Best way for enabling SWOUT_ON bit ?

[Eldam]

Hello all,

We made a custom board using stm32mp157 and stpmic. Board is booting, we're using openstlinux, we have prompt and so on.

We'd like to use PMIC_SWIN / PMIC_SWOUT funtionnality (swin=5.2v). On the PMIC datasheet it say that we have to set SWOUT_ON bit from BST_SW_CR reg.

We thinked we could use the dts approach, but we cannot find any clues about it.

My question is:

What is the best (Linux) way to set this bit at each startup?

I've read https://wiki.st.com/stm32mpu/wiki/PMIC_hardware_components but it's a bit confusing for me.

Any clues?

Have a nice day

[Olivier GALLIEN]

Hi @Eldam​ 

Did you have a look to https://wiki.st.com/stm32mpu/wiki/Regulator_overview reference in  https://wiki.st.com/stm32mpu/wiki/PMIC_hardware_components ?

Guess it's best starting point.

PMIC regulator are declared in dts in node &i2c4. ( eg stm32mp157a-dk1.dts)

To switch ON a regulator you can either :

• add property "always-on" in order Linux start it at boot and forever.
• Link this regulator to a consumer driver which will enable it only when needed.

Hope it help

Olivier