/* * Copyright (c) 2014 Samsung Electronics Co., Ltd * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sub license, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the * next paragraph) shall be included in all copies or substantial portions * of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. */ #include <linux/err.h> #include <linux/media-bus-format.h> #include <linux/module.h> #include <linux/mutex.h> #include <drm/drm_atomic_state_helper.h> #include <drm/drm_bridge.h> #include <drm/drm_debugfs.h> #include <drm/drm_edid.h> #include <drm/drm_encoder.h> #include <drm/drm_file.h> #include <drm/drm_of.h> #include <drm/drm_print.h> #include "drm_crtc_internal.h" /** * DOC: overview * * &struct drm_bridge represents a device that hangs on to an encoder. These are * handy when a regular &drm_encoder entity isn't enough to represent the entire * encoder chain. * * A bridge is always attached to a single &drm_encoder at a time, but can be * either connected to it directly, or through a chain of bridges:: * * [ CRTC ---> ] Encoder ---> Bridge A ---> Bridge B * * Here, the output of the encoder feeds to bridge A, and that furthers feeds to * bridge B. Bridge chains can be arbitrarily long, and shall be fully linear: * Chaining multiple bridges to the output of a bridge, or the same bridge to * the output of different bridges, is not supported. * * &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 * encoder chain. */ /** * DOC: display driver integration * * Display drivers are responsible for linking encoders with the first bridge * in the chains. This is done by acquiring the appropriate bridge with * devm_drm_of_get_bridge(). Once acquired, the bridge shall be attached to the * encoder with a call to drm_bridge_attach(). * * Bridges are responsible for linking themselves with the next bridge in the * chain, if any. This is done the same way as for encoders, with the call to * drm_bridge_attach() occurring in the &drm_bridge_funcs.attach operation. * * Once these links are created, the bridges can participate along with encoder * functions to perform mode validation and fixup (through * drm_bridge_chain_mode_valid() and drm_atomic_bridge_chain_check()), mode * setting (through drm_bridge_chain_mode_set()), enable (through * drm_atomic_bridge_chain_pre_enable() and drm_atomic_bridge_chain_enable()) * and disable (through drm_atomic_bridge_chain_disable() and * drm_atomic_bridge_chain_post_disable()). Those functions call the * corresponding operations provided in &drm_bridge_funcs in sequence for all * bridges in the chain. * * For display drivers that use the atomic helpers * drm_atomic_helper_check_modeset(), * drm_atomic_helper_commit_modeset_enables() and * drm_atomic_helper_commit_modeset_disables() (either directly in hand-rolled * commit check and commit tail handlers, or through the higher-level * drm_atomic_helper_check() and drm_atomic_helper_commit_tail() or * drm_atomic_helper_commit_tail_rpm() helpers), this is done transparently and * 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). */ /** * DOC: special care dsi * * The interaction between the bridges and other frameworks involved in * the probing of the upstream driver and the bridge driver can be * challenging. Indeed, there's multiple cases that needs to be * considered: * * - The upstream driver doesn't use the component framework and isn't a * MIPI-DSI host. In this case, the bridge driver will probe at some * point and the upstream driver should try to probe again by returning * EPROBE_DEFER as long as the bridge driver hasn't probed. * * - The upstream driver doesn't use the component framework, but is a * MIPI-DSI host. The bridge device uses the MIPI-DCS commands to be * controlled. In this case, the bridge device is a child of the * display device and when it will probe it's assured that the display * device (and MIPI-DSI host) is present. The upstream driver will be * assured that the bridge driver is connected between the * &mipi_dsi_host_ops.attach and &mipi_dsi_host_ops.detach operations. * Therefore, it must run mipi_dsi_host_register() in its probe * function, and then run drm_bridge_attach() in its * &mipi_dsi_host_ops.attach hook. * * - The upstream driver uses the component framework and is a MIPI-DSI * host. The bridge device uses the MIPI-DCS commands to be * controlled. This is the same situation than above, and can run * mipi_dsi_host_register() in either its probe or bind hooks. * * - The upstream driver uses the component framework and is a MIPI-DSI * host. The bridge device uses a separate bus (such as I2C) to be * controlled. In this case, there's no correlation between the probe * of the bridge and upstream drivers, so care must be taken to avoid * an endless EPROBE_DEFER loop, with each driver waiting for the * other to probe. * * The ideal pattern to cover the last item (and all the others in the * MIPI-DSI host driver case) is to split the operations like this: * * - The MIPI-DSI host driver must run mipi_dsi_host_register() in its * probe hook. It will make sure that the MIPI-DSI host sticks around, * and that the driver's bind can be called. * * - In its probe hook, the bridge driver must try to find its MIPI-DSI * host, register as a MIPI-DSI device and attach the MIPI-DSI device * to its host. The bridge driver is now functional. * * - In its &struct mipi_dsi_host_ops.attach hook, the MIPI-DSI host can * now add its component. Its bind hook will now be called and since * the bridge driver is attached and registered, we can now look for * and attach it. * * At this point, we're now certain that both the upstream driver and * the bridge driver are functional and we can't have a deadlock-like * situation when probing. */ /** * DOC: dsi bridge operations * * DSI host interfaces are expected to be implemented as bridges rather than * encoders, however there are a few aspects of their operation that need to * be defined in order to provide a consistent interface. * * A DSI host should keep the PHY powered down until the pre_enable operation is * called. All lanes are in an undefined idle state up to this point, and it * must not be assumed that it is LP-11. * pre_enable should initialise the PHY, set the data lanes to LP-11, and the * clock lane to either LP-11 or HS depending on the mode_flag * %MIPI_DSI_CLOCK_NON_CONTINUOUS. * * Ordinarily the downstream bridge DSI peripheral pre_enable will have been * called before the DSI host. If the DSI peripheral requires LP-11 and/or * the clock lane to be in HS mode prior to pre_enable, then it can set the * &pre_enable_prev_first flag to request the pre_enable (and * post_disable) order to be altered to enable the DSI host first. * * Either the CRTC being enabled, or the DSI host enable operation should switch * the host to actively transmitting video on the data lanes. * * The reverse also applies. The DSI host disable operation or stopping the CRTC * should stop transmitting video, and the data lanes should return to the LP-11 * state. The DSI host &post_disable operation should disable the PHY. * If the &pre_enable_prev_first flag is set, then the DSI peripheral's * bridge &post_disable will be called before the DSI host's post_disable. * * Whilst it is valid to call &host_transfer prior to pre_enable or after * post_disable, the exact state of the lanes is undefined at this point. The * DSI host should initialise the interface, transmit the data, and then disable * the interface again. * * Ultra Low Power State (ULPS) is not explicitly supported by DRM. If * implemented, it therefore needs to be handled entirely within the DSI Host * driver. */ static DEFINE_MUTEX(bridge_lock); static LIST_HEAD(bridge_list); /** * drm_bridge_add - add the given bridge to the global bridge list * * @bridge: bridge control structure */ void drm_bridge_add(struct drm_bridge *bridge) { … } EXPORT_SYMBOL(…); static void drm_bridge_remove_void(void *bridge) { … } /** * devm_drm_bridge_add - devm managed version of drm_bridge_add() * * @dev: device to tie the bridge lifetime to * @bridge: bridge control structure * * This is the managed version of drm_bridge_add() which automatically * calls drm_bridge_remove() when @dev is unbound. * * Return: 0 if no error or negative error code. */ int devm_drm_bridge_add(struct device *dev, struct drm_bridge *bridge) { … } EXPORT_SYMBOL(…); /** * drm_bridge_remove - remove the given bridge from the global bridge list * * @bridge: bridge control structure */ void drm_bridge_remove(struct drm_bridge *bridge) { … } EXPORT_SYMBOL(…); static struct drm_private_state * drm_bridge_atomic_duplicate_priv_state(struct drm_private_obj *obj) { … } static void drm_bridge_atomic_destroy_priv_state(struct drm_private_obj *obj, struct drm_private_state *s) { … } static const struct drm_private_state_funcs drm_bridge_priv_state_funcs = …; /** * drm_bridge_attach - attach the bridge to an encoder's chain * * @encoder: DRM encoder * @bridge: bridge to attach * @previous: previous bridge in the chain (optional) * @flags: DRM_BRIDGE_ATTACH_* flags * * Called by a kms driver to link the bridge to an encoder's chain. The previous * argument specifies the previous bridge in the chain. If NULL, the bridge is * linked directly at the encoder's output. Otherwise it is linked at the * previous bridge's output. * * If non-NULL the previous bridge must be already attached by a call to this * function. * * Note that bridges attached to encoders are auto-detached during encoder * cleanup in drm_encoder_cleanup(), so drm_bridge_attach() should generally * *not* be balanced with a drm_bridge_detach() in driver code. * * RETURNS: * Zero on success, error code on failure */ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge, struct drm_bridge *previous, enum drm_bridge_attach_flags flags) { … } EXPORT_SYMBOL(…); void drm_bridge_detach(struct drm_bridge *bridge) { … } /** * DOC: bridge operations * * Bridge drivers expose operations through the &drm_bridge_funcs structure. * The DRM internals (atomic and CRTC helpers) use the helpers defined in * drm_bridge.c to call bridge operations. Those operations are divided in * three big categories to support different parts of the bridge usage. * * - The encoder-related operations support control of the bridges in the * chain, and are roughly counterparts to the &drm_encoder_helper_funcs * operations. They are used by the legacy CRTC and the atomic modeset * helpers to perform mode validation, fixup and setting, and enable and * disable the bridge automatically. * * The enable and disable operations are split in * &drm_bridge_funcs.pre_enable, &drm_bridge_funcs.enable, * &drm_bridge_funcs.disable and &drm_bridge_funcs.post_disable to provide * finer-grained control. * * Bridge drivers may implement the legacy version of those operations, or * the atomic version (prefixed with atomic\_), in which case they shall also * implement the atomic state bookkeeping operations * (&drm_bridge_funcs.atomic_duplicate_state, * &drm_bridge_funcs.atomic_destroy_state and &drm_bridge_funcs.reset). * Mixing atomic and non-atomic versions of the operations is not supported. * * - The bus format negotiation operations * &drm_bridge_funcs.atomic_get_output_bus_fmts and * &drm_bridge_funcs.atomic_get_input_bus_fmts allow bridge drivers to * negotiate the formats transmitted between bridges in the chain when * multiple formats are supported. Negotiation for formats is performed * transparently for display drivers by the atomic modeset helpers. Only * atomic versions of those operations exist, bridge drivers that need to * implement them shall thus also implement the atomic version of the * encoder-related operations. This feature is not supported by the legacy * CRTC helpers. * * - The connector-related operations support implementing a &drm_connector * based on a chain of bridges. DRM bridges traditionally create a * &drm_connector for bridges meant to be used at the end of the chain. This * puts additional burden on bridge drivers, especially for bridges that may * be used in the middle of a chain or at the end of it. Furthermore, it * requires all operations of the &drm_connector to be handled by a single * bridge, which doesn't always match the hardware architecture. * * To simplify bridge drivers and make the connector implementation more * flexible, a new model allows bridges to unconditionally skip creation of * &drm_connector and instead expose &drm_bridge_funcs operations to support * an externally-implemented &drm_connector. Those operations are * &drm_bridge_funcs.detect, &drm_bridge_funcs.get_modes, * &drm_bridge_funcs.get_edid, &drm_bridge_funcs.hpd_notify, * &drm_bridge_funcs.hpd_enable and &drm_bridge_funcs.hpd_disable. When * implemented, display drivers shall create a &drm_connector instance for * each chain of bridges, and implement those connector instances based on * the bridge connector operations. * * Bridge drivers shall implement the connector-related operations for all * the features that the bridge hardware support. For instance, if a bridge * supports reading EDID, the &drm_bridge_funcs.get_edid shall be * implemented. This however doesn't mean that the DDC lines are wired to the * bridge on a particular platform, as they could also be connected to an I2C * controller of the SoC. Support for the connector-related operations on the * running platform is reported through the &drm_bridge.ops flags. Bridge * drivers shall detect which operations they can support on the platform * (usually this information is provided by ACPI or DT), and set the * &drm_bridge.ops flags for all supported operations. A flag shall only be * set if the corresponding &drm_bridge_funcs operation is implemented, but * an implemented operation doesn't necessarily imply that the corresponding * flag will be set. Display drivers shall use the &drm_bridge.ops flags to * decide which bridge to delegate a connector operation to. This mechanism * allows providing a single static const &drm_bridge_funcs instance in * bridge drivers, improving security by storing function pointers in * read-only memory. * * In order to ease transition, bridge drivers may support both the old and * new models by making connector creation optional and implementing the * connected-related bridge operations. Connector creation is then controlled * by the flags argument to the drm_bridge_attach() function. Display drivers * that support the new model and create connectors themselves shall set the * %DRM_BRIDGE_ATTACH_NO_CONNECTOR flag, and bridge drivers shall then skip * connector creation. For intermediate bridges in the chain, the flag shall * be passed to the drm_bridge_attach() call for the downstream bridge. * Bridge drivers that implement the new model only shall return an error * from their &drm_bridge_funcs.attach handler when the * %DRM_BRIDGE_ATTACH_NO_CONNECTOR flag is not set. New display drivers * should use the new model, and convert the bridge drivers they use if * needed, in order to gradually transition to the new model. */ /** * drm_bridge_chain_mode_valid - validate the mode against all bridges in the * encoder chain. * @bridge: bridge control structure * @info: display info against which the mode shall be validated * @mode: desired mode to be validated * * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder * chain, starting from the first bridge to the last. If at least one bridge * does not accept the mode the function returns the error code. * * Note: the bridge passed should be the one closest to the encoder. * * RETURNS: * MODE_OK on success, drm_mode_status Enum error code on failure */ enum drm_mode_status drm_bridge_chain_mode_valid(struct drm_bridge *bridge, const struct drm_display_info *info, const struct drm_display_mode *mode) { … } EXPORT_SYMBOL(…); /** * drm_bridge_chain_mode_set - set proposed mode for all bridges in the * encoder chain * @bridge: bridge control structure * @mode: desired mode to be set for the encoder chain * @adjusted_mode: updated mode that works for this encoder chain * * Calls &drm_bridge_funcs.mode_set op for all the bridges in the * encoder chain, starting from the first bridge to the last. * * Note: the bridge passed should be the one closest to the encoder */ void drm_bridge_chain_mode_set(struct drm_bridge *bridge, const struct drm_display_mode *mode, const struct drm_display_mode *adjusted_mode) { … } EXPORT_SYMBOL(…); /** * drm_atomic_bridge_chain_disable - disables all bridges in the encoder chain * @bridge: bridge control structure * @old_state: old atomic state * * Calls &drm_bridge_funcs.atomic_disable (falls back on * &drm_bridge_funcs.disable) op for all the bridges in the encoder chain, * starting from the last bridge to the first. These are called before calling * &drm_encoder_helper_funcs.atomic_disable * * Note: the bridge passed should be the one closest to the encoder */ void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge, struct drm_atomic_state *old_state) { … } EXPORT_SYMBOL(…); static void drm_atomic_bridge_call_post_disable(struct drm_bridge *bridge, struct drm_atomic_state *old_state) { … } /** * drm_atomic_bridge_chain_post_disable - cleans up after disabling all bridges * in the encoder chain * @bridge: bridge control structure * @old_state: old atomic state * * Calls &drm_bridge_funcs.atomic_post_disable (falls back on * &drm_bridge_funcs.post_disable) op for all the bridges in the encoder chain, * starting from the first bridge to the last. These are called after completing * &drm_encoder_helper_funcs.atomic_disable * * If a bridge sets @pre_enable_prev_first, then the @post_disable for that * bridge will be called before the previous one to reverse the @pre_enable * calling direction. * * Example: * Bridge A ---> Bridge B ---> Bridge C ---> Bridge D ---> Bridge E * * With pre_enable_prev_first flag enable in Bridge B, D, E then the resulting * @post_disable order would be, * Bridge B, Bridge A, Bridge E, Bridge D, Bridge C. * * Note: the bridge passed should be the one closest to the encoder */ void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge, struct drm_atomic_state *old_state) { … } EXPORT_SYMBOL(…); static void drm_atomic_bridge_call_pre_enable(struct drm_bridge *bridge, struct drm_atomic_state *old_state) { … } /** * drm_atomic_bridge_chain_pre_enable - prepares for enabling all bridges in * the encoder chain * @bridge: bridge control structure * @old_state: old atomic state * * Calls &drm_bridge_funcs.atomic_pre_enable (falls back on * &drm_bridge_funcs.pre_enable) op for all the bridges in the encoder chain, * starting from the last bridge to the first. These are called before calling * &drm_encoder_helper_funcs.atomic_enable * * If a bridge sets @pre_enable_prev_first, then the pre_enable for the * prev bridge will be called before pre_enable of this bridge. * * Example: * Bridge A ---> Bridge B ---> Bridge C ---> Bridge D ---> Bridge E * * With pre_enable_prev_first flag enable in Bridge B, D, E then the resulting * @pre_enable order would be, * Bridge C, Bridge D, Bridge E, Bridge A, Bridge B. * * Note: the bridge passed should be the one closest to the encoder */ void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge, struct drm_atomic_state *old_state) { … } EXPORT_SYMBOL(…); /** * drm_atomic_bridge_chain_enable - enables all bridges in the encoder chain * @bridge: bridge control structure * @old_state: old atomic state * * Calls &drm_bridge_funcs.atomic_enable (falls back on * &drm_bridge_funcs.enable) op for all the bridges in the encoder chain, * starting from the first bridge to the last. These are called after completing * &drm_encoder_helper_funcs.atomic_enable * * Note: the bridge passed should be the one closest to the encoder */ void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge, struct drm_atomic_state *old_state) { … } EXPORT_SYMBOL(…); static int drm_atomic_bridge_check(struct drm_bridge *bridge, struct drm_crtc_state *crtc_state, struct drm_connector_state *conn_state) { … } static int select_bus_fmt_recursive(struct drm_bridge *first_bridge, struct drm_bridge *cur_bridge, struct drm_crtc_state *crtc_state, struct drm_connector_state *conn_state, u32 out_bus_fmt) { … } /* * This function is called by &drm_atomic_bridge_chain_check() just before * calling &drm_bridge_funcs.atomic_check() on all elements of the chain. * It performs bus format negotiation between bridge elements. The negotiation * happens in reverse order, starting from the last element in the chain up to * @bridge. * * Negotiation starts by retrieving supported output bus formats on the last * bridge element and testing them one by one. The test is recursive, meaning * that for each tested output format, the whole chain will be walked backward, * and each element will have to choose an input bus format that can be * transcoded to the requested output format. When a bridge element does not * support transcoding into a specific output format -ENOTSUPP is returned and * the next bridge element will have to try a different format. If none of the * combinations worked, -ENOTSUPP is returned and the atomic modeset will fail. * * This implementation is relying on * &drm_bridge_funcs.atomic_get_output_bus_fmts() and * &drm_bridge_funcs.atomic_get_input_bus_fmts() to gather supported * input/output formats. * * When &drm_bridge_funcs.atomic_get_output_bus_fmts() is not implemented by * the last element of the chain, &drm_atomic_bridge_chain_select_bus_fmts() * tries a single format: &drm_connector.display_info.bus_formats[0] if * available, MEDIA_BUS_FMT_FIXED otherwise. * * When &drm_bridge_funcs.atomic_get_input_bus_fmts() is not implemented, * &drm_atomic_bridge_chain_select_bus_fmts() skips the negotiation on the * bridge element that lacks this hook and asks the previous element in the * chain to try MEDIA_BUS_FMT_FIXED. It's up to bridge drivers to decide what * to do in that case (fail if they want to enforce bus format negotiation, or * provide a reasonable default if they need to support pipelines where not * all elements support bus format negotiation). */ static int drm_atomic_bridge_chain_select_bus_fmts(struct drm_bridge *bridge, struct drm_crtc_state *crtc_state, struct drm_connector_state *conn_state) { … } static void drm_atomic_bridge_propagate_bus_flags(struct drm_bridge *bridge, struct drm_connector *conn, struct drm_atomic_state *state) { … } /** * drm_atomic_bridge_chain_check() - Do an atomic check on the bridge chain * @bridge: bridge control structure * @crtc_state: new CRTC state * @conn_state: new connector state * * First trigger a bus format negotiation before calling * &drm_bridge_funcs.atomic_check() (falls back on * &drm_bridge_funcs.mode_fixup()) op for all the bridges in the encoder chain, * starting from the last bridge to the first. These are called before calling * &drm_encoder_helper_funcs.atomic_check() * * RETURNS: * 0 on success, a negative error code on failure */ int drm_atomic_bridge_chain_check(struct drm_bridge *bridge, struct drm_crtc_state *crtc_state, struct drm_connector_state *conn_state) { … } EXPORT_SYMBOL(…); /** * drm_bridge_detect - check if anything is attached to the bridge output * @bridge: bridge control structure * * If the bridge supports output detection, as reported by the * DRM_BRIDGE_OP_DETECT bridge ops flag, call &drm_bridge_funcs.detect for the * bridge and return the connection status. Otherwise return * connector_status_unknown. * * RETURNS: * The detection status on success, or connector_status_unknown if the bridge * doesn't support output detection. */ enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge) { … } EXPORT_SYMBOL_GPL(…); /** * drm_bridge_get_modes - fill all modes currently valid for the sink into the * @connector * @bridge: bridge control structure * @connector: the connector to fill with modes * * If the bridge supports output modes retrieval, as reported by the * DRM_BRIDGE_OP_MODES bridge ops flag, call &drm_bridge_funcs.get_modes to * fill the connector with all valid modes and return the number of modes * added. Otherwise return 0. * * RETURNS: * The number of modes added to the connector. */ int drm_bridge_get_modes(struct drm_bridge *bridge, struct drm_connector *connector) { … } EXPORT_SYMBOL_GPL(…); /** * drm_bridge_edid_read - read the EDID data of the connected display * @bridge: bridge control structure * @connector: the connector to read EDID for * * If the bridge supports output EDID retrieval, as reported by the * DRM_BRIDGE_OP_EDID bridge ops flag, call &drm_bridge_funcs.edid_read to get * the EDID and return it. Otherwise return NULL. * * RETURNS: * The retrieved EDID on success, or NULL otherwise. */ const struct drm_edid *drm_bridge_edid_read(struct drm_bridge *bridge, struct drm_connector *connector) { … } EXPORT_SYMBOL_GPL(…); /** * drm_bridge_hpd_enable - enable hot plug detection for the bridge * @bridge: bridge control structure * @cb: hot-plug detection callback * @data: data to be passed to the hot-plug detection callback * * Call &drm_bridge_funcs.hpd_enable if implemented and register the given @cb * and @data as hot plug notification callback. From now on the @cb will be * called with @data when an output status change is detected by the bridge, * until hot plug notification gets disabled with drm_bridge_hpd_disable(). * * Hot plug detection is supported only if the DRM_BRIDGE_OP_HPD flag is set in * bridge->ops. This function shall not be called when the flag is not set. * * Only one hot plug detection callback can be registered at a time, it is an * error to call this function when hot plug detection is already enabled for * the bridge. */ void drm_bridge_hpd_enable(struct drm_bridge *bridge, void (*cb)(void *data, enum drm_connector_status status), void *data) { … } EXPORT_SYMBOL_GPL(…); /** * drm_bridge_hpd_disable - disable hot plug detection for the bridge * @bridge: bridge control structure * * Call &drm_bridge_funcs.hpd_disable if implemented and unregister the hot * plug detection callback previously registered with drm_bridge_hpd_enable(). * Once this function returns the callback will not be called by the bridge * when an output status change occurs. * * Hot plug detection is supported only if the DRM_BRIDGE_OP_HPD flag is set in * bridge->ops. This function shall not be called when the flag is not set. */ void drm_bridge_hpd_disable(struct drm_bridge *bridge) { … } EXPORT_SYMBOL_GPL(…); /** * drm_bridge_hpd_notify - notify hot plug detection events * @bridge: bridge control structure * @status: output connection status * * Bridge drivers shall call this function to report hot plug events when they * detect a change in the output status, when hot plug detection has been * enabled by drm_bridge_hpd_enable(). * * This function shall be called in a context that can sleep. */ void drm_bridge_hpd_notify(struct drm_bridge *bridge, enum drm_connector_status status) { … } EXPORT_SYMBOL_GPL(…); #ifdef CONFIG_OF /** * of_drm_find_bridge - find the bridge corresponding to the device node in * the global bridge list * * @np: device node * * RETURNS: * drm_bridge control struct on success, NULL on failure */ struct drm_bridge *of_drm_find_bridge(struct device_node *np) { … } EXPORT_SYMBOL(…); #endif MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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