Timur Tabi wrote: > Wolfgang Grandegger wrote: > >> No, the source clock is not identical for all 8[356]xx. Some use half or >> even a third of the SOC clock frequency. > > The platform clock divided by 2 or 3 *is* the source clock to the I2C. That's > what I'm talking about. > >> Linux must determine the real >> source clock frequency somehow. We may introduce the SOC property >> "i2c-clock-frequency", which could be fixed up by U-Boot or a pre-loader >> (in case U-Boot is not used). Like for other frequency properties as well. > > That's what I'm proposing, but drop the "i2c-".
But clock-frequency, aka bus-frequency, is already used by fsl_get_sys_freq(): http://lxr.linux.no/linux+v2.6.26/arch/powerpc/sysdev/fsl_soc.c#L80 Thinking more about it, it would be best to add the property "i2c-clock-divider" to the soc node and implement fsl_get_i2c_freq() in a similar way: [EMAIL PROTECTED] { #address-cells = <1>; #size-cells = <1>; device_type = "soc"; ranges = <0x0 0xe0000000 0x100000>; reg = <0xe0000000 0x1000>; // CCSRBAR 1M bus-frequency = <0>; i2c-clock-divider = <2>; U-Boot could then fixup that value like bus-frequency() and the i2c-mpc driver simply calls fsl_get_i2c_freq(). Wolfgang. _______________________________________________ i2c mailing list i2c@lm-sensors.org http://lists.lm-sensors.org/mailman/listinfo/i2c