docs/devel/clocks.rst

148 At creation, the period of the clock is 0: the clock is disabled. You can
151 Note that if you are creating a clock with a fixed period which will never
152 change (for example the main clock source of a board), then you'll have
160 You can give a clock a callback function in several ways:
178 When you register the callback you specify a mask of ClockEvent values
179 that you are interested in. The callback will only be called for those
194 different functions for different events. You must register a single
195 callback which listens for all of the events you are interested in,
269 mechanism so you can configure a clock to make its children
270 run at a different period from its own. If you call the
271 ``clock_set_mul_div()`` function you can specify the clock's
274 For instance, if the clock has a frequency of 8MHz and you set its
278 You can change the multiplier and divider of a clock at runtime,
279 so you can use this to model clock controller devices which
287 ``clock_propagate()``. If you make a runtime change to the
288 multiplier or divider you must call clock_propagate() yourself.
307 To enforce that the clock is wired up by the board code, you can
320 zero. You should use the clock callback to find out when the clock
356 If you are only interested in the frequency for displaying it to
391 (If you are performing further calculations on the returned value
393 ``timer_mod_ns()`` then you should be careful to avoid overflow
399 For calculations where you need to know the number of ticks in
502 vmstate description. You should use the ``VMSTATE_CLOCK`` macro for this.
527 When adding clock support to an existing device, if you care about
528 migration compatibility you will need to be careful, as simply adding
529 a ``VMSTATE_CLOCK()`` line will break compatibility. Instead, you can