From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@arm.linux.org.uk (Russell King - ARM Linux) Date: Mon, 3 Aug 2015 20:09:35 +0100 Subject: [PATCH 0/2] drivers: PL061: Add platform driver probing support In-Reply-To: <20150803162623.GB30867@kroah.com> References: <1438585198-8764-1-git-send-email-zhaoshenglong@huawei.com> <20150803075848.GH7557@n2100.arm.linux.org.uk> <55BF33AD.5040502@huawei.com> <20150803094923.GI7557@n2100.arm.linux.org.uk> <20150803162623.GB30867@kroah.com> Message-ID: <20150803190935.GL7557@n2100.arm.linux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Aug 03, 2015 at 09:26:23AM -0700, Greg Kroah-Hartman wrote: > On Mon, Aug 03, 2015 at 10:49:23AM +0100, Russell King - ARM Linux wrote: > > On Mon, Aug 03, 2015 at 05:26:05PM +0800, Shannon Zhao wrote: > > > Hi Russell, > > > > > > On 2015/8/3 15:58, Russell King - ARM Linux wrote: > > > > On Mon, Aug 03, 2015 at 02:59:56PM +0800, Shannon Zhao wrote: > > > >> From: Shannon Zhao > > > >> > > > >> According to ACPI SPEC, it supports ARM boards to use "GPIO-signaled > > > >> ACPI Events". These events can be used for input events. And to QEMU, it > > > >> uses GPIO PL061 controller for input events. > > > >> > > > >> These two patches add platform driver support for PL061 probed by DT or > > > >> ACPI. > > > > > > > > This certainly is incorrect for DT, and is probably wrong for ACPI too. > > > > DT creates amba devices, so binds via the amba device driver. > > > > > > > > > > Oh, sorry. The changes for DT are not necessary. But for ACPI I think it > > > needs to convert pl061 to platform device since ACPI doesn't support > > > AMBA devices. The Pl011 also does the same thing to support ACPI > > > probing. See drivers/tty/serial/amba-pl011.c > > > > Maybe rather than having every AMBA driver also converted to a platform > > driver (which GregKH hates) maybe ACPI should support the AMBA bus > > instead? > > > > Greg? > > The ACPI developers have been doing work to allow a driver to handle > getting the resources from either DT or ACPI no matter what bus it is > on, so converting anything to a platform driver shouldn't be needed. > > but I don't really know the details here, and this isn't being sent to > the ACPI mailing list, so I don't know what to suggest... Greg, You're the one who's said many times that you'd like to see platform devices and platform device drivers to go away. So, when I give you the opportunity to comment on platform devices being used to augment existing device drivers such as the AMBA bus drivers (which you've also previously said is a more preferable way to use the driver model) why not support that view? Right now, there seems to be a move to convert _all_ AMBA device drivers to become dual-drivers: an amba bus driver and a platform driver. Is that something you really want to see, irrespective of ACPI issues? -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net.