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Subject: RE: [v3,3/3] Documentation: dt: binding: fsl: Add
 'fsl,ippdexpcr-alt-addr' property
Thread-Topic: [v3,3/3] Documentation: dt: binding: fsl: Add
 'fsl,ippdexpcr-alt-addr' property
Thread-Index: AQHVcoOnab7d5ysBNkWsXmY0PrfSuKc6/L+AgAC3JZA=
Date:   Wed, 25 Sep 2019 03:13:07 +0000
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> >
> > The 'fsl,ippdexpcr-alt-addr' property is used to handle an errata
> > A-008646 on LS1021A
> >
> > Signed-off-by: Biwen Li <biwen.li@nxp.com>
> > ---
> > Change in v3:
> > 	- rename property name
> > 	  fsl,rcpm-scfg -> fsl,ippdexpcr-alt-addr
> >
> > Change in v2:
> > 	- update desc of the property 'fsl,rcpm-scfg'
> >
> >  Documentation/devicetree/bindings/soc/fsl/rcpm.txt | 14
> > ++++++++++++++
> >  1 file changed, 14 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/soc/fsl/rcpm.txt
> > b/Documentation/devicetree/bindings/soc/fsl/rcpm.txt
> > index 5a33619d881d..157dcf6da17c 100644
> > --- a/Documentation/devicetree/bindings/soc/fsl/rcpm.txt
> > +++ b/Documentation/devicetree/bindings/soc/fsl/rcpm.txt
> > @@ -34,6 +34,11 @@ Chassis Version		Example Chips
> >  Optional properties:
> >   - little-endian : RCPM register block is Little Endian. Without it RC=
PM
> >     will be Big Endian (default case).
> > + - fsl,ippdexpcr-alt-addr : Must add the property for SoC LS1021A,
>=20
> You probably should mention this is related to a hardware issue on LS1021=
a
> and only needed on LS1021a.
Okay, got it, thanks, I will add this in v4.
>=20
> > +   Must include n + 1 entries (n =3D #fsl,rcpm-wakeup-cells, such as:
> > +   #fsl,rcpm-wakeup-cells equal to 2, then must include 2 + 1 entries)=
.
>=20
> #fsl,rcpm-wakeup-cells is the number of IPPDEXPCR registers on an SoC.
> However you are defining an offset to scfg registers here.  Why these two
> are related?  The length here should actually be related to the #address-=
cells
> of the soc/.  But since this is only needed for LS1021, you can just make=
 it 3.
I need set the value of IPPDEXPCR resgiters from ftm_alarm0 device node(fsl=
,rcpm-wakeup =3D <&rcpm 0x0 0x20000000>;
0x0 is a value for IPPDEXPCR0, 0x20000000 is a value for IPPDEXPCR1).
But because of the hardware issue on LS1021A, I need store the value of IPP=
DEXPCR registers
to an alt address. So I defining an offset to scfg registers, then RCPM dri=
ver get an abosolute address from offset,
 RCPM driver write the value of IPPDEXPCR registers to these abosolute addr=
esses(backup the value of IPPDEXPCR registers).
>=20
> > +   The first entry must be a link to the SCFG device node.
> > +   The non-first entry must be offset of registers of SCFG.
> >
> >  Example:
> >  The RCPM node for T4240:
> > @@ -43,6 +48,15 @@ The RCPM node for T4240:
> >  		#fsl,rcpm-wakeup-cells =3D <2>;
> >  	};
> >
> > +The RCPM node for LS1021A:
> > +	rcpm: rcpm@1ee2140 {
> > +		compatible =3D "fsl,ls1021a-rcpm", "fsl,qoriq-rcpm-2.1+";
> > +		reg =3D <0x0 0x1ee2140 0x0 0x8>;
> > +		#fsl,rcpm-wakeup-cells =3D <2>;
> > +		fsl,ippdexpcr-alt-addr =3D <&scfg 0x0 0x51c>; /*
> > SCFG_SPARECR8 */
> > +	};
> > +
> > +
> >  * Freescale RCPM Wakeup Source Device Tree Bindings
> >  -------------------------------------------
> >  Required fsl,rcpm-wakeup property should be added to a device node if
> > the device
> > --
> > 2.17.1