arm: mxs: Enable booting of mx28 without battery
Section 4.1.2 of Freescale Application Note AN4199 describes the
configuration required to operate the mx28 from a 5V source without a
battery.
This patch changes the behaviour of the dropout control of the DC-DC
converter (refer to section 11.12.9 of the mx28 Application Processor
Reference Manual - Document Number: MCIMX28RM, Rev 2, 08/2013) to the
following:
- Always use 4P2 Linear Regulator if CONFIG_SYS_MXS_VDD5V_ONLY is defined
- Switch between 4P2 Linear Regulator and Battery, using whichever has
the highest voltage if CONFIG_SYS_MXS_VDD5V_ONLY isnot set (this is
the same as the pre-patch behaviour)
Signed-off-by: Graeme Russ <gruss@tss-engineering.com>
Signed-off-by: Damien Gotfroi <dgotfroi@greenwatch.be>
1 file changed