Dennis,
Thanks for your feedback. Regarding your comment about whether I had
compiled the dts source file, I used the mechanism provided by buildroot:
“make linux-rebuild” and then “make”. Since I’m not and expert in modifying
dts files and I made some mistakes, I had to correct them in that file. So,
I’m sure am335x-boneblack.dtb file used by uboot contains the modifications
I made to dts.
As for the list of commands I launched in order to pinpoint the problem, I
might agree with you that it is meaningless. Which commands would you try
in order to identify the problem? My understanding is that spidev_test
program is useless unless you have those /dev/spi* devices created
beforehand.
I'm beginning to think that the cause of the problem is in the kernel
configuration rather than in the dts files. Specifically in spidev. The
command "lsmod" reports no modules loaded when bootstrapping the BBB using
the images generated by buildroot. In case of using Debian images provided
"lsmod" reports a list of modules, one of them being "spidev".
Ideas?
Thanks again,
Joan Salvat
El dilluns, 25 novembre de 2019 0:20:11 UTC+1, Dennis Bieber va escriure:
>
> {blast -- forgot to use email reply, so I'm going to be dinged by the
> autoresponder again <G>}
>
>
> >Hi,
> >
> >I'm trying to use spi1 on a BeagleBone Black. Since I don't know how to
> >deal with cape manager and to load dtbo files I decided to modify
> >am335x-boneblack.dts file. DTS file
> ><https://www.dropbox.com/s/s4vdtpebwo56fxu/am335x-boneblack.dts?dl=0>
> Also
> >I've learnt that I needed to deactivate HDMI and MCASP0. Despite so
> >/dev/spi1 device is not created.
> >
>
> You haven't mentioned compiling your modified DTS file... Really,
> if
> you can understand the device tree source enough to modify it, compile it,
> and place it into the correct location for subsequent boots, playing with
> /boot/uEnv.txt should be trivial...
>
>
> >The results of the commands below would indicate that the dts file is
> >properly modified but it seems there is still missing something. I've
> used
> >buildroot (LTS version) configured as "beaglebone_defconfig"
> >
> >[root@buildroot]# find / -name spi1
> >/sys/devices/platform/ocp/481a0000.spi/spi_master/spi1
> >/sys/class/spi_master/spi1
> >/sys/firmware/devicetree/base/__symbols__/spi1
> >/sys/firmware/devicetree/base/aliases/spi1
> >
>
> Even the STOCK LXQT image (I have done nothing with device trees)
>
> https://debian.beagleboard.org/images/bone-debian-9.9-lxqt-armhf-2019-08-03-4gb.img.xz
>
> shows
>
> debian@beaglebone:~$ sudo find / -iname "spi1"
> [sudo] password for debian:
> /sys/devices/platform/ocp/48030000.spi/spi_master/spi1
> /sys/class/spi_master/spi1
> /sys/firmware/devicetree/base/__symbols__/spi1
> /sys/firmware/devicetree/base/aliases/spi1
> debian@beaglebone:~$
>
> so your above check is likely meaningless. The following rambling is being
> done with the IoT image (I'd thought it might have already disabled HDMI,
> but nooooo....)
>
> https://elinux.org/BeagleBone_Black_Enable_SPIDEV appears to be quite
> out-of-date, since everything they mention finding via "ls" is shown
> without ever changing a device tree. And especially the
> echo BB-SPI1-01 > /sys/devices/bone_capemgr.*/slots
> as there is no capemgr directory in /sys/devices anymore. There is one in
> /sys/firmware/devicetree/base
>
> https://groups.google.com/forum/#!topic/beagleboard/RShjePl0noY is more
> up-to-date with current images
>
> >[root@buildroot]# find / -name spidev@1
> >/sys/firmware/devicetree/base/ocp/spi@481a0000/spidev@1
>
> No such critter... Actually, no .../spidev@anything (there ARE
> .../channel@0 and .../channel@1 )
>
> And to confuse matters it appears that
> OVERLAY /dev
> BB-SPIDEV0-00A0 /spidev1.x
> BB-SPIDEV1-00A0 /spidev2.x
>
> Disabling all the system overlays and adding the SPIDEV overlays
> (difference in /boot/uEnv.txt shown next)
>
> debian@beaglebone:~$ diff /boot/uEnv.txt mod_uEnv.txt
> 19c19,20
> < #uboot_overlay_addr4=/lib/firmware/<file4>.dtbo
> ---
> > uboot_overlay_addr4=/lib/firmware/BB-SPIDEV1-00A0.dtbo
> > uboot_overlay_addr5=/lib/firmware/BB-SPIDEV0-00A0.dtbo
> 28,32c29,33
> < #disable_uboot_overlay_emmc=1
> < #disable_uboot_overlay_video=1
> < #disable_uboot_overlay_audio=1
> < #disable_uboot_overlay_wireless=1
> < #disable_uboot_overlay_adc=1
> ---
> > disable_uboot_overlay_emmc=1
> > disable_uboot_overlay_video=1
> > disable_uboot_overlay_audio=1
> > disable_uboot_overlay_wireless=1
> > disable_uboot_overlay_adc=1
> debian@beaglebone:~$
>
> seems to work (once I figured out I had /spidev1.x jumpered wrong for the
> test program)
>
> Note: other than the "disable" lines above, the spi overlays were
> not
> mandatory -- config-pin is sufficient!
>
> #/dev/spidev1.x
> debian@beaglebone:~$ sudo config-pin p9_21 spi
> debian@beaglebone:~$ sudo config-pin p9_18 spi
> debian@beaglebone:~$ sudo config-pin p9_17 spi_cs
> debian@beaglebone:~$ sudo config-pin p9_22 spi_sclk
> #/dev/spidev2.x
> debian@beaglebone:~$ sudo config-pin p9_30 spi
> debian@beaglebone:~$ sudo config-pin p9_29 spi
> debian@beaglebone:~$ sudo config-pin p9_28 spi_cs
> debian@beaglebone:~$ sudo config-pin p9_31 spi_sclk
> #with jumper p9_21 <> p9_18 and p9_30 <> p9_29
> #even without having the book, you can get/build the test program
> # http://exploringbeaglebone.com/source/
> debian@beaglebone:~$ ./exploringBB/chp08/spi/spidev_test/spidev_test -D
> /dev/spidev2.0
> spi mode: 0
> bits per word: 8
> max speed: 500000 Hz (500 KHz)
>
> FF FF FF FF FF FF
> 40 00 00 00 00 95
> FF FF FF FF FF FF
> FF FF FF FF FF FF
> FF FF FF FF FF FF
> DE AD BE EF BA AD
> F0 0D
> debian@beaglebone:~$ ./exploringBB/chp08/spi/spidev_test/spidev_test -D
> /dev/spidev1.0
> spi mode: 0
> bits per word: 8
> max speed: 500000 Hz (500 KHz)
>
> FF FF FF FF FF FF
> 40 00 00 00 00 95
> FF FF FF FF FF FF
> FF FF FF FF FF FF
> FF FF FF FF FF FF
> DE AD BE EF BA AD
> F0 0D
> debian@beaglebone:~$
>
> HMMM! looks like "sudo" wasn't needed anymore, either.
>
> SEQUENCE to enable both SPI devices!:
>
> EDIT /boot/uEnv.txt
> CHANGE
> #disable_uboot_overlay_video=1
> TO
> disable_uboot_overlay_video=1
> REBOOT
> EXECUTE... (I put them into a shell script as I was doing so many reboots)
> debian@beaglebone:~$ cat setspi.sh
> #!/usr/bin/env bash
> #/dev/spidev1.x aka overlay spidev0
> config-pin p9_21 spi
> config-pin p9_18 spi
> config-pin p9_17 spi_cs
> config-pin p9_22 spi_sclk
> #/dev/spidev2.x aka overlay spidev1 Conflicts with HDMI overlay
> config-pin p9_30 spi
> config-pin p9_29 spi
> config-pin p9_28 spi_cs
> config-pin p9_31 spi_sclk
>
> (if you do not disable video, the above will result in errors for pins 28,
> 29, and 31, used by HDMI)
>
> debian@beaglebone:~$ ./setspi.sh
> P9_29 pinmux file not found!
> sudo: no askpass program specified, try setting SUDO_ASKPASS
> Cannot write pinmux file: /sys/devices/platform/ocp/ocp*P9_29_pinmux/state
> P9_28 pinmux file not found!
> sudo: no askpass program specified, try setting SUDO_ASKPASS
> Cannot write pinmux file: /sys/devices/platform/ocp/ocp*P9_28_pinmux/state
> P9_31 pinmux file not found!
> sudo: no askpass program specified, try setting SUDO_ASKPASS
> Cannot write pinmux file: /sys/devices/platform/ocp/ocp*P9_31_pinmux/state
>
>
> Putting the SPIDEV overlays into /boot/uEnv.txt will result in
> locking
> the pins to SPI, removing them from config-pin set-up.
>
> --
> Dennis L Bieber
>
>
--
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