Message ID | 20230509143243.1523791-3-lukma@denx.de |
---|---|
State | Accepted |
Commit | 79230640cb4fb780e2be9bb9a47b31976b18cac4 |
Delegated to: | Stefano Babic |
Headers | show |
Series | [1/5] arm: mxs: Provide Kconfig option to to not use VDD5V as IMX28 PMU source | expand |
> 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> Applied to u-boot-imx, master, thanks ! Best regards, Stefano Babic
diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c index 7c584db27c..24f61b4b56 100644 --- a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c +++ b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c @@ -763,7 +763,8 @@ static void mxs_batt_boot(void) &power_regs->hw_power_5vctrl_set); } - mxs_power_enable_4p2(); + if (CONFIG_IS_ENABLED(MXS_PMU_ENABLE_4P2_LINEAR_REGULATOR)) + mxs_power_enable_4p2(); } /** diff --git a/arch/arm/mach-imx/mxs/Kconfig b/arch/arm/mach-imx/mxs/Kconfig index f5e45ae846..5cffc26103 100644 --- a/arch/arm/mach-imx/mxs/Kconfig +++ b/arch/arm/mach-imx/mxs/Kconfig @@ -63,6 +63,13 @@ config SPL_MXS_PMU_DISABLE_BATT_CHARGE bool "Disable Battery Charging in MX28 PMU" 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/liebherr/xea/Kconfig"
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> --- arch/arm/cpu/arm926ejs/mxs/spl_power_init.c | 3 ++- arch/arm/mach-imx/mxs/Kconfig | 7 +++++++ 2 files changed, 9 insertions(+), 1 deletion(-)