Re: Device Tree Child Node Parsing Question

On 12/26/2014 01:40 PM, Rob Herring wrote:

On Tue, Dec 23, 2014 at 10:34 AM, Thor Thayer
[off-list ref] wrote:

quoted

Hi,

What is the best way to queue devicetree child nodes so the node is passed
in the platform_device pointer to the probe() function?

Documentation/devicetree/usage-model.txt has the following:

"For Linux DT support, the generic behaviour is for child devices to be
registered by the parent's device driver at driver .probe() time."

"Actually, it turns out that registering children of some platform_devices
as more platform_devices is a common pattern, and the
device tree support code reflects that and makes the above example
simpler.  The second argument to of_platform_populate() is an
of_device_id table, and any node that matches an entry in that table
will also get its child nodes registered."


I tried calling of_platform_populate() in the probe of the a10_sysctl node
but it doesn't appear to setup the platform device data properly for the
sub-child nodes.

<snip>

This should work. There are quite a few users already including unit
tests. Can you tell what you are doing differently from those users?

Rob

quoted

<snip>

Just to tie up this conversation in case anyone else has an issue, it 
ended up being my debug issue. The of_platform_populate() was working 
properly. The issue was that I was also calling a mfd_add_devices() 
using a devices table and I was watching the mfd_add_devices() probe. 
Simply removing the mfd_add_devices() and the table and using 
of_platform_populate() as below worked.

of_platform_populate(spi->dev.of_node, a10sycon_spi_of_match,
		     NULL, &spi->dev);

Thanks!
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