On 7/31/08, Scott Wood <[EMAIL PROTECTED]> wrote:
> Timur Tabi wrote:
>
> > Grant Likely wrote:
> >
> >
> > > No it doesn't, it depends on the register interface to decide
> > > compatibility. Clock interface is part of that.
> > >
> >
> > I don't think so. The interface for programming the clock registers is
> > identical on all 8[356]xx parts. The only thing that matters is what
> specific
> > values to put in the FDR and DFSR registers to get a desired I2C bus
> speed.
> >
>
> If it affects the values you need to write to the registers to achieve a
> given result, how is it not a difference in the register interface?
>
>
> > I propose the property "clock-frequency", like this:
> >
> > [EMAIL PROTECTED] {
> > #address-cells = <1>;
> > #size-cells = <0>;
> > cell-index = <0>;
> > compatible = "fsl-i2c";
> > reg = <0x3000 0x100>;
> > interrupts = <14 0x8>;
> > interrupt-parent = <&ipic>;
> > dfsrr;
> > clock-frequency = <0xblablabla>; <-- added by
> U-Boot
> > };
> >
>
> A clock-frequency property is OK, and is in line with what we do in other
> types of nodes. However, in the long run it might be nice to introduce some
> sort of clock binding where, for example, the i2c node can point to a clock
> elsewhere in the device tree as an input clock.
>
> That way, less knowledge is required by the firmware to poke values all
> over the place, and it also allows one to describe situations where the
> frequency of the input clock can change (such as in low-power modes).
PowerPC,[EMAIL PROTECTED] {
timebase-frequency = <0>; /* From Bootloader */
bus-frequency = <0>; /* From Bootloader */
clock-frequency = <0>; /* From Bootloader */
};
The mpc5200 code already has mpc52xx_find_ipb_freq() to get it.
I should grep before suggesting things.
--
Jon Smirl
[EMAIL PROTECTED]
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