diff options
Diffstat (limited to 'drivers/gpu/drm/drm_bridge_connector.c')
| -rw-r--r-- | drivers/gpu/drm/drm_bridge_connector.c | 403 |
1 files changed, 403 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_bridge_connector.c b/drivers/gpu/drm/drm_bridge_connector.c new file mode 100644 index 000000000..1c7d93652 --- /dev/null +++ b/drivers/gpu/drm/drm_bridge_connector.c @@ -0,0 +1,403 @@ +// 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, *panel_bridge = NULL; + 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 (drm_bridge_is_panel(bridge)) + panel_bridge = bridge; + } + + 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; + drm_bridge_connector_enable_hpd(connector); + } + else if (bridge_connector->bridge_detect) + connector->polled = DRM_CONNECTOR_POLL_CONNECT + | DRM_CONNECTOR_POLL_DISCONNECT; + + if (panel_bridge) + drm_panel_bridge_set_orientation(connector, panel_bridge); + + return connector; +} +EXPORT_SYMBOL_GPL(drm_bridge_connector_init); |