Correct Yocto machine for imx8mini EVK using BD71847

[edwardtyrrell]

Hi,

We're developing a new product based on the 8MMINI EVK (MPN: 8MMINILPD4-EVK) and are having a few teething problems mainly finding the correct Yocto build for it. There are two variants of the 8MMINI as far as I can understand, one is the EVK and the other being the EVKB; we're using the what we think is the EVK. The model printed on the plugin imx module is '8MMINILPD4-CPU' and it uses a BD71847 PMIC. There are no dip switches on the imx module unlike the EVKB.

Yocto git is => imx-linux-honister -m imx-5.15.5

Initially we tried DISTRO=fsl-imx-wayland MACHINE=imx8mm-lpddr4-evk but on running up the board (sdcard) we got the following error:

U-Boot SPL 2021.04-lf_v2021.04+gf7b43f8b4c (Mar 01 2022 - 07:31:56 +0000)
Can't find PMIC:PCA9450   <==============================
DDRINFO: start DRAM init
DDRINFO: DRAM rate 3000MTS
DDRINFO:ddrphy calibration done
DDRINFO: ddrmix config done
SEC0: RNG instantiated
Normal Boot
Trying to boot from MMC1
NOTICE: BL31: v2.4(release):lf-5.15.5-1.0.0-0-g05f788b9b
NOTICE: BL31: Built : 05:49:10, Mar 2 2022

Clearly the PMIC was wrong and probably for the EVKB...

Next I tried  DISTRO=fsl-imx-wayland MACHINE=imx8mm-ddr4-evk but after running it up again on sdcard I received another error: 

U-Boot SPL 2021.04-lf_v2021.04+gf7b43f8b4c (Mar 01 2022 - 07:31:56 +0000)
power_bd71837_init
DDRINFO: start DRAM init
DDRINFO: DRAM rate 2400MTS
Training FAILED

Albeit the PMIC part number was slightly wrong (should be BD71847) it passed initialisation. 

So, what is the correct machine type for this EVK? I understand that the imx8mmini UBOOT is different to the imx6/7s that we're used too, is there a feature used by default that we're unaware of? Also as this is the first run there is no need for security at this stage. Any help would be appreciated!

Thanks.
      

[khang_letruong]

Hi @edwardtyrrell ,

Were you running the image on the EVK or on your iMX8M Mini based board ? There's following discussion about similar error : https://community.nxp.com/t5/i-MX-Processors/Can-t-find-PMIC-PCA9450/m-p/1150017

[edwardtyrrell · Accepted solution]

Thanks! Got there in the end. On the board it's printed 'lpddr4' above the memory so I stuck with the imx8mm-lpddr4-evk machine. The main issue regarding boot failures was the image and the SD card I was using did not like each other.. I changed over to eMMC and UUU and the board sprung to life. There is still the issue with the imx8mm-lpddr4-evk machine build thinking that it needs a PCA9450 instead of a BD71847 which is on my version of the imx8mmini, but I'll change that in the device tree. Appreciate your reply.