On Saturday, June 18, 2011 6:18 AM, Grant Likely wrote: > On Sat, Jun 18, 2011 at 4:17 AM, Dmitry Torokhov wrote: >> On Thu, Jun 16, 2011 at 01:27:32PM -0600, Grant Likely wrote: >>> On Tue, Jun 14, 2011 at 11:08:11AM +0200, David Jander wrote: >>>> Use a threaded interrupt handler in order to permit the handler to use >>>> a GPIO driver that causes things like I2C transactions being done inside >>>> the handler context. >>>> Also, gpio_keys_init needs to be declared as a late_initcall, to make sure >>>> all needed GPIO drivers have been loaded if the drivers are built into the >>>> kernel. >>> >>> ...which is a horrid hack, but until device dependencies can be >>> described, it isn't one that can be solved easily. >>> >> >> I really do not want to apply this... Currently the order of >> initialization does not matter since nothing actually happens until >> corresponding device appears on the bus. Does the OF code creates >> devices before all resources are ready? > > It's not an OF problem. The problem is that all the platform_devices > typically get registered all at once at machine_init time (on arm), > and if the gpio expander isn't a platform_device, (like an i2c gpio > expander which would end up being a child of a platform_device), then > it won't be ready. The real problem is that we have no mechanism for > holding off or deferring a driver probe if it depends on an > asynchronous resource. To avoid the registration order issue, isn't the proper fix to use a "setup" method in the gpio expander driver? The gpio-pca953x.c driver has this and I use it to hook the gpio_keys driver to those gpios. The registration order ends up being: i2c-gpio as a platform_device in the machine init code pca9539 as part of the i2c_board_info for the i2c-gpio device gpio-keys as a platform_device via the .setup callback of pca9539 Regards, Hartley-- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
