On Tue, Sep 15, 2020 at 9:40 AM Pavel Yermolenko <[email protected]> wrote: > > Well, but where this default specified ? > I mean on Power On how BBB "knows" that P.9.31 is reserved for audio ? > This default meaning is specified somewhere in device tree, isn't it ?
For the BBB, the default image has eMMC, HDMI with Audio, and ADC enabled.. debian@bbb-pwr01-ser09:~$ sudo /opt/scripts/tools/version.sh | grep UBOOT UBOOT: Booted Device-Tree:[am335x-boneblack-uboot-univ.dts] UBOOT: Loaded Overlay:[AM335X-PRU-RPROC-4-14-TI-00A0] UBOOT: Loaded Overlay:[BB-ADC-00A0] UBOOT: Loaded Overlay:[BB-BONE-eMMC1-01-00A0] UBOOT: Loaded Overlay:[BB-HDMI-TDA998x-00A0] The main *.dts file loaded (but compiled) is: am335x-boneblack-uboot-univ.dts With 4 overlays: AM335X-PRU-RPROC-4-14-TI-00A0.dtbo -> provides pru BB-ADC-00A0.dtbo -> provides ADC BB-BONE-eMMC1-01-00A0.dtbo -> provides eMMC BB-HDMI-TDA998x-00A0.dtbo -> provinces HDMI with Audio.. With the out - of box image, use this to disable those overlays: https://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Disable_on-board_devices On the mainline kernel, am335x-boneblack.dts has all these enabled by default. We allow users to disable them to grab the pins for other features. Regards, -- Robert Nelson https://rcn-ee.com/ -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAOCHtYjZX_mSEbFrtEmTequYnbt8K7Bv9Dyk5dO6sCW9za1h7w%40mail.gmail.com.
