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/errno.h>
28#include <linux/list.h>
29
30struct device_node;
31struct drm_connector;
32struct drm_device;
33struct drm_panel;
34struct display_timing;
35
36/**
37 * struct drm_panel_funcs - perform operations on a given panel
38 * @disable: disable panel (turn off back light, etc.)
39 * @unprepare: turn off panel
40 * @prepare: turn on panel and perform set up
41 * @enable: enable panel (turn on back light, etc.)
42 * @get_modes: add modes to the connector that the panel is attached to and
43 * return the number of modes added
44 * @get_timings: copy display timings into the provided array and return
45 * the number of display timings available
46 *
47 * The .prepare() function is typically called before the display controller
48 * starts to transmit video data. Panel drivers can use this to turn the panel
49 * on and wait for it to become ready. If additional configuration is required
50 * (via a control bus such as I2C, SPI or DSI for example) this is a good time
51 * to do that.
52 *
53 * After the display controller has started transmitting video data, it's safe
54 * to call the .enable() function. This will typically enable the backlight to
55 * make the image on screen visible. Some panels require a certain amount of
56 * time or frames before the image is displayed. This function is responsible
57 * for taking this into account before enabling the backlight to avoid visual
58 * glitches.
59 *
60 * Before stopping video transmission from the display controller it can be
61 * necessary to turn off the panel to avoid visual glitches. This is done in
62 * the .disable() function. Analogously to .enable() this typically involves
63 * turning off the backlight and waiting for some time to make sure no image
64 * is visible on the panel. It is then safe for the display controller to
65 * cease transmission of video data.
66 *
67 * To save power when no video data is transmitted, a driver can power down
68 * the panel. This is the job of the .unprepare() function.
69 */
70struct drm_panel_funcs {
71 int (*disable)(struct drm_panel *panel);
72 int (*unprepare)(struct drm_panel *panel);
73 int (*prepare)(struct drm_panel *panel);
74 int (*enable)(struct drm_panel *panel);
75 int (*get_modes)(struct drm_panel *panel);
76 int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
77 struct display_timing *timings);
78};
79
80/**
81 * struct drm_panel - DRM panel object
82 * @drm: DRM device owning the panel
83 * @connector: DRM connector that the panel is attached to
84 * @dev: parent device of the panel
85 * @link: link from panel device (supplier) to DRM device (consumer)
86 * @funcs: operations that can be performed on the panel
87 * @list: panel entry in registry
88 */
89struct drm_panel {
90 struct drm_device *drm;
91 struct drm_connector *connector;
92 struct device *dev;
93
94 const struct drm_panel_funcs *funcs;
95
96 struct list_head list;
97};
98
99/**
100 * drm_disable_unprepare - power off a panel
101 * @panel: DRM panel
102 *
103 * Calling this function will completely power off a panel (assert the panel's
104 * reset, turn off power supplies, ...). After this function has completed, it
105 * is usually no longer possible to communicate with the panel until another
106 * call to drm_panel_prepare().
107 *
108 * Return: 0 on success or a negative error code on failure.
109 */
110static inline int drm_panel_unprepare(struct drm_panel *panel)
111{
112 if (panel && panel->funcs && panel->funcs->unprepare)
113 return panel->funcs->unprepare(panel);
114
115 return panel ? -ENOSYS : -EINVAL;
116}
117
118/**
119 * drm_panel_disable - disable a panel
120 * @panel: DRM panel
121 *
122 * This will typically turn off the panel's backlight or disable the display
123 * drivers. For smart panels it should still be possible to communicate with
124 * the integrated circuitry via any command bus after this call.
125 *
126 * Return: 0 on success or a negative error code on failure.
127 */
128static inline int drm_panel_disable(struct drm_panel *panel)
129{
130 if (panel && panel->funcs && panel->funcs->disable)
131 return panel->funcs->disable(panel);
132
133 return panel ? -ENOSYS : -EINVAL;
134}
135
136/**
137 * drm_panel_prepare - power on a panel
138 * @panel: DRM panel
139 *
140 * Calling this function will enable power and deassert any reset signals to
141 * the panel. After this has completed it is possible to communicate with any
142 * integrated circuitry via a command bus.
143 *
144 * Return: 0 on success or a negative error code on failure.
145 */
146static inline int drm_panel_prepare(struct drm_panel *panel)
147{
148 if (panel && panel->funcs && panel->funcs->prepare)
149 return panel->funcs->prepare(panel);
150
151 return panel ? -ENOSYS : -EINVAL;
152}
153
154/**
155 * drm_panel_enable - enable a panel
156 * @panel: DRM panel
157 *
158 * Calling this function will cause the panel display drivers to be turned on
159 * and the backlight to be enabled. Content will be visible on screen after
160 * this call completes.
161 *
162 * Return: 0 on success or a negative error code on failure.
163 */
164static inline int drm_panel_enable(struct drm_panel *panel)
165{
166 if (panel && panel->funcs && panel->funcs->enable)
167 return panel->funcs->enable(panel);
168
169 return panel ? -ENOSYS : -EINVAL;
170}
171
172/**
173 * drm_panel_get_modes - probe the available display modes of a panel
174 * @panel: DRM panel
175 *
176 * The modes probed from the panel are automatically added to the connector
177 * that the panel is attached to.
178 *
179 * Return: The number of modes available from the panel on success or a
180 * negative error code on failure.
181 */
182static inline int drm_panel_get_modes(struct drm_panel *panel)
183{
184 if (panel && panel->funcs && panel->funcs->get_modes)
185 return panel->funcs->get_modes(panel);
186
187 return panel ? -ENOSYS : -EINVAL;
188}
189
190void drm_panel_init(struct drm_panel *panel);
191
192int drm_panel_add(struct drm_panel *panel);
193void drm_panel_remove(struct drm_panel *panel);
194
195int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector);
196int drm_panel_detach(struct drm_panel *panel);
197
198#if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
199struct drm_panel *of_drm_find_panel(const struct device_node *np);
200#else
201static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
202{
203 return ERR_PTR(-ENODEV);
204}
205#endif
206
207#endif
208