clock: Add ClockEvent parameter to callbacks

The Clock framework allows users to specify a callback which is
called after the clock's period has been updated.  Some users need to
also have a callback which is called before the clock period is
updated.

As the first step in adding support for notifying Clock users on
pre-update events, add an argument to the ClockCallback to specify
what event is being notified, and add an argument to the various
functions for registering a callback to specify which events are
of interest to that callback.

Note that the documentation update renders correct the previously
incorrect claim in 'Adding a new clock' that callbacks "will be
explained in a following section".

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Luc Michel <luc@lmichel.fr>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210219144617.4782-2-peter.maydell@linaro.org

1 files changed, 3 insertions, 2 deletions

diff --git a/hw/misc/zynq_slcr.c b/hw/misc/zynq_slcr.c
index 66504a9d3a..c66d7db177 100644
--- a/hw/misc/zynq_slcr.c
+++ b/hw/misc/zynq_slcr.c
@@ -307,9 +307,10 @@ static void zynq_slcr_propagate_clocks(ZynqSLCRState *s)
     clock_propagate(s->uart1_ref_clk);
 }
 
-static void zynq_slcr_ps_clk_callback(void *opaque)
+static void zynq_slcr_ps_clk_callback(void *opaque, ClockEvent event)
 {
     ZynqSLCRState *s = (ZynqSLCRState *) opaque;
+
     zynq_slcr_compute_clocks(s);
     zynq_slcr_propagate_clocks(s);
 }
@@ -576,7 +577,7 @@ static const MemoryRegionOps slcr_ops = {
 };
 
 static const ClockPortInitArray zynq_slcr_clocks = {
-    QDEV_CLOCK_IN(ZynqSLCRState, ps_clk, zynq_slcr_ps_clk_callback),
+    QDEV_CLOCK_IN(ZynqSLCRState, ps_clk, zynq_slcr_ps_clk_callback, ClockUpdate),
     QDEV_CLOCK_OUT(ZynqSLCRState, uart0_ref_clk),
     QDEV_CLOCK_OUT(ZynqSLCRState, uart1_ref_clk),
     QDEV_CLOCK_END