/* $NetBSD: drm_bridge.c,v 1.3.8.1 2020/01/05 09:42:05 martin Exp $ */ /* * 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 __KERNEL_RCSID(0, "$NetBSD: drm_bridge.c,v 1.3.8.1 2020/01/05 09:42:05 martin Exp $"); #include #include #include #include "drm/drmP.h" /** * DOC: overview * * 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 associated to a single drm_encoder at a time, but can be * either connected to it directly, or through an intermediate bridge: * * encoder ---> bridge B ---> bridge A * * Here, the output of the encoder feeds to bridge B, and that furthers feeds to * bridge A. * * The driver using the bridge is responsible to make the associations between * the encoder and bridges. Once these links are made, the bridges will * participate along with encoder functions to perform mode_set/enable/disable * through the ops provided in drm_bridge_funcs. * * drm_bridge, like drm_panel, aren't drm_mode_object entities like planes, * crtcs, encoders or connectors. They just provide additional hooks to get the * desired output at the end of the encoder chain. */ #ifdef __NetBSD__ static struct mutex bridge_lock; static struct list_head bridge_list = LIST_HEAD_INIT(bridge_list); #else static DEFINE_MUTEX(bridge_lock); static LIST_HEAD(bridge_list); #endif #ifdef __NetBSD__ void drm_bridge_init_lock(void) { linux_mutex_init(&bridge_lock); } void drm_bridge_fini_lock(void) { linux_mutex_destroy(&bridge_lock); } #endif /** * drm_bridge_add - add the given bridge to the global bridge list * * @bridge: bridge control structure * * RETURNS: * Unconditionally returns Zero. */ int drm_bridge_add(struct drm_bridge *bridge) { mutex_lock(&bridge_lock); list_add_tail(&bridge->list, &bridge_list); mutex_unlock(&bridge_lock); return 0; } EXPORT_SYMBOL(drm_bridge_add); /** * drm_bridge_remove - remove the given bridge from the global bridge list * * @bridge: bridge control structure */ void drm_bridge_remove(struct drm_bridge *bridge) { mutex_lock(&bridge_lock); list_del_init(&bridge->list); mutex_unlock(&bridge_lock); } EXPORT_SYMBOL(drm_bridge_remove); /** * drm_bridge_attach - associate given bridge to our DRM device * * @dev: DRM device * @bridge: bridge control structure * * called by a kms driver to link one of our encoder/bridge to the given * bridge. * * Note that setting up links between the bridge and our encoder/bridge * objects needs to be handled by the kms driver itself * * RETURNS: * Zero on success, error code on failure */ int drm_bridge_attach(struct drm_device *dev, struct drm_bridge *bridge) { if (!dev || !bridge) return -EINVAL; if (bridge->dev) return -EBUSY; bridge->dev = dev; if (bridge->funcs->attach) return bridge->funcs->attach(bridge); return 0; } EXPORT_SYMBOL(drm_bridge_attach); /** * DOC: bridge callbacks * * The drm_bridge_funcs ops are populated by the bridge driver. The drm * internals(atomic and crtc helpers) use the helpers defined in drm_bridge.c * These helpers call a specific drm_bridge_funcs op for all the bridges * during encoder configuration. * * When creating a bridge driver, one can implement drm_bridge_funcs op with * the help of these rough rules: * * pre_enable: this contains things needed to be done for the bridge before * its clock and timings are enabled by its source. For a bridge, its source * is generally the encoder or bridge just before it in the encoder chain. * * enable: this contains things needed to be done for the bridge once its * source is enabled. In other words, enable is called once the source is * ready with clock and timing needed by the bridge. * * disable: this contains things needed to be done for the bridge assuming * that its source is still enabled, i.e. clock and timings are still on. * * post_disable: this contains things needed to be done for the bridge once * its source is disabled, i.e. once clocks and timings are off. * * mode_fixup: this should fixup the given mode for the bridge. It is called * after the encoder's mode fixup. mode_fixup can also reject a mode completely * if it's unsuitable for the hardware. * * mode_set: this sets up the mode for the bridge. It assumes that its source * (an encoder or a bridge) has set the mode too. */ /** * drm_bridge_mode_fixup - fixup proposed mode for all bridges in the * encoder chain * @bridge: bridge control structure * @mode: desired mode to be set for the bridge * @adjusted_mode: updated mode that works for this bridge * * Calls 'mode_fixup' drm_bridge_funcs 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 * * RETURNS: * true on success, false on failure */ bool drm_bridge_mode_fixup(struct drm_bridge *bridge, const struct drm_display_mode *mode, struct drm_display_mode *adjusted_mode) { bool ret = true; if (!bridge) return true; if (bridge->funcs->mode_fixup) ret = bridge->funcs->mode_fixup(bridge, mode, adjusted_mode); ret = ret && drm_bridge_mode_fixup(bridge->next, mode, adjusted_mode); return ret; } EXPORT_SYMBOL(drm_bridge_mode_fixup); /** * drm_bridge_disable - calls 'disable' drm_bridge_funcs op for all * bridges in the encoder chain. * @bridge: bridge control structure * * Calls 'disable' drm_bridge_funcs op for all the bridges in the encoder * chain, starting from the last bridge to the first. These are called before * calling the encoder's prepare op. * * Note: the bridge passed should be the one closest to the encoder */ void drm_bridge_disable(struct drm_bridge *bridge) { if (!bridge) return; drm_bridge_disable(bridge->next); bridge->funcs->disable(bridge); } EXPORT_SYMBOL(drm_bridge_disable); /** * drm_bridge_post_disable - calls 'post_disable' drm_bridge_funcs op for * all bridges in the encoder chain. * @bridge: bridge control structure * * Calls 'post_disable' drm_bridge_funcs op for all the bridges in the * encoder chain, starting from the first bridge to the last. These are called * after completing the encoder's prepare op. * * Note: the bridge passed should be the one closest to the encoder */ void drm_bridge_post_disable(struct drm_bridge *bridge) { if (!bridge) return; bridge->funcs->post_disable(bridge); drm_bridge_post_disable(bridge->next); } EXPORT_SYMBOL(drm_bridge_post_disable); /** * drm_bridge_mode_set - set proposed mode for all bridges in the * encoder chain * @bridge: bridge control structure * @mode: desired mode to be set for the bridge * @adjusted_mode: updated mode that works for this bridge * * Calls 'mode_set' drm_bridge_funcs 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_mode_set(struct drm_bridge *bridge, struct drm_display_mode *mode, struct drm_display_mode *adjusted_mode) { if (!bridge) return; if (bridge->funcs->mode_set) bridge->funcs->mode_set(bridge, mode, adjusted_mode); drm_bridge_mode_set(bridge->next, mode, adjusted_mode); } EXPORT_SYMBOL(drm_bridge_mode_set); /** * drm_bridge_pre_enable - calls 'pre_enable' drm_bridge_funcs op for all * bridges in the encoder chain. * @bridge: bridge control structure * * Calls 'pre_enable' drm_bridge_funcs op for all the bridges in the encoder * chain, starting from the last bridge to the first. These are called * before calling the encoder's commit op. * * Note: the bridge passed should be the one closest to the encoder */ void drm_bridge_pre_enable(struct drm_bridge *bridge) { if (!bridge) return; drm_bridge_pre_enable(bridge->next); bridge->funcs->pre_enable(bridge); } EXPORT_SYMBOL(drm_bridge_pre_enable); /** * drm_bridge_enable - calls 'enable' drm_bridge_funcs op for all bridges * in the encoder chain. * @bridge: bridge control structure * * Calls 'enable' drm_bridge_funcs op for all the bridges in the encoder * chain, starting from the first bridge to the last. These are called * after completing the encoder's commit op. * * Note that the bridge passed should be the one closest to the encoder */ void drm_bridge_enable(struct drm_bridge *bridge) { if (!bridge) return; bridge->funcs->enable(bridge); drm_bridge_enable(bridge->next); } EXPORT_SYMBOL(drm_bridge_enable); #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) { struct drm_bridge *bridge; mutex_lock(&bridge_lock); list_for_each_entry(bridge, &bridge_list, list) { if (bridge->of_node == np) { mutex_unlock(&bridge_lock); return bridge; } } mutex_unlock(&bridge_lock); return NULL; } EXPORT_SYMBOL(of_drm_find_bridge); #endif MODULE_AUTHOR("Ajay Kumar "); MODULE_DESCRIPTION("DRM bridge infrastructure"); MODULE_LICENSE("GPL and additional rights");