214 lines
6.6 KiB
C
214 lines
6.6 KiB
C
/*
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* hpd.h: hotplug detection declarations.
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*
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* Copyright (c) 2015-2018, NVIDIA CORPORATION, All rights reserved.
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* Author: Animesh Kishore <ankishore@nvidia.com>
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#ifndef __DRIVERS_VIDEO_TEGRA_DC_HPD_H__
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#define __DRIVERS_VIDEO_TEGRA_DC_HPD_H__
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#include "edid.h"
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struct tegra_hpd_ops {
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/* custom init state machine */
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void (*init)(void *drv_data);
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/* return if hpd asserted/de-asserted */
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bool (*get_hpd_state)(void *drv_data);
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/*
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* panel is disconnected here.
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* Disable display and notify others.
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* Userspace has not yet been notified.
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*/
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void (*disable)(void *drv_data);
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/* prepare to initiate edid read tx */
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bool (*edid_read_prepare)(void *drv_data);
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/* edid is available but no notification sent yet. */
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void (*edid_ready)(void *drv_data);
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/*
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* hpd dropped but came back again
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* in < HPD_DROP_TIMEOUT_MS.
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* Check for any edid change has been done.
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*/
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void (*edid_recheck)(void *drv_data);
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/* filter modes not supported by host */
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bool (*(*get_mode_filter)(void *drv_data))
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(const struct tegra_dc *dc, struct fb_videomode *mode);
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/* core func to read edid over host-sink connection */
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i2c_transfer_func_t (*edid_read)(void *drv_data);
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/*
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* edid is available. Notification sent.
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* Add more notification here.
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*/
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void (*edid_notify)(void *drv_data);
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};
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struct tegra_hpd_timer_data {
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/* How long HPD must be HIGH to be a legitimate PLUG event */
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u32 plug_stabilize_delay_us;
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/* How long HPD must be LOW to be a legitimate UNPLUG event */
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u32 unplug_stabilize_delay_us;
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/* How long to wait for HPD to be re-asserted once it goes LOW */
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u32 reassert_delay_us;
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/* How long to wait before attempting to read the EDID */
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u32 check_edid_delay_us;
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/*
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* If this flag is true, the HPD state machine will categorically reset
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* itself if HPD comes back up within the reassert_delay_us period.
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*
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* If this flag is false and HPD comes back up within the
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* reassert_delay_us period, the HPD state machine will only reset
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* itself if the EDID has changed.
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*/
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bool reset_on_reassert;
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/*
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* If this flag is true, the HPD state machine will categorically reset
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* itself if it receives a PLUG event while still enabled.
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*
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* If this flag is false, the state machine will ignore PLUG events that
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* occur in the above scenario.
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*/
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bool reset_on_plug_bounce;
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};
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struct tegra_hpd_data {
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struct delayed_work dwork;
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int shutdown;
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int state;
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bool req_suspend; /* not sticky */
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int pending_hpd_evt;
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void *drv_data;
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struct tegra_hpd_ops *ops;
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struct tegra_hpd_timer_data timer_data;
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struct fb_monspecs mon_spec;
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struct tegra_edid *edid;
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int edid_reads;
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struct tegra_edid_hdmi_eld eld;
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bool eld_retrieved;
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bool hpd_resuming;
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struct rt_mutex lock;
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#ifdef CONFIG_SWITCH
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struct switch_dev hpd_switch;
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#endif
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struct tegra_dc *dc;
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};
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enum {
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/*
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* The initial state for the state machine. When entering RESET, we
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* shut down all output and then proceed to the CHECK_PLUG state after a
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* short debounce delay.
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*/
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STATE_HPD_RESET = 0,
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/*
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* After the debounce delay, check the status of the HPD line. If its
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* low, then the cable is unplugged and we go directly to DONE_DISABLED.
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* If it is high, then the cable is plugged and we proceed to CHECK_EDID
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* in order to read the EDID and figure out the next step.
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*/
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STATE_PLUG,
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/*
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* CHECK_EDID is the state we stay in attempting to read the EDID
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* information after we check the plug state and discover that we are
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* plugged in. If we max out our retries and fail to read the EDID, we
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* move to DONE_DISABLED. If we successfully read the EDID, we move on
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* to DONE_ENABLE, set an initial video mode, then signal to the high
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* level that we are ready for final mode selection.
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*/
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STATE_CHECK_EDID,
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/*
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* DONE_DISABLED is the state we stay in after being reset and either
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* discovering that no cable is plugged in or after we think a cable is
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* plugged in but fail to read EDID.
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*/
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STATE_DONE_DISABLED,
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/*
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* DONE_ENABLED is the state we say in after being reset and disovering
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* a valid EDID at the other end of a plugged cable.
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*/
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STATE_DONE_ENABLED,
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/*
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* Some sinks will drop HPD as soon as the TMDS signals start up. They
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* will hold HPD low for about second and then re-assert it. If the
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* source simply holds steady and does not disable the TMDS lines, the
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* sink seems to accept the video mode after having gone out to lunch
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* for a bit. This seems to be the behavior of various sources which
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* work with panels like this, so it is the behavior we emulate here.
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* If HPD drops while we are in DONE_ENABLED, set a timer for 1.5
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* seconds and transition to WAIT_FOR_HPD_REASSERT. If HPD has not come
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* back within this time limit, then go ahead and transition to RESET
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* and shut the system down. If HPD does come back within this time
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* limit, then check the EDID again. If it has not changed, then we
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* assume that we are still hooked to the same panel and just go back to
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* DONE_ENABLED. If the EDID fails to read or has changed, we
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* transition to RESET and start the system over again.
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*/
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STATE_WAIT_FOR_HPD_REASSERT,
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/*
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* RECHECK_EDID is the state we stay in while attempting to re-read the
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* EDID following an HPD drop and re-assert which occurs while we are in
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* the DONE_ENABLED state. see HPD_STATE_DONE_WAIT_FOR_HPD_REASSERT
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* for more details.
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*/
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STATE_RECHECK_EDID,
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/*
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* Initial state at boot that checks if HPD is already initialized
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* by bootloader and not go to HPD_STATE_RESET which would disable
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* HPD and cause blanking of the bootloader displayed image.
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*/
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STATE_INIT_FROM_BOOTLOADER,
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/*
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* STATE_COUNT must be the final state in the enum.
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* 1) Do not add states after STATE_COUNT.
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* 2) Do not assign explicit values to the states.
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* 3) Do not reorder states in the list without reordering the dispatch
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* table in hpd.c
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*/
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HPD_STATE_COUNT,
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};
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void tegra_hpd_init(struct tegra_hpd_data *data, struct tegra_dc *dc,
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void *drv_data, struct tegra_hpd_ops *ops);
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void tegra_hpd_shutdown(struct tegra_hpd_data *data);
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void tegra_hpd_set_pending_evt(struct tegra_hpd_data *data);
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int tegra_hpd_get_state(struct tegra_hpd_data *data);
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void tegra_hpd_suspend(struct tegra_hpd_data *data);
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#endif
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