OF NDFC

Is anybody working on the device-tree-aware ppc 44x NAND flash controller (ndfc)  driver?

Thanks,
Valentine.

On Wed, 5 Sep 2007 22:17:03 +0400
Valentine Barshak [off-list ref] wrote:

Is anybody working on the device-tree-aware ppc 44x NAND flash controller (ndfc)  driver?

Not to my knowledge.  We sort of need a decent binding for NAND flash
in general first.  And David's recent flash binding doesn't address
NAND flash.

It's on my list of things to do, but if someone gets there first then
great.

josh

quoted

Is anybody working on the device-tree-aware ppc 44x NAND flash 
controller (ndfc)  driver?

Not to my knowledge.  We sort of need a decent binding for NAND flash
in general first.

Not really.  You can put the NAND controller in the device
tree without describing the NAND flash itself -- and for that,
you only need a "name", "compatible", "reg", and maybe some
interrupt stuff.


Segher

On Thu, 6 Sep 2007 15:06:03 +0200
Segher Boessenkool [off-list ref] wrote:

quoted

quoted

Is anybody working on the device-tree-aware ppc 44x NAND flash 
controller (ndfc)  driver?

Not to my knowledge.  We sort of need a decent binding for NAND flash
in general first.

Not really.  You can put the NAND controller in the device
tree without describing the NAND flash itself -- and for that,
you only need a "name", "compatible", "reg", and maybe some
interrupt stuff.

He said driver.  To test a driver, you'd need the binding for both the
controller, and the NAND flash it controls.  Otherwise, the driver
isn't going to do much :).

josh

Josh Boyer wrote:

On Thu, 6 Sep 2007 15:06:03 +0200
Segher Boessenkool [off-list ref] wrote:

quoted

quoted

quoted

Is anybody working on the device-tree-aware ppc 44x NAND flash 
controller (ndfc)  driver?

Not to my knowledge.  We sort of need a decent binding for NAND flash
in general first.

Not really.  You can put the NAND controller in the device
tree without describing the NAND flash itself -- and for that,
you only need a "name", "compatible", "reg", and maybe some
interrupt stuff.

He said driver.  To test a driver, you'd need the binding for both the
controller, and the NAND flash it controls.  Otherwise, the driver
isn't going to do much :).

josh
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AFAIK, NAND flash is autodetected by reading it's ID at runtime, so 
there should be no need for flash bindings.
Thanks,
Valentine.

On Thu, 06 Sep 2007 17:30:08 +0400
Valentine Barshak [off-list ref] wrote:

AFAIK, NAND flash is autodetected by reading it's ID at runtime, so 
there should be no need for flash bindings.

Well, I'm not really sure.  CFI and JEDEC can both be probed as well,
and we're working on a binding there.  But if you think you can come up
with a driver for NDFC that doesn't require some kind of device tree
description of the devices it controls, then by all means go for it.

josh

quoted

AFAIK, NAND flash is autodetected by reading it's ID at runtime, so
there should be no need for flash bindings.

Well, I'm not really sure.  CFI and JEDEC can both be probed as well,
and we're working on a binding there.

JEDEC cannot be reliably probed.  CFI can be _almost_ probed,
you need to know the interleaving though, to handle some edge
cases.  Oh, and you need to know it _is_ CFI, of course.

But if you think you can come up
with a driver for NDFC that doesn't require some kind of device tree
description of the devices it controls, then by all means go for it.

I don't know whether NAND can be reliably probed; most "standard"
NAND devices can be, but I don't know what standards are involved
here, if any.  We'll need some MTD people help here.

OTOH, it definitely is better to describe only the NAND controller
and not the devices, than to put nothing at all in the device tree.
We had this same situation with NOR flash before, already...


Segher