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 <<
63 framework to drive the CEC pin directly): th <<
64 high-resolution timers. These timers are aff <<
65 speed up or slow down the clock to sync with <<
66 chronyd server will by default increase or d <<
67 1/12th. This will cause the CEC timings to g <<
68 add a 'maxslewrate 40000' line to chronyd.co <<
69 frequency change to 1/25th, which keeps the <<
70 <<
71 58
72 Utilities 59 Utilities
73 ========= 60 =========
74 61
75 Utilities are available here: https://git.linu 62 Utilities are available here: https://git.linuxtv.org/v4l-utils.git
76 63
77 ``utils/cec-ctl``: control a CEC device 64 ``utils/cec-ctl``: control a CEC device
78 65
79 ``utils/cec-compliance``: test compliance of a 66 ``utils/cec-compliance``: test compliance of a remote CEC device
80 67
81 ``utils/cec-follower``: emulate a CEC follower 68 ``utils/cec-follower``: emulate a CEC follower device
82 69
83 Note that ``cec-ctl`` has support for the CEC 70 Note that ``cec-ctl`` has support for the CEC Hospitality Profile as is
84 used in some hotel displays. See http://www.ht 71 used in some hotel displays. See http://www.htng.org.
85 72
86 Note that the libcec library (https://github.c 73 Note that the libcec library (https://github.com/Pulse-Eight/libcec) supports
87 the linux CEC framework. 74 the linux CEC framework.
88 75
89 If you want to get the CEC specification, then 76 If you want to get the CEC specification, then look at the References of
90 the HDMI wikipedia page: https://en.wikipedia. 77 the HDMI wikipedia page: https://en.wikipedia.org/wiki/HDMI. CEC is part
91 of the HDMI specification. HDMI 1.3 is freely 78 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 79 HDMI 1.4 w.r.t. CEC) and should be good enough for most things.
93 80
94 81
95 DisplayPort to HDMI Adapters with working CEC 82 DisplayPort to HDMI Adapters with working CEC
96 ============================================= 83 =============================================
97 84
98 Background: most adapters do not support the C 85 Background: most adapters do not support the CEC Tunneling feature,
99 and of those that do many did not actually con 86 and of those that do many did not actually connect the CEC pin.
100 Unfortunately, this means that while a CEC dev 87 Unfortunately, this means that while a CEC device is created, it
101 is actually all alone in the world and will ne 88 is actually all alone in the world and will never be able to see other
102 CEC devices. 89 CEC devices.
103 90
104 This is a list of known working adapters that 91 This is a list of known working adapters that have CEC Tunneling AND
105 that properly connected the CEC pin. If you fi 92 that properly connected the CEC pin. If you find adapters that work
106 but are not in this list, then drop me a note. 93 but are not in this list, then drop me a note.
107 94
108 To test: hook up your DP-to-HDMI adapter to a 95 To test: hook up your DP-to-HDMI adapter to a CEC capable device
109 (typically a TV), then run:: 96 (typically a TV), then run::
110 97
111 cec-ctl --playback # Configure th 98 cec-ctl --playback # Configure the PC as a CEC Playback device
112 cec-ctl -S # Show the CEC 99 cec-ctl -S # Show the CEC topology
113 100
114 The ``cec-ctl -S`` command should show at leas 101 The ``cec-ctl -S`` command should show at least two CEC devices,
115 ourselves and the CEC device you are connected 102 ourselves and the CEC device you are connected to (i.e. typically the TV).
116 103
117 General note: I have only seen this work with 104 General note: I have only seen this work with the Parade PS175, PS176 and
118 PS186 chipsets and the MegaChips 2900. While M 105 PS186 chipsets and the MegaChips 2900. While MegaChips 28x0 claims CEC support,
119 I have never seen it work. 106 I have never seen it work.
120 107
121 USB-C to HDMI 108 USB-C to HDMI
122 ------------- 109 -------------
123 110
124 Samsung Multiport Adapter EE-PW700: https://ww 111 Samsung Multiport Adapter EE-PW700: https://www.samsung.com/ie/support/model/EE-PW700BBEGWW/
125 112
126 Kramer ADC-U31C/HF: https://www.kramerav.com/p 113 Kramer ADC-U31C/HF: https://www.kramerav.com/product/ADC-U31C/HF
127 114
128 Club3D CAC-2504: https://www.club-3d.com/en/de 115 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/
129 116
130 DisplayPort to HDMI 117 DisplayPort to HDMI
131 ------------------- 118 -------------------
132 119
133 Club3D CAC-1080: https://www.club-3d.com/en/de 120 Club3D CAC-1080: https://www.club-3d.com/en/detail/2442/displayport_1.4_to_hdmi_2.0b_hdr/
134 121
135 CableCreation (SKU: CD0712): https://www.cable 122 CableCreation (SKU: CD0712): https://www.cablecreation.com/products/active-displayport-to-hdmi-adapter-4k-hdr
136 123
137 HP DisplayPort to HDMI True 4k Adapter (P/N 2J 124 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
138 125
139 Mini-DisplayPort to HDMI 126 Mini-DisplayPort to HDMI
140 ------------------------ 127 ------------------------
141 128
142 Club3D CAC-1180: https://www.club-3d.com/en/de 129 Club3D CAC-1180: https://www.club-3d.com/en/detail/2443/mini_displayport_1.4_to_hdmi_2.0b_hdr/
143 130
144 Note that passive adapters will never work, yo 131 Note that passive adapters will never work, you need an active adapter.
145 132
146 The Club3D adapters in this list are all MegaC 133 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 134 are PS176 based and do NOT have the CEC pin hooked up, so only the three Club3D
148 adapters above are known to work. 135 adapters above are known to work.
149 136
150 I suspect that MegaChips 2900 based designs in 137 I suspect that MegaChips 2900 based designs in general are likely to work
151 whereas with the PS176 it is more hit-and-miss 138 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 139 likely to have the CEC pin hooked up, it looks like they changed the reference
153 design for that chipset. 140 design for that chipset.
154 141
155 142
156 USB CEC Dongles 143 USB CEC Dongles
157 =============== 144 ===============
158 145
159 These dongles appear as ``/dev/ttyACMX`` devic 146 These dongles appear as ``/dev/ttyACMX`` devices and need the ``inputattach``
160 utility to create the ``/dev/cecX`` devices. S 147 utility to create the ``/dev/cecX`` devices. Support for the Pulse-Eight
161 has been added to ``inputattach`` 1.6.0. Suppo 148 has been added to ``inputattach`` 1.6.0. Support for the Rainshadow Tech has
162 been added to ``inputattach`` 1.6.1. 149 been added to ``inputattach`` 1.6.1.
163 150
164 You also need udev rules to automatically star 151 You also need udev rules to automatically start systemd services::
165 152
166 SUBSYSTEM=="tty", KERNEL=="ttyACM[0-9] 153 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] 154 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] 155 SUBSYSTEM=="tty", KERNEL=="ttyACM[0-9]*", ATTRS{idVendor}=="04d8", ATTRS{idProduct}=="ff59", ACTION=="add", TAG+="systemd", ENV{SYSTEMD_WANTS}+="rainshadow-cec-inputattach@%k.service"
169 156
170 and these systemd services: 157 and these systemd services:
171 158
172 For Pulse-Eight make /lib/systemd/system/pulse 159 For Pulse-Eight make /lib/systemd/system/pulse8-cec-inputattach@.service::
173 160
174 [Unit] 161 [Unit]
175 Description=inputattach for pulse8-cec 162 Description=inputattach for pulse8-cec device on %I
176 163
177 [Service] 164 [Service]
178 Type=simple 165 Type=simple
179 ExecStart=/usr/bin/inputattach --pulse 166 ExecStart=/usr/bin/inputattach --pulse8-cec /dev/%I
180 167
181 For the RainShadow Tech make /lib/systemd/syst 168 For the RainShadow Tech make /lib/systemd/system/rainshadow-cec-inputattach@.service::
182 169
183 [Unit] 170 [Unit]
184 Description=inputattach for rainshadow 171 Description=inputattach for rainshadow-cec device on %I
185 172
186 [Service] 173 [Service]
187 Type=simple 174 Type=simple
188 ExecStart=/usr/bin/inputattach --rains 175 ExecStart=/usr/bin/inputattach --rainshadow-cec /dev/%I
189 176
190 177
191 For proper suspend/resume support create: /lib 178 For proper suspend/resume support create: /lib/systemd/system/restart-cec-inputattach.service::
192 179
193 [Unit] 180 [Unit]
194 Description=restart inputattach for ce 181 Description=restart inputattach for cec devices
195 After=suspend.target 182 After=suspend.target
196 183
197 [Service] 184 [Service]
198 Type=forking 185 Type=forking
199 ExecStart=/bin/bash -c 'for d in /dev/ 186 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'
200 187
201 [Install] 188 [Install]
202 WantedBy=suspend.target 189 WantedBy=suspend.target
203 190
204 And run ``systemctl enable restart-cec-inputat 191 And run ``systemctl enable restart-cec-inputattach``.
205 192
206 To automatically set the physical address of t 193 To automatically set the physical address of the CEC device whenever the
207 EDID changes, you can use ``cec-ctl`` with the 194 EDID changes, you can use ``cec-ctl`` with the ``-E`` option::
208 195
209 cec-ctl -E /sys/class/drm/card0-DP-1/e 196 cec-ctl -E /sys/class/drm/card0-DP-1/edid
210 197
211 This assumes the dongle is connected to the ca 198 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 199 you which output is used) and it will poll for changes to the EDID and update
213 the Physical Address whenever they occur. 200 the Physical Address whenever they occur.
214 201
215 To automatically run this command you can use 202 To automatically run this command you can use cron. Edit crontab with
216 ``crontab -e`` and add this line:: 203 ``crontab -e`` and add this line::
217 204
218 @reboot /usr/local/bin/cec-ctl -E /sys 205 @reboot /usr/local/bin/cec-ctl -E /sys/class/drm/card0-DP-1/edid
219 206
220 This only works for display drivers that expos 207 This only works for display drivers that expose the EDID in ``/sys/class/drm``,
221 such as the i915 driver. 208 such as the i915 driver.
222 209
223 210
224 CEC Without HPD 211 CEC Without HPD
225 =============== 212 ===============
226 213
227 Some displays when in standby mode have no HDM 214 Some displays when in standby mode have no HDMI Hotplug Detect signal, but
228 CEC is still enabled so connected devices can 215 CEC is still enabled so connected devices can send an <Image View On> CEC
229 message in order to wake up such displays. Unf 216 message in order to wake up such displays. Unfortunately, not all CEC
230 adapters can support this. An example is the O 217 adapters can support this. An example is the Odroid-U3 SBC that has a
231 level-shifter that is powered off when the HPD 218 level-shifter that is powered off when the HPD signal is low, thus
232 blocking the CEC pin. Even though the SoC can 219 blocking the CEC pin. Even though the SoC can use CEC without a HPD,
233 the level-shifter will prevent this from funct 220 the level-shifter will prevent this from functioning.
234 221
235 There is a CEC capability flag to signal this: 222 There is a CEC capability flag to signal this: ``CEC_CAP_NEEDS_HPD``.
236 If set, then the hardware cannot wake up displ 223 If set, then the hardware cannot wake up displays with this behavior.
237 224
238 Note for CEC application implementers: the <Im 225 Note for CEC application implementers: the <Image View On> message must
239 be the first message you send, don't send any 226 be the first message you send, don't send any other messages before.
240 Certain very bad but unfortunately not uncommo 227 Certain very bad but unfortunately not uncommon CEC implementations
241 get very confused if they receive anything els 228 get very confused if they receive anything else but this message and
242 they won't wake up. 229 they won't wake up.
243 230
244 When writing a driver it can be tricky to test 231 When writing a driver it can be tricky to test this. There are two
245 ways to do this: 232 ways to do this:
246 233
247 1) Get a Pulse-Eight USB CEC dongle, connect a 234 1) Get a Pulse-Eight USB CEC dongle, connect an HDMI cable from your
248 device to the Pulse-Eight, but do not conne 235 device to the Pulse-Eight, but do not connect the Pulse-Eight to
249 the display. 236 the display.
250 237
251 Now configure the Pulse-Eight dongle:: 238 Now configure the Pulse-Eight dongle::
252 239
253 cec-ctl -p0.0.0.0 --tv 240 cec-ctl -p0.0.0.0 --tv
254 241
255 and start monitoring:: 242 and start monitoring::
256 243
257 sudo cec-ctl -M 244 sudo cec-ctl -M
258 245
259 On the device you are testing run:: 246 On the device you are testing run::
260 247
261 cec-ctl --playback 248 cec-ctl --playback
262 249
263 It should report a physical address of f.f. 250 It should report a physical address of f.f.f.f. Now run this
264 command:: 251 command::
265 252
266 cec-ctl -t0 --image-view-on 253 cec-ctl -t0 --image-view-on
267 254
268 The Pulse-Eight should see the <Image View 255 The Pulse-Eight should see the <Image View On> message. If not,
269 then something (hardware and/or software) i 256 then something (hardware and/or software) is preventing the CEC
270 message from going out. 257 message from going out.
271 258
272 To make sure you have the wiring correct ju 259 To make sure you have the wiring correct just connect the
273 Pulse-Eight to a CEC-enabled display and ru 260 Pulse-Eight to a CEC-enabled display and run the same command
274 on your device: now there is a HPD, so you 261 on your device: now there is a HPD, so you should see the command
275 arriving at the Pulse-Eight. 262 arriving at the Pulse-Eight.
276 263
277 2) If you have another linux device supporting 264 2) If you have another linux device supporting CEC without HPD, then
278 you can just connect your device to that de 265 you can just connect your device to that device. Yes, you can connect
279 two HDMI outputs together. You won't have a 266 two HDMI outputs together. You won't have a HPD (which is what we
280 want for this test), but the second device 267 want for this test), but the second device can monitor the CEC pin.
281 268
282 Otherwise use the same commands as in 1. 269 Otherwise use the same commands as in 1.
283 270
284 If CEC messages do not come through when there 271 If CEC messages do not come through when there is no HPD, then you
285 need to figure out why. Typically it is either 272 need to figure out why. Typically it is either a hardware restriction
286 or the software powers off the CEC core when t 273 or the software powers off the CEC core when the HPD goes low. The
287 first cannot be corrected of course, the secon 274 first cannot be corrected of course, the second will likely required
288 driver changes. 275 driver changes.
289 276
290 277
291 Microcontrollers & CEC 278 Microcontrollers & CEC
292 ====================== 279 ======================
293 280
294 We have seen some CEC implementations in displ 281 We have seen some CEC implementations in displays that use a microcontroller
295 to sample the bus. This does not have to be a 282 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 283 have timing issues. This is hard to discover unless you can hook up a low-level
297 CEC debugger (see the next section). 284 CEC debugger (see the next section).
298 285
299 You will see cases where the CEC transmitter h 286 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 287 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 288 if that happens the message will not be Acked and it will be retransmitted.
302 For broadcast messages no such mechanism exist 289 For broadcast messages no such mechanism exists.
303 290
304 It's not clear what to do about this. It is pr 291 It's not clear what to do about this. It is probably wise to transmit some
305 broadcast messages twice to reduce the chance 292 broadcast messages twice to reduce the chance of them being lost. Specifically
306 <Standby> and <Active Source> are candidates f 293 <Standby> and <Active Source> are candidates for that.
307 294
308 295
309 Making a CEC debugger 296 Making a CEC debugger
310 ===================== 297 =====================
311 298
312 By using a Raspberry Pi 4B and some cheap comp !! 299 By using a Raspberry Pi 2B/3/4 and some cheap components you can make
313 your own low-level CEC debugger. 300 your own low-level CEC debugger.
314 301
315 The critical component is one of these HDMI fe !! 302 Here is a picture of my setup:
316 (full soldering type 1): !! 303
>> 304 https://hverkuil.home.xs4all.nl/rpi3-cec.jpg
>> 305
>> 306 It's a Raspberry Pi 3 together with a breadboard and some breadboard wires:
>> 307
>> 308 http://www.dx.com/p/diy-40p-male-to-female-male-to-male-female-to-female-dupont-line-wire-3pcs-356089#.WYLOOXWGN7I
>> 309
>> 310 Finally on of these HDMI female-female passthrough connectors (full soldering type 1):
317 311
318 https://elabbay.myshopify.com/collections/came 312 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
319 313
320 The video quality is variable and certainly no !! 314 We've tested this and it works up to 4kp30 (297 MHz). The quality is not high
321 (594 MHz) video. You might be able to support !! 315 enough to pass-through 4kp60 (594 MHz).
322 be limited to 1080p60 (148.5 MHz). But for CEC <<
323 316
324 You need a breadboard and some breadboard wire !! 317 I also added an RTC and a breakout shield:
325 318
326 http://www.dx.com/p/diy-40p-male-to-female-mal !! 319 https://www.amazon.com/Makerfire%C2%AE-Raspberry-Module-DS1307-Battery/dp/B00ZOXWHK4
>> 320
>> 321 https://www.dx.com/p/raspberry-pi-gpio-expansion-board-breadboard-easy-multiplexing-board-one-to-three-with-screw-for-raspberry-pi-2-3-b-b-2729992.html#.YGRCG0MzZ7I
327 322
328 If you want to monitor the HPD and/or 5V lines !! 323 These two are not needed but they make life a bit easier.
329 these 5V to 3.3V level shifters: !! 324
>> 325 If you want to monitor the HPD line as well, then you need one of these
>> 326 level shifters:
330 327
331 https://www.adafruit.com/product/757 328 https://www.adafruit.com/product/757
332 329
333 (This is just where I got these components, th 330 (This is just where I got these components, there are many other places you
334 can get similar things). 331 can get similar things).
335 332
336 The ground pin of the HDMI connector needs to <<
337 pin of the Raspberry Pi, of course. <<
338 <<
339 The CEC pin of the HDMI connector needs to be 333 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 !! 334 CE0/IO8 and CE1/IO7 (pull-up GPIOs). The (optional) HPD pin of the HDMI
341 be connected via the level shifter to these pi !! 335 connector should be connected (via a level shifter to convert the 5V
342 The optional 5V pin of the HDMI connector shou !! 336 to 3.3V) to these pins: IO17 and IO27. The (optional) 5V pin of the HDMI
343 level shifter to these pins: GPIO 25 and GPIO !! 337 connector should be connected (via a level shifter) to these pins: IO22
344 5V lines is not necessary, but it is helpful. !! 338 and IO24. Monitoring the HPD an 5V lines is not necessary, but it is helpful.
345 <<
346 This device tree addition in ``arch/arm/boot/d <<
347 will hook up the cec-gpio driver correctly:: <<
348 339
349 cec@6 { !! 340 This kernel patch will hook up the cec-gpio driver correctly to
350 compatible = "cec-gpio"; !! 341 e.g. ``arch/arm/boot/dts/bcm2837-rpi-3-b-plus.dts``::
351 cec-gpios = <&gpio 6 (GPIO_ACT <<
352 hpd-gpios = <&gpio 23 GPIO_ACT <<
353 v5-gpios = <&gpio 25 GPIO_ACTI <<
354 }; <<
355 342
356 cec@7 { !! 343 cec-gpio@7 {
357 compatible = "cec-gpio"; 344 compatible = "cec-gpio";
358 cec-gpios = <&gpio 7 (GPIO_ACT 345 cec-gpios = <&gpio 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
359 hpd-gpios = <&gpio 12 GPIO_ACT !! 346 hpd-gpios = <&gpio 17 GPIO_ACTIVE_HIGH>;
360 v5-gpios = <&gpio 22 GPIO_ACTI 347 v5-gpios = <&gpio 22 GPIO_ACTIVE_HIGH>;
361 }; 348 };
362 349
363 If you haven't hooked up the HPD and/or 5V lin !! 350 cec-gpio@8 {
364 lines. !! 351 compatible = "cec-gpio";
>> 352 cec-gpios = <&gpio 8 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
>> 353 hpd-gpios = <&gpio 27 GPIO_ACTIVE_HIGH>;
>> 354 v5-gpios = <&gpio 24 GPIO_ACTIVE_HIGH>;
>> 355 };
365 356
366 This dts change will enable two cec GPIO devic 357 This dts change will enable two cec GPIO devices: I typically use one to
367 send/receive CEC commands and the other to mon 358 send/receive CEC commands and the other to monitor. If you monitor using
368 an unconfigured CEC adapter then it will use G 359 an unconfigured CEC adapter then it will use GPIO interrupts which makes
369 monitoring very accurate. 360 monitoring very accurate.
370 361
371 If you just want to monitor traffic, then a si <<
372 The minimum configuration is one HDMI female-f <<
373 and two female-female breadboard wires: one fo <<
374 pin to a ground pin on the Raspberry Pi, and t <<
375 CEC pin to GPIO 6 on the Raspberry Pi. <<
376 <<
377 The documentation on how to use the error inje 362 The documentation on how to use the error injection is here: :ref:`cec_pin_error_inj`.
378 363
379 ``cec-ctl --monitor-pin`` will do low-level CE 364 ``cec-ctl --monitor-pin`` will do low-level CEC bus sniffing and analysis.
380 You can also store the CEC traffic to file usi 365 You can also store the CEC traffic to file using ``--store-pin`` and analyze
381 it later using ``--analyze-pin``. 366 it later using ``--analyze-pin``.
382 367
383 You can also use this as a full-fledged CEC de 368 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 369 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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