From mboxrd@z Thu Jan 1 00:00:00 1970 From: mark.rutland@arm.com (Mark Rutland) Date: Mon, 2 Feb 2015 15:41:49 +0000 Subject: [PATCH v3 5/5] ARM: dts: Alpine platform devicetree In-Reply-To: References: <54cf5d8c.sl7aclyeuuh66jXt%tsahee@annapurnalabs.com> <20150202134051.GB21175@leverpostej> Message-ID: <20150202154149.GD21175@leverpostej> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Feb 02, 2015 at 03:27:48PM +0000, Tsahee Zidenberg wrote: > Thank you for your review! > > On 2 February 2015 at 15:40, Mark Rutland wrote: > > On Mon, Feb 02, 2015 at 11:20:44AM +0000, Tsahee Zidenberg wrote: > >> + arch-timer { > >> + compatible = "arm,cortex-a15-timer", > >> + "arm,armv7-timer"; > >> + interrupts = > >> + , > >> + , > >> + , > >> + ; > >> + clock-frequency = <0>; /* Filled by loader */ > > > > Your loader doesn't configure CNTFRQ? > > > > Not currently. setting CNTFRQ must be done in the firmware, to be > valid across all CPUs and through power-cycles. This isn't supported > on current firmware, which is used in currently available devices. I > will add this as a required feature from next-gen firmware. > clock-frequency property is read by linux-kernel before attempting to > read CNTFRQ. Ok. The "clock-frequency" property is unfortunately a poor workaround for CNTFRQ not being set, due to CNTFRQ being exposed to guests in the presence of virtualisation (and potentially userspace were we to have a VDSO). > > > >> + /* North Bridge Service Registers */ > >> + sysfabric-service at fb070000 { > >> + compatible = "al,alpine-sysfabric-service", "syscon", "simple-bus"; > >> + reg = <0x0 0xfb070000 0x0 0x10000>; > >> + }; > > > > That compatible list makes no sense whatsoever. > > > > Why is "simple-bus" on the end? > > > > Nodes that are used with "syscon_regmap_lookup_by_compatible" appear > both with and without compatibility to "simple-bus" in the > device-trees. > examples with: "fsl,imx6q-anatop", "xlnx,zynq-slcr" > examples without: "fsl,imx6q-iomuxc-gpr", "rockchip,rk3066-pmu" > Both ways work, I'm not if there is reasoning behind this difference > in current device-trees or which is the better example to follow. I > have no problem working either way. Is there a consensus on this? The "simple-bus" entry is wrong, and should be removed. In other cases it's also likely to be wrong, but I'd have to inspect them to be sure. Mark.