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![Sam Ravnborg](/assets/img/avatar_default.png)
drmP.h is deprecated and will be deleted.
Replace use with proper header.
Divide header includes in blocks while touching these.
Build tested with various archtectures and configs.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Fixes: ae85b0df12
("drm_dp_cec: add connector info support.")
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Sean Paul <sean@poorly.run>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Dariusz Marcinkiewicz <darekm@google.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191007171224.1581-2-sam@ravnborg.org
451 lines
14 KiB
C
451 lines
14 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 <media/cec.h>
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#include <drm/drm_connector.h>
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#include <drm/drm_device.h>
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#include <drm/drm_dp_helper.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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struct drm_connector *connector = aux->cec.connector;
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u32 cec_caps = CEC_CAP_DEFAULTS | CEC_CAP_NEEDS_HPD |
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CEC_CAP_CONNECTOR_INFO;
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struct cec_connector_info conn_info;
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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, connector->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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cec_fill_conn_info_from_drm(&conn_info, connector);
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cec_s_conn_info(aux->cec.adap, &conn_info);
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if (cec_register_adapter(aux->cec.adap, connector->dev->dev)) {
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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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* @connector: drm connector
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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,
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struct drm_connector *connector)
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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.connector = connector;
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INIT_DELAYED_WORK(&aux->cec.unregister_work,
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drm_dp_cec_unregister_work);
|
|
}
|
|
EXPORT_SYMBOL(drm_dp_cec_register_connector);
|
|
|
|
/**
|
|
* drm_dp_cec_unregister_connector() - unregister the CEC adapter, if any
|
|
* @aux: DisplayPort AUX channel
|
|
*/
|
|
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);
|