[PATCH v4 5/6] clocksource: armada-370-xp: Fix device-tree binding

Tomasz Figa tomasz.figa at gmail.com
Sat Aug 17 08:34:23 EDT 2013


On Saturday 17 of August 2013 14:29:28 Sebastian Hesselbarth wrote:
> On 08/17/2013 02:09 PM, Tomasz Figa wrote:
> > On Friday 16 of August 2013 17:29:00 Stephen Warren wrote:
> >> On 08/15/2013 10:27 AM, Ezequiel Garcia wrote:
> >> ...
> >> 
> >>> Armada XP
> >>> ---------
> >>> 
> >>> Two clock sources are available for timer and watchdog counters:
> >>> 
> >>> Just as explained for the Armada 370, the timer and watchdog
> >>> counters
> >>> decrement rate is a configurable ratio of the L2/coherency fabric
> >>> clock. The current clocksource driver implementation chooses an
> >>> abritrary ratio.
> >>> 
> >>> In addition to this, both timer and watchdog counter rate can be
> >>> configured to use an (internal) 25 MHz fixed clock.
> >> 
> >> So there are clearly two clocks fed into the HW block here. The DT
> >> should reflect that.
> > 
> > I fully agree. DT should list all the input clocks that are fed into
> > the IP block being described.
> 
> I don't object to the above, but strictly speaking the consequence
> would be, that all nodes require a clocks property.

Well, I should have added something like "if this is relevant to the IP 
being described", e.g. it can select its operating or I/O clock from those 
input clocks.

> For A370/XP timer
> the fabric clock is configurable and needs to be passed among core
> clocks and timer, the 25MHz clock is not and _could_ be seen as an extra
> feature of the core.

Well, so the core allows selection between both clocks and so both should 
be listed IMHO.

Best regards,
Tomasz




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