// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2014 Traphandler
 * Copyright (C) 2014 Free Electrons
 * Copyright (C) 2014 Atmel
 *
 * Author: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
 * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
 */

#include <linux/clk.h>
#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/mfd/atmel-hlcdc.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/platform_device.h>

#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_drv.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_vblank.h>

#include "atmel_hlcdc_dc.h"

#define ATMEL_HLCDC_LAYER_IRQS_OFFSET		8

static const struct atmel_hlcdc_layer_desc atmel_hlcdc_at91sam9n12_layers[] = {
	{
		.name = "base",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x40,
		.id = 0,
		.type = ATMEL_HLCDC_BASE_LAYER,
		.cfgs_offset = 0x2c,
		.layout = {
			.xstride = { 2 },
			.default_color = 3,
			.general_config = 4,
		},
		.clut_offset = 0x400,
	},
};

static const struct atmel_hlcdc_dc_desc atmel_hlcdc_dc_at91sam9n12 = {
	.min_width = 0,
	.min_height = 0,
	.max_width = 1280,
	.max_height = 860,
	.max_spw = 0x3f,
	.max_vpw = 0x3f,
	.max_hpw = 0xff,
	.conflicting_output_formats = true,
	.nlayers = ARRAY_SIZE(atmel_hlcdc_at91sam9n12_layers),
	.layers = atmel_hlcdc_at91sam9n12_layers,
};

static const struct atmel_hlcdc_layer_desc atmel_hlcdc_at91sam9x5_layers[] = {
	{
		.name = "base",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x40,
		.id = 0,
		.type = ATMEL_HLCDC_BASE_LAYER,
		.cfgs_offset = 0x2c,
		.layout = {
			.xstride = { 2 },
			.default_color = 3,
			.general_config = 4,
			.disc_pos = 5,
			.disc_size = 6,
		},
		.clut_offset = 0x400,
	},
	{
		.name = "overlay1",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x100,
		.id = 1,
		.type = ATMEL_HLCDC_OVERLAY_LAYER,
		.cfgs_offset = 0x2c,
		.layout = {
			.pos = 2,
			.size = 3,
			.xstride = { 4 },
			.pstride = { 5 },
			.default_color = 6,
			.chroma_key = 7,
			.chroma_key_mask = 8,
			.general_config = 9,
		},
		.clut_offset = 0x800,
	},
	{
		.name = "high-end-overlay",
		.formats = &atmel_hlcdc_plane_rgb_and_yuv_formats,
		.regs_offset = 0x280,
		.id = 2,
		.type = ATMEL_HLCDC_OVERLAY_LAYER,
		.cfgs_offset = 0x4c,
		.layout = {
			.pos = 2,
			.size = 3,
			.memsize = 4,
			.xstride = { 5, 7 },
			.pstride = { 6, 8 },
			.default_color = 9,
			.chroma_key = 10,
			.chroma_key_mask = 11,
			.general_config = 12,
			.scaler_config = 13,
			.csc = 14,
		},
		.clut_offset = 0x1000,
	},
	{
		.name = "cursor",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x340,
		.id = 3,
		.type = ATMEL_HLCDC_CURSOR_LAYER,
		.max_width = 128,
		.max_height = 128,
		.cfgs_offset = 0x2c,
		.layout = {
			.pos = 2,
			.size = 3,
			.xstride = { 4 },
			.default_color = 6,
			.chroma_key = 7,
			.chroma_key_mask = 8,
			.general_config = 9,
		},
		.clut_offset = 0x1400,
	},
};

static const struct atmel_hlcdc_dc_desc atmel_hlcdc_dc_at91sam9x5 = {
	.min_width = 0,
	.min_height = 0,
	.max_width = 800,
	.max_height = 600,
	.max_spw = 0x3f,
	.max_vpw = 0x3f,
	.max_hpw = 0xff,
	.conflicting_output_formats = true,
	.nlayers = ARRAY_SIZE(atmel_hlcdc_at91sam9x5_layers),
	.layers = atmel_hlcdc_at91sam9x5_layers,
};

static const struct atmel_hlcdc_layer_desc atmel_hlcdc_sama5d3_layers[] = {
	{
		.name = "base",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x40,
		.id = 0,
		.type = ATMEL_HLCDC_BASE_LAYER,
		.cfgs_offset = 0x2c,
		.layout = {
			.xstride = { 2 },
			.default_color = 3,
			.general_config = 4,
			.disc_pos = 5,
			.disc_size = 6,
		},
		.clut_offset = 0x600,
	},
	{
		.name = "overlay1",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x140,
		.id = 1,
		.type = ATMEL_HLCDC_OVERLAY_LAYER,
		.cfgs_offset = 0x2c,
		.layout = {
			.pos = 2,
			.size = 3,
			.xstride = { 4 },
			.pstride = { 5 },
			.default_color = 6,
			.chroma_key = 7,
			.chroma_key_mask = 8,
			.general_config = 9,
		},
		.clut_offset = 0xa00,
	},
	{
		.name = "overlay2",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x240,
		.id = 2,
		.type = ATMEL_HLCDC_OVERLAY_LAYER,
		.cfgs_offset = 0x2c,
		.layout = {
			.pos = 2,
			.size = 3,
			.xstride = { 4 },
			.pstride = { 5 },
			.default_color = 6,
			.chroma_key = 7,
			.chroma_key_mask = 8,
			.general_config = 9,
		},
		.clut_offset = 0xe00,
	},
	{
		.name = "high-end-overlay",
		.formats = &atmel_hlcdc_plane_rgb_and_yuv_formats,
		.regs_offset = 0x340,
		.id = 3,
		.type = ATMEL_HLCDC_OVERLAY_LAYER,
		.cfgs_offset = 0x4c,
		.layout = {
			.pos = 2,
			.size = 3,
			.memsize = 4,
			.xstride = { 5, 7 },
			.pstride = { 6, 8 },
			.default_color = 9,
			.chroma_key = 10,
			.chroma_key_mask = 11,
			.general_config = 12,
			.scaler_config = 13,
			.phicoeffs = {
				.x = 17,
				.y = 33,
			},
			.csc = 14,
		},
		.clut_offset = 0x1200,
	},
	{
		.name = "cursor",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x440,
		.id = 4,
		.type = ATMEL_HLCDC_CURSOR_LAYER,
		.max_width = 128,
		.max_height = 128,
		.cfgs_offset = 0x2c,
		.layout = {
			.pos = 2,
			.size = 3,
			.xstride = { 4 },
			.pstride = { 5 },
			.default_color = 6,
			.chroma_key = 7,
			.chroma_key_mask = 8,
			.general_config = 9,
			.scaler_config = 13,
		},
		.clut_offset = 0x1600,
	},
};

static const struct atmel_hlcdc_dc_desc atmel_hlcdc_dc_sama5d3 = {
	.min_width = 0,
	.min_height = 0,
	.max_width = 2048,
	.max_height = 2048,
	.max_spw = 0x3f,
	.max_vpw = 0x3f,
	.max_hpw = 0x1ff,
	.conflicting_output_formats = true,
	.nlayers = ARRAY_SIZE(atmel_hlcdc_sama5d3_layers),
	.layers = atmel_hlcdc_sama5d3_layers,
};

static const struct atmel_hlcdc_layer_desc atmel_hlcdc_sama5d4_layers[] = {
	{
		.name = "base",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x40,
		.id = 0,
		.type = ATMEL_HLCDC_BASE_LAYER,
		.cfgs_offset = 0x2c,
		.layout = {
			.xstride = { 2 },
			.default_color = 3,
			.general_config = 4,
			.disc_pos = 5,
			.disc_size = 6,
		},
		.clut_offset = 0x600,
	},
	{
		.name = "overlay1",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x140,
		.id = 1,
		.type = ATMEL_HLCDC_OVERLAY_LAYER,
		.cfgs_offset = 0x2c,
		.layout = {
			.pos = 2,
			.size = 3,
			.xstride = { 4 },
			.pstride = { 5 },
			.default_color = 6,
			.chroma_key = 7,
			.chroma_key_mask = 8,
			.general_config = 9,
		},
		.clut_offset = 0xa00,
	},
	{
		.name = "overlay2",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x240,
		.id = 2,
		.type = ATMEL_HLCDC_OVERLAY_LAYER,
		.cfgs_offset = 0x2c,
		.layout = {
			.pos = 2,
			.size = 3,
			.xstride = { 4 },
			.pstride = { 5 },
			.default_color = 6,
			.chroma_key = 7,
			.chroma_key_mask = 8,
			.general_config = 9,
		},
		.clut_offset = 0xe00,
	},
	{
		.name = "high-end-overlay",
		.formats = &atmel_hlcdc_plane_rgb_and_yuv_formats,
		.regs_offset = 0x340,
		.id = 3,
		.type = ATMEL_HLCDC_OVERLAY_LAYER,
		.cfgs_offset = 0x4c,
		.layout = {
			.pos = 2,
			.size = 3,
			.memsize = 4,
			.xstride = { 5, 7 },
			.pstride = { 6, 8 },
			.default_color = 9,
			.chroma_key = 10,
			.chroma_key_mask = 11,
			.general_config = 12,
			.scaler_config = 13,
			.phicoeffs = {
				.x = 17,
				.y = 33,
			},
			.csc = 14,
		},
		.clut_offset = 0x1200,
	},
};

static const struct atmel_hlcdc_dc_desc atmel_hlcdc_dc_sama5d4 = {
	.min_width = 0,
	.min_height = 0,
	.max_width = 2048,
	.max_height = 2048,
	.max_spw = 0xff,
	.max_vpw = 0xff,
	.max_hpw = 0x3ff,
	.nlayers = ARRAY_SIZE(atmel_hlcdc_sama5d4_layers),
	.layers = atmel_hlcdc_sama5d4_layers,
};

static const struct atmel_hlcdc_layer_desc atmel_hlcdc_sam9x60_layers[] = {
	{
		.name = "base",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x60,
		.id = 0,
		.type = ATMEL_HLCDC_BASE_LAYER,
		.cfgs_offset = 0x2c,
		.layout = {
			.xstride = { 2 },
			.default_color = 3,
			.general_config = 4,
			.disc_pos = 5,
			.disc_size = 6,
		},
		.clut_offset = 0x600,
	},
	{
		.name = "overlay1",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x160,
		.id = 1,
		.type = ATMEL_HLCDC_OVERLAY_LAYER,
		.cfgs_offset = 0x2c,
		.layout = {
			.pos = 2,
			.size = 3,
			.xstride = { 4 },
			.pstride = { 5 },
			.default_color = 6,
			.chroma_key = 7,
			.chroma_key_mask = 8,
			.general_config = 9,
		},
		.clut_offset = 0xa00,
	},
	{
		.name = "overlay2",
		.formats = &atmel_hlcdc_plane_rgb_formats,
		.regs_offset = 0x260,
		.id = 2,
		.type = ATMEL_HLCDC_OVERLAY_LAYER,
		.cfgs_offset = 0x2c,
		.layout = {
			.pos = 2,
			.size = 3,
			.xstride = { 4 },
			.pstride = { 5 },
			.default_color = 6,
			.chroma_key = 7,
			.chroma_key_mask = 8,
			.general_config = 9,
		},
		.clut_offset = 0xe00,
	},
	{
		.name = "high-end-overlay",
		.formats = &atmel_hlcdc_plane_rgb_and_yuv_formats,
		.regs_offset = 0x360,
		.id = 3,
		.type = ATMEL_HLCDC_OVERLAY_LAYER,
		.cfgs_offset = 0x4c,
		.layout = {
			.pos = 2,
			.size = 3,
			.memsize = 4,
			.xstride = { 5, 7 },
			.pstride = { 6, 8 },
			.default_color = 9,
			.chroma_key = 10,
			.chroma_key_mask = 11,
			.general_config = 12,
			.scaler_config = 13,
			.phicoeffs = {
				.x = 17,
				.y = 33,
			},
			.csc = 14,
		},
		.clut_offset = 0x1200,
	},
};

static const struct atmel_hlcdc_dc_desc atmel_hlcdc_dc_sam9x60 = {
	.min_width = 0,
	.min_height = 0,
	.max_width = 2048,
	.max_height = 2048,
	.max_spw = 0xff,
	.max_vpw = 0xff,
	.max_hpw = 0x3ff,
	.fixed_clksrc = true,
	.nlayers = ARRAY_SIZE(atmel_hlcdc_sam9x60_layers),
	.layers = atmel_hlcdc_sam9x60_layers,
};

static const struct of_device_id atmel_hlcdc_of_match[] = {
	{
		.compatible = "atmel,at91sam9n12-hlcdc",
		.data = &atmel_hlcdc_dc_at91sam9n12,
	},
	{
		.compatible = "atmel,at91sam9x5-hlcdc",
		.data = &atmel_hlcdc_dc_at91sam9x5,
	},
	{
		.compatible = "atmel,sama5d2-hlcdc",
		.data = &atmel_hlcdc_dc_sama5d4,
	},
	{
		.compatible = "atmel,sama5d3-hlcdc",
		.data = &atmel_hlcdc_dc_sama5d3,
	},
	{
		.compatible = "atmel,sama5d4-hlcdc",
		.data = &atmel_hlcdc_dc_sama5d4,
	},
	{
		.compatible = "microchip,sam9x60-hlcdc",
		.data = &atmel_hlcdc_dc_sam9x60,
	},
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, atmel_hlcdc_of_match);

enum drm_mode_status
atmel_hlcdc_dc_mode_valid(struct atmel_hlcdc_dc *dc,
			  const struct drm_display_mode *mode)
{
	int vfront_porch = mode->vsync_start - mode->vdisplay;
	int vback_porch = mode->vtotal - mode->vsync_end;
	int vsync_len = mode->vsync_end - mode->vsync_start;
	int hfront_porch = mode->hsync_start - mode->hdisplay;
	int hback_porch = mode->htotal - mode->hsync_end;
	int hsync_len = mode->hsync_end - mode->hsync_start;

	if (hsync_len > dc->desc->max_spw + 1 || hsync_len < 1)
		return MODE_HSYNC;

	if (vsync_len > dc->desc->max_spw + 1 || vsync_len < 1)
		return MODE_VSYNC;

	if (hfront_porch > dc->desc->max_hpw + 1 || hfront_porch < 1 ||
	    hback_porch > dc->desc->max_hpw + 1 || hback_porch < 1 ||
	    mode->hdisplay < 1)
		return MODE_H_ILLEGAL;

	if (vfront_porch > dc->desc->max_vpw + 1 || vfront_porch < 1 ||
	    vback_porch > dc->desc->max_vpw || vback_porch < 0 ||
	    mode->vdisplay < 1)
		return MODE_V_ILLEGAL;

	return MODE_OK;
}

static void atmel_hlcdc_layer_irq(struct atmel_hlcdc_layer *layer)
{
	if (!layer)
		return;

	if (layer->desc->type == ATMEL_HLCDC_BASE_LAYER ||
	    layer->desc->type == ATMEL_HLCDC_OVERLAY_LAYER ||
	    layer->desc->type == ATMEL_HLCDC_CURSOR_LAYER)
		atmel_hlcdc_plane_irq(atmel_hlcdc_layer_to_plane(layer));
}

static irqreturn_t atmel_hlcdc_dc_irq_handler(int irq, void *data)
{
	struct drm_device *dev = data;
	struct atmel_hlcdc_dc *dc = dev->dev_private;
	unsigned long status;
	unsigned int imr, isr;
	int i;

	regmap_read(dc->hlcdc->regmap, ATMEL_HLCDC_IMR, &imr);
	regmap_read(dc->hlcdc->regmap, ATMEL_HLCDC_ISR, &isr);
	status = imr & isr;
	if (!status)
		return IRQ_NONE;

	if (status & ATMEL_HLCDC_SOF)
		atmel_hlcdc_crtc_irq(dc->crtc);

	for (i = 0; i < ATMEL_HLCDC_MAX_LAYERS; i++) {
		if (ATMEL_HLCDC_LAYER_STATUS(i) & status)
			atmel_hlcdc_layer_irq(dc->layers[i]);
	}

	return IRQ_HANDLED;
}

static void atmel_hlcdc_dc_irq_postinstall(struct drm_device *dev)
{
	struct atmel_hlcdc_dc *dc = dev->dev_private;
	unsigned int cfg = 0;
	int i;

	/* Enable interrupts on activated layers */
	for (i = 0; i < ATMEL_HLCDC_MAX_LAYERS; i++) {
		if (dc->layers[i])
			cfg |= ATMEL_HLCDC_LAYER_STATUS(i);
	}

	regmap_write(dc->hlcdc->regmap, ATMEL_HLCDC_IER, cfg);
}

static void atmel_hlcdc_dc_irq_disable(struct drm_device *dev)
{
	struct atmel_hlcdc_dc *dc = dev->dev_private;
	unsigned int isr;

	regmap_write(dc->hlcdc->regmap, ATMEL_HLCDC_IDR, 0xffffffff);
	regmap_read(dc->hlcdc->regmap, ATMEL_HLCDC_ISR, &isr);
}

static int atmel_hlcdc_dc_irq_install(struct drm_device *dev, unsigned int irq)
{
	int ret;

	atmel_hlcdc_dc_irq_disable(dev);

	ret = devm_request_irq(dev->dev, irq, atmel_hlcdc_dc_irq_handler, 0,
			       dev->driver->name, dev);
	if (ret)
		return ret;

	atmel_hlcdc_dc_irq_postinstall(dev);

	return 0;
}

static void atmel_hlcdc_dc_irq_uninstall(struct drm_device *dev)
{
	atmel_hlcdc_dc_irq_disable(dev);
}

static const struct drm_mode_config_funcs mode_config_funcs = {
	.fb_create = drm_gem_fb_create,
	.atomic_check = drm_atomic_helper_check,
	.atomic_commit = drm_atomic_helper_commit,
};

static int atmel_hlcdc_dc_modeset_init(struct drm_device *dev)
{
	struct atmel_hlcdc_dc *dc = dev->dev_private;
	int ret;

	drm_mode_config_init(dev);

	ret = atmel_hlcdc_create_outputs(dev);
	if (ret) {
		dev_err(dev->dev, "failed to create HLCDC outputs: %d\n", ret);
		return ret;
	}

	ret = atmel_hlcdc_create_planes(dev);
	if (ret) {
		dev_err(dev->dev, "failed to create planes: %d\n", ret);
		return ret;
	}

	ret = atmel_hlcdc_crtc_create(dev);
	if (ret) {
		dev_err(dev->dev, "failed to create crtc\n");
		return ret;
	}

	dev->mode_config.min_width = dc->desc->min_width;
	dev->mode_config.min_height = dc->desc->min_height;
	dev->mode_config.max_width = dc->desc->max_width;
	dev->mode_config.max_height = dc->desc->max_height;
	dev->mode_config.funcs = &mode_config_funcs;
	dev->mode_config.async_page_flip = true;

	return 0;
}

static int atmel_hlcdc_dc_load(struct drm_device *dev)
{
	struct platform_device *pdev = to_platform_device(dev->dev);
	const struct of_device_id *match;
	struct atmel_hlcdc_dc *dc;
	int ret;

	match = of_match_node(atmel_hlcdc_of_match, dev->dev->parent->of_node);
	if (!match) {
		dev_err(&pdev->dev, "invalid compatible string\n");
		return -ENODEV;
	}

	if (!match->data) {
		dev_err(&pdev->dev, "invalid hlcdc description\n");
		return -EINVAL;
	}

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

	dc->desc = match->data;
	dc->hlcdc = dev_get_drvdata(dev->dev->parent);
	dev->dev_private = dc;

	ret = clk_prepare_enable(dc->hlcdc->periph_clk);
	if (ret) {
		dev_err(dev->dev, "failed to enable periph_clk\n");
		return ret;
	}

	pm_runtime_enable(dev->dev);

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

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

	drm_mode_config_reset(dev);

	pm_runtime_get_sync(dev->dev);
	ret = atmel_hlcdc_dc_irq_install(dev, dc->hlcdc->irq);
	pm_runtime_put_sync(dev->dev);
	if (ret < 0) {
		dev_err(dev->dev, "failed to install IRQ handler\n");
		goto err_periph_clk_disable;
	}

	platform_set_drvdata(pdev, dev);

	drm_kms_helper_poll_init(dev);

	return 0;

err_periph_clk_disable:
	pm_runtime_disable(dev->dev);
	clk_disable_unprepare(dc->hlcdc->periph_clk);

	return ret;
}

static void atmel_hlcdc_dc_unload(struct drm_device *dev)
{
	struct atmel_hlcdc_dc *dc = dev->dev_private;

	drm_kms_helper_poll_fini(dev);
	drm_atomic_helper_shutdown(dev);
	drm_mode_config_cleanup(dev);

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

	dev->dev_private = NULL;

	pm_runtime_disable(dev->dev);
	clk_disable_unprepare(dc->hlcdc->periph_clk);
}

DEFINE_DRM_GEM_CMA_FOPS(fops);

static const struct drm_driver atmel_hlcdc_dc_driver = {
	.driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
	DRM_GEM_CMA_DRIVER_OPS,
	.fops = &fops,
	.name = "atmel-hlcdc",
	.desc = "Atmel HLCD Controller DRM",
	.date = "20141504",
	.major = 1,
	.minor = 0,
};

static int atmel_hlcdc_dc_drm_probe(struct platform_device *pdev)
{
	struct drm_device *ddev;
	int ret;

	ddev = drm_dev_alloc(&atmel_hlcdc_dc_driver, &pdev->dev);
	if (IS_ERR(ddev))
		return PTR_ERR(ddev);

	ret = atmel_hlcdc_dc_load(ddev);
	if (ret)
		goto err_put;

	ret = drm_dev_register(ddev, 0);
	if (ret)
		goto err_unload;

	drm_fbdev_generic_setup(ddev, 24);

	return 0;

err_unload:
	atmel_hlcdc_dc_unload(ddev);

err_put:
	drm_dev_put(ddev);

	return ret;
}

static int atmel_hlcdc_dc_drm_remove(struct platform_device *pdev)
{
	struct drm_device *ddev = platform_get_drvdata(pdev);

	drm_dev_unregister(ddev);
	atmel_hlcdc_dc_unload(ddev);
	drm_dev_put(ddev);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int atmel_hlcdc_dc_drm_suspend(struct device *dev)
{
	struct drm_device *drm_dev = dev_get_drvdata(dev);
	struct atmel_hlcdc_dc *dc = drm_dev->dev_private;
	struct regmap *regmap = dc->hlcdc->regmap;
	struct drm_atomic_state *state;

	state = drm_atomic_helper_suspend(drm_dev);
	if (IS_ERR(state))
		return PTR_ERR(state);

	dc->suspend.state = state;

	regmap_read(regmap, ATMEL_HLCDC_IMR, &dc->suspend.imr);
	regmap_write(regmap, ATMEL_HLCDC_IDR, dc->suspend.imr);
	clk_disable_unprepare(dc->hlcdc->periph_clk);

	return 0;
}

static int atmel_hlcdc_dc_drm_resume(struct device *dev)
{
	struct drm_device *drm_dev = dev_get_drvdata(dev);
	struct atmel_hlcdc_dc *dc = drm_dev->dev_private;

	clk_prepare_enable(dc->hlcdc->periph_clk);
	regmap_write(dc->hlcdc->regmap, ATMEL_HLCDC_IER, dc->suspend.imr);

	return drm_atomic_helper_resume(drm_dev, dc->suspend.state);
}
#endif

static SIMPLE_DEV_PM_OPS(atmel_hlcdc_dc_drm_pm_ops,
		atmel_hlcdc_dc_drm_suspend, atmel_hlcdc_dc_drm_resume);

static const struct of_device_id atmel_hlcdc_dc_of_match[] = {
	{ .compatible = "atmel,hlcdc-display-controller" },
	{ },
};

static struct platform_driver atmel_hlcdc_dc_platform_driver = {
	.probe	= atmel_hlcdc_dc_drm_probe,
	.remove	= atmel_hlcdc_dc_drm_remove,
	.driver	= {
		.name	= "atmel-hlcdc-display-controller",
		.pm	= &atmel_hlcdc_dc_drm_pm_ops,
		.of_match_table = atmel_hlcdc_dc_of_match,
	},
};
module_platform_driver(atmel_hlcdc_dc_platform_driver);

MODULE_AUTHOR("Jean-Jacques Hiblot <jjhiblot@traphandler.com>");
MODULE_AUTHOR("Boris Brezillon <boris.brezillon@free-electrons.com>");
MODULE_DESCRIPTION("Atmel HLCDC Display Controller DRM Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:atmel-hlcdc-dc");