[PATCH 3/5] arm: mxs: Provide Kconfig option to not enable 4P2 regulator in IMX28 PMU

[sbabic at denx.de]

> 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 at denx.de>
Applied to u-boot-imx, master, thanks !

Best regards,
Stefano Babic

-- 
=====================================================================
DENX Software Engineering GmbH,        Managing Director: Erika Unter  
HRB 165235 Munich,   Office: Kirchenstr.5, 82194 Groebenzell, Germany
Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
=====================================================================