// SPDX-License-Identifier: GPL-2.0+
/*
 * RZ/G2L Display Unit Encoder
 *
 * Copyright (C) 2023 Renesas Electronics Corporation
 *
 * Based on rcar_du_encoder.c
 */

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

#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_bridge_connector.h>
#include <drm/drm_panel.h>

#include "rzg2l_du_drv.h"
#include "rzg2l_du_encoder.h"

/* -----------------------------------------------------------------------------
 * Encoder
 */

static unsigned int rzg2l_du_encoder_count_ports(struct device_node *node)
{
        struct device_node *ports;
        struct device_node *port;
        unsigned int num_ports = 0;

        ports = of_get_child_by_name(node, "ports");
        if (!ports)
                ports = of_node_get(node);

        for_each_child_of_node(ports, port) {
                if (of_node_name_eq(port, "port"))
                        num_ports++;
        }

        of_node_put(ports);

        return num_ports;
}

static const struct drm_encoder_funcs rzg2l_du_encoder_funcs = {
};

static enum drm_mode_status
rzg2l_du_encoder_mode_valid(struct drm_encoder *encoder,
                            const struct drm_display_mode *mode)
{
        struct rzg2l_du_encoder *renc = to_rzg2l_encoder(encoder);

        if (renc->output == RZG2L_DU_OUTPUT_DPAD0 && mode->clock > 83500)
                return MODE_CLOCK_HIGH;

        return MODE_OK;
}

static const struct drm_encoder_helper_funcs rzg2l_du_encoder_helper_funcs = {
        .mode_valid = rzg2l_du_encoder_mode_valid,
};

int rzg2l_du_encoder_init(struct rzg2l_du_device  *rcdu,
                          enum rzg2l_du_output output,
                          struct device_node *enc_node)
{
        struct rzg2l_du_encoder *renc;
        struct drm_connector *connector;
        struct drm_bridge *bridge;
        int ret;

        /*
         * Locate the DRM bridge from the DT node. For the DPAD outputs, if the
         * DT node has a single port, assume that it describes a panel and
         * create a panel bridge.
         */
        if (output == RZG2L_DU_OUTPUT_DPAD0 && rzg2l_du_encoder_count_ports(enc_node) == 1) {
                struct drm_panel *panel = of_drm_find_panel(enc_node);

                if (IS_ERR(panel))
                        return PTR_ERR(panel);

                bridge = devm_drm_panel_bridge_add_typed(rcdu->dev, panel,
                                                         DRM_MODE_CONNECTOR_DPI);
                if (IS_ERR(bridge))
                        return PTR_ERR(bridge);
        } else {
                bridge = of_drm_find_bridge(enc_node);
                if (!bridge)
                        return -EPROBE_DEFER;
        }

        dev_dbg(rcdu->dev, "initializing encoder %pOF for output %s\n",
                enc_node, rzg2l_du_output_name(output));

        renc = drmm_encoder_alloc(&rcdu->ddev, struct rzg2l_du_encoder, base,
                                  &rzg2l_du_encoder_funcs, DRM_MODE_ENCODER_NONE,
                                  NULL);
        if (IS_ERR(renc))
                return PTR_ERR(renc);

        renc->output = output;
        drm_encoder_helper_add(&renc->base, &rzg2l_du_encoder_helper_funcs);

        /* Attach the bridge to the encoder. */
        ret = drm_bridge_attach(&renc->base, bridge, NULL,
                                DRM_BRIDGE_ATTACH_NO_CONNECTOR);
        if (ret) {
                dev_err(rcdu->dev,
                        "failed to attach bridge %pOF for output %s (%d)\n",
                        bridge->of_node, rzg2l_du_output_name(output), ret);
                return ret;
        }

        /* Create the connector for the chain of bridges. */
        connector = drm_bridge_connector_init(&rcdu->ddev, &renc->base);
        if (IS_ERR(connector)) {
                dev_err(rcdu->dev,
                        "failed to created connector for output %s (%ld)\n",
                        rzg2l_du_output_name(output), PTR_ERR(connector));
                return PTR_ERR(connector);
        }

        return drm_connector_attach_encoder(connector, &renc->base);
}