Re: [RFC PATCH net-next v2 2/3] sh_eth: add support RMIIMODE register

[Simon Horman <horms@verge.net.au>]

On Thu, Jun 06, 2013 at 12:43:55AM +0400, Sergei Shtylyov wrote:
> Hello.
> 
> On 05/15/2013 04:51 AM, Simon Horman wrote:
> 
> >>>This change is motivated by the lager board which uses the r8a7790 SoC,
> >>>an R-Car SoC. For this board setting the RMIIMODE register is necessary.
> >>>This patch assumes this is valid for all R-Car SoCs.
> >>    No, RMIIMODE register is not documented on R8A7778/9 SoCs and
> >>this location is described as reserved. How's it called in R8A7790
> >>manual, CXR15?
> >It appears to be undocumented in the R8A7790 I have.
> 
>     Of the manuals I have now this register is only documented in
> R-Car H2 user's manual 0.50,
> 
> >Empirically it seems necessary for the lager/R8A7790.
> 
>    The manual confirms that.
> 
> >To be honest I am entirely unsure of its relevance to other SoCs.
> >
> >I wonder if a better approach would be to add a flag to platform
> >data rather than struct sh_eth_cpu_data. This would allow the register
> >to only be accessed on boards where it is known to be useful.
> 
>    No, this doesn't depend on the board, judging on the H2 manual.
> You just must write it to 1 on R-Car H2 in order for Ether to operate.

What is your preferred way to add support for this to the driver?