On Tue, 2014-04-08 at 15:38 +0200, Steffen Trumtrar wrote: > Hi! > > On Mon, Apr 07, 2014 at 04:54:07PM -0500, tthayer@xxxxxxxxxx wrote: > > From: Thor Thayer <tthayer@xxxxxxxxxx> > > > > Addition of the Altera SDRAM controller bindings and device > > tree changes to the Altera SoC project. > > [snip] > > + > > +Required properties: > > +- compatible : "altr,sdr-ctl", "syscon"; > > + Note that syscon is invoked for this device to support the FPGA > > + bridge driver, EDAC driver and other devices that share the > > + registers. > > +- reg : Should contain 1 register ranges(address and length) > > I haven't really thought this through, but why would the FPGA bridge driver > access the sdram controller? For releasing the resets in fpgaportrst ? Or is > there more? Hi Steffan. No, not for resets. We need to enable the FPGA to SDRAM path. Our SDRAM controller allows FPGA master access to the SDRAM. > Wouldn't it be more appropriate to represent those bits as a reset-controller to > some hypothetical IP core driver? > Then you could have something like > > hps2fpga@c0000000 { > ipcore@0 { > resets = <&sdr 1>; > reset-names = "foo"; > resets = <&rst 96>; > reset-names = "bar"; > (...) > }; > > ipcore@1000 { > resets = <&rst 96>; > reset-names = "baz"; > (...) > }; > }; > > And you would always have the correct bridges released out of reset for your > IP core. Does the FPGA bridge driver do more? I think that is basically it. > Where we maybe could run into problems though is the early_init stuff. > > I think syscon is nice for some things, but we should try not to overuse it. Understood. In this case, syscon seems to be appropriate. > > Regards, > Steffen > > > +Example: > > + sdrctl@ffc25000 { > > + compatible = "altr,sdr-ctl", "syscon"; > > + reg = <0xffc25000 0x1000>; > > + }; > > diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi > > index df43702..6ce912e 100644 > > --- a/arch/arm/boot/dts/socfpga.dtsi > > +++ b/arch/arm/boot/dts/socfpga.dtsi > > @@ -676,6 +676,11 @@ > > clocks = <&l4_sp_clk>; > > }; > > > > + sdrctl@ffc25000 { > > + compatible = "altr,sdr-ctl", "syscon"; > > + reg = <0xffc25000 0x1000>; > > + }; > > + > > rstmgr@ffd05000 { > > compatible = "altr,rst-mgr"; > > reg = <0xffd05000 0x1000>; > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html