// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright 2025 NXP
 * Based on panel-raspberrypi-touchscreen by Broadcom
 */

#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_graph.h>
#include <linux/regmap.h>

#include <drm/drm_bridge.h>
#include <drm/drm_mipi_dsi.h>
#include <drm/drm_of.h>
#include <drm/drm_panel.h>

struct ws_bridge {
        struct drm_bridge bridge;
        struct drm_bridge *next_bridge;
        struct backlight_device *backlight;
        struct device *dev;
        struct regmap *reg_map;
};

static const struct regmap_config ws_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .max_register = 0xff,
};

static struct ws_bridge *bridge_to_ws_bridge(struct drm_bridge *bridge)
{
        return container_of(bridge, struct ws_bridge, bridge);
}

static int ws_bridge_attach_dsi(struct ws_bridge *ws)
{
        const struct mipi_dsi_device_info info = {
                .type = "ws-bridge",
                .channel = 0,
                .node = NULL,
        };
        struct device_node *dsi_host_node;
        struct device *dev = ws->dev;
        struct mipi_dsi_device *dsi;
        struct mipi_dsi_host *host;
        int ret;

        dsi_host_node = of_graph_get_remote_node(dev->of_node, 0, 0);
        if (!dsi_host_node) {
                dev_err(dev, "Failed to get remote port\n");
                return -ENODEV;
        }
        host = of_find_mipi_dsi_host_by_node(dsi_host_node);
        of_node_put(dsi_host_node);
        if (!host)
                return dev_err_probe(dev, -EPROBE_DEFER, "Failed to find dsi_host\n");

        dsi = devm_mipi_dsi_device_register_full(dev, host, &info);
        if (IS_ERR(dsi))
                return dev_err_probe(dev, PTR_ERR(dsi), "Failed to create dsi device\n");

        dsi->mode_flags = MIPI_DSI_MODE_VIDEO_HSE | MIPI_DSI_MODE_VIDEO |
                          MIPI_DSI_CLOCK_NON_CONTINUOUS;
        dsi->format = MIPI_DSI_FMT_RGB888;
        dsi->lanes = 2;

        ret = devm_mipi_dsi_attach(dev, dsi);
        if (ret < 0)
                return dev_err_probe(dev, ret, "Failed to attach dsi to host\n");

        return 0;
}

static int ws_bridge_bridge_attach(struct drm_bridge *bridge,
                                   struct drm_encoder *encoder,
                                   enum drm_bridge_attach_flags flags)
{
        struct ws_bridge *ws = bridge_to_ws_bridge(bridge);
        int ret;

        ret = ws_bridge_attach_dsi(ws);
        if (ret)
                return ret;

        return drm_bridge_attach(encoder, ws->next_bridge,
                                 &ws->bridge, flags);
}

static void ws_bridge_bridge_enable(struct drm_bridge *bridge)
{
        struct ws_bridge *ws = bridge_to_ws_bridge(bridge);

        regmap_write(ws->reg_map, 0xad, 0x01);
        backlight_enable(ws->backlight);
}

static void ws_bridge_bridge_disable(struct drm_bridge *bridge)
{
        struct ws_bridge *ws = bridge_to_ws_bridge(bridge);

        backlight_disable(ws->backlight);
        regmap_write(ws->reg_map, 0xad, 0x00);
}

static const struct drm_bridge_funcs ws_bridge_bridge_funcs = {
        .enable = ws_bridge_bridge_enable,
        .disable = ws_bridge_bridge_disable,
        .attach = ws_bridge_bridge_attach,
};

static int ws_bridge_bl_update_status(struct backlight_device *bl)
{
        struct ws_bridge *ws = bl_get_data(bl);

        regmap_write(ws->reg_map, 0xab, 0xff - backlight_get_brightness(bl));
        regmap_write(ws->reg_map, 0xaa, 0x01);

        return 0;
}

static const struct backlight_ops ws_bridge_bl_ops = {
        .update_status = ws_bridge_bl_update_status,
};

static struct backlight_device *ws_bridge_create_backlight(struct ws_bridge *ws)
{
        const struct backlight_properties props = {
                .type = BACKLIGHT_RAW,
                .brightness = 255,
                .max_brightness = 255,
        };
        struct device *dev = ws->dev;

        return devm_backlight_device_register(dev, dev_name(dev), dev, ws,
                                              &ws_bridge_bl_ops, &props);
}

static int ws_bridge_probe(struct i2c_client *i2c)
{
        struct device *dev = &i2c->dev;
        struct drm_panel *panel;
        struct ws_bridge *ws;
        int ret;

        ws = devm_drm_bridge_alloc(dev, struct ws_bridge, bridge, &ws_bridge_bridge_funcs);
        if (IS_ERR(ws))
                return PTR_ERR(ws);

        ws->dev = dev;

        ws->reg_map = devm_regmap_init_i2c(i2c, &ws_regmap_config);
        if (IS_ERR(ws->reg_map))
                return dev_err_probe(dev, PTR_ERR(ws->reg_map), "Failed to allocate regmap\n");

        ret = drm_of_find_panel_or_bridge(dev->of_node, 1, -1, &panel, NULL);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to find remote panel\n");

        ws->next_bridge = devm_drm_panel_bridge_add(dev, panel);
        if (IS_ERR(ws->next_bridge))
                return PTR_ERR(ws->next_bridge);

        ws->backlight = ws_bridge_create_backlight(ws);
        if (IS_ERR(ws->backlight)) {
                ret = PTR_ERR(ws->backlight);
                dev_err(dev, "Failed to create backlight: %d\n", ret);
                return ret;
        }

        regmap_write(ws->reg_map, 0xc0, 0x01);
        regmap_write(ws->reg_map, 0xc2, 0x01);
        regmap_write(ws->reg_map, 0xac, 0x01);

        ws->bridge.type = DRM_MODE_CONNECTOR_DPI;
        ws->bridge.of_node = dev->of_node;
        devm_drm_bridge_add(dev, &ws->bridge);

        return 0;
}

static const struct of_device_id ws_bridge_of_ids[] = {
        {.compatible = "waveshare,dsi2dpi",},
        { }
};

MODULE_DEVICE_TABLE(of, ws_bridge_of_ids);

static struct i2c_driver ws_bridge_driver = {
        .driver = {
                .name = "ws_dsi2dpi",
                .of_match_table = ws_bridge_of_ids,
        },
        .probe = ws_bridge_probe,
};
module_i2c_driver(ws_bridge_driver);

MODULE_AUTHOR("Joseph Guo <qijian.guo@nxp.com>");
MODULE_DESCRIPTION("Waveshare DSI2DPI bridge driver");
MODULE_LICENSE("GPL");