GPMC in device tree

[Ran Shalit]

On Tue, Aug 4, 2015 at 11:31 PM, Scott Wood <scottwood at freescale.com> wrote:
> On Tue, 2015-08-04 at 23:26 +0300, Ran Shalit wrote:
>> On Tue, Aug 4, 2015 at 9:54 PM, Scott Wood <scottwood at freescale.com> wrote:
>> > On Tue, 2015-08-04 at 18:29 +0300, Ran Shalit wrote:
>> > > Hello,
>> > >
>> > > I would please like to ask if describing flash nor used with GPMC,
>> > > whould be done as described in:
>> > > https://www.kernel.org/doc/Documentation/devicetree/bindings/mtd/gpmc-nor.txt
>> > > It is described in the above link as "TI's GPMC", so I'm not sure if
>> > > it is relevent for powerpc too.
>> >
>> > That binding is for TI GPMC.
>> >
>> > Are you saying you have some PPC chip that has a flash controller called
>> > GPMC?
>> >
>> > -Scott
>> >
>>
>> Hi Scott,
>>
>> Thanks, I've worked with TI's chips, so I now understand that I made
>> here some confusion...
>> It is GPCM , not GPMC, my mistake.
>> We already configured it in u-boot, but on doing read/write from
>> kernel it doesn not work.
>> It seems that for the linux to use the correct driver, we need to
>> define the nor in the device tree.
>> Is there any example how to define nor GPCM in device tree ? Is it
>> possible not to override the existing GPCM configuration ?
>
> Pretty much all of the mpc8xxx/qoriq device trees have GPCM NOR defined.  See
> Documentation/devicetree/bindings/powerpc/fsl/lbc.txt and examples such as
> arch/powerpc/boot/dts/p4080ds.dts (part of the lbc node is in
> arch/powerpc/boot/dts/fsl/p4080si-post.dtsi).
>
> Linux will not change the GPCM configuration.
>
> -Scott
>

On more thing, if I may.
The localbus is also connected to nvram & cpld.
I've noticed that read/write works well, even though I didn't define
anything in device tree.
Is there any reasom to add these devices into device tree, or can we
use the cpld and nvram without the definition in device tree ?

Thanks,
Ran