Re: [PATCH v3] irqchip: renesas-intc-irqpin: DT binding for sense bitfield width

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

On Wed, Apr 10, 2013 at 07:23:06AM +0900, Magnus Damm wrote:
> Hi Guennadi,
> 
> On Mon, Apr 8, 2013 at 5:08 PM, Guennadi Liakhovetski
> <g.liakhovetski@gmx.de> wrote:
> > Most Renesas irqpin controllers have 4-bit sense fields, however, some
> > have different widths. This patch adds a DT binding to optionally
> > specify such non-standard values.
> >
> > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
> > ---
> >
> > v3: move the code to a common location, where device configuration
> > parameters are retrieved
> 
> Thanks for rearranging the code, this looks good to me.
> 
> Acked-by: Magnus Damm <damm@opensource.se>

Thanks, queued-up in the renesas-intc-irqpin branch.

> To be clear, I prefer your approach over a per-SoC compatible string.
> 
> In general I think a per-SoC compatible string is nice in theory, but
> I don't think it is correct to use it to describe a change in a IP
> block that just happens to included in the SoC. Instead the version of
> the IP block shall be used with the compatible value. In some cases it
> may not be easy to retrieve such a version.
> 
> The per-SoC compatible string may look good but they come with at
> least two drawbacks. Either
> 1) the driver has to be updated for each new SoC even though the
> device IP the driver is handling hasn't changed which leads to
> 1.1) more need for pointless per-SoC compatible string patches to be
> merged and tracked and back ported
> and
> 1.2) less chance of running a standard distro lacking per-SoC
> compatible string but has actual code for support
> or
> 2) to ship soon the per-SoC DT will use SoC compatible strings
> matching other SoC names which works but is even more confusing.
> 
> For the INTC irqpin case I believe this approach with a single
> property is the best.
> 
> Thanks,
> 
> / magnus
>