On Thu, Dec 24, 2015 at 04:42:25PM +0300, Peter Mamonov wrote: > On Thu, 24 Dec 2015 12:48:37 +0300 > Peter Mamonov <pmamonov@xxxxxxxxx> wrote: > > > On Wed, 23 Dec 2015 18:04:43 +0100 > > Alexander Aring <alex.aring@xxxxxxxxx> wrote: > > > > > On Wed, Dec 23, 2015 at 07:56:44PM +0300, Peter Mamonov wrote: > > > > On Wed, 23 Dec 2015 17:35:51 +0100 > > > > Alexander Aring <alex.aring@xxxxxxxxx> wrote: > > > > > > > > > On Wed, Dec 23, 2015 at 07:10:58PM +0300, Peter Mamonov wrote: > > > > > > Dear All, > > > > > > > > > > > > I've ported an UHCI driver from the u-boot to the barebox > > > > > > (WIP). To interoperate with the EHCI driver, the UHCI driver > > > > > > should be probed ater the EHCI driver. Both drivers are binded > > > > > > via the device tree mechanism. How can i achieve the correct > > > > > > probe order? > > > > > > > > > > > > > > > > Normally this should done by returning "-EPROBE_DEFER" inside > > > > > the probe function. There was some RFC last years for supporting > > > > > EPROBE_DEFER [0] and it seems these are mainline. > > > > > > > > > > However you need some bool which indicates that the EHCI driver > > > > > is probed. > > > > > > > > Thanks, Alex. As i understand, this is the linux-way solution. > > > > > > > > Sasha, is it ok to add a global variable to indicate the EHCI > > > > presence? Or should we follow the way proposed by the mentioned > > > > RFCs, i.e. introduce dependencies between drivers? > > > > > > > > > > mhhh, maybe a simple "get_device_by_name" works here. > > > > > > If returning NULL then return -EPROBE_DEFER. Don't know if this is a > > > good solution, name need to be unique then. > > > > > > > > > btw: > > > Just found that "of_find_device_by_node" returns -EPROBE_DEFER when > > > nothing was found. This was introduced by the patch series. > > > > I like this approach better, than introducing a global variable. > > Will look further into it. > > Unfortunately of_find_device_by_node() returns a valid pointer to > the device before the device probe function is called. I guess > get_device_by_name() behaves in the same way. This looks buggy. There should be a way to tell if a device has been probed or not before working with the device returned by of_find_device_by_node() or get_device_by_name(). The easiest way is probably to check for dev->driver. This is not enough though to tell if the device probe has failed, not yet executed, or deferred. Maybe we could store the probe status of a device in struct device_d itself. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
