2 * Copyright (C) 2013, NVIDIA Corporation. All rights reserved.
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11 * The above copyright notice and this permission notice (including the
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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 panel->orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
66 of_drm_get_panel_orientation(dev->of_node, &panel->orientation);
68 EXPORT_SYMBOL(drm_panel_init);
71 * drm_panel_add - add a panel to the global registry
72 * @panel: panel to add
74 * Add a panel to the global registry so that it can be looked up by display
77 void drm_panel_add(struct drm_panel *panel)
79 mutex_lock(&panel_lock);
80 list_add_tail(&panel->list, &panel_list);
81 mutex_unlock(&panel_lock);
83 EXPORT_SYMBOL(drm_panel_add);
86 * drm_panel_remove - remove a panel from the global registry
89 * Removes a panel from the global registry.
91 void drm_panel_remove(struct drm_panel *panel)
93 mutex_lock(&panel_lock);
94 list_del_init(&panel->list);
95 mutex_unlock(&panel_lock);
97 EXPORT_SYMBOL(drm_panel_remove);
100 * drm_panel_prepare - power on a panel
103 * Calling this function will enable power and deassert any reset signals to
104 * the panel. After this has completed it is possible to communicate with any
105 * integrated circuitry via a command bus.
107 * Return: 0 on success or a negative error code on failure.
109 int drm_panel_prepare(struct drm_panel *panel)
114 if (panel->funcs && panel->funcs->prepare)
115 return panel->funcs->prepare(panel);
119 EXPORT_SYMBOL(drm_panel_prepare);
122 * drm_panel_unprepare - power off a panel
125 * Calling this function will completely power off a panel (assert the panel's
126 * reset, turn off power supplies, ...). After this function has completed, it
127 * is usually no longer possible to communicate with the panel until another
128 * call to drm_panel_prepare().
130 * Return: 0 on success or a negative error code on failure.
132 int drm_panel_unprepare(struct drm_panel *panel)
137 if (panel->funcs && panel->funcs->unprepare)
138 return panel->funcs->unprepare(panel);
142 EXPORT_SYMBOL(drm_panel_unprepare);
145 * drm_panel_enable - enable a panel
148 * Calling this function will cause the panel display drivers to be turned on
149 * and the backlight to be enabled. Content will be visible on screen after
150 * this call completes.
152 * Return: 0 on success or a negative error code on failure.
154 int drm_panel_enable(struct drm_panel *panel)
161 if (panel->funcs && panel->funcs->enable) {
162 ret = panel->funcs->enable(panel);
167 ret = backlight_enable(panel->backlight);
169 DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",
174 EXPORT_SYMBOL(drm_panel_enable);
177 * drm_panel_disable - disable a panel
180 * This will typically turn off the panel's backlight or disable the display
181 * drivers. For smart panels it should still be possible to communicate with
182 * the integrated circuitry via any command bus after this call.
184 * Return: 0 on success or a negative error code on failure.
186 int drm_panel_disable(struct drm_panel *panel)
193 ret = backlight_disable(panel->backlight);
195 DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",
198 if (panel->funcs && panel->funcs->disable)
199 return panel->funcs->disable(panel);
203 EXPORT_SYMBOL(drm_panel_disable);
206 * drm_panel_get_modes - probe the available display modes of a panel
208 * @connector: DRM connector
210 * The modes probed from the panel are automatically added to the connector
211 * that the panel is attached to.
213 * Return: The number of modes available from the panel on success or a
214 * negative error code on failure.
216 int drm_panel_get_modes(struct drm_panel *panel,
217 struct drm_connector *connector)
222 if (panel->funcs && panel->funcs->get_modes)
223 return panel->funcs->get_modes(panel, connector);
227 EXPORT_SYMBOL(drm_panel_get_modes);
231 * of_drm_find_panel - look up a panel using a device tree node
232 * @np: device tree node of the panel
234 * Searches the set of registered panels for one that matches the given device
235 * tree node. If a matching panel is found, return a pointer to it.
237 * Return: A pointer to the panel registered for the specified device tree
238 * node or an ERR_PTR() if no panel matching the device tree node can be found.
240 * Possible error codes returned by this function:
242 * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
244 * - ENODEV: the device is not available (status != "okay" or "ok")
246 struct drm_panel *of_drm_find_panel(const struct device_node *np)
248 struct drm_panel *panel;
250 if (!of_device_is_available(np))
251 return ERR_PTR(-ENODEV);
253 mutex_lock(&panel_lock);
255 list_for_each_entry(panel, &panel_list, list) {
256 if (panel->dev->of_node == np) {
257 mutex_unlock(&panel_lock);
262 mutex_unlock(&panel_lock);
263 return ERR_PTR(-EPROBE_DEFER);
265 EXPORT_SYMBOL(of_drm_find_panel);
268 * of_drm_get_panel_orientation - look up the orientation of the panel through
269 * the "rotation" binding from a device tree node
270 * @np: device tree node of the panel
271 * @orientation: orientation enum to be filled in
273 * Looks up the rotation of a panel in the device tree. The orientation of the
274 * panel is expressed as a property name "rotation" in the device tree. The
275 * rotation in the device tree is counter clockwise.
277 * Return: 0 when a valid rotation value (0, 90, 180, or 270) is read or the
278 * rotation property doesn't exist. Return a negative error code on failure.
280 int of_drm_get_panel_orientation(const struct device_node *np,
281 enum drm_panel_orientation *orientation)
285 ret = of_property_read_u32(np, "rotation", &rotation);
286 if (ret == -EINVAL) {
287 /* Don't return an error if there's no rotation property. */
288 *orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
296 *orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL;
297 } else if (rotation == 90) {
298 *orientation = DRM_MODE_PANEL_ORIENTATION_RIGHT_UP;
299 } else if (rotation == 180) {
300 *orientation = DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP;
301 } else if (rotation == 270) {
302 *orientation = DRM_MODE_PANEL_ORIENTATION_LEFT_UP;
304 DRM_ERROR("%pOF: invalid orientation %d\n", np, ret);
310 EXPORT_SYMBOL(of_drm_get_panel_orientation);
313 #if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
315 * drm_panel_of_backlight - use backlight device node for backlight
318 * Use this function to enable backlight handling if your panel
319 * uses device tree and has a backlight phandle.
321 * When the panel is enabled backlight will be enabled after a
322 * successful call to &drm_panel_funcs.enable()
324 * When the panel is disabled backlight will be disabled before the
325 * call to &drm_panel_funcs.disable().
327 * A typical implementation for a panel driver supporting device tree
328 * will call this function at probe time. Backlight will then be handled
329 * transparently without requiring any intervention from the driver.
330 * drm_panel_of_backlight() must be called after the call to drm_panel_init().
332 * Return: 0 on success or a negative error code on failure.
334 int drm_panel_of_backlight(struct drm_panel *panel)
336 struct backlight_device *backlight;
338 if (!panel || !panel->dev)
341 backlight = devm_of_find_backlight(panel->dev);
343 if (IS_ERR(backlight))
344 return PTR_ERR(backlight);
346 panel->backlight = backlight;
349 EXPORT_SYMBOL(drm_panel_of_backlight);
352 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
353 MODULE_DESCRIPTION("DRM panel infrastructure");
354 MODULE_LICENSE("GPL and additional rights");