Re: [PATCH 3/4] watchdog: sa11x0/pxa: get rid of get_clock_tick_rate

From: Russell King - ARM Linux
Date: Mon Sep 19 2016 - 18:37:00 EST

On Mon, Sep 19, 2016 at 01:08:16PM -0700, Guenter Roeck wrote:
> On Mon, Sep 19, 2016 at 09:12:14PM +0200, Robert Jarzmik wrote:
> > The OS timer rate used for the watchdog can now be fetched from the
> > standard clock API. This will remove the last user of
> > get_clock_tick_rate() in both pxa and sa11x0 architectures.
> >
> > Signed-off-by: Robert Jarzmik <robert.jarzmik@xxxxxxx>
> Did you test this ? Potential problem, if built into the kernel, could be that
> the clocks might not be ready by the time the driver is instantiated. Unless
> this is converted to a platform driver, it won't be able to handle a
> -EPROBE_DEFER from the clock subsystem.

Really not a problem at all. The OSTIMER0 is required for the system
tick, and if that's not present, the kernel will be without any kind
of time keeping, so a missing watchdog driver is the least of the

Therefore, both PXA and SA11x0 register their clocks really early to
ensure that OSTIMER0 is available by the time_init() stage, which is
way before driver probe time.

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