[RFC,PATCH 2/3] clk: Generic support for fixed-rate clocks
Jeremy Kerr
jeremy.kerr at canonical.com
Tue Feb 15 01:18:37 EST 2011
Hi Saravana,
> >> A fixed clock may still have other operations such as enable/disable.
> >
> > Then it's not a fixed clock; I'd prefer this to be a separate type, as
> > it's now hardware dependent.
>
> I'm confused. If a clock's rate can't be changed and it can't be enabled
> or disabled, then what's the point of representing that clock
> signal/line as a clock in the driver.
Because the drivers using this clock don't know that it's a fixed clock.
For example, a uart needs to know the rate of its clock source, so that it can
set its internal divisors to get a valid baud rate. The uart driver will query
the input rate using clk_get_rate(). The driver still needs to call
clk_enable/clk_prepare/etc, because on some systems it may have a switchable
clock.
Cheers,
Jeremy
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