tilcdc_drv.c

/*
 * Copyright (C) 2012 Texas Instruments
 * Author: Rob Clark <robdclark@gmail.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.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/* LCDC DRM driver, based on da8xx-fb */

#include <linux/component.h>
#include <linux/pinctrl/consumer.h>
#include <linux/suspend.h>
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>

#include "tilcdc_drv.h"
#include "tilcdc_regs.h"
#include "tilcdc_tfp410.h"
#include "tilcdc_panel.h"
#include "tilcdc_external.h"

#include "drm_fb_helper.h"

static LIST_HEAD(module_list);

void tilcdc_module_init(struct tilcdc_module *mod, const char *name,
		const struct tilcdc_module_ops *funcs)
{
	mod->name = name;
	mod->funcs = funcs;
	INIT_LIST_HEAD(&mod->list);
	list_add(&mod->list, &module_list);
}

void tilcdc_module_cleanup(struct tilcdc_module *mod)
{
	list_del(&mod->list);
}

static struct of_device_id tilcdc_of_match[];

static struct drm_framebuffer *tilcdc_fb_create(struct drm_device *dev,
		struct drm_file *file_priv, const struct drm_mode_fb_cmd2 *mode_cmd)
{
	return drm_fb_cma_create(dev, file_priv, mode_cmd);
}

static void tilcdc_fb_output_poll_changed(struct drm_device *dev)
{
	struct tilcdc_drm_private *priv = dev->dev_private;
	drm_fbdev_cma_hotplug_event(priv->fbdev);
}

int tilcdc_atomic_check(struct drm_device *dev,
			struct drm_atomic_state *state)
{
	int ret;

	ret = drm_atomic_helper_check_modeset(dev, state);
	if (ret)
		return ret;

	ret = drm_atomic_helper_check_planes(dev, state);
	if (ret)
		return ret;

	/*
	 * tilcdc ->atomic_check can update ->mode_changed if pixel format
	 * changes, hence will we check modeset changes again.
	 */
	ret = drm_atomic_helper_check_modeset(dev, state);
	if (ret)
		return ret;

	return ret;
}

static int tilcdc_commit(struct drm_device *dev,
		  struct drm_atomic_state *state,
		  bool async)
{
	int ret;

	ret = drm_atomic_helper_prepare_planes(dev, state);
	if (ret)
		return ret;

	drm_atomic_helper_swap_state(state, true);

	/*
	 * Everything below can be run asynchronously without the need to grab
	 * any modeset locks at all under one condition: It must be guaranteed
	 * that the asynchronous work has either been cancelled (if the driver
	 * supports it, which at least requires that the framebuffers get
	 * cleaned up with drm_atomic_helper_cleanup_planes()) or completed
	 * before the new state gets committed on the software side with
	 * drm_atomic_helper_swap_state().
	 *
	 * This scheme allows new atomic state updates to be prepared and
	 * checked in parallel to the asynchronous completion of the previous
	 * update. Which is important since compositors need to figure out the
	 * composition of the next frame right after having submitted the
	 * current layout.
	 */

	drm_atomic_helper_commit_modeset_disables(dev, state);

	drm_atomic_helper_commit_planes(dev, state, false);

	drm_atomic_helper_commit_modeset_enables(dev, state);

	drm_atomic_helper_wait_for_vblanks(dev, state);

	drm_atomic_helper_cleanup_planes(dev, state);

	drm_atomic_state_free(state);

	return 0;
}

static const struct drm_mode_config_funcs mode_config_funcs = {
	.fb_create = tilcdc_fb_create,
	.output_poll_changed = tilcdc_fb_output_poll_changed,
	.atomic_check = tilcdc_atomic_check,
	.atomic_commit = tilcdc_commit,
};

static int modeset_init(struct drm_device *dev)
{
	struct tilcdc_drm_private *priv = dev->dev_private;
	struct tilcdc_module *mod;

	drm_mode_config_init(dev);

	priv->crtc = tilcdc_crtc_create(dev);

	list_for_each_entry(mod, &module_list, list) {
		DBG("loading module: %s", mod->name);
		mod->funcs->modeset_init(mod, dev);
	}

	dev->mode_config.min_width = 0;
	dev->mode_config.min_height = 0;
	dev->mode_config.max_width = tilcdc_crtc_max_width(priv->crtc);
	dev->mode_config.max_height = 2048;
	dev->mode_config.funcs = &mode_config_funcs;

	return 0;
}

#ifdef CONFIG_CPU_FREQ
static int cpufreq_transition(struct notifier_block *nb,
				     unsigned long val, void *data)
{
	struct tilcdc_drm_private *priv = container_of(nb,
			struct tilcdc_drm_private, freq_transition);
	if (val == CPUFREQ_POSTCHANGE) {
		if (priv->lcd_fck_rate != clk_get_rate(priv->clk)) {
			priv->lcd_fck_rate = clk_get_rate(priv->clk);
			tilcdc_crtc_update_clk(priv->crtc);
		}
	}

	return 0;
}
#endif

/*
 * DRM operations:
 */

static int tilcdc_unload(struct drm_device *dev)
{
	struct tilcdc_drm_private *priv = dev->dev_private;

	tilcdc_crtc_dpms(priv->crtc, DRM_MODE_DPMS_OFF);

	tilcdc_remove_external_encoders(dev);

	drm_fbdev_cma_fini(priv->fbdev);
	drm_kms_helper_poll_fini(dev);
	drm_mode_config_cleanup(dev);
	drm_vblank_cleanup(dev);

	pm_runtime_get_sync(dev->dev);
	drm_irq_uninstall(dev);
	pm_runtime_put_sync(dev->dev);

#ifdef CONFIG_CPU_FREQ
	cpufreq_unregister_notifier(&priv->freq_transition,
			CPUFREQ_TRANSITION_NOTIFIER);
#endif

	if (priv->clk)
		clk_put(priv->clk);

	if (priv->mmio)
		iounmap(priv->mmio);

	flush_workqueue(priv->wq);
	destroy_workqueue(priv->wq);

	dev->dev_private = NULL;

	pm_runtime_disable(dev->dev);

	return 0;
}

static size_t tilcdc_num_regs(void);

static int tilcdc_load(struct drm_device *dev, unsigned long flags)
{
	struct platform_device *pdev = dev->platformdev;
	struct device_node *node = pdev->dev.of_node;
	struct tilcdc_drm_private *priv;
	struct tilcdc_module *mod;
	struct resource *res;
	u32 bpp = 0;
	int ret;

	priv = devm_kzalloc(dev->dev, sizeof(*priv), GFP_KERNEL);
	if (priv)
		priv->saved_register =
			devm_kcalloc(dev->dev, tilcdc_num_regs(),
				     sizeof(*priv->saved_register), GFP_KERNEL);
	if (!priv || !priv->saved_register) {
		dev_err(dev->dev, "failed to allocate private data\n");
		return -ENOMEM;
	}

	dev->dev_private = priv;

	priv->is_componentized =
		tilcdc_get_external_components(dev->dev, NULL) > 0;

	priv->wq = alloc_ordered_workqueue("tilcdc", 0);
	if (!priv->wq) {
		ret = -ENOMEM;
		goto fail_unset_priv;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(dev->dev, "failed to get memory resource\n");
		ret = -EINVAL;
		goto fail_free_wq;
	}

	priv->mmio = ioremap_nocache(res->start, resource_size(res));
	if (!priv->mmio) {
		dev_err(dev->dev, "failed to ioremap\n");
		ret = -ENOMEM;
		goto fail_free_wq;
	}

	priv->clk = clk_get(dev->dev, "fck");
	if (IS_ERR(priv->clk)) {
		dev_err(dev->dev, "failed to get functional clock\n");
		ret = -ENODEV;
		goto fail_iounmap;
	}

#ifdef CONFIG_CPU_FREQ
	priv->lcd_fck_rate = clk_get_rate(priv->clk);
	priv->freq_transition.notifier_call = cpufreq_transition;
	ret = cpufreq_register_notifier(&priv->freq_transition,
			CPUFREQ_TRANSITION_NOTIFIER);
	if (ret) {
		dev_err(dev->dev, "failed to register cpufreq notifier\n");
		goto fail_put_clk;
	}
#endif

	if (of_property_read_u32(node, "max-bandwidth", &priv->max_bandwidth))
		priv->max_bandwidth = TILCDC_DEFAULT_MAX_BANDWIDTH;

	DBG("Maximum Bandwidth Value %d", priv->max_bandwidth);

	if (of_property_read_u32(node, "ti,max-width", &priv->max_width))
		priv->max_width = TILCDC_DEFAULT_MAX_WIDTH;

	DBG("Maximum Horizontal Pixel Width Value %dpixels", priv->max_width);

	if (of_property_read_u32(node, "ti,max-pixelclock",
					&priv->max_pixelclock))
		priv->max_pixelclock = TILCDC_DEFAULT_MAX_PIXELCLOCK;

	DBG("Maximum Pixel Clock Value %dKHz", priv->max_pixelclock);

	pm_runtime_enable(dev->dev);

	/* Determine LCD IP Version */
	pm_runtime_get_sync(dev->dev);
	switch (tilcdc_read(dev, LCDC_PID_REG)) {
	case 0x4c100102:
		priv->rev = 1;
		break;
	case 0x4f200800:
	case 0x4f201000:
		priv->rev = 2;
		break;
	default:
		dev_warn(dev->dev, "Unknown PID Reg value 0x%08x, "
				"defaulting to LCD revision 1\n",
				tilcdc_read(dev, LCDC_PID_REG));
		priv->rev = 1;
		break;
	}

	pm_runtime_put_sync(dev->dev);

	ret = modeset_init(dev);
	if (ret < 0) {
		dev_err(dev->dev, "failed to initialize mode setting\n");
		goto fail_cpufreq_unregister;
	}

	platform_set_drvdata(pdev, dev);

	if (priv->is_componentized) {
		ret = component_bind_all(dev->dev, dev);
		if (ret < 0)
			goto fail_mode_config_cleanup;

		ret = tilcdc_add_external_encoders(dev, &bpp);
		if (ret < 0)
			goto fail_component_cleanup;
	}

	if ((priv->num_encoders == 0) || (priv->num_connectors == 0)) {
		dev_err(dev->dev, "no encoders/connectors found\n");
		ret = -ENXIO;
		goto fail_external_cleanup;
	}

	ret = drm_vblank_init(dev, 1);
	if (ret < 0) {
		dev_err(dev->dev, "failed to initialize vblank\n");
		goto fail_external_cleanup;
	}

	pm_runtime_get_sync(dev->dev);
	ret = drm_irq_install(dev, platform_get_irq(dev->platformdev, 0));
	pm_runtime_put_sync(dev->dev);
	if (ret < 0) {
		dev_err(dev->dev, "failed to install IRQ handler\n");
		goto fail_vblank_cleanup;
	}

	list_for_each_entry(mod, &module_list, list) {
		DBG("%s: preferred_bpp: %d", mod->name, mod->preferred_bpp);
		bpp = mod->preferred_bpp;
		if (bpp > 0)
			break;
	}

	drm_helper_disable_unused_functions(dev);

	drm_mode_config_reset(dev);

	priv->fbdev = drm_fbdev_cma_init(dev, bpp,
			dev->mode_config.num_crtc,
			dev->mode_config.num_connector);
	if (IS_ERR(priv->fbdev)) {
		ret = PTR_ERR(priv->fbdev);
		goto fail_irq_uninstall;
	}

	drm_kms_helper_poll_init(dev);

	return 0;

fail_irq_uninstall:
	pm_runtime_get_sync(dev->dev);
	drm_irq_uninstall(dev);
	pm_runtime_put_sync(dev->dev);

fail_vblank_cleanup:
	drm_vblank_cleanup(dev);

fail_mode_config_cleanup:
	drm_mode_config_cleanup(dev);

fail_component_cleanup:
	if (priv->is_componentized)
		component_unbind_all(dev->dev, dev);

fail_external_cleanup:
	tilcdc_remove_external_encoders(dev);

fail_cpufreq_unregister:
	pm_runtime_disable(dev->dev);
#ifdef CONFIG_CPU_FREQ
	cpufreq_unregister_notifier(&priv->freq_transition,
			CPUFREQ_TRANSITION_NOTIFIER);

fail_put_clk:
#endif
	clk_put(priv->clk);

fail_iounmap:
	iounmap(priv->mmio);

fail_free_wq:
	flush_workqueue(priv->wq);
	destroy_workqueue(priv->wq);

fail_unset_priv:
	dev->dev_private = NULL;

	return ret;
}

static void tilcdc_lastclose(struct drm_device *dev)
{
	struct tilcdc_drm_private *priv = dev->dev_private;
	drm_fbdev_cma_restore_mode(priv->fbdev);
}

static irqreturn_t tilcdc_irq(int irq, void *arg)
{
	struct drm_device *dev = arg;
	struct tilcdc_drm_private *priv = dev->dev_private;
	return tilcdc_crtc_irq(priv->crtc);
}

static void tilcdc_irq_preinstall(struct drm_device *dev)
{
	tilcdc_clear_irqstatus(dev, 0xffffffff);
}

static int tilcdc_irq_postinstall(struct drm_device *dev)
{
	struct tilcdc_drm_private *priv = dev->dev_private;

	/* enable FIFO underflow irq: */
	if (priv->rev == 1) {
		tilcdc_set(dev, LCDC_RASTER_CTRL_REG, LCDC_V1_UNDERFLOW_INT_ENA);
	} else {
		tilcdc_write(dev, LCDC_INT_ENABLE_SET_REG,
			   LCDC_V2_UNDERFLOW_INT_ENA |
			   LCDC_V2_END_OF_FRAME0_INT_ENA |
			   LCDC_FRAME_DONE | LCDC_SYNC_LOST);
	}

	return 0;
}

static void tilcdc_irq_uninstall(struct drm_device *dev)
{
	struct tilcdc_drm_private *priv = dev->dev_private;

	/* disable irqs that we might have enabled: */
	if (priv->rev == 1) {
		tilcdc_clear(dev, LCDC_RASTER_CTRL_REG,
				LCDC_V1_UNDERFLOW_INT_ENA | LCDC_V1_PL_INT_ENA);
		tilcdc_clear(dev, LCDC_DMA_CTRL_REG, LCDC_V1_END_OF_FRAME_INT_ENA);
	} else {
		tilcdc_write(dev, LCDC_INT_ENABLE_CLR_REG,
			LCDC_V2_UNDERFLOW_INT_ENA | LCDC_V2_PL_INT_ENA |
			LCDC_V2_END_OF_FRAME0_INT_ENA |
			LCDC_FRAME_DONE | LCDC_SYNC_LOST);
	}
}

static int tilcdc_enable_vblank(struct drm_device *dev, unsigned int pipe)
{
	return 0;
}

static void tilcdc_disable_vblank(struct drm_device *dev, unsigned int pipe)
{
	return;
}

#if defined(CONFIG_DEBUG_FS) || defined(CONFIG_PM_SLEEP)
static const struct {
	const char *name;
	uint8_t  rev;
	uint8_t  save;
	uint32_t reg;
} registers[] =		{
#define REG(rev, save, reg) { #reg, rev, save, reg }
		/* exists in revision 1: */
		REG(1, false, LCDC_PID_REG),
		REG(1, true,  LCDC_CTRL_REG),
		REG(1, false, LCDC_STAT_REG),
		REG(1, true,  LCDC_RASTER_CTRL_REG),
		REG(1, true,  LCDC_RASTER_TIMING_0_REG),
		REG(1, true,  LCDC_RASTER_TIMING_1_REG),
		REG(1, true,  LCDC_RASTER_TIMING_2_REG),
		REG(1, true,  LCDC_DMA_CTRL_REG),
		REG(1, true,  LCDC_DMA_FB_BASE_ADDR_0_REG),
		REG(1, true,  LCDC_DMA_FB_CEILING_ADDR_0_REG),
		REG(1, true,  LCDC_DMA_FB_BASE_ADDR_1_REG),
		REG(1, true,  LCDC_DMA_FB_CEILING_ADDR_1_REG),
		/* new in revision 2: */
		REG(2, false, LCDC_RAW_STAT_REG),
		REG(2, false, LCDC_MASKED_STAT_REG),
		REG(2, true, LCDC_INT_ENABLE_SET_REG),
		REG(2, false, LCDC_INT_ENABLE_CLR_REG),
		REG(2, false, LCDC_END_OF_INT_IND_REG),
		REG(2, true,  LCDC_CLK_ENABLE_REG),
#undef REG
};

static size_t tilcdc_num_regs(void)
{
	return ARRAY_SIZE(registers);
}
#else
static size_t tilcdc_num_regs(void)
{
	return 0;
}
#endif

#ifdef CONFIG_DEBUG_FS
static int tilcdc_regs_show(struct seq_file *m, void *arg)
{
	struct drm_info_node *node = (struct drm_info_node *) m->private;
	struct drm_device *dev = node->minor->dev;
	struct tilcdc_drm_private *priv = dev->dev_private;
	unsigned i;

	pm_runtime_get_sync(dev->dev);

	seq_printf(m, "revision: %d\n", priv->rev);

	for (i = 0; i < ARRAY_SIZE(registers); i++)
		if (priv->rev >= registers[i].rev)
			seq_printf(m, "%s:\t %08x\n", registers[i].name,
					tilcdc_read(dev, registers[i].reg));

	pm_runtime_put_sync(dev->dev);

	return 0;
}

static int tilcdc_mm_show(struct seq_file *m, void *arg)
{
	struct drm_info_node *node = (struct drm_info_node *) m->private;
	struct drm_device *dev = node->minor->dev;
	return drm_mm_dump_table(m, &dev->vma_offset_manager->vm_addr_space_mm);
}

static struct drm_info_list tilcdc_debugfs_list[] = {
		{ "regs", tilcdc_regs_show, 0 },
		{ "mm",   tilcdc_mm_show,   0 },
		{ "fb",   drm_fb_cma_debugfs_show, 0 },
};

static int tilcdc_debugfs_init(struct drm_minor *minor)
{
	struct drm_device *dev = minor->dev;
	struct tilcdc_module *mod;
	int ret;

	ret = drm_debugfs_create_files(tilcdc_debugfs_list,
			ARRAY_SIZE(tilcdc_debugfs_list),
			minor->debugfs_root, minor);

	list_for_each_entry(mod, &module_list, list)
		if (mod->funcs->debugfs_init)
			mod->funcs->debugfs_init(mod, minor);

	if (ret) {
		dev_err(dev->dev, "could not install tilcdc_debugfs_list\n");
		return ret;
	}

	return ret;
}

static void tilcdc_debugfs_cleanup(struct drm_minor *minor)
{
	struct tilcdc_module *mod;
	drm_debugfs_remove_files(tilcdc_debugfs_list,
			ARRAY_SIZE(tilcdc_debugfs_list), minor);

	list_for_each_entry(mod, &module_list, list)
		if (mod->funcs->debugfs_cleanup)
			mod->funcs->debugfs_cleanup(mod, minor);
}
#endif

static const struct file_operations fops = {
	.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               = drm_gem_cma_mmap,
};

static struct drm_driver tilcdc_driver = {
	.driver_features    = (DRIVER_HAVE_IRQ | DRIVER_GEM | DRIVER_MODESET |
			       DRIVER_PRIME),
	.load               = tilcdc_load,
	.unload             = tilcdc_unload,
	.lastclose          = tilcdc_lastclose,
	.irq_handler        = tilcdc_irq,
	.irq_preinstall     = tilcdc_irq_preinstall,
	.irq_postinstall    = tilcdc_irq_postinstall,
	.irq_uninstall      = tilcdc_irq_uninstall,
	.get_vblank_counter = drm_vblank_no_hw_counter,
	.enable_vblank      = tilcdc_enable_vblank,
	.disable_vblank     = tilcdc_disable_vblank,
	.gem_free_object_unlocked = drm_gem_cma_free_object,
	.gem_vm_ops         = &drm_gem_cma_vm_ops,
	.dumb_create        = drm_gem_cma_dumb_create,
	.dumb_map_offset    = drm_gem_cma_dumb_map_offset,
	.dumb_destroy       = drm_gem_dumb_destroy,

	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd,
	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle,
	.gem_prime_import	= drm_gem_prime_import,
	.gem_prime_export	= drm_gem_prime_export,
	.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,
#ifdef CONFIG_DEBUG_FS
	.debugfs_init       = tilcdc_debugfs_init,
	.debugfs_cleanup    = tilcdc_debugfs_cleanup,
#endif
	.fops               = &fops,
	.name               = "tilcdc",
	.desc               = "TI LCD Controller DRM",
	.date               = "20121205",
	.major              = 1,
	.minor              = 0,
};

/*
 * Power management:
 */

#ifdef CONFIG_PM_SLEEP
static int tilcdc_pm_suspend(struct device *dev)
{
	struct drm_device *ddev = dev_get_drvdata(dev);
	struct tilcdc_drm_private *priv = ddev->dev_private;
	unsigned i, n = 0;

	drm_kms_helper_poll_disable(ddev);

	/* Select sleep pin state */
	pinctrl_pm_select_sleep_state(dev);

	if (pm_runtime_suspended(dev)) {
		priv->ctx_valid = false;
		return 0;
	}

	/* Disable the LCDC controller, to avoid locking up the PRCM */
	priv->saved_dpms_state = tilcdc_crtc_current_dpms_state(priv->crtc);
	tilcdc_crtc_dpms(priv->crtc, DRM_MODE_DPMS_OFF);

	/* Save register state: */
	for (i = 0; i < ARRAY_SIZE(registers); i++)
		if (registers[i].save && (priv->rev >= registers[i].rev))
			priv->saved_register[n++] = tilcdc_read(ddev, registers[i].reg);

	priv->ctx_valid = true;

	return 0;
}

static int tilcdc_pm_resume(struct device *dev)
{
	struct drm_device *ddev = dev_get_drvdata(dev);
	struct tilcdc_drm_private *priv = ddev->dev_private;
	unsigned i, n = 0;

	/* Select default pin state */
	pinctrl_pm_select_default_state(dev);

	if (priv->ctx_valid == true) {
		/* Restore register state: */
		for (i = 0; i < ARRAY_SIZE(registers); i++)
			if (registers[i].save &&
			    (priv->rev >= registers[i].rev))
				tilcdc_write(ddev, registers[i].reg,
					     priv->saved_register[n++]);
	}

	tilcdc_crtc_dpms(priv->crtc, priv->saved_dpms_state);

	drm_kms_helper_poll_enable(ddev);

	return 0;
}
#endif

static const struct dev_pm_ops tilcdc_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(tilcdc_pm_suspend, tilcdc_pm_resume)
};

/*
 * Platform driver:
 */

static int tilcdc_bind(struct device *dev)
{
	return drm_platform_init(&tilcdc_driver, to_platform_device(dev));
}

static void tilcdc_unbind(struct device *dev)
{
	struct drm_device *ddev = dev_get_drvdata(dev);

	/* Check if a subcomponent has already triggered the unloading. */
	if (!ddev->dev_private)
		return;

	drm_put_dev(dev_get_drvdata(dev));
}

static const struct component_master_ops tilcdc_comp_ops = {
	.bind = tilcdc_bind,
	.unbind = tilcdc_unbind,
};

static int tilcdc_pdev_probe(struct platform_device *pdev)
{
	struct component_match *match = NULL;
	int ret;

	/* bail out early if no DT data: */
	if (!pdev->dev.of_node) {
		dev_err(&pdev->dev, "device-tree data is missing\n");
		return -ENXIO;
	}

	ret = tilcdc_get_external_components(&pdev->dev, &match);
	if (ret < 0)
		return ret;
	else if (ret == 0)
		return drm_platform_init(&tilcdc_driver, pdev);
	else
		return component_master_add_with_match(&pdev->dev,
						       &tilcdc_comp_ops,
						       match);
}

static int tilcdc_pdev_remove(struct platform_device *pdev)
{
	int ret;

	ret = tilcdc_get_external_components(&pdev->dev, NULL);
	if (ret < 0)
		return ret;
	else if (ret == 0)
		drm_put_dev(platform_get_drvdata(pdev));
	else
		component_master_del(&pdev->dev, &tilcdc_comp_ops);

	return 0;
}

static struct of_device_id tilcdc_of_match[] = {
		{ .compatible = "ti,am33xx-tilcdc", },
		{ },
};
MODULE_DEVICE_TABLE(of, tilcdc_of_match);

static struct platform_driver tilcdc_platform_driver = {
	.probe      = tilcdc_pdev_probe,
	.remove     = tilcdc_pdev_remove,
	.driver     = {
		.name   = "tilcdc",
		.pm     = &tilcdc_pm_ops,
		.of_match_table = tilcdc_of_match,
	},
};

static int __init tilcdc_drm_init(void)
{
	DBG("init");
	tilcdc_tfp410_init();
	tilcdc_panel_init();
	return platform_driver_register(&tilcdc_platform_driver);
}

static void __exit tilcdc_drm_fini(void)
{
	DBG("fini");
	platform_driver_unregister(&tilcdc_platform_driver);
	tilcdc_panel_fini();
	tilcdc_tfp410_fini();
}

module_init(tilcdc_drm_init);
module_exit(tilcdc_drm_fini);

MODULE_AUTHOR("Rob Clark <robdclark@gmail.com");
MODULE_DESCRIPTION("TI LCD Controller DRM Driver");
MODULE_LICENSE("GPL");