AM69: Where can I find information about controlling the LDO from PMIC for SD card UHS-I

Daniel Mårtensson

Part Number: AM69

Tool/software:

Hi!

I want to know how the SD card UHS-I can tell the processor to tell the PMIC to change the SD pull-up voltage from 3.3V to 1.8V.

Is this configurable inside the device tree?

2 months ago

+1 Keerthy J 2 months ago

TI__Guru**** 164730 points

Hello,

Yes usually a SoC GPIO is modelled as the regulator to switch between 1.8v to 3.3v. You can look at the sdhci nodes in the k3-j784s4-main.dtsi.

Best Regards,

Keerthy

0 Daniel Mårtensson 2 months ago in reply to Keerthy J

Prodigy 50 points

Thank you. Now I know that this PMIC or GPIO configuration setup for controlling the voltage of the pull-ups for the SD card bus, can be done inside the device tree.

0 Christina Kuruvilla 2 months ago in reply to Daniel Mårtensson

TI__Expert 5960 points

Hello,

The engineer assigned is out for the rest of this week. Thank you for your patience.

Warm regards,

Christina

0 Daniel Mårtensson 2 months ago in reply to Christina Kuruvilla

Prodigy 50 points

Christina Kuruvilla Thank you. I'm waiting for the answer.

+1 Gokul Praveen 2 months ago in reply to Daniel Mårtensson

TI__Genius 12850 points

Hi Daniel,

The vqmmc-supply property contains the pointer to the voltage regulator responsible for voltage switching.

The voltage regulator node given below has the gpios property which contains the GPIO for controlling the voltage switch.

Regards

Gokul

0 Daniel Mårtensson 1 month ago in reply to Gokul Praveen

Prodigy 50 points

Thank you! I'm going to make sure that PMIC can handle the voltage output instead of an GPIO.

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AM69: Where can I find information about controlling the LDO from PMIC for SD card UHS-I