gpu/drm/drm_panel.c

0001 /*
0002  * Copyright (C) 2013, NVIDIA Corporation.  All rights reserved.
0003  *
0004  * Permission is hereby granted, free of charge, to any person obtaining a
0005  * copy of this software and associated documentation files (the "Software"),
0006  * to deal in the Software without restriction, including without limitation
0007  * the rights to use, copy, modify, merge, publish, distribute, sub license,
0008  * and/or sell copies of the Software, and to permit persons to whom the
0009  * Software is furnished to do so, subject to the following conditions:
0010  *
0011  * The above copyright notice and this permission notice (including the
0012  * next paragraph) shall be included in all copies or substantial portions
0013  * of the Software.
0014  *
0015  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
0016  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
0017  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
0018  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
0019  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
0020  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
0021  * DEALINGS IN THE SOFTWARE.
0022  */
0023
0024 #include <linux/backlight.h>
0025 #include <linux/err.h>
0026 #include <linux/module.h>
0027
0028 #include <drm/drm_crtc.h>
0029 #include <drm/drm_panel.h>
0030 #include <drm/drm_print.h>
0031
0032 static DEFINE_MUTEX(panel_lock);
0033 static LIST_HEAD(panel_list);
0034
0035 /**
0036  * DOC: drm panel
0037  *
0038  * The DRM panel helpers allow drivers to register panel objects with a
0039  * central registry and provide functions to retrieve those panels in display
0040  * drivers.
0041  *
0042  * For easy integration into drivers using the &drm_bridge infrastructure please
0043  * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add().
0044  */
0045
0046 /**
0047  * drm_panel_init - initialize a panel
0048  * @panel: DRM panel
0049  * @dev: parent device of the panel
0050  * @funcs: panel operations
0051  * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to
0052  *  the panel interface
0053  *
0054  * Initialize the panel structure for subsequent registration with
0055  * drm_panel_add().
0056  */
0057 void drm_panel_init(struct drm_panel *panel, struct device *dev,
0058             const struct drm_panel_funcs *funcs, int connector_type)
0059 {
0060     INIT_LIST_HEAD(&panel->list);
0061     panel->dev = dev;
0062     panel->funcs = funcs;
0063     panel->connector_type = connector_type;
0064 }
0065 EXPORT_SYMBOL(drm_panel_init);
0066
0067 /**
0068  * drm_panel_add - add a panel to the global registry
0069  * @panel: panel to add
0070  *
0071  * Add a panel to the global registry so that it can be looked up by display
0072  * drivers.
0073  */
0074 void drm_panel_add(struct drm_panel *panel)
0075 {
0076     mutex_lock(&panel_lock);
0077     list_add_tail(&panel->list, &panel_list);
0078     mutex_unlock(&panel_lock);
0079 }
0080 EXPORT_SYMBOL(drm_panel_add);
0081
0082 /**
0083  * drm_panel_remove - remove a panel from the global registry
0084  * @panel: DRM panel
0085  *
0086  * Removes a panel from the global registry.
0087  */
0088 void drm_panel_remove(struct drm_panel *panel)
0089 {
0090     mutex_lock(&panel_lock);
0091     list_del_init(&panel->list);
0092     mutex_unlock(&panel_lock);
0093 }
0094 EXPORT_SYMBOL(drm_panel_remove);
0095
0096 /**
0097  * drm_panel_prepare - power on a panel
0098  * @panel: DRM panel
0099  *
0100  * Calling this function will enable power and deassert any reset signals to
0101  * the panel. After this has completed it is possible to communicate with any
0102  * integrated circuitry via a command bus.
0103  *
0104  * Return: 0 on success or a negative error code on failure.
0105  */
0106 int drm_panel_prepare(struct drm_panel *panel)
0107 {
0108     if (!panel)
0109         return -EINVAL;
0110
0111     if (panel->funcs && panel->funcs->prepare)
0112         return panel->funcs->prepare(panel);
0113
0114     return 0;
0115 }
0116 EXPORT_SYMBOL(drm_panel_prepare);
0117
0118 /**
0119  * drm_panel_unprepare - power off a panel
0120  * @panel: DRM panel
0121  *
0122  * Calling this function will completely power off a panel (assert the panel's
0123  * reset, turn off power supplies, ...). After this function has completed, it
0124  * is usually no longer possible to communicate with the panel until another
0125  * call to drm_panel_prepare().
0126  *
0127  * Return: 0 on success or a negative error code on failure.
0128  */
0129 int drm_panel_unprepare(struct drm_panel *panel)
0130 {
0131     if (!panel)
0132         return -EINVAL;
0133
0134     if (panel->funcs && panel->funcs->unprepare)
0135         return panel->funcs->unprepare(panel);
0136
0137     return 0;
0138 }
0139 EXPORT_SYMBOL(drm_panel_unprepare);
0140
0141 /**
0142  * drm_panel_enable - enable a panel
0143  * @panel: DRM panel
0144  *
0145  * Calling this function will cause the panel display drivers to be turned on
0146  * and the backlight to be enabled. Content will be visible on screen after
0147  * this call completes.
0148  *
0149  * Return: 0 on success or a negative error code on failure.
0150  */
0151 int drm_panel_enable(struct drm_panel *panel)
0152 {
0153     int ret;
0154
0155     if (!panel)
0156         return -EINVAL;
0157
0158     if (panel->funcs && panel->funcs->enable) {
0159         ret = panel->funcs->enable(panel);
0160         if (ret < 0)
0161             return ret;
0162     }
0163
0164     ret = backlight_enable(panel->backlight);
0165     if (ret < 0)
0166         DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",
0167                  ret);
0168
0169     return 0;
0170 }
0171 EXPORT_SYMBOL(drm_panel_enable);
0172
0173 /**
0174  * drm_panel_disable - disable a panel
0175  * @panel: DRM panel
0176  *
0177  * This will typically turn off the panel's backlight or disable the display
0178  * drivers. For smart panels it should still be possible to communicate with
0179  * the integrated circuitry via any command bus after this call.
0180  *
0181  * Return: 0 on success or a negative error code on failure.
0182  */
0183 int drm_panel_disable(struct drm_panel *panel)
0184 {
0185     int ret;
0186
0187     if (!panel)
0188         return -EINVAL;
0189
0190     ret = backlight_disable(panel->backlight);
0191     if (ret < 0)
0192         DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",
0193                  ret);
0194
0195     if (panel->funcs && panel->funcs->disable)
0196         return panel->funcs->disable(panel);
0197
0198     return 0;
0199 }
0200 EXPORT_SYMBOL(drm_panel_disable);
0201
0202 /**
0203  * drm_panel_get_modes - probe the available display modes of a panel
0204  * @panel: DRM panel
0205  * @connector: DRM connector
0206  *
0207  * The modes probed from the panel are automatically added to the connector
0208  * that the panel is attached to.
0209  *
0210  * Return: The number of modes available from the panel on success or a
0211  * negative error code on failure.
0212  */
0213 int drm_panel_get_modes(struct drm_panel *panel,
0214             struct drm_connector *connector)
0215 {
0216     if (!panel)
0217         return -EINVAL;
0218
0219     if (panel->funcs && panel->funcs->get_modes)
0220         return panel->funcs->get_modes(panel, connector);
0221
0222     return -EOPNOTSUPP;
0223 }
0224 EXPORT_SYMBOL(drm_panel_get_modes);
0225
0226 #ifdef CONFIG_OF
0227 /**
0228  * of_drm_find_panel - look up a panel using a device tree node
0229  * @np: device tree node of the panel
0230  *
0231  * Searches the set of registered panels for one that matches the given device
0232  * tree node. If a matching panel is found, return a pointer to it.
0233  *
0234  * Return: A pointer to the panel registered for the specified device tree
0235  * node or an ERR_PTR() if no panel matching the device tree node can be found.
0236  *
0237  * Possible error codes returned by this function:
0238  *
0239  * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
0240  *   should retry later
0241  * - ENODEV: the device is not available (status != "okay" or "ok")
0242  */
0243 struct drm_panel *of_drm_find_panel(const struct device_node *np)
0244 {
0245     struct drm_panel *panel;
0246
0247     if (!of_device_is_available(np))
0248         return ERR_PTR(-ENODEV);
0249
0250     mutex_lock(&panel_lock);
0251
0252     list_for_each_entry(panel, &panel_list, list) {
0253         if (panel->dev->of_node == np) {
0254             mutex_unlock(&panel_lock);
0255             return panel;
0256         }
0257     }
0258
0259     mutex_unlock(&panel_lock);
0260     return ERR_PTR(-EPROBE_DEFER);
0261 }
0262 EXPORT_SYMBOL(of_drm_find_panel);
0263
0264 /**
0265  * of_drm_get_panel_orientation - look up the orientation of the panel through
0266  * the "rotation" binding from a device tree node
0267  * @np: device tree node of the panel
0268  * @orientation: orientation enum to be filled in
0269  *
0270  * Looks up the rotation of a panel in the device tree. The orientation of the
0271  * panel is expressed as a property name "rotation" in the device tree. The
0272  * rotation in the device tree is counter clockwise.
0273  *
0274  * Return: 0 when a valid rotation value (0, 90, 180, or 270) is read or the
0275  * rotation property doesn't exist. Return a negative error code on failure.
0276  */
0277 int of_drm_get_panel_orientation(const struct device_node *np,
0278                  enum drm_panel_orientation *orientation)
0279 {
0280     int rotation, ret;
0281
0282     ret = of_property_read_u32(np, "rotation", &rotation);
0283     if (ret == -EINVAL) {
0284         /* Don't return an error if there's no rotation property. */
0285         *orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
0286         return 0;
0287     }
0288
0289     if (ret < 0)
0290         return ret;
0291
0292     if (rotation == 0)
0293         *orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL;
0294     else if (rotation == 90)
0295         *orientation = DRM_MODE_PANEL_ORIENTATION_RIGHT_UP;
0296     else if (rotation == 180)
0297         *orientation = DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP;
0298     else if (rotation == 270)
0299         *orientation = DRM_MODE_PANEL_ORIENTATION_LEFT_UP;
0300     else
0301         return -EINVAL;
0302
0303     return 0;
0304 }
0305 EXPORT_SYMBOL(of_drm_get_panel_orientation);
0306 #endif
0307
0308 #if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
0309 /**
0310  * drm_panel_of_backlight - use backlight device node for backlight
0311  * @panel: DRM panel
0312  *
0313  * Use this function to enable backlight handling if your panel
0314  * uses device tree and has a backlight phandle.
0315  *
0316  * When the panel is enabled backlight will be enabled after a
0317  * successful call to &drm_panel_funcs.enable()
0318  *
0319  * When the panel is disabled backlight will be disabled before the
0320  * call to &drm_panel_funcs.disable().
0321  *
0322  * A typical implementation for a panel driver supporting device tree
0323  * will call this function at probe time. Backlight will then be handled
0324  * transparently without requiring any intervention from the driver.
0325  * drm_panel_of_backlight() must be called after the call to drm_panel_init().
0326  *
0327  * Return: 0 on success or a negative error code on failure.
0328  */
0329 int drm_panel_of_backlight(struct drm_panel *panel)
0330 {
0331     struct backlight_device *backlight;
0332
0333     if (!panel || !panel->dev)
0334         return -EINVAL;
0335
0336     backlight = devm_of_find_backlight(panel->dev);
0337
0338     if (IS_ERR(backlight))
0339         return PTR_ERR(backlight);
0340
0341     panel->backlight = backlight;
0342     return 0;
0343 }
0344 EXPORT_SYMBOL(drm_panel_of_backlight);
0345 #endif
0346
0347 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
0348 MODULE_DESCRIPTION("DRM panel infrastructure");
0349 MODULE_LICENSE("GPL and additional rights");