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
 31struct backlight_device;
 32struct dentry;
 33struct device_node;
 34struct drm_connector;
 35struct drm_device;
 36struct drm_panel;
 37struct display_timing;
 38
 39enum drm_panel_orientation;
 40
 41/**
 42 * struct drm_panel_funcs - perform operations on a given panel
 43 *
 44 * The .prepare() function is typically called before the display controller
 45 * starts to transmit video data. Panel drivers can use this to turn the panel
 46 * on and wait for it to become ready. If additional configuration is required
 47 * (via a control bus such as I2C, SPI or DSI for example) this is a good time
 48 * to do that.
 49 *
 50 * After the display controller has started transmitting video data, it's safe
 51 * to call the .enable() function. This will typically enable the backlight to
 52 * make the image on screen visible. Some panels require a certain amount of
 53 * time or frames before the image is displayed. This function is responsible
 54 * for taking this into account before enabling the backlight to avoid visual
 55 * glitches.
 56 *
 57 * Before stopping video transmission from the display controller it can be
 58 * necessary to turn off the panel to avoid visual glitches. This is done in
 59 * the .disable() function. Analogously to .enable() this typically involves
 60 * turning off the backlight and waiting for some time to make sure no image
 61 * is visible on the panel. It is then safe for the display controller to
 62 * cease transmission of video data.
 63 *
 64 * To save power when no video data is transmitted, a driver can power down
 65 * the panel. This is the job of the .unprepare() function.
 66 *
 67 * Backlight can be handled automatically if configured using
 68 * drm_panel_of_backlight() or drm_panel_dp_aux_backlight(). Then the driver
 69 * does not need to implement the functionality to enable/disable backlight.
 70 */
 71struct drm_panel_funcs {
 72	/**
 73	 * @prepare:
 74	 *
 75	 * Turn on panel and perform set up.
 76	 *
 77	 * This function is optional.
 78	 */
 79	int (*prepare)(struct drm_panel *panel);
 80
 81	/**
 82	 * @enable:
 83	 *
 84	 * Enable panel (turn on back light, etc.).
 85	 *
 86	 * This function is optional.
 87	 */
 88	int (*enable)(struct drm_panel *panel);
 89
 90	/**
 91	 * @disable:
 92	 *
 93	 * Disable panel (turn off back light, etc.).
 94	 *
 95	 * This function is optional.
 96	 */
 97	int (*disable)(struct drm_panel *panel);
 98
 99	/**
100	 * @unprepare:
101	 *
102	 * Turn off panel.
103	 *
104	 * This function is optional.
105	 */
106	int (*unprepare)(struct drm_panel *panel);
107
108	/**
109	 * @get_modes:
110	 *
111	 * Add modes to the connector that the panel is attached to
112	 * and returns the number of modes added.
113	 *
114	 * This function is mandatory.
115	 */
116	int (*get_modes)(struct drm_panel *panel,
117			 struct drm_connector *connector);
118
119	/**
120	 * @get_orientation:
121	 *
122	 * Return the panel orientation set by device tree or EDID.
123	 *
124	 * This function is optional.
125	 */
126	enum drm_panel_orientation (*get_orientation)(struct drm_panel *panel);
127
128	/**
129	 * @get_timings:
130	 *
131	 * Copy display timings into the provided array and return
132	 * the number of display timings available.
133	 *
134	 * This function is optional.
135	 */
136	int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
137			   struct display_timing *timings);
138
139	/**
140	 * @debugfs_init:
141	 *
142	 * Allows panels to create panels-specific debugfs files.
143	 */
144	void (*debugfs_init)(struct drm_panel *panel, struct dentry *root);
145};
146
147/**
148 * struct drm_panel - DRM panel object
149 */
150struct drm_panel {
151	/**
152	 * @dev:
153	 *
154	 * Parent device of the panel.
155	 */
156	struct device *dev;
157
158	/**
159	 * @backlight:
160	 *
161	 * Backlight device, used to turn on backlight after the call
162	 * to enable(), and to turn off backlight before the call to
163	 * disable().
164	 * backlight is set by drm_panel_of_backlight() or
165	 * drm_panel_dp_aux_backlight() and drivers shall not assign it.
166	 */
167	struct backlight_device *backlight;
168
169	/**
170	 * @funcs:
171	 *
172	 * Operations that can be performed on the panel.
173	 */
174	const struct drm_panel_funcs *funcs;
175
176	/**
177	 * @connector_type:
178	 *
179	 * Type of the panel as a DRM_MODE_CONNECTOR_* value. This is used to
180	 * initialise the drm_connector corresponding to the panel with the
181	 * correct connector type.
182	 */
183	int connector_type;
184
185	/**
186	 * @list:
187	 *
188	 * Panel entry in registry.
189	 */
190	struct list_head list;
191};
192
193void drm_panel_init(struct drm_panel *panel, struct device *dev,
194		    const struct drm_panel_funcs *funcs,
195		    int connector_type);
196
197void drm_panel_add(struct drm_panel *panel);
198void drm_panel_remove(struct drm_panel *panel);
199
200int drm_panel_prepare(struct drm_panel *panel);
201int drm_panel_unprepare(struct drm_panel *panel);
202
203int drm_panel_enable(struct drm_panel *panel);
204int drm_panel_disable(struct drm_panel *panel);
205
206int drm_panel_get_modes(struct drm_panel *panel, struct drm_connector *connector);
207
208#if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
209struct drm_panel *of_drm_find_panel(const struct device_node *np);
210int of_drm_get_panel_orientation(const struct device_node *np,
211				 enum drm_panel_orientation *orientation);
212#else
213static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
214{
215	return ERR_PTR(-ENODEV);
216}
217
218static inline int of_drm_get_panel_orientation(const struct device_node *np,
219					       enum drm_panel_orientation *orientation)
220{
221	return -ENODEV;
222}
223#endif
224
225#if IS_ENABLED(CONFIG_DRM_PANEL) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \
226	(IS_MODULE(CONFIG_DRM) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE)))
227int drm_panel_of_backlight(struct drm_panel *panel);
228#else
229static inline int drm_panel_of_backlight(struct drm_panel *panel)
230{
231	return 0;
232}
233#endif
234
235#endif