hw/clock: Let clock_set() return boolean value

Let clock_set() return a boolean value whether the clock
has been updated or not.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200806123858.30058-3-f4bug@amsat.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 6 insertions, 1 deletions

diff --git a/hw/core/clock.c b/hw/core/clock.c
index 3c0daf7d4c..7066282f7b 100644
--- a/hw/core/clock.c
+++ b/hw/core/clock.c
@@ -34,11 +34,16 @@ void clock_clear_callback(Clock *clk)
     clock_set_callback(clk, NULL, NULL);
 }
 
-void clock_set(Clock *clk, uint64_t period)
+bool clock_set(Clock *clk, uint64_t period)
 {
+    if (clk->period == period) {
+        return false;
+    }
     trace_clock_set(CLOCK_PATH(clk), CLOCK_PERIOD_TO_NS(clk->period),
                     CLOCK_PERIOD_TO_NS(period));
     clk->period = period;
+
+    return true;
 }
 
 static void clock_propagate_period(Clock *clk, bool call_callbacks)