2 * Copyright (C) 2013, NVIDIA Corporation. All rights reserved.
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:
11 * The above copyright notice and this permission notice (including the
12 * next paragraph) shall be included in all copies or substantial portions
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.
24 #include <linux/backlight.h>
25 #include <linux/err.h>
26 #include <linux/module.h>
28 #include <drm/drm_crtc.h>
29 #include <drm/drm_panel.h>
30 #include <drm/drm_print.h>
32 static DEFINE_MUTEX(panel_lock);
33 static LIST_HEAD(panel_list);
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
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().
47 * drm_panel_init - initialize a panel
49 * @dev: parent device of the panel
50 * @funcs: panel operations
51 * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to
54 * Initialize the panel structure for subsequent registration with
57 void drm_panel_init(struct drm_panel *panel, struct device *dev,
58 const struct drm_panel_funcs *funcs, int connector_type)
60 INIT_LIST_HEAD(&panel->list);
63 panel->connector_type = connector_type;
65 EXPORT_SYMBOL(drm_panel_init);
68 * drm_panel_add - add a panel to the global registry
69 * @panel: panel to add
71 * Add a panel to the global registry so that it can be looked up by display
74 void drm_panel_add(struct drm_panel *panel)
76 mutex_lock(&panel_lock);
77 list_add_tail(&panel->list, &panel_list);
78 mutex_unlock(&panel_lock);
80 EXPORT_SYMBOL(drm_panel_add);
83 * drm_panel_remove - remove a panel from the global registry
86 * Removes a panel from the global registry.
88 void drm_panel_remove(struct drm_panel *panel)
90 mutex_lock(&panel_lock);
91 list_del_init(&panel->list);
92 mutex_unlock(&panel_lock);
94 EXPORT_SYMBOL(drm_panel_remove);
97 * drm_panel_attach - attach a panel to a connector
99 * @connector: DRM connector
101 * After obtaining a pointer to a DRM panel a display driver calls this
102 * function to attach a panel to a connector.
104 * An error is returned if the panel is already attached to another connector.
106 * When unloading, the driver should detach from the panel by calling
107 * drm_panel_detach().
109 * Return: 0 on success or a negative error code on failure.
111 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector)
115 EXPORT_SYMBOL(drm_panel_attach);
118 * drm_panel_detach - detach a panel from a connector
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.
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().
127 void drm_panel_detach(struct drm_panel *panel)
130 EXPORT_SYMBOL(drm_panel_detach);
133 * drm_panel_prepare - power on a panel
136 * Calling this function will enable power and deassert any reset signals to
137 * the panel. After this has completed it is possible to communicate with any
138 * integrated circuitry via a command bus.
140 * Return: 0 on success or a negative error code on failure.
142 int drm_panel_prepare(struct drm_panel *panel)
147 if (panel->funcs && panel->funcs->prepare)
148 return panel->funcs->prepare(panel);
152 EXPORT_SYMBOL(drm_panel_prepare);
155 * drm_panel_unprepare - power off a panel
158 * Calling this function will completely power off a panel (assert the panel's
159 * reset, turn off power supplies, ...). After this function has completed, it
160 * is usually no longer possible to communicate with the panel until another
161 * call to drm_panel_prepare().
163 * Return: 0 on success or a negative error code on failure.
165 int drm_panel_unprepare(struct drm_panel *panel)
170 if (panel->funcs && panel->funcs->unprepare)
171 return panel->funcs->unprepare(panel);
175 EXPORT_SYMBOL(drm_panel_unprepare);
178 * drm_panel_enable - enable a panel
181 * Calling this function will cause the panel display drivers to be turned on
182 * and the backlight to be enabled. Content will be visible on screen after
183 * this call completes.
185 * Return: 0 on success or a negative error code on failure.
187 int drm_panel_enable(struct drm_panel *panel)
194 if (panel->funcs && panel->funcs->enable) {
195 ret = panel->funcs->enable(panel);
200 ret = backlight_enable(panel->backlight);
202 DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",
207 EXPORT_SYMBOL(drm_panel_enable);
210 * drm_panel_disable - disable a panel
213 * This will typically turn off the panel's backlight or disable the display
214 * drivers. For smart panels it should still be possible to communicate with
215 * the integrated circuitry via any command bus after this call.
217 * Return: 0 on success or a negative error code on failure.
219 int drm_panel_disable(struct drm_panel *panel)
226 ret = backlight_disable(panel->backlight);
228 DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",
231 if (panel->funcs && panel->funcs->disable)
232 return panel->funcs->disable(panel);
236 EXPORT_SYMBOL(drm_panel_disable);
239 * drm_panel_get_modes - probe the available display modes of a panel
241 * @connector: DRM connector
243 * The modes probed from the panel are automatically added to the connector
244 * that the panel is attached to.
246 * Return: The number of modes available from the panel on success or a
247 * negative error code on failure.
249 int drm_panel_get_modes(struct drm_panel *panel,
250 struct drm_connector *connector)
255 if (panel->funcs && panel->funcs->get_modes)
256 return panel->funcs->get_modes(panel, connector);
260 EXPORT_SYMBOL(drm_panel_get_modes);
264 * of_drm_find_panel - look up a panel using a device tree node
265 * @np: device tree node of the panel
267 * Searches the set of registered panels for one that matches the given device
268 * tree node. If a matching panel is found, return a pointer to it.
270 * Return: A pointer to the panel registered for the specified device tree
271 * node or an ERR_PTR() if no panel matching the device tree node can be found.
273 * Possible error codes returned by this function:
275 * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
277 * - ENODEV: the device is not available (status != "okay" or "ok")
279 struct drm_panel *of_drm_find_panel(const struct device_node *np)
281 struct drm_panel *panel;
283 if (!of_device_is_available(np))
284 return ERR_PTR(-ENODEV);
286 mutex_lock(&panel_lock);
288 list_for_each_entry(panel, &panel_list, list) {
289 if (panel->dev->of_node == np) {
290 mutex_unlock(&panel_lock);
295 mutex_unlock(&panel_lock);
296 return ERR_PTR(-EPROBE_DEFER);
298 EXPORT_SYMBOL(of_drm_find_panel);
301 #if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
303 * drm_panel_of_backlight - use backlight device node for backlight
306 * Use this function to enable backlight handling if your panel
307 * uses device tree and has a backlight phandle.
309 * When the panel is enabled backlight will be enabled after a
310 * successful call to &drm_panel_funcs.enable()
312 * When the panel is disabled backlight will be disabled before the
313 * call to &drm_panel_funcs.disable().
315 * A typical implementation for a panel driver supporting device tree
316 * will call this function at probe time. Backlight will then be handled
317 * transparently without requiring any intervention from the driver.
318 * drm_panel_of_backlight() must be called after the call to drm_panel_init().
320 * Return: 0 on success or a negative error code on failure.
322 int drm_panel_of_backlight(struct drm_panel *panel)
324 struct backlight_device *backlight;
326 if (!panel || !panel->dev)
329 backlight = devm_of_find_backlight(panel->dev);
331 if (IS_ERR(backlight))
332 return PTR_ERR(backlight);
334 panel->backlight = backlight;
337 EXPORT_SYMBOL(drm_panel_of_backlight);
340 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
341 MODULE_DESCRIPTION("DRM panel infrastructure");
342 MODULE_LICENSE("GPL and additional rights");