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/backlight.h>
25 #include <linux/err.h>
26 #include <linux/module.h>
27 #include <linux/of.h>
28
29 #include <drm/drm_crtc.h>
30 #include <drm/drm_panel.h>
31 #include <drm/drm_print.h>
32
33 static DEFINE_MUTEX(panel_lock);
34 static LIST_HEAD(panel_list);
35
36 /**
37 * DOC: drm panel
38 *
39 * The DRM panel helpers allow drivers to register panel objects with a
40 * central registry and provide functions to retrieve those panels in display
41 * drivers.
42 *
43 * For easy integration into drivers using the &drm_bridge infrastructure please
44 * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add().
45 */
46
47 /**
48 * drm_panel_init - initialize a panel
49 * @panel: DRM panel
50 * @dev: parent device of the panel
51 * @funcs: panel operations
52 * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to
53 * the panel interface (must NOT be DRM_MODE_CONNECTOR_Unknown)
54 *
55 * Initialize the panel structure for subsequent registration with
56 * drm_panel_add().
57 */
drm_panel_init(struct drm_panel * panel,struct device * dev,const struct drm_panel_funcs * funcs,int connector_type)58 void drm_panel_init(struct drm_panel *panel, struct device *dev,
59 const struct drm_panel_funcs *funcs, int connector_type)
60 {
61 if (connector_type == DRM_MODE_CONNECTOR_Unknown)
62 DRM_WARN("%s: %s: a valid connector type is required!\n", __func__, dev_name(dev));
63
64 INIT_LIST_HEAD(&panel->list);
65 INIT_LIST_HEAD(&panel->followers);
66 mutex_init(&panel->follower_lock);
67 panel->dev = dev;
68 panel->funcs = funcs;
69 panel->connector_type = connector_type;
70 }
71 EXPORT_SYMBOL(drm_panel_init);
72
73 /**
74 * drm_panel_add - add a panel to the global registry
75 * @panel: panel to add
76 *
77 * Add a panel to the global registry so that it can be looked up by display
78 * drivers.
79 */
drm_panel_add(struct drm_panel * panel)80 void drm_panel_add(struct drm_panel *panel)
81 {
82 mutex_lock(&panel_lock);
83 list_add_tail(&panel->list, &panel_list);
84 mutex_unlock(&panel_lock);
85 }
86 EXPORT_SYMBOL(drm_panel_add);
87
88 /**
89 * drm_panel_remove - remove a panel from the global registry
90 * @panel: DRM panel
91 *
92 * Removes a panel from the global registry.
93 */
drm_panel_remove(struct drm_panel * panel)94 void drm_panel_remove(struct drm_panel *panel)
95 {
96 mutex_lock(&panel_lock);
97 list_del_init(&panel->list);
98 mutex_unlock(&panel_lock);
99 }
100 EXPORT_SYMBOL(drm_panel_remove);
101
102 /**
103 * drm_panel_prepare - power on a panel
104 * @panel: DRM panel
105 *
106 * Calling this function will enable power and deassert any reset signals to
107 * the panel. After this has completed it is possible to communicate with any
108 * integrated circuitry via a command bus.
109 *
110 * Return: 0 on success or a negative error code on failure.
111 */
drm_panel_prepare(struct drm_panel * panel)112 int drm_panel_prepare(struct drm_panel *panel)
113 {
114 struct drm_panel_follower *follower;
115 int ret;
116
117 if (!panel)
118 return -EINVAL;
119
120 if (panel->prepared) {
121 dev_warn(panel->dev, "Skipping prepare of already prepared panel\n");
122 return 0;
123 }
124
125 mutex_lock(&panel->follower_lock);
126
127 if (panel->funcs && panel->funcs->prepare) {
128 ret = panel->funcs->prepare(panel);
129 if (ret < 0)
130 goto exit;
131 }
132 panel->prepared = true;
133
134 list_for_each_entry(follower, &panel->followers, list) {
135 ret = follower->funcs->panel_prepared(follower);
136 if (ret < 0)
137 dev_info(panel->dev, "%ps failed: %d\n",
138 follower->funcs->panel_prepared, ret);
139 }
140
141 ret = 0;
142 exit:
143 mutex_unlock(&panel->follower_lock);
144
145 return ret;
146 }
147 EXPORT_SYMBOL(drm_panel_prepare);
148
149 /**
150 * drm_panel_unprepare - power off a panel
151 * @panel: DRM panel
152 *
153 * Calling this function will completely power off a panel (assert the panel's
154 * reset, turn off power supplies, ...). After this function has completed, it
155 * is usually no longer possible to communicate with the panel until another
156 * call to drm_panel_prepare().
157 *
158 * Return: 0 on success or a negative error code on failure.
159 */
drm_panel_unprepare(struct drm_panel * panel)160 int drm_panel_unprepare(struct drm_panel *panel)
161 {
162 struct drm_panel_follower *follower;
163 int ret;
164
165 if (!panel)
166 return -EINVAL;
167
168 /*
169 * If you are seeing the warning below it likely means one of two things:
170 * - Your panel driver incorrectly calls drm_panel_unprepare() in its
171 * shutdown routine. You should delete this.
172 * - You are using panel-edp or panel-simple and your DRM modeset
173 * driver's shutdown() callback happened after the panel's shutdown().
174 * In this case the warning is harmless though ideally you should
175 * figure out how to reverse the order of the shutdown() callbacks.
176 */
177 if (!panel->prepared) {
178 dev_warn(panel->dev, "Skipping unprepare of already unprepared panel\n");
179 return 0;
180 }
181
182 mutex_lock(&panel->follower_lock);
183
184 list_for_each_entry(follower, &panel->followers, list) {
185 ret = follower->funcs->panel_unpreparing(follower);
186 if (ret < 0)
187 dev_info(panel->dev, "%ps failed: %d\n",
188 follower->funcs->panel_unpreparing, ret);
189 }
190
191 if (panel->funcs && panel->funcs->unprepare) {
192 ret = panel->funcs->unprepare(panel);
193 if (ret < 0)
194 goto exit;
195 }
196 panel->prepared = false;
197
198 ret = 0;
199 exit:
200 mutex_unlock(&panel->follower_lock);
201
202 return ret;
203 }
204 EXPORT_SYMBOL(drm_panel_unprepare);
205
206 /**
207 * drm_panel_enable - enable a panel
208 * @panel: DRM panel
209 *
210 * Calling this function will cause the panel display drivers to be turned on
211 * and the backlight to be enabled. Content will be visible on screen after
212 * this call completes.
213 *
214 * Return: 0 on success or a negative error code on failure.
215 */
drm_panel_enable(struct drm_panel * panel)216 int drm_panel_enable(struct drm_panel *panel)
217 {
218 int ret;
219
220 if (!panel)
221 return -EINVAL;
222
223 if (panel->enabled) {
224 dev_warn(panel->dev, "Skipping enable of already enabled panel\n");
225 return 0;
226 }
227
228 if (panel->funcs && panel->funcs->enable) {
229 ret = panel->funcs->enable(panel);
230 if (ret < 0)
231 return ret;
232 }
233 panel->enabled = true;
234
235 ret = backlight_enable(panel->backlight);
236 if (ret < 0)
237 DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",
238 ret);
239
240 return 0;
241 }
242 EXPORT_SYMBOL(drm_panel_enable);
243
244 /**
245 * drm_panel_disable - disable a panel
246 * @panel: DRM panel
247 *
248 * This will typically turn off the panel's backlight or disable the display
249 * drivers. For smart panels it should still be possible to communicate with
250 * the integrated circuitry via any command bus after this call.
251 *
252 * Return: 0 on success or a negative error code on failure.
253 */
drm_panel_disable(struct drm_panel * panel)254 int drm_panel_disable(struct drm_panel *panel)
255 {
256 int ret;
257
258 if (!panel)
259 return -EINVAL;
260
261 /*
262 * If you are seeing the warning below it likely means one of two things:
263 * - Your panel driver incorrectly calls drm_panel_disable() in its
264 * shutdown routine. You should delete this.
265 * - You are using panel-edp or panel-simple and your DRM modeset
266 * driver's shutdown() callback happened after the panel's shutdown().
267 * In this case the warning is harmless though ideally you should
268 * figure out how to reverse the order of the shutdown() callbacks.
269 */
270 if (!panel->enabled) {
271 dev_warn(panel->dev, "Skipping disable of already disabled panel\n");
272 return 0;
273 }
274
275 ret = backlight_disable(panel->backlight);
276 if (ret < 0)
277 DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",
278 ret);
279
280 if (panel->funcs && panel->funcs->disable) {
281 ret = panel->funcs->disable(panel);
282 if (ret < 0)
283 return ret;
284 }
285 panel->enabled = false;
286
287 return 0;
288 }
289 EXPORT_SYMBOL(drm_panel_disable);
290
291 /**
292 * drm_panel_get_modes - probe the available display modes of a panel
293 * @panel: DRM panel
294 * @connector: DRM connector
295 *
296 * The modes probed from the panel are automatically added to the connector
297 * that the panel is attached to.
298 *
299 * Return: The number of modes available from the panel on success, or 0 on
300 * failure (no modes).
301 */
drm_panel_get_modes(struct drm_panel * panel,struct drm_connector * connector)302 int drm_panel_get_modes(struct drm_panel *panel,
303 struct drm_connector *connector)
304 {
305 if (!panel)
306 return 0;
307
308 if (panel->funcs && panel->funcs->get_modes) {
309 int num;
310
311 num = panel->funcs->get_modes(panel, connector);
312 if (num > 0)
313 return num;
314 }
315
316 return 0;
317 }
318 EXPORT_SYMBOL(drm_panel_get_modes);
319
320 #ifdef CONFIG_OF
321 /**
322 * of_drm_find_panel - look up a panel using a device tree node
323 * @np: device tree node of the panel
324 *
325 * Searches the set of registered panels for one that matches the given device
326 * tree node. If a matching panel is found, return a pointer to it.
327 *
328 * Return: A pointer to the panel registered for the specified device tree
329 * node or an ERR_PTR() if no panel matching the device tree node can be found.
330 *
331 * Possible error codes returned by this function:
332 *
333 * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
334 * should retry later
335 * - ENODEV: the device is not available (status != "okay" or "ok")
336 */
of_drm_find_panel(const struct device_node * np)337 struct drm_panel *of_drm_find_panel(const struct device_node *np)
338 {
339 struct drm_panel *panel;
340
341 if (!of_device_is_available(np))
342 return ERR_PTR(-ENODEV);
343
344 mutex_lock(&panel_lock);
345
346 list_for_each_entry(panel, &panel_list, list) {
347 if (panel->dev->of_node == np) {
348 mutex_unlock(&panel_lock);
349 return panel;
350 }
351 }
352
353 mutex_unlock(&panel_lock);
354 return ERR_PTR(-EPROBE_DEFER);
355 }
356 EXPORT_SYMBOL(of_drm_find_panel);
357
358 /**
359 * of_drm_get_panel_orientation - look up the orientation of the panel through
360 * the "rotation" binding from a device tree node
361 * @np: device tree node of the panel
362 * @orientation: orientation enum to be filled in
363 *
364 * Looks up the rotation of a panel in the device tree. The orientation of the
365 * panel is expressed as a property name "rotation" in the device tree. The
366 * rotation in the device tree is counter clockwise.
367 *
368 * Return: 0 when a valid rotation value (0, 90, 180, or 270) is read or the
369 * rotation property doesn't exist. Return a negative error code on failure.
370 */
of_drm_get_panel_orientation(const struct device_node * np,enum drm_panel_orientation * orientation)371 int of_drm_get_panel_orientation(const struct device_node *np,
372 enum drm_panel_orientation *orientation)
373 {
374 int rotation, ret;
375
376 ret = of_property_read_u32(np, "rotation", &rotation);
377 if (ret == -EINVAL) {
378 /* Don't return an error if there's no rotation property. */
379 *orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
380 return 0;
381 }
382
383 if (ret < 0)
384 return ret;
385
386 if (rotation == 0)
387 *orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL;
388 else if (rotation == 90)
389 *orientation = DRM_MODE_PANEL_ORIENTATION_RIGHT_UP;
390 else if (rotation == 180)
391 *orientation = DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP;
392 else if (rotation == 270)
393 *orientation = DRM_MODE_PANEL_ORIENTATION_LEFT_UP;
394 else
395 return -EINVAL;
396
397 return 0;
398 }
399 EXPORT_SYMBOL(of_drm_get_panel_orientation);
400 #endif
401
402 /**
403 * drm_is_panel_follower() - Check if the device is a panel follower
404 * @dev: The 'struct device' to check
405 *
406 * This checks to see if a device needs to be power sequenced together with
407 * a panel using the panel follower API.
408 * At the moment panels can only be followed on device tree enabled systems.
409 * The "panel" property of the follower points to the panel to be followed.
410 *
411 * Return: true if we should be power sequenced with a panel; false otherwise.
412 */
drm_is_panel_follower(struct device * dev)413 bool drm_is_panel_follower(struct device *dev)
414 {
415 /*
416 * The "panel" property is actually a phandle, but for simplicity we
417 * don't bother trying to parse it here. We just need to know if the
418 * property is there.
419 */
420 return of_property_present(dev->of_node, "panel");
421 }
422 EXPORT_SYMBOL(drm_is_panel_follower);
423
424 /**
425 * drm_panel_add_follower() - Register something to follow panel state.
426 * @follower_dev: The 'struct device' for the follower.
427 * @follower: The panel follower descriptor for the follower.
428 *
429 * A panel follower is called right after preparing the panel and right before
430 * unpreparing the panel. It's primary intention is to power on an associated
431 * touchscreen, though it could be used for any similar devices. Multiple
432 * devices are allowed the follow the same panel.
433 *
434 * If a follower is added to a panel that's already been turned on, the
435 * follower's prepare callback is called right away.
436 *
437 * At the moment panels can only be followed on device tree enabled systems.
438 * The "panel" property of the follower points to the panel to be followed.
439 *
440 * Return: 0 or an error code. Note that -ENODEV means that we detected that
441 * follower_dev is not actually following a panel. The caller may
442 * choose to ignore this return value if following a panel is optional.
443 */
drm_panel_add_follower(struct device * follower_dev,struct drm_panel_follower * follower)444 int drm_panel_add_follower(struct device *follower_dev,
445 struct drm_panel_follower *follower)
446 {
447 struct device_node *panel_np;
448 struct drm_panel *panel;
449 int ret;
450
451 panel_np = of_parse_phandle(follower_dev->of_node, "panel", 0);
452 if (!panel_np)
453 return -ENODEV;
454
455 panel = of_drm_find_panel(panel_np);
456 of_node_put(panel_np);
457 if (IS_ERR(panel))
458 return PTR_ERR(panel);
459
460 get_device(panel->dev);
461 follower->panel = panel;
462
463 mutex_lock(&panel->follower_lock);
464
465 list_add_tail(&follower->list, &panel->followers);
466 if (panel->prepared) {
467 ret = follower->funcs->panel_prepared(follower);
468 if (ret < 0)
469 dev_info(panel->dev, "%ps failed: %d\n",
470 follower->funcs->panel_prepared, ret);
471 }
472
473 mutex_unlock(&panel->follower_lock);
474
475 return 0;
476 }
477 EXPORT_SYMBOL(drm_panel_add_follower);
478
479 /**
480 * drm_panel_remove_follower() - Reverse drm_panel_add_follower().
481 * @follower: The panel follower descriptor for the follower.
482 *
483 * Undo drm_panel_add_follower(). This includes calling the follower's
484 * unprepare function if we're removed from a panel that's currently prepared.
485 *
486 * Return: 0 or an error code.
487 */
drm_panel_remove_follower(struct drm_panel_follower * follower)488 void drm_panel_remove_follower(struct drm_panel_follower *follower)
489 {
490 struct drm_panel *panel = follower->panel;
491 int ret;
492
493 mutex_lock(&panel->follower_lock);
494
495 if (panel->prepared) {
496 ret = follower->funcs->panel_unpreparing(follower);
497 if (ret < 0)
498 dev_info(panel->dev, "%ps failed: %d\n",
499 follower->funcs->panel_unpreparing, ret);
500 }
501 list_del_init(&follower->list);
502
503 mutex_unlock(&panel->follower_lock);
504
505 put_device(panel->dev);
506 }
507 EXPORT_SYMBOL(drm_panel_remove_follower);
508
drm_panel_remove_follower_void(void * follower)509 static void drm_panel_remove_follower_void(void *follower)
510 {
511 drm_panel_remove_follower(follower);
512 }
513
514 /**
515 * devm_drm_panel_add_follower() - devm version of drm_panel_add_follower()
516 * @follower_dev: The 'struct device' for the follower.
517 * @follower: The panel follower descriptor for the follower.
518 *
519 * Handles calling drm_panel_remove_follower() using devm on the follower_dev.
520 *
521 * Return: 0 or an error code.
522 */
devm_drm_panel_add_follower(struct device * follower_dev,struct drm_panel_follower * follower)523 int devm_drm_panel_add_follower(struct device *follower_dev,
524 struct drm_panel_follower *follower)
525 {
526 int ret;
527
528 ret = drm_panel_add_follower(follower_dev, follower);
529 if (ret)
530 return ret;
531
532 return devm_add_action_or_reset(follower_dev,
533 drm_panel_remove_follower_void, follower);
534 }
535 EXPORT_SYMBOL(devm_drm_panel_add_follower);
536
537 #if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
538 /**
539 * drm_panel_of_backlight - use backlight device node for backlight
540 * @panel: DRM panel
541 *
542 * Use this function to enable backlight handling if your panel
543 * uses device tree and has a backlight phandle.
544 *
545 * When the panel is enabled backlight will be enabled after a
546 * successful call to &drm_panel_funcs.enable()
547 *
548 * When the panel is disabled backlight will be disabled before the
549 * call to &drm_panel_funcs.disable().
550 *
551 * A typical implementation for a panel driver supporting device tree
552 * will call this function at probe time. Backlight will then be handled
553 * transparently without requiring any intervention from the driver.
554 * drm_panel_of_backlight() must be called after the call to drm_panel_init().
555 *
556 * Return: 0 on success or a negative error code on failure.
557 */
drm_panel_of_backlight(struct drm_panel * panel)558 int drm_panel_of_backlight(struct drm_panel *panel)
559 {
560 struct backlight_device *backlight;
561
562 if (!panel || !panel->dev)
563 return -EINVAL;
564
565 backlight = devm_of_find_backlight(panel->dev);
566
567 if (IS_ERR(backlight))
568 return PTR_ERR(backlight);
569
570 panel->backlight = backlight;
571 return 0;
572 }
573 EXPORT_SYMBOL(drm_panel_of_backlight);
574 #endif
575
576 MODULE_AUTHOR("Thierry Reding <[email protected]>");
577 MODULE_DESCRIPTION("DRM panel infrastructure");
578 MODULE_LICENSE("GPL and additional rights");
579