From mboxrd@z Thu Jan 1 00:00:00 1970 From: mark.rutland@arm.com (Mark Rutland) Date: Mon, 13 Oct 2014 11:32:20 +0100 Subject: [RFC 4/7] ARM: dts: add support for Vybrid running on Cortex-M4 In-Reply-To: References: Message-ID: <20141013103219.GE14739@leverpostej> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Sun, Oct 12, 2014 at 07:13:58PM +0100, Stefan Agner wrote: > This adds an initial device tree to run Linux on the Cortex-M4 on > Vybrid. > > HACK: Because we include armv7-m.dtsi, the soc node happens to > be before the clock node. This is a problem for vf610-clk.c, which > tries to optain the fixed clocks defined in the clock nodes. But > because clock drivers are initialized sequencially, and we do not > have support for deferred probing, the clock initialization fails > horrible. > Move the armv7-m.dtsi include to the bottom to temporarily work > work around this... > > Signed-off-by: Stefan Agner > --- > Maybe a dummy soc entry in armv7-m.dtsi also helps here. But a > hack as well. Is it common acceptable that the kernel depends > on DTS order? The kernel should not depend on DTS ordering. We should sort out deferred probing if there is an issue with it. [...] > + clocks { > + #address-cells = <1>; > + #size-cells = <0>; > + > + sxosc { > + compatible = "fixed-clock"; > + #clock-cells = <0>; > + clock-frequency = <32768>; > + }; > + > + fxosc { > + compatible = "fixed-clock"; > + #clock-cells = <0>; > + clock-frequency = <24000000>; > + }; > + }; Please get rid of the clocks node and put these under the root node. There is nothing special about clocks, and the kernel in no way handles a clocks node specially. > + > + soc { > + aips0: aips-bus at 40000000 { > + compatible = "fsl,aips-bus", "simple-bus"; > + #address-cells = <1>; > + #size-cells = <1>; > + reg = <0x40000000 0x70000>; Out of curiosity, given that this can be driven as a simple-bus, what do the aips bus registers allow to be configured? Thanks, Mark.