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![José Roberto de Souza](/assets/img/avatar_default.png)
drm_dp_cec_register_connector() is called when registering each DP connector in DRM, while sounds a good idea register CEC adapters as earlier as possible, it causes some driver initialization delay trying to do DPCD transactions in disconnected connectors. This change will cause no regressions as drm_dp_cec_set_edid() will still be called in further detection of connected connectors with a valid edid parameter. This change reduced the module load of i915 by average 0.5sec in a machine with just one DP port disconnected while reducing more than 3sec in a machine with 4 DP ports disconnected. Cc: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: José Roberto de Souza <jose.souza@intel.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20181011004439.4482-1-jose.souza@intel.com
442 lines
13 KiB
C
442 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* DisplayPort CEC-Tunneling-over-AUX support
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*
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* Copyright 2018 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <drm/drm_dp_helper.h>
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#include <media/cec.h>
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/*
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* Unfortunately it turns out that we have a chicken-and-egg situation
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* here. Quite a few active (mini-)DP-to-HDMI or USB-C-to-HDMI adapters
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* have a converter chip that supports CEC-Tunneling-over-AUX (usually the
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* Parade PS176), but they do not wire up the CEC pin, thus making CEC
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* useless. Note that MegaChips 2900-based adapters appear to have good
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* support for CEC tunneling. Those adapters that I have tested using
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* this chipset all have the CEC line connected.
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*
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* Sadly there is no way for this driver to know this. What happens is
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* that a /dev/cecX device is created that is isolated and unable to see
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* any of the other CEC devices. Quite literally the CEC wire is cut
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* (or in this case, never connected in the first place).
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*
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* The reason so few adapters support this is that this tunneling protocol
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* was never supported by any OS. So there was no easy way of testing it,
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* and no incentive to correctly wire up the CEC pin.
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*
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* Hopefully by creating this driver it will be easier for vendors to
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* finally fix their adapters and test the CEC functionality.
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*
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* I keep a list of known working adapters here:
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*
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* https://hverkuil.home.xs4all.nl/cec-status.txt
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*
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* Please mail me (hverkuil@xs4all.nl) if you find an adapter that works
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* and is not yet listed there.
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*
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* Note that the current implementation does not support CEC over an MST hub.
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* As far as I can see there is no mechanism defined in the DisplayPort
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* standard to transport CEC interrupts over an MST device. It might be
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* possible to do this through polling, but I have not been able to get that
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* to work.
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*/
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/**
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* DOC: dp cec helpers
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*
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* These functions take care of supporting the CEC-Tunneling-over-AUX
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* feature of DisplayPort-to-HDMI adapters.
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*/
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/*
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* When the EDID is unset because the HPD went low, then the CEC DPCD registers
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* typically can no longer be read (true for a DP-to-HDMI adapter since it is
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* powered by the HPD). However, some displays toggle the HPD off and on for a
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* short period for one reason or another, and that would cause the CEC adapter
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* to be removed and added again, even though nothing else changed.
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*
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* This module parameter sets a delay in seconds before the CEC adapter is
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* actually unregistered. Only if the HPD does not return within that time will
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* the CEC adapter be unregistered.
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*
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* If it is set to a value >= NEVER_UNREG_DELAY, then the CEC adapter will never
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* be unregistered for as long as the connector remains registered.
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*
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* If it is set to 0, then the CEC adapter will be unregistered immediately as
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* soon as the HPD disappears.
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*
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* The default is one second to prevent short HPD glitches from unregistering
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* the CEC adapter.
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*
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* Note that for integrated HDMI branch devices that support CEC the DPCD
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* registers remain available even if the HPD goes low since it is not powered
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* by the HPD. In that case the CEC adapter will never be unregistered during
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* the life time of the connector. At least, this is the theory since I do not
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* have hardware with an integrated HDMI branch device that supports CEC.
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*/
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#define NEVER_UNREG_DELAY 1000
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static unsigned int drm_dp_cec_unregister_delay = 1;
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module_param(drm_dp_cec_unregister_delay, uint, 0600);
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MODULE_PARM_DESC(drm_dp_cec_unregister_delay,
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"CEC unregister delay in seconds, 0: no delay, >= 1000: never unregister");
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static int drm_dp_cec_adap_enable(struct cec_adapter *adap, bool enable)
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{
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struct drm_dp_aux *aux = cec_get_drvdata(adap);
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u32 val = enable ? DP_CEC_TUNNELING_ENABLE : 0;
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ssize_t err = 0;
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err = drm_dp_dpcd_writeb(aux, DP_CEC_TUNNELING_CONTROL, val);
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return (enable && err < 0) ? err : 0;
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}
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static int drm_dp_cec_adap_log_addr(struct cec_adapter *adap, u8 addr)
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{
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struct drm_dp_aux *aux = cec_get_drvdata(adap);
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/* Bit 15 (logical address 15) should always be set */
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u16 la_mask = 1 << CEC_LOG_ADDR_BROADCAST;
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u8 mask[2];
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ssize_t err;
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if (addr != CEC_LOG_ADDR_INVALID)
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la_mask |= adap->log_addrs.log_addr_mask | (1 << addr);
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mask[0] = la_mask & 0xff;
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mask[1] = la_mask >> 8;
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err = drm_dp_dpcd_write(aux, DP_CEC_LOGICAL_ADDRESS_MASK, mask, 2);
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return (addr != CEC_LOG_ADDR_INVALID && err < 0) ? err : 0;
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}
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static int drm_dp_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
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u32 signal_free_time, struct cec_msg *msg)
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{
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struct drm_dp_aux *aux = cec_get_drvdata(adap);
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unsigned int retries = min(5, attempts - 1);
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ssize_t err;
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err = drm_dp_dpcd_write(aux, DP_CEC_TX_MESSAGE_BUFFER,
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msg->msg, msg->len);
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if (err < 0)
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return err;
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err = drm_dp_dpcd_writeb(aux, DP_CEC_TX_MESSAGE_INFO,
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(msg->len - 1) | (retries << 4) |
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DP_CEC_TX_MESSAGE_SEND);
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return err < 0 ? err : 0;
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}
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static int drm_dp_cec_adap_monitor_all_enable(struct cec_adapter *adap,
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bool enable)
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{
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struct drm_dp_aux *aux = cec_get_drvdata(adap);
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ssize_t err;
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u8 val;
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if (!(adap->capabilities & CEC_CAP_MONITOR_ALL))
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return 0;
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err = drm_dp_dpcd_readb(aux, DP_CEC_TUNNELING_CONTROL, &val);
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if (err >= 0) {
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if (enable)
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val |= DP_CEC_SNOOPING_ENABLE;
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else
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val &= ~DP_CEC_SNOOPING_ENABLE;
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err = drm_dp_dpcd_writeb(aux, DP_CEC_TUNNELING_CONTROL, val);
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}
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return (enable && err < 0) ? err : 0;
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}
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static void drm_dp_cec_adap_status(struct cec_adapter *adap,
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struct seq_file *file)
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{
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struct drm_dp_aux *aux = cec_get_drvdata(adap);
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struct drm_dp_desc desc;
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struct drm_dp_dpcd_ident *id = &desc.ident;
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if (drm_dp_read_desc(aux, &desc, true))
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return;
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seq_printf(file, "OUI: %*phD\n",
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(int)sizeof(id->oui), id->oui);
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seq_printf(file, "ID: %*pE\n",
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(int)strnlen(id->device_id, sizeof(id->device_id)),
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id->device_id);
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seq_printf(file, "HW Rev: %d.%d\n", id->hw_rev >> 4, id->hw_rev & 0xf);
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/*
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* Show this both in decimal and hex: at least one vendor
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* always reports this in hex.
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*/
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seq_printf(file, "FW/SW Rev: %d.%d (0x%02x.0x%02x)\n",
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id->sw_major_rev, id->sw_minor_rev,
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id->sw_major_rev, id->sw_minor_rev);
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}
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static const struct cec_adap_ops drm_dp_cec_adap_ops = {
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.adap_enable = drm_dp_cec_adap_enable,
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.adap_log_addr = drm_dp_cec_adap_log_addr,
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.adap_transmit = drm_dp_cec_adap_transmit,
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.adap_monitor_all_enable = drm_dp_cec_adap_monitor_all_enable,
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.adap_status = drm_dp_cec_adap_status,
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};
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static int drm_dp_cec_received(struct drm_dp_aux *aux)
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{
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struct cec_adapter *adap = aux->cec.adap;
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struct cec_msg msg;
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u8 rx_msg_info;
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ssize_t err;
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err = drm_dp_dpcd_readb(aux, DP_CEC_RX_MESSAGE_INFO, &rx_msg_info);
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if (err < 0)
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return err;
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if (!(rx_msg_info & DP_CEC_RX_MESSAGE_ENDED))
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return 0;
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msg.len = (rx_msg_info & DP_CEC_RX_MESSAGE_LEN_MASK) + 1;
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err = drm_dp_dpcd_read(aux, DP_CEC_RX_MESSAGE_BUFFER, msg.msg, msg.len);
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if (err < 0)
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return err;
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cec_received_msg(adap, &msg);
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return 0;
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}
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static void drm_dp_cec_handle_irq(struct drm_dp_aux *aux)
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{
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struct cec_adapter *adap = aux->cec.adap;
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u8 flags;
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if (drm_dp_dpcd_readb(aux, DP_CEC_TUNNELING_IRQ_FLAGS, &flags) < 0)
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return;
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if (flags & DP_CEC_RX_MESSAGE_INFO_VALID)
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drm_dp_cec_received(aux);
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if (flags & DP_CEC_TX_MESSAGE_SENT)
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cec_transmit_attempt_done(adap, CEC_TX_STATUS_OK);
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else if (flags & DP_CEC_TX_LINE_ERROR)
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cec_transmit_attempt_done(adap, CEC_TX_STATUS_ERROR |
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CEC_TX_STATUS_MAX_RETRIES);
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else if (flags &
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(DP_CEC_TX_ADDRESS_NACK_ERROR | DP_CEC_TX_DATA_NACK_ERROR))
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cec_transmit_attempt_done(adap, CEC_TX_STATUS_NACK |
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CEC_TX_STATUS_MAX_RETRIES);
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drm_dp_dpcd_writeb(aux, DP_CEC_TUNNELING_IRQ_FLAGS, flags);
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}
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/**
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* drm_dp_cec_irq() - handle CEC interrupt, if any
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* @aux: DisplayPort AUX channel
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*
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* Should be called when handling an IRQ_HPD request. If CEC-tunneling-over-AUX
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* is present, then it will check for a CEC_IRQ and handle it accordingly.
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*/
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void drm_dp_cec_irq(struct drm_dp_aux *aux)
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{
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u8 cec_irq;
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int ret;
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/* No transfer function was set, so not a DP connector */
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if (!aux->transfer)
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return;
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mutex_lock(&aux->cec.lock);
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if (!aux->cec.adap)
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goto unlock;
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ret = drm_dp_dpcd_readb(aux, DP_DEVICE_SERVICE_IRQ_VECTOR_ESI1,
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&cec_irq);
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if (ret < 0 || !(cec_irq & DP_CEC_IRQ))
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goto unlock;
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drm_dp_cec_handle_irq(aux);
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drm_dp_dpcd_writeb(aux, DP_DEVICE_SERVICE_IRQ_VECTOR_ESI1, DP_CEC_IRQ);
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unlock:
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mutex_unlock(&aux->cec.lock);
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}
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EXPORT_SYMBOL(drm_dp_cec_irq);
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static bool drm_dp_cec_cap(struct drm_dp_aux *aux, u8 *cec_cap)
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{
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u8 cap = 0;
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if (drm_dp_dpcd_readb(aux, DP_CEC_TUNNELING_CAPABILITY, &cap) != 1 ||
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!(cap & DP_CEC_TUNNELING_CAPABLE))
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return false;
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if (cec_cap)
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*cec_cap = cap;
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return true;
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}
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/*
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* Called if the HPD was low for more than drm_dp_cec_unregister_delay
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* seconds. This unregisters the CEC adapter.
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*/
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static void drm_dp_cec_unregister_work(struct work_struct *work)
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{
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struct drm_dp_aux *aux = container_of(work, struct drm_dp_aux,
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cec.unregister_work.work);
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mutex_lock(&aux->cec.lock);
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cec_unregister_adapter(aux->cec.adap);
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aux->cec.adap = NULL;
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mutex_unlock(&aux->cec.lock);
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}
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/*
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* A new EDID is set. If there is no CEC adapter, then create one. If
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* there was a CEC adapter, then check if the CEC adapter properties
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* were unchanged and just update the CEC physical address. Otherwise
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* unregister the old CEC adapter and create a new one.
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*/
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void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const struct edid *edid)
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{
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u32 cec_caps = CEC_CAP_DEFAULTS | CEC_CAP_NEEDS_HPD;
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unsigned int num_las = 1;
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u8 cap;
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/* No transfer function was set, so not a DP connector */
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if (!aux->transfer)
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return;
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#ifndef CONFIG_MEDIA_CEC_RC
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/*
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* CEC_CAP_RC is part of CEC_CAP_DEFAULTS, but it is stripped by
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* cec_allocate_adapter() if CONFIG_MEDIA_CEC_RC is undefined.
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*
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* Do this here as well to ensure the tests against cec_caps are
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* correct.
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*/
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cec_caps &= ~CEC_CAP_RC;
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#endif
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cancel_delayed_work_sync(&aux->cec.unregister_work);
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mutex_lock(&aux->cec.lock);
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if (!drm_dp_cec_cap(aux, &cap)) {
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/* CEC is not supported, unregister any existing adapter */
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cec_unregister_adapter(aux->cec.adap);
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aux->cec.adap = NULL;
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goto unlock;
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}
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if (cap & DP_CEC_SNOOPING_CAPABLE)
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cec_caps |= CEC_CAP_MONITOR_ALL;
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if (cap & DP_CEC_MULTIPLE_LA_CAPABLE)
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num_las = CEC_MAX_LOG_ADDRS;
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if (aux->cec.adap) {
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if (aux->cec.adap->capabilities == cec_caps &&
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aux->cec.adap->available_log_addrs == num_las) {
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/* Unchanged, so just set the phys addr */
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cec_s_phys_addr_from_edid(aux->cec.adap, edid);
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goto unlock;
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}
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/*
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* The capabilities changed, so unregister the old
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* adapter first.
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*/
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cec_unregister_adapter(aux->cec.adap);
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}
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/* Create a new adapter */
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aux->cec.adap = cec_allocate_adapter(&drm_dp_cec_adap_ops,
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aux, aux->cec.name, cec_caps,
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num_las);
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if (IS_ERR(aux->cec.adap)) {
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aux->cec.adap = NULL;
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goto unlock;
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}
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if (cec_register_adapter(aux->cec.adap, aux->cec.parent)) {
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cec_delete_adapter(aux->cec.adap);
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aux->cec.adap = NULL;
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} else {
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/*
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* Update the phys addr for the new CEC adapter. When called
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* from drm_dp_cec_register_connector() edid == NULL, so in
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* that case the phys addr is just invalidated.
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*/
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cec_s_phys_addr_from_edid(aux->cec.adap, edid);
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}
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unlock:
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mutex_unlock(&aux->cec.lock);
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}
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EXPORT_SYMBOL(drm_dp_cec_set_edid);
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/*
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* The EDID disappeared (likely because of the HPD going down).
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*/
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void drm_dp_cec_unset_edid(struct drm_dp_aux *aux)
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{
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/* No transfer function was set, so not a DP connector */
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if (!aux->transfer)
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return;
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cancel_delayed_work_sync(&aux->cec.unregister_work);
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mutex_lock(&aux->cec.lock);
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if (!aux->cec.adap)
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goto unlock;
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cec_phys_addr_invalidate(aux->cec.adap);
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/*
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* We're done if we want to keep the CEC device
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* (drm_dp_cec_unregister_delay is >= NEVER_UNREG_DELAY) or if the
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* DPCD still indicates the CEC capability (expected for an integrated
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* HDMI branch device).
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*/
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if (drm_dp_cec_unregister_delay < NEVER_UNREG_DELAY &&
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!drm_dp_cec_cap(aux, NULL)) {
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/*
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* Unregister the CEC adapter after drm_dp_cec_unregister_delay
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* seconds. This to debounce short HPD off-and-on cycles from
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* displays.
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*/
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schedule_delayed_work(&aux->cec.unregister_work,
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drm_dp_cec_unregister_delay * HZ);
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}
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unlock:
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mutex_unlock(&aux->cec.lock);
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}
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EXPORT_SYMBOL(drm_dp_cec_unset_edid);
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/**
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* drm_dp_cec_register_connector() - register a new connector
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* @aux: DisplayPort AUX channel
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* @name: name of the CEC device
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* @parent: parent device
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*
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* A new connector was registered with associated CEC adapter name and
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* CEC adapter parent device. After registering the name and parent
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* drm_dp_cec_set_edid() is called to check if the connector supports
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* CEC and to register a CEC adapter if that is the case.
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*/
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void drm_dp_cec_register_connector(struct drm_dp_aux *aux, const char *name,
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struct device *parent)
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{
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WARN_ON(aux->cec.adap);
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if (WARN_ON(!aux->transfer))
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return;
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aux->cec.name = name;
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aux->cec.parent = parent;
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INIT_DELAYED_WORK(&aux->cec.unregister_work,
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drm_dp_cec_unregister_work);
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}
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EXPORT_SYMBOL(drm_dp_cec_register_connector);
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/**
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* drm_dp_cec_unregister_connector() - unregister the CEC adapter, if any
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* @aux: DisplayPort AUX channel
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*/
|
|
void drm_dp_cec_unregister_connector(struct drm_dp_aux *aux)
|
|
{
|
|
if (!aux->cec.adap)
|
|
return;
|
|
cancel_delayed_work_sync(&aux->cec.unregister_work);
|
|
cec_unregister_adapter(aux->cec.adap);
|
|
aux->cec.adap = NULL;
|
|
}
|
|
EXPORT_SYMBOL(drm_dp_cec_unregister_connector);
|