STM32MP157x-EV1 stlinux device tree build

[ThePUP]

Hi. I have generated a full device tree for the EV1 to add I2C5 pins PA11/PA12 for external connector hookup to some of my I2C widgets using STM32CubeMX. I've place the generated .dts file from the kernel/ folder into <linux-source>/arch/arm/boot/dts.

I am now following the Wiki at

https://wiki.st.com/stm32mpu/wiki/How_to_compile_the_device_tree_with_the_Developer_Package

in section 5.3.

. . .

PC $> pushd $WORKDIR/kernel/kernel-sources

(ok)

PC $> make O="$PWD/../build" multi_v7_defconfig

(ok)

PC $> for f in `ls -1 ../../sources/arm-openstlinux_weston-linux-gnueabi/linux-stm32mp-4.19-r0/fragment*.config`; do scripts/kconfig/merge_config.sh -m -r -O $PWD/../build $PWD/../build/.config $f; done

(ok)

PC $> make oldconfig O="$PWD/../build"

(STOP)

PROBLEM. The config script starts asking all of its unknown Y/n | y/N questions to which I have absolutely NO CLUE how to answer.

Please advise regarding how to proceed to get a correct build.

. . .

(not done):

PC $> make stm32mp157c-mydevicetree-mx.dtb LOADADDR=0xC2000040 O="$PWD/../build"

PC $> popd

PC $> ls -l $WORKDIR/kernel/build/arch/arm/boot/dts/stm32mp157c-mydevicetree-mx.dtb

(BTW I have rebuilt and reloaded this kernel more than once onto the EV1 without breaking anything so this is totally new behavior I'm seeing).

Thank you.

[mleo]

Hi @ThePUP​ ,

Please see first https://wiki.st.com/stm32mpu/wiki/I2C_device_tree_configuration

Note that "The STM32CubeMX may not support all the properties described" (chapter 4)  and must be set manually.

If still not working, send your dts file.

Best reagrds,

Milan

[mleo · Accepted solution]

Hi @ThePUP​ 

Regarding the YES question see GitHub readme: https://github.com/STMicroelectronics/meta-st-stm32mp/blob/thud/recipes-kernel/linux/linux-stm32mp/README.HOW_TO.txt chapter 5

 yes '' | make ARCH=arm oldconfig O="$PWD/../build"

Hope this helps

Milan

[ThePUP]

using yes '' | make oldconfig ... does allow the build to continue and complete, even thought I'm not sure ALL the new configurations are really applicable. At any rate, here I am:

1. I have completed building the .dtb from my cube-mx generated .dts.
2. I have loaded and booted the ev1 using my cube-mx compiled .dtb. given so many _extlinux/ options, I simply copied my .dtb to the same name as the default distribution .dtb (stm32mp157c-ev1.dtb).
3. The board boots with no indications differing from the default .dtb boot, so I assume my .dtb is ok at least.

BUT

• I still have no access to anything in linux /dev/i2cx that provides i2cutils to access the port.
• DO I NEED TO ALSO ENABLE SPECIFIC KERNEL DRIVER(s) FOR /dev/i2cx to access I2C5 ?

SO

I am attaching my cube-mx generated .dts source per your previous suggestion.

Thanks for the help (this is my first time through a DTB from scratch).

[ThePUP]

SOLVED (I believe)

I think my previous post was not needed because in fact my cube-mx generated .dts ==> kernel /boot/.dtb process was working in the first place. Thanks again for your suggestions on compilation, those helped.

With the ev1 distribution DTB loaded I get only /dev/i2c0 and /dev/i2c2.

With MY DTB loaded I get and additional /dev/i2c1. I don't know why I didn't see this earlier.

Below is screen dump from terminal showing that I can at least get address ACK from one of my devices now wired to I2C_EXT connector!

Very pleasant result for a Friday ...

root@stm32mp1:~# i2cdetect -y 2

    0 1 2 3 4 5 6 7 8 9 a b c d e f

00:         -- -- -- -- -- -- -- -- -- -- -- -- --

10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

30: -- -- -- UU -- -- -- -- -- -- -- -- -- -- -- --

40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

70: -- -- -- -- -- -- -- --                        

root@stm32mp1:~# i2cdetect -y 0

    0 1 2 3 4 5 6 7 8 9 a b c d e f

00:         -- -- -- -- -- -- -- -- -- -- -- -- --

10: -- -- -- -- -- -- -- -- -- -- -- UU -- -- -- --

20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

30: -- -- -- -- -- -- -- -- -- -- -- -- UU -- -- --

40: -- -- UU -- -- -- -- -- -- -- -- -- -- -- -- --

50: -- -- -- -- -- -- -- -- -- -- -- -- -- UU -- --

60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

70: -- -- -- -- -- -- -- --                        

root@stm32mp1:~# i2cdetect -y 1 <-- /dev/i2c1 in linux (shows up w/ my DTB)

    0 1 2 3 4 5 6 7 8 9 a b c d e f

00:         -- -- -- -- -- -- -- -- -- -- -- -- --

10: -- -- -- -- -- -- -- -- -- 19 -- -- -- -- -- -- <-- this IS my device's address

20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

70: -- -- -- -- -- -- -- --                        

root@stm32mp1:~# ls

Thanks again.

-pete