Commit | Line | Data |
---|---|---|
aead40ea TR |
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 | ||
152dbdea | 24 | #include <linux/backlight.h> |
aead40ea TR |
25 | #include <linux/err.h> |
26 | #include <linux/module.h> | |
27 | ||
28 | #include <drm/drm_crtc.h> | |
29 | #include <drm/drm_panel.h> | |
152dbdea | 30 | #include <drm/drm_print.h> |
aead40ea TR |
31 | |
32 | static DEFINE_MUTEX(panel_lock); | |
33 | static LIST_HEAD(panel_list); | |
34 | ||
83127f67 TR |
35 | /** |
36 | * DOC: drm panel | |
37 | * | |
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 | |
40 | * drivers. | |
0aa5eb3a DV |
41 | * |
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(). | |
83127f67 TR |
44 | */ |
45 | ||
46 | /** | |
47 | * drm_panel_init - initialize a panel | |
48 | * @panel: DRM panel | |
6dbe0c4b LP |
49 | * @dev: parent device of the panel |
50 | * @funcs: panel operations | |
9a2654c0 LP |
51 | * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to |
52 | * the panel interface | |
83127f67 | 53 | * |
6dbe0c4b LP |
54 | * Initialize the panel structure for subsequent registration with |
55 | * drm_panel_add(). | |
83127f67 | 56 | */ |
6dbe0c4b | 57 | void drm_panel_init(struct drm_panel *panel, struct device *dev, |
9a2654c0 | 58 | const struct drm_panel_funcs *funcs, int connector_type) |
aead40ea TR |
59 | { |
60 | INIT_LIST_HEAD(&panel->list); | |
de087416 DA |
61 | INIT_LIST_HEAD(&panel->followers); |
62 | mutex_init(&panel->follower_lock); | |
6dbe0c4b LP |
63 | panel->dev = dev; |
64 | panel->funcs = funcs; | |
9a2654c0 | 65 | panel->connector_type = connector_type; |
aead40ea TR |
66 | } |
67 | EXPORT_SYMBOL(drm_panel_init); | |
68 | ||
83127f67 TR |
69 | /** |
70 | * drm_panel_add - add a panel to the global registry | |
71 | * @panel: panel to add | |
72 | * | |
73 | * Add a panel to the global registry so that it can be looked up by display | |
74 | * drivers. | |
83127f67 | 75 | */ |
c3ee8c65 | 76 | void drm_panel_add(struct drm_panel *panel) |
aead40ea TR |
77 | { |
78 | mutex_lock(&panel_lock); | |
79 | list_add_tail(&panel->list, &panel_list); | |
80 | mutex_unlock(&panel_lock); | |
aead40ea TR |
81 | } |
82 | EXPORT_SYMBOL(drm_panel_add); | |
83 | ||
83127f67 TR |
84 | /** |
85 | * drm_panel_remove - remove a panel from the global registry | |
86 | * @panel: DRM panel | |
87 | * | |
88 | * Removes a panel from the global registry. | |
89 | */ | |
aead40ea TR |
90 | void drm_panel_remove(struct drm_panel *panel) |
91 | { | |
92 | mutex_lock(&panel_lock); | |
93 | list_del_init(&panel->list); | |
94 | mutex_unlock(&panel_lock); | |
95 | } | |
96 | EXPORT_SYMBOL(drm_panel_remove); | |
97 | ||
7a833d30 SR |
98 | /** |
99 | * drm_panel_prepare - power on a panel | |
100 | * @panel: DRM panel | |
101 | * | |
102 | * Calling this function will enable power and deassert any reset signals to | |
103 | * the panel. After this has completed it is possible to communicate with any | |
104 | * integrated circuitry via a command bus. | |
105 | * | |
106 | * Return: 0 on success or a negative error code on failure. | |
107 | */ | |
108 | int drm_panel_prepare(struct drm_panel *panel) | |
109 | { | |
de087416 | 110 | struct drm_panel_follower *follower; |
d2aacaf0 DA |
111 | int ret; |
112 | ||
5dce87a9 SR |
113 | if (!panel) |
114 | return -EINVAL; | |
115 | ||
d2aacaf0 DA |
116 | if (panel->prepared) { |
117 | dev_warn(panel->dev, "Skipping prepare of already prepared panel\n"); | |
118 | return 0; | |
119 | } | |
120 | ||
de087416 DA |
121 | mutex_lock(&panel->follower_lock); |
122 | ||
d2aacaf0 DA |
123 | if (panel->funcs && panel->funcs->prepare) { |
124 | ret = panel->funcs->prepare(panel); | |
125 | if (ret < 0) | |
de087416 | 126 | goto exit; |
d2aacaf0 DA |
127 | } |
128 | panel->prepared = true; | |
7a833d30 | 129 | |
de087416 DA |
130 | list_for_each_entry(follower, &panel->followers, list) { |
131 | ret = follower->funcs->panel_prepared(follower); | |
132 | if (ret < 0) | |
133 | dev_info(panel->dev, "%ps failed: %d\n", | |
134 | follower->funcs->panel_prepared, ret); | |
135 | } | |
136 | ||
137 | ret = 0; | |
138 | exit: | |
139 | mutex_unlock(&panel->follower_lock); | |
140 | ||
141 | return ret; | |
7a833d30 SR |
142 | } |
143 | EXPORT_SYMBOL(drm_panel_prepare); | |
144 | ||
145 | /** | |
146 | * drm_panel_unprepare - power off a panel | |
147 | * @panel: DRM panel | |
148 | * | |
149 | * Calling this function will completely power off a panel (assert the panel's | |
150 | * reset, turn off power supplies, ...). After this function has completed, it | |
151 | * is usually no longer possible to communicate with the panel until another | |
152 | * call to drm_panel_prepare(). | |
153 | * | |
154 | * Return: 0 on success or a negative error code on failure. | |
155 | */ | |
156 | int drm_panel_unprepare(struct drm_panel *panel) | |
157 | { | |
de087416 | 158 | struct drm_panel_follower *follower; |
d2aacaf0 DA |
159 | int ret; |
160 | ||
5dce87a9 SR |
161 | if (!panel) |
162 | return -EINVAL; | |
163 | ||
f00bfaca DA |
164 | /* |
165 | * If you are seeing the warning below it likely means one of two things: | |
166 | * - Your panel driver incorrectly calls drm_panel_unprepare() in its | |
167 | * shutdown routine. You should delete this. | |
168 | * - You are using panel-edp or panel-simple and your DRM modeset | |
169 | * driver's shutdown() callback happened after the panel's shutdown(). | |
170 | * In this case the warning is harmless though ideally you should | |
171 | * figure out how to reverse the order of the shutdown() callbacks. | |
172 | */ | |
d2aacaf0 DA |
173 | if (!panel->prepared) { |
174 | dev_warn(panel->dev, "Skipping unprepare of already unprepared panel\n"); | |
175 | return 0; | |
176 | } | |
177 | ||
de087416 DA |
178 | mutex_lock(&panel->follower_lock); |
179 | ||
180 | list_for_each_entry(follower, &panel->followers, list) { | |
181 | ret = follower->funcs->panel_unpreparing(follower); | |
182 | if (ret < 0) | |
183 | dev_info(panel->dev, "%ps failed: %d\n", | |
184 | follower->funcs->panel_unpreparing, ret); | |
185 | } | |
186 | ||
d2aacaf0 DA |
187 | if (panel->funcs && panel->funcs->unprepare) { |
188 | ret = panel->funcs->unprepare(panel); | |
189 | if (ret < 0) | |
de087416 | 190 | goto exit; |
d2aacaf0 DA |
191 | } |
192 | panel->prepared = false; | |
7a833d30 | 193 | |
de087416 DA |
194 | ret = 0; |
195 | exit: | |
196 | mutex_unlock(&panel->follower_lock); | |
197 | ||
198 | return ret; | |
7a833d30 SR |
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 | */ | |
212 | int drm_panel_enable(struct drm_panel *panel) | |
213 | { | |
152dbdea SR |
214 | int ret; |
215 | ||
5dce87a9 SR |
216 | if (!panel) |
217 | return -EINVAL; | |
218 | ||
d2aacaf0 DA |
219 | if (panel->enabled) { |
220 | dev_warn(panel->dev, "Skipping enable of already enabled panel\n"); | |
221 | return 0; | |
222 | } | |
223 | ||
152dbdea SR |
224 | if (panel->funcs && panel->funcs->enable) { |
225 | ret = panel->funcs->enable(panel); | |
226 | if (ret < 0) | |
227 | return ret; | |
228 | } | |
d2aacaf0 | 229 | panel->enabled = true; |
152dbdea SR |
230 | |
231 | ret = backlight_enable(panel->backlight); | |
232 | if (ret < 0) | |
233 | DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n", | |
234 | ret); | |
7a833d30 | 235 | |
5dce87a9 | 236 | return 0; |
7a833d30 SR |
237 | } |
238 | EXPORT_SYMBOL(drm_panel_enable); | |
239 | ||
240 | /** | |
241 | * drm_panel_disable - disable a panel | |
242 | * @panel: DRM panel | |
243 | * | |
244 | * This will typically turn off the panel's backlight or disable the display | |
245 | * drivers. For smart panels it should still be possible to communicate with | |
246 | * the integrated circuitry via any command bus after this call. | |
247 | * | |
248 | * Return: 0 on success or a negative error code on failure. | |
249 | */ | |
250 | int drm_panel_disable(struct drm_panel *panel) | |
251 | { | |
152dbdea SR |
252 | int ret; |
253 | ||
5dce87a9 SR |
254 | if (!panel) |
255 | return -EINVAL; | |
256 | ||
f00bfaca DA |
257 | /* |
258 | * If you are seeing the warning below it likely means one of two things: | |
259 | * - Your panel driver incorrectly calls drm_panel_disable() in its | |
260 | * shutdown routine. You should delete this. | |
261 | * - You are using panel-edp or panel-simple and your DRM modeset | |
262 | * driver's shutdown() callback happened after the panel's shutdown(). | |
263 | * In this case the warning is harmless though ideally you should | |
264 | * figure out how to reverse the order of the shutdown() callbacks. | |
265 | */ | |
d2aacaf0 DA |
266 | if (!panel->enabled) { |
267 | dev_warn(panel->dev, "Skipping disable of already disabled panel\n"); | |
268 | return 0; | |
269 | } | |
270 | ||
152dbdea SR |
271 | ret = backlight_disable(panel->backlight); |
272 | if (ret < 0) | |
273 | DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n", | |
274 | ret); | |
275 | ||
d2aacaf0 DA |
276 | if (panel->funcs && panel->funcs->disable) { |
277 | ret = panel->funcs->disable(panel); | |
278 | if (ret < 0) | |
279 | return ret; | |
280 | } | |
281 | panel->enabled = false; | |
7a833d30 | 282 | |
5dce87a9 | 283 | return 0; |
7a833d30 SR |
284 | } |
285 | EXPORT_SYMBOL(drm_panel_disable); | |
286 | ||
287 | /** | |
288 | * drm_panel_get_modes - probe the available display modes of a panel | |
289 | * @panel: DRM panel | |
06c4a9c2 | 290 | * @connector: DRM connector |
7a833d30 SR |
291 | * |
292 | * The modes probed from the panel are automatically added to the connector | |
293 | * that the panel is attached to. | |
294 | * | |
fc4e9772 JN |
295 | * Return: The number of modes available from the panel on success, or 0 on |
296 | * failure (no modes). | |
7a833d30 | 297 | */ |
06c4a9c2 SR |
298 | int drm_panel_get_modes(struct drm_panel *panel, |
299 | struct drm_connector *connector) | |
7a833d30 | 300 | { |
5dce87a9 | 301 | if (!panel) |
fc4e9772 | 302 | return 0; |
5dce87a9 | 303 | |
fc4e9772 JN |
304 | if (panel->funcs && panel->funcs->get_modes) { |
305 | int num; | |
7a833d30 | 306 | |
fc4e9772 JN |
307 | num = panel->funcs->get_modes(panel, connector); |
308 | if (num > 0) | |
309 | return num; | |
310 | } | |
311 | ||
312 | return 0; | |
7a833d30 SR |
313 | } |
314 | EXPORT_SYMBOL(drm_panel_get_modes); | |
315 | ||
aead40ea | 316 | #ifdef CONFIG_OF |
83127f67 TR |
317 | /** |
318 | * of_drm_find_panel - look up a panel using a device tree node | |
319 | * @np: device tree node of the panel | |
320 | * | |
321 | * Searches the set of registered panels for one that matches the given device | |
322 | * tree node. If a matching panel is found, return a pointer to it. | |
323 | * | |
324 | * Return: A pointer to the panel registered for the specified device tree | |
5fa8e4a2 | 325 | * node or an ERR_PTR() if no panel matching the device tree node can be found. |
3eb3cd04 | 326 | * |
c59eb3cf | 327 | * Possible error codes returned by this function: |
3eb3cd04 | 328 | * |
c59eb3cf BB |
329 | * - EPROBE_DEFER: the panel device has not been probed yet, and the caller |
330 | * should retry later | |
331 | * - ENODEV: the device is not available (status != "okay" or "ok") | |
83127f67 | 332 | */ |
327bc443 | 333 | struct drm_panel *of_drm_find_panel(const struct device_node *np) |
aead40ea TR |
334 | { |
335 | struct drm_panel *panel; | |
336 | ||
c59eb3cf BB |
337 | if (!of_device_is_available(np)) |
338 | return ERR_PTR(-ENODEV); | |
339 | ||
aead40ea TR |
340 | mutex_lock(&panel_lock); |
341 | ||
342 | list_for_each_entry(panel, &panel_list, list) { | |
343 | if (panel->dev->of_node == np) { | |
344 | mutex_unlock(&panel_lock); | |
345 | return panel; | |
346 | } | |
347 | } | |
348 | ||
349 | mutex_unlock(&panel_lock); | |
5fa8e4a2 | 350 | return ERR_PTR(-EPROBE_DEFER); |
aead40ea TR |
351 | } |
352 | EXPORT_SYMBOL(of_drm_find_panel); | |
5f3e7503 DB |
353 | |
354 | /** | |
355 | * of_drm_get_panel_orientation - look up the orientation of the panel through | |
356 | * the "rotation" binding from a device tree node | |
357 | * @np: device tree node of the panel | |
358 | * @orientation: orientation enum to be filled in | |
359 | * | |
360 | * Looks up the rotation of a panel in the device tree. The orientation of the | |
361 | * panel is expressed as a property name "rotation" in the device tree. The | |
362 | * rotation in the device tree is counter clockwise. | |
363 | * | |
364 | * Return: 0 when a valid rotation value (0, 90, 180, or 270) is read or the | |
365 | * rotation property doesn't exist. Return a negative error code on failure. | |
366 | */ | |
367 | int of_drm_get_panel_orientation(const struct device_node *np, | |
368 | enum drm_panel_orientation *orientation) | |
369 | { | |
370 | int rotation, ret; | |
371 | ||
372 | ret = of_property_read_u32(np, "rotation", &rotation); | |
373 | if (ret == -EINVAL) { | |
374 | /* Don't return an error if there's no rotation property. */ | |
375 | *orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN; | |
376 | return 0; | |
377 | } | |
378 | ||
379 | if (ret < 0) | |
380 | return ret; | |
381 | ||
382 | if (rotation == 0) | |
383 | *orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL; | |
384 | else if (rotation == 90) | |
385 | *orientation = DRM_MODE_PANEL_ORIENTATION_RIGHT_UP; | |
386 | else if (rotation == 180) | |
387 | *orientation = DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP; | |
388 | else if (rotation == 270) | |
389 | *orientation = DRM_MODE_PANEL_ORIENTATION_LEFT_UP; | |
390 | else | |
391 | return -EINVAL; | |
392 | ||
393 | return 0; | |
394 | } | |
395 | EXPORT_SYMBOL(of_drm_get_panel_orientation); | |
aead40ea TR |
396 | #endif |
397 | ||
de087416 DA |
398 | /** |
399 | * drm_is_panel_follower() - Check if the device is a panel follower | |
400 | * @dev: The 'struct device' to check | |
401 | * | |
402 | * This checks to see if a device needs to be power sequenced together with | |
403 | * a panel using the panel follower API. | |
404 | * At the moment panels can only be followed on device tree enabled systems. | |
405 | * The "panel" property of the follower points to the panel to be followed. | |
406 | * | |
407 | * Return: true if we should be power sequenced with a panel; false otherwise. | |
408 | */ | |
409 | bool drm_is_panel_follower(struct device *dev) | |
410 | { | |
411 | /* | |
412 | * The "panel" property is actually a phandle, but for simplicity we | |
413 | * don't bother trying to parse it here. We just need to know if the | |
414 | * property is there. | |
415 | */ | |
416 | return of_property_read_bool(dev->of_node, "panel"); | |
417 | } | |
418 | EXPORT_SYMBOL(drm_is_panel_follower); | |
419 | ||
420 | /** | |
421 | * drm_panel_add_follower() - Register something to follow panel state. | |
422 | * @follower_dev: The 'struct device' for the follower. | |
423 | * @follower: The panel follower descriptor for the follower. | |
424 | * | |
425 | * A panel follower is called right after preparing the panel and right before | |
426 | * unpreparing the panel. It's primary intention is to power on an associated | |
427 | * touchscreen, though it could be used for any similar devices. Multiple | |
428 | * devices are allowed the follow the same panel. | |
429 | * | |
430 | * If a follower is added to a panel that's already been turned on, the | |
431 | * follower's prepare callback is called right away. | |
432 | * | |
433 | * At the moment panels can only be followed on device tree enabled systems. | |
434 | * The "panel" property of the follower points to the panel to be followed. | |
435 | * | |
436 | * Return: 0 or an error code. Note that -ENODEV means that we detected that | |
437 | * follower_dev is not actually following a panel. The caller may | |
438 | * choose to ignore this return value if following a panel is optional. | |
439 | */ | |
440 | int drm_panel_add_follower(struct device *follower_dev, | |
441 | struct drm_panel_follower *follower) | |
442 | { | |
443 | struct device_node *panel_np; | |
444 | struct drm_panel *panel; | |
445 | int ret; | |
446 | ||
447 | panel_np = of_parse_phandle(follower_dev->of_node, "panel", 0); | |
448 | if (!panel_np) | |
449 | return -ENODEV; | |
450 | ||
451 | panel = of_drm_find_panel(panel_np); | |
452 | of_node_put(panel_np); | |
453 | if (IS_ERR(panel)) | |
454 | return PTR_ERR(panel); | |
455 | ||
456 | get_device(panel->dev); | |
457 | follower->panel = panel; | |
458 | ||
459 | mutex_lock(&panel->follower_lock); | |
460 | ||
461 | list_add_tail(&follower->list, &panel->followers); | |
462 | if (panel->prepared) { | |
463 | ret = follower->funcs->panel_prepared(follower); | |
464 | if (ret < 0) | |
465 | dev_info(panel->dev, "%ps failed: %d\n", | |
466 | follower->funcs->panel_prepared, ret); | |
467 | } | |
468 | ||
469 | mutex_unlock(&panel->follower_lock); | |
470 | ||
471 | return 0; | |
472 | } | |
473 | EXPORT_SYMBOL(drm_panel_add_follower); | |
474 | ||
475 | /** | |
476 | * drm_panel_remove_follower() - Reverse drm_panel_add_follower(). | |
477 | * @follower: The panel follower descriptor for the follower. | |
478 | * | |
479 | * Undo drm_panel_add_follower(). This includes calling the follower's | |
480 | * unprepare function if we're removed from a panel that's currently prepared. | |
481 | * | |
482 | * Return: 0 or an error code. | |
483 | */ | |
484 | void drm_panel_remove_follower(struct drm_panel_follower *follower) | |
485 | { | |
486 | struct drm_panel *panel = follower->panel; | |
487 | int ret; | |
488 | ||
489 | mutex_lock(&panel->follower_lock); | |
490 | ||
491 | if (panel->prepared) { | |
492 | ret = follower->funcs->panel_unpreparing(follower); | |
493 | if (ret < 0) | |
494 | dev_info(panel->dev, "%ps failed: %d\n", | |
495 | follower->funcs->panel_unpreparing, ret); | |
496 | } | |
497 | list_del_init(&follower->list); | |
498 | ||
499 | mutex_unlock(&panel->follower_lock); | |
500 | ||
501 | put_device(panel->dev); | |
502 | } | |
503 | EXPORT_SYMBOL(drm_panel_remove_follower); | |
504 | ||
505 | static void drm_panel_remove_follower_void(void *follower) | |
506 | { | |
507 | drm_panel_remove_follower(follower); | |
508 | } | |
509 | ||
510 | /** | |
511 | * devm_drm_panel_add_follower() - devm version of drm_panel_add_follower() | |
512 | * @follower_dev: The 'struct device' for the follower. | |
513 | * @follower: The panel follower descriptor for the follower. | |
514 | * | |
515 | * Handles calling drm_panel_remove_follower() using devm on the follower_dev. | |
516 | * | |
517 | * Return: 0 or an error code. | |
518 | */ | |
519 | int devm_drm_panel_add_follower(struct device *follower_dev, | |
520 | struct drm_panel_follower *follower) | |
521 | { | |
522 | int ret; | |
523 | ||
524 | ret = drm_panel_add_follower(follower_dev, follower); | |
525 | if (ret) | |
526 | return ret; | |
527 | ||
528 | return devm_add_action_or_reset(follower_dev, | |
529 | drm_panel_remove_follower_void, follower); | |
530 | } | |
531 | EXPORT_SYMBOL(devm_drm_panel_add_follower); | |
532 | ||
4a34a9dc | 533 | #if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE) |
152dbdea SR |
534 | /** |
535 | * drm_panel_of_backlight - use backlight device node for backlight | |
536 | * @panel: DRM panel | |
537 | * | |
538 | * Use this function to enable backlight handling if your panel | |
539 | * uses device tree and has a backlight phandle. | |
540 | * | |
541 | * When the panel is enabled backlight will be enabled after a | |
542 | * successful call to &drm_panel_funcs.enable() | |
543 | * | |
544 | * When the panel is disabled backlight will be disabled before the | |
545 | * call to &drm_panel_funcs.disable(). | |
546 | * | |
547 | * A typical implementation for a panel driver supporting device tree | |
548 | * will call this function at probe time. Backlight will then be handled | |
549 | * transparently without requiring any intervention from the driver. | |
550 | * drm_panel_of_backlight() must be called after the call to drm_panel_init(). | |
551 | * | |
552 | * Return: 0 on success or a negative error code on failure. | |
553 | */ | |
554 | int drm_panel_of_backlight(struct drm_panel *panel) | |
555 | { | |
556 | struct backlight_device *backlight; | |
557 | ||
558 | if (!panel || !panel->dev) | |
559 | return -EINVAL; | |
560 | ||
561 | backlight = devm_of_find_backlight(panel->dev); | |
562 | ||
563 | if (IS_ERR(backlight)) | |
564 | return PTR_ERR(backlight); | |
565 | ||
566 | panel->backlight = backlight; | |
567 | return 0; | |
568 | } | |
569 | EXPORT_SYMBOL(drm_panel_of_backlight); | |
570 | #endif | |
571 | ||
aead40ea TR |
572 | MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>"); |
573 | MODULE_DESCRIPTION("DRM panel infrastructure"); | |
574 | MODULE_LICENSE("GPL and additional rights"); |