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 void drm_panel_add(struct drm_panel *panel)
  75 {
  76         mutex_lock(&panel_lock);
  77         list_add_tail(&panel->list, &panel_list);
  78         mutex_unlock(&panel_lock);
  79 }
  80 EXPORT_SYMBOL(drm_panel_add);
  81
  82 /**
  83  * drm_panel_remove - remove a panel from the global registry
  84  * @panel: DRM panel
  85  *
  86  * Removes a panel from the global registry.
  87  */
  88 void drm_panel_remove(struct drm_panel *panel)
  89 {
  90         mutex_lock(&panel_lock);
  91         list_del_init(&panel->list);
  92         mutex_unlock(&panel_lock);
  93 }
  94 EXPORT_SYMBOL(drm_panel_remove);
  95
  96 /**
  97  * drm_panel_prepare - power on a panel
  98  * @panel: DRM panel
  99  *
 100  * Calling this function will enable power and deassert any reset signals to
 101  * the panel. After this has completed it is possible to communicate with any
 102  * integrated circuitry via a command bus.
 103  *
 104  * Return: 0 on success or a negative error code on failure.
 105  */
 106 int drm_panel_prepare(struct drm_panel *panel)
 107 {
 108         if (!panel)
 109                 return -EINVAL;
 110
 111         if (panel->funcs && panel->funcs->prepare)
 112                 return panel->funcs->prepare(panel);
 113
 114         return 0;
 115 }
 116 EXPORT_SYMBOL(drm_panel_prepare);
 117
 118 /**
 119  * drm_panel_unprepare - power off a panel
 120  * @panel: DRM panel
 121  *
 122  * Calling this function will completely power off a panel (assert the panel's
 123  * reset, turn off power supplies, ...). After this function has completed, it
 124  * is usually no longer possible to communicate with the panel until another
 125  * call to drm_panel_prepare().
 126  *
 127  * Return: 0 on success or a negative error code on failure.
 128  */
 129 int drm_panel_unprepare(struct drm_panel *panel)
 130 {
 131         if (!panel)
 132                 return -EINVAL;
 133
 134         if (panel->funcs && panel->funcs->unprepare)
 135                 return panel->funcs->unprepare(panel);
 136
 137         return 0;
 138 }
 139 EXPORT_SYMBOL(drm_panel_unprepare);
 140
 141 /**
 142  * drm_panel_enable - enable a panel
 143  * @panel: DRM panel
 144  *
 145  * Calling this function will cause the panel display drivers to be turned on
 146  * and the backlight to be enabled. Content will be visible on screen after
 147  * this call completes.
 148  *
 149  * Return: 0 on success or a negative error code on failure.
 150  */
 151 int drm_panel_enable(struct drm_panel *panel)
 152 {
 153         int ret;
 154
 155         if (!panel)
 156                 return -EINVAL;
 157
 158         if (panel->funcs && panel->funcs->enable) {
 159                 ret = panel->funcs->enable(panel);
 160                 if (ret < 0)
 161                         return ret;
 162         }
 163
 164         ret = backlight_enable(panel->backlight);
 165         if (ret < 0)
 166                 DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",
 167                              ret);
 168
 169         return 0;
 170 }
 171 EXPORT_SYMBOL(drm_panel_enable);
 172
 173 /**
 174  * drm_panel_disable - disable a panel
 175  * @panel: DRM panel
 176  *
 177  * This will typically turn off the panel's backlight or disable the display
 178  * drivers. For smart panels it should still be possible to communicate with
 179  * the integrated circuitry via any command bus after this call.
 180  *
 181  * Return: 0 on success or a negative error code on failure.
 182  */
 183 int drm_panel_disable(struct drm_panel *panel)
 184 {
 185         int ret;
 186
 187         if (!panel)
 188                 return -EINVAL;
 189
 190         ret = backlight_disable(panel->backlight);
 191         if (ret < 0)
 192                 DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",
 193                              ret);
 194
 195         if (panel->funcs && panel->funcs->disable)
 196                 return panel->funcs->disable(panel);
 197
 198         return 0;
 199 }
 200 EXPORT_SYMBOL(drm_panel_disable);
 201
 202 /**
 203  * drm_panel_get_modes - probe the available display modes of a panel
 204  * @panel: DRM panel
 205  * @connector: DRM connector
 206  *
 207  * The modes probed from the panel are automatically added to the connector
 208  * that the panel is attached to.
 209  *
 210  * Return: The number of modes available from the panel on success or a
 211  * negative error code on failure.
 212  */
 213 int drm_panel_get_modes(struct drm_panel *panel,
 214                         struct drm_connector *connector)
 215 {
 216         if (!panel)
 217                 return -EINVAL;
 218
 219         if (panel->funcs && panel->funcs->get_modes)
 220                 return panel->funcs->get_modes(panel, connector);
 221
 222         return -EOPNOTSUPP;
 223 }
 224 EXPORT_SYMBOL(drm_panel_get_modes);
 225
 226 #ifdef CONFIG_OF
 227 /**
 228  * of_drm_find_panel - look up a panel using a device tree node
 229  * @np: device tree node of the panel
 230  *
 231  * Searches the set of registered panels for one that matches the given device
 232  * tree node. If a matching panel is found, return a pointer to it.
 233  *
 234  * Return: A pointer to the panel registered for the specified device tree
 235  * node or an ERR_PTR() if no panel matching the device tree node can be found.
 236  *
 237  * Possible error codes returned by this function:
 238  *
 239  * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
 240  *   should retry later
 241  * - ENODEV: the device is not available (status != "okay" or "ok")
 242  */
 243 struct drm_panel *of_drm_find_panel(const struct device_node *np)
 244 {
 245         struct drm_panel *panel;
 246
 247         if (!of_device_is_available(np))
 248                 return ERR_PTR(-ENODEV);
 249
 250         mutex_lock(&panel_lock);
 251
 252         list_for_each_entry(panel, &panel_list, list) {
 253                 if (panel->dev->of_node == np) {
 254                         mutex_unlock(&panel_lock);
 255                         return panel;
 256                 }
 257         }
 258
 259         mutex_unlock(&panel_lock);
 260         return ERR_PTR(-EPROBE_DEFER);
 261 }
 262 EXPORT_SYMBOL(of_drm_find_panel);
 263
 264 /**
 265  * of_drm_get_panel_orientation - look up the orientation of the panel through
 266  * the "rotation" binding from a device tree node
 267  * @np: device tree node of the panel
 268  * @orientation: orientation enum to be filled in
 269  *
 270  * Looks up the rotation of a panel in the device tree. The orientation of the
 271  * panel is expressed as a property name "rotation" in the device tree. The
 272  * rotation in the device tree is counter clockwise.
 273  *
 274  * Return: 0 when a valid rotation value (0, 90, 180, or 270) is read or the
 275  * rotation property doesn't exist. Return a negative error code on failure.
 276  */
 277 int of_drm_get_panel_orientation(const struct device_node *np,
 278                                  enum drm_panel_orientation *orientation)
 279 {
 280         int rotation, ret;
 281
 282         ret = of_property_read_u32(np, "rotation", &rotation);
 283         if (ret == -EINVAL) {
 284                 /* Don't return an error if there's no rotation property. */
 285                 *orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
 286                 return 0;
 287         }
 288
 289         if (ret < 0)
 290                 return ret;
 291
 292         if (rotation == 0)
 293                 *orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL;
 294         else if (rotation == 90)
 295                 *orientation = DRM_MODE_PANEL_ORIENTATION_RIGHT_UP;
 296         else if (rotation == 180)
 297                 *orientation = DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP;
 298         else if (rotation == 270)
 299                 *orientation = DRM_MODE_PANEL_ORIENTATION_LEFT_UP;
 300         else
 301                 return -EINVAL;
 302
 303         return 0;
 304 }
 305 EXPORT_SYMBOL(of_drm_get_panel_orientation);
 306 #endif
 307
 308 #if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
 309 /**
 310  * drm_panel_of_backlight - use backlight device node for backlight
 311  * @panel: DRM panel
 312  *
 313  * Use this function to enable backlight handling if your panel
 314  * uses device tree and has a backlight phandle.
 315  *
 316  * When the panel is enabled backlight will be enabled after a
 317  * successful call to &drm_panel_funcs.enable()
 318  *
 319  * When the panel is disabled backlight will be disabled before the
 320  * call to &drm_panel_funcs.disable().
 321  *
 322  * A typical implementation for a panel driver supporting device tree
 323  * will call this function at probe time. Backlight will then be handled
 324  * transparently without requiring any intervention from the driver.
 325  * drm_panel_of_backlight() must be called after the call to drm_panel_init().
 326  *
 327  * Return: 0 on success or a negative error code on failure.
 328  */
 329 int drm_panel_of_backlight(struct drm_panel *panel)
 330 {
 331         struct backlight_device *backlight;
 332
 333         if (!panel || !panel->dev)
 334                 return -EINVAL;
 335
 336         backlight = devm_of_find_backlight(panel->dev);
 337
 338         if (IS_ERR(backlight))
 339                 return PTR_ERR(backlight);
 340
 341         panel->backlight = backlight;
 342         return 0;
 343 }
 344 EXPORT_SYMBOL(drm_panel_of_backlight);
 345 #endif
 346
 347 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
 348 MODULE_DESCRIPTION("DRM panel infrastructure");
 349 MODULE_LICENSE("GPL and additional rights");