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arm: mxs: Enable booting of mx28 without battery

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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>
This commit is contained in:
Graeme Russ 2015-01-25 12:07:52 +11:00 committed by Stefano Babic
parent 950eaf6230
commit 7a08603707
1 changed files with 8 additions and 2 deletions
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10
arch/arm/cpu/arm926ejs/mxs/spl_power_init.c
View File

@ -14,6 +14,13 @@
#include "mxs_init.h"
#ifdef CONFIG_SYS_MXS_VDD5V_ONLY
#define DCDC4P2_DROPOUT_CONFIG POWER_DCDC4P2_DROPOUT_CTRL_100MV | \
POWER_DCDC4P2_DROPOUT_CTRL_SRC_4P2
#else
#define DCDC4P2_DROPOUT_CONFIG POWER_DCDC4P2_DROPOUT_CTRL_100MV | \
POWER_DCDC4P2_DROPOUT_CTRL_SRC_SEL
#endif
/**
* mxs_power_clock2xtal() - Switch CPU core clock source to 24MHz XTAL
*
@ -303,8 +310,7 @@ static void mxs_power_init_4p2_params(void)
clrsetbits_le32(&power_regs->hw_power_dcdc4p2,
POWER_DCDC4P2_DROPOUT_CTRL_MASK,
POWER_DCDC4P2_DROPOUT_CTRL_100MV |
POWER_DCDC4P2_DROPOUT_CTRL_SRC_SEL);
DCDC4P2_DROPOUT_CONFIG);
clrsetbits_le32(&power_regs->hw_power_5vctrl,
POWER_5VCTRL_CHARGE_4P2_ILIMIT_MASK,