#include <linux/component.h>
#include <linux/export.h>
#include <linux/list.h>
#include <linux/of_graph.h>
#include <drm/drmP.h>
#include <drm/drm_crtc.h>
#include <drm/drm_encoder.h>
#include <drm/drm_of.h>

static void drm_release_of(struct device *dev, void *data)
{
        of_node_put(data);
}

/**
 * drm_crtc_port_mask - find the mask of a registered CRTC by port OF node
 * @dev: DRM device
 * @port: port OF node
 *
 * Given a port OF node, return the possible mask of the corresponding
 * CRTC within a device's list of CRTCs.  Returns zero if not found.
 */
static uint32_t drm_crtc_port_mask(struct drm_device *dev,
                                   struct device_node *port)
{
        unsigned int index = 0;
        struct drm_crtc *tmp;

        drm_for_each_crtc(tmp, dev) {
                if (tmp->port == port)
                        return 1 << index;

                index++;
        }

        return 0;
}

/**
 * drm_of_find_possible_crtcs - find the possible CRTCs for an encoder port
 * @dev: DRM device
 * @port: encoder port to scan for endpoints
 *
 * Scan all endpoints attached to a port, locate their attached CRTCs,
 * and generate the DRM mask of CRTCs which may be attached to this
 * encoder.
 *
 * See Documentation/devicetree/bindings/graph.txt for the bindings.
 */
uint32_t drm_of_find_possible_crtcs(struct drm_device *dev,
                                    struct device_node *port)
{
        struct device_node *remote_port, *ep;
        uint32_t possible_crtcs = 0;

        for_each_endpoint_of_node(port, ep) {
                remote_port = of_graph_get_remote_port(ep);
                if (!remote_port) {
                        of_node_put(ep);
                        return 0;
                }

                possible_crtcs |= drm_crtc_port_mask(dev, remote_port);

                of_node_put(remote_port);
        }

        return possible_crtcs;
}
EXPORT_SYMBOL(drm_of_find_possible_crtcs);

/**
 * drm_of_component_match_add - Add a component helper OF node match rule
 * @master: master device
 * @matchptr: component match pointer
 * @compare: compare function used for matching component
 * @node: of_node
 */
void drm_of_component_match_add(struct device *master,
                                struct component_match **matchptr,
                                int (*compare)(struct device *, void *),
                                struct device_node *node)
{
        of_node_get(node);
        component_match_add_release(master, matchptr, drm_release_of,
                                    compare, node);
}
EXPORT_SYMBOL_GPL(drm_of_component_match_add);

/**
 * drm_of_component_probe - Generic probe function for a component based master
 * @dev: master device containing the OF node
 * @compare_of: compare function used for matching components
 * @master_ops: component master ops to be used
 *
 * Parse the platform device OF node and bind all the components associated
 * with the master. Interface ports are added before the encoders in order to
 * satisfy their .bind requirements
 * See Documentation/devicetree/bindings/graph.txt for the bindings.
 *
 * Returns zero if successful, or one of the standard error codes if it fails.
 */
int drm_of_component_probe(struct device *dev,
                           int (*compare_of)(struct device *, void *),
                           const struct component_master_ops *m_ops)
{
        struct device_node *ep, *port, *remote;
        struct component_match *match = NULL;
        int i;

        if (!dev->of_node)
                return -EINVAL;

        /*
         * Bind the crtc's ports first, so that drm_of_find_possible_crtcs()
         * called from encoder's .bind callbacks works as expected
         */
        for (i = 0; ; i++) {
                port = of_parse_phandle(dev->of_node, "ports", i);
                if (!port)
                        break;

                if (!of_device_is_available(port->parent)) {
                        of_node_put(port);
                        continue;
                }

                drm_of_component_match_add(dev, &match, compare_of, port);
                of_node_put(port);
        }

        if (i == 0) {
                dev_err(dev, "missing 'ports' property\n");
                return -ENODEV;
        }

        if (!match) {
                dev_err(dev, "no available port\n");
                return -ENODEV;
        }

        /*
         * For bound crtcs, bind the encoders attached to their remote endpoint
         */
        for (i = 0; ; i++) {
                port = of_parse_phandle(dev->of_node, "ports", i);
                if (!port)
                        break;

                if (!of_device_is_available(port->parent)) {
                        of_node_put(port);
                        continue;
                }

                for_each_child_of_node(port, ep) {
                        remote = of_graph_get_remote_port_parent(ep);
                        if (!remote || !of_device_is_available(remote)) {
                                of_node_put(remote);
                                continue;
                        } else if (!of_device_is_available(remote->parent)) {
                                dev_warn(dev, "parent device of %s is not available\n",
                                         remote->full_name);
                                of_node_put(remote);
                                continue;
                        }

                        drm_of_component_match_add(dev, &match, compare_of,
                                                   remote);
                        of_node_put(remote);
                }
                of_node_put(port);
        }

        return component_master_add_with_match(dev, m_ops, match);
}
EXPORT_SYMBOL(drm_of_component_probe);

/*
 * drm_of_encoder_active_endpoint - return the active encoder endpoint
 * @node: device tree node containing encoder input ports
 * @encoder: drm_encoder
 *
 * Given an encoder device node and a drm_encoder with a connected crtc,
 * parse the encoder endpoint connecting to the crtc port.
 */
int drm_of_encoder_active_endpoint(struct device_node *node,
                                   struct drm_encoder *encoder,
                                   struct of_endpoint *endpoint)
{
        struct device_node *ep;
        struct drm_crtc *crtc = encoder->crtc;
        struct device_node *port;
        int ret;

        if (!node || !crtc)
                return -EINVAL;

        for_each_endpoint_of_node(node, ep) {
                port = of_graph_get_remote_port(ep);
                of_node_put(port);
                if (port == crtc->port) {
                        ret = of_graph_parse_endpoint(ep, endpoint);
                        of_node_put(ep);
                        return ret;
                }
        }

        return -EINVAL;
}
EXPORT_SYMBOL_GPL(drm_of_encoder_active_endpoint);