[PATCH 06/14] ARM: kirkwood: convert uart0 to devicetree.

Grant Likely grant.likely at secretlab.ca
Fri Mar 9 08:31:39 EST 2012


On Wed, Mar 07, 2012 at 02:27:23PM -0500, Jason wrote:
> On Wed, Mar 07, 2012 at 06:31:31PM +0000, Arnd Bergmann wrote:
> > On Wednesday 07 March 2012, Jason Cooper wrote:
> > > +       serial at f1012000 {
> > > +               compatible = "ns16550a";
> > > +               reg = <0xf1012000 0xff>;
> > > +               reg-shift = <2>;
> > > +               interrupts = <33>;
> > > +               clock-frequency = <200000000>;
> > > +       };
> > 
> > I just noticed that the length here should be inclusive, i.e. 0x100 not 0xff.
> > This is different from the way we define resources in Linux.
> 
> Grrr.  Now I'm getting frustrated.  I'm trying to boot without
> earlyprintk.  Evidently, something is wrong with the above, because the
> device boots all the way up (blinky lights come on), but I get no
> messages after the usual "Uncompressing Linux... done, booting the
> kernel."
> 
> Here's my most recent attempt:
> 

I see that you've resolved your problem, but some comments below on the
device node:

>         serial at f1012000 {
>                 device_type = "serial";

Never use device_type.  It should only ever appear in the memory node, and
I plan to remove it from there too.

>                 compatible = "ns16550a";
>                 reg = <0xf1012000 0x100>; /*phys addr*/
>                 virt-reg = <0xfed12000>;  /*virt addr*/

Don't use virt-reg.  Nothing in the kernel uses it and the kernel will
make it's own decision about virtual address mapping.

>                 reg-shift = <2>;
>                 reg-io-width = <1>;

1 is the default for reg-io-width.  No need to have this property.  It
should only be used if the device requires 32 bit accesses.

>                 interrupts = <33>;
>                 current-speed = <115200>;
>                 interrupt-parent = <&intc>;
>                 clock-frequency = <200000000>;
>         };
> 

g.


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