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/list.h>
 28
 29struct drm_connector;
 30struct drm_device;
 31struct drm_panel;
 32struct display_timing;
 33
 34/**
 35 * struct drm_panel_funcs - perform operations on a given panel
 36 * @disable: disable panel (turn off back light, etc.)
 37 * @unprepare: turn off panel
 38 * @prepare: turn on panel and perform set up
 39 * @enable: enable panel (turn on back light, etc.)
 40 * @get_modes: add modes to the connector that the panel is attached to and
 41 * return the number of modes added
 42 * @get_timings: copy display timings into the provided array and return
 43 * the number of display timings available
 44 *
 45 * The .prepare() function is typically called before the display controller
 46 * starts to transmit video data. Panel drivers can use this to turn the panel
 47 * on and wait for it to become ready. If additional configuration is required
 48 * (via a control bus such as I2C, SPI or DSI for example) this is a good time
 49 * to do that.
 50 *
 51 * After the display controller has started transmitting video data, it's safe
 52 * to call the .enable() function. This will typically enable the backlight to
 53 * make the image on screen visible. Some panels require a certain amount of
 54 * time or frames before the image is displayed. This function is responsible
 55 * for taking this into account before enabling the backlight to avoid visual
 56 * glitches.
 57 *
 58 * Before stopping video transmission from the display controller it can be
 59 * necessary to turn off the panel to avoid visual glitches. This is done in
 60 * the .disable() function. Analogously to .enable() this typically involves
 61 * turning off the backlight and waiting for some time to make sure no image
 62 * is visible on the panel. It is then safe for the display controller to
 63 * cease transmission of video data.
 64 *
 65 * To save power when no video data is transmitted, a driver can power down
 66 * the panel. This is the job of the .unprepare() function.
 67 */
 68struct drm_panel_funcs {
 69	int (*disable)(struct drm_panel *panel);
 70	int (*unprepare)(struct drm_panel *panel);
 71	int (*prepare)(struct drm_panel *panel);
 72	int (*enable)(struct drm_panel *panel);
 73	int (*get_modes)(struct drm_panel *panel);
 74	int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
 75			   struct display_timing *timings);
 76};
 77
 78/**
 79 * struct drm_panel - DRM panel object
 80 * @drm: DRM device owning the panel
 81 * @connector: DRM connector that the panel is attached to
 82 * @dev: parent device of the panel
 83 * @funcs: operations that can be performed on the panel
 84 * @list: panel entry in registry
 85 */
 86struct drm_panel {
 87	struct drm_device *drm;
 88	struct drm_connector *connector;
 89	struct device *dev;
 90
 91	const struct drm_panel_funcs *funcs;
 92
 93	struct list_head list;
 94};
 95
 96/**
 97 * drm_disable_unprepare - power off a panel
 98 * @panel: DRM panel
 99 *
100 * Calling this function will completely power off a panel (assert the panel's
101 * reset, turn off power supplies, ...). After this function has completed, it
102 * is usually no longer possible to communicate with the panel until another
103 * call to drm_panel_prepare().
104 *
105 * Return: 0 on success or a negative error code on failure.
106 */
107static inline int drm_panel_unprepare(struct drm_panel *panel)
108{
109	if (panel && panel->funcs && panel->funcs->unprepare)
110		return panel->funcs->unprepare(panel);
111
112	return panel ? -ENOSYS : -EINVAL;
113}
114
115/**
116 * drm_panel_disable - disable a panel
117 * @panel: DRM panel
118 *
119 * This will typically turn off the panel's backlight or disable the display
120 * drivers. For smart panels it should still be possible to communicate with
121 * the integrated circuitry via any command bus after this call.
122 *
123 * Return: 0 on success or a negative error code on failure.
124 */
125static inline int drm_panel_disable(struct drm_panel *panel)
126{
127	if (panel && panel->funcs && panel->funcs->disable)
128		return panel->funcs->disable(panel);
129
130	return panel ? -ENOSYS : -EINVAL;
131}
132
133/**
134 * drm_panel_prepare - power on a panel
135 * @panel: DRM panel
136 *
137 * Calling this function will enable power and deassert any reset signals to
138 * the panel. After this has completed it is possible to communicate with any
139 * integrated circuitry via a command bus.
140 *
141 * Return: 0 on success or a negative error code on failure.
142 */
143static inline int drm_panel_prepare(struct drm_panel *panel)
144{
145	if (panel && panel->funcs && panel->funcs->prepare)
146		return panel->funcs->prepare(panel);
147
148	return panel ? -ENOSYS : -EINVAL;
149}
150
151/**
152 * drm_panel_enable - enable a panel
153 * @panel: DRM panel
154 *
155 * Calling this function will cause the panel display drivers to be turned on
156 * and the backlight to be enabled. Content will be visible on screen after
157 * this call completes.
158 *
159 * Return: 0 on success or a negative error code on failure.
160 */
161static inline int drm_panel_enable(struct drm_panel *panel)
162{
163	if (panel && panel->funcs && panel->funcs->enable)
164		return panel->funcs->enable(panel);
165
166	return panel ? -ENOSYS : -EINVAL;
167}
168
169/**
170 * drm_panel_get_modes - probe the available display modes of a panel
171 * @panel: DRM panel
172 *
173 * The modes probed from the panel are automatically added to the connector
174 * that the panel is attached to.
175 *
176 * Return: The number of modes available from the panel on success or a
177 * negative error code on failure.
178 */
179static inline int drm_panel_get_modes(struct drm_panel *panel)
180{
181	if (panel && panel->funcs && panel->funcs->get_modes)
182		return panel->funcs->get_modes(panel);
183
184	return panel ? -ENOSYS : -EINVAL;
185}
186
187void drm_panel_init(struct drm_panel *panel);
188
189int drm_panel_add(struct drm_panel *panel);
190void drm_panel_remove(struct drm_panel *panel);
191
192int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector);
193int drm_panel_detach(struct drm_panel *panel);
194
195#ifdef CONFIG_OF
196struct drm_panel *of_drm_find_panel(struct device_node *np);
197#else
198static inline struct drm_panel *of_drm_find_panel(struct device_node *np)
199{
200	return NULL;
201}
202#endif
203
204#endif