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 * For easy integration into drivers using the &drm_bridge infrastructure please 41 * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add(). 42 */ 43 44 /** 45 * drm_panel_init - initialize a panel 46 * @panel: DRM panel 47 * 48 * Sets up internal fields of the panel so that it can subsequently be added 49 * to the registry. 50 */ 51 void drm_panel_init(struct drm_panel *panel) 52 { 53 INIT_LIST_HEAD(&panel->list); 54 } 55 EXPORT_SYMBOL(drm_panel_init); 56 57 /** 58 * drm_panel_add - add a panel to the global registry 59 * @panel: panel to add 60 * 61 * Add a panel to the global registry so that it can be looked up by display 62 * drivers. 63 * 64 * Return: 0 on success or a negative error code on failure. 65 */ 66 int drm_panel_add(struct drm_panel *panel) 67 { 68 mutex_lock(&panel_lock); 69 list_add_tail(&panel->list, &panel_list); 70 mutex_unlock(&panel_lock); 71 72 return 0; 73 } 74 EXPORT_SYMBOL(drm_panel_add); 75 76 /** 77 * drm_panel_remove - remove a panel from the global registry 78 * @panel: DRM panel 79 * 80 * Removes a panel from the global registry. 81 */ 82 void drm_panel_remove(struct drm_panel *panel) 83 { 84 mutex_lock(&panel_lock); 85 list_del_init(&panel->list); 86 mutex_unlock(&panel_lock); 87 } 88 EXPORT_SYMBOL(drm_panel_remove); 89 90 /** 91 * drm_panel_attach - attach a panel to a connector 92 * @panel: DRM panel 93 * @connector: DRM connector 94 * 95 * After obtaining a pointer to a DRM panel a display driver calls this 96 * function to attach a panel to a connector. 97 * 98 * An error is returned if the panel is already attached to another connector. 99 * 100 * When unloading, the driver should detach from the panel by calling 101 * drm_panel_detach(). 102 * 103 * Return: 0 on success or a negative error code on failure. 104 */ 105 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector) 106 { 107 if (panel->connector) 108 return -EBUSY; 109 110 panel->connector = connector; 111 panel->drm = connector->dev; 112 113 return 0; 114 } 115 EXPORT_SYMBOL(drm_panel_attach); 116 117 /** 118 * drm_panel_detach - detach a panel from a connector 119 * @panel: DRM panel 120 * 121 * Detaches a panel from the connector it is attached to. If a panel is not 122 * attached to any connector this is effectively a no-op. 123 * 124 * This function should not be called by the panel device itself. It 125 * is only for the drm device that called drm_panel_attach(). 126 * 127 * Return: 0 on success or a negative error code on failure. 128 */ 129 int drm_panel_detach(struct drm_panel *panel) 130 { 131 panel->connector = NULL; 132 panel->drm = NULL; 133 134 return 0; 135 } 136 EXPORT_SYMBOL(drm_panel_detach); 137 138 #ifdef CONFIG_OF 139 /** 140 * of_drm_find_panel - look up a panel using a device tree node 141 * @np: device tree node of the panel 142 * 143 * Searches the set of registered panels for one that matches the given device 144 * tree node. If a matching panel is found, return a pointer to it. 145 * 146 * Return: A pointer to the panel registered for the specified device tree 147 * node or an ERR_PTR() if no panel matching the device tree node can be found. 148 * 149 * Possible error codes returned by this function: 150 * 151 * - EPROBE_DEFER: the panel device has not been probed yet, and the caller 152 * should retry later 153 * - ENODEV: the device is not available (status != "okay" or "ok") 154 */ 155 struct drm_panel *of_drm_find_panel(const struct device_node *np) 156 { 157 struct drm_panel *panel; 158 159 if (!of_device_is_available(np)) 160 return ERR_PTR(-ENODEV); 161 162 mutex_lock(&panel_lock); 163 164 list_for_each_entry(panel, &panel_list, list) { 165 if (panel->dev->of_node == np) { 166 mutex_unlock(&panel_lock); 167 return panel; 168 } 169 } 170 171 mutex_unlock(&panel_lock); 172 return ERR_PTR(-EPROBE_DEFER); 173 } 174 EXPORT_SYMBOL(of_drm_find_panel); 175 #endif 176 177 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>"); 178 MODULE_DESCRIPTION("DRM panel infrastructure"); 179 MODULE_LICENSE("GPL and additional rights"); 180