drm/doc: polish for sturct drm_connector

- switch everything over to inline comments
- add notes about locking, links to functions and other related stuff
- also include a note about Ville's soon-to-be-merged
  drm_connector_for_each_possible_encoder().

Also check that all the hyperlinks in drm_connector.h work and fix
them as needed.
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180709084016.23750-5-daniel.vetter@ffwll.ch

include/drm/drm_connector.h

@@ -561,8 +561,7 @@ struct drm_connector_funcs {
 	 * received for this output connector->edid must be NULL.
 	 *
 	 * Drivers using the probe helpers should use
-	 * drm_helper_probe_single_connector_modes() or
-	 * drm_helper_probe_single_connector_modes_nomerge() to implement this
+	 * drm_helper_probe_single_connector_modes() to implement this
 	 * function.
 	 *
 	 * RETURNS:
@@ -773,45 +772,6 @@ struct drm_cmdline_mode {
 
 /**
  * struct drm_connector - central DRM connector control structure
- * @dev: parent DRM device
- * @kdev: kernel device for sysfs attributes
- * @attr: sysfs attributes
- * @head: list management
- * @base: base KMS object
- * @name: human readable name, can be overwritten by the driver
- * @connector_type: one of the DRM_MODE_CONNECTOR_<foo> types from drm_mode.h
- * @connector_type_id: index into connector type enum
- * @interlace_allowed: can this connector handle interlaced modes?
- * @doublescan_allowed: can this connector handle doublescan?
- * @stereo_allowed: can this connector handle stereo modes?
- * @funcs: connector control functions
- * @edid_blob_ptr: DRM property containing EDID if present
- * @properties: property tracking for this connector
- * @dpms: current dpms state
- * @helper_private: mid-layer private data
- * @cmdline_mode: mode line parsed from the kernel cmdline for this connector
- * @force: a DRM_FORCE_<foo> state for forced mode sets
- * @override_edid: has the EDID been overwritten through debugfs for testing?
- * @encoder_ids: valid encoders for this connector
- * @eld: EDID-like data, if present
- * @latency_present: AV delay info from ELD, if found
- * @video_latency: video latency info from ELD, if found
- * @audio_latency: audio latency info from ELD, if found
- * @null_edid_counter: track sinks that give us all zeros for the EDID
- * @bad_edid_counter: track sinks that give us an EDID with invalid checksum
- * @edid_corrupt: indicates whether the last read EDID was corrupt
- * @debugfs_entry: debugfs directory for this connector
- * @has_tile: is this connector connected to a tiled monitor
- * @tile_group: tile group for the connected monitor
- * @tile_is_single_monitor: whether the tile is one monitor housing
- * @num_h_tile: number of horizontal tiles in the tile group
- * @num_v_tile: number of vertical tiles in the tile group
- * @tile_h_loc: horizontal location of this tile
- * @tile_v_loc: vertical location of this tile
- * @tile_h_size: horizontal size of this tile.
- * @tile_v_size: vertical size of this tile.
- * @scaling_mode_property:  Optional atomic property to control the upscaling.
- * @content_protection_property: Optional property to control content protection
  *
  * Each connector may be connected to one or more CRTCs, or may be clonable by
  * another connector if they can share a CRTC.  Each connector also has a specific
@@ -819,13 +779,27 @@ struct drm_cmdline_mode {
  * span multiple monitors).
  */
 struct drm_connector {
+	/** @dev: parent DRM device */
 	struct drm_device *dev;
+	/** @kdev: kernel device for sysfs attributes */
 	struct device *kdev;
+	/** @attr: sysfs attributes */
 	struct device_attribute *attr;
+
+	/**
+	 * @head:
+	 *
+	 * List of all connectors on a @dev, linked from
+	 * &drm_mode_config.connector_list. Protected by
+	 * &drm_mode_config.connector_list_lock, but please only use
+	 * &drm_connector_list_iter to walk this list.
+	 */
 	struct list_head head;
 
+	/** @base: base KMS object */
 	struct drm_mode_object base;
 
+	/** @name: human readable name, can be overwritten by the driver */
 	char *name;
 
 	/**
@@ -843,10 +817,30 @@ struct drm_connector {
 	 */
 	unsigned index;
 
+	/**
+	 * @connector_type:
+	 * one of the DRM_MODE_CONNECTOR_<foo> types from drm_mode.h
+	 */
 	int connector_type;
+	/** @connector_type_id: index into connector type enum */
 	int connector_type_id;
+	/**
+	 * @interlace_allowed:
+	 * Can this connector handle interlaced modes? Only used by
+	 * drm_helper_probe_single_connector_modes() for mode filtering.
+	 */
 	bool interlace_allowed;
+	/**
+	 * @doublescan_allowed:
+	 * Can this connector handle doublescan? Only used by
+	 * drm_helper_probe_single_connector_modes() for mode filtering.
+	 */
 	bool doublescan_allowed;
+	/**
+	 * @stereo_allowed:
+	 * Can this connector handle stereo modes? Only used by
+	 * drm_helper_probe_single_connector_modes() for mode filtering.
+	 */
 	bool stereo_allowed;
 
 	/**
@@ -895,45 +889,42 @@ struct drm_connector {
 	 * Protected by &drm_mode_config.mutex.
 	 */
 	struct drm_display_info display_info;
+
+	/** @funcs: connector control functions */
 	const struct drm_connector_funcs *funcs;
 
+	/**
+	 * @edid_blob_ptr: DRM property containing EDID if present. Protected by
+	 * &drm_mode_config.mutex. This should be updated only by calling
+	 * drm_mode_connector_update_edid_property().
+	 */
 	struct drm_property_blob *edid_blob_ptr;
+
+	/** @properties: property tracking for this connector */
 	struct drm_object_properties properties;
 
+	/**
+	 * @scaling_mode_property: Optional atomic property to control the
+	 * upscaling. See drm_connector_attach_content_protection_property().
+	 */
 	struct drm_property *scaling_mode_property;
 
 	/**
 	 * @content_protection_property: DRM ENUM property for content
-	 * protection
+	 * protection. See drm_connector_attach_content_protection_property().
 	 */
 	struct drm_property *content_protection_property;
 
 	/**
 	 * @path_blob_ptr:
 	 *
-	 * DRM blob property data for the DP MST path property.
+	 * DRM blob property data for the DP MST path property. This should only
+	 * be updated by calling drm_mode_connector_set_path_property().
 	 */
 	struct drm_property_blob *path_blob_ptr;
 
-	/**
-	 * @tile_blob_ptr:
-	 *
-	 * DRM blob property data for the tile property (used mostly by DP MST).
-	 * This is meant for screens which are driven through separate display
-	 * pipelines represented by &drm_crtc, which might not be running with
-	 * genlocked clocks. For tiled panels which are genlocked, like
-	 * dual-link LVDS or dual-link DSI, the driver should try to not expose
-	 * the tiling and virtualize both &drm_crtc and &drm_plane if needed.
-	 */
-	struct drm_property_blob *tile_blob_ptr;
-
-/* should we poll this connector for connects and disconnects */
-/* hot plug detectable */
 #define DRM_CONNECTOR_POLL_HPD (1 << 0)
-/* poll for connections */
 #define DRM_CONNECTOR_POLL_CONNECT (1 << 1)
-/* can cleanly poll for disconnections without flickering the screen */
-/* DACs should rarely do this without a lot of testing */
 #define DRM_CONNECTOR_POLL_DISCONNECT (1 << 2)
 
 	/**
@@ -950,25 +941,40 @@ struct drm_connector {
 	 *     Periodically poll the connector for connection.
 	 *
 	 * DRM_CONNECTOR_POLL_DISCONNECT
-	 *     Periodically poll the connector for disconnection.
+	 *     Periodically poll the connector for disconnection, without
+	 *     causing flickering even when the connector is in use. DACs should
+	 *     rarely do this without a lot of testing.
 	 *
 	 * Set to 0 for connectors that don't support connection status
 	 * discovery.
 	 */
 	uint8_t polled;
 
-	/* requested DPMS state */
+	/**
+	 * @dpms: Current dpms state. For legacy drivers the
+	 * &drm_connector_funcs.dpms callback must update this. For atomic
+	 * drivers, this is handled by the core atomic code, and drivers must
+	 * only take &drm_crtc_state.active into account.
+	 */
 	int dpms;
 
+	/** @helper_private: mid-layer private data */
 	const struct drm_connector_helper_funcs *helper_private;
 
-	/* forced on connector */
+	/** @cmdline_mode: mode line parsed from the kernel cmdline for this connector */
 	struct drm_cmdline_mode cmdline_mode;
+	/** @force: a DRM_FORCE_<foo> state for forced mode sets */
 	enum drm_connector_force force;
+	/** @override_edid: has the EDID been overwritten through debugfs for testing? */
 	bool override_edid;
 
 #define DRM_CONNECTOR_MAX_ENCODER 3
+	/**
+	 * @encoder_ids: Valid encoders for this connector. Please only use
+	 * drm_connector_for_each_possible_encoder() to enumerate these.
+	 */
 	uint32_t encoder_ids[DRM_CONNECTOR_MAX_ENCODER];
+
 	/**
 	 * @encoder: Currently bound encoder driving this connector, if any.
 	 * Only really meaningful for non-atomic drivers. Atomic drivers should
@@ -978,19 +984,37 @@ struct drm_connector {
 	struct drm_encoder *encoder;
 
 #define MAX_ELD_BYTES	128
-	/* EDID bits */
+	/** @eld: EDID-like data, if present */
 	uint8_t eld[MAX_ELD_BYTES];
+	/** @latency_present: AV delay info from ELD, if found */
 	bool latency_present[2];
-	int video_latency[2];	/* [0]: progressive, [1]: interlaced */
+	/**
+	 * @video_latency: Video latency info from ELD, if found.
+	 * [0]: progressive, [1]: interlaced
+	 */
+	int video_latency[2];
+	/**
+	 * @audio_latency: audio latency info from ELD, if found
+	 * [0]: progressive, [1]: interlaced
+	 */
 	int audio_latency[2];
-	int null_edid_counter; /* needed to workaround some HW bugs where we get all 0s */
+	/**
+	 * @null_edid_counter: track sinks that give us all zeros for the EDID.
+	 * Needed to workaround some HW bugs where we get all 0s
+	 */
+	int null_edid_counter;
+
+	/** @bad_edid_counter: track sinks that give us an EDID with invalid checksum */
 	unsigned bad_edid_counter;
 
-	/* Flag for raw EDID header corruption - used in Displayport
-	 * compliance testing - * Displayport Link CTS Core 1.2 rev1.1 4.2.2.6
+	/**
+	 * @edid_corrupt: Indicates whether the last read EDID was corrupt. Used
+	 * in Displayport compliance testing - Displayport Link CTS Core 1.2
+	 * rev1.1 4.2.2.6
 	 */
 	bool edid_corrupt;
 
+	/** @debugfs_entry: debugfs directory for this connector */
 	struct dentry *debugfs_entry;
 
 	/**
@@ -998,7 +1022,7 @@ struct drm_connector {
 	 *
 	 * Current atomic state for this connector.
 	 *
-	 * This is protected by @drm_mode_config.connection_mutex. Note that
+	 * This is protected by &drm_mode_config.connection_mutex. Note that
 	 * nonblocking atomic commits access the current connector state without
 	 * taking locks. Either by going through the &struct drm_atomic_state
 	 * pointers, see for_each_oldnew_connector_in_state(),
@@ -1009,19 +1033,44 @@ struct drm_connector {
 	 */
 	struct drm_connector_state *state;
 
-	/* DisplayID bits */
+	/* DisplayID bits. FIXME: Extract into a substruct? */
+
+	/**
+	 * @tile_blob_ptr:
+	 *
+	 * DRM blob property data for the tile property (used mostly by DP MST).
+	 * This is meant for screens which are driven through separate display
+	 * pipelines represented by &drm_crtc, which might not be running with
+	 * genlocked clocks. For tiled panels which are genlocked, like
+	 * dual-link LVDS or dual-link DSI, the driver should try to not expose
+	 * the tiling and virtualize both &drm_crtc and &drm_plane if needed.
+	 *
+	 * This should only be updated by calling
+	 * drm_mode_connector_set_tile_property().
+	 */
+	struct drm_property_blob *tile_blob_ptr;
+
+	/** @has_tile: is this connector connected to a tiled monitor */
 	bool has_tile;
+	/** @tile_group: tile group for the connected monitor */
 	struct drm_tile_group *tile_group;
+	/** @tile_is_single_monitor: whether the tile is one monitor housing */
 	bool tile_is_single_monitor;
 
+	/** @num_h_tile: number of horizontal tiles in the tile group */
+	/** @num_v_tile: number of vertical tiles in the tile group */
 	uint8_t num_h_tile, num_v_tile;
+	/** @tile_h_loc: horizontal location of this tile */
+	/** @tile_v_loc: vertical location of this tile */
 	uint8_t tile_h_loc, tile_v_loc;
+	/** @tile_h_size: horizontal size of this tile. */
+	/** @tile_v_size: vertical size of this tile. */
 	uint16_t tile_h_size, tile_v_size;
 
 	/**
 	 * @free_node:
 	 *
-	 * List used only by &drm_connector_iter to be able to clean up a
+	 * List used only by &drm_connector_list_iter to be able to clean up a
 	 * connector from any context, in conjunction with
 	 * &drm_mode_config.connector_free_work.
 	 */