/*
* 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/module.h>
#include <drm/drm_crtc.h>
#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.
*/
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
*
* 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 <ajaykumar.rs@samsung.com>");
MODULE_DESCRIPTION("DRM bridge infrastructure");
MODULE_LICENSE("GPL and additional rights");
