/*
 * Copyright © 2015 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */

/*
 * Laptops with Intel GPUs which have panels that support controlling the
 * backlight through DP AUX can actually use two different interfaces: Intel's
 * proprietary DP AUX backlight interface, and the standard VESA backlight
 * interface. Unfortunately, at the time of writing this a lot of laptops will
 * advertise support for the standard VESA backlight interface when they
 * don't properly support it. However, on these systems the Intel backlight
 * interface generally does work properly. Additionally, these systems will
 * usually just indicate that they use PWM backlight controls in their VBIOS
 * for some reason.
 */

#include <drm/drm_print.h>

#include <linux/kconfig.h>
#include "intel_backlight.h"
#include "intel_display_core.h"
#include "intel_display_types.h"
#include "intel_dp.h"
#include "intel_dp_aux_backlight.h"

/*
 * DP AUX registers for Intel's proprietary HDR backlight interface. We define
 * them here since we'll likely be the only driver to ever use these.
 */
#define INTEL_EDP_HDR_TCON_CAP0                                        0x340

#define INTEL_EDP_HDR_TCON_CAP1                                        0x341
# define INTEL_EDP_HDR_TCON_2084_DECODE_CAP                           BIT(0)
# define INTEL_EDP_HDR_TCON_2020_GAMUT_CAP                            BIT(1)
# define INTEL_EDP_HDR_TCON_TONE_MAPPING_CAP                          BIT(2)
# define INTEL_EDP_HDR_TCON_SEGMENTED_BACKLIGHT_CAP                   BIT(3)
# define INTEL_EDP_HDR_TCON_BRIGHTNESS_NITS_CAP                       BIT(4)
# define INTEL_EDP_HDR_TCON_OPTIMIZATION_CAP                          BIT(5)
# define INTEL_EDP_HDR_TCON_SDP_COLORIMETRY_CAP                       BIT(6)
# define INTEL_EDP_HDR_TCON_SRGB_TO_PANEL_GAMUT_CONVERSION_CAP        BIT(7)

#define INTEL_EDP_HDR_TCON_CAP2                                        0x342
# define INTEL_EDP_SDR_TCON_BRIGHTNESS_AUX_CAP                        BIT(0)

#define INTEL_EDP_HDR_TCON_CAP3                                        0x343

#define INTEL_EDP_HDR_GETSET_CTRL_PARAMS                               0x344
# define INTEL_EDP_HDR_TCON_2084_DECODE_ENABLE                        BIT(0)
# define INTEL_EDP_HDR_TCON_2020_GAMUT_ENABLE                         BIT(1)
# define INTEL_EDP_HDR_TCON_TONE_MAPPING_ENABLE                       BIT(2)
# define INTEL_EDP_HDR_TCON_SEGMENTED_BACKLIGHT_ENABLE                BIT(3)
# define INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE                     BIT(4)
# define INTEL_EDP_HDR_TCON_SRGB_TO_PANEL_GAMUT_ENABLE                BIT(5)
/* Bit 6 is reserved */
# define INTEL_EDP_HDR_TCON_SDP_OVERRIDE_AUX                          BIT(7)

#define INTEL_EDP_HDR_CONTENT_LUMINANCE                                0x346
#define INTEL_EDP_HDR_PANEL_LUMINANCE_OVERRIDE                         0x34A
#define INTEL_EDP_SDR_LUMINANCE_LEVEL                                  0x352
#define INTEL_EDP_BRIGHTNESS_NITS_LSB                                  0x354
#define INTEL_EDP_BRIGHTNESS_NITS_MSB                                  0x355
#define INTEL_EDP_BRIGHTNESS_DELAY_FRAMES                              0x356
#define INTEL_EDP_BRIGHTNESS_PER_FRAME_STEPS                           0x357

#define INTEL_EDP_BRIGHTNESS_OPTIMIZATION_0                            0x358
# define INTEL_EDP_TCON_USAGE_MASK                             GENMASK(0, 3)
# define INTEL_EDP_TCON_USAGE_UNKNOWN                                    0x0
# define INTEL_EDP_TCON_USAGE_DESKTOP                                    0x1
# define INTEL_EDP_TCON_USAGE_FULL_SCREEN_MEDIA                          0x2
# define INTEL_EDP_TCON_USAGE_FULL_SCREEN_GAMING                         0x3
# define INTEL_EDP_TCON_POWER_MASK                                    BIT(4)
# define INTEL_EDP_TCON_POWER_DC                                    (0 << 4)
# define INTEL_EDP_TCON_POWER_AC                                    (1 << 4)
# define INTEL_EDP_TCON_OPTIMIZATION_STRENGTH_MASK             GENMASK(5, 7)

#define INTEL_EDP_BRIGHTNESS_OPTIMIZATION_1                            0x359

enum intel_dp_aux_backlight_modparam {
        INTEL_DP_AUX_BACKLIGHT_AUTO = -1,
        INTEL_DP_AUX_BACKLIGHT_OFF = 0,
        INTEL_DP_AUX_BACKLIGHT_ON = 1,
        INTEL_DP_AUX_BACKLIGHT_FORCE_VESA = 2,
        INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL = 3,
};

static bool is_intel_tcon_cap(const u8 tcon_cap[4])
{
        return tcon_cap[0] >= 1;
}

/* Intel EDP backlight callbacks */
static bool
intel_dp_aux_supports_hdr_backlight(struct intel_connector *connector)
{
        struct intel_display *display = to_intel_display(connector);
        struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
        struct drm_dp_aux *aux = &intel_dp->aux;
        struct intel_panel *panel = &connector->panel;
        int ret;
        u8 tcon_cap[4];

        intel_dp_wait_source_oui(intel_dp);

        ret = drm_dp_dpcd_read(aux, INTEL_EDP_HDR_TCON_CAP0, tcon_cap, sizeof(tcon_cap));
        if (ret != sizeof(tcon_cap))
                return false;

        drm_dbg_kms(display->drm,
                    "[CONNECTOR:%d:%s] Detected %s HDR backlight interface version %d\n",
                    connector->base.base.id, connector->base.name,
                    is_intel_tcon_cap(tcon_cap) ? "Intel" : "unsupported", tcon_cap[0]);

        if (!is_intel_tcon_cap(tcon_cap))
                return false;

        if (!(tcon_cap[1] & INTEL_EDP_HDR_TCON_BRIGHTNESS_NITS_CAP))
                return false;

        /*
         * If we don't have HDR static metadata there is no way to
         * runtime detect used range for nits based control. For now
         * do not use Intel proprietary eDP backlight control if we
         * don't have this data in panel EDID. In case we find panel
         * which supports only nits based control, but doesn't provide
         * HDR static metadata we need to start maintaining table of
         * ranges for such panels.
         */
        if (display->params.enable_dpcd_backlight != INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL &&
            !(connector->base.display_info.hdr_sink_metadata.hdmi_type1.metadata_type &
              BIT(HDMI_STATIC_METADATA_TYPE1))) {
                drm_info(display->drm,
                         "[CONNECTOR:%d:%s] Panel is missing HDR static metadata. Possible support for Intel HDR backlight interface is not used. If your backlight controls don't work try booting with i915.enable_dpcd_backlight=%d.\n",
                         connector->base.base.id, connector->base.name,
                         INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL);
                return false;
        }

        panel->backlight.edp.intel_cap.sdr_uses_aux =
                tcon_cap[2] & INTEL_EDP_SDR_TCON_BRIGHTNESS_AUX_CAP;
        panel->backlight.edp.intel_cap.supports_2084_decode =
                tcon_cap[1] & INTEL_EDP_HDR_TCON_2084_DECODE_CAP;
        panel->backlight.edp.intel_cap.supports_2020_gamut =
                tcon_cap[1] & INTEL_EDP_HDR_TCON_2020_GAMUT_CAP;
        panel->backlight.edp.intel_cap.supports_segmented_backlight =
                tcon_cap[1] & INTEL_EDP_HDR_TCON_SEGMENTED_BACKLIGHT_CAP;
        panel->backlight.edp.intel_cap.supports_sdp_colorimetry =
                tcon_cap[1] & INTEL_EDP_HDR_TCON_SDP_COLORIMETRY_CAP;
        panel->backlight.edp.intel_cap.supports_tone_mapping =
                tcon_cap[1] & INTEL_EDP_HDR_TCON_TONE_MAPPING_CAP;

        return true;
}

static u32
intel_dp_aux_hdr_get_backlight(struct intel_connector *connector, enum pipe pipe)
{
        struct intel_display *display = to_intel_display(connector);
        struct intel_panel *panel = &connector->panel;
        struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
        u8 tmp;
        u8 buf[2] = {};

        if (drm_dp_dpcd_readb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, &tmp) != 1) {
                drm_err(display->drm,
                        "[CONNECTOR:%d:%s] Failed to read current backlight mode from DPCD\n",
                        connector->base.base.id, connector->base.name);
                return 0;
        }

        if (!(tmp & INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE)) {
                if (!panel->backlight.edp.intel_cap.sdr_uses_aux) {
                        u32 pwm_level = panel->backlight.pwm_funcs->get(connector, pipe);

                        return intel_backlight_level_from_pwm(connector, pwm_level);
                }

                /* Assume 100% brightness if backlight controls aren't enabled yet */
                return panel->backlight.max;
        }

        if (drm_dp_dpcd_read(&intel_dp->aux, INTEL_EDP_BRIGHTNESS_NITS_LSB, buf,
                             sizeof(buf)) != sizeof(buf)) {
                drm_err(display->drm,
                        "[CONNECTOR:%d:%s] Failed to read brightness from DPCD\n",
                        connector->base.base.id, connector->base.name);
                return 0;
        }

        return (buf[1] << 8 | buf[0]);
}

static void
intel_dp_aux_hdr_set_aux_backlight(const struct drm_connector_state *conn_state, u32 level)
{
        struct intel_connector *connector = to_intel_connector(conn_state->connector);
        struct drm_device *dev = connector->base.dev;
        struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
        u8 buf[4] = {};

        buf[0] = level & 0xFF;
        buf[1] = (level & 0xFF00) >> 8;

        if (drm_dp_dpcd_write(&intel_dp->aux, INTEL_EDP_BRIGHTNESS_NITS_LSB, buf,
                              sizeof(buf)) != sizeof(buf))
                drm_err(dev, "[CONNECTOR:%d:%s] Failed to write brightness level to DPCD\n",
                        connector->base.base.id, connector->base.name);
}

static void
intel_dp_aux_hdr_set_backlight(const struct drm_connector_state *conn_state, u32 level)
{
        struct intel_connector *connector = to_intel_connector(conn_state->connector);
        struct intel_panel *panel = &connector->panel;

        if (intel_dp_in_hdr_mode(conn_state) ||
            panel->backlight.edp.intel_cap.sdr_uses_aux) {
                intel_dp_aux_hdr_set_aux_backlight(conn_state, level);
        } else {
                const u32 pwm_level = intel_backlight_level_to_pwm(connector, level);

                intel_backlight_set_pwm_level(conn_state, pwm_level);
        }
}

static void
intel_dp_aux_write_content_luminance(struct intel_connector *connector,
                                     struct hdr_output_metadata *hdr_metadata)
{
        struct intel_display *display = to_intel_display(connector);
        struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
        int ret;
        u8 buf[4];

        if (!intel_dp_has_gamut_metadata_dip(connector->encoder))
                return;

        buf[0] = hdr_metadata->hdmi_metadata_type1.max_cll & 0xFF;
        buf[1] = (hdr_metadata->hdmi_metadata_type1.max_cll & 0xFF00) >> 8;
        buf[2] = hdr_metadata->hdmi_metadata_type1.max_fall & 0xFF;
        buf[3] = (hdr_metadata->hdmi_metadata_type1.max_fall & 0xFF00) >> 8;

        ret = drm_dp_dpcd_write(&intel_dp->aux,
                                INTEL_EDP_HDR_CONTENT_LUMINANCE,
                                buf, sizeof(buf));
        if (ret < 0)
                drm_dbg_kms(display->drm,
                            "Content Luminance DPCD reg write failed, err:-%d\n",
                            ret);
}

static void
intel_dp_aux_fill_hdr_tcon_params(const struct drm_connector_state *conn_state, u8 *ctrl)
{
        struct intel_connector *connector = to_intel_connector(conn_state->connector);
        struct intel_panel *panel = &connector->panel;
        struct intel_display *display = to_intel_display(connector);

        /*
         * According to spec segmented backlight needs to be set whenever panel is in
         * HDR mode.
         */
        if (intel_dp_in_hdr_mode(conn_state)) {
                *ctrl |= INTEL_EDP_HDR_TCON_SEGMENTED_BACKLIGHT_ENABLE;
                *ctrl |= INTEL_EDP_HDR_TCON_2084_DECODE_ENABLE;
        }

        if (DISPLAY_VER(display) < 11)
                *ctrl &= ~INTEL_EDP_HDR_TCON_TONE_MAPPING_ENABLE;

        if (panel->backlight.edp.intel_cap.supports_2020_gamut &&
            (conn_state->colorspace == DRM_MODE_COLORIMETRY_BT2020_RGB ||
             conn_state->colorspace == DRM_MODE_COLORIMETRY_BT2020_YCC ||
             conn_state->colorspace == DRM_MODE_COLORIMETRY_BT2020_CYCC))
                *ctrl |= INTEL_EDP_HDR_TCON_2020_GAMUT_ENABLE;

        if (panel->backlight.edp.intel_cap.supports_sdp_colorimetry &&
            intel_dp_has_gamut_metadata_dip(connector->encoder))
                *ctrl |= INTEL_EDP_HDR_TCON_SDP_OVERRIDE_AUX;
        else
                *ctrl &= ~INTEL_EDP_HDR_TCON_SDP_OVERRIDE_AUX;
}

static void
intel_dp_aux_hdr_enable_backlight(const struct intel_crtc_state *crtc_state,
                                  const struct drm_connector_state *conn_state, u32 level)
{
        struct intel_display *display = to_intel_display(crtc_state);
        struct intel_connector *connector = to_intel_connector(conn_state->connector);
        struct intel_panel *panel = &connector->panel;
        struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
        struct hdr_output_metadata *hdr_metadata;
        int ret;
        u8 old_ctrl, ctrl;

        intel_dp_wait_source_oui(intel_dp);

        ret = drm_dp_dpcd_readb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, &old_ctrl);
        if (ret != 1) {
                drm_err(display->drm,
                        "[CONNECTOR:%d:%s] Failed to read current backlight control mode: %d\n",
                        connector->base.base.id, connector->base.name, ret);
                return;
        }

        ctrl = old_ctrl;
        if (intel_dp_in_hdr_mode(conn_state) ||
            panel->backlight.edp.intel_cap.sdr_uses_aux) {
                ctrl |= INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE;

                intel_dp_aux_hdr_set_aux_backlight(conn_state, level);
        } else {
                u32 pwm_level = intel_backlight_level_to_pwm(connector, level);

                panel->backlight.pwm_funcs->enable(crtc_state, conn_state, pwm_level);

                ctrl &= ~INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE;
        }

        intel_dp_aux_fill_hdr_tcon_params(conn_state, &ctrl);

        if (ctrl != old_ctrl &&
            drm_dp_dpcd_writeb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, ctrl) != 1)
                drm_err(display->drm,
                        "[CONNECTOR:%d:%s] Failed to configure DPCD brightness controls\n",
                        connector->base.base.id, connector->base.name);

        if (intel_dp_in_hdr_mode(conn_state)) {
                hdr_metadata = conn_state->hdr_output_metadata->data;
                intel_dp_aux_write_content_luminance(connector, hdr_metadata);
        }
}

static void
intel_dp_aux_hdr_disable_backlight(const struct drm_connector_state *conn_state, u32 level)
{
        struct intel_connector *connector = to_intel_connector(conn_state->connector);
        struct intel_panel *panel = &connector->panel;

        /* Nothing to do for AUX based backlight controls */
        if (panel->backlight.edp.intel_cap.sdr_uses_aux)
                return;

        /* Note we want the actual pwm_level to be 0, regardless of pwm_min */
        panel->backlight.pwm_funcs->disable(conn_state, intel_backlight_invert_pwm_level(connector, 0));
}

static const char *dpcd_vs_pwm_str(bool aux)
{
        return aux ? "DPCD" : "PWM";
}

static void
intel_dp_aux_write_panel_luminance_override(struct intel_connector *connector)
{
        struct intel_display *display = to_intel_display(connector);
        struct intel_panel *panel = &connector->panel;
        struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
        int ret;
        u8 buf[4] = {};

        buf[0] = panel->backlight.min & 0xFF;
        buf[1] = (panel->backlight.min & 0xFF00) >> 8;
        buf[2] = panel->backlight.max & 0xFF;
        buf[3] = (panel->backlight.max & 0xFF00) >> 8;

        ret = drm_dp_dpcd_write(&intel_dp->aux,
                                INTEL_EDP_HDR_PANEL_LUMINANCE_OVERRIDE,
                                buf, sizeof(buf));
        if (ret < 0)
                drm_dbg_kms(display->drm,
                            "Panel Luminance DPCD reg write failed, err:-%d\n",
                            ret);
}

static int
intel_dp_aux_hdr_setup_backlight(struct intel_connector *connector, enum pipe pipe)
{
        struct intel_display *display = to_intel_display(connector);
        struct intel_panel *panel = &connector->panel;
        struct drm_luminance_range_info *luminance_range =
                &connector->base.display_info.luminance_range;
        int ret;

        drm_dbg_kms(display->drm,
                    "[CONNECTOR:%d:%s] SDR backlight is controlled through %s\n",
                    connector->base.base.id, connector->base.name,
                    dpcd_vs_pwm_str(panel->backlight.edp.intel_cap.sdr_uses_aux));

        if (!panel->backlight.edp.intel_cap.sdr_uses_aux) {
                ret = panel->backlight.pwm_funcs->setup(connector, pipe);
                if (ret < 0) {
                        drm_err(display->drm,
                                "[CONNECTOR:%d:%s] Failed to setup SDR backlight controls through PWM: %d\n",
                                connector->base.base.id, connector->base.name, ret);
                        return ret;
                }
        }

        if (luminance_range->max_luminance) {
                panel->backlight.max = luminance_range->max_luminance;
                panel->backlight.min = luminance_range->min_luminance;
        } else {
                panel->backlight.max = 512;
                panel->backlight.min = 0;
        }

        intel_dp_aux_write_panel_luminance_override(connector);

        drm_dbg_kms(display->drm,
                    "[CONNECTOR:%d:%s] Using AUX HDR interface for backlight control (range %d..%d)\n",
                    connector->base.base.id, connector->base.name,
                    panel->backlight.min, panel->backlight.max);

        panel->backlight.level = intel_dp_aux_hdr_get_backlight(connector, pipe);
        panel->backlight.enabled = panel->backlight.level != 0;

        return 0;
}

/* VESA backlight callbacks */
static u32 intel_dp_aux_vesa_get_backlight(struct intel_connector *connector, enum pipe unused)
{
        struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
        struct intel_panel *panel = &connector->panel;
        u8 buf[3];
        u32 val = 0;
        int ret;

        if (panel->backlight.edp.vesa.luminance_control_support) {
                ret = drm_dp_dpcd_read(&intel_dp->aux, DP_EDP_PANEL_TARGET_LUMINANCE_VALUE, buf,
                                       sizeof(buf));
                if (ret < 0) {
                        drm_err(intel_dp->aux.drm_dev,
                                "[CONNECTOR:%d:%s] Failed to read Luminance from DPCD\n",
                                connector->base.base.id, connector->base.name);
                        return 0;
                }

                val |= buf[0] | buf[1] << 8 | buf[2] << 16;
                return val / 1000;
        }

        return connector->panel.backlight.level;
}

static void
intel_dp_aux_vesa_set_backlight(const struct drm_connector_state *conn_state, u32 level)
{
        struct intel_connector *connector = to_intel_connector(conn_state->connector);
        struct intel_panel *panel = &connector->panel;
        struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);

        if (!panel->backlight.edp.vesa.info.aux_set) {
                const u32 pwm_level = intel_backlight_level_to_pwm(connector, level);

                intel_backlight_set_pwm_level(conn_state, pwm_level);
        }

        drm_edp_backlight_set_level(&intel_dp->aux, &panel->backlight.edp.vesa.info, level);
}

static void
intel_dp_aux_vesa_enable_backlight(const struct intel_crtc_state *crtc_state,
                                   const struct drm_connector_state *conn_state, u32 level)
{
        struct intel_connector *connector = to_intel_connector(conn_state->connector);
        struct intel_panel *panel = &connector->panel;
        struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);

        if (!panel->backlight.edp.vesa.info.aux_enable) {
                u32 pwm_level;

                if (!panel->backlight.edp.vesa.info.aux_set)
                        pwm_level = intel_backlight_level_to_pwm(connector, level);
                else
                        pwm_level = intel_backlight_invert_pwm_level(connector,
                                                                     panel->backlight.pwm_level_max);

                panel->backlight.pwm_funcs->enable(crtc_state, conn_state, pwm_level);
        }

        drm_edp_backlight_enable(&intel_dp->aux, &panel->backlight.edp.vesa.info, level);
}

static void intel_dp_aux_vesa_disable_backlight(const struct drm_connector_state *old_conn_state,
                                                u32 level)
{
        struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
        struct intel_panel *panel = &connector->panel;
        struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);

        drm_edp_backlight_disable(&intel_dp->aux, &panel->backlight.edp.vesa.info);

        if (!panel->backlight.edp.vesa.info.aux_enable)
                panel->backlight.pwm_funcs->disable(old_conn_state,
                                                    intel_backlight_invert_pwm_level(connector, 0));
}

static int intel_dp_aux_vesa_setup_backlight(struct intel_connector *connector, enum pipe pipe)
{
        struct intel_display *display = to_intel_display(connector);
        struct drm_luminance_range_info *luminance_range =
                &connector->base.display_info.luminance_range;
        struct intel_dp *intel_dp = intel_attached_dp(connector);
        struct intel_panel *panel = &connector->panel;
        u32 current_level;
        u8 current_mode;
        int ret;

        ret = drm_edp_backlight_init(&intel_dp->aux, &panel->backlight.edp.vesa.info,
                                     luminance_range->max_luminance,
                                     panel->vbt.backlight.pwm_freq_hz,
                                     intel_dp->edp_dpcd, &current_level, &current_mode,
                                     panel->backlight.edp.vesa.luminance_control_support);
        if (ret < 0)
                return ret;

        drm_dbg_kms(display->drm,
                    "[CONNECTOR:%d:%s] AUX VESA backlight enable is controlled through %s\n",
                    connector->base.base.id, connector->base.name,
                    dpcd_vs_pwm_str(panel->backlight.edp.vesa.info.aux_enable));
        drm_dbg_kms(display->drm,
                    "[CONNECTOR:%d:%s] AUX VESA backlight level is controlled through %s\n",
                    connector->base.base.id, connector->base.name,
                    dpcd_vs_pwm_str(panel->backlight.edp.vesa.info.aux_set));

        if (!panel->backlight.edp.vesa.info.aux_set ||
            !panel->backlight.edp.vesa.info.aux_enable) {
                ret = panel->backlight.pwm_funcs->setup(connector, pipe);
                if (ret < 0) {
                        drm_err(display->drm,
                                "[CONNECTOR:%d:%s] Failed to setup PWM backlight controls for eDP backlight: %d\n",
                                connector->base.base.id, connector->base.name, ret);
                        return ret;
                }
        }

        if (panel->backlight.edp.vesa.info.luminance_set) {
                if (luminance_range->max_luminance) {
                        panel->backlight.max = panel->backlight.edp.vesa.info.max;
                        panel->backlight.min = luminance_range->min_luminance;
                } else {
                        panel->backlight.max = 512;
                        panel->backlight.min = 0;
                }
                panel->backlight.level = intel_dp_aux_vesa_get_backlight(connector, 0);
                panel->backlight.enabled = panel->backlight.level != 0;
                drm_dbg_kms(display->drm,
                            "[CONNECTOR:%d:%s] AUX VESA Nits backlight level is controlled through DPCD\n",
                            connector->base.base.id, connector->base.name);
        } else if (panel->backlight.edp.vesa.info.aux_set) {
                panel->backlight.max = panel->backlight.edp.vesa.info.max;
                panel->backlight.min = 0;
                if (current_mode == DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD) {
                        panel->backlight.level = current_level;
                        panel->backlight.enabled = panel->backlight.level != 0;
                } else {
                        panel->backlight.level = panel->backlight.max;
                        panel->backlight.enabled = false;
                }
        } else {
                panel->backlight.max = panel->backlight.pwm_level_max;
                panel->backlight.min = panel->backlight.pwm_level_min;
                if (current_mode == DP_EDP_BACKLIGHT_CONTROL_MODE_PWM) {
                        panel->backlight.level =
                                panel->backlight.pwm_funcs->get(connector, pipe);
                        panel->backlight.enabled = panel->backlight.pwm_enabled;
                } else {
                        panel->backlight.level = panel->backlight.max;
                        panel->backlight.enabled = false;
                }
        }

        drm_dbg_kms(display->drm,
                    "[CONNECTOR:%d:%s] Using AUX VESA interface for backlight control\n",
                    connector->base.base.id, connector->base.name);

        return 0;
}

static bool
intel_dp_aux_supports_vesa_backlight(struct intel_connector *connector)
{
        struct intel_display *display = to_intel_display(connector);
        struct intel_dp *intel_dp = intel_attached_dp(connector);
        struct intel_panel *panel = &connector->panel;

        if ((intel_dp->edp_dpcd[3] & DP_EDP_PANEL_LUMINANCE_CONTROL_CAPABLE) &&
            (intel_dp->edp_dpcd[3] & DP_EDP_SMOOTH_BRIGHTNESS_CAPABLE)) {
                drm_dbg_kms(display->drm,
                            "[CONNECTOR:%d:%s] AUX Luminance Based Backlight Control Supported!\n",
                            connector->base.base.id, connector->base.name);
                panel->backlight.edp.vesa.luminance_control_support = true;
                return true;
        }

        if (drm_edp_backlight_supported(intel_dp->edp_dpcd)) {
                drm_dbg_kms(display->drm,
                            "[CONNECTOR:%d:%s] AUX Backlight Control Supported!\n",
                            connector->base.base.id, connector->base.name);
                return true;
        }
        return false;
}

static const struct intel_panel_bl_funcs intel_dp_hdr_bl_funcs = {
        .setup = intel_dp_aux_hdr_setup_backlight,
        .enable = intel_dp_aux_hdr_enable_backlight,
        .disable = intel_dp_aux_hdr_disable_backlight,
        .set = intel_dp_aux_hdr_set_backlight,
        .get = intel_dp_aux_hdr_get_backlight,
};

static const struct intel_panel_bl_funcs intel_dp_vesa_bl_funcs = {
        .setup = intel_dp_aux_vesa_setup_backlight,
        .enable = intel_dp_aux_vesa_enable_backlight,
        .disable = intel_dp_aux_vesa_disable_backlight,
        .set = intel_dp_aux_vesa_set_backlight,
        .get = intel_dp_aux_vesa_get_backlight,
};

int intel_dp_aux_init_backlight_funcs(struct intel_connector *connector)
{
        struct intel_display *display = to_intel_display(connector);
        struct intel_dp *intel_dp = intel_attached_dp(connector);
        struct drm_device *dev = connector->base.dev;
        struct intel_panel *panel = &connector->panel;
        bool try_intel_interface = false, try_vesa_interface = false;

        /* Check the VBT and user's module parameters to figure out which
         * interfaces to probe
         */
        switch (display->params.enable_dpcd_backlight) {
        case INTEL_DP_AUX_BACKLIGHT_OFF:
                return -ENODEV;
        case INTEL_DP_AUX_BACKLIGHT_AUTO:
                switch (panel->vbt.backlight.type) {
                case INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE:
                        try_vesa_interface = true;
                        break;
                case INTEL_BACKLIGHT_DISPLAY_DDI:
                        try_intel_interface = true;
                        break;
                default:
                        return -ENODEV;
                }
                break;
        case INTEL_DP_AUX_BACKLIGHT_ON:
                if (panel->vbt.backlight.type != INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE)
                        try_intel_interface = true;

                try_vesa_interface = true;
                break;
        case INTEL_DP_AUX_BACKLIGHT_FORCE_VESA:
                try_vesa_interface = true;
                break;
        case INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL:
                try_intel_interface = true;
                break;
        }

        /* For eDP 1.5 and above we are supposed to use VESA interface for brightness control */
        if (intel_dp->edp_dpcd[0] >= DP_EDP_15)
                try_vesa_interface = true;

        /*
         * Since Intel has their own backlight control interface, the majority of machines out there
         * using DPCD backlight controls with Intel GPUs will be using this interface as opposed to
         * the VESA interface. However, other GPUs (such as Nvidia's) will always use the VESA
         * interface. This means that there's quite a number of panels out there that will advertise
         * support for both interfaces, primarily systems with Intel/Nvidia hybrid GPU setups.
         *
         * There's a catch to this though: on many panels that advertise support for both
         * interfaces, the VESA backlight interface will stop working once we've programmed the
         * panel with Intel's OUI - which is also required for us to be able to detect Intel's
         * backlight interface at all. This means that the only sensible way for us to detect both
         * interfaces is to probe for Intel's first, and VESA's second.
         */
        if (try_intel_interface && intel_dp_aux_supports_hdr_backlight(connector) &&
            intel_dp->edp_dpcd[0] <= DP_EDP_14b) {
                drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Using Intel proprietary eDP backlight controls\n",
                            connector->base.base.id, connector->base.name);
                panel->backlight.funcs = &intel_dp_hdr_bl_funcs;
                return 0;
        }

        if (try_vesa_interface && intel_dp_aux_supports_vesa_backlight(connector)) {
                drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Using VESA eDP backlight controls\n",
                            connector->base.base.id, connector->base.name);
                panel->backlight.funcs = &intel_dp_vesa_bl_funcs;
                return 0;
        }

        return -ENODEV;
}