// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 Avionic Design GmbH
 * Copyright (C) 2012 NVIDIA CORPORATION.  All rights reserved.
 */

#include <linux/clk.h>
#include <linux/of.h>

#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge_connector.h>
#include <drm/drm_simple_kms_helper.h>

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

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

        struct clk *pll_d_out0;
        struct clk *pll_d2_out0;
        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 void tegra_rgb_encoder_disable(struct drm_encoder *encoder)
{
        struct tegra_output *output = encoder_to_output(encoder);
        struct tegra_rgb *rgb = to_rgb(output);

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

static void tegra_rgb_encoder_enable(struct drm_encoder *encoder)
{
        struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
        struct tegra_output *output = encoder_to_output(encoder);
        struct tegra_rgb *rgb = to_rgb(output);
        u32 value;

        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);

        /* configure H- and V-sync signal polarities */
        value = tegra_dc_readl(rgb->dc, DC_COM_PIN_OUTPUT_POLARITY(1));

        if (mode->flags & DRM_MODE_FLAG_NHSYNC)
                value |= LHS_OUTPUT_POLARITY_LOW;
        else
                value &= ~LHS_OUTPUT_POLARITY_LOW;

        if (mode->flags & DRM_MODE_FLAG_NVSYNC)
                value |= LVS_OUTPUT_POLARITY_LOW;
        else
                value &= ~LVS_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);

        tegra_dc_commit(rgb->dc);
}

static bool tegra_rgb_pll_rate_change_allowed(struct tegra_rgb *rgb)
{
        if (!rgb->pll_d2_out0)
                return false;

        if (!clk_is_match(rgb->clk_parent, rgb->pll_d_out0) &&
            !clk_is_match(rgb->clk_parent, rgb->pll_d2_out0))
                return false;

        return true;
}

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).
         */
        if (tegra_rgb_pll_rate_change_allowed(rgb)) {
                /*
                 * Set display controller clock to x2 of PCLK in order to
                 * produce higher resolution pulse positions.
                 */
                div = 2;
                pclk *= 2;
        } else {
                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,
};

static void tegra_dc_of_node_put(void *data)
{
        of_node_put(data);
}

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)
                return -ENODEV;

        err = devm_add_action_or_reset(dc->dev, tegra_dc_of_node_put, np);
        if (err < 0)
                return err;

        if (!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");
                err = PTR_ERR(rgb->clk);
                goto remove;
        }

        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");
                err = PTR_ERR(rgb->clk_parent);
                goto remove;
        }

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

        rgb->pll_d_out0 = clk_get_sys(NULL, "pll_d_out0");
        if (IS_ERR(rgb->pll_d_out0)) {
                err = PTR_ERR(rgb->pll_d_out0);
                dev_err(dc->dev, "failed to get pll_d_out0: %d\n", err);
                goto remove;
        }

        if (dc->soc->has_pll_d2_out0) {
                rgb->pll_d2_out0 = clk_get_sys(NULL, "pll_d2_out0");
                if (IS_ERR(rgb->pll_d2_out0)) {
                        err = PTR_ERR(rgb->pll_d2_out0);
                        dev_err(dc->dev, "failed to get pll_d2_out0: %d\n", err);
                        goto put_pll;
                }
        }

        dc->rgb = &rgb->output;

        return 0;

put_pll:
        clk_put(rgb->pll_d_out0);
remove:
        tegra_output_remove(&rgb->output);
        return err;
}

void tegra_dc_rgb_remove(struct tegra_dc *dc)
{
        struct tegra_rgb *rgb;

        if (!dc->rgb)
                return;

        rgb = to_rgb(dc->rgb);
        clk_put(rgb->pll_d2_out0);
        clk_put(rgb->pll_d_out0);

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

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

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

        drm_simple_encoder_init(drm, &output->encoder, DRM_MODE_ENCODER_LVDS);
        drm_encoder_helper_add(&output->encoder,
                               &tegra_rgb_encoder_helper_funcs);

        /*
         * Wrap directly-connected panel into DRM bridge in order to let
         * DRM core to handle panel for us.
         */
        if (output->panel) {
                output->bridge = devm_drm_panel_bridge_add(output->dev,
                                                           output->panel);
                if (IS_ERR(output->bridge)) {
                        dev_err(output->dev,
                                "failed to wrap panel into bridge: %pe\n",
                                output->bridge);
                        return PTR_ERR(output->bridge);
                }

                output->panel = NULL;
        }

        /*
         * Tegra devices that have LVDS panel utilize LVDS encoder bridge
         * for converting up to 28 LCD LVTTL lanes into 5/4 LVDS lanes that
         * go to display panel's receiver.
         *
         * Encoder usually have a power-down control which needs to be enabled
         * in order to transmit data to the panel.  Historically devices that
         * use an older device-tree version didn't model the bridge, assuming
         * that encoder is turned ON by default, while today's DRM allows us
         * to model LVDS encoder properly.
         *
         * Newer device-trees utilize LVDS encoder bridge, which provides
         * us with a connector and handles the display panel.
         *
         * For older device-trees we wrapped panel into the panel-bridge.
         */
        if (output->bridge) {
                err = drm_bridge_attach(&output->encoder, output->bridge,
                                        NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
                if (err)
                        return err;

                connector = drm_bridge_connector_init(drm, &output->encoder);
                if (IS_ERR(connector)) {
                        dev_err(output->dev,
                                "failed to initialize bridge connector: %pe\n",
                                connector);
                        return PTR_ERR(connector);
                }

                drm_connector_attach_encoder(connector, &output->encoder);
        }

        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;
}