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arm: mxs: Provide Kconfig option to not enable 4P2 regulator in IMX28 PMU

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The IMX28 PMU (Power Management Unit) has a dedicated Linear Regulator
to produce (by default) 4.2V output - available outside the chip as
VDD_4P2.

When system is supposed to not use VDD5V as a main power source - instead
the DCDC_BATT is used; it is safe to disable this regulator.

As the in-PMU DCDC switching regulator (from which DCDC_VDDA, DCDC_VDDIO
and DCDC_VDDD are generated) can be driven from DCDC_BATT or output
of this 4P2 regulator - by disabling the latter the use of the DCDC_BATT
is forced.

To be more specific - according to NXP's AN4199 the DCDC_BATT source is
preferred (over VDD5V), as more efficient and stable source for
industrial applications.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
This commit is contained in:
Lukasz Majewski 2023-05-09 16:32:41 +02:00 committed by Stefano Babic
parent 249a3cc1af
commit 79230640cb
2 changed files with 9 additions and 1 deletions
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3
arch/arm/cpu/arm926ejs/mxs/spl_power_init.c
View File

@ -763,7 +763,8 @@ static void mxs_batt_boot(void)
&power_regs->hw_power_5vctrl_set); &power_regs->hw_power_5vctrl_set);
} }
mxs_power_enable_4p2(); if (CONFIG_IS_ENABLED(MXS_PMU_ENABLE_4P2_LINEAR_REGULATOR))
mxs_power_enable_4p2();
} }
/** /**

7
arch/arm/mach-imx/mxs/Kconfig
View File

@ -63,6 +63,13 @@ config SPL_MXS_PMU_DISABLE_BATT_CHARGE
bool "Disable Battery Charging in MX28 PMU" bool "Disable Battery Charging in MX28 PMU"
default n default n
config SPL_MXS_PMU_ENABLE_4P2_LINEAR_REGULATOR
bool "Enable the 4P2 linear regulator in MX28 PMU"
default y
help
This option enables the 4P2 linear regulator (derived
from VDD5V) - so the VDD4P2 power source is operational.
source "board/freescale/mx28evk/Kconfig" source "board/freescale/mx28evk/Kconfig"
source "board/liebherr/xea/Kconfig" source "board/liebherr/xea/Kconfig"