[PATCH 4/9] clk: Add clock driver for mb86s7x

On Friday 21 November 2014 23:28:38 Jassi Brar wrote:

On 21 November 2014 22:45, Arnd Bergmann [off-list ref] wrote:

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On Friday 21 November 2014 22:06:51 Jassi Brar wrote:

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Only MB86S70_CRG11_UNGPRT is marked to mean one special (non-maskable)
port on the controller, which the clock driver does make use of.

Is this the actual port number that is known to be non-maskable?

Yes the clock comes out of the controller and is also the parent of
other 8 independently maskable clock ports of the domain.

I'm getting confused by the terminology here. Is MB86S70_CRG11_ALW
a port or a controller?

Sorry, bad symbols. ALW..DPHY are controllers. UNGPRT is the ninth
parent clock (port) of a domain that can't be masked.
FYKI, there are 6 instances, of some CRG11 clock controller, under
control of the remote f/w. The Mailbox protocol between remote f/w and
Linux assigned indices [0-5] to these controllers.

Ok, not it makes sense, thanks for clearing that up!

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 The firmware on remote master, lets say, don't wanna be bothered by
the clock topology. Even for set-rate the onus is on Linux to request
only appropriate rates at appropriate times so that other devices are
not messed up.

Is there any code to validate that, or does Linux just treat all
clocks transparently?

The remote does not expose the clock topology and only accepts
requests on port-basis. The remote f/w is supposed to keep track of
which ports are used by Linux and then work out inter-dependencies
upon receiving a request from Linux. So for Linux there are N
independent 'root' clocks, ops on which may or may not succeed at any
given time.

Ok.

	Arnd