[PATCH][v3] dt-bindings: ifc: Update endianness usage

[PATCH][v3] dt-bindings: ifc: Update endianness usage

[Prabhakar Kushwaha]

IFC controller version < 2.0 support IFC register access as
big endian. These controller version also require IFC NOR signals to
be connected in reverse order with NOR flash.

IFC >= 2.0 is other way around.

So updating IFC binding to take care of both using endianness field.

Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha-3arQi8VN3Tc@public.gmane.org>
---
Changes for v2: updated subject
Changes for v3: fixed typo for "big-endian"

 Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt b/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt
index 89427b0..824a2ca 100644
--- a/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt
+++ b/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt
@@ -18,8 +18,10 @@ Properties:
               interrupt (NAND_EVTER_STAT).  If there is only one,
               that interrupt reports both types of event.
 
-- little-endian : If this property is absent, the big-endian mode will
-                  be in use as default for registers.
+- little-endian or big-endian : It represents how IFC registers to be accessed.
+			It also represents connection between controller and
+			NOR flash. If this property is absent, the big-endian
+			mode will be in use as default.
 
 - ranges : Each range corresponds to a single chipselect, and covers
            the entire access window as configured.
-- 
1.9.1

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Re: [PATCH][v3] dt-bindings: ifc: Update endianness usage

[Rob Herring]

On Thu, Nov 30, 2017 at 01:36:36PM +0530, Prabhakar Kushwaha wrote:
> IFC controller version < 2.0 support IFC register access as
> big endian. These controller version also require IFC NOR signals to
> be connected in reverse order with NOR flash.
> 
> IFC >= 2.0 is other way around.
> 
> So updating IFC binding to take care of both using endianness field.
> 
> Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha-3arQi8VN3Tc@public.gmane.org>
> ---
> Changes for v2: updated subject
> Changes for v3: fixed typo for "big-endian"
> 
>  Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt b/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt
> index 89427b0..824a2ca 100644
> --- a/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt
> +++ b/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt
> @@ -18,8 +18,10 @@ Properties:
>                interrupt (NAND_EVTER_STAT).  If there is only one,
>                that interrupt reports both types of event.
>  
> -- little-endian : If this property is absent, the big-endian mode will
> -                  be in use as default for registers.
> +- little-endian or big-endian : It represents how IFC registers to be accessed.
> +			It also represents connection between controller and
> +			NOR flash. If this property is absent, the big-endian
> +			mode will be in use as default.

My question on the prior version remains. I think if you need to handle 
more than just register endianness, that should be done with the 
compatible string.

Rob
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RE: [PATCH][v3] dt-bindings: ifc: Update endianness usage

[Prabhakar Kushwaha]

> -----Original Message-----
> From: Rob Herring [mailto:robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org]
> Sent: Tuesday, December 05, 2017 2:17 AM
> To: Prabhakar Kushwaha <prabhakar.kushwaha-3arQi8VN3Tc@public.gmane.org>
> Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; mark.rutland-5wv7dgnIgG8@public.gmane.org;
> shawnguo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org; linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
> Subject: Re: [PATCH][v3] dt-bindings: ifc: Update endianness usage
> 
> On Thu, Nov 30, 2017 at 01:36:36PM +0530, Prabhakar Kushwaha wrote:
> > IFC controller version < 2.0 support IFC register access as
> > big endian. These controller version also require IFC NOR signals to
> > be connected in reverse order with NOR flash.
> >
> > IFC >= 2.0 is other way around.
> >
> > So updating IFC binding to take care of both using endianness field.
> >
> > Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha-3arQi8VN3Tc@public.gmane.org>
> > ---
> > Changes for v2: updated subject
> > Changes for v3: fixed typo for "big-endian"
> >
> >  Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt
> b/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt
> > index 89427b0..824a2ca 100644
> > --- a/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt
> > +++ b/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt
> > @@ -18,8 +18,10 @@ Properties:
> >                interrupt (NAND_EVTER_STAT).  If there is only one,
> >                that interrupt reports both types of event.
> >
> > -- little-endian : If this property is absent, the big-endian mode will
> > -                  be in use as default for registers.
> > +- little-endian or big-endian : It represents how IFC registers to be accessed.
> > +			It also represents connection between controller and
> > +			NOR flash. If this property is absent, the big-endian
> > +			mode will be in use as default.
> 
> My question on the prior version remains. I think if you need to handle
> more than just register endianness, that should be done with the
> compatible string.
> 

I may not able to use compatible string as this information will also be used it drivers/mtd/maps/physmap_of_core.c other than drivers/memory/fsl_ifc.c.
I am trying to avoid controller specific details in generic file. 

This is the reason endianness property is being used. 

--prabhakar




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RE: [PATCH][v3] dt-bindings: ifc: Update endianness usage

[Prabhakar Kushwaha]

Hi Rob,

> -----Original Message-----
> From: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org [mailto:devicetree-
> owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org] On Behalf Of Prabhakar Kushwaha
> Sent: Tuesday, December 05, 2017 2:45 PM
> To: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; mark.rutland-5wv7dgnIgG8@public.gmane.org;
> shawnguo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org; linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
> Subject: RE: [PATCH][v3] dt-bindings: ifc: Update endianness usage
> 
> 
> > -----Original Message-----
> > From: Rob Herring [mailto:robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org]
> > Sent: Tuesday, December 05, 2017 2:17 AM
> > To: Prabhakar Kushwaha <prabhakar.kushwaha-3arQi8VN3Tc@public.gmane.org>
> > Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; mark.rutland-5wv7dgnIgG8@public.gmane.org;
> > shawnguo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org; linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
> > Subject: Re: [PATCH][v3] dt-bindings: ifc: Update endianness usage
> >
> > On Thu, Nov 30, 2017 at 01:36:36PM +0530, Prabhakar Kushwaha wrote:
> > > IFC controller version < 2.0 support IFC register access as
> > > big endian. These controller version also require IFC NOR signals to
> > > be connected in reverse order with NOR flash.
> > >
> > > IFC >= 2.0 is other way around.
> > >
> > > So updating IFC binding to take care of both using endianness field.
> > >
> > > Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha-3arQi8VN3Tc@public.gmane.org>
> > > ---
> > > Changes for v2: updated subject
> > > Changes for v3: fixed typo for "big-endian"
> > >
> > >  Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt | 6
> ++++--
> > >  1 file changed, 4 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/Documentation/devicetree/bindings/memory-
> controllers/fsl/ifc.txt
> > b/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt
> > > index 89427b0..824a2ca 100644
> > > --- a/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt
> > > +++ b/Documentation/devicetree/bindings/memory-controllers/fsl/ifc.txt
> > > @@ -18,8 +18,10 @@ Properties:
> > >                interrupt (NAND_EVTER_STAT).  If there is only one,
> > >                that interrupt reports both types of event.
> > >
> > > -- little-endian : If this property is absent, the big-endian mode will
> > > -                  be in use as default for registers.
> > > +- little-endian or big-endian : It represents how IFC registers to be accessed.
> > > +			It also represents connection between controller and
> > > +			NOR flash. If this property is absent, the big-endian
> > > +			mode will be in use as default.
> >
> > My question on the prior version remains. I think if you need to handle
> > more than just register endianness, that should be done with the
> > compatible string.
> >
> 
> I may not able to use compatible string as this information will also be used it
> drivers/mtd/maps/physmap_of_core.c other than drivers/memory/fsl_ifc.c.
> I am trying to avoid controller specific details in generic file.
> 
> This is the reason endianness property is being used.
> 

Please let me know if I am not able to address your review comment

--prabhakar

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