clocksource: sh_cmt: __clocksource_updatefreq_hz() update (3593f5fe) · Commits · 戴 / test

This patch updates the clocksource part of the CMT driver to make use of the __clocksource_updatefreq_hz() function. Without this patch the old code uses clocksource_register() together with a hack that assumes a never changing clock rate (see clk_enable(), clk_get_rate() and clk_disable()). The patch uses clocksource_register_hz() with 1 Hz as initial value, then lets the ->enable() callback update the value with __clocksource_updatefreq_hz() once the struct clk has been enabled and the frequency is stable. Signed-off-by:

Magnus Damm <damm@opensource.se> Acked-by:

John Stultz <johnstul@us.ibm.com> Signed-off-by:

Paul Mundt <lethal@linux-sh.org>

drivers/clocksource/sh_cmt.c

+7 −12

Original line number	Diff line number	Diff line
		@@ -416,11 +416,15 @@ static cycle_t sh_cmt_clocksource_read(struct clocksource *cs)

		static int sh_cmt_clocksource_enable(struct clocksource *cs)
		{
		int ret;
		struct sh_cmt_priv *p = cs_to_sh_cmt(cs);

		p->total_cycles = 0;

		return sh_cmt_start(p, FLAG_CLOCKSOURCE);
		ret = sh_cmt_start(p, FLAG_CLOCKSOURCE);
		if (!ret)
		__clocksource_updatefreq_hz(cs, p->rate);
		return ret;
		}

		static void sh_cmt_clocksource_disable(struct clocksource *cs)
		@@ -448,19 +452,10 @@ static int sh_cmt_register_clocksource(struct sh_cmt_priv *p,
		cs->mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8);
		cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;

		/* clk_get_rate() needs an enabled clock */
		clk_enable(p->clk);
		p->rate = clk_get_rate(p->clk) / ((p->width == 16) ? 512 : 8);
		clk_disable(p->clk);

		/* TODO: calculate good shift from rate and counter bit width */
		cs->shift = 0;
		cs->mult = clocksource_hz2mult(p->rate, cs->shift);

		dev_info(&p->pdev->dev, "used as clock source\n");

		clocksource_register(cs);

		/* Register with dummy 1 Hz value, gets updated in ->enable() */
		clocksource_register_hz(cs, 1);
		return 0;
		}

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