[can-next,v2,1/2] CAN: rcar: add gen[12] fallback compatibility strings

Add fallback compatibility string for R-Car Gen 1 and Gen2.

In the case of Renesas R-Car hardware we know that there are generations of
SoCs, e.g. Gen 1 and Gen 2. But beyond that its not clear what the
relationship between IP blocks might be. For example, I believe that
r8a7779 is older than r8a7778 but that doesn't imply that the latter is a
descendant of the former or vice versa.

We can, however, by examining the documentation and behaviour of the
hardware at run-time observe that the current driver implementation appears
to be compatible with the IP blocks on SoCs within a given generation.

For the above reasons and convenience when enabling new SoCs a
per-generation fallback compatibility string scheme being adopted for
drivers for Renesas SoCs.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Rob Herring <robh@kernel.org>

--
v2
* Added Ack from Rob Herring
* Place 'can' at the end of new compatibility strings,
  this is in keeping with current guidelines for compatibility string names.
* Describe use of fallback compatibility strings in conjunction with
  per-SoC compatibility strings
* Enhanced changelog text
---
 Documentation/devicetree/bindings/net/can/rcar_can.txt | 8 +++++++-
 drivers/net/can/rcar_can.c                             | 2 ++
 2 files changed, 9 insertions(+), 1 deletion(-)

On Wed, Feb 24, 2016 at 2:56 AM, Simon Horman
<horms+renesas@verge.net.au> wrote:
> Add fallback compatibility string for R-Car Gen 1 and Gen2.
>
> In the case of Renesas R-Car hardware we know that there are generations of
> SoCs, e.g. Gen 1 and Gen 2. But beyond that its not clear what the
> relationship between IP blocks might be. For example, I believe that
> r8a7779 is older than r8a7778 but that doesn't imply that the latter is a
> descendant of the former or vice versa.
>
> We can, however, by examining the documentation and behaviour of the
> hardware at run-time observe that the current driver implementation appears
> to be compatible with the IP blocks on SoCs within a given generation.
>
> For the above reasons and convenience when enabling new SoCs a
> per-generation fallback compatibility string scheme being adopted for
> drivers for Renesas SoCs.
>
> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
> Acked-by: Rob Herring <robh@kernel.org>

Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds