1 /* $NetBSD: drm_panel.c,v 1.5 2021/12/18 23:44:57 riastradh Exp $ */
2
3 /*
4 * Copyright (C) 2013, NVIDIA Corporation. All rights reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sub license,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice (including the
14 * next paragraph) shall be included in all copies or substantial portions
15 * of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
22 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
23 * DEALINGS IN THE SOFTWARE.
24 */
25
26 #include <sys/cdefs.h>
27 __KERNEL_RCSID(0, "$NetBSD: drm_panel.c,v 1.5 2021/12/18 23:44:57 riastradh Exp $");
28
29 #include <linux/backlight.h>
30 #include <linux/err.h>
31 #include <linux/module.h>
32
33 #include <drm/drm_crtc.h>
34 #include <drm/drm_panel.h>
35 #include <drm/drm_print.h>
36
37 #ifdef __NetBSD__
38 static struct mutex panel_lock;
39 static struct list_head panel_list = LIST_HEAD_INIT(panel_list);
40 #else
41 static DEFINE_MUTEX(panel_lock);
42 static LIST_HEAD(panel_list);
43 #endif
44
45 #ifdef __NetBSD__
drm_panel_init_lock(void)46 void drm_panel_init_lock(void)
47 {
48 linux_mutex_init(&panel_lock);
49 }
drm_panel_fini_lock(void)50 void drm_panel_fini_lock(void)
51 {
52 linux_mutex_destroy(&panel_lock);
53 }
54 #endif
55
56 /**
57 * DOC: drm panel
58 *
59 * The DRM panel helpers allow drivers to register panel objects with a
60 * central registry and provide functions to retrieve those panels in display
61 * drivers.
62 *
63 * For easy integration into drivers using the &drm_bridge infrastructure please
64 * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add().
65 */
66
67 /**
68 * drm_panel_init - initialize a panel
69 * @panel: DRM panel
70 * @dev: parent device of the panel
71 * @funcs: panel operations
72 * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to
73 * the panel interface
74 *
75 * Initialize the panel structure for subsequent registration with
76 * drm_panel_add().
77 */
drm_panel_init(struct drm_panel * panel,struct device * dev,const struct drm_panel_funcs * funcs,int connector_type)78 void drm_panel_init(struct drm_panel *panel, struct device *dev,
79 const struct drm_panel_funcs *funcs, int connector_type)
80 {
81 INIT_LIST_HEAD(&panel->list);
82 panel->dev = dev;
83 panel->funcs = funcs;
84 panel->connector_type = connector_type;
85 }
86 EXPORT_SYMBOL(drm_panel_init);
87
88 /**
89 * drm_panel_add - add a panel to the global registry
90 * @panel: panel to add
91 *
92 * Add a panel to the global registry so that it can be looked up by display
93 * drivers.
94 *
95 * Return: 0 on success or a negative error code on failure.
96 */
drm_panel_add(struct drm_panel * panel)97 int drm_panel_add(struct drm_panel *panel)
98 {
99 mutex_lock(&panel_lock);
100 list_add_tail(&panel->list, &panel_list);
101 mutex_unlock(&panel_lock);
102
103 return 0;
104 }
105 EXPORT_SYMBOL(drm_panel_add);
106
107 /**
108 * drm_panel_remove - remove a panel from the global registry
109 * @panel: DRM panel
110 *
111 * Removes a panel from the global registry.
112 */
drm_panel_remove(struct drm_panel * panel)113 void drm_panel_remove(struct drm_panel *panel)
114 {
115 mutex_lock(&panel_lock);
116 list_del_init(&panel->list);
117 mutex_unlock(&panel_lock);
118 }
119 EXPORT_SYMBOL(drm_panel_remove);
120
121 /**
122 * drm_panel_attach - attach a panel to a connector
123 * @panel: DRM panel
124 * @connector: DRM connector
125 *
126 * After obtaining a pointer to a DRM panel a display driver calls this
127 * function to attach a panel to a connector.
128 *
129 * An error is returned if the panel is already attached to another connector.
130 *
131 * When unloading, the driver should detach from the panel by calling
132 * drm_panel_detach().
133 *
134 * Return: 0 on success or a negative error code on failure.
135 */
drm_panel_attach(struct drm_panel * panel,struct drm_connector * connector)136 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector)
137 {
138 return 0;
139 }
140 EXPORT_SYMBOL(drm_panel_attach);
141
142 /**
143 * drm_panel_detach - detach a panel from a connector
144 * @panel: DRM panel
145 *
146 * Detaches a panel from the connector it is attached to. If a panel is not
147 * attached to any connector this is effectively a no-op.
148 *
149 * This function should not be called by the panel device itself. It
150 * is only for the drm device that called drm_panel_attach().
151 */
drm_panel_detach(struct drm_panel * panel)152 void drm_panel_detach(struct drm_panel *panel)
153 {
154 }
155 EXPORT_SYMBOL(drm_panel_detach);
156
157 /**
158 * drm_panel_prepare - power on a panel
159 * @panel: DRM panel
160 *
161 * Calling this function will enable power and deassert any reset signals to
162 * the panel. After this has completed it is possible to communicate with any
163 * integrated circuitry via a command bus.
164 *
165 * Return: 0 on success or a negative error code on failure.
166 */
drm_panel_prepare(struct drm_panel * panel)167 int drm_panel_prepare(struct drm_panel *panel)
168 {
169 if (!panel)
170 return -EINVAL;
171
172 if (panel->funcs && panel->funcs->prepare)
173 return panel->funcs->prepare(panel);
174
175 return 0;
176 }
177 EXPORT_SYMBOL(drm_panel_prepare);
178
179 /**
180 * drm_panel_unprepare - power off a panel
181 * @panel: DRM panel
182 *
183 * Calling this function will completely power off a panel (assert the panel's
184 * reset, turn off power supplies, ...). After this function has completed, it
185 * is usually no longer possible to communicate with the panel until another
186 * call to drm_panel_prepare().
187 *
188 * Return: 0 on success or a negative error code on failure.
189 */
drm_panel_unprepare(struct drm_panel * panel)190 int drm_panel_unprepare(struct drm_panel *panel)
191 {
192 if (!panel)
193 return -EINVAL;
194
195 if (panel->funcs && panel->funcs->unprepare)
196 return panel->funcs->unprepare(panel);
197
198 return 0;
199 }
200 EXPORT_SYMBOL(drm_panel_unprepare);
201
202 /**
203 * drm_panel_enable - enable a panel
204 * @panel: DRM panel
205 *
206 * Calling this function will cause the panel display drivers to be turned on
207 * and the backlight to be enabled. Content will be visible on screen after
208 * this call completes.
209 *
210 * Return: 0 on success or a negative error code on failure.
211 */
drm_panel_enable(struct drm_panel * panel)212 int drm_panel_enable(struct drm_panel *panel)
213 {
214 int ret;
215
216 if (!panel)
217 return -EINVAL;
218
219 if (panel->funcs && panel->funcs->enable) {
220 ret = panel->funcs->enable(panel);
221 if (ret < 0)
222 return ret;
223 }
224
225 ret = backlight_enable(panel->backlight);
226 if (ret < 0)
227 DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",
228 ret);
229
230 return 0;
231 }
232 EXPORT_SYMBOL(drm_panel_enable);
233
234 /**
235 * drm_panel_disable - disable a panel
236 * @panel: DRM panel
237 *
238 * This will typically turn off the panel's backlight or disable the display
239 * drivers. For smart panels it should still be possible to communicate with
240 * the integrated circuitry via any command bus after this call.
241 *
242 * Return: 0 on success or a negative error code on failure.
243 */
drm_panel_disable(struct drm_panel * panel)244 int drm_panel_disable(struct drm_panel *panel)
245 {
246 int ret;
247
248 if (!panel)
249 return -EINVAL;
250
251 ret = backlight_disable(panel->backlight);
252 if (ret < 0)
253 DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",
254 ret);
255
256 if (panel->funcs && panel->funcs->disable)
257 return panel->funcs->disable(panel);
258
259 return 0;
260 }
261 EXPORT_SYMBOL(drm_panel_disable);
262
263 /**
264 * drm_panel_get_modes - probe the available display modes of a panel
265 * @panel: DRM panel
266 * @connector: DRM connector
267 *
268 * The modes probed from the panel are automatically added to the connector
269 * that the panel is attached to.
270 *
271 * Return: The number of modes available from the panel on success or a
272 * negative error code on failure.
273 */
drm_panel_get_modes(struct drm_panel * panel,struct drm_connector * connector)274 int drm_panel_get_modes(struct drm_panel *panel,
275 struct drm_connector *connector)
276 {
277 if (!panel)
278 return -EINVAL;
279
280 if (panel->funcs && panel->funcs->get_modes)
281 return panel->funcs->get_modes(panel, connector);
282
283 return -EOPNOTSUPP;
284 }
285 EXPORT_SYMBOL(drm_panel_get_modes);
286
287 #ifdef CONFIG_OF
288 /**
289 * of_drm_find_panel - look up a panel using a device tree node
290 * @np: device tree node of the panel
291 *
292 * Searches the set of registered panels for one that matches the given device
293 * tree node. If a matching panel is found, return a pointer to it.
294 *
295 * Return: A pointer to the panel registered for the specified device tree
296 * node or an ERR_PTR() if no panel matching the device tree node can be found.
297 *
298 * Possible error codes returned by this function:
299 *
300 * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
301 * should retry later
302 * - ENODEV: the device is not available (status != "okay" or "ok")
303 */
of_drm_find_panel(const struct device_node * np)304 struct drm_panel *of_drm_find_panel(const struct device_node *np)
305 {
306 struct drm_panel *panel;
307
308 if (!of_device_is_available(np))
309 return ERR_PTR(-ENODEV);
310
311 mutex_lock(&panel_lock);
312
313 list_for_each_entry(panel, &panel_list, list) {
314 if (panel->dev->of_node == np) {
315 mutex_unlock(&panel_lock);
316 return panel;
317 }
318 }
319
320 mutex_unlock(&panel_lock);
321 return ERR_PTR(-EPROBE_DEFER);
322 }
323 EXPORT_SYMBOL(of_drm_find_panel);
324 #endif
325
326 #if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
327 /**
328 * drm_panel_of_backlight - use backlight device node for backlight
329 * @panel: DRM panel
330 *
331 * Use this function to enable backlight handling if your panel
332 * uses device tree and has a backlight phandle.
333 *
334 * When the panel is enabled backlight will be enabled after a
335 * successful call to &drm_panel_funcs.enable()
336 *
337 * When the panel is disabled backlight will be disabled before the
338 * call to &drm_panel_funcs.disable().
339 *
340 * A typical implementation for a panel driver supporting device tree
341 * will call this function at probe time. Backlight will then be handled
342 * transparently without requiring any intervention from the driver.
343 * drm_panel_of_backlight() must be called after the call to drm_panel_init().
344 *
345 * Return: 0 on success or a negative error code on failure.
346 */
drm_panel_of_backlight(struct drm_panel * panel)347 int drm_panel_of_backlight(struct drm_panel *panel)
348 {
349 struct backlight_device *backlight;
350
351 if (!panel || !panel->dev)
352 return -EINVAL;
353
354 backlight = devm_of_find_backlight(panel->dev);
355
356 if (IS_ERR(backlight))
357 return PTR_ERR(backlight);
358
359 panel->backlight = backlight;
360 return 0;
361 }
362 EXPORT_SYMBOL(drm_panel_of_backlight);
363 #endif
364
365 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
366 MODULE_DESCRIPTION("DRM panel infrastructure");
367 MODULE_LICENSE("GPL and additional rights");
368