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Diffstat (limited to 'drivers/gpu/drm/drm_panel.c')
| -rw-r--r-- | drivers/gpu/drm/drm_panel.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c new file mode 100644 index 000000000..1d9a9d2fe --- /dev/null +++ b/drivers/gpu/drm/drm_panel.c @@ -0,0 +1,174 @@ +/* + * 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. + */ + +/** + * 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->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) +{ + 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"); |