTRL);
+
+	if (m->flags & DRM_MODE_FLAG_PVSYNC)
+		val |= ARCPGU_CTRL_VS_POL_MASK << ARCPGU_CTRL_VS_POL_OFST;
+	else
+		val &= ~(ARCPGU_CTRL_VS_POL_MASK << ARCPGU_CTRL_VS_POL_OFST);
+
+	if (m->flags & DRM_MODE_FLAG_PHSYNC)
+		val |= ARCPGU_CTRL_HS_POL_MASK << ARCPGU_CTRL_HS_POL_OFST;
+	else
+		val &= ~(ARCPGU_CTRL_HS_POL_MASK << ARCPGU_CTRL_HS_POL_OFST);
+
+	arc_pgu_write(arcpgu, ARCPGU_REG_CTRL, val);
+	arc_pgu_write(arcpgu, ARCPGU_REG_STRIDE, 0);
+	arc_pgu_write(arcpgu, ARCPGU_REG_START_SET, 1);
+
+	arc_pgu_set_pxl_fmt(crtc);
+
+	clk_set_rate(arcpgu->clk, m->crtc_clock * 1000);
+}
+
+static void arc_pgu_crtc_enable(struct drm_crtc *crtc)
+{
+	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
+
+	clk_prepare_enable(arcpgu->clk);
+	arc_pgu_write(arcpgu, ARCPGU_REG_CTRL,
+		      arc_pgu_read(arcpgu, ARCPGU_REG_CTRL) |
+		      ARCPGU_CTRL_ENABLE_MASK);
+}
+
+static void arc_pgu_crtc_disable(struct drm_crtc *crtc)
+{
+	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
+
+	if (!crtc->primary->fb)
+		return;
+
+	clk_disable_unprepare(arcpgu->clk);
+	arc_pgu_write(arcpgu, ARCPGU_REG_CTRL,
+			      arc_pgu_read(arcpgu, ARCPGU_REG_CTRL) &
+			      ~ARCPGU_CTRL_ENABLE_MASK);
+}
+
+static int arc_pgu_crtc_atomic_check(struct drm_crtc *crtc,
+				     struct drm_crtc_state *state)
+{
+	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
+	struct drm_display_mode *mode = &state->adjusted_mode;
+	long rate, clk_rate = mode->clock * 1000;
+
+	rate = clk_round_rate(arcpgu->clk, clk_rate);
+	if (rate != clk_rate)
+		return -EINVAL;
+
+	return 0;
+}
+
+static void arc_pgu_crtc_atomic_begin(struct drm_crtc *crtc,
+				      struct drm_crtc_state *state)
+{
+	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
+	unsigned long flags;
+
+	if (crtc->state->event) {
+		struct drm_pending_vblank_event *event = crtc->state->event;
+
+		crtc->state->event = NULL;
+		event->pipe = drm_crtc_index(crtc);
+
+		WARN_ON(drm_crtc_vblank_get(crtc) != 0);
+
+		spin_lock_irqsave(&crtc->dev->event_lock, flags);
+		list_add_tail(&event->base.link, &arcpgu->event_list);
+		spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
+	}
+}
+
+static const struct drm_crtc_helper_funcs arc_pgu_crtc_helper_funcs = {
+	.mode_set	= drm_helper_crtc_mode_set,
+	.mode_set_base	= drm_helper_crtc_mode_set_base,
+	.mode_set_nofb	= arc_pgu_crtc_mode_set_nofb,
+	.enable		= arc_pgu_crtc_enable,
+	.disable	= arc_pgu_crtc_disable,
+	.prepare	= arc_pgu_crtc_disable,
+	.commit		= arc_pgu_crtc_enable,
+	.atomic_check	= arc_pgu_crtc_atomic_check,
+	.atomic_begin	= arc_pgu_crtc_atomic_begin,
+};
+
+static void arc_pgu_plane_atomic_update(struct drm_plane *plane,
+					struct drm_plane_state *state)
+{
+	struct arcpgu_drm_private *arcpgu;
+	struct drm_gem_cma_object *gem;
+
+	if (!plane->state->crtc || !plane->state->fb)
+		return;
+
+	arcpgu = crtc_to_arcpgu_priv(plane->state->crtc);
+	gem = drm_fb_cma_get_gem_obj(plane->state->fb, 0);
+	arc_pgu_write(arcpgu, ARCPGU_REG_BUF0_ADDR, gem->paddr);
+}
+
+static const struct drm_plane_helper_funcs arc_pgu_plane_helper_funcs = {
+	.prepare_fb = NULL,
+	.cleanup_fb = NULL,
+	.atomic_update = arc_pgu_plane_atomic_update,
+};
+
+static void arc_pgu_plane_destroy(struct drm_plane *plane)
+{
+	drm_plane_helper_disable(plane);
+	drm_plane_cleanup(plane);
+}
+
+static const struct drm_plane_funcs arc_pgu_plane_funcs = {
+	.update_plane		= drm_atomic_helper_update_plane,
+	.disable_plane		= drm_atomic_helper_disable_plane,
+	.destroy		= arc_pgu_plane_destroy,
+	.reset			= drm_atomic_helper_plane_reset,
+	.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
+	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
+};
+
+static struct drm_plane *arc_pgu_plane_init(struct drm_device *drm)
+{
+	struct arcpgu_drm_private *arcpgu = drm->dev_private;
+	struct drm_plane *plane = NULL;
+	u32 formats[ARRAY_SIZE(supported_formats)], i;
+	int ret;
+
+	plane = devm_kzalloc(drm->dev, sizeof(*plane), GFP_KERNEL);
+	if (!plane)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < ARRAY_SIZE(supported_formats); i++)
+		formats[i] = supported_formats[i].fourcc;
+
+	ret = drm_universal_plane_init(drm, plane, 0xff, &arc_pgu_plane_funcs,
+				       formats, ARRAY_SIZE(formats),
+				       DRM_PLANE_TYPE_PRIMARY, NULL);
+	if (ret)
+		return ERR_PTR(ret);
+
+	drm_plane_helper_add(plane, &arc_pgu_plane_helper_funcs);
+	arcpgu->plane = plane;
+
+	return plane;
+}
+
+int arc_pgu_setup_crtc(struct drm_device *drm)
+{
+	struct arcpgu_drm_private *arcpgu = drm->dev_private;
+	struct drm_plane *primary;
+	int ret;
+
+	primary = arc_pgu_plane_init(drm);
+	if (IS_ERR(primary))
+		return PTR_ERR(primary);
+
+	ret = drm_crtc_init_with_planes(drm, &arcpgu->crtc, primary, NULL,
+					&arc_pgu_crtc_funcs, NULL);
+	if (ret) {
+		arc_pgu_plane_destroy(primary);
+		return ret;
+	}
+
+	drm_crtc_helper_add(&arcpgu->crtc, &arc_pgu_crtc_helper_funcs);
+	return 0;
+}

drivers/gpu/drm/arc/arcpgu_drv.c

+/*
+ * ARC PGU DRM driver.
+ *
+ * Copyright (C) 2016 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/clk.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_fb_cma_helper.h>
+#include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_atomic_helper.h>
+
+#include "arcpgu.h"
+#include "arcpgu_regs.h"
+
+static void arcpgu_fb_output_poll_changed(struct drm_device *dev)
+{
+	struct arcpgu_drm_private *arcpgu = dev->dev_private;
+
+	if (arcpgu->fbdev)
+		drm_fbdev_cma_hotplug_event(arcpgu->fbdev);
+}
+
+static int arcpgu_atomic_commit(struct drm_device *dev,
+				    struct drm_atomic_state *state, bool async)
+{
+	return drm_atomic_helper_commit(dev, state, false);
+}
+
+static struct drm_mode_config_funcs arcpgu_drm_modecfg_funcs = {
+	.fb_create  = drm_fb_cma_create,
+	.output_poll_changed = arcpgu_fb_output_poll_changed,
+	.atomic_check = drm_atomic_helper_check,
+	.atomic_commit = arcpgu_atomic_commit,
+};
+
+static void arcpgu_setup_mode_config(struct drm_device *drm)
+{
+	drm_mode_config_init(drm);
+	drm->mode_config.min_width = 0;
+	drm->mode_config.min_height = 0;
+	drm->mode_config.max_width = 1920;
+	drm->mode_config.max_height = 1080;
+	drm->mode_config.funcs = &arcpgu_drm_modecfg_funcs;
+}
+
+int arcpgu_gem_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	int ret;
+
+	ret = drm_gem_mmap(filp, vma);
+	if (ret)
+		return ret;
+
+	vma->vm_page_prot = pgprot_noncached(vm_get_page_prot(vma->vm_flags));
+	return 0;
+}
+
+static const struct file_operations arcpgu_drm_ops = {
+	.owner = THIS_MODULE,
+	.open = drm_open,
+	.release = drm_release,
+	.unlocked_ioctl = drm_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = drm_compat_ioctl,
+#endif
+	.poll = drm_poll,
+	.read = drm_read,
+	.llseek = no_llseek,
+	.mmap = arcpgu_gem_mmap,
+};
+
+static void arcpgu_preclose(struct drm_device *drm, struct drm_file *file)
+{
+	struct arcpgu_drm_private *arcpgu = drm->dev_private;
+	struct drm_pending_vblank_event *e, *t;
+	unsigned long flags;
+
+	spin_lock_irqsave(&drm->event_lock, flags);
+	list_for_each_entry_safe(e, t, &arcpgu->event_list, base.link) {
+		if (e->base.file_priv != file)
+			continue;
+		list_del(&e->base.link);
+		e->base.destroy(&e->base);
+	}
+	spin_unlock_irqrestore(&drm->event_lock, flags);
+}
+
+static void arcpgu_lastclose(struct drm_device *drm)
+{
+	struct arcpgu_drm_private *arcpgu = drm->dev_private;
+
+	drm_fbdev_cma_restore_mode(arcpgu->fbdev);
+}
+
+static int arcpgu_load(struct drm_device *drm)
+{
+	struct platform_device *pdev = to_platform_device(drm->dev);
+	struct arcpgu_drm_private *arcpgu;
+	struct device_node *encoder_node;
+	struct resource *res;
+	int ret;
+
+	arcpgu = devm_kzalloc(&pdev->dev, sizeof(*arcpgu), GFP_KERNEL);
+	if (arcpgu == NULL)
+		return -ENOMEM;
+
+	drm->dev_private = arcpgu;
+
+	arcpgu->clk = devm_clk_get(drm->dev, "pxlclk");
+	if (IS_ERR(arcpgu->clk))
+		return PTR_ERR(arcpgu->clk);
+
+	INIT_LIST_HEAD(&arcpgu->event_list);
+
+	arcpgu_setup_mode_config(drm);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	arcpgu->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(arcpgu->regs)) {
+		dev_err(drm->dev, "Could not remap IO mem\n");
+		return PTR_ERR(arcpgu->regs);
+	}
+
+	dev_info(drm->dev, "arc_pgu ID: 0x%x\n",
+		 arc_pgu_read(arcpgu, ARCPGU_REG_ID));
+
+	if (dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32)))
+		return -ENODEV;
+
+	if (arc_pgu_setup_crtc(drm) < 0)
+		return -ENODEV;
+
+	/* find the encoder node and initialize it */
+	encoder_node = of_parse_phandle(drm->dev->of_node, "encoder-slave", 0);
+	if (!encoder_node) {
+		dev_err(drm->dev, "failed to get an encoder slave node\n");
+		return -ENODEV;
+	}
+
+	ret = arcpgu_drm_hdmi_init(drm, encoder_node);
+	if (ret < 0)
+		return ret;
+
+	drm_mode_config_reset(drm);
+	drm_kms_helper_poll_init(drm);
+
+	arcpgu->fbdev = drm_fbdev_cma_init(drm, 16,
+					      drm->mode_config.num_crtc,
+					      drm->mode_config.num_connector);
+	if (IS_ERR(arcpgu->fbdev)) {
+		ret = PTR_ERR(arcpgu->fbdev);
+		arcpgu->fbdev = NULL;
+		return -ENODEV;
+	}
+
+	platform_set_drvdata(pdev, arcpgu);
+	return 0;
+}
+
+int arcpgu_unload(struct drm_device *drm)
+{
+	struct arcpgu_drm_private *arcpgu = drm->dev_private;
+
+	if (arcpgu->fbdev) {
+		drm_fbdev_cma_fini(arcpgu->fbdev);
+		arcpgu->fbdev = NULL;
+	}
+	drm_kms_helper_poll_fini(drm);
+	drm_vblank_cleanup(drm);
+	drm_mode_config_cleanup(drm);
+
+	return 0;
+}
+
+static struct drm_driver arcpgu_drm_driver = {
+	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_PRIME |
+			   DRIVER_ATOMIC,
+	.preclose = arcpgu_preclose,
+	.lastclose = arcpgu_lastclose,
+	.name = "drm-arcpgu",
+	.desc = "ARC PGU Controller",
+	.date = "20160219",
+	.major = 1,
+	.minor = 0,
+	.patchlevel = 0,
+	.fops = &arcpgu_drm_ops,
+	.dumb_create = drm_gem_cma_dumb_create,
+	.dumb_map_offset = drm_gem_cma_dumb_map_offset,
+	.dumb_destroy = drm_gem_dumb_destroy,
+	.get_vblank_counter = drm_vblank_no_hw_counter,
+	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
+	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
+	.gem_free_object = drm_gem_cma_free_object,
+	.gem_vm_ops = &drm_gem_cma_vm_ops,
+	.gem_prime_export = drm_gem_prime_export,
+	.gem_prime_import = drm_gem_prime_import,
+	.gem_prime_get_sg_table = drm_gem_cma_prime_get_sg_table,
+	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
+	.gem_prime_vmap = drm_gem_cma_prime_vmap,
+	.gem_prime_vunmap = drm_gem_cma_prime_vunmap,
+	.gem_prime_mmap = drm_gem_cma_prime_mmap,
+};
+
+static int arcpgu_probe(struct platform_device *pdev)
+{
+	struct drm_device *drm;
+	int ret;
+
+	drm = drm_dev_alloc(&arcpgu_drm_driver, &pdev->dev);
+	if (!drm)
+		return -ENOMEM;
+
+	ret = arcpgu_load(drm);
+	if (ret)
+		goto err_unref;
+
+	ret = drm_dev_register(drm, 0);
+	if (ret)
+		goto err_unload;
+
+	ret = drm_connector_register_all(drm);
+	if (ret)
+		goto err_unregister;
+
+	return 0;
+
+err_unregister:
+	drm_dev_unregister(drm);
+
+err_unload:
+	arcpgu_unload(drm);
+
+err_unref:
+	drm_dev_unref(drm);
+
+	return ret;
+}
+
+static int arcpgu_remove(struct platform_device *pdev)
+{
+	struct drm_device *drm = platform_get_drvdata(pdev);
+
+	drm_connector_unregister_all(drm);
+	drm_dev_unregister(drm);
+	arcpgu_unload(drm);
+	drm_dev_unref(drm);
+
+	return 0;
+}
+
+static const struct of_device_id arcpgu_of_table[] = {
+	{.compatible = "snps,arcpgu"},
+	{}
+};
+
+MODULE_DEVICE_TABLE(of, arcpgu_of_table);
+
+static struct platform_driver arcpgu_platform_driver = {
+	.probe = arcpgu_probe,
+	.remove = arcpgu_remove,
+	.driver = {
+		   .name = "arcpgu",
+		   .of_match_table = arcpgu_of_table,
+		   },
+};
+
+module_platform_driver(arcpgu_platform_driver);
+
+MODULE_AUTHOR("Carlos Palminha <palminha@synopsys.com>");
+MODULE_DESCRIPTION("ARC PGU DRM driver");
+MODULE_LICENSE("GPL");

drivers/gpu/drm/arc/arcpgu_hdmi.c

+/*
+ * ARC PGU DRM driver.
+ *
+ * Copyright (C) 2016 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_encoder_slave.h>
+#include <drm/drm_atomic_helper.h>
+
+#include "arcpgu.h"
+
+struct arcpgu_drm_connector {
+	struct drm_connector connector;
+	struct drm_encoder_slave *encoder_slave;
+};
+
+static int arcpgu_drm_connector_get_modes(struct drm_connector *connector)
+{
+	const struct drm_encoder_slave_funcs *sfuncs;
+	struct drm_encoder_slave *slave;
+	struct arcpgu_drm_connector *con =
+		container_of(connector, struct arcpgu_drm_connector, connector);
+
+	slave = con->encoder_slave;
+	if (slave == NULL) {
+		dev_err(connector->dev->dev,
+			"connector_get_modes: cannot find slave encoder for connector\n");
+		return 0;
+	}
+
+	sfuncs = slave->slave_funcs;
+	if (sfuncs->get_modes == NULL)
+		return 0;
+
+	return sfuncs->get_modes(&slave->base, connector);
+}
+
+struct drm_encoder *
+arcpgu_drm_connector_best_encoder(struct drm_connector *connector)
+{
+	struct drm_encoder_slave *slave;
+	struct arcpgu_drm_connector *con =
+		container_of(connector, struct arcpgu_drm_connector, connector);
+
+	slave = con->encoder_slave;
+	if (slave == NULL) {
+		dev_err(connector->dev->dev,
+			"connector_best_encoder: cannot find slave encoder for connector\n");
+		return NULL;
+	}
+
+	return &slave->base;
+}
+
+static enum drm_connector_status
+arcpgu_drm_connector_detect(struct drm_connector *connector, bool force)
+{
+	enum drm_connector_status status = connector_status_unknown;
+	const struct drm_encoder_slave_funcs *sfuncs;
+	struct drm_encoder_slave *slave;
+
+	struct arcpgu_drm_connector *con =
+		container_of(connector, struct arcpgu_drm_connector, connector);
+
+	slave = con->encoder_slave;
+	if (slave == NULL) {
+		dev_err(connector->dev->dev,
+			"connector_detect: cannot find slave encoder for connector\n");
+		return status;
+	}
+
+	sfuncs = slave->slave_funcs;
+	if (sfuncs && sfuncs->detect)
+		return sfuncs->detect(&slave->base, connector);
+
+	dev_err(connector->dev->dev, "connector_detect: could not detect slave funcs\n");
+	return status;
+}
+
+static void arcpgu_drm_connector_destroy(struct drm_connector *connector)
+{
+	drm_connector_unregister(connector);
+	drm_connector_cleanup(connector);
+}
+
+static const struct drm_connector_helper_funcs
+arcpgu_drm_connector_helper_funcs = {
+	.get_modes = arcpgu_drm_connector_get_modes,
+	.best_encoder = arcpgu_drm_connector_best_encoder,
+};
+
+static const struct drm_connector_funcs arcpgu_drm_connector_funcs = {
+	.dpms = drm_helper_connector_dpms,
+	.reset = drm_atomic_helper_connector_reset,
+	.detect = arcpgu_drm_connector_detect,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.destroy = arcpgu_drm_connector_destroy,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static struct drm_encoder_helper_funcs arcpgu_drm_encoder_helper_funcs = {
+	.dpms = drm_i2c_encoder_dpms,
+	.mode_fixup = drm_i2c_encoder_mode_fixup,
+	.mode_set = drm_i2c_encoder_mode_set,
+	.prepare = drm_i2c_encoder_prepare,
+	.commit = drm_i2c_encoder_commit,
+	.detect = drm_i2c_encoder_detect,
+};
+
+static struct drm_encoder_funcs arcpgu_drm_encoder_funcs = {
+	.destroy = drm_encoder_cleanup,
+};
+
+int arcpgu_drm_hdmi_init(struct drm_device *drm, struct device_node *np)
+{
+	struct arcpgu_drm_connector *arcpgu_connector;
+	struct drm_i2c_encoder_driver *driver;
+	struct drm_encoder_slave *encoder;
+	struct drm_connector *connector;
+	struct i2c_client *i2c_slave;
+	int ret;
+
+	encoder = devm_kzalloc(drm->dev, sizeof(*encoder), GFP_KERNEL);
+	if (encoder == NULL)
+		return -ENOMEM;
+
+	i2c_slave = of_find_i2c_device_by_node(np);
+	if (!i2c_slave || !i2c_get_clientdata(i2c_slave)) {
+		dev_err(drm->dev, "failed to find i2c slave encoder\n");
+		return -EPROBE_DEFER;
+	}
+
+	if (i2c_slave->dev.driver == NULL) {
+		dev_err(drm->dev, "failed to find i2c slave driver\n");
+		return -EPROBE_DEFER;
+	}
+
+	driver =
+	    to_drm_i2c_encoder_driver(to_i2c_driver(i2c_slave->dev.driver));
+	ret = driver->encoder_init(i2c_slave, drm, encoder);
+	if (ret) {
+		dev_err(drm->dev, "failed to initialize i2c encoder slave\n");
+		return ret;
+	}
+
+	encoder->base.possible_crtcs = 1;
+	encoder->base.possible_clones = 0;
+	ret = drm_encoder_init(drm, &encoder->base, &arcpgu_drm_encoder_funcs,
+			       DRM_MODE_ENCODER_TMDS, NULL);
+	if (ret)
+		return ret;
+
+	drm_encoder_helper_add(&encoder->base,
+			       &arcpgu_drm_encoder_helper_funcs);
+
+	arcpgu_connector = devm_kzalloc(drm->dev, sizeof(*arcpgu_connector),
+					GFP_KERNEL);
+	if (!arcpgu_connector) {
+		ret = -ENOMEM;
+		goto error_encoder_cleanup;
+	}
+
+	connector = &arcpgu_connector->connector;
+	drm_connector_helper_add(connector, &arcpgu_drm_connector_helper_funcs);
+	ret = drm_connector_init(drm, connector, &arcpgu_drm_connector_funcs,
+			DRM_MODE_CONNECTOR_HDMIA);
+	if (ret < 0) {
+		dev_err(drm->dev, "failed to initialize drm connector\n");
+		goto error_encoder_cleanup;
+	}
+
+	ret = drm_mode_connector_attach_encoder(connector, &encoder->base);
+	if (ret < 0) {
+		dev_err(drm->dev, "could not attach connector to encoder\n");
+		drm_connector_unregister(connector);
+		goto error_connector_cleanup;
+	}
+
+	arcpgu_connector->encoder_slave = encoder;
+
+	return 0;
+
+error_connector_cleanup:
+	drm_connector_cleanup(connector);
+
+error_encoder_cleanup:
+	drm_encoder_cleanup(&encoder->base);
+	return ret;
+}

drivers/gpu/drm/arc/arcpgu_regs.h

+/*
+ * ARC PGU DRM driver.
+ *
+ * Copyright (C) 2016 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _ARC_PGU_REGS_H_
+#define _ARC_PGU_REGS_H_
+
+#define ARCPGU_REG_CTRL		0x00
+#define ARCPGU_REG_STAT		0x04
+#define ARCPGU_REG_FMT		0x10
+#define ARCPGU_REG_HSYNC	0x14
+#define ARCPGU_REG_VSYNC	0x18
+#define ARCPGU_REG_ACTIVE	0x1c
+#define ARCPGU_REG_BUF0_ADDR	0x40
+#define ARCPGU_REG_STRIDE	0x50
+#define ARCPGU_REG_START_SET	0x84
+
+#define ARCPGU_REG_ID		0x3FC
+
+#define ARCPGU_CTRL_ENABLE_MASK	0x02
+#define ARCPGU_CTRL_VS_POL_MASK	0x1
+#define ARCPGU_CTRL_VS_POL_OFST	0x3
+#define ARCPGU_CTRL_HS_POL_MASK	0x1
+#define ARCPGU_CTRL_HS_POL_OFST	0x4
+#define ARCPGU_MODE_RGB888_MASK	0x04
+#define ARCPGU_STAT_BUSY_MASK	0x02
+
+#endif