Re: [PATCH V2 2/2] mtd/maps/mtd-ram: add an of-platform driver

Wolfram Sang
2009-06-06T11:19:42Z

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On Sat, Jun 06, 2009 at 09:14:08AM +0100, David Woodhouse wrote:

> On Fri, 2009-06-05 at 14:05 +0200, Wolfram Sang wrote:
> > Create an of-aware driver using the now exported generic functions from
> > plat-ram.c. Also add the documentation for the binding. Partitions are
> > not yet supported. Tested on a phyCORE-MPC5200B-IO.
>
> Do we have an ack for the device-tree bindings?
>
> It _would_ be possible to hook up RAM through the existing of_physmap
> driver, I think -- although it would be slightly less efficient that
> way.
>
> Maybe cleaner from the device-tree POV though. And if we want to put a
> special case in the _code_ to make it more efficient, we can do that.

During development, I also checked physmap_of.c and found this binding:

{
.type = "rom",
.compatible = "direct-mapped"
},

which made some sense to me and I thought about .type = "ram". However, I then
found this in the code:

/* Helper function to handle probing of the obsolete "direct-mapped"
* compatible binding, which has an extra "probe-type" property
* describing the type of flash probe necessary. */
static struct mtd_info * __devinit obsolete_probe(struct of_device *dev,
struct map_info *map)
{
[...]

dev_warn(&dev->dev, "Device tree uses obsolete \"direct-mapped\" "
"flash binding\n");

My conclusion was then that a mtd-ram binding wouldn't belong here, but I have
maybe misinterpreted things...

Regards,

Wolfram

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