On Wed, Sep 19, 2018 at 09:48:53AM +0200, Geert Uytterhoeven wrote:
> On Fri, Sep 14, 2018 at 10:17 PM Sergei Shtylyov
> <sergei.shtylyov@xxxxxxxxxxxxxxxxxx> wrote:
> > On 09/11/2018 09:26 PM, Sergei Shtylyov wrote:
> >
> > >>> Document the R-Car V3{M|H} (R8A779{7|8}0) SoC in the Renesas TMU bindings;
> > >>> the TMU hardware in those is the Renesas standard 3-channel timer unit.
> > >>>
> > >>> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
> > >>
> > >> Thanks for your patch!
> > >>
> > >> Not all channels seem to be identical, but the driver just matches against
> > >> the "renesas,tmu" fallback?
> > >
> > > The only difference between TMUs is the input capture capability on the 3rd
> > > channel in each TMU -- that includes TCPR register and extra interrupt output
> >
> > Not only that, the TMUs having the input capture also can use external clock
> > as they have the TCLK<n> signal.
> >
> > > TICPI<n> (perhaps has to do with 4th TMU IRQ?).
> >
> > They don't, most probably.
> >
> > > The driver is blissfully unaware
> > > of this extra capability. :-)
> >
> > Perhaps we should describe a "renesas,tmu-ext-clk" for the TMUs having an external
> > clock? Will this make you happy?
> >
> > >> In addition, the V3H TMU seems to differ from the TMU in other R-Car Gen3
> > >> variants?
> > >
> > > Yes, but they only differ in the number of channels capable of input capture.
> >
> > ... and having external clock.
> >
> > >> How is this handled?
> > >
> > > Nohow. And I'm not sure we should care about this difference...
> >
> > At this point, the driver only uses internal clock... we can document the external
> > clock for the compatible value I've just suggested... Will that make you happy? :-)
>
> OK, we can add the external clocks to differentiate later, when the driver can
> handle them.
>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Reviewed-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
