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, 2 insertions, 2 deletions

diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c
index c603e14012..ceb677bc5a 100644
--- a/hw/char/cadence_uart.c
+++ b/hw/char/cadence_uart.c
@@ -519,7 +519,7 @@ static void cadence_uart_realize(DeviceState *dev, Error **errp)
                              uart_event, NULL, s, NULL, true);
 }
 
-static void cadence_uart_refclk_update(void *opaque)
+static void cadence_uart_refclk_update(void *opaque, ClockEvent event)
 {
     CadenceUARTState *s = opaque;
 
@@ -537,7 +537,7 @@ static void cadence_uart_init(Object *obj)
     sysbus_init_irq(sbd, &s->irq);
 
     s->refclk = qdev_init_clock_in(DEVICE(obj), "refclk",
-            cadence_uart_refclk_update, s);
+                                   cadence_uart_refclk_update, s, ClockUpdate);
     /* initialize the frequency in case the clock remains unconnected */
     clock_set_hz(s->refclk, UART_DEFAULT_REF_CLK);