/*
* 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 <linux/mutex.h>
#include <drm/drm_bridge.h>
#include <drm/drm_encoder.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 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 and hence are not visible to userspace. They
* just provide additional hooks to get the desired output at the end of the
* encoder chain.
*
* Bridges can also be chained up using the &drm_bridge.next pointer.
*
* Both legacy CRTC helpers and the new atomic modeset helpers support bridges.
*/
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)
{
mutex_lock(&bridge_lock);
list_add_tail(&bridge->list, &bridge_list);
mutex_unlock(&bridge_lock);
}
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 - attach the bridge to an encoder's chain
*
* @encoder: DRM encoder
* @bridge: bridge to attach
* @previous: previous bridge in the chain (optional)
*
* 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)
{
int ret;
if (!encoder || !bridge)
return -EINVAL;
if (previous && (!previous->dev || previous->encoder != encoder))
return -EINVAL;
if (bridge->dev)
return -EBUSY;
bridge->dev = encoder->dev;
bridge->encoder = encoder;
if (bridge->funcs->attach) {
ret = bridge->funcs->attach(bridge);
if (ret < 0) {
bridge->dev = NULL;
bridge->encoder = NULL;
return ret;
}
}
if (previous)
previous->next = bridge;
else
encoder->bridge = bridge;
return 0;
}
EXPORT_SYMBOL(drm_bridge_attach);
void drm_bridge_detach(struct drm_bridge *bridge)
{
if (WARN_ON(!bridge))
return;
if (WARN_ON(!bridge->dev))
return;
if (bridge->funcs->detach)
bridge->funcs->detach(bridge);
bridge->dev = NULL;
}
/**
* 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.
*
* For detailed specification of the bridge callbacks see &drm_bridge_funcs.
*/
/**
* 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 &drm_bridge_funcs.mode_fixup 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_mode_valid - validate the mode against all bridges in the
* encoder chain.
* @bridge: bridge control structure
* @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_mode_valid(struct drm_bridge *bridge,
const struct drm_display_mode *mode)
{
enum drm_mode_status ret = MODE_OK;
if (!bridge)
return ret;
if (bridge->funcs->mode_valid)
ret = bridge->funcs->mode_valid(bridge, mode);
if (ret != MODE_OK)
return ret;
return drm_bridge_mode_valid(bridge->next, mode);
}
EXPORT_SYMBOL(drm_bridge_mode_valid);
/**
* drm_bridge_disable - disables all bridges in the encoder chain
* @bridge: bridge control structure
*
* Calls &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 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);
if (bridge->funcs->disable)
bridge->funcs->disable(bridge);
}
EXPORT_SYMBOL(drm_bridge_disable);
/**
* drm_bridge_post_disable - cleans up after disabling all bridges in the encoder chain
* @bridge: bridge control structure
*
* Calls &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 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;
if (bridge->funcs->post_disable)
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 &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_mode_set(struct drm_bridge *bridge,
const struct drm_display_mode *mode,
const 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 - prepares for enabling all
* bridges in the encoder chain
* @bridge: bridge control structure
*
* Calls &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 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);
if (bridge->funcs->pre_enable)
bridge->funcs->pre_enable(bridge);
}
EXPORT_SYMBOL(drm_bridge_pre_enable);
/**
* drm_bridge_enable - enables all bridges in the encoder chain
* @bridge: bridge control structure
*
* Calls &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 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;
if (bridge->funcs->enable)
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");
