From aa6169902790c9c027b0123d2b30944501977380 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Mon, 27 Dec 2021 15:09:53 +0000 Subject: [PATCH] docs(allwinner): add SUNXI_SETUP_REGULATORS build option Document the newly introduced SUNXI_SETUP_REGULATORS build option, that allows to disable PMIC regulator setup at build time. Signed-off-by: Andre Przywara Change-Id: Ie5fb0b7220426b67cfffc95df4cabb31a6ec174a --- docs/plat/allwinner.rst | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/docs/plat/allwinner.rst b/docs/plat/allwinner.rst index b6969896a..1bf4f516b 100644 --- a/docs/plat/allwinner.rst +++ b/docs/plat/allwinner.rst @@ -26,6 +26,22 @@ To build for machines with an H616 or H313 SoC: make CROSS_COMPILE=aarch64-linux-gnu- PLAT=sun50i_h616 DEBUG=1 bl31 +Platform-specific build options +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The default build options should generate a working firmware image. There are +some build options that allow to fine-tune the firmware, or to disable support +for optional features. + +- ``SUNXI_SETUP_REGULATORS`` : On SoCs that typically ship with a PMIC + power management controller, BL31 tries to set up all needed power rails, + programming them to their respective voltages. That allows bootloader + software like U-Boot to ignore power control via the PMIC. + This setting defaults to 1. In some situations that enables too many + regulators, or some regulators need to be enabled in a very specific + sequence. To avoid problems with those boards, ``SUNXI_SETUP_REGULATORS`` + can bet set to ``0`` on the build command line, to skip the PMIC setup + entirely. Any bootloader or OS would need to setup the PMIC on its own then. Installation ------------