Re: [PATCH] of: Have of_device_add call platform_device_add ratherthan device_add

From: Jason Gunthorpe
Date: Wed Nov 21 2012 - 12:44:45 EST


On Wed, Nov 21, 2012 at 03:51:04PM +0000, Grant Likely wrote:
> On Wed, 21 Nov 2012 00:24:48 -0700, Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx> wrote:
> > This allows platform_device_add a chance to call insert_resource
> > on all of the resources from OF. At a minimum this fills in proc/iomem
> > and presumably makes resource tracking and conflict detection work
> > better.
> >
> > Signed-off-by: Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx>
> > drivers/of/device.c | 2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > Tested on PPC32 and ARM32 embedded kernels.
> >
> > diff --git a/drivers/of/device.c b/drivers/of/device.c
> > index 4c74e4f..a5b67dc 100644
> > +++ b/drivers/of/device.c
> > @@ -62,7 +62,7 @@ int of_device_add(struct platform_device *ofdev)
> > if (!ofdev->dev.parent)
> > set_dev_node(&ofdev->dev, of_node_to_nid(ofdev->dev.of_node));
> >
> > - return device_add(&ofdev->dev);
> > + return platform_device_add(ofdev);
> > }
> >
> > int of_device_register(struct platform_device *pdev)
>
> This has the side effect of moving all devices at the root of the tree
> from /sys/devices/ to /sys/devices/platform. It also has the possibility
> of breaking if any devices get registered with overlapping regions. I
> think there are some powerpc 5200 boards that do this, and I'm not sure
> about the larger Power boxen.

Okay, I'll try to test your patch.

I know sensible overlapping seems to work:

e0000000-e7ffffff : PCIe 0 MEM
e0000000-e000ffff : 0000:00:01.0
e0000000-e0000fff : /pex@e0000000/chip@0/chip_control@0
e0000008-e000000b : dat
e0000008-e000000b : dat
e000000c-e000000f : set
e000000c-e000000f : set
e0000010-e0000013 : dirin
e0000010-e0000013 : dirin

Which is nesting the generic gpio driver under a larger region..

And:
f1010100-f101013f : /internal@f1000000/gpio@10100
f1010100-f1010103 : /internal@f1000000/chip_cfg@0

Which is nesting a register set for one OF platform_device under
another.

It seems to be handled automatically.

My motivations are two fold:
- Having a mostly empty /proc/iomem isn't great for diagnostics
- I'll send a patch today that adds some more code to
platform_device_add

Thanks Grant,
Jason
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/