Grant Likely wrote: > On Wed, Apr 8, 2009 at 12:16 AM, Wolfgang Grandegger <w...@grandegger.com> > wrote: >> Grant Likely wrote: >>> On Tue, Apr 7, 2009 at 1:20 AM, Wolfgang Grandegger <w...@grandegger.com> >>> wrote: >>>> Preserve I2C clock settings for the Socrates MPC8544 board. >>> I had thought that the preserve-clocking property was intended for >>> older boards that don't currently have any method of getting the clock >>> setting out of u-boot. Since Socrates is a new board, U-Boot should >>> probably be made to fill in the real clock rate setting. >> I'm not sure if I understand what you mean. If an old version of U-Boot >> on an old board sets the I2C clock, it can be used (inherited) by Linux >> using the property "preserve-clocking". >> >> It is actually the customers choice to set the I2C clock in U-Boot and >> re-use it by Linux. > > Setting it in the register != recording the value in the device tree. > I'm saying that since Socrates is a new board it should not use the > preserve-clocking dirty trick (and it is a dirty trick) because the > correct clocking data can be passed via the device tree.
Why should an old board then use it. "fsl, preserve-clocking" is a new feature, like using "clock-frequency" and you have the choice to explicitly set the clocking via device tree or inherit it from the boot loader. So far, a fixed FDR/DFRSS value (0x1031) was written to the registers by Linux. Wolfgang. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
