From mboxrd@z Thu Jan 1 00:00:00 1970 From: grant.likely@secretlab.ca (Grant Likely) Date: Mon, 23 May 2011 09:23:54 -0600 Subject: [PATCH 2/2] drivers/amba: probe via device tree In-Reply-To: <20110521234725.GB17672@n2100.arm.linux.org.uk> References: <1305829704-11774-1-git-send-email-robherring2@gmail.com> <20110519233958.GB18181@ponder.secretlab.ca> <4DD66B8A.5040404@gmail.com> <201105201621.03801.arnd@arndb.de> <4DD68614.6090209@gmail.com> <20110521234725.GB17672@n2100.arm.linux.org.uk> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Sat, May 21, 2011 at 5:47 PM, Russell King - ARM Linux wrote: > On Sat, May 21, 2011 at 11:42:34AM -0600, Grant Likely wrote: >> Russell, it seems to me that the primary behaviour that amba_bus has >> over platform_bus is the clock management, and secondarily >> verification of the type of device by the device id. ?Am I correct, or >> am I missing something? > > It matches by vendor/device ID just like PCI does, and does the bus > clock management and power management in a really nice way, which I > doubt platform devices will ever do. > > The way this discussion is going, I'm going to suggest that we also > convert PCI stuff to being platform devices too. ?I don't see the > point of PCI existing for all the same reasons being given in this > thread. I certainly don't see that as being the direction this discussion is going. I see a serious question about how best to model AMBA primecell devices in the device tree, and a similarly serious question about whether to instantiate them as platform_devices or amba_devices. Modelled behaviour in this case (clock/power management) is particularly important, and you're right, platform_devices will never implement that behaviour in the core code (this issue has already been pushed back on; see discussions about omap_device). g.