1 /* 2 * Copyright (C) 2013, NVIDIA Corporation. All rights reserved. 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sub license, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the 12 * next paragraph) shall be included in all copies or substantial portions 13 * of the Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 21 * DEALINGS IN THE SOFTWARE. 22 */ 23 24 #include <linux/err.h> 25 #include <linux/module.h> 26 27 #include <drm/drm_crtc.h> 28 #include <drm/drm_panel.h> 29 30 static DEFINE_MUTEX(panel_lock); 31 static LIST_HEAD(panel_list); 32 33 /** 34 * DOC: drm panel 35 * 36 * The DRM panel helpers allow drivers to register panel objects with a 37 * central registry and provide functions to retrieve those panels in display 38 * drivers. 39 */ 40 41 /** 42 * drm_panel_init - initialize a panel 43 * @panel: DRM panel 44 * 45 * Sets up internal fields of the panel so that it can subsequently be added 46 * to the registry. 47 */ 48 void drm_panel_init(struct drm_panel *panel) 49 { 50 INIT_LIST_HEAD(&panel->list); 51 } 52 EXPORT_SYMBOL(drm_panel_init); 53 54 /** 55 * drm_panel_add - add a panel to the global registry 56 * @panel: panel to add 57 * 58 * Add a panel to the global registry so that it can be looked up by display 59 * drivers. 60 * 61 * Return: 0 on success or a negative error code on failure. 62 */ 63 int drm_panel_add(struct drm_panel *panel) 64 { 65 mutex_lock(&panel_lock); 66 list_add_tail(&panel->list, &panel_list); 67 mutex_unlock(&panel_lock); 68 69 return 0; 70 } 71 EXPORT_SYMBOL(drm_panel_add); 72 73 /** 74 * drm_panel_remove - remove a panel from the global registry 75 * @panel: DRM panel 76 * 77 * Removes a panel from the global registry. 78 */ 79 void drm_panel_remove(struct drm_panel *panel) 80 { 81 mutex_lock(&panel_lock); 82 list_del_init(&panel->list); 83 mutex_unlock(&panel_lock); 84 } 85 EXPORT_SYMBOL(drm_panel_remove); 86 87 /** 88 * drm_panel_attach - attach a panel to a connector 89 * @panel: DRM panel 90 * @connector: DRM connector 91 * 92 * After obtaining a pointer to a DRM panel a display driver calls this 93 * function to attach a panel to a connector. 94 * 95 * An error is returned if the panel is already attached to another connector. 96 * 97 * Return: 0 on success or a negative error code on failure. 98 */ 99 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector) 100 { 101 if (panel->connector) 102 return -EBUSY; 103 104 panel->connector = connector; 105 panel->drm = connector->dev; 106 107 return 0; 108 } 109 EXPORT_SYMBOL(drm_panel_attach); 110 111 /** 112 * drm_panel_detach - detach a panel from a connector 113 * @panel: DRM panel 114 * 115 * Detaches a panel from the connector it is attached to. If a panel is not 116 * attached to any connector this is effectively a no-op. 117 * 118 * Return: 0 on success or a negative error code on failure. 119 */ 120 int drm_panel_detach(struct drm_panel *panel) 121 { 122 panel->connector = NULL; 123 panel->drm = NULL; 124 125 return 0; 126 } 127 EXPORT_SYMBOL(drm_panel_detach); 128 129 #ifdef CONFIG_OF 130 /** 131 * of_drm_find_panel - look up a panel using a device tree node 132 * @np: device tree node of the panel 133 * 134 * Searches the set of registered panels for one that matches the given device 135 * tree node. If a matching panel is found, return a pointer to it. 136 * 137 * Return: A pointer to the panel registered for the specified device tree 138 * node or NULL if no panel matching the device tree node can be found. 139 */ 140 struct drm_panel *of_drm_find_panel(const struct device_node *np) 141 { 142 struct drm_panel *panel; 143 144 mutex_lock(&panel_lock); 145 146 list_for_each_entry(panel, &panel_list, list) { 147 if (panel->dev->of_node == np) { 148 mutex_unlock(&panel_lock); 149 return panel; 150 } 151 } 152 153 mutex_unlock(&panel_lock); 154 return NULL; 155 } 156 EXPORT_SYMBOL(of_drm_find_panel); 157 #endif 158 159 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>"); 160 MODULE_DESCRIPTION("DRM panel infrastructure"); 161 MODULE_LICENSE("GPL and additional rights"); 162