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