From de6a65f11d7e5a2a93f2b75c0d434ab6ed7f68c8 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 15 Dec 2020 15:09:28 +0000 Subject: [PATCH] clock: Remove clock_get_ns() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Remove the now-unused clock_get_ns() API and the CLOCK_PERIOD_TO_NS() macro that only it was using. Signed-off-by: Peter Maydell Tested-by: Philippe Mathieu-Daudé Reviewed-by: Richard Henderson Reviewed-by: Luc Michel Reviewed-by: Philippe Mathieu-Daudé Message-Id: <20201215150929.30311-4-peter.maydell@linaro.org> Signed-off-by: Philippe Mathieu-Daudé --- docs/devel/clocks.rst | 17 +++++++++++++---- include/hw/clock.h | 6 ------ 2 files changed, 13 insertions(+), 10 deletions(-) diff --git a/docs/devel/clocks.rst b/docs/devel/clocks.rst index c2e70e64db..2d317ff32f 100644 --- a/docs/devel/clocks.rst +++ b/docs/devel/clocks.rst @@ -238,8 +238,17 @@ object during device instance init. For example: Fetching clock frequency/period ------------------------------- -To get the current state of a clock, use the functions ``clock_get()``, -``clock_get_ns()`` or ``clock_get_hz()``. +To get the current state of a clock, use the functions ``clock_get()`` +or ``clock_get_hz()``. + +``clock_get()`` returns the period of the clock in its fully precise +internal representation, as an unsigned 64-bit integer in units of +2^-32 nanoseconds. (For many purposes ``clock_ticks_to_ns()`` will +be more convenient; see the section below on expiry deadlines.) + +``clock_get_hz()`` returns the frequency of the clock, rounded to the +next lowest integer. This implies some inaccuracy due to the rounding, +so be cautious about using it in calculations. It is also possible to register a callback on clock frequency changes. Here is an example: @@ -254,8 +263,8 @@ Here is an example: */ /* do something with the new period */ - fprintf(stdout, "device new period is %" PRIu64 "ns\n", - clock_get_ns(dev->my_clk_input)); + fprintf(stdout, "device new period is %" PRIu64 "* 2^-32 ns\n", + clock_get(dev->my_clk_input)); } Calculating expiry deadlines diff --git a/include/hw/clock.h b/include/hw/clock.h index b5fff6ded8..852c636961 100644 --- a/include/hw/clock.h +++ b/include/hw/clock.h @@ -40,7 +40,6 @@ typedef void ClockCallback(void *opaque); * macro helpers to convert to hertz / nanosecond */ #define CLOCK_PERIOD_FROM_NS(ns) ((ns) * (CLOCK_PERIOD_1SEC / 1000000000llu)) -#define CLOCK_PERIOD_TO_NS(per) ((per) / (CLOCK_PERIOD_1SEC / 1000000000llu)) #define CLOCK_PERIOD_FROM_HZ(hz) (((hz) != 0) ? CLOCK_PERIOD_1SEC / (hz) : 0u) #define CLOCK_PERIOD_TO_HZ(per) (((per) != 0) ? CLOCK_PERIOD_1SEC / (per) : 0u) @@ -215,11 +214,6 @@ static inline unsigned clock_get_hz(Clock *clk) return CLOCK_PERIOD_TO_HZ(clock_get(clk)); } -static inline unsigned clock_get_ns(Clock *clk) -{ - return CLOCK_PERIOD_TO_NS(clock_get(clk)); -} - /** * clock_ticks_to_ns: * @clk: the clock to query