On Wednesday 15 July 2015 11:00:59 Linus Walleij wrote: > On Wed, Jul 8, 2015 at 4:53 AM, Simon Glass <sjg@xxxxxxxxxxxx> wrote: > > > This binding differs from that of Linux. Update it and change existing > > users. > > > > Signed-off-by: Simon Glass <sjg@xxxxxxxxxxxx> > > I'm confused by this. Isn't devicetree@xxxxxxxxxxxxxxx the place to discuss > device tree bindings? This is sent only to the U-Boot list, does this mean > that there will now be *two* ontologies for DT bindings? That sounds like > a recepie for ... something not good. > > > +- clock-frequency: > > + Input clock frequency for UART. > > This is the real trick is it not? > > Is the real commit blurb for this patch something like: > > "we want a simple way to look up the clock frequency for our serial > ports during early boot, and following clocks = <&...> phandles > is too much trouble and might imply having to implement a whole > clock framework in U-Boot so we just see a lot of trouble, instead > provide a default frequency here" > > I suggest in that case, instead do this: > > - boot-frequency: > input clock frequency at boot time, to be used by boot loaders > and other early access. > > This would be good for early Linux stuff as well I believe and I > do not think it's very controversial. The CHRP ISA binding defines that a 8250 compatible UART must have this property: "clock-frequency" S Standard property, encoded as with encode-int, that shall be the baud-rate generator's clock input frequency (in hertz). Typically, the clock frequency is nominally 1,843,200 Hz. Some devices generate the baud rate input clock by dividing a higher-frequency clock source that is not an exact multiple of 1,843,200 Hz, resulting in a small but acceptable error in the nominal clock frequency. In such cases, the "clock-frequency" shall report the actual nominal frequency. For example, if the baud rate input clock is generated by dividing a 24 MHz clock by 13, the value of the "clock-frequency" property shall be 1846153. Arnd -- 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
