[1/3][PATCH][v2] Device Tree bindings for Freescale TDM controller

[sandeep at freescale.com]

Hi Scott,

Thanks for your comments. Reply inline.

Regards
Sandeep

> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Friday, April 03, 2015 6:45 AM
> To: Singh Sandeep-B37400
> Cc: linuxppc-dev at ozlabs.org
> Subject: Re: [1/3][PATCH][v2] Device Tree bindings for Freescale TDM controller
> 
> On Thu, 2015-04-02 at 16:17 +0530, sandeep at freescale.com wrote:
> > From: Sandeep Singh <sandeep at freescale.com>
> >
> > This controller is available on many Freescale SOCs like MPC8315,
> > P1020, P1010,
> > P1022 and P1024
> >
> > Signed-off-by: Sandeep Singh <Sandeep at freescale.com>
> > Signed-off-by: Poonam Aggrwal <poonam.aggrwal at freescale.com>
> > ---
> >  Documentation/devicetree/bindings/tdm/fsl-tdm.txt |   65
> +++++++++++++++++++++
> >  1 files changed, 65 insertions(+), 0 deletions(-)  create mode 100644
> > Documentation/devicetree/bindings/tdm/fsl-tdm.txt
> 
> Add devicetree at vger.kernel.org to CC for device tree patches.
> 
> 
> > diff --git a/Documentation/devicetree/bindings/tdm/fsl-tdm.txt
> > b/Documentation/devicetree/bindings/tdm/fsl-tdm.txt
> > new file mode 100644
> > index 0000000..1258b89
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/tdm/fsl-tdm.txt
> > @@ -0,0 +1,65 @@
> >
> +=================================================================
> ====
> > +TDM Device Tree Binding
> > +Copyright (C) 2012 Freescale Semiconductor Inc.
> > +
> > +NOTE: The bindings described in this document are preliminary and
> > +subject to change.
> 
> Get rid of this note.  Bindings are expected to be stable ABI once merged.
> 
> >
> +=================================================================
> ====
> > +TDM (Time Division Multiplexing)
> > +
> > +DESCRIPTION
> > +
> > +The TDM is full duplex serial port designed to allow various devices
> > +including digital signal processors (DSPs) to communicate with a
> > +variety of serial devices including industry standard framers, codecs, other
> DSPs and microprocessors.
> > +
> > +The below properties describe the device tree bindings for Freescale
> > +TDM controller.
> > +This TDM controller is available on various Freescale Processors like
> > +MPC8313, P1020, P1022 and P1010.
> > +
> > +PROPERTIES
> > +
> > +  - compatible
> > +      Usage: required
> > +      Value type: <string>
> > +      Definition: Should contain "fsl,tdm1.0".
> 
> What does 1.0 refer to?  Is the TDM block identical on all the chips that currently
> have it?  Is this a real version number scheme (public or
> otherwise) or something made up for software?
[Sandeep] Starlite TDM block is identical on all the chips. This is a software only version.
> 
> > +  - reg
> > +      Usage: required
> > +      Definition: A standard property. The first reg specifier describes the
> > +          TDM registers, and the second describes the TDM DMAC registers.
> > +
> > +  - clock-frequency
> > +      Usage: optional
> > +      Value type: <u32 or u64>
> > +      Definition: The frequency at which the TDM block is operating.
> 
> It'd be nice if new bindings used clock nodes rather than relying on U-Boot fixups.
[Sandeep] This field is not currently used, but is planned to be used in future.
> 
> > +  - interrupts
> > +      Usage: required
> > +      Definition: Definition: Two interrupt specifiers.  The first is TDM
> > +          error, and the second is TDM EMAC.
> > +
> > +  - phy-handle
> > +      Usage: optional
> > +      Value type: <phandle>
> > +      Definition: Phandle of the line controller node or framer node eg. SLIC,
> > +          E1/T1 etc.
> > +
> > +  - fsl,max-time-slots
> > +      Usage: required
> > +      Value type: <u32>
> > +      Definition: Maximum number of 8-bit time slots in one TDM frame.
> > +          This is the maximum number which TDM hardware supports.
> > +
> > +EXAMPLE
> > +
> > +	tdm at 16000 {
> > +		compatible = "fsl,tdm1.0";
> > +		reg = <0x16000 0x200 0x2c000 0x2000>;
> > +		clock-frequency = <0>;
> > +		interrupts = <16 8 62 8>;
> > +		phy-handle = <&zarlink1>;
> > +		fsl,max-time-slots = <128>;
> > +	};
> 
> The example refers to a "zarlink1" node but it is not present.  What does a "line
> controller or framer node" look like?
[Sandeep] phy-handle again is currently not being used. Added for future use.
> 
> -Scott
>