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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * Copyright (C) 2019 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
- */
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/slab.h>
- #include <drm/drm_atomic_state_helper.h>
- #include <drm/drm_bridge.h>
- #include <drm/drm_bridge_connector.h>
- #include <drm/drm_connector.h>
- #include <drm/drm_device.h>
- #include <drm/drm_edid.h>
- #include <drm/drm_modeset_helper_vtables.h>
- #include <drm/drm_probe_helper.h>
- /**
- * DOC: overview
- *
- * The DRM bridge connector helper object provides a DRM connector
- * implementation that wraps a chain of &struct drm_bridge. The connector
- * operations are fully implemented based on the operations of the bridges in
- * the chain, and don't require any intervention from the display controller
- * driver at runtime.
- *
- * To use the helper, display controller drivers create a bridge connector with
- * a call to drm_bridge_connector_init(). This associates the newly created
- * connector with the chain of bridges passed to the function and registers it
- * with the DRM device. At that point the connector becomes fully usable, no
- * further operation is needed.
- *
- * The DRM bridge connector operations are implemented based on the operations
- * provided by the bridges in the chain. Each connector operation is delegated
- * to the bridge closest to the connector (at the end of the chain) that
- * provides the relevant functionality.
- *
- * To make use of this helper, all bridges in the chain shall report bridge
- * operation flags (&drm_bridge->ops) and bridge output type
- * (&drm_bridge->type), as well as the DRM_BRIDGE_ATTACH_NO_CONNECTOR attach
- * flag (none of the bridges shall create a DRM connector directly).
- */
- /**
- * struct drm_bridge_connector - A connector backed by a chain of bridges
- */
- struct drm_bridge_connector {
- /**
- * @base: The base DRM connector
- */
- struct drm_connector base;
- /**
- * @encoder:
- *
- * The encoder at the start of the bridges chain.
- */
- struct drm_encoder *encoder;
- /**
- * @bridge_edid:
- *
- * The last bridge in the chain (closest to the connector) that provides
- * EDID read support, if any (see &DRM_BRIDGE_OP_EDID).
- */
- struct drm_bridge *bridge_edid;
- /**
- * @bridge_hpd:
- *
- * The last bridge in the chain (closest to the connector) that provides
- * hot-plug detection notification, if any (see &DRM_BRIDGE_OP_HPD).
- */
- struct drm_bridge *bridge_hpd;
- /**
- * @bridge_detect:
- *
- * The last bridge in the chain (closest to the connector) that provides
- * connector detection, if any (see &DRM_BRIDGE_OP_DETECT).
- */
- struct drm_bridge *bridge_detect;
- /**
- * @bridge_modes:
- *
- * The last bridge in the chain (closest to the connector) that provides
- * connector modes detection, if any (see &DRM_BRIDGE_OP_MODES).
- */
- struct drm_bridge *bridge_modes;
- };
- #define to_drm_bridge_connector(x) \
- container_of(x, struct drm_bridge_connector, base)
- /* -----------------------------------------------------------------------------
- * Bridge Connector Hot-Plug Handling
- */
- static void drm_bridge_connector_hpd_notify(struct drm_connector *connector,
- enum drm_connector_status status)
- {
- struct drm_bridge_connector *bridge_connector =
- to_drm_bridge_connector(connector);
- struct drm_bridge *bridge;
- /* Notify all bridges in the pipeline of hotplug events. */
- drm_for_each_bridge_in_chain(bridge_connector->encoder, bridge) {
- if (bridge->funcs->hpd_notify)
- bridge->funcs->hpd_notify(bridge, status);
- }
- }
- static void drm_bridge_connector_hpd_cb(void *cb_data,
- enum drm_connector_status status)
- {
- struct drm_bridge_connector *drm_bridge_connector = cb_data;
- struct drm_connector *connector = &drm_bridge_connector->base;
- struct drm_device *dev = connector->dev;
- enum drm_connector_status old_status;
- mutex_lock(&dev->mode_config.mutex);
- old_status = connector->status;
- connector->status = status;
- mutex_unlock(&dev->mode_config.mutex);
- if (old_status == status)
- return;
- drm_bridge_connector_hpd_notify(connector, status);
- drm_kms_helper_hotplug_event(dev);
- }
- /**
- * drm_bridge_connector_enable_hpd - Enable hot-plug detection for the connector
- * @connector: The DRM bridge connector
- *
- * This function enables hot-plug detection for the given bridge connector.
- * This is typically used by display drivers in their resume handler.
- */
- void drm_bridge_connector_enable_hpd(struct drm_connector *connector)
- {
- struct drm_bridge_connector *bridge_connector =
- to_drm_bridge_connector(connector);
- struct drm_bridge *hpd = bridge_connector->bridge_hpd;
- if (hpd)
- drm_bridge_hpd_enable(hpd, drm_bridge_connector_hpd_cb,
- bridge_connector);
- }
- EXPORT_SYMBOL_GPL(drm_bridge_connector_enable_hpd);
- /**
- * drm_bridge_connector_disable_hpd - Disable hot-plug detection for the
- * connector
- * @connector: The DRM bridge connector
- *
- * This function disables hot-plug detection for the given bridge connector.
- * This is typically used by display drivers in their suspend handler.
- */
- void drm_bridge_connector_disable_hpd(struct drm_connector *connector)
- {
- struct drm_bridge_connector *bridge_connector =
- to_drm_bridge_connector(connector);
- struct drm_bridge *hpd = bridge_connector->bridge_hpd;
- if (hpd)
- drm_bridge_hpd_disable(hpd);
- }
- EXPORT_SYMBOL_GPL(drm_bridge_connector_disable_hpd);
- /* -----------------------------------------------------------------------------
- * Bridge Connector Functions
- */
- static enum drm_connector_status
- drm_bridge_connector_detect(struct drm_connector *connector, bool force)
- {
- struct drm_bridge_connector *bridge_connector =
- to_drm_bridge_connector(connector);
- struct drm_bridge *detect = bridge_connector->bridge_detect;
- enum drm_connector_status status;
- if (detect) {
- status = detect->funcs->detect(detect);
- drm_bridge_connector_hpd_notify(connector, status);
- } else {
- switch (connector->connector_type) {
- case DRM_MODE_CONNECTOR_DPI:
- case DRM_MODE_CONNECTOR_LVDS:
- case DRM_MODE_CONNECTOR_DSI:
- case DRM_MODE_CONNECTOR_eDP:
- status = connector_status_connected;
- break;
- default:
- status = connector_status_unknown;
- break;
- }
- }
- return status;
- }
- static void drm_bridge_connector_destroy(struct drm_connector *connector)
- {
- struct drm_bridge_connector *bridge_connector =
- to_drm_bridge_connector(connector);
- if (bridge_connector->bridge_hpd) {
- struct drm_bridge *hpd = bridge_connector->bridge_hpd;
- drm_bridge_hpd_disable(hpd);
- }
- drm_connector_unregister(connector);
- drm_connector_cleanup(connector);
- kfree(bridge_connector);
- }
- static const struct drm_connector_funcs drm_bridge_connector_funcs = {
- .reset = drm_atomic_helper_connector_reset,
- .detect = drm_bridge_connector_detect,
- .fill_modes = drm_helper_probe_single_connector_modes,
- .destroy = drm_bridge_connector_destroy,
- .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
- .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
- };
- /* -----------------------------------------------------------------------------
- * Bridge Connector Helper Functions
- */
- static int drm_bridge_connector_get_modes_edid(struct drm_connector *connector,
- struct drm_bridge *bridge)
- {
- enum drm_connector_status status;
- struct edid *edid;
- int n;
- status = drm_bridge_connector_detect(connector, false);
- if (status != connector_status_connected)
- goto no_edid;
- edid = bridge->funcs->get_edid(bridge, connector);
- if (!edid || !drm_edid_is_valid(edid)) {
- kfree(edid);
- goto no_edid;
- }
- drm_connector_update_edid_property(connector, edid);
- n = drm_add_edid_modes(connector, edid);
- kfree(edid);
- return n;
- no_edid:
- drm_connector_update_edid_property(connector, NULL);
- return 0;
- }
- static int drm_bridge_connector_get_modes(struct drm_connector *connector)
- {
- struct drm_bridge_connector *bridge_connector =
- to_drm_bridge_connector(connector);
- struct drm_bridge *bridge;
- /*
- * If display exposes EDID, then we parse that in the normal way to
- * build table of supported modes.
- */
- bridge = bridge_connector->bridge_edid;
- if (bridge)
- return drm_bridge_connector_get_modes_edid(connector, bridge);
- /*
- * Otherwise if the display pipeline reports modes (e.g. with a fixed
- * resolution panel or an analog TV output), query it.
- */
- bridge = bridge_connector->bridge_modes;
- if (bridge)
- return bridge->funcs->get_modes(bridge, connector);
- /*
- * We can't retrieve modes, which can happen for instance for a DVI or
- * VGA output with the DDC bus unconnected. The KMS core will add the
- * default modes.
- */
- return 0;
- }
- static const struct drm_connector_helper_funcs drm_bridge_connector_helper_funcs = {
- .get_modes = drm_bridge_connector_get_modes,
- /* No need for .mode_valid(), the bridges are checked by the core. */
- };
- /* -----------------------------------------------------------------------------
- * Bridge Connector Initialisation
- */
- /**
- * drm_bridge_connector_init - Initialise a connector for a chain of bridges
- * @drm: the DRM device
- * @encoder: the encoder where the bridge chain starts
- *
- * Allocate, initialise and register a &drm_bridge_connector with the @drm
- * device. The connector is associated with a chain of bridges that starts at
- * the @encoder. All bridges in the chain shall report bridge operation flags
- * (&drm_bridge->ops) and bridge output type (&drm_bridge->type), and none of
- * them may create a DRM connector directly.
- *
- * Returns a pointer to the new connector on success, or a negative error
- * pointer otherwise.
- */
- struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
- struct drm_encoder *encoder)
- {
- struct drm_bridge_connector *bridge_connector;
- struct drm_connector *connector;
- struct i2c_adapter *ddc = NULL;
- struct drm_bridge *bridge;
- int connector_type;
- bridge_connector = kzalloc(sizeof(*bridge_connector), GFP_KERNEL);
- if (!bridge_connector)
- return ERR_PTR(-ENOMEM);
- bridge_connector->encoder = encoder;
- /*
- * TODO: Handle doublescan_allowed, stereo_allowed and
- * ycbcr_420_allowed.
- */
- connector = &bridge_connector->base;
- connector->interlace_allowed = true;
- /*
- * Initialise connector status handling. First locate the furthest
- * bridges in the pipeline that support HPD and output detection. Then
- * initialise the connector polling mode, using HPD if available and
- * falling back to polling if supported. If neither HPD nor output
- * detection are available, we don't support hotplug detection at all.
- */
- connector_type = DRM_MODE_CONNECTOR_Unknown;
- drm_for_each_bridge_in_chain(encoder, bridge) {
- if (!bridge->interlace_allowed)
- connector->interlace_allowed = false;
- if (bridge->ops & DRM_BRIDGE_OP_EDID)
- bridge_connector->bridge_edid = bridge;
- if (bridge->ops & DRM_BRIDGE_OP_HPD)
- bridge_connector->bridge_hpd = bridge;
- if (bridge->ops & DRM_BRIDGE_OP_DETECT)
- bridge_connector->bridge_detect = bridge;
- if (bridge->ops & DRM_BRIDGE_OP_MODES)
- bridge_connector->bridge_modes = bridge;
- if (!drm_bridge_get_next_bridge(bridge))
- connector_type = bridge->type;
- if (bridge->ddc)
- ddc = bridge->ddc;
- }
- if (connector_type == DRM_MODE_CONNECTOR_Unknown) {
- kfree(bridge_connector);
- return ERR_PTR(-EINVAL);
- }
- drm_connector_init_with_ddc(drm, connector, &drm_bridge_connector_funcs,
- connector_type, ddc);
- drm_connector_helper_add(connector, &drm_bridge_connector_helper_funcs);
- if (bridge_connector->bridge_hpd)
- connector->polled = DRM_CONNECTOR_POLL_HPD;
- else if (bridge_connector->bridge_detect)
- connector->polled = DRM_CONNECTOR_POLL_CONNECT
- | DRM_CONNECTOR_POLL_DISCONNECT;
- return connector;
- }
- EXPORT_SYMBOL_GPL(drm_bridge_connector_init);
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