1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
|
/*
* hdmi_state_machine.h
*
* HDMI library support functions for Nvidia Tegra processors.
*
* Copyright (C) 2013 Google - http://www.google.com/
* Copyright (C) 2013-2014, NVIDIA CORPORATION. All rights reserved.
* Authors: John Grossman <johngro@google.com>
* Authors: Mike J. Chen <mjchen@google.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __TEGRA_HDMI_STATE_MACHINE_H
#define __TEGRA_HDMI_STATE_MACHINE_H
#include "hdmi.h"
enum {
/* The initial state for the state machine. When entering RESET, we
* shut down all output and then proceed to the CHECK_PLUG state after a
* short debounce delay.
*/
HDMI_STATE_RESET = 0,
/* After the debounce delay, check the status of the HPD line. If its
* low, then the cable is unplugged and we go directly to DONE_DISABLED.
* If it is high, then the cable is plugged and we proceed to CHECK_EDID
* in order to read the EDID and figure out the next step.
*/
HDMI_STATE_CHECK_PLUG_STATE,
/* CHECK_EDID is the state we stay in attempting to read the EDID
* information after we check the plug state and discover that we are
* plugged in. If we max out our retries and fail to read the EDID, we
* move to DONE_DISABLED. If we successfully read the EDID, we move on
* to DONE_ENABLE, set an initial video mode, then signal to the high
* level that we are ready for final mode selection.
*/
HDMI_STATE_CHECK_EDID,
/* DONE_DISABLED is the state we stay in after being reset and either
* discovering that no cable is plugged in or after we think a cable is
* plugged in but fail to read EDID.
*/
HDMI_STATE_DONE_DISABLED,
/* DONE_ENABLED is the state we say in after being reset and disovering
* a valid EDID at the other end of a plugged cable.
*/
HDMI_STATE_DONE_ENABLED,
/* Some sinks will drop HPD as soon as the TMDS signals start up. They
* will hold HPD low for about second and then re-assert it. If the
* source simply holds steady and does not disable the TMDS lines, the
* sink seems to accept the video mode after having gone out to lunch
* for a bit. This seems to be the behavior of various sources which
* work with panels like this, so it is the behavior we emulate here.
* If HPD drops while we are in DONE_ENABLED, set a timer for 1.5
* seconds and transition to WAIT_FOR_HPD_REASSERT. If HPD has not come
* back within this time limit, then go ahead and transition to RESET
* and shut the system down. If HPD does come back within this time
* limit, then check the EDID again. If it has not changed, then we
* assume that we are still hooked to the same panel and just go back to
* DONE_ENABLED. If the EDID fails to read or has changed, we
* transition to RESET and start the system over again.
*/
HDMI_STATE_DONE_WAIT_FOR_HPD_REASSERT,
/* RECHECK_EDID is the state we stay in while attempting to re-read the
* EDID following an HPD drop and re-assert which occurs while we are in
* the DONE_ENABLED state. see HDMI_STATE_DONE_WAIT_FOR_HPD_REASSERT
* for more details.
*/
HDMI_STATE_DONE_RECHECK_EDID,
/* Initial state at boot that checks if HDMI is already initialized
* by bootloader and not go to HDMI_STATE_RESET which would disable
* HDMI and cause blanking of the bootloader displayed image.
*/
HDMI_STATE_INIT_FROM_BOOTLOADER,
/* STATE_COUNT must be the final state in the enum.
* 1) Do not add states after STATE_COUNT.
* 2) Do not assign explicit values to the states.
* 3) Do not reorder states in the list without reordering the dispatch
* table in hdmi_state_machine.c
*/
HDMI_STATE_COUNT,
};
void hdmi_state_machine_init(struct tegra_dc_hdmi_data *hdmi);
void hdmi_state_machine_shutdown(void);
void hdmi_state_machine_set_pending_hpd(void);
int hdmi_state_machine_get_state(void);
#endif /* __TEGRA_HDMI_STATE_MACHINE_H */
|
