From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jorge Ramirez-Ortiz, Gmail <jorge.ramirez.ortiz@gmail.com>
Date: Fri, 17 Jan 2020 17:51:04 +0100
Subject: question: mx7ulp - LDO_ENABLED_MODE
In-Reply-To: <CAOMZO5BREwtHueLTzgZ=rsr+odxBVZDtfYf-F_KYi+HqK3pDjg@mail.gmail.com>
References: <20200116203000.GA21781@trex>
 <CAOMZO5BREwtHueLTzgZ=rsr+odxBVZDtfYf-F_KYi+HqK3pDjg@mail.gmail.com>
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On 17/01/20 10:26:11, Fabio Estevam wrote:
> Hi Jorge,
>=20
> On Thu, Jan 16, 2020 at 5:30 PM Jorge Ramirez-Ortiz, Foundries
> <jorge@foundries.io> wrote:
> >
> > Hi Fabio,
> >
> > I am trying to enable LDO in an imx7ulp based board but somehow the
> > board locks up as soon I  write to PMC1_RUN (using the init_ldo_mode
> > sequence).
> >
> > I think it is interesting that bit PMC0_CTRL_PMC1ON is already set so
> > I am wondering if you think it is possible - in your experience- that
> > ROM might have already configured LDO? or was this also the case -
> > this bit already set- when you tested the feature?
> >
> > I also noticed that if I dont execute the init_ldo_mode sequence and
> > just check for the LODEN bit [see snipet below], this is already set
> > which too seems strange.
>=20
> On a i.MX7ULP Embedded Artists board I noticed that LDOEN bit comes
> set after POR too.
>=20
> Should we do something like this to avoid re-initializing the PMC1?
>=20
> --- a/arch/arm/mach-imx/mx7ulp/soc.c
> +++ b/arch/arm/mach-imx/mx7ulp/soc.c
> @@ -122,6 +122,9 @@ static void init_ldo_mode(void)
>  {
>         unsigned int reg;
>=20
> +       if (ldo_mode_is_enabled())
> +               return;
> +
>         /* Set LDOOKDIS */
>         setbits_le32(PMC0_BASE_ADDR + PMC0_CTRL, PMC0_CTRL_LDOOKDIS);

btw was checking the TRM manual (Chapter 28, PMC - page 1172)

[..]
PMC1 power mode[LDOVL] fields don=E2=80=99t necessarily satisfy the operati=
on voltage levels
required by the system. Such operation voltage requirements can be found on=
 i.MX 7ULP
Data Sheet. In this sense, no power transition should be performed before e=
nsuring the
mentioned register fields are matching the required operation voltage level=
s expressed on
the data sheet.

=3D>  0.95V in the ldt_init function, is it in the data sheet?
I just cant find that particular document