drivers/gpu/drm/drm_panel.c - linux - Git at Google

 /*
  * 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_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.
  *
  * For easy integration into drivers using the &drm_bridge infrastructure please
  * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add().
  */

 /**
  * drm_panel_init - initialize a panel
  * @panel: DRM panel
  * @dev: parent device of the panel
  * @funcs: panel operations
  * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to
  *	the panel interface
  *
  * Initialize the panel structure for subsequent registration with
  * drm_panel_add().
  */
 void drm_panel_init(struct drm_panel *panel, struct device *dev,
 		    const struct drm_panel_funcs *funcs, int connector_type)
 {
 	INIT_LIST_HEAD(&panel->list);
 	panel->dev = dev;
 	panel->funcs = funcs;
 	panel->connector_type = connector_type;
 }
 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->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().
  */
 void drm_panel_detach(struct drm_panel *panel)
 {
 	panel->connector = NULL;
 	panel->drm = NULL;
 }
 EXPORT_SYMBOL(drm_panel_detach);

 /**
  * drm_panel_prepare - power on a panel
  * @panel: DRM panel
  *
  * Calling this function will enable power and deassert any reset signals to
  * the panel. After this has completed it is possible to communicate with any
  * integrated circuitry via a command bus.
  *
  * Return: 0 on success or a negative error code on failure.
  */
 int drm_panel_prepare(struct drm_panel *panel)
 {
 	if (panel && panel->funcs && panel->funcs->prepare)
 		return panel->funcs->prepare(panel);

 	return panel ? -ENOSYS : -EINVAL;
 }
 EXPORT_SYMBOL(drm_panel_prepare);

 /**
  * drm_panel_unprepare - power off a panel
  * @panel: DRM panel
  *
  * Calling this function will completely power off a panel (assert the panel's
  * reset, turn off power supplies, ...). After this function has completed, it
  * is usually no longer possible to communicate with the panel until another
  * call to drm_panel_prepare().
  *
  * Return: 0 on success or a negative error code on failure.
  */
 int drm_panel_unprepare(struct drm_panel *panel)
 {
 	if (panel && panel->funcs && panel->funcs->unprepare)
 		return panel->funcs->unprepare(panel);

 	return panel ? -ENOSYS : -EINVAL;
 }
 EXPORT_SYMBOL(drm_panel_unprepare);

 /**
  * drm_panel_enable - enable a panel
  * @panel: DRM panel
  *
  * Calling this function will cause the panel display drivers to be turned on
  * and the backlight to be enabled. Content will be visible on screen after
  * this call completes.
  *
  * Return: 0 on success or a negative error code on failure.
  */
 int drm_panel_enable(struct drm_panel *panel)
 {
 	if (panel && panel->funcs && panel->funcs->enable)
 		return panel->funcs->enable(panel);

 	return panel ? -ENOSYS : -EINVAL;
 }
 EXPORT_SYMBOL(drm_panel_enable);

 /**
  * drm_panel_disable - disable a panel
  * @panel: DRM panel
  *
  * This will typically turn off the panel's backlight or disable the display
  * drivers. For smart panels it should still be possible to communicate with
  * the integrated circuitry via any command bus after this call.
  *
  * Return: 0 on success or a negative error code on failure.
  */
 int drm_panel_disable(struct drm_panel *panel)
 {
 	if (panel && panel->funcs && panel->funcs->disable)
 		return panel->funcs->disable(panel);

 	return panel ? -ENOSYS : -EINVAL;
 }
 EXPORT_SYMBOL(drm_panel_disable);

 /**
  * drm_panel_get_modes - probe the available display modes of a panel
  * @panel: DRM panel
  *
  * The modes probed from the panel are automatically added to the connector
  * that the panel is attached to.
  *
  * Return: The number of modes available from the panel on success or a
  * negative error code on failure.
  */
 int drm_panel_get_modes(struct drm_panel *panel)
 {
 	if (panel && panel->funcs && panel->funcs->get_modes)
 		return panel->funcs->get_modes(panel);

 	return panel ? -ENOSYS : -EINVAL;
 }
 EXPORT_SYMBOL(drm_panel_get_modes);

 #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");
	/*
	* 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_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.
	*
	* For easy integration into drivers using the &drm_bridge infrastructure please
	* take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add().
	*/

	/**
	* drm_panel_init - initialize a panel
	* @panel: DRM panel
	* @dev: parent device of the panel
	* @funcs: panel operations
	* @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to
	* the panel interface
	*
	* Initialize the panel structure for subsequent registration with
	* drm_panel_add().
	*/
	void drm_panel_init(struct drm_panel panel, struct device dev,
	const struct drm_panel_funcs *funcs, int connector_type)
	{
	INIT_LIST_HEAD(&panel->list);
	panel->dev = dev;
	panel->funcs = funcs;
	panel->connector_type = connector_type;
	}
	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->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().
	*/
	void drm_panel_detach(struct drm_panel *panel)
	{
	panel->connector = NULL;
	panel->drm = NULL;
	}
	EXPORT_SYMBOL(drm_panel_detach);

	/**
	* drm_panel_prepare - power on a panel
	* @panel: DRM panel
	*
	* Calling this function will enable power and deassert any reset signals to
	* the panel. After this has completed it is possible to communicate with any
	* integrated circuitry via a command bus.
	*
	* Return: 0 on success or a negative error code on failure.
	*/
	int drm_panel_prepare(struct drm_panel *panel)
	{
	if (panel && panel->funcs && panel->funcs->prepare)
	return panel->funcs->prepare(panel);

	return panel ? -ENOSYS : -EINVAL;
	}
	EXPORT_SYMBOL(drm_panel_prepare);

	/**
	* drm_panel_unprepare - power off a panel
	* @panel: DRM panel
	*
	* Calling this function will completely power off a panel (assert the panel's
	* reset, turn off power supplies, ...). After this function has completed, it
	* is usually no longer possible to communicate with the panel until another
	* call to drm_panel_prepare().
	*
	* Return: 0 on success or a negative error code on failure.
	*/
	int drm_panel_unprepare(struct drm_panel *panel)
	{
	if (panel && panel->funcs && panel->funcs->unprepare)
	return panel->funcs->unprepare(panel);

	return panel ? -ENOSYS : -EINVAL;
	}
	EXPORT_SYMBOL(drm_panel_unprepare);

	/**
	* drm_panel_enable - enable a panel
	* @panel: DRM panel
	*
	* Calling this function will cause the panel display drivers to be turned on
	* and the backlight to be enabled. Content will be visible on screen after
	* this call completes.
	*
	* Return: 0 on success or a negative error code on failure.
	*/
	int drm_panel_enable(struct drm_panel *panel)
	{
	if (panel && panel->funcs && panel->funcs->enable)
	return panel->funcs->enable(panel);

	return panel ? -ENOSYS : -EINVAL;
	}
	EXPORT_SYMBOL(drm_panel_enable);

	/**
	* drm_panel_disable - disable a panel
	* @panel: DRM panel
	*
	* This will typically turn off the panel's backlight or disable the display
	* drivers. For smart panels it should still be possible to communicate with
	* the integrated circuitry via any command bus after this call.
	*
	* Return: 0 on success or a negative error code on failure.
	*/
	int drm_panel_disable(struct drm_panel *panel)
	{
	if (panel && panel->funcs && panel->funcs->disable)
	return panel->funcs->disable(panel);

	return panel ? -ENOSYS : -EINVAL;
	}
	EXPORT_SYMBOL(drm_panel_disable);

	/**
	* drm_panel_get_modes - probe the available display modes of a panel
	* @panel: DRM panel
	*
	* The modes probed from the panel are automatically added to the connector
	* that the panel is attached to.
	*
	* Return: The number of modes available from the panel on success or a
	* negative error code on failure.
	*/
	int drm_panel_get_modes(struct drm_panel *panel)
	{
	if (panel && panel->funcs && panel->funcs->get_modes)
	return panel->funcs->get_modes(panel);

	return panel ? -ENOSYS : -EINVAL;
	}
	EXPORT_SYMBOL(drm_panel_get_modes);

	#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");