drm_panel.h

  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#ifndef __DRM_PANEL_H__
 25#define __DRM_PANEL_H__
 26
 27#include <linux/err.h>
 28#include <linux/errno.h>
 29#include <linux/list.h>
 30#include <linux/mutex.h>
 31#include <linux/kref.h>
 32
 33struct backlight_device;
 34struct dentry;
 35struct device_node;
 36struct drm_connector;
 37struct drm_panel_follower;
 38struct drm_panel;
 39struct display_timing;
 40
 41enum drm_panel_orientation;
 42
 43/**
 44 * struct drm_panel_funcs - perform operations on a given panel
 45 *
 46 * The .prepare() function is typically called before the display controller
 47 * starts to transmit video data. Panel drivers can use this to turn the panel
 48 * on and wait for it to become ready. If additional configuration is required
 49 * (via a control bus such as I2C, SPI or DSI for example) this is a good time
 50 * to do that.
 51 *
 52 * After the display controller has started transmitting video data, it's safe
 53 * to call the .enable() function. This will typically enable the backlight to
 54 * make the image on screen visible. Some panels require a certain amount of
 55 * time or frames before the image is displayed. This function is responsible
 56 * for taking this into account before enabling the backlight to avoid visual
 57 * glitches.
 58 *
 59 * Before stopping video transmission from the display controller it can be
 60 * necessary to turn off the panel to avoid visual glitches. This is done in
 61 * the .disable() function. Analogously to .enable() this typically involves
 62 * turning off the backlight and waiting for some time to make sure no image
 63 * is visible on the panel. It is then safe for the display controller to
 64 * cease transmission of video data.
 65 *
 66 * To save power when no video data is transmitted, a driver can power down
 67 * the panel. This is the job of the .unprepare() function.
 68 *
 69 * Backlight can be handled automatically if configured using
 70 * drm_panel_of_backlight() or drm_panel_dp_aux_backlight(). Then the driver
 71 * does not need to implement the functionality to enable/disable backlight.
 72 */
 73struct drm_panel_funcs {
 74	/**
 75	 * @prepare:
 76	 *
 77	 * Turn on panel and perform set up.
 78	 *
 79	 * This function is optional.
 80	 */
 81	int (*prepare)(struct drm_panel *panel);
 82
 83	/**
 84	 * @enable:
 85	 *
 86	 * Enable panel (turn on back light, etc.).
 87	 *
 88	 * This function is optional.
 89	 */
 90	int (*enable)(struct drm_panel *panel);
 91
 92	/**
 93	 * @disable:
 94	 *
 95	 * Disable panel (turn off back light, etc.).
 96	 *
 97	 * This function is optional.
 98	 */
 99	int (*disable)(struct drm_panel *panel);
100
101	/**
102	 * @unprepare:
103	 *
104	 * Turn off panel.
105	 *
106	 * This function is optional.
107	 */
108	int (*unprepare)(struct drm_panel *panel);
109
110	/**
111	 * @get_modes:
112	 *
113	 * Add modes to the connector that the panel is attached to
114	 * and returns the number of modes added.
115	 *
116	 * This function is mandatory.
117	 */
118	int (*get_modes)(struct drm_panel *panel,
119			 struct drm_connector *connector);
120
121	/**
122	 * @get_orientation:
123	 *
124	 * Return the panel orientation set by device tree or EDID.
125	 *
126	 * This function is optional.
127	 */
128	enum drm_panel_orientation (*get_orientation)(struct drm_panel *panel);
129
130	/**
131	 * @get_timings:
132	 *
133	 * Copy display timings into the provided array and return
134	 * the number of display timings available.
135	 *
136	 * This function is optional.
137	 */
138	int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
139			   struct display_timing *timings);
140
141	/**
142	 * @debugfs_init:
143	 *
144	 * Allows panels to create panels-specific debugfs files.
145	 */
146	void (*debugfs_init)(struct drm_panel *panel, struct dentry *root);
147};
148
149struct drm_panel_follower_funcs {
150	/**
151	 * @panel_prepared:
152	 *
153	 * Called after the panel has been powered on.
154	 */
155	int (*panel_prepared)(struct drm_panel_follower *follower);
156
157	/**
158	 * @panel_unpreparing:
159	 *
160	 * Called before the panel is powered off.
161	 */
162	int (*panel_unpreparing)(struct drm_panel_follower *follower);
163
164	/**
165	 * @panel_enabled:
166	 *
167	 * Called after the panel and the backlight have been enabled.
168	 */
169	int (*panel_enabled)(struct drm_panel_follower *follower);
170
171	/**
172	 * @panel_disabling:
173	 *
174	 * Called before the panel and the backlight are disabled.
175	 */
176	int (*panel_disabling)(struct drm_panel_follower *follower);
177};
178
179struct drm_panel_follower {
180	/**
181	 * @funcs:
182	 *
183	 * Dependent device callbacks; should be initted by the caller.
184	 */
185	const struct drm_panel_follower_funcs *funcs;
186
187	/**
188	 * @list
189	 *
190	 * Used for linking into panel's list; set by drm_panel_add_follower().
191	 */
192	struct list_head list;
193
194	/**
195	 * @panel
196	 *
197	 * The panel we're dependent on; set by drm_panel_add_follower().
198	 */
199	struct drm_panel *panel;
200};
201
202/**
203 * struct drm_panel - DRM panel object
204 */
205struct drm_panel {
206	/**
207	 * @dev:
208	 *
209	 * Parent device of the panel.
210	 */
211	struct device *dev;
212
213	/**
214	 * @backlight:
215	 *
216	 * Backlight device, used to turn on backlight after the call
217	 * to enable(), and to turn off backlight before the call to
218	 * disable().
219	 * backlight is set by drm_panel_of_backlight() or
220	 * drm_panel_dp_aux_backlight() and drivers shall not assign it.
221	 */
222	struct backlight_device *backlight;
223
224	/**
225	 * @funcs:
226	 *
227	 * Operations that can be performed on the panel.
228	 */
229	const struct drm_panel_funcs *funcs;
230
231	/**
232	 * @connector_type:
233	 *
234	 * Type of the panel as a DRM_MODE_CONNECTOR_* value. This is used to
235	 * initialise the drm_connector corresponding to the panel with the
236	 * correct connector type.
237	 */
238	int connector_type;
239
240	/**
241	 * @list:
242	 *
243	 * Panel entry in registry.
244	 */
245	struct list_head list;
246
247	/**
248	 * @followers:
249	 *
250	 * A list of struct drm_panel_follower dependent on this panel.
251	 */
252	struct list_head followers;
253
254	/**
255	 * @follower_lock:
256	 *
257	 * Lock for followers list.
258	 */
259	struct mutex follower_lock;
260
261	/**
262	 * @prepare_prev_first:
263	 *
264	 * The previous controller should be prepared first, before the prepare
265	 * for the panel is called. This is largely required for DSI panels
266	 * where the DSI host controller should be initialised to LP-11 before
267	 * the panel is powered up.
268	 */
269	bool prepare_prev_first;
270
271	/**
272	 * @prepared:
273	 *
274	 * If true then the panel has been prepared.
275	 */
276	bool prepared;
277
278	/**
279	 * @enabled:
280	 *
281	 * If true then the panel has been enabled.
282	 */
283	bool enabled;
284
285	/**
286	 * @container: Pointer to the private driver struct embedding this
287	 * @struct drm_panel.
288	 */
289	void *container;
290
291	/**
292	 * @refcount: reference count of users referencing this panel.
293	 */
294	struct kref refcount;
295};
296
297void *__devm_drm_panel_alloc(struct device *dev, size_t size, size_t offset,
298			     const struct drm_panel_funcs *funcs,
299			     int connector_type);
300
301/**
302 * devm_drm_panel_alloc - Allocate and initialize a refcounted panel.
303 *
304 * @dev: struct device of the panel device
305 * @type: the type of the struct which contains struct &drm_panel
306 * @member: the name of the &drm_panel within @type
307 * @funcs: callbacks for this panel
308 * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to
309 * the panel interface
310 *
311 * The reference count of the returned panel is initialized to 1. This
312 * reference will be automatically dropped via devm (by calling
313 * drm_panel_put()) when @dev is removed.
314 *
315 * Returns:
316 * Pointer to container structure embedding the panel, ERR_PTR on failure.
317 */
318#define devm_drm_panel_alloc(dev, type, member, funcs, connector_type) \
319	((type *)__devm_drm_panel_alloc(dev, sizeof(type), \
320					offsetof(type, member), funcs, \
321					connector_type))
322
323void drm_panel_init(struct drm_panel *panel, struct device *dev,
324		    const struct drm_panel_funcs *funcs,
325		    int connector_type);
326
327struct drm_panel *drm_panel_get(struct drm_panel *panel);
328void drm_panel_put(struct drm_panel *panel);
329
330void drm_panel_add(struct drm_panel *panel);
331void drm_panel_remove(struct drm_panel *panel);
332
333void drm_panel_prepare(struct drm_panel *panel);
334void drm_panel_unprepare(struct drm_panel *panel);
335
336void drm_panel_enable(struct drm_panel *panel);
337void drm_panel_disable(struct drm_panel *panel);
338
339int drm_panel_get_modes(struct drm_panel *panel, struct drm_connector *connector);
340
341#if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
342struct drm_panel *of_drm_find_panel(const struct device_node *np);
343int of_drm_get_panel_orientation(const struct device_node *np,
344				 enum drm_panel_orientation *orientation);
345#else
346static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
347{
348	return ERR_PTR(-ENODEV);
349}
350
351static inline int of_drm_get_panel_orientation(const struct device_node *np,
352					       enum drm_panel_orientation *orientation)
353{
354	return -ENODEV;
355}
356#endif
357
358#if defined(CONFIG_DRM_PANEL)
359bool drm_is_panel_follower(struct device *dev);
360int drm_panel_add_follower(struct device *follower_dev,
361			   struct drm_panel_follower *follower);
362void drm_panel_remove_follower(struct drm_panel_follower *follower);
363int devm_drm_panel_add_follower(struct device *follower_dev,
364				struct drm_panel_follower *follower);
365#else
366static inline bool drm_is_panel_follower(struct device *dev)
367{
368	return false;
369}
370
371static inline int drm_panel_add_follower(struct device *follower_dev,
372					 struct drm_panel_follower *follower)
373{
374	return -ENODEV;
375}
376
377static inline void drm_panel_remove_follower(struct drm_panel_follower *follower) { }
378static inline int devm_drm_panel_add_follower(struct device *follower_dev,
379					      struct drm_panel_follower *follower)
380{
381	return -ENODEV;
382}
383#endif
384
385#if IS_ENABLED(CONFIG_DRM_PANEL) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \
386	(IS_MODULE(CONFIG_DRM) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE)))
387int drm_panel_of_backlight(struct drm_panel *panel);
388#else
389static inline int drm_panel_of_backlight(struct drm_panel *panel)
390{
391	return 0;
392}
393#endif
394
395#endif