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/*
* Copyright (C) 2013, NVIDIA Corporation. All rights reserved.
*
* 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_device.h>
#include <drm/drm_crtc.h>
#include <drm/drm_panel.h>
static DEFINE_MUTEX(panel_lock);
static LIST_HEAD(panel_list);
/**
* DOC: drm panel
*
* The DRM panel helpers allow drivers to register panel objects with a
* central registry and provide functions to retrieve those panels in display
* drivers.
*/
/**
* drm_panel_init - initialize a panel
* @panel: DRM panel
*
* Sets up internal fields of the panel so that it can subsequently be added
* to the registry.
*/
void drm_panel_init(struct drm_panel *panel)
{
INIT_LIST_HEAD(&panel->list);
}
EXPORT_SYMBOL(drm_panel_init);
/**
* drm_panel_add - add a panel to the global registry
* @panel: panel to add
*
* Add a panel to the global registry so that it can be looked up by display
* drivers.
*
* Return: 0 on success or a negative error code on failure.
*/
int drm_panel_add(struct drm_panel *panel)
{
mutex_lock(&panel_lock);
list_add_tail(&panel->list, &panel_list);
mutex_unlock(&panel_lock);
return 0;
}
EXPORT_SYMBOL(drm_panel_add);
/**
* drm_panel_remove - remove a panel from the global registry
* @panel: DRM panel
*
* Removes a panel from the global registry.
*/
void drm_panel_remove(struct drm_panel *panel)
{
mutex_lock(&panel_lock);
list_del_init(&panel->list);
mutex_unlock(&panel_lock);
}
EXPORT_SYMBOL(drm_panel_remove);
/**
* drm_panel_attach - attach a panel to a connector
* @panel: DRM panel
* @connector: DRM connector
*
* After obtaining a pointer to a DRM panel a display driver calls this
* function to attach a panel to a connector.
*
* An error is returned if the panel is already attached to another connector.
*
* When unloading, the driver should detach from the panel by calling
* drm_panel_detach().
*
* Return: 0 on success or a negative error code on failure.
*/
int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector)
{
if (panel->connector)
return -EBUSY;
panel->link = device_link_add(connector->dev->dev, panel->dev, 0);
if (!panel->link) {
dev_err(panel->dev, "failed to link panel to %s\n",
dev_name(connector->dev->dev));
return -EINVAL;
}
panel->connector = connector;
panel->drm = connector->dev;
return 0;
}
EXPORT_SYMBOL(drm_panel_attach);
/**
* drm_panel_detach - detach a panel from a connector
* @panel: DRM panel
*
* Detaches a panel from the connector it is attached to. If a panel is not
* attached to any connector this is effectively a no-op.
*
* This function should not be called by the panel device itself. It
* is only for the drm device that called drm_panel_attach().
*
* Return: 0 on success or a negative error code on failure.
*/
int drm_panel_detach(struct drm_panel *panel)
{
device_link_del(panel->link);
panel->connector = NULL;
panel->drm = NULL;
return 0;
}
EXPORT_SYMBOL(drm_panel_detach);
#ifdef CONFIG_OF
/**
* of_drm_find_panel - look up a panel using a device tree node
* @np: device tree node of the panel
*
* Searches the set of registered panels for one that matches the given device
* tree node. If a matching panel is found, return a pointer to it.
*
* Return: A pointer to the panel registered for the specified device tree
* node or an ERR_PTR() if no panel matching the device tree node can be found.
*
* Possible error codes returned by this function:
*
* - EPROBE_DEFER: the panel device has not been probed yet, and the caller
* should retry later
* - ENODEV: the device is not available (status != "okay" or "ok")
*/
struct drm_panel *of_drm_find_panel(const struct device_node *np)
{
struct drm_panel *panel;
if (!of_device_is_available(np))
return ERR_PTR(-ENODEV);
mutex_lock(&panel_lock);
list_for_each_entry(panel, &panel_list, list) {
if (panel->dev->of_node == np) {
mutex_unlock(&panel_lock);
return panel;
}
}
mutex_unlock(&panel_lock);
return ERR_PTR(-EPROBE_DEFER);
}
EXPORT_SYMBOL(of_drm_find_panel);
#endif
MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
MODULE_DESCRIPTION("DRM panel infrastructure");
MODULE_LICENSE("GPL and additional rights");
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