1 .. SPDX-License-Identifier: GPL-2.0 1 .. SPDX-License-Identifier: GPL-2.0
2 2
3 ======== 3 ========
4 HDMI CEC 4 HDMI CEC
5 ======== 5 ========
6 6
7 Supported hardware in mainline 7 Supported hardware in mainline
8 ============================== 8 ==============================
9 9
10 HDMI Transmitters: 10 HDMI Transmitters:
11 11
12 - Exynos4 12 - Exynos4
13 - Exynos5 13 - Exynos5
14 - STIH4xx HDMI CEC 14 - STIH4xx HDMI CEC
15 - V4L2 adv7511 (same HW, but a different drive 15 - V4L2 adv7511 (same HW, but a different driver from the drm adv7511)
16 - stm32 16 - stm32
17 - Allwinner A10 (sun4i) 17 - Allwinner A10 (sun4i)
18 - Raspberry Pi 18 - Raspberry Pi
19 - dw-hdmi (Synopsis IP) 19 - dw-hdmi (Synopsis IP)
20 - amlogic (meson ao-cec and ao-cec-g12a) 20 - amlogic (meson ao-cec and ao-cec-g12a)
21 - drm adv7511/adv7533 21 - drm adv7511/adv7533
22 - omap4 22 - omap4
23 - tegra 23 - tegra
24 - rk3288, rk3399 24 - rk3288, rk3399
25 - tda998x 25 - tda998x
26 - DisplayPort CEC-Tunneling-over-AUX on i915, 26 - DisplayPort CEC-Tunneling-over-AUX on i915, nouveau and amdgpu
27 - ChromeOS EC CEC 27 - ChromeOS EC CEC
28 - CEC for SECO boards (UDOO x86). 28 - CEC for SECO boards (UDOO x86).
29 - Chrontel CH7322 29 - Chrontel CH7322
30 30
31 31
32 HDMI Receivers: 32 HDMI Receivers:
33 33
34 - adv7604/11/12 34 - adv7604/11/12
35 - adv7842 35 - adv7842
36 - tc358743 36 - tc358743
37 37
38 USB Dongles (see below for additional informat 38 USB Dongles (see below for additional information on how to use these
39 dongles): 39 dongles):
40 40
41 - Pulse-Eight: the pulse8-cec driver implement 41 - Pulse-Eight: the pulse8-cec driver implements the following module option:
42 ``persistent_config``: by default this is of 42 ``persistent_config``: by default this is off, but when set to 1 the driver
43 will store the current settings to the devic 43 will store the current settings to the device's internal eeprom and restore
44 it the next time the device is connected to 44 it the next time the device is connected to the USB port.
45 <<
46 - RainShadow Tech. Note: this driver does not 45 - RainShadow Tech. Note: this driver does not support the persistent_config
47 module option of the Pulse-Eight driver. The 46 module option of the Pulse-Eight driver. The hardware supports it, but I
48 have no plans to add this feature. But I acc 47 have no plans to add this feature. But I accept patches :-)
49 48
50 - Extron DA HD 4K PLUS HDMI Distribution Ampli <<
51 :ref:`extron_da_hd_4k_plus` for more informa <<
52 <<
53 Miscellaneous: 49 Miscellaneous:
54 50
55 - vivid: emulates a CEC receiver and CEC trans 51 - vivid: emulates a CEC receiver and CEC transmitter.
56 Can be used to test CEC applications without 52 Can be used to test CEC applications without actual CEC hardware.
57 53
58 - cec-gpio. If the CEC pin is hooked up to a G 54 - cec-gpio. If the CEC pin is hooked up to a GPIO pin then
59 you can control the CEC line through this dr 55 you can control the CEC line through this driver. This supports error
60 injection as well. 56 injection as well.
61 57
62 - cec-gpio and Allwinner A10 (or any other dri 58 - cec-gpio and Allwinner A10 (or any other driver that uses the CEC pin
63 framework to drive the CEC pin directly): th 59 framework to drive the CEC pin directly): the CEC pin framework uses
64 high-resolution timers. These timers are aff 60 high-resolution timers. These timers are affected by NTP daemons that
65 speed up or slow down the clock to sync with 61 speed up or slow down the clock to sync with the official time. The
66 chronyd server will by default increase or d 62 chronyd server will by default increase or decrease the clock by
67 1/12th. This will cause the CEC timings to g 63 1/12th. This will cause the CEC timings to go out of spec. To fix this,
68 add a 'maxslewrate 40000' line to chronyd.co 64 add a 'maxslewrate 40000' line to chronyd.conf. This limits the clock
69 frequency change to 1/25th, which keeps the 65 frequency change to 1/25th, which keeps the CEC timings within spec.
70 66
71 67
72 Utilities 68 Utilities
73 ========= 69 =========
74 70
75 Utilities are available here: https://git.linu 71 Utilities are available here: https://git.linuxtv.org/v4l-utils.git
76 72
77 ``utils/cec-ctl``: control a CEC device 73 ``utils/cec-ctl``: control a CEC device
78 74
79 ``utils/cec-compliance``: test compliance of a 75 ``utils/cec-compliance``: test compliance of a remote CEC device
80 76
81 ``utils/cec-follower``: emulate a CEC follower 77 ``utils/cec-follower``: emulate a CEC follower device
82 78
83 Note that ``cec-ctl`` has support for the CEC 79 Note that ``cec-ctl`` has support for the CEC Hospitality Profile as is
84 used in some hotel displays. See http://www.ht 80 used in some hotel displays. See http://www.htng.org.
85 81
86 Note that the libcec library (https://github.c 82 Note that the libcec library (https://github.com/Pulse-Eight/libcec) supports
87 the linux CEC framework. 83 the linux CEC framework.
88 84
89 If you want to get the CEC specification, then 85 If you want to get the CEC specification, then look at the References of
90 the HDMI wikipedia page: https://en.wikipedia. 86 the HDMI wikipedia page: https://en.wikipedia.org/wiki/HDMI. CEC is part
91 of the HDMI specification. HDMI 1.3 is freely 87 of the HDMI specification. HDMI 1.3 is freely available (very similar to
92 HDMI 1.4 w.r.t. CEC) and should be good enough 88 HDMI 1.4 w.r.t. CEC) and should be good enough for most things.
93 89
94 90
95 DisplayPort to HDMI Adapters with working CEC 91 DisplayPort to HDMI Adapters with working CEC
96 ============================================= 92 =============================================
97 93
98 Background: most adapters do not support the C 94 Background: most adapters do not support the CEC Tunneling feature,
99 and of those that do many did not actually con 95 and of those that do many did not actually connect the CEC pin.
100 Unfortunately, this means that while a CEC dev 96 Unfortunately, this means that while a CEC device is created, it
101 is actually all alone in the world and will ne 97 is actually all alone in the world and will never be able to see other
102 CEC devices. 98 CEC devices.
103 99
104 This is a list of known working adapters that 100 This is a list of known working adapters that have CEC Tunneling AND
105 that properly connected the CEC pin. If you fi 101 that properly connected the CEC pin. If you find adapters that work
106 but are not in this list, then drop me a note. 102 but are not in this list, then drop me a note.
107 103
108 To test: hook up your DP-to-HDMI adapter to a 104 To test: hook up your DP-to-HDMI adapter to a CEC capable device
109 (typically a TV), then run:: 105 (typically a TV), then run::
110 106
111 cec-ctl --playback # Configure th 107 cec-ctl --playback # Configure the PC as a CEC Playback device
112 cec-ctl -S # Show the CEC 108 cec-ctl -S # Show the CEC topology
113 109
114 The ``cec-ctl -S`` command should show at leas 110 The ``cec-ctl -S`` command should show at least two CEC devices,
115 ourselves and the CEC device you are connected 111 ourselves and the CEC device you are connected to (i.e. typically the TV).
116 112
117 General note: I have only seen this work with 113 General note: I have only seen this work with the Parade PS175, PS176 and
118 PS186 chipsets and the MegaChips 2900. While M 114 PS186 chipsets and the MegaChips 2900. While MegaChips 28x0 claims CEC support,
119 I have never seen it work. 115 I have never seen it work.
120 116
121 USB-C to HDMI 117 USB-C to HDMI
122 ------------- 118 -------------
123 119
124 Samsung Multiport Adapter EE-PW700: https://ww 120 Samsung Multiport Adapter EE-PW700: https://www.samsung.com/ie/support/model/EE-PW700BBEGWW/
125 121
126 Kramer ADC-U31C/HF: https://www.kramerav.com/p 122 Kramer ADC-U31C/HF: https://www.kramerav.com/product/ADC-U31C/HF
127 123
128 Club3D CAC-2504: https://www.club-3d.com/en/de 124 Club3D CAC-2504: https://www.club-3d.com/en/detail/2449/usb_3.1_type_c_to_hdmi_2.0_uhd_4k_60hz_active_adapter/
129 125
130 DisplayPort to HDMI 126 DisplayPort to HDMI
131 ------------------- 127 -------------------
132 128
133 Club3D CAC-1080: https://www.club-3d.com/en/de 129 Club3D CAC-1080: https://www.club-3d.com/en/detail/2442/displayport_1.4_to_hdmi_2.0b_hdr/
134 130
135 CableCreation (SKU: CD0712): https://www.cable 131 CableCreation (SKU: CD0712): https://www.cablecreation.com/products/active-displayport-to-hdmi-adapter-4k-hdr
136 132
137 HP DisplayPort to HDMI True 4k Adapter (P/N 2J 133 HP DisplayPort to HDMI True 4k Adapter (P/N 2JA63AA): https://www.hp.com/us-en/shop/pdp/hp-displayport-to-hdmi-true-4k-adapter
138 134
139 Mini-DisplayPort to HDMI 135 Mini-DisplayPort to HDMI
140 ------------------------ 136 ------------------------
141 137
142 Club3D CAC-1180: https://www.club-3d.com/en/de 138 Club3D CAC-1180: https://www.club-3d.com/en/detail/2443/mini_displayport_1.4_to_hdmi_2.0b_hdr/
143 139
144 Note that passive adapters will never work, yo 140 Note that passive adapters will never work, you need an active adapter.
145 141
146 The Club3D adapters in this list are all MegaC 142 The Club3D adapters in this list are all MegaChips 2900 based. Other Club3D adapters
147 are PS176 based and do NOT have the CEC pin ho 143 are PS176 based and do NOT have the CEC pin hooked up, so only the three Club3D
148 adapters above are known to work. 144 adapters above are known to work.
149 145
150 I suspect that MegaChips 2900 based designs in 146 I suspect that MegaChips 2900 based designs in general are likely to work
151 whereas with the PS176 it is more hit-and-miss 147 whereas with the PS176 it is more hit-and-miss (mostly miss). The PS186 is
152 likely to have the CEC pin hooked up, it looks 148 likely to have the CEC pin hooked up, it looks like they changed the reference
153 design for that chipset. 149 design for that chipset.
154 150
155 151
156 USB CEC Dongles 152 USB CEC Dongles
157 =============== 153 ===============
158 154
159 These dongles appear as ``/dev/ttyACMX`` devic 155 These dongles appear as ``/dev/ttyACMX`` devices and need the ``inputattach``
160 utility to create the ``/dev/cecX`` devices. S 156 utility to create the ``/dev/cecX`` devices. Support for the Pulse-Eight
161 has been added to ``inputattach`` 1.6.0. Suppo 157 has been added to ``inputattach`` 1.6.0. Support for the Rainshadow Tech has
162 been added to ``inputattach`` 1.6.1. 158 been added to ``inputattach`` 1.6.1.
163 159
164 You also need udev rules to automatically star 160 You also need udev rules to automatically start systemd services::
165 161
166 SUBSYSTEM=="tty", KERNEL=="ttyACM[0-9] 162 SUBSYSTEM=="tty", KERNEL=="ttyACM[0-9]*", ATTRS{idVendor}=="2548", ATTRS{idProduct}=="1002", ACTION=="add", TAG+="systemd", ENV{SYSTEMD_WANTS}+="pulse8-cec-inputattach@%k.service"
167 SUBSYSTEM=="tty", KERNEL=="ttyACM[0-9] 163 SUBSYSTEM=="tty", KERNEL=="ttyACM[0-9]*", ATTRS{idVendor}=="2548", ATTRS{idProduct}=="1001", ACTION=="add", TAG+="systemd", ENV{SYSTEMD_WANTS}+="pulse8-cec-inputattach@%k.service"
168 SUBSYSTEM=="tty", KERNEL=="ttyACM[0-9] 164 SUBSYSTEM=="tty", KERNEL=="ttyACM[0-9]*", ATTRS{idVendor}=="04d8", ATTRS{idProduct}=="ff59", ACTION=="add", TAG+="systemd", ENV{SYSTEMD_WANTS}+="rainshadow-cec-inputattach@%k.service"
169 165
170 and these systemd services: 166 and these systemd services:
171 167
172 For Pulse-Eight make /lib/systemd/system/pulse 168 For Pulse-Eight make /lib/systemd/system/pulse8-cec-inputattach@.service::
173 169
174 [Unit] 170 [Unit]
175 Description=inputattach for pulse8-cec 171 Description=inputattach for pulse8-cec device on %I
176 172
177 [Service] 173 [Service]
178 Type=simple 174 Type=simple
179 ExecStart=/usr/bin/inputattach --pulse 175 ExecStart=/usr/bin/inputattach --pulse8-cec /dev/%I
180 176
181 For the RainShadow Tech make /lib/systemd/syst 177 For the RainShadow Tech make /lib/systemd/system/rainshadow-cec-inputattach@.service::
182 178
183 [Unit] 179 [Unit]
184 Description=inputattach for rainshadow 180 Description=inputattach for rainshadow-cec device on %I
185 181
186 [Service] 182 [Service]
187 Type=simple 183 Type=simple
188 ExecStart=/usr/bin/inputattach --rains 184 ExecStart=/usr/bin/inputattach --rainshadow-cec /dev/%I
189 185
190 186
191 For proper suspend/resume support create: /lib 187 For proper suspend/resume support create: /lib/systemd/system/restart-cec-inputattach.service::
192 188
193 [Unit] 189 [Unit]
194 Description=restart inputattach for ce 190 Description=restart inputattach for cec devices
195 After=suspend.target 191 After=suspend.target
196 192
197 [Service] 193 [Service]
198 Type=forking 194 Type=forking
199 ExecStart=/bin/bash -c 'for d in /dev/ 195 ExecStart=/bin/bash -c 'for d in /dev/serial/by-id/usb-Pulse-Eight*; do /usr/bin/inputattach --daemon --pulse8-cec $d; done; for d in /dev/serial/by-id/usb-RainShadow_Tech*; do /usr/bin/inputattach --daemon --rainshadow-cec $d; done'
200 196
201 [Install] 197 [Install]
202 WantedBy=suspend.target 198 WantedBy=suspend.target
203 199
204 And run ``systemctl enable restart-cec-inputat 200 And run ``systemctl enable restart-cec-inputattach``.
205 201
206 To automatically set the physical address of t 202 To automatically set the physical address of the CEC device whenever the
207 EDID changes, you can use ``cec-ctl`` with the 203 EDID changes, you can use ``cec-ctl`` with the ``-E`` option::
208 204
209 cec-ctl -E /sys/class/drm/card0-DP-1/e 205 cec-ctl -E /sys/class/drm/card0-DP-1/edid
210 206
211 This assumes the dongle is connected to the ca 207 This assumes the dongle is connected to the card0-DP-1 output (``xrandr`` will tell
212 you which output is used) and it will poll for 208 you which output is used) and it will poll for changes to the EDID and update
213 the Physical Address whenever they occur. 209 the Physical Address whenever they occur.
214 210
215 To automatically run this command you can use 211 To automatically run this command you can use cron. Edit crontab with
216 ``crontab -e`` and add this line:: 212 ``crontab -e`` and add this line::
217 213
218 @reboot /usr/local/bin/cec-ctl -E /sys 214 @reboot /usr/local/bin/cec-ctl -E /sys/class/drm/card0-DP-1/edid
219 215
220 This only works for display drivers that expos 216 This only works for display drivers that expose the EDID in ``/sys/class/drm``,
221 such as the i915 driver. 217 such as the i915 driver.
222 218
223 219
224 CEC Without HPD 220 CEC Without HPD
225 =============== 221 ===============
226 222
227 Some displays when in standby mode have no HDM 223 Some displays when in standby mode have no HDMI Hotplug Detect signal, but
228 CEC is still enabled so connected devices can 224 CEC is still enabled so connected devices can send an <Image View On> CEC
229 message in order to wake up such displays. Unf 225 message in order to wake up such displays. Unfortunately, not all CEC
230 adapters can support this. An example is the O 226 adapters can support this. An example is the Odroid-U3 SBC that has a
231 level-shifter that is powered off when the HPD 227 level-shifter that is powered off when the HPD signal is low, thus
232 blocking the CEC pin. Even though the SoC can 228 blocking the CEC pin. Even though the SoC can use CEC without a HPD,
233 the level-shifter will prevent this from funct 229 the level-shifter will prevent this from functioning.
234 230
235 There is a CEC capability flag to signal this: 231 There is a CEC capability flag to signal this: ``CEC_CAP_NEEDS_HPD``.
236 If set, then the hardware cannot wake up displ 232 If set, then the hardware cannot wake up displays with this behavior.
237 233
238 Note for CEC application implementers: the <Im 234 Note for CEC application implementers: the <Image View On> message must
239 be the first message you send, don't send any 235 be the first message you send, don't send any other messages before.
240 Certain very bad but unfortunately not uncommo 236 Certain very bad but unfortunately not uncommon CEC implementations
241 get very confused if they receive anything els 237 get very confused if they receive anything else but this message and
242 they won't wake up. 238 they won't wake up.
243 239
244 When writing a driver it can be tricky to test 240 When writing a driver it can be tricky to test this. There are two
245 ways to do this: 241 ways to do this:
246 242
247 1) Get a Pulse-Eight USB CEC dongle, connect a 243 1) Get a Pulse-Eight USB CEC dongle, connect an HDMI cable from your
248 device to the Pulse-Eight, but do not conne 244 device to the Pulse-Eight, but do not connect the Pulse-Eight to
249 the display. 245 the display.
250 246
251 Now configure the Pulse-Eight dongle:: 247 Now configure the Pulse-Eight dongle::
252 248
253 cec-ctl -p0.0.0.0 --tv 249 cec-ctl -p0.0.0.0 --tv
254 250
255 and start monitoring:: 251 and start monitoring::
256 252
257 sudo cec-ctl -M 253 sudo cec-ctl -M
258 254
259 On the device you are testing run:: 255 On the device you are testing run::
260 256
261 cec-ctl --playback 257 cec-ctl --playback
262 258
263 It should report a physical address of f.f. 259 It should report a physical address of f.f.f.f. Now run this
264 command:: 260 command::
265 261
266 cec-ctl -t0 --image-view-on 262 cec-ctl -t0 --image-view-on
267 263
268 The Pulse-Eight should see the <Image View 264 The Pulse-Eight should see the <Image View On> message. If not,
269 then something (hardware and/or software) i 265 then something (hardware and/or software) is preventing the CEC
270 message from going out. 266 message from going out.
271 267
272 To make sure you have the wiring correct ju 268 To make sure you have the wiring correct just connect the
273 Pulse-Eight to a CEC-enabled display and ru 269 Pulse-Eight to a CEC-enabled display and run the same command
274 on your device: now there is a HPD, so you 270 on your device: now there is a HPD, so you should see the command
275 arriving at the Pulse-Eight. 271 arriving at the Pulse-Eight.
276 272
277 2) If you have another linux device supporting 273 2) If you have another linux device supporting CEC without HPD, then
278 you can just connect your device to that de 274 you can just connect your device to that device. Yes, you can connect
279 two HDMI outputs together. You won't have a 275 two HDMI outputs together. You won't have a HPD (which is what we
280 want for this test), but the second device 276 want for this test), but the second device can monitor the CEC pin.
281 277
282 Otherwise use the same commands as in 1. 278 Otherwise use the same commands as in 1.
283 279
284 If CEC messages do not come through when there 280 If CEC messages do not come through when there is no HPD, then you
285 need to figure out why. Typically it is either 281 need to figure out why. Typically it is either a hardware restriction
286 or the software powers off the CEC core when t 282 or the software powers off the CEC core when the HPD goes low. The
287 first cannot be corrected of course, the secon 283 first cannot be corrected of course, the second will likely required
288 driver changes. 284 driver changes.
289 285
290 286
291 Microcontrollers & CEC 287 Microcontrollers & CEC
292 ====================== 288 ======================
293 289
294 We have seen some CEC implementations in displ 290 We have seen some CEC implementations in displays that use a microcontroller
295 to sample the bus. This does not have to be a 291 to sample the bus. This does not have to be a problem, but some implementations
296 have timing issues. This is hard to discover u 292 have timing issues. This is hard to discover unless you can hook up a low-level
297 CEC debugger (see the next section). 293 CEC debugger (see the next section).
298 294
299 You will see cases where the CEC transmitter h 295 You will see cases where the CEC transmitter holds the CEC line high or low for
300 a longer time than is allowed. For directed me 296 a longer time than is allowed. For directed messages this is not a problem since
301 if that happens the message will not be Acked 297 if that happens the message will not be Acked and it will be retransmitted.
302 For broadcast messages no such mechanism exist 298 For broadcast messages no such mechanism exists.
303 299
304 It's not clear what to do about this. It is pr 300 It's not clear what to do about this. It is probably wise to transmit some
305 broadcast messages twice to reduce the chance 301 broadcast messages twice to reduce the chance of them being lost. Specifically
306 <Standby> and <Active Source> are candidates f 302 <Standby> and <Active Source> are candidates for that.
307 303
308 304
309 Making a CEC debugger 305 Making a CEC debugger
310 ===================== 306 =====================
311 307
312 By using a Raspberry Pi 4B and some cheap comp 308 By using a Raspberry Pi 4B and some cheap components you can make
313 your own low-level CEC debugger. 309 your own low-level CEC debugger.
314 310
315 The critical component is one of these HDMI fe 311 The critical component is one of these HDMI female-female passthrough connectors
316 (full soldering type 1): 312 (full soldering type 1):
317 313
318 https://elabbay.myshopify.com/collections/came 314 https://elabbay.myshopify.com/collections/camera/products/hdmi-af-af-v1a-hdmi-type-a-female-to-hdmi-type-a-female-pass-through-adapter-breakout-board?variant=45533926147
319 315
320 The video quality is variable and certainly no 316 The video quality is variable and certainly not enough to pass-through 4kp60
321 (594 MHz) video. You might be able to support 317 (594 MHz) video. You might be able to support 4kp30, but more likely you will
322 be limited to 1080p60 (148.5 MHz). But for CEC 318 be limited to 1080p60 (148.5 MHz). But for CEC testing that is fine.
323 319
324 You need a breadboard and some breadboard wire 320 You need a breadboard and some breadboard wires:
325 321
326 http://www.dx.com/p/diy-40p-male-to-female-mal 322 http://www.dx.com/p/diy-40p-male-to-female-male-to-male-female-to-female-dupont-line-wire-3pcs-356089#.WYLOOXWGN7I
327 323
328 If you want to monitor the HPD and/or 5V lines 324 If you want to monitor the HPD and/or 5V lines as well, then you need one of
329 these 5V to 3.3V level shifters: 325 these 5V to 3.3V level shifters:
330 326
331 https://www.adafruit.com/product/757 327 https://www.adafruit.com/product/757
332 328
333 (This is just where I got these components, th 329 (This is just where I got these components, there are many other places you
334 can get similar things). 330 can get similar things).
335 331
336 The ground pin of the HDMI connector needs to 332 The ground pin of the HDMI connector needs to be connected to a ground
337 pin of the Raspberry Pi, of course. 333 pin of the Raspberry Pi, of course.
338 334
339 The CEC pin of the HDMI connector needs to be 335 The CEC pin of the HDMI connector needs to be connected to these pins:
340 GPIO 6 and GPIO 7. The optional HPD pin of the 336 GPIO 6 and GPIO 7. The optional HPD pin of the HDMI connector should
341 be connected via the level shifter to these pi 337 be connected via the level shifter to these pins: GPIO 23 and GPIO 12.
342 The optional 5V pin of the HDMI connector shou 338 The optional 5V pin of the HDMI connector should be connected via the
343 level shifter to these pins: GPIO 25 and GPIO 339 level shifter to these pins: GPIO 25 and GPIO 22. Monitoring the HPD and
344 5V lines is not necessary, but it is helpful. 340 5V lines is not necessary, but it is helpful.
345 341
346 This device tree addition in ``arch/arm/boot/d 342 This device tree addition in ``arch/arm/boot/dts/bcm2711-rpi-4-b.dts``
347 will hook up the cec-gpio driver correctly:: 343 will hook up the cec-gpio driver correctly::
348 344
349 cec@6 { 345 cec@6 {
350 compatible = "cec-gpio"; 346 compatible = "cec-gpio";
351 cec-gpios = <&gpio 6 (GPIO_ACT 347 cec-gpios = <&gpio 6 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
352 hpd-gpios = <&gpio 23 GPIO_ACT 348 hpd-gpios = <&gpio 23 GPIO_ACTIVE_HIGH>;
353 v5-gpios = <&gpio 25 GPIO_ACTI 349 v5-gpios = <&gpio 25 GPIO_ACTIVE_HIGH>;
354 }; 350 };
355 351
356 cec@7 { 352 cec@7 {
357 compatible = "cec-gpio"; 353 compatible = "cec-gpio";
358 cec-gpios = <&gpio 7 (GPIO_ACT 354 cec-gpios = <&gpio 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
359 hpd-gpios = <&gpio 12 GPIO_ACT 355 hpd-gpios = <&gpio 12 GPIO_ACTIVE_HIGH>;
360 v5-gpios = <&gpio 22 GPIO_ACTI 356 v5-gpios = <&gpio 22 GPIO_ACTIVE_HIGH>;
361 }; 357 };
362 358
363 If you haven't hooked up the HPD and/or 5V lin 359 If you haven't hooked up the HPD and/or 5V lines, then just delete those
364 lines. 360 lines.
365 361
366 This dts change will enable two cec GPIO devic 362 This dts change will enable two cec GPIO devices: I typically use one to
367 send/receive CEC commands and the other to mon 363 send/receive CEC commands and the other to monitor. If you monitor using
368 an unconfigured CEC adapter then it will use G 364 an unconfigured CEC adapter then it will use GPIO interrupts which makes
369 monitoring very accurate. 365 monitoring very accurate.
370 366
371 If you just want to monitor traffic, then a si 367 If you just want to monitor traffic, then a single instance is sufficient.
372 The minimum configuration is one HDMI female-f 368 The minimum configuration is one HDMI female-female passthrough connector
373 and two female-female breadboard wires: one fo 369 and two female-female breadboard wires: one for connecting the HDMI ground
374 pin to a ground pin on the Raspberry Pi, and t 370 pin to a ground pin on the Raspberry Pi, and the other to connect the HDMI
375 CEC pin to GPIO 6 on the Raspberry Pi. 371 CEC pin to GPIO 6 on the Raspberry Pi.
376 372
377 The documentation on how to use the error inje 373 The documentation on how to use the error injection is here: :ref:`cec_pin_error_inj`.
378 374
379 ``cec-ctl --monitor-pin`` will do low-level CE 375 ``cec-ctl --monitor-pin`` will do low-level CEC bus sniffing and analysis.
380 You can also store the CEC traffic to file usi 376 You can also store the CEC traffic to file using ``--store-pin`` and analyze
381 it later using ``--analyze-pin``. 377 it later using ``--analyze-pin``.
382 378
383 You can also use this as a full-fledged CEC de 379 You can also use this as a full-fledged CEC device by configuring it
384 using ``cec-ctl --tv -p0.0.0.0`` or ``cec-ctl 380 using ``cec-ctl --tv -p0.0.0.0`` or ``cec-ctl --playback -p1.0.0.0``.
385 <<
386 .. _extron_da_hd_4k_plus: <<
387 <<
388 Extron DA HD 4K PLUS CEC Adapter driver <<
389 ======================================= <<
390 <<
391 This driver is for the Extron DA HD 4K PLUS se <<
392 Amplifiers: https://www.extron.com/product/dah <<
393 <<
394 The 2, 4 and 6 port models are supported. <<
395 <<
396 Firmware version 1.02.0001 or higher is requir <<
397 <<
398 Note that older Extron hardware revisions have <<
399 which may mean that CEC will not work. This is <<
400 E34814 and up. <<
401 <<
402 The CEC support has two modes: the first is a <<
403 to manually control CEC for the HDMI Input and <<
404 full control, it is also complicated. <<
405 <<
406 The second mode is an automatic mode, which is <<
407 ``vendor_id`` is set. In that case the driver <<
408 received in the input will be distributed to t <<
409 to use the /dev/cecX devices to talk to the co <<
410 the driver that configures everything and deal <<
411 changes. <<
412 <<
413 The driver also takes care of the EDIDs: /dev/ <<
414 read the EDIDs and (for the HDMI Input port) t <<
415 <<
416 By default userspace is responsible to set the <<
417 according to the EDIDs of the connected displa <<
418 module option is set, then the driver will tak <<
419 of the HDMI Input based on the supported resol <<
420 Currently the driver only supports resolutions <<
421 displays support 4kp60, then it will advertise <<
422 it will fall back to an EDID that just reports <<
423 <<
424 The status of the Extron is reported in ``/sys <<
425 <<
426 The extron-da-hd-4k-plus driver implements the <<
427 <<
428 ``debug`` <<
429 --------- <<
430 <<
431 If set to 1, then all serial port traffic is s <<
432 <<
433 ``vendor_id`` <<
434 ------------- <<
435 <<
436 The CEC Vendor ID to report to connected displ <<
437 <<
438 If set, then the driver will take care of dist <<
439 on the input to the HDMI outputs. This is done <<
440 <<
441 - <Standby> <<
442 - <Image View On> and <Text View On> <<
443 - <Give Device Power Status> <<
444 - <Set System Audio Mode> <<
445 - <Request Current Latency> <<
446 <<
447 If not set, then userspace is responsible for <<
448 configure the CEC devices for HDMI Input and t <<
449 <<
450 ``manufacturer_name`` <<
451 --------------------- <<
452 <<
453 A three character manufacturer name that is us <<
454 Input. If not set, then userspace is reponsibl <<
455 If set, then the driver will update the EDID a <<
456 resolutions supported by the connected display <<
457 anymore to manually set the EDID for the HDMI <<
458 <<
459 ``hpd_never_low`` <<
460 ----------------- <<
461 <<
462 If set, then the Hotplug Detect pin of the HDM <<
463 even if nothing is connected to the HDMI Outpu <<
464 then the Hotplug Detect pin of the HDMI input <<
465 Hotplug Detect pins of the HDMI Outputs are al <<
466 <<
467 This option may be changed dynamically. <<
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