drivers/gpu/drm/drm_panel.c

   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/backlight.h>
  25 #include <linux/err.h>
  26 #include <linux/module.h>
  27
  28 #include <drm/drm_crtc.h>
  29 #include <drm/drm_panel.h>
  30 #include <drm/drm_print.h>
  31
  32 static DEFINE_MUTEX(panel_lock);
  33 static LIST_HEAD(panel_list);
  34
  35 /**
  36  * DOC: drm panel
  37  *
  38  * The DRM panel helpers allow drivers to register panel objects with a
  39  * central registry and provide functions to retrieve those panels in display
  40  * drivers.
  41  *
  42  * For easy integration into drivers using the &drm_bridge infrastructure please
  43  * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add().
  44  */
  45
  46 /**
  47  * drm_panel_init - initialize a panel
  48  * @panel: DRM panel
  49  * @dev: parent device of the panel
  50  * @funcs: panel operations
  51  * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to
  52  *      the panel interface
  53  *
  54  * Initialize the panel structure for subsequent registration with
  55  * drm_panel_add().
  56  */
  57 void drm_panel_init(struct drm_panel *panel, struct device *dev,
  58                     const struct drm_panel_funcs *funcs, int connector_type)
  59 {
  60         INIT_LIST_HEAD(&panel->list);
  61         panel->dev = dev;
  62         panel->funcs = funcs;
  63         panel->connector_type = connector_type;
  64 }
  65 EXPORT_SYMBOL(drm_panel_init);
  66
  67 /**
  68  * drm_panel_add - add a panel to the global registry
  69  * @panel: panel to add
  70  *
  71  * Add a panel to the global registry so that it can be looked up by display
  72  * drivers.
  73  *
  74  * Return: 0 on success or a negative error code on failure.
  75  */
  76 int drm_panel_add(struct drm_panel *panel)
  77 {
  78         mutex_lock(&panel_lock);
  79         list_add_tail(&panel->list, &panel_list);
  80         mutex_unlock(&panel_lock);
  81
  82         return 0;
  83 }
  84 EXPORT_SYMBOL(drm_panel_add);
  85
  86 /**
  87  * drm_panel_remove - remove a panel from the global registry
  88  * @panel: DRM panel
  89  *
  90  * Removes a panel from the global registry.
  91  */
  92 void drm_panel_remove(struct drm_panel *panel)
  93 {
  94         mutex_lock(&panel_lock);
  95         list_del_init(&panel->list);
  96         mutex_unlock(&panel_lock);
  97 }
  98 EXPORT_SYMBOL(drm_panel_remove);
  99
 100 /**
 101  * drm_panel_attach - attach a panel to a connector
 102  * @panel: DRM panel
 103  * @connector: DRM connector
 104  *
 105  * After obtaining a pointer to a DRM panel a display driver calls this
 106  * function to attach a panel to a connector.
 107  *
 108  * An error is returned if the panel is already attached to another connector.
 109  *
 110  * When unloading, the driver should detach from the panel by calling
 111  * drm_panel_detach().
 112  *
 113  * Return: 0 on success or a negative error code on failure.
 114  */
 115 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector)
 116 {
 117         return 0;
 118 }
 119 EXPORT_SYMBOL(drm_panel_attach);
 120
 121 /**
 122  * drm_panel_detach - detach a panel from a connector
 123  * @panel: DRM panel
 124  *
 125  * Detaches a panel from the connector it is attached to. If a panel is not
 126  * attached to any connector this is effectively a no-op.
 127  *
 128  * This function should not be called by the panel device itself. It
 129  * is only for the drm device that called drm_panel_attach().
 130  */
 131 void drm_panel_detach(struct drm_panel *panel)
 132 {
 133 }
 134 EXPORT_SYMBOL(drm_panel_detach);
 135
 136 /**
 137  * drm_panel_prepare - power on a panel
 138  * @panel: DRM panel
 139  *
 140  * Calling this function will enable power and deassert any reset signals to
 141  * the panel. After this has completed it is possible to communicate with any
 142  * integrated circuitry via a command bus.
 143  *
 144  * Return: 0 on success or a negative error code on failure.
 145  */
 146 int drm_panel_prepare(struct drm_panel *panel)
 147 {
 148         if (!panel)
 149                 return -EINVAL;
 150
 151         if (panel->funcs && panel->funcs->prepare)
 152                 return panel->funcs->prepare(panel);
 153
 154         return 0;
 155 }
 156 EXPORT_SYMBOL(drm_panel_prepare);
 157
 158 /**
 159  * drm_panel_unprepare - power off a panel
 160  * @panel: DRM panel
 161  *
 162  * Calling this function will completely power off a panel (assert the panel's
 163  * reset, turn off power supplies, ...). After this function has completed, it
 164  * is usually no longer possible to communicate with the panel until another
 165  * call to drm_panel_prepare().
 166  *
 167  * Return: 0 on success or a negative error code on failure.
 168  */
 169 int drm_panel_unprepare(struct drm_panel *panel)
 170 {
 171         if (!panel)
 172                 return -EINVAL;
 173
 174         if (panel->funcs && panel->funcs->unprepare)
 175                 return panel->funcs->unprepare(panel);
 176
 177         return 0;
 178 }
 179 EXPORT_SYMBOL(drm_panel_unprepare);
 180
 181 /**
 182  * drm_panel_enable - enable a panel
 183  * @panel: DRM panel
 184  *
 185  * Calling this function will cause the panel display drivers to be turned on
 186  * and the backlight to be enabled. Content will be visible on screen after
 187  * this call completes.
 188  *
 189  * Return: 0 on success or a negative error code on failure.
 190  */
 191 int drm_panel_enable(struct drm_panel *panel)
 192 {
 193         int ret;
 194
 195         if (!panel)
 196                 return -EINVAL;
 197
 198         if (panel->funcs && panel->funcs->enable) {
 199                 ret = panel->funcs->enable(panel);
 200                 if (ret < 0)
 201                         return ret;
 202         }
 203
 204         ret = backlight_enable(panel->backlight);
 205         if (ret < 0)
 206                 DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",
 207                              ret);
 208
 209         return 0;
 210 }
 211 EXPORT_SYMBOL(drm_panel_enable);
 212
 213 /**
 214  * drm_panel_disable - disable a panel
 215  * @panel: DRM panel
 216  *
 217  * This will typically turn off the panel's backlight or disable the display
 218  * drivers. For smart panels it should still be possible to communicate with
 219  * the integrated circuitry via any command bus after this call.
 220  *
 221  * Return: 0 on success or a negative error code on failure.
 222  */
 223 int drm_panel_disable(struct drm_panel *panel)
 224 {
 225         int ret;
 226
 227         if (!panel)
 228                 return -EINVAL;
 229
 230         ret = backlight_disable(panel->backlight);
 231         if (ret < 0)
 232                 DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",
 233                              ret);
 234
 235         if (panel->funcs && panel->funcs->disable)
 236                 return panel->funcs->disable(panel);
 237
 238         return 0;
 239 }
 240 EXPORT_SYMBOL(drm_panel_disable);
 241
 242 /**
 243  * drm_panel_get_modes - probe the available display modes of a panel
 244  * @panel: DRM panel
 245  * @connector: DRM connector
 246  *
 247  * The modes probed from the panel are automatically added to the connector
 248  * that the panel is attached to.
 249  *
 250  * Return: The number of modes available from the panel on success or a
 251  * negative error code on failure.
 252  */
 253 int drm_panel_get_modes(struct drm_panel *panel,
 254                         struct drm_connector *connector)
 255 {
 256         if (!panel)
 257                 return -EINVAL;
 258
 259         if (panel->funcs && panel->funcs->get_modes)
 260                 return panel->funcs->get_modes(panel, connector);
 261
 262         return -EOPNOTSUPP;
 263 }
 264 EXPORT_SYMBOL(drm_panel_get_modes);
 265
 266 #ifdef CONFIG_OF
 267 /**
 268  * of_drm_find_panel - look up a panel using a device tree node
 269  * @np: device tree node of the panel
 270  *
 271  * Searches the set of registered panels for one that matches the given device
 272  * tree node. If a matching panel is found, return a pointer to it.
 273  *
 274  * Return: A pointer to the panel registered for the specified device tree
 275  * node or an ERR_PTR() if no panel matching the device tree node can be found.
 276  *
 277  * Possible error codes returned by this function:
 278  *
 279  * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
 280  *   should retry later
 281  * - ENODEV: the device is not available (status != "okay" or "ok")
 282  */
 283 struct drm_panel *of_drm_find_panel(const struct device_node *np)
 284 {
 285         struct drm_panel *panel;
 286
 287         if (!of_device_is_available(np))
 288                 return ERR_PTR(-ENODEV);
 289
 290         mutex_lock(&panel_lock);
 291
 292         list_for_each_entry(panel, &panel_list, list) {
 293                 if (panel->dev->of_node == np) {
 294                         mutex_unlock(&panel_lock);
 295                         return panel;
 296                 }
 297         }
 298
 299         mutex_unlock(&panel_lock);
 300         return ERR_PTR(-EPROBE_DEFER);
 301 }
 302 EXPORT_SYMBOL(of_drm_find_panel);
 303 #endif
 304
 305 #if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
 306 /**
 307  * drm_panel_of_backlight - use backlight device node for backlight
 308  * @panel: DRM panel
 309  *
 310  * Use this function to enable backlight handling if your panel
 311  * uses device tree and has a backlight phandle.
 312  *
 313  * When the panel is enabled backlight will be enabled after a
 314  * successful call to &drm_panel_funcs.enable()
 315  *
 316  * When the panel is disabled backlight will be disabled before the
 317  * call to &drm_panel_funcs.disable().
 318  *
 319  * A typical implementation for a panel driver supporting device tree
 320  * will call this function at probe time. Backlight will then be handled
 321  * transparently without requiring any intervention from the driver.
 322  * drm_panel_of_backlight() must be called after the call to drm_panel_init().
 323  *
 324  * Return: 0 on success or a negative error code on failure.
 325  */
 326 int drm_panel_of_backlight(struct drm_panel *panel)
 327 {
 328         struct backlight_device *backlight;
 329
 330         if (!panel || !panel->dev)
 331                 return -EINVAL;
 332
 333         backlight = devm_of_find_backlight(panel->dev);
 334
 335         if (IS_ERR(backlight))
 336                 return PTR_ERR(backlight);
 337
 338         panel->backlight = backlight;
 339         return 0;
 340 }
 341 EXPORT_SYMBOL(drm_panel_of_backlight);
 342 #endif
 343
 344 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
 345 MODULE_DESCRIPTION("DRM panel infrastructure");
 346 MODULE_LICENSE("GPL and additional rights");