// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2015 Free Electrons
 * Copyright (C) 2015 NextThing Co
 *
 * Maxime Ripard <maxime.ripard@free-electrons.com>
 */

#include <linux/clk.h>

#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_of.h>
#include <drm/drm_panel.h>
#include <drm/drm_print.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_simple_kms_helper.h>

#include "sun4i_crtc.h"
#include "sun4i_tcon.h"
#include "sun4i_rgb.h"

struct sun4i_rgb {
        struct drm_connector    connector;
        struct drm_encoder      encoder;

        struct sun4i_tcon       *tcon;
        struct drm_panel        *panel;
        struct drm_bridge       *bridge;
};

static inline struct sun4i_rgb *
drm_connector_to_sun4i_rgb(struct drm_connector *connector)
{
        return container_of(connector, struct sun4i_rgb,
                            connector);
}

static inline struct sun4i_rgb *
drm_encoder_to_sun4i_rgb(struct drm_encoder *encoder)
{
        return container_of(encoder, struct sun4i_rgb,
                            encoder);
}

static int sun4i_rgb_get_modes(struct drm_connector *connector)
{
        struct sun4i_rgb *rgb =
                drm_connector_to_sun4i_rgb(connector);

        return drm_panel_get_modes(rgb->panel, connector);
}

/*
 * VESA DMT defines a tolerance of 0.5% on the pixel clock, while the
 * CVT spec reuses that tolerance in its examples, so it looks to be a
 * good default tolerance for the EDID-based modes. Define it to 5 per
 * mille to avoid floating point operations.
 */
#define SUN4I_RGB_DOTCLOCK_TOLERANCE_PER_MILLE  5

static enum drm_mode_status sun4i_rgb_mode_valid(struct drm_encoder *crtc,
                                                 const struct drm_display_mode *mode)
{
        struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(crtc);
        struct sun4i_tcon *tcon = rgb->tcon;
        u32 hsync = mode->hsync_end - mode->hsync_start;
        u32 vsync = mode->vsync_end - mode->vsync_start;
        unsigned long long rate = mode->clock * 1000;
        unsigned long long lowest, highest;
        unsigned long long rounded_rate;

        DRM_DEBUG_DRIVER("Validating modes...\n");

        if (hsync < 1)
                return MODE_HSYNC_NARROW;

        if (hsync > 0x3ff)
                return MODE_HSYNC_WIDE;

        if ((mode->hdisplay < 1) || (mode->htotal < 1))
                return MODE_H_ILLEGAL;

        if ((mode->hdisplay > 0x7ff) || (mode->htotal > 0xfff))
                return MODE_BAD_HVALUE;

        DRM_DEBUG_DRIVER("Horizontal parameters OK\n");

        if (vsync < 1)
                return MODE_VSYNC_NARROW;

        if (vsync > 0x3ff)
                return MODE_VSYNC_WIDE;

        if ((mode->vdisplay < 1) || (mode->vtotal < 1))
                return MODE_V_ILLEGAL;

        if ((mode->vdisplay > 0x7ff) || (mode->vtotal > 0xfff))
                return MODE_BAD_VVALUE;

        DRM_DEBUG_DRIVER("Vertical parameters OK\n");

        /*
         * TODO: We should use the struct display_timing if available
         * and / or trying to stretch the timings within that
         * tolerancy to take care of panels that we wouldn't be able
         * to have a exact match for.
         */
        if (rgb->panel) {
                DRM_DEBUG_DRIVER("RGB panel used, skipping clock rate checks");
                goto out;
        }

        /*
         * That shouldn't ever happen unless something is really wrong, but it
         * doesn't harm to check.
         */
        if (!rgb->bridge)
                goto out;

        tcon->dclk_min_div = 6;
        tcon->dclk_max_div = 127;
        rounded_rate = clk_round_rate(tcon->dclk, rate);

        lowest = rate * (1000 - SUN4I_RGB_DOTCLOCK_TOLERANCE_PER_MILLE);
        do_div(lowest, 1000);
        if (rounded_rate < lowest)
                return MODE_CLOCK_LOW;

        highest = rate * (1000 + SUN4I_RGB_DOTCLOCK_TOLERANCE_PER_MILLE);
        do_div(highest, 1000);
        if (rounded_rate > highest)
                return MODE_CLOCK_HIGH;

out:
        DRM_DEBUG_DRIVER("Clock rate OK\n");

        return MODE_OK;
}

static const struct drm_connector_helper_funcs sun4i_rgb_con_helper_funcs = {
        .get_modes      = sun4i_rgb_get_modes,
};

static void
sun4i_rgb_connector_destroy(struct drm_connector *connector)
{
        drm_connector_cleanup(connector);
}

static const struct drm_connector_funcs sun4i_rgb_con_funcs = {
        .fill_modes             = drm_helper_probe_single_connector_modes,
        .destroy                = sun4i_rgb_connector_destroy,
        .reset                  = drm_atomic_helper_connector_reset,
        .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
        .atomic_destroy_state   = drm_atomic_helper_connector_destroy_state,
};

static void sun4i_rgb_encoder_enable(struct drm_encoder *encoder)
{
        struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(encoder);

        DRM_DEBUG_DRIVER("Enabling RGB output\n");

        if (rgb->panel) {
                drm_panel_prepare(rgb->panel);
                drm_panel_enable(rgb->panel);
        }
}

static void sun4i_rgb_encoder_disable(struct drm_encoder *encoder)
{
        struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(encoder);

        DRM_DEBUG_DRIVER("Disabling RGB output\n");

        if (rgb->panel) {
                drm_panel_disable(rgb->panel);
                drm_panel_unprepare(rgb->panel);
        }
}

static const struct drm_encoder_helper_funcs sun4i_rgb_enc_helper_funcs = {
        .disable        = sun4i_rgb_encoder_disable,
        .enable         = sun4i_rgb_encoder_enable,
        .mode_valid     = sun4i_rgb_mode_valid,
};

int sun4i_rgb_init(struct drm_device *drm, struct sun4i_tcon *tcon)
{
        struct drm_encoder *encoder;
        struct sun4i_rgb *rgb;
        int ret;

        rgb = devm_kzalloc(drm->dev, sizeof(*rgb), GFP_KERNEL);
        if (!rgb)
                return -ENOMEM;
        rgb->tcon = tcon;
        encoder = &rgb->encoder;

        ret = drm_of_find_panel_or_bridge(tcon->dev->of_node, 1, 0,
                                          &rgb->panel, &rgb->bridge);
        if (ret) {
                dev_info(drm->dev, "No panel or bridge found... RGB output disabled\n");
                return 0;
        }

        drm_encoder_helper_add(&rgb->encoder,
                               &sun4i_rgb_enc_helper_funcs);
        ret = drm_simple_encoder_init(drm, &rgb->encoder,
                                      DRM_MODE_ENCODER_NONE);
        if (ret) {
                dev_err(drm->dev, "Couldn't initialise the rgb encoder\n");
                goto err_out;
        }

        /* The RGB encoder can only work with the TCON channel 0 */
        rgb->encoder.possible_crtcs = drm_crtc_mask(&tcon->crtc->crtc);

        if (rgb->panel) {
                drm_connector_helper_add(&rgb->connector,
                                         &sun4i_rgb_con_helper_funcs);
                ret = drm_connector_init(drm, &rgb->connector,
                                         &sun4i_rgb_con_funcs,
                                         DRM_MODE_CONNECTOR_Unknown);
                if (ret) {
                        dev_err(drm->dev, "Couldn't initialise the rgb connector\n");
                        goto err_cleanup_connector;
                }

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

        if (rgb->bridge) {
                ret = drm_bridge_attach(encoder, rgb->bridge, NULL, 0);
                if (ret)
                        goto err_cleanup_connector;
        }

        return 0;

err_cleanup_connector:
        drm_encoder_cleanup(&rgb->encoder);
err_out:
        return ret;
}
EXPORT_SYMBOL(sun4i_rgb_init);