Hello Mark, On 10/23/2014 06:26 AM, Mark Rutland wrote: >>>> +- clocks >>>> + Usage: See clock-bindings.txt and qoriq-clock.txt >>>> + Value type: <prop-encoded-array> >>>> + Definition: Half of the platform clock >>>> + >>> >>> I don't understand the description here. What is the clock from the PoV >>> of the QMan? Which input line on the QMan is this clock attached to? >>> >>> Is there only one clock input? Or jsut one that you need to manage at >>> the moment? >> >> As part of the programming model (QoS features specifically) QMan needs >> to know its clock speed. Prior to the existence of the >> clock-bindings.txt, a "static" clock-frequency property was/is used >> convey such information. Using clock-binding.txt to describe the >> clocking hierarchy in the SoC makes it easier with DFS, power >> management, etc. > > Ok. My concern is the phrase "Half of the platform clock" is meaingless. > The property contains a phandle + clock-specifier pair that describe a > single input clock by reference (some bindings just say "clock > reference" for that, which is fine). This is not "half" of any > particular clock. > > The description of the clock should describe what it logically is from > the PoV of the consumer (i.e. _this_ device) rather than the provider. > To me "platform clock" sounds like a description of the provider. Is > there a name for the clock input line on this device? > > Is there only a single clock input? Or just one that you care about at > the moment? This is the reference clock for QMan and is the only input clock. It's derived form the platform PLL/clock and its frequency/speed is half of the platform PLL. I'll update its description Cheers, -- 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
