// SPDX-License-Identifier: GPL-2.0
/*
 * Synaptics TDDI display panel driver.
 *
 * Copyright (C) 2025 Kaustabh Chakraborty <kauschluss@disroot.org>
 */

#include <linux/backlight.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/regulator/consumer.h>

#include <video/mipi_display.h>

#include <drm/drm_mipi_dsi.h>
#include <drm/drm_modes.h>
#include <drm/drm_panel.h>
#include <drm/drm_probe_helper.h>

struct tddi_panel_data {
        u8 lanes;
        /* wait timings for panel enable */
        u8 delay_ms_sleep_exit;
        u8 delay_ms_display_on;
        /* wait timings for panel disable */
        u8 delay_ms_display_off;
        u8 delay_ms_sleep_enter;
};

struct tddi_ctx {
        struct drm_panel panel;
        struct mipi_dsi_device *dsi;
        struct drm_display_mode mode;
        struct backlight_device *backlight;
        const struct tddi_panel_data *data;
        struct regulator_bulk_data *supplies;
        struct gpio_desc *reset_gpio;
        struct gpio_desc *backlight_gpio;
};

static const struct regulator_bulk_data tddi_supplies[] = {
        { .supply = "vio" },
        { .supply = "vsn" },
        { .supply = "vsp" },
};

static inline struct tddi_ctx *to_tddi_ctx(struct drm_panel *panel)
{
        return container_of(panel, struct tddi_ctx, panel);
}

static int tddi_update_status(struct backlight_device *backlight)
{
        struct tddi_ctx *ctx = bl_get_data(backlight);
        struct mipi_dsi_multi_context dsi = { .dsi = ctx->dsi };
        u8 brightness = backlight_get_brightness(backlight);

        if (!ctx->panel.enabled)
                return 0;

        mipi_dsi_dcs_set_display_brightness_multi(&dsi, brightness);

        return dsi.accum_err;
}

static int tddi_prepare(struct drm_panel *panel)
{
        struct tddi_ctx *ctx = to_tddi_ctx(panel);
        struct device *dev = &ctx->dsi->dev;
        int ret;

        ret = regulator_bulk_enable(ARRAY_SIZE(tddi_supplies), ctx->supplies);
        if (ret < 0) {
                dev_err(dev, "failed to enable regulators: %d\n", ret);
                return ret;
        }

        gpiod_set_value_cansleep(ctx->reset_gpio, 0);
        usleep_range(5000, 6000);
        gpiod_set_value_cansleep(ctx->reset_gpio, 1);
        usleep_range(5000, 6000);
        gpiod_set_value_cansleep(ctx->reset_gpio, 0);
        usleep_range(10000, 11000);

        gpiod_set_value_cansleep(ctx->backlight_gpio, 0);
        usleep_range(5000, 6000);

        return 0;
}

static int tddi_unprepare(struct drm_panel *panel)
{
        struct tddi_ctx *ctx = to_tddi_ctx(panel);

        gpiod_set_value_cansleep(ctx->backlight_gpio, 1);
        usleep_range(5000, 6000);

        gpiod_set_value_cansleep(ctx->reset_gpio, 1);
        usleep_range(5000, 6000);

        regulator_bulk_disable(ARRAY_SIZE(tddi_supplies), ctx->supplies);

        return 0;
}

static int tddi_enable(struct drm_panel *panel)
{
        struct tddi_ctx *ctx = to_tddi_ctx(panel);
        struct mipi_dsi_multi_context dsi = { .dsi = ctx->dsi };
        u8 brightness = ctx->backlight->props.brightness;

        mipi_dsi_dcs_write_seq_multi(&dsi, MIPI_DCS_WRITE_POWER_SAVE, 0x00);
        mipi_dsi_dcs_write_seq_multi(&dsi, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x0c);

        mipi_dsi_dcs_exit_sleep_mode_multi(&dsi);
        mipi_dsi_msleep(&dsi, ctx->data->delay_ms_sleep_exit);

        /* sync the panel with the backlight's brightness level */
        mipi_dsi_dcs_set_display_brightness_multi(&dsi, brightness);

        mipi_dsi_dcs_set_display_on_multi(&dsi);
        mipi_dsi_msleep(&dsi, ctx->data->delay_ms_display_on);

        return dsi.accum_err;
};

static int tddi_disable(struct drm_panel *panel)
{
        struct tddi_ctx *ctx = to_tddi_ctx(panel);
        struct mipi_dsi_multi_context dsi = { .dsi = ctx->dsi };

        mipi_dsi_dcs_set_display_off_multi(&dsi);
        mipi_dsi_msleep(&dsi, ctx->data->delay_ms_display_off);

        mipi_dsi_dcs_enter_sleep_mode_multi(&dsi);
        mipi_dsi_msleep(&dsi, ctx->data->delay_ms_sleep_enter);

        return dsi.accum_err;
}

static int tddi_get_modes(struct drm_panel *panel,
                          struct drm_connector *connector)
{
        struct tddi_ctx *ctx = to_tddi_ctx(panel);

        return drm_connector_helper_get_modes_fixed(connector, &ctx->mode);
}

static const struct backlight_ops tddi_bl_ops = {
        .update_status = tddi_update_status,
};

static const struct backlight_properties tddi_bl_props = {
        .type = BACKLIGHT_PLATFORM,
        .brightness = 255,
        .max_brightness = 255,
};

static const struct drm_panel_funcs tddi_drm_panel_funcs = {
        .prepare = tddi_prepare,
        .unprepare = tddi_unprepare,
        .enable = tddi_enable,
        .disable = tddi_disable,
        .get_modes = tddi_get_modes,
};

static int tddi_probe(struct mipi_dsi_device *dsi)
{
        struct device *dev = &dsi->dev;
        struct tddi_ctx *ctx;
        int ret;

        ctx = devm_drm_panel_alloc(dev, struct tddi_ctx, panel,
                                   &tddi_drm_panel_funcs, DRM_MODE_CONNECTOR_DSI);
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);

        ctx->data = of_device_get_match_data(dev);

        ctx->dsi = dsi;
        mipi_dsi_set_drvdata(dsi, ctx);

        ret = devm_regulator_bulk_get_const(dev, ARRAY_SIZE(tddi_supplies),
                                            tddi_supplies, &ctx->supplies);
        if (ret < 0)
                return dev_err_probe(dev, ret, "failed to get regulators\n");

        ctx->backlight_gpio = devm_gpiod_get_optional(dev, "backlight", GPIOD_ASIS);
        if (IS_ERR(ctx->backlight_gpio))
                return dev_err_probe(dev, PTR_ERR(ctx->backlight_gpio),
                                     "failed to get backlight-gpios\n");

        ctx->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_ASIS);
        if (IS_ERR(ctx->reset_gpio))
                return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
                                     "failed to get reset-gpios\n");

        ret = of_get_drm_panel_display_mode(dev->of_node, &ctx->mode, NULL);
        if (ret < 0)
                return dev_err_probe(dev, ret, "failed to get panel timings\n");

        ctx->backlight = devm_backlight_device_register(dev, dev_name(dev), dev,
                                                        ctx, &tddi_bl_ops,
                                                        &tddi_bl_props);
        if (IS_ERR(ctx->backlight))
                return dev_err_probe(dev, PTR_ERR(ctx->backlight),
                                     "failed to register backlight device");

        dsi->lanes = ctx->data->lanes;
        dsi->format = MIPI_DSI_FMT_RGB888;
        dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
                          MIPI_DSI_MODE_VIDEO_NO_HFP;

        ctx->panel.prepare_prev_first = true;
        drm_panel_add(&ctx->panel);

        ret = devm_mipi_dsi_attach(dev, dsi);
        if (ret < 0) {
                drm_panel_remove(&ctx->panel);
                return dev_err_probe(dev, ret, "failed to attach to DSI host\n");
        }

        return 0;
}

static void tddi_remove(struct mipi_dsi_device *dsi)
{
        struct tddi_ctx *ctx = mipi_dsi_get_drvdata(dsi);

        drm_panel_remove(&ctx->panel);
}

static const struct tddi_panel_data td4101_panel_data = {
        .lanes = 2,
        /* wait timings for panel enable */
        .delay_ms_sleep_exit = 100,
        .delay_ms_display_on = 0,
        /* wait timings for panel disable */
        .delay_ms_display_off = 20,
        .delay_ms_sleep_enter = 90,
};

static const struct tddi_panel_data td4300_panel_data = {
        .lanes = 4,
        /* wait timings for panel enable */
        .delay_ms_sleep_exit = 100,
        .delay_ms_display_on = 0,
        /* wait timings for panel disable */
        .delay_ms_display_off = 0,
        .delay_ms_sleep_enter = 0,
};

static const struct of_device_id tddi_of_device_id[] = {
        {
                .compatible = "syna,td4101-panel",
                .data = &td4101_panel_data,
        }, {
                .compatible = "syna,td4300-panel",
                .data = &td4300_panel_data,
        }, { }
};
MODULE_DEVICE_TABLE(of, tddi_of_device_id);

static struct mipi_dsi_driver tddi_dsi_driver = {
        .probe = tddi_probe,
        .remove = tddi_remove,
        .driver = {
                .name = "panel-synaptics-tddi",
                .of_match_table = tddi_of_device_id,
        },
};
module_mipi_dsi_driver(tddi_dsi_driver);

MODULE_AUTHOR("Kaustabh Chakraborty <kauschluss@disroot.org>");
MODULE_DESCRIPTION("Synaptics TDDI Display Panel Driver");
MODULE_LICENSE("GPL");