/*
 * Copyright (C) 2012 Avionic Design GmbH
 * Copyright (C) 2012 NVIDIA CORPORATION.  All rights reserved.
 *
 * 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.
 */

#include <linux/clk.h>

#include "drm.h"
#include "dc.h"

struct tegra_rgb {
	struct tegra_output output;
	struct tegra_dc *dc;
	bool enabled;

	struct clk *clk_parent;
	struct clk *clk;
};

static inline struct tegra_rgb *to_rgb(struct tegra_output *output)
{
	return container_of(output, struct tegra_rgb, output);
}

struct reg_entry {
	unsigned long offset;
	unsigned long value;
};

static const struct reg_entry rgb_enable[] = {
	{ DC_COM_PIN_OUTPUT_ENABLE(0),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_ENABLE(1),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_ENABLE(2),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_ENABLE(3),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_POLARITY(0), 0x00000000 },
	{ DC_COM_PIN_OUTPUT_POLARITY(1), 0x01000000 },
	{ DC_COM_PIN_OUTPUT_POLARITY(2), 0x00000000 },
	{ DC_COM_PIN_OUTPUT_POLARITY(3), 0x00000000 },
	{ DC_COM_PIN_OUTPUT_DATA(0),     0x00000000 },
	{ DC_COM_PIN_OUTPUT_DATA(1),     0x00000000 },
	{ DC_COM_PIN_OUTPUT_DATA(2),     0x00000000 },
	{ DC_COM_PIN_OUTPUT_DATA(3),     0x00000000 },
	{ DC_COM_PIN_OUTPUT_SELECT(0),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_SELECT(1),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_SELECT(2),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_SELECT(3),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_SELECT(4),   0x00210222 },
	{ DC_COM_PIN_OUTPUT_SELECT(5),   0x00002200 },
	{ DC_COM_PIN_OUTPUT_SELECT(6),   0x00020000 },
};

static const struct reg_entry rgb_disable[] = {
	{ DC_COM_PIN_OUTPUT_SELECT(6),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_SELECT(5),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_SELECT(4),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_SELECT(3),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_SELECT(2),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_SELECT(1),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_SELECT(0),   0x00000000 },
	{ DC_COM_PIN_OUTPUT_DATA(3),     0xaaaaaaaa },
	{ DC_COM_PIN_OUTPUT_DATA(2),     0xaaaaaaaa },
	{ DC_COM_PIN_OUTPUT_DATA(1),     0xaaaaaaaa },
	{ DC_COM_PIN_OUTPUT_DATA(0),     0xaaaaaaaa },
	{ DC_COM_PIN_OUTPUT_POLARITY(3), 0x00000000 },
	{ DC_COM_PIN_OUTPUT_POLARITY(2), 0x00000000 },
	{ DC_COM_PIN_OUTPUT_POLARITY(1), 0x00000000 },
	{ DC_COM_PIN_OUTPUT_POLARITY(0), 0x00000000 },
	{ DC_COM_PIN_OUTPUT_ENABLE(3),   0x55555555 },
	{ DC_COM_PIN_OUTPUT_ENABLE(2),   0x55555555 },
	{ DC_COM_PIN_OUTPUT_ENABLE(1),   0x55150005 },
	{ DC_COM_PIN_OUTPUT_ENABLE(0),   0x55555555 },
};

static void tegra_dc_write_regs(struct tegra_dc *dc,
				const struct reg_entry *table,
				unsigned int num)
{
	unsigned int i;

	for (i = 0; i < num; i++)
		tegra_dc_writel(dc, table[i].value, table[i].offset);
}

static int tegra_output_rgb_enable(struct tegra_output *output)
{
	struct tegra_rgb *rgb = to_rgb(output);
	unsigned long value;

	if (rgb->enabled)
		return 0;

	tegra_dc_write_regs(rgb->dc, rgb_enable, ARRAY_SIZE(rgb_enable));

	value = DE_SELECT_ACTIVE | DE_CONTROL_NORMAL;
	tegra_dc_writel(rgb->dc, value, DC_DISP_DATA_ENABLE_OPTIONS);

	/* XXX: parameterize? */
	value = tegra_dc_readl(rgb->dc, DC_COM_PIN_OUTPUT_POLARITY(1));
	value &= ~LVS_OUTPUT_POLARITY_LOW;
	value &= ~LHS_OUTPUT_POLARITY_LOW;
	tegra_dc_writel(rgb->dc, value, DC_COM_PIN_OUTPUT_POLARITY(1));

	/* XXX: parameterize? */
	value = DISP_DATA_FORMAT_DF1P1C | DISP_ALIGNMENT_MSB |
		DISP_ORDER_RED_BLUE;
	tegra_dc_writel(rgb->dc, value, DC_DISP_DISP_INTERFACE_CONTROL);

	/* XXX: parameterize? */
	value = SC0_H_QUALIFIER_NONE | SC1_H_QUALIFIER_NONE;
	tegra_dc_writel(rgb->dc, value, DC_DISP_SHIFT_CLOCK_OPTIONS);

	value = tegra_dc_readl(rgb->dc, DC_CMD_DISPLAY_COMMAND);
	value &= ~DISP_CTRL_MODE_MASK;
	value |= DISP_CTRL_MODE_C_DISPLAY;
	tegra_dc_writel(rgb->dc, value, DC_CMD_DISPLAY_COMMAND);

	value = tegra_dc_readl(rgb->dc, DC_CMD_DISPLAY_POWER_CONTROL);
	value |= PW0_ENABLE | PW1_ENABLE | PW2_ENABLE | PW3_ENABLE |
		 PW4_ENABLE | PM0_ENABLE | PM1_ENABLE;
	tegra_dc_writel(rgb->dc, value, DC_CMD_DISPLAY_POWER_CONTROL);

	tegra_dc_commit(rgb->dc);

	rgb->enabled = true;

	return 0;
}

static int tegra_output_rgb_disable(struct tegra_output *output)
{
	struct tegra_rgb *rgb = to_rgb(output);
	unsigned long value;

	if (!rgb->enabled)
		return 0;

	value = tegra_dc_readl(rgb->dc, DC_CMD_DISPLAY_POWER_CONTROL);
	value &= ~(PW0_ENABLE | PW1_ENABLE | PW2_ENABLE | PW3_ENABLE |
		   PW4_ENABLE | PM0_ENABLE | PM1_ENABLE);
	tegra_dc_writel(rgb->dc, value, DC_CMD_DISPLAY_POWER_CONTROL);

	value = tegra_dc_readl(rgb->dc, DC_CMD_DISPLAY_COMMAND);
	value &= ~DISP_CTRL_MODE_MASK;
	tegra_dc_writel(rgb->dc, value, DC_CMD_DISPLAY_COMMAND);

	tegra_dc_write_regs(rgb->dc, rgb_disable, ARRAY_SIZE(rgb_disable));

	tegra_dc_commit(rgb->dc);

	rgb->enabled = false;

	return 0;
}

static int tegra_output_rgb_setup_clock(struct tegra_output *output,
					struct clk *clk, unsigned long pclk,
					unsigned int *div)
{
	struct tegra_rgb *rgb = to_rgb(output);
	int err;

	err = clk_set_parent(clk, rgb->clk_parent);
	if (err < 0) {
		dev_err(output->dev, "failed to set parent: %d\n", err);
		return err;
	}

	/*
	 * We may not want to change the frequency of the parent clock, since
	 * it may be a parent for other peripherals. This is due to the fact
	 * that on Tegra20 there's only a single clock dedicated to display
	 * (pll_d_out0), whereas later generations have a second one that can
	 * be used to independently drive a second output (pll_d2_out0).
	 *
	 * As a way to support multiple outputs on Tegra20 as well, pll_p is
	 * typically used as the parent clock for the display controllers.
	 * But this comes at a cost: pll_p is the parent of several other
	 * peripherals, so its frequency shouldn't change out of the blue.
	 *
	 * The best we can do at this point is to use the shift clock divider
	 * and hope that the desired frequency can be matched (or at least
	 * matched sufficiently close that the panel will still work).
	 */

	*div = ((clk_get_rate(clk) * 2) / pclk) - 2;

	return 0;
}

static int tegra_output_rgb_check_mode(struct tegra_output *output,
				       struct drm_display_mode *mode,
				       enum drm_mode_status *status)
{
	/*
	 * FIXME: For now, always assume that the mode is okay. There are
	 * unresolved issues with clk_round_rate(), which doesn't always
	 * reliably report whether a frequency can be set or not.
	 */

	*status = MODE_OK;

	return 0;
}

static const struct tegra_output_ops rgb_ops = {
	.enable = tegra_output_rgb_enable,
	.disable = tegra_output_rgb_disable,
	.setup_clock = tegra_output_rgb_setup_clock,
	.check_mode = tegra_output_rgb_check_mode,
};

int tegra_dc_rgb_probe(struct tegra_dc *dc)
{
	struct device_node *np;
	struct tegra_rgb *rgb;
	int err;

	np = of_get_child_by_name(dc->dev->of_node, "rgb");
	if (!np || !of_device_is_available(np))
		return -ENODEV;

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

	rgb->output.dev = dc->dev;
	rgb->output.of_node = np;
	rgb->dc = dc;

	err = tegra_output_probe(&rgb->output);
	if (err < 0)
		return err;

	rgb->clk = devm_clk_get(dc->dev, NULL);
	if (IS_ERR(rgb->clk)) {
		dev_err(dc->dev, "failed to get clock\n");
		return PTR_ERR(rgb->clk);
	}

	rgb->clk_parent = devm_clk_get(dc->dev, "parent");
	if (IS_ERR(rgb->clk_parent)) {
		dev_err(dc->dev, "failed to get parent clock\n");
		return PTR_ERR(rgb->clk_parent);
	}

	err = clk_set_parent(rgb->clk, rgb->clk_parent);
	if (err < 0) {
		dev_err(dc->dev, "failed to set parent clock: %d\n", err);
		return err;
	}

	dc->rgb = &rgb->output;

	return 0;
}

int tegra_dc_rgb_remove(struct tegra_dc *dc)
{
	int err;

	if (!dc->rgb)
		return 0;

	err = tegra_output_remove(dc->rgb);
	if (err < 0)
		return err;

	return 0;
}

int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc)
{
	struct tegra_rgb *rgb = to_rgb(dc->rgb);
	int err;

	if (!dc->rgb)
		return -ENODEV;

	rgb->output.type = TEGRA_OUTPUT_RGB;
	rgb->output.ops = &rgb_ops;

	err = tegra_output_init(dc->base.dev, &rgb->output);
	if (err < 0) {
		dev_err(dc->dev, "output setup failed: %d\n", err);
		return err;
	}

	/*
	 * By default, outputs can be associated with each display controller.
	 * RGB outputs are an exception, so we make sure they can be attached
	 * to only their parent display controller.
	 */
	rgb->output.encoder.possible_crtcs = drm_crtc_mask(&dc->base);

	return 0;
}

int tegra_dc_rgb_exit(struct tegra_dc *dc)
{
	if (dc->rgb) {
		int err;

		err = tegra_output_disable(dc->rgb);
		if (err < 0) {
			dev_err(dc->dev, "output failed to disable: %d\n", err);
			return err;
		}

		err = tegra_output_exit(dc->rgb);
		if (err < 0) {
			dev_err(dc->dev, "output cleanup failed: %d\n", err);
			return err;
		}

		dc->rgb = NULL;
	}

	return 0;
}