/*
 * Copyright (c) 2016 Intel Corporation
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 */

#ifndef __DRM_BRIDGE_H__
#define __DRM_BRIDGE_H__

#include <linux/list.h>
#include <linux/ctype.h>
#include <drm/drm_mode_object.h>
#include <drm/drm_modes.h>

struct drm_bridge;
struct drm_panel;

/**
 * struct drm_bridge_funcs - drm_bridge control functions
 */
struct drm_bridge_funcs {
        /**
         * @attach:
         *
         * This callback is invoked whenever our bridge is being attached to a
         * &drm_encoder.
         *
         * The attach callback is optional.
         *
         * RETURNS:
         *
         * Zero on success, error code on failure.
         */
        int (*attach)(struct drm_bridge *bridge);

        /**
         * @detach:
         *
         * This callback is invoked whenever our bridge is being detached from a
         * &drm_encoder.
         *
         * The detach callback is optional.
         */
        void (*detach)(struct drm_bridge *bridge);

        /**
         * @mode_valid:
         *
         * This callback is used to check if a specific mode is valid in this
         * bridge. This should be implemented if the bridge has some sort of
         * restriction in the modes it can display. For example, a given bridge
         * may be responsible to set a clock value. If the clock can not
         * produce all the values for the available modes then this callback
         * can be used to restrict the number of modes to only the ones that
         * can be displayed.
         *
         * This hook is used by the probe helpers to filter the mode list in
         * drm_helper_probe_single_connector_modes(), and it is used by the
         * atomic helpers to validate modes supplied by userspace in
         * drm_atomic_helper_check_modeset().
         *
         * This function is optional.
         *
         * NOTE:
         *
         * Since this function is both called from the check phase of an atomic
         * commit, and the mode validation in the probe paths it is not allowed
         * to look at anything else but the passed-in mode, and validate it
         * against configuration-invariant hardward constraints. Any further
         * limits which depend upon the configuration can only be checked in
         * @mode_fixup.
         *
         * RETURNS:
         *
         * drm_mode_status Enum
         */
        enum drm_mode_status (*mode_valid)(struct drm_bridge *crtc,
                                           const struct drm_display_mode *mode);

        /**
         * @mode_fixup:
         *
         * This callback is used to validate and adjust a mode. The paramater
         * mode is the display mode that should be fed to the next element in
         * the display chain, either the final &drm_connector or the next
         * &drm_bridge. The parameter adjusted_mode is the input mode the bridge
         * requires. It can be modified by this callback and does not need to
         * match mode. See also &drm_crtc_state.adjusted_mode for more details.
         *
         * This is the only hook that allows a bridge to reject a modeset. If
         * this function passes all other callbacks must succeed for this
         * configuration.
         *
         * The mode_fixup callback is optional.
         *
         * NOTE:
         *
         * This function is called in the check phase of atomic modesets, which
         * can be aborted for any reason (including on userspace's request to
         * just check whether a configuration would be possible). Drivers MUST
         * NOT touch any persistent state (hardware or software) or data
         * structures except the passed in @state parameter.
         *
         * Also beware that userspace can request its own custom modes, neither
         * core nor helpers filter modes to the list of probe modes reported by
         * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
         * that modes are filtered consistently put any bridge constraints and
         * limits checks into @mode_valid.
         *
         * RETURNS:
         *
         * True if an acceptable configuration is possible, false if the modeset
         * operation should be rejected.
         */
        bool (*mode_fixup)(struct drm_bridge *bridge,
                           const struct drm_display_mode *mode,
                           struct drm_display_mode *adjusted_mode);
        /**
         * @disable:
         *
         * This callback should disable the bridge. It is called right before
         * the preceding element in the display pipe is disabled. If the
         * preceding element is a bridge this means it's called before that
         * bridge's @disable vfunc. If the preceding element is a &drm_encoder
         * it's called right before the &drm_encoder_helper_funcs.disable,
         * &drm_encoder_helper_funcs.prepare or &drm_encoder_helper_funcs.dpms
         * hook.
         *
         * The bridge can assume that the display pipe (i.e. clocks and timing
         * signals) feeding it is still running when this callback is called.
         *
         * The disable callback is optional.
         */
        void (*disable)(struct drm_bridge *bridge);

        /**
         * @post_disable:
         *
         * This callback should disable the bridge. It is called right after the
         * preceding element in the display pipe is disabled. If the preceding
         * element is a bridge this means it's called after that bridge's
         * @post_disable function. If the preceding element is a &drm_encoder
         * it's called right after the encoder's
         * &drm_encoder_helper_funcs.disable, &drm_encoder_helper_funcs.prepare
         * or &drm_encoder_helper_funcs.dpms hook.
         *
         * The bridge must assume that the display pipe (i.e. clocks and timing
         * singals) feeding it is no longer running when this callback is
         * called.
         *
         * The post_disable callback is optional.
         */
        void (*post_disable)(struct drm_bridge *bridge);

        /**
         * @mode_set:
         *
         * This callback should set the given mode on the bridge. It is called
         * after the @mode_set callback for the preceding element in the display
         * pipeline has been called already. If the bridge is the first element
         * then this would be &drm_encoder_helper_funcs.mode_set. The display
         * pipe (i.e.  clocks and timing signals) is off when this function is
         * called.
         */
        void (*mode_set)(struct drm_bridge *bridge,
                         struct drm_display_mode *mode,
                         struct drm_display_mode *adjusted_mode);
        /**
         * @pre_enable:
         *
         * This callback should enable the bridge. It is called right before
         * the preceding element in the display pipe is enabled. If the
         * preceding element is a bridge this means it's called before that
         * bridge's @pre_enable function. If the preceding element is a
         * &drm_encoder it's called right before the encoder's
         * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
         * &drm_encoder_helper_funcs.dpms hook.
         *
         * The display pipe (i.e. clocks and timing signals) feeding this bridge
         * will not yet be running when this callback is called. The bridge must
         * not enable the display link feeding the next bridge in the chain (if
         * there is one) when this callback is called.
         *
         * The pre_enable callback is optional.
         */
        void (*pre_enable)(struct drm_bridge *bridge);

        /**
         * @enable:
         *
         * This callback should enable the bridge. It is called right after
         * the preceding element in the display pipe is enabled. If the
         * preceding element is a bridge this means it's called after that
         * bridge's @enable function. If the preceding element is a
         * &drm_encoder it's called right after the encoder's
         * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
         * &drm_encoder_helper_funcs.dpms hook.
         *
         * The bridge can assume that the display pipe (i.e. clocks and timing
         * signals) feeding it is running when this callback is called. This
         * callback must enable the display link feeding the next bridge in the
         * chain if there is one.
         *
         * The enable callback is optional.
         */
        void (*enable)(struct drm_bridge *bridge);
};

/**
 * struct drm_bridge - central DRM bridge control structure
 * @dev: DRM device this bridge belongs to
 * @encoder: encoder to which this bridge is connected
 * @next: the next bridge in the encoder chain
 * @of_node: device node pointer to the bridge
 * @list: to keep track of all added bridges
 * @funcs: control functions
 * @driver_private: pointer to the bridge driver's internal context
 */
struct drm_bridge {
        struct drm_device *dev;
        struct drm_encoder *encoder;
        struct drm_bridge *next;
#ifdef CONFIG_OF
        struct device_node *of_node;
#endif
        struct list_head list;

        const struct drm_bridge_funcs *funcs;
        void *driver_private;
};

int drm_bridge_add(struct drm_bridge *bridge);
void drm_bridge_remove(struct drm_bridge *bridge);
struct drm_bridge *of_drm_find_bridge(struct device_node *np);
int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
                      struct drm_bridge *previous);

bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
                        const struct drm_display_mode *mode,
                        struct drm_display_mode *adjusted_mode);
enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
                                           const struct drm_display_mode *mode);
void drm_bridge_disable(struct drm_bridge *bridge);
void drm_bridge_post_disable(struct drm_bridge *bridge);
void drm_bridge_mode_set(struct drm_bridge *bridge,
                        struct drm_display_mode *mode,
                        struct drm_display_mode *adjusted_mode);
void drm_bridge_pre_enable(struct drm_bridge *bridge);
void drm_bridge_enable(struct drm_bridge *bridge);

#ifdef CONFIG_DRM_PANEL_BRIDGE
struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel,
                                        u32 connector_type);
void drm_panel_bridge_remove(struct drm_bridge *bridge);
#endif

#endif