@@ -145,6 +145,12 @@ Bridge Operations
.. kernel-doc:: drivers/gpu/drm/drm_bridge.c
:doc: bridge operations
+Bridge Connector Helper
+-----------------------
+
+.. kernel-doc:: drivers/gpu/drm/drm_bridge_connector.c
+ :doc: overview
+
Bridge Helper Reference
-------------------------
@@ -155,6 +161,12 @@ Bridge Helper Reference
.. kernel-doc:: drivers/gpu/drm/drm_bridge.c
:export:
+Bridge Connector Helper Reference
+---------------------------------
+
+.. kernel-doc:: drivers/gpu/drm/drm_bridge_connector.c
+ :export:
+
Panel-Bridge Helper Reference
-----------------------------
@@ -39,7 +39,8 @@ obj-$(CONFIG_DRM_VRAM_HELPER) += drm_vram_helper.o
drm_ttm_helper-y := drm_gem_ttm_helper.o
obj-$(CONFIG_DRM_TTM_HELPER) += drm_ttm_helper.o
-drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_dsc.o drm_probe_helper.o \
+drm_kms_helper-y := drm_bridge_connector.o drm_crtc_helper.o drm_dp_helper.o \
+ drm_dsc.o drm_probe_helper.o \
drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \
drm_kms_helper_common.o drm_dp_dual_mode_helper.o \
drm_simple_kms_helper.o drm_modeset_helper.o \
@@ -79,6 +79,12 @@
* requires no intervention from the driver. For other drivers, the relevant
* DRM bridge chain functions shall be called manually.
*
+ * Bridges also participate in implementing the &drm_connector at the end of
+ * the bridge chain. Display drivers may use the drm_bridge_connector_init()
+ * helper to create the &drm_connector, or implement it manually on top of the
+ * connector-related operations exposed by the bridge (see the overview
+ * documentation of bridge operations for more details).
+ *
* &drm_bridge, like &drm_panel, aren't &drm_mode_object entities like planes,
* CRTCs, encoders or connectors and hence are not visible to userspace. They
* just provide additional hooks to get the desired output at the end of the
new file mode 100644
@@ -0,0 +1,379 @@
+// 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:
+ 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);
new file mode 100644
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2019 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ */
+
+#ifndef __DRM_BRIDGE_CONNECTOR_H__
+#define __DRM_BRIDGE_CONNECTOR_H__
+
+struct drm_connector;
+struct drm_device;
+struct drm_encoder;
+
+void drm_bridge_connector_enable_hpd(struct drm_connector *connector);
+void drm_bridge_connector_disable_hpd(struct drm_connector *connector);
+struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
+ struct drm_encoder *encoder);
+
+#endif /* __DRM_BRIDGE_CONNECTOR_H__ */