On Fri, Mar 02, 2012 at 10:15:11AM +0100, Simon Guinot wrote:
> Hi Jason,
>
> On Thu, Mar 01, 2012 at 06:20:55PM +0000, Jason Cooper wrote:
> > Converted register address to a variable so that it could be set from
> > fdt. Also, pull clock frequency from fdt and clean up failure logic a
> > bit.
> >
> > Same as rtc-mv, this device is used in all kirkwood boards. So, it is
> > placed in kirkwood.dtsi.
> >
> > Signed-off-by: Jason Cooper <ja...@lakedaemon.net>
> > ---
> > arch/arm/boot/dts/kirkwood.dtsi | 6 +++++
> > arch/arm/mach-kirkwood/board-dt.c | 1 -
> > arch/arm/mach-kirkwood/common.c | 2 +-
> > arch/arm/mach-kirkwood/common.h | 1 -
> > drivers/watchdog/orion_wdt.c | 44
> > ++++++++++++++++++++++++++----------
> > 5 files changed, 39 insertions(+), 15 deletions(-)
> >
> > diff --git a/arch/arm/boot/dts/kirkwood.dtsi
> > b/arch/arm/boot/dts/kirkwood.dtsi
> > index 5fb185c..bf28424 100644
> > --- a/arch/arm/boot/dts/kirkwood.dtsi
> > +++ b/arch/arm/boot/dts/kirkwood.dtsi
> > @@ -8,5 +8,11 @@
> > reg = <0xf1010300 0x1f>;
> > interrupts = <53>;
> > };
> > +
> > + wdt@fed20300 {
> > + compatible = "marvell,orion-wdt";
> > + reg = <0xfed20300 0x28>;
> > + clock-frequency = <200000000>;
> > + };
>
> How this will work for boards using a different clock frequency (TCLK) ?
> Here, we could have 166MHz for example.
>
> Can this node be updated during the board initialization with a detected
> TCLK value ?
>
> Or maybe this clock-frequency can reference a TCLK frequency defined in
> a board specific dts (I don't know if the DT format allow such things) ?
Grr... good catch. I originally had this in kirkwood-dreamplug.dts,
which is always 200000000. That's not the case in kirkwood.dtsi. What
I would like to do, and I haven't had time to look into it (I thought I
would tackle it later as a refinement :-( ), is a reference of some
sort, eg:
in kirkwood.dtsi:
/ {
compatible = "marvell,kirkwood";
tclk:clock-frequency = <200000000>;
wdt@fed20300 {
compatible = "marvell,orion-wdt";
reg = <0xfed20300 0x28>;
clock-frequency = &tclk;
};
};
then, in kirkwood-foobar.dts
/include/ "kirkwood.dtsi"
/ {
model = "foobar";
compatible = "...";
tclk:clock-frequency = <166000000>;
};
but I'm not sure if that would work.
In any case, the simplest answer is to set clock-frequency in
kirkwood-dreamplug.dts as a root node property, and then each driver
that needs tclk, requests the clock-frequency from the root node.
Hopefully, Grant can chime in on this one.
Thanks for the review,
Jason.
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