Problems with internal ADC in STM32MP1

[aliberal@arroweurope.com]

Hi,

one of my customers has designed a product based in the OSD32MP15x and is working with first prototypes based in the OSD32MP157C-512M-BAA ES (Engineering device). Customer is able to boot the Linux in its prototype but the internal ADC driver is not shown under /sys/bus/iio/devices/.

The device tree looks ok and if customer test it in the ST eval board the ADC driver appears under /sys/bus/iio/devices

I attach you the boot from the customer where you can see some error messages related to the ADC:

CPU: STM32MP157C?? Rev.B
Model: STMicroelectronics STM32MP157C-DK2 Discovery Board
Board: stm32mp1 in trusted mode (st,stm32mp157c-dk2)
DRAM: 512 MiB
Clocks:
– MPU : 650 MHz
– MCU : 208.878 MHz
– AXI : 266.500 MHz
– PER : 24 MHz
– DDR : 533 MHz
Failed to enable vreg: -110
board_check_usb_power: single shot failed for adc@0[18]!
NAND: 0 MiB
MMC: STM32 SDMMC2: 0, STM32 SDMMC2: 1
Loading Environment from EXT4… OK
In: serial
Out: serial
Err: serial

It looks that there is an error related to the Vreg of the ADC. Pls could you help so that my customer can solve the problem and enable the ADC?

Thanks
Alberto

[Neeraj Dantu]

Alberto,

How is the customer powering the VREF pin? This board boot(presumably using starter image for Discovery Kit – 2(DK-2)) assumes that they have the same configuration as DK-2. If they are powering VREF buffer externally, while also turning it on in the device tree could cause it to fault resulting in failure of ADC subsystem to come up.

 

See https://wiki.st.com/stm32mpu/wiki/ADC_device_tree_configuration for info on configuration of ADC according to hardware.

Best,

Neeraj

 

[aliberal@arroweurope.com]

Thanks Neeraj! The problem has been solved thanks to your indication!
Best Regards
Alberto

[Author]

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