Re: [PATCH v2 1/2] watchdog: Add Cadence WDT driver

[Mark Rutland <mark.rutland@arm.com>]

On Mon, Jun 02, 2014 at 07:25:16AM +0100, Michal Simek wrote:
> On 05/29/2014 03:19 PM, Mark Rutland wrote:
> > On Thu, May 29, 2014 at 10:43:05AM +0100, Michal Simek wrote:
> >> Hi Mark,
> >>
> >>>> +static struct of_device_id cdns_wdt_of_match[] = {
> >>>> +       { .compatible = "xlnx,zynq-wdt-r1p2", },
> >>>> +       { .compatible = "cdns,wdt-r1p2", },
> >>>
> >>> If these can currently be handled identically, why not just have
> >>> "cdns,wdt-r1p2" in the driver and in your dts have:
> >>>
> >>> compatible = "xlnx,zynq-wdt-r1p2", "cdns,wdt-r1p2";
> >>>
> >>> If we need to distinguish the two for some reason later we can always
> >>> add the "xlnx,zynq-wdt-r1p2" string to the driver.
> >>
> >> I would prefer to have 2 compatible strings just because
> >> of that we don't know what is different compare to origin cadence
> >> version. We have done the same for spi-cadence.c that's why
> >> it shouldn't be any problem to keep it as is.
> >> Having zynq compatible property here and using it give us option
> >> that if another SoC vendor come with new configuration or clean
> >> cadence one we can simple handle it without changing compatible
> >> property for us.
> > 
> > Sure, we can have two documented strings. But as I mention for the
> > moment the driver only needs to support the one string so long as a
> > given dts has both. Then we can later distinguish the zynq variant (or
> > any other) as necessary.
> 
> ok then. Let's use just "xlnx,zynq-wdt-r1p2" compatible string here
> and remove "cdns,wdt-r1p2"

That if anything seems backwards -- the driver should jsut take the most
general string for now: "cdns,wdt-r1p2", while the dtb will have both:

compatible = "xlnx,zynq-wdt-r1p2", "cdns,wdt-r1p2";

The driver can later disintguish "xlnx,zynq-wdt-r1p2" specially if
necessary.

Cheers,
Mark.