On Wed, Jun 26, 2013 at 02:12:06PM +0100, Grant Likely wrote: > On Wed, Jun 26, 2013 at 1:44 PM, Sebastian Hesselbarth > <sebastian.hesselbarth@xxxxxxxxx> wrote: > > On 06/26/13 12:03, Grant Likely wrote: > >> > >> On Wed, Jun 26, 2013 at 7:00 AM, Hiroshi Doyu <hdoyu@xxxxxxxxxx> wrote: > >>> > >>> Grant Likely <grant.likely@xxxxxxxxxxxx> wrote @ Tue, 25 Jun 2013 > >>> 19:52:33 +0200: > >>> > >>>>> Here's my workaround. I need to call of_detach_node() with OF_DYNAMIC > >>>>> to avoid duplicated device registration. > >>>> > >>>> > >>>> Gah! my eyes! > >>>> > >>>> Don't do that. It is incredibly problematic. Look at inhibiting > >>>> duplicate device creation instead. > >>> > >>> > >>> I may not follow this thread correctly, but could anyone point out the > >>> above "inhibiting duplicate device creation" if there's already such > >>> solution? > >> > >> > >> No, the solution doesn't exist yet, but it wouldn't be hard to > >> implement. What you need to do is to add a struct device pointer to > >> struct device_node, and set the pointer to the struct device when > >> of_platform_device_create creates a device. (it would also need to be > >> set for early_platform_device creation, but that's not something that > >> should affect you). You would also add a check to > >> of_platform_device_create to check if the device pointer is already > >> set. If it is, then skip creation of the device. > > > > > > Grant, > > > > What about the other way round, i.e. check if there is a device with > > .of_node pointed to the struct device_node currently at > > of_platform_device_create? > > > > That will avoid adding struct device to struct device_node which you > > fought against for good reasons. > > The main thing is that it means searching through the entire list of > platform devices every time a new platform device is created. That > seems unnecessarily expensive to me. There's not really much reason to not add a pointer to the struct device of a device_node because you can already obtain the platform_device by calling of_find_device_by_node(). That doesn't work early, but if that gets fixed, then of_find_device_by_node() could also be used. And since adding a struct device * to device_node is pretty much required to fix of_platform_device_create() for early, of_find_device_by_node() can be implemented much more efficiently. > > Also, I guess of_platform_device_create could be exported and used > > by anyone who wants to create platform_devices early. > > Yes, but in that case it is probably better for them to call > of_platform_populate early if of_platform_device_create is fixed to > support early calling. Then you'd just set up all the devices earlier > in init, allow drivers that support early probing to do so, and then > everything else uses the normal initcall path. I've been bugged by the recent additions in drivers/irqchip lately because they all rely on only the device_node and therefore none of the functions that require a struct device can be used. If things can indeed be fixed to call of_platform_populate() early that would restore a whole lot of consistency. Thierry
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