* Rob Herring <robherring2@xxxxxxxxx> [140421 06:47]: > On Fri, Apr 18, 2014 at 6:24 PM, Tony Lindgren <tony@xxxxxxxxxxx> wrote: > > * Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> [140418 16:04]: > >> On Fri, Apr 18, 2014 at 02:58:48PM -0700, Tony Lindgren wrote: > >> > Oh come on, let's stop pretending it's not broken. And it's way worse with > >> > device tree as there's nothing making sure the resources for a driver > >> > are set up before the driver probes. And we've been unable to fix just > >> > this issue alone for about six months now. It's also broken beyond that. > >> > It's called of_platform_bus yet it won't even pass the platform_data > >> > as auxdata to the devices on a sub-bus instantatiated like I2C. > >> > >> Isn't there a much simpler solution to the platform device IRQ problem? > >> > >> Rather than trying to fix it at the point where the resources are > >> created, why not just *not* have DT create the IRQ resources in the > >> first place, and instead have platform_get_irq() (which is the function > >> which should be used to get an IRQ) be the actor to do whatever is > >> necessary to return the IRQ(s) ? > > > > Yeah why not. I don't see why we would need to do all this of_* special > > trickery for much anything beyond parsing the binding. > > That can work, but it will still need something like > of_find_irq_domain() to determine whether to return -EPROBE_DEFER or > not. Right. Naturally let's do whatever it takes to first fix this issue in a minimal way first for the -rc cycle so we can do the longer term changes needed. > You could also go in the other direction and don't create the device > until the resources can be resolved. Unlike any of the other > solutions, that would work for amba bus as well although we may never > have a case where we need this with the amba bus. This would require > making of_platform_populate be callable multiple times, but there are > already some other reasons for wanting to do that. Specifically, I > would like the core code to call of_platform_populate with default > options and then only platforms with non-default options need a call > to of_platform_populate. I like this idea as this would also probably remove the the numerous dmesg errors we are currently getting for drivers reprobing with -EPROBE_DEFER. In the long term we should have platform bus just call a set of standardized functions implemented by whatever the data source might be. That way we can limit the use of of_* functions in device drivers to just parsing of custom bindings in the drivers and use bus specific functions for everything else. > >> Yes, I know we have some drivers which use platform_get_resources() with > >> IORESOURCE_IRQ, but they should really use the right accessor. And those > >> who just dereference the resource array directly... get what's coming > >> (though of course they have to be fixed.) > > > > $ git grep IORESOURCE_IRQ drivers/ | grep platform_get_resource | wc -l > > 179 > > Certainly, this is worthwhile clean-up no matter what the solution. Yeah agreed. But let's also consider the IORESOURCE_IRQ as just another source for for the bus or driver data in addition to the DT parsed data. Both sources of data should work just fine with platform_bus even without cleaning up the drivers. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
