What's eg vdd_l1_l3-supply in pm8941-regulators?

How can I determine if a regulator is 'regulator-always-on' or 'regulator-boot-on'?

What are the pinctrl things (especially where I can find them in the downstream dts)?

sdhci:
- vqmmc-supply: supply node for IO line power
- vmmc-supply: supply node for card's power
- pinctrl-names: Should contain only one value - "default".
- pinctrl-0: Should specify pin control groups used for this controller.