On Mon, Sep 16, 2013 at 10:34:28AM -0600, Stephen Warren wrote: > On 09/12/2013 06:55 PM, Soren Brinkmann wrote: > > Add a driver for SILabs 570, 571, 598, 599 programmable oscillators. > > The devices generate low-jitter clock signals and are reprogrammable via > > an I2C interface. > > > diff --git a/Documentation/devicetree/bindings/clock/silabs,si570.txt b/Documentation/devicetree/bindings/clock/silabs,si570.txt > > > +Required properties: > > + - compatible: Shall be one of "silabs,si57x", "silabs,si59x". > > + - reg: I2C device address. > > + - #clock-cells: From common clock bindings: Shall be 0. > > + - factory-fout: Factory set default frequency > > So, there's no way to query this from the device at all? Looking at the > data-sheet, all the frequency generation parameters are in registers, > and the device supports I2C read commands. As such, I'm not convinced > this property is necessary. > Unfortunately, the chip does not report the factory setting for fout, so the property is needed. The chip can not be programmed without it. > > +Optional properties: > > + - initial-fout: Initial output frequency to set during probe > > "probe" is a Linux-specific concept. This property should be removed. If > the driver is asked to set a specific frequency, it should do so, but I > don't think it should program something pro-actively just because it > starts up. > > If this property is acceptable, it'd be better to describe it more along > the lines of the following: > > initial-fout: The frequency at which the system requires the clock to > operate. > It should probably be something like "clock-frequency". In many use cases the programmed frequency is set to a constant frequency at system startup and never changed, similar to other clocks. Guenter > > + - temperature-stability-7ppm: Indicate a device with a temperature stability > > + of 7ppm > > + > > +Example: > > + si570: clock-generator@5d { > > + #clock-cells = <0>; > > + compatible = "silabs,si570"; > > + reg = <0x5d>; > > + factory-fout = <156250000>; > > + }; > > -- 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