On 08/13/2013 02:17 PM, Dinh Nguyen wrote: > On Tue, 2013-08-13 at 14:10 -0600, Stephen Warren wrote: >> On 08/13/2013 01:58 PM, Dinh Nguyen wrote: >>> On Tue, 2013-08-13 at 13:52 -0600, Stephen Warren wrote: >>>> On 08/12/2013 09:49 AM, dinguyen@xxxxxxxxxx wrote: >>>>> From: Dinh Nguyen <dinguyen@xxxxxxxxxx> >>>>> >>>>> Add bindings for SD/MMC for SOCFPGA. >>>>> Add "syscon" to the "altr,sys-mgr" binding. >> >>>>> diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi >>>> >>>>> sysmgr@ffd08000 { >>>>> - compatible = "altr,sys-mgr"; >>>>> + compatible = "altr,sys-mgr", "syscon"; >>>> >>>> That seems like an unrelated change? >>> >>> This patch is to enable SD/MMC for SOCFPGA. The "syscon" is needed in >>> dw_mmc-socfpga.c as the clock phases for the SD IP is controlled by >>> registers in "altr,sys-mgr". >> >> But nothing in the dwmmc nodes refers to the syscon node, so how can the >> syscon driver possibly provide services to the MMC driver; the MMC >> driver won't be able to find it. I hope there's no back-door assumption >> that some syscon exists, and that there's only one of them... > > In dw_mmc-socfpga.c: > > priv->sysreg = syscon_regmap_lookup_by_compatible("altr,sys-mgr"); > > then, uses regmap_write() to set the correct values from > "altr,dw-mshc-sdr-timing". Uggh. There should really be a phandle from the MMC node to the syscon node to specify the connectivity. What if there ends up being 2 HW modules that are sys-mgr? At the very least, the binding for any device that's affected by the sys-mgr should specify that some other node must exist with that compatible value, to provide XXX services for it. But, I wonder if the altr,dw-mshc-sdr-timing property shouldn't be part of the syscon node itself? (Probably best to ignore my ack for now given this new information) > This was a suggestion from Arnd. It seems that this part of patch is > causing alot of confusion, I should just split the patches out? A separate patch to change that compatible value probably would make sense; by the sound of it, that change would also be required for a lot of other devices on the SoC; it's not just specific to MMC? -- 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