// 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 void drm_bridge_connector_debugfs_init(struct drm_connector *connector,
struct dentry *root)
{
struct drm_bridge_connector *bridge_connector =
to_drm_bridge_connector(connector);
struct drm_encoder *encoder = bridge_connector->encoder;
struct drm_bridge *bridge;
list_for_each_entry(bridge, &encoder->bridge_chain, chain_node) {
if (bridge->funcs->debugfs_init)
bridge->funcs->debugfs_init(bridge, root);
}
}
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,
.debugfs_init = drm_bridge_connector_debugfs_init,
};
/* -----------------------------------------------------------------------------
* 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 (!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);
