[U-Boot] [PATCH 1/2] ARM: mxs: Enable DCDC converter for battery boot

[Marek Vasut]

Dear Fabio Estevam,

> Hi Marek,
> 
> On Mon, Oct 28, 2013 at 9:29 AM, Marek Vasut <marex at denx.de> wrote:
> > In case the board detected sufficient voltage for battery boot,
> > make sure the DCDC converter is ON and the board is not running
> > only from linregs, otherwise an instability will be observed.
> > 
> > Signed-off-by: Marek Vasut <marex at denx.de>
> > Cc: Stefano Babic <sbabic at denx.de>
> > Cc: Fabio Estevam <fabio.estevam at freescale.com>
> > ---
> > 
> >  arch/arm/cpu/arm926ejs/mxs/spl_power_init.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c
> > b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c index 8ea45be..d25019a
> > 100644
> > --- a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c
> > +++ b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c
> > @@ -654,6 +654,8 @@ static void mxs_batt_boot(void)
> > 
> >         clrsetbits_le32(&power_regs->hw_power_5vctrl,
> >         
> >                 POWER_5VCTRL_CHARGE_4P2_ILIMIT_MASK,
> >                 0x8 << POWER_5VCTRL_CHARGE_4P2_ILIMIT_OFFSET);
> > 
> > +
> > +       mxs_power_enable_4p2();
> 
> Shouldn't this be conditional?
> 
> #if defined CONFIG_MXS_ENABLE_4P2
> mxs_power_enable_4p2();
> #endif
> 
> Then the boards that need this power supply enable
> CONFIG_MXS_ENABLE_4P2 in its config file.

No, we want to start the DCDC converter unconditionally when running on battery 
power to increase efficiency.

Best regards,
Marek Vasut