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