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/err.h>
25 #include <linux/module.h>
26
27 #include <drm/drm_crtc.h>
28 #include <drm/drm_panel.h>
29
30 static DEFINE_MUTEX(panel_lock);
31 static LIST_HEAD(panel_list);
32
33 /**
34 * DOC: drm panel
35 *
36 * The DRM panel helpers allow drivers to register panel objects with a
37 * central registry and provide functions to retrieve those panels in display
38 * drivers.
39 *
40 * For easy integration into drivers using the &drm_bridge infrastructure please
41 * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add().
42 */
43
44 /**
45 * drm_panel_init - initialize a panel
46 * @panel: DRM panel
47 *
48 * Sets up internal fields of the panel so that it can subsequently be added
49 * to the registry.
50 */
51 void drm_panel_init(struct drm_panel *panel)
52 {
53 INIT_LIST_HEAD(&panel->list);
54 }
55 EXPORT_SYMBOL(drm_panel_init);
56
57 /**
58 * drm_panel_add - add a panel to the global registry
59 * @panel: panel to add
60 *
61 * Add a panel to the global registry so that it can be looked up by display
62 * drivers.
63 *
64 * Return: 0 on success or a negative error code on failure.
65 */
66 int drm_panel_add(struct drm_panel *panel)
67 {
68 mutex_lock(&panel_lock);
69 list_add_tail(&panel->list, &panel_list);
70 mutex_unlock(&panel_lock);
71
72 return 0;
73 }
74 EXPORT_SYMBOL(drm_panel_add);
75
76 /**
77 * drm_panel_remove - remove a panel from the global registry
78 * @panel: DRM panel
79 *
80 * Removes a panel from the global registry.
81 */
82 void drm_panel_remove(struct drm_panel *panel)
83 {
84 mutex_lock(&panel_lock);
85 list_del_init(&panel->list);
86 mutex_unlock(&panel_lock);
87 }
88 EXPORT_SYMBOL(drm_panel_remove);
89
90 /**
91 * drm_panel_attach - attach a panel to a connector
92 * @panel: DRM panel
93 * @connector: DRM connector
94 *
95 * After obtaining a pointer to a DRM panel a display driver calls this
96 * function to attach a panel to a connector.
97 *
98 * An error is returned if the panel is already attached to another connector.
99 *
100 * When unloading, the driver should detach from the panel by calling
101 * drm_panel_detach().
102 *
103 * Return: 0 on success or a negative error code on failure.
104 */
105 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector)
106 {
107 if (panel->connector)
108 return -EBUSY;
109
110 panel->connector = connector;
111 panel->drm = connector->dev;
112
113 return 0;
114 }
115 EXPORT_SYMBOL(drm_panel_attach);
116
117 /**
118 * drm_panel_detach - detach a panel from a connector
119 * @panel: DRM panel
120 *
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.
123 *
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().
126 */
127 void drm_panel_detach(struct drm_panel *panel)
128 {
129 panel->connector = NULL;
130 panel->drm = NULL;
131 }
132 EXPORT_SYMBOL(drm_panel_detach);
133
134 /**
135 * drm_panel_prepare - power on a panel
136 * @panel: DRM panel
137 *
138 * Calling this function will enable power and deassert any reset signals to
139 * the panel. After this has completed it is possible to communicate with any
140 * integrated circuitry via a command bus.
141 *
142 * Return: 0 on success or a negative error code on failure.
143 */
144 int drm_panel_prepare(struct drm_panel *panel)
145 {
146 if (panel && panel->funcs && panel->funcs->prepare)
147 return panel->funcs->prepare(panel);
148
149 return panel ? -ENOSYS : -EINVAL;
150 }
151 EXPORT_SYMBOL(drm_panel_prepare);
152
153 /**
154 * drm_panel_unprepare - power off a panel
155 * @panel: DRM panel
156 *
157 * Calling this function will completely power off a panel (assert the panel's
158 * reset, turn off power supplies, ...). After this function has completed, it
159 * is usually no longer possible to communicate with the panel until another
160 * call to drm_panel_prepare().
161 *
162 * Return: 0 on success or a negative error code on failure.
163 */
164 int drm_panel_unprepare(struct drm_panel *panel)
165 {
166 if (panel && panel->funcs && panel->funcs->unprepare)
167 return panel->funcs->unprepare(panel);
168
169 return panel ? -ENOSYS : -EINVAL;
170 }
171 EXPORT_SYMBOL(drm_panel_unprepare);
172
173 /**
174 * drm_panel_enable - enable a panel
175 * @panel: DRM panel
176 *
177 * Calling this function will cause the panel display drivers to be turned on
178 * and the backlight to be enabled. Content will be visible on screen after
179 * this call completes.
180 *
181 * Return: 0 on success or a negative error code on failure.
182 */
183 int drm_panel_enable(struct drm_panel *panel)
184 {
185 if (panel && panel->funcs && panel->funcs->enable)
186 return panel->funcs->enable(panel);
187
188 return panel ? -ENOSYS : -EINVAL;
189 }
190 EXPORT_SYMBOL(drm_panel_enable);
191
192 /**
193 * drm_panel_disable - disable a panel
194 * @panel: DRM panel
195 *
196 * This will typically turn off the panel's backlight or disable the display
197 * drivers. For smart panels it should still be possible to communicate with
198 * the integrated circuitry via any command bus after this call.
199 *
200 * Return: 0 on success or a negative error code on failure.
201 */
202 int drm_panel_disable(struct drm_panel *panel)
203 {
204 if (panel && panel->funcs && panel->funcs->disable)
205 return panel->funcs->disable(panel);
206
207 return panel ? -ENOSYS : -EINVAL;
208 }
209 EXPORT_SYMBOL(drm_panel_disable);
210
211 /**
212 * drm_panel_get_modes - probe the available display modes of a panel
213 * @panel: DRM panel
214 *
215 * The modes probed from the panel are automatically added to the connector
216 * that the panel is attached to.
217 *
218 * Return: The number of modes available from the panel on success or a
219 * negative error code on failure.
220 */
221 int drm_panel_get_modes(struct drm_panel *panel)
222 {
223 if (panel && panel->funcs && panel->funcs->get_modes)
224 return panel->funcs->get_modes(panel);
225
226 return panel ? -ENOSYS : -EINVAL;
227 }
228 EXPORT_SYMBOL(drm_panel_get_modes);
229
230 #ifdef CONFIG_OF
231 /**
232 * of_drm_find_panel - look up a panel using a device tree node
233 * @np: device tree node of the panel
234 *
235 * Searches the set of registered panels for one that matches the given device
236 * tree node. If a matching panel is found, return a pointer to it.
237 *
238 * Return: A pointer to the panel registered for the specified device tree
239 * node or an ERR_PTR() if no panel matching the device tree node can be found.
240 *
241 * Possible error codes returned by this function:
242 *
243 * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
244 * should retry later
245 * - ENODEV: the device is not available (status != "okay" or "ok")
246 */
247 struct drm_panel *of_drm_find_panel(const struct device_node *np)
248 {
249 struct drm_panel *panel;
250
251 if (!of_device_is_available(np))
252 return ERR_PTR(-ENODEV);
253
254 mutex_lock(&panel_lock);
255
256 list_for_each_entry(panel, &panel_list, list) {
257 if (panel->dev->of_node == np) {
258 mutex_unlock(&panel_lock);
259 return panel;
260 }
261 }
262
263 mutex_unlock(&panel_lock);
264 return ERR_PTR(-EPROBE_DEFER);
265 }
266 EXPORT_SYMBOL(of_drm_find_panel);
267 #endif
268
269 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
270 MODULE_DESCRIPTION("DRM panel infrastructure");
271 MODULE_LICENSE("GPL and additional rights");