On 12/18/13 3:21 PM, Arnd Bergmann wrote: > On Wednesday 18 December 2013, Mike Turquette wrote: >>> diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi >>> index f936476..616d9ee 100644 >>> --- a/arch/arm/boot/dts/socfpga.dtsi >>> +++ b/arch/arm/boot/dts/socfpga.dtsi >>> @@ -413,6 +413,7 @@ >>> compatible = "altr,socfpga-gate-clk"; >>> clocks = <&f2s_periph_ref_clk>, <&main_nand_sdmmc_clk>, <&per_nand_mmc_clk>; >>> clk-gate = <0xa0 8>; >>> + clk-phase = <0 3>; >> Looking at this again, I have a hard time understanding the values in >> the clk-phase property. You reference some functions in the property >> definition above, but they are not obvious to me. >> >> Additionally I wonder if the binding would better if the clock-phase >> property was simply the value in degrees. E.g: >> >> clk-phase = <315>; // 315 degrees > I would definitely prefer using degrees over an arbitrary enumeration that > might work on some platforms but not on others. > > I'm also a bit skeptical about the idea of putting the phase into the clock > provider rather than the consumer, given the comments about the > clk_set_phase() interface earlier. Generally we try to avoid having > consumer-specific settings in a provider node (for any DT binding, > not just clocks). Can't you have the same numbers in the dw-mshc > node instead and let the mmc driver call clk_set_phase instead? > If every clock has a fixed phase for a given piece of hardware, it > could even be set automatically by making the common clk code read > the clk-phase attribute at the time a driver calls clk_get. So I think this is what you're suggesting: clocks = <&sdmmc_clk 0 135>, this would specify 0 and 135 degrees phase. The clock-bindings document is stating that the integer in the clocks property is specifying the output number of the clock. Would this approach cause a conflict and would need an update to that document/approach? Dinh > > Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
