/*
 * 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/drm_atomic_helper.h>
#include <drm/drm_panel.h>

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

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

        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 const struct drm_connector_funcs tegra_rgb_connector_funcs = {
        .dpms = drm_atomic_helper_connector_dpms,
        .reset = drm_atomic_helper_connector_reset,
        .detect = tegra_output_connector_detect,
        .fill_modes = drm_helper_probe_single_connector_modes,
        .destroy = tegra_output_connector_destroy,
        .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
        .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
};

static enum drm_mode_status
tegra_rgb_connector_mode_valid(struct drm_connector *connector,
                               struct drm_display_mode *mode)
{
        /*
         * 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.
         */
        return MODE_OK;
}

static const struct drm_connector_helper_funcs tegra_rgb_connector_helper_funcs = {
        .get_modes = tegra_output_connector_get_modes,
        .mode_valid = tegra_rgb_connector_mode_valid,
        .best_encoder = tegra_output_connector_best_encoder,
};

static const struct drm_encoder_funcs tegra_rgb_encoder_funcs = {
        .destroy = tegra_output_encoder_destroy,
};

static void tegra_rgb_encoder_disable(struct drm_encoder *encoder)
{
        struct tegra_output *output = encoder_to_output(encoder);
        struct tegra_rgb *rgb = to_rgb(output);

        if (output->panel)
                drm_panel_disable(output->panel);

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

        if (output->panel)
                drm_panel_unprepare(output->panel);
}

static void tegra_rgb_encoder_enable(struct drm_encoder *encoder)
{
        struct tegra_output *output = encoder_to_output(encoder);
        struct tegra_rgb *rgb = to_rgb(output);
        u32 value;

        if (output->panel)
                drm_panel_prepare(output->panel);

        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);

        tegra_dc_commit(rgb->dc);

        if (output->panel)
                drm_panel_enable(output->panel);
}

static int
tegra_rgb_encoder_atomic_check(struct drm_encoder *encoder,
                               struct drm_crtc_state *crtc_state,
                               struct drm_connector_state *conn_state)
{
        struct tegra_output *output = encoder_to_output(encoder);
        struct tegra_dc *dc = to_tegra_dc(conn_state->crtc);
        unsigned long pclk = crtc_state->mode.clock * 1000;
        struct tegra_rgb *rgb = to_rgb(output);
        unsigned int div;
        int 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(rgb->clk) * 2) / pclk) - 2;
        pclk = 0;

        err = tegra_dc_state_setup_clock(dc, crtc_state, rgb->clk_parent,
                                         pclk, div);
        if (err < 0) {
                dev_err(output->dev, "failed to setup CRTC state: %d\n", err);
                return err;
        }

        return err;
}

static const struct drm_encoder_helper_funcs tegra_rgb_encoder_helper_funcs = {
        .disable = tegra_rgb_encoder_disable,
        .enable = tegra_rgb_encoder_enable,
        .atomic_check = tegra_rgb_encoder_atomic_check,
};

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)
{
        if (!dc->rgb)
                return 0;

        tegra_output_remove(dc->rgb);
        dc->rgb = NULL;

        return 0;
}

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

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

        drm_connector_init(drm, &output->connector, &tegra_rgb_connector_funcs,
                           DRM_MODE_CONNECTOR_LVDS);
        drm_connector_helper_add(&output->connector,
                                 &tegra_rgb_connector_helper_funcs);
        output->connector.dpms = DRM_MODE_DPMS_OFF;

        drm_encoder_init(drm, &output->encoder, &tegra_rgb_encoder_funcs,
                         DRM_MODE_ENCODER_LVDS, NULL);
        drm_encoder_helper_add(&output->encoder,
                               &tegra_rgb_encoder_helper_funcs);

        drm_mode_connector_attach_encoder(&output->connector,
                                          &output->encoder);
        drm_connector_register(&output->connector);

        err = tegra_output_init(drm, output);
        if (err < 0) {
                dev_err(output->dev, "failed to initialize output: %d\n", err);
                return err;
        }

        /*
         * Other outputs can be attached to either display controller. The RGB
         * outputs are an exception and work only with their parent display
         * controller.
         */
        output->encoder.possible_crtcs = drm_crtc_mask(&dc->base);

        return 0;
}

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

        return 0;
}